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Note: This page contains sample records for the topic "massively parallel microcell-based" from the National Library of EnergyBeta (NLEBeta).
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1

Massively parallel neural computation  

E-Print Network (OSTI)

work and includes nothing which is the outcome of work done in collaboration except where specifically indicated in the text. This dissertation does not exceed the regulation length of 60 000 words, including tables and footnotes. Massively Parallel... -flow pipeline (Thomas and Luk, 2009; Cas- sidy et al., 2011; Martinez-Alvarez et al., 2007; Rice et al., 2009). Mathematical neuron models are amenable to being converted to pipelines with many stages (Rice et al. use 23 stages for an Izhikevich neuron model...

Fox, Paul James

2013-03-12T23:59:59.000Z

2

Massively parallel computing system  

DOE Patents (OSTI)

A parallel computing system and method having improved performance where a program is concurrently run on a plurality of nodes for reducing total processing time, each node having a processor, a memory, and a predetermined number of communication channels connected to the node and independently connected directly to other nodes. The present invention improves performance of the parallel computing system by providing a system which can provide efficient communication between the processors and between the system and input and output devices. A method is also disclosed which can locate defective nodes with the computing system.

Benner, R.E.; Gustafson, J.L.; Montry, G.R.

1989-03-01T23:59:59.000Z

3

Template based parallel checkpointing in a massively parallel computer system  

DOE Patents (OSTI)

A method and apparatus for a template based parallel checkpoint save for a massively parallel super computer system using a parallel variation of the rsync protocol, and network broadcast. In preferred embodiments, the checkpoint data for each node is compared to a template checkpoint file that resides in the storage and that was previously produced. Embodiments herein greatly decrease the amount of data that must be transmitted and stored for faster checkpointing and increased efficiency of the computer system. Embodiments are directed to a parallel computer system with nodes arranged in a cluster with a high speed interconnect that can perform broadcast communication. The checkpoint contains a set of actual small data blocks with their corresponding checksums from all nodes in the system. The data blocks may be compressed using conventional non-lossy data compression algorithms to further reduce the overall checkpoint size.

Archer, Charles Jens (Rochester, MN); Inglett, Todd Alan (Rochester, MN)

2009-01-13T23:59:59.000Z

4

MASSIVE HYBRID PARALLELISM FOR FULLY IMPLICIT MULTIPHYSICS  

SciTech Connect

As hardware advances continue to modify the supercomputing landscape, traditional scientific software development practices will become more outdated, ineffective, and inefficient. The process of rewriting/retooling existing software for new architectures is a Sisyphean task, and results in substantial hours of development time, effort, and money. Software libraries which provide an abstraction of the resources provided by such architectures are therefore essential if the computational engineering and science communities are to continue to flourish in this modern computing environment. The Multiphysics Object Oriented Simulation Environment (MOOSE) framework enables complex multiphysics analysis tools to be built rapidly by scientists, engineers, and domain specialists, while also allowing them to both take advantage of current HPC architectures, and efficiently prepare for future supercomputer designs. MOOSE employs a hybrid shared-memory and distributed-memory parallel model and provides a complete and consistent interface for creating multiphysics analysis tools. In this paper, a brief discussion of the mathematical algorithms underlying the framework and the internal object-oriented hybrid parallel design are given. Representative massively parallel results from several applications areas are presented, and a brief discussion of future areas of research for the framework are provided.

Cody J. Permann; David Andrs; John W. Peterson; Derek R. Gaston

2013-05-01T23:59:59.000Z

5

Massively Parallel Molecular Statics Simulations of the Percolation ...  

Science Conference Proceedings (OSTI)

Presentation Title, Massively Parallel Molecular Statics Simulations of the Percolation of Dislocations through a Random Array of Forest Dislocation Obstacles in ...

6

Performance of Massively Parallel Computers for Spectral Atmospheric Models  

Science Conference Proceedings (OSTI)

Massively parallel processing (MPP) computer systems use high-speed interconnection networks to link hundreds or thousands of RISC microprocessors. With each microprocessor having a peak performance of 100 or more megaflops per second, there is ...

Ian T. Foster; Brian Toonen; Patrick H. Worley

1996-10-01T23:59:59.000Z

7

Overcoming Communication Latency Barriers in Massively Parallel Scientific Computation  

Science Conference Proceedings (OSTI)

Anton, a massively parallel special-purpose machine that accelerates molecular dynamics simulations by orders of magnitude, uses a combination of specialized hardware mechanisms and restructured software algorithms to reduce and hide communication latency. ... Keywords: Data communications, interprocessor communications, multiprocessor systems, network communication, parallel systems, special-purpose hardware, Anton

Ron Dror; J. P. Grossman; Kenneth Mackenzie; Brian Towles; Edmond Chow; John Salmon; Cliff Young; Joseph Bank; Brannon Batson; David Shaw; Jeffrey S. Kuskin; Richard H. Larson; Mark A. Moraes; David E. Shaw

2011-05-01T23:59:59.000Z

8

BlueGene/L applications: Parallelism On a Massive Scale  

Science Conference Proceedings (OSTI)

BlueGene/L (BG/L), developed through a partnership between IBM and Lawrence Livermore National Laboratory (LLNL), is currently the world's largest system both in terms of scale, with 131,072 processors, and absolute performance, with a peak rate of ... Keywords: BlueGene/L, application scalability, massively parallel architectures, performance study and optimization

Bronis R. De Supinski; Martin Schulz; Vasily V. Bulatov; William Cabot; Bor Chan; Andrew W. Cook; Erik W. Draeger; James N. Glosli; Jeffrey A. Greenough; Keith Henderson; Alison Kubota; Steve Louis; Brian J. Miller; Mehul V. Patel; Thomas E. Spelce; Frederick H. Streitz; Peter L. Williams; Robert K. Yates; Andy Yoo; George Almasi; Gyan Bhanot; Alan Gara; John A. Gunnels; Manish Gupta; Jose Moreira; James Sexton; Bob Walkup; Charles Archer; Francois Gygi; Timothy C. Germann; Kai Kadau; Peter S. Lomdahl; Charles Rendleman; Michael L. Welcome; William Mclendon; Bruce Hendrickson; Franz Franchetti; Stefan Kral; Jürgen Lorenz; Christoph W. Überhuber; Edmond Chow; Ümit Çatalyürek

2008-02-01T23:59:59.000Z

9

A heterogeneous graphics procedure for visualization of massively parallel solutions  

SciTech Connect

Scientific visualization is playing an increasingly important role in the analysis and interpretation of massively parallel CFD simulations due to the enormous volume of data that can be generated on these machines. In this paper we will describe the development of a visualization technique based on a parallel analogue to the Marching Cubes algorithm. The algorithm has been developed for Multiple-Instruction, Multiple-Data (MIMD) massively parallel computers and is designed to take advantage of the heterogeneous programming capabilities of the MIMD architecture. We examine several different configurations and conclude that for producing animations the best one, in terms of both frame generation time and disk usage, is to run the two applications heterogeneously and send the resulting geometry description directly to a workstation for rendering, thereby totally eliminating the use of files from the animation process.

1993-01-01T23:59:59.000Z

10

A heterogeneous graphics procedure for visualization of massively parallel solutions  

SciTech Connect

Scientific visualization is playing an increasingly important role in the analysis and interpretation of massively parallel CFD simulations due to the enormous volume of data that can be generated on these machines. In this paper we will describe the development of a visualization technique based on a parallel analogue to the Marching Cubes algorithm. The algorithm has been developed for Multiple-Instruction, Multiple-Data (MIMD) massively parallel computers and is designed to take advantage of the heterogeneous programming capabilities of the MIMD architecture. We examine several different configurations and conclude that for producing animations the best one, in terms of both frame generation time and disk usage, is to run the two applications heterogeneously and send the resulting geometry description directly to a workstation for rendering, thereby totally eliminating the use of files from the animation process.

1993-03-01T23:59:59.000Z

11

Massively parallel Wang Landau sampling on multiple GPUs  

Science Conference Proceedings (OSTI)

Wang Landau sampling is implemented on the Graphics Processing Unit (GPU) with the Compute Unified Device Architecture (CUDA). Performances on three different GPU cards, including the new generation Fermi architecture card, are compared with that on a Central Processing Unit (CPU). The parameters for massively parallel Wang Landau sampling are tuned in order to achieve fast convergence. For simulations of the water cluster systems, we obtain an average of over 50 times speedup for a given workload.

Yin, Junqi [ORNL; Landau, D. P. [UGA

2012-01-01T23:59:59.000Z

12

The Evolution of the Massively Parallel Processing Database in Support of Visual Analytics  

Science Conference Proceedings (OSTI)

This article explores the evolution of the Massively Parallel Processing MPP database, focusing on trends of particular relevance to analytics. The dramatic shift of database vendors and leading companies to utilize MPP databases and deploy an Enterprise ... Keywords: Decision Support Workload, Enterprise Analytics, Enterprise Data Warehouse EDW, Massively Parallel Processing MPP Database, Visual Analytics

Ian A. Willson

2011-10-01T23:59:59.000Z

13

GPA a tool for fluid scalability analysis of massively parallel systems  

E-Print Network (OSTI)

analysis, GPA first generates an abstract representation of the system of ODEs and then dynamically. Hayden, and J. T. Bradley, "Fluid Analysis of Energy Consumption using Rewards in Massively ParallelGPA ­ a tool for fluid scalability analysis of massively parallel systems Anton Stefanek Richard A

Imperial College, London

14

High-quality draft assemblies of mammalian genomes from massively parallel sequence data  

E-Print Network (OSTI)

Massively parallel DNA sequencing technologies are revolutionizing genomics by making it possible to generate billions of relatively short (~100-base) sequence reads at very low cost. Whereas such data can be readily used ...

Gnerre, Sante

15

A massively space-time parallel N-body solver  

Science Conference Proceedings (OSTI)

We present a novel space-time parallel version of the Barnes-Hut tree code pepc using pfasst, the Parallel Full Approximation Scheme in Space and Time. The naive use of increasingly more processors for a fixed-size N-body problem is prone to saturate ...

R. Speck; D. Ruprecht; R. Krause; M. Emmett; M. Minion; M. Winkel; P. Gibbon

2012-11-01T23:59:59.000Z

16

SWAMP+: multiple subsequence alignment using associative massive parallelism  

SciTech Connect

A new parallel algorithm SWAMP+ incorporates the Smith-Waterman sequence alignment on an associative parallel model known as ASC. It is a highly sensitive parallel approach that expands traditional pairwise sequence alignment. This is the first parallel algorithm to provide multiple non-overlapping, non-intersecting subsequence alignments with the accuracy of Smith-Waterman. The efficient algorithm provides multiple alignments similar to BLAST while creating a better workflow for the end users. The parallel portions of the code run in O(m+n) time using m processors. When m = n, the algorithmic analysis becomes O(n) with a coefficient of two, yielding a linear speedup. Implementation of the algorithm on the SIMD ClearSpeed CSX620 confirms this theoretical linear speedup with real timings.

Steinfadt, Shannon Irene [Los Alamos National Laboratory; Baker, Johnnie W [KENT STATE UNIV.

2010-10-18T23:59:59.000Z

17

Massively parallel genomic sequence search on the Blue Gene/P architecture  

Science Conference Proceedings (OSTI)

This paper presents our first experiences in mapping and optimizing genomic sequence search onto the massively parallel IBM Blue Gene/P (BG/P) platform. Specifically, we performed our work on mpiBLAST, a parallel sequence-search code that has been optimized ...

Heshan Lin; Pavan Balaji; Ruth Poole; Carlos Sosa; Xiaosong Ma; Wu-chun Feng

2008-11-01T23:59:59.000Z

18

A Massively Parallel Adaptive Fast Multipole Method on Heterogeneous Architectures  

Science Conference Proceedings (OSTI)

We describe a parallel fast multipole method (FMM) for highly nonuniform distributions of particles. We employ both distributed memory parallelism (via MPI) and shared memory parallelism (via OpenMP and GPU acceleration) to rapidly evaluate two-body nonoscillatory potentials in three dimensions on heterogeneous high performance computing architectures. We have performed scalability tests with up to 30 billion particles on 196,608 cores on the AMD/CRAY-based Jaguar system at ORNL. On a GPU-enabled system (NSF's Keeneland at Georgia Tech/ORNL), we observed 30x speedup over a single core CPU and 7x speedup over a multicore CPU implementation. By combining GPUs with MPI, we achieve less than 10 ns/particle and six digits of accuracy for a run with 48 million nonuniformly distributed particles on 192 GPUs.

Lashuk, Ilya [Lawrence Livermore National Laboratory (LLNL); Chandramowlishwaran, Aparna [Georgia Institute of Technology; Langston, Harper [Georgia Institute of Technology; Nguyen, Tuan-Anh [Georgia Institute of Technology; Sampath, Rahul S [ORNL; Shringarpure, Aashay [Georgia Institute of Technology; Vuduc, Richard [Georgia Institute of Technology; Ying, Lexing [University of Texas, Austin; Zorin, Denis [New York University; Biros, George [University of Texas, Austin

2012-01-01T23:59:59.000Z

19

Massively parallel Monte Carlo for many-particle simulations on GPUs  

E-Print Network (OSTI)

Current trends in parallel processors call for the design of efficient massively parallel algorithms for scientific computing. Parallel algorithms for Monte Carlo simulations of thermodynamic ensembles of particles have received little attention because of the inherent serial nature of the statistical sampling. In this paper, we present a massively parallel method that obeys detailed balance and implement it for a system of hard disks on the GPU. We reproduce results of serial high-precision Monte Carlo runs to verify the method. This is a good test case because the hard disk equation of state over the range where the liquid transforms into the solid is particularly sensitive to small deviations away from the balance conditions. On a Tesla K20, our GPU implementation executes over one billion trial moves per second, which is 148 times faster than on a single Intel Xeon E5540 CPU core, enables 27 times better performance per dollar, and cuts energy usage by a factor of 13. With this improved performance we are able to calculate the equation of state for systems of up to one million hard disks. These large system sizes are required in order to probe the nature of the melting transition, which has been debated for the last forty years. In this paper we present the details of our computational method, and discuss the thermodynamics of hard disks separately in a companion paper.

Joshua A. Anderson; Eric Jankowski; Thomas L. Grubb; Michael Engel; Sharon C. Glotzer

2012-11-07T23:59:59.000Z

20

Molecular Dynamics Simulations from SNL's Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS)  

DOE Data Explorer (OSTI)

LAMMPS (http://lammps.sandia.gov/index.html) stands for Large-scale Atomic/Molecular Massively Parallel Simulator and is a code that can be used to model atoms or, as the LAMMPS website says, as a parallel particle simulator at the atomic, meso, or continuum scale. This Sandia-based website provides a long list of animations from large simulations. These were created using different visualization packages to read LAMMPS output, and each one provides the name of the PI and a brief description of the work done or visualization package used. See also the static images produced from simulations at http://lammps.sandia.gov/pictures.html The foundation paper for LAMMPS is: S. Plimpton, Fast Parallel Algorithms for Short-Range Molecular Dynamics, J Comp Phys, 117, 1-19 (1995), but the website also lists other papers describing contributions to LAMMPS over the years.

Plimpton, Steve; Thompson, Aidan; Crozier, Paul

Note: This page contains sample records for the topic "massively parallel microcell-based" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Initial Testing of a Massively Parallel Ensemble Kalman Filter with the Poseidon Isopycnal Ocean General Circulation Model  

Science Conference Proceedings (OSTI)

A multivariate ensemble Kalman filter (MvEnKF) implemented on a massively parallel computer architecture has been developed for the Poseidon ocean circulation model and tested with a Pacific basin model configuration. There are about 2 million ...

Christian L. Keppenne; Michele M. Rienecker

2002-12-01T23:59:59.000Z

22

An Investigation into Reliability, Availability, and Serviceability (RAS) Features for Massively Parallel Processor Systems  

SciTech Connect

A study has been completed into the RAS features necessary for Massively Parallel Processor (MPP) systems. As part of this research, a use case model was built of how RAS features would be employed in an operational MPP system. Use cases are an effective way to specify requirements so that all involved parties can easily understand them. This technique is in contrast to laundry lists of requirements that are subject to misunderstanding as they are without context. As documented in the use case model, the study included a look at incorporating system software and end-user applications, as well as hardware, into the RAS system.

KELLY, SUZANNE M.; OGDEN, JEFFREY BRANDON

2002-10-01T23:59:59.000Z

23

A massively parallel semi-Lagrangian algorithm for solving the transport equation  

SciTech Connect

The scalar transport equation underpins many models employed in science, engineering, technology and business. Application areas include, but are not restricted to, pollution transport, weather forecasting, video analysis and encoding (the optical flow equation), options and stock pricing (the Black-Scholes equation) and spatially explicit ecological models. Unfortunately finding numerical solutions to this equation which are fast and accurate is not trivial. Moreover, finding such numerical algorithms that can be implemented on high performance computer architectures efficiently is challenging. In this paper the authors describe a massively parallel algorithm for solving the advection portion of the transport equation. We present an approach here which is different to that used in most transport models and which we have tried and tested for various scenarios. The approach employs an intelligent domain decomposition based on the vector field of the system equations and thus automatically partitions the computational domain into algorithmically autonomous regions. The solution of a classic pure advection transport problem is shown to be conservative, monotonic and highly accurate at large time steps. Additionally we demonstrate that the algorithm is highly efficient for high performance computer architectures and thus offers a route towards massively parallel application.

Manson, Russell [Richard Stockton College of New Jersey; Wang, Dali [ORNL

2010-01-01T23:59:59.000Z

24

MADmap: A Massively Parallel Maximum-Likelihood Cosmic Microwave Background Map-Maker  

SciTech Connect

MADmap is a software application used to produce maximum-likelihood images of the sky from time-ordered data which include correlated noise, such as those gathered by Cosmic Microwave Background (CMB) experiments. It works efficiently on platforms ranging from small workstations to the most massively parallel supercomputers. Map-making is a critical step in the analysis of all CMB data sets, and the maximum-likelihood approach is the most accurate and widely applicable algorithm; however, it is a computationally challenging task. This challenge will only increase with the next generation of ground-based, balloon-borne and satellite CMB polarization experiments. The faintness of the B-mode signal that these experiments seek to measure requires them to gather enormous data sets. MADmap is already being run on up to O(1011) time samples, O(108) pixels and O(104) cores, with ongoing work to scale to the next generation of data sets and supercomputers. We describe MADmap's algorithm based around a preconditioned conjugate gradient solver, fast Fourier transforms and sparse matrix operations. We highlight MADmap's ability to address problems typically encountered in the analysis of realistic CMB data sets and describe its application to simulations of the Planck and EBEX experiments. The massively parallel and distributed implementation is detailed and scaling complexities are given for the resources required. MADmap is capable of analysing the largest data sets now being collected on computing resources currently available, and we argue that, given Moore's Law, MADmap will be capable of reducing the most massive projected data sets.

Cantalupo, Christopher; Borrill, Julian; Jaffe, Andrew; Kisner, Theodore; Stompor, Radoslaw

2009-06-09T23:59:59.000Z

25

User's Guide for TOUGH2-MP - A Massively Parallel Version of the TOUGH2 Code  

Science Conference Proceedings (OSTI)

TOUGH2-MP is a massively parallel (MP) version of the TOUGH2 code, designed for computationally efficient parallel simulation of isothermal and nonisothermal flows of multicomponent, multiphase fluids in one, two, and three-dimensional porous and fractured media. In recent years, computational requirements have become increasingly intensive in large or highly nonlinear problems for applications in areas such as radioactive waste disposal, CO2 geological sequestration, environmental assessment and remediation, reservoir engineering, and groundwater hydrology. The primary objective of developing the parallel-simulation capability is to significantly improve the computational performance of the TOUGH2 family of codes. The particular goal for the parallel simulator is to achieve orders-of-magnitude improvement in computational time for models with ever-increasing complexity. TOUGH2-MP is designed to perform parallel simulation on multi-CPU computational platforms. An earlier version of TOUGH2-MP (V1.0) was based on the TOUGH2 Version 1.4 with EOS3, EOS9, and T2R3D modules, a software previously qualified for applications in the Yucca Mountain project, and was designed for execution on CRAY T3E and IBM SP supercomputers. The current version of TOUGH2-MP (V2.0) includes all fluid property modules of the standard version TOUGH2 V2.0. It provides computationally efficient capabilities using supercomputers, Linux clusters, or multi-core PCs, and also offers many user-friendly features. The parallel simulator inherits all process capabilities from V2.0 together with additional capabilities for handling fractured media from V1.4. This report provides a quick starting guide on how to set up and run the TOUGH2-MP program for users with a basic knowledge of running the (standard) version TOUGH2 code, The report also gives a brief technical description of the code, including a discussion of parallel methodology, code structure, as well as mathematical and numerical methods used. To familiarize users with the parallel code, illustrative sample problems are presented.

Earth Sciences Division; Zhang, Keni; Zhang, Keni; Wu, Yu-Shu; Pruess, Karsten

2008-05-27T23:59:59.000Z

26

3-D readout-electronics packaging for high-bandwidth massively paralleled imager  

DOE Patents (OSTI)

Dense, massively parallel signal processing electronics are co-packaged behind associated sensor pixels. Microchips containing a linear or bilinear arrangement of photo-sensors, together with associated complex electronics, are integrated into a simple 3-D structure (a "mirror cube"). An array of photo-sensitive cells are disposed on a stacked CMOS chip's surface at a 45.degree. angle from light reflecting mirror surfaces formed on a neighboring CMOS chip surface. Image processing electronics are held within the stacked CMOS chip layers. Electrical connections couple each of said stacked CMOS chip layers and a distribution grid, the connections for distributing power and signals to components associated with each stacked CSMO chip layer.

Kwiatkowski, Kris (Los Alamos, NM); Lyke, James (Albuquerque, NM)

2007-12-18T23:59:59.000Z

27

Climate system modeling on massively parallel systems: LDRD Project 95-ERP-47 final report  

Science Conference Proceedings (OSTI)

Global warming, acid rain, ozone depletion, and biodiversity loss are some of the major climate-related issues presently being addressed by climate and environmental scientists. Because unexpected changes in the climate could have significant effect on our economy, it is vitally important to improve the scientific basis for understanding and predicting the earth`s climate. The impracticality of modeling the earth experimentally in the laboratory together with the fact that the model equations are highly nonlinear has created a unique and vital role for computer-based climate experiments. However, today`s computer models, when run at desired spatial and temporal resolution and physical complexity, severely overtax the capabilities of our most powerful computers. Parallel processing offers significant potential for attaining increased performance and making tractable simulations that cannot be performed today. The principal goals of this project have been to develop and demonstrate the capability to perform large-scale climate simulations on high-performance computing systems (using methodology that scales to the systems of tomorrow), and to carry out leading-edge scientific calculations using parallelized models. The demonstration platform for these studies has been the 256-processor Cray-T3D located at Lawrence Livermore National Laboratory. Our plan was to undertake an ambitious program in optimization, proof-of-principle and scientific study. These goals have been met. We are now regularly using massively parallel processors for scientific study of the ocean and atmosphere, and preliminary parallel coupled ocean/atmosphere calculations are being carried out as well. Furthermore, our work suggests that it should be possible to develop an advanced comprehensive climate system model with performance scalable to the teraflops range. 9 refs., 3 figs.

Mirin, A.A.; Dannevik, W.P.; Chan, B.; Duffy, P.B.; Eltgroth, P.G.; Wehner, M.F.

1996-12-01T23:59:59.000Z

28

Measures of effectiveness for BMD mid-course tracking on MIMD massively parallel computers  

SciTech Connect

The TRC code, a mid-course tracking code for ballistic missiles, has previously been implemented on a 1024-processor MIMD (Multiple Instruction -- Multiple Data) massively parallel computer. Measures of Effectiveness (MOE) for this algorithm have been developed for this computing environment. The MOE code is run in parallel with the TRC code. Particularly useful MOEs include the number of missed objects (real objects for which the TRC algorithm did not construct a track); of ghost tracks (tracks not corresponding to a real object); of redundant tracks (multiple tracks corresponding to a single real object); and of unresolved objects (multiple objects corresponding to a single track). All of these are expressed as a function of time, and tend to maximize during the time in which real objects are spawned (multiple reentry vehicles per post-boost vehicle). As well, it is possible to measure the track-truth separation as a function of time. A set of calculations is presented illustrating these MOEs as a function of time for a case with 99 post-boost vehicles, each of which spawns 9 reentry vehicles.

VanDyke, J.P.; Tomkins, J.L.; Furnish, M.D.

1995-05-01T23:59:59.000Z

29

Software Project Management and Quality Engineering Practices for Complex, Coupled Multiphysics, Massively Parallel Computational Simulations: Lessons Learned From ASCI  

Science Conference Proceedings (OSTI)

Many institutions are now developing large-scale, complex, coupled multiphysics computational simulations for massively parallel platforms for the simulation of the performance of nuclear weapons and certification of the stockpile, and for research in ... Keywords: Software engineering, computational science, management, software project, validation, verification

D. E. Post; R. P. Kendall

2004-11-01T23:59:59.000Z

30

A comparison of CPUs, GPUs, FPGAs, and massively parallel processor arrays for random number generation  

Science Conference Proceedings (OSTI)

The future of high-performance computing is likely to rely on the ability to efficiently exploit huge amounts of parallelism. One way of taking advantage of this parallelism is to formulate problems as "embarrassingly parallel" Monte-Carlo simulations, ... Keywords: fpga, gpu, monte-carlo, mppa, random numbers

David Barrie Thomas; Lee Howes; Wayne Luk

2009-02-01T23:59:59.000Z

31

Mutations causing medullary cystic kidney disease type 1 lie in a large VNTR in MUC1 missed by massively parallel sequencing  

E-Print Network (OSTI)

Although genetic lesions responsible for some mendelian disorders can be rapidly discovered through massively parallel sequencing of whole genomes or exomes, not all diseases readily yield to such efforts. We describe the ...

Kirby, Andrew

32

Massively parallel direct numerical simulations of forced compressible turbulence: a hybrid MPI/OpenMP approach  

Science Conference Proceedings (OSTI)

A highly scalable simulation code for turbulent flows which solves the fully compressible Navier-Stokes equations is presented. The code, which supports one, two and three dimensional domain decompositions is shown to scale well on up to 262,144 cores. ... Keywords: direct numerical simulations, multilevel parallelism, parallel performance, turbulent flows

Shriram Jagannathan; Diego A. Donzis

2012-07-01T23:59:59.000Z

33

Xetal-II: A Low-Power Massively-Parallel Processor for Video Scene Analysis  

Science Conference Proceedings (OSTI)

A processor architecture combining high-performance and low-power is presented. A prototype chip, Xetal-II, has been realized in 90 nm CMOS technology based on the proposed architecture. Recent experimental results show a compute performance of up to ... Keywords: Low-power VLSI, Parallel processing, Processor tile, SIMD, Smart cameras, Video scene analysis

Anteneh A. Abbo; Richard P. Kleihorst; Ben Schueler

2011-01-01T23:59:59.000Z

34

Massively parallel solution of the inverse scattering problem for integrated circuit quality control  

Science Conference Proceedings (OSTI)

The authors developed and implemented a highly parallel computational algorithm for solution of the inverse scattering problem generated when an integrated circuit is illuminated by laser. The method was used as part of a system to measure diffraction grating line widths on specially fabricated test wafers and the results of the computational analysis were compared with more traditional line-width measurement techniques. The authors found they were able to measure the line width of singly periodic and doubly periodic diffraction gratings (i.e. 2D and 3D gratings respectively) with accuracy comparable to the best available experimental techniques. They demonstrated that their parallel code is highly scalable, achieving a scaled parallel efficiency of 90% or more on typical problems running on 1024 processors. They also made substantial improvements to the algorithmics and their original implementation of Rigorous Coupled Waveform Analysis, the underlying computational technique. These resulted in computational speed-ups of two orders of magnitude in some test problems. By combining these algorithmic improvements with parallelism the authors achieve speedups of between a few thousand and hundreds of thousands over the original engineering code. This made the laser diffraction measurement technique practical.

Leland, R.W.; Draper, B.L. [Sandia National Labs., NM (United States); Naqvi, S.; Minhas, B. [Univ. of New Mexico, Albuquerque, NM (United States). Electrical Engineering and Computer Sciences Dept.

1997-09-01T23:59:59.000Z

35

Space-charge-dominated beam dynamics simulations using the massively parallel processors (MPPs) of the Cray T3D  

Science Conference Proceedings (OSTI)

Computer simulations using the multi-particle code PARMELA with a three-dimensional point-by-point space charge algorithm have turned out to be very helpful in supporting injector commissioning and operations at Thomas Jefferson National Accelerator Facility (Jefferson Lab, formerly called CEBAF). However, this algorithm, which defines a typical N{sup 2} problem in CPU time scaling, is very time-consuming when N, the number of macro-particles, is large. Therefore, it is attractive to use massively parallel processors (MPPs) to speed up the simulations. Motivated by this, the authors modified the space charge subroutine for using the MPPs of the Cray T3D. The techniques used to parallelize and optimize the code on the T3D are discussed in this paper. The performance of the code on the T3D is examined in comparison with a Parallel Vector Processing supercomputer of the Cray C90 and an HP 735/15 high-end workstation.

Liu, H.

1996-10-01T23:59:59.000Z

36

Analysis and selection of optimal function implementations in massively parallel computer  

DOE Patents (OSTI)

An apparatus, program product and method optimize the operation of a parallel computer system by, in part, collecting performance data for a set of implementations of a function capable of being executed on the parallel computer system based upon the execution of the set of implementations under varying input parameters in a plurality of input dimensions. The collected performance data may be used to generate selection program code that is configured to call selected implementations of the function in response to a call to the function under varying input parameters. The collected performance data may be used to perform more detailed analysis to ascertain the comparative performance of the set of implementations of the function under the varying input parameters.

Archer, Charles Jens (Rochester, MN); Peters, Amanda (Rochester, MN); Ratterman, Joseph D. (Rochester, MN)

2011-05-31T23:59:59.000Z

37

Massively-parallel electrical-conductivity imaging of hydrocarbonsusing the Blue Gene/L supercomputer  

Science Conference Proceedings (OSTI)

Large-scale controlled source electromagnetic (CSEM)three-dimensional (3D) geophysical imaging is now receiving considerableattention for electrical conductivity mapping of potential offshore oiland gas reservoirs. To cope with the typically large computationalrequirements of the 3D CSEM imaging problem, our strategies exploitcomputational parallelism and optimized finite-difference meshing. Wereport on an imaging experiment, utilizing 32,768 tasks/processors on theIBM Watson Research Blue Gene/L (BG/L) supercomputer. Over a 24-hourperiod, we were able to image a large scale marine CSEM field data setthat previously required over four months of computing time ondistributed clusters utilizing 1024 tasks on an Infiniband fabric. Thetotal initial data misfit could be decreased by 67 percent within 72completed inversion iterations, indicating an electrically resistiveregion in the southern survey area below a depth of 1500 m below theseafloor. The major part of the residual misfit stems from transmitterparallel receiver components that have an offset from the transmittersail line (broadside configuration). Modeling confirms that improvedbroadside data fits can be achieved by considering anisotropic electricalconductivities. While delivering a satisfactory gross scale image for thedepths of interest, the experiment provides important evidence for thenecessity of discriminating between horizontal and verticalconductivities for maximally consistent 3D CSEM inversions.

Commer, M.; Newman, G.A.; Carazzone, J.J.; Dickens, T.A.; Green,K.E.; Wahrmund, L.A.; Willen, D.E.; Shiu, J.

2007-05-16T23:59:59.000Z

38

Massively parallel rRNA gene sequencing exacerbates the potential for biased community diversity comparisons due to variable library sizes  

Science Conference Proceedings (OSTI)

Technologies for massively parallel sequencing are revolutionizing microbial ecology and are vastly increasing the scale of ribosomal RNA (rRNA) gene studies. Although pyrosequencing has increased the breadth and depth of possible rRNA gene sampling, one drawback is that the number of reads obtained per sample is difficult to control. Pyrosequencing libraries typically vary widely in the number of sequences per sample, even within individual studies, and there is a need to revisit the behaviour of richness estimators and diversity indices with variable gene sequence library sizes. Multiple reports and review papers have demonstrated the bias in non-parametric richness estimators (e.g. Chao1 and ACE) and diversity indices when using clone libraries. However, we found that biased community comparisons are accumulating in the literature. Here we demonstrate the effects of sample size on Chao1, ACE, CatchAll, Shannon, Chao-Shen and Simpson's estimations specifically using pyrosequencing libraries. The need to equalize the number of reads being compared across libraries is reiterated, and investigators are directed towards available tools for making unbiased diversity comparisons.

Gihring, Thomas [ORNL; Green, Stefan [Florida State University; Schadt, Christopher Warren [ORNL

2011-01-01T23:59:59.000Z

39

Parallelizing  

NLE Websites -- All DOE Office Websites (Extended Search)

scripting languages, such as Bash, and then exe- cute them in-memory on large-scale computers. We define a small set of commands between the scripts and a parallel scripting...

40

Method and apparatus for routing data in an inter-nodal communications lattice of a massively parallel computer system by dynamic global mapping of contended links  

DOE Patents (OSTI)

A massively parallel nodal computer system periodically collects and broadcasts usage data for an internal communications network. A node sending data over the network makes a global routing determination using the network usage data. Preferably, network usage data comprises an N-bit usage value for each output buffer associated with a network link. An optimum routing is determined by summing the N-bit values associated with each link through which a data packet must pass, and comparing the sums associated with different possible routes.

Archer, Charles Jens (Rochester, MN); Musselman, Roy Glenn (Rochester, MN); Peters, Amanda (Rochester, MN); Pinnow, Kurt Walter (Rochester, MN); Swartz, Brent Allen (Chippewa Falls, WI); Wallenfelt, Brian Paul (Eden Prairie, MN)

2011-10-04T23:59:59.000Z

Note: This page contains sample records for the topic "massively parallel microcell-based" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Partition-of-unity finite-element method for large scale quantum molecular dynamics on massively parallel computational platforms  

Science Conference Proceedings (OSTI)

Over the course of the past two decades, quantum mechanical calculations have emerged as a key component of modern materials research. However, the solution of the required quantum mechanical equations is a formidable task and this has severely limited the range of materials systems which can be investigated by such accurate, quantum mechanical means. The current state of the art for large-scale quantum simulations is the planewave (PW) method, as implemented in now ubiquitous VASP, ABINIT, and QBox codes, among many others. However, since the PW method uses a global Fourier basis, with strictly uniform resolution at all points in space, and in which every basis function overlaps every other at every point, it suffers from substantial inefficiencies in calculations involving atoms with localized states, such as first-row and transition-metal atoms, and requires substantial nonlocal communications in parallel implementations, placing critical limits on scalability. In recent years, real-space methods such as finite-differences (FD) and finite-elements (FE) have been developed to address these deficiencies by reformulating the required quantum mechanical equations in a strictly local representation. However, while addressing both resolution and parallel-communications problems, such local real-space approaches have been plagued by one key disadvantage relative to planewaves: excessive degrees of freedom (grid points, basis functions) needed to achieve the required accuracies. And so, despite critical limitations, the PW method remains the standard today. In this work, we show for the first time that this key remaining disadvantage of real-space methods can in fact be overcome: by building known atomic physics into the solution process using modern partition-of-unity (PU) techniques in finite element analysis. Indeed, our results show order-of-magnitude reductions in basis size relative to state-of-the-art planewave based methods. The method developed here is completely general, applicable to any crystal symmetry and to both metals and insulators alike. We have developed and implemented a full self-consistent Kohn-Sham method, including both total energies and forces for molecular dynamics, and developed a full MPI parallel implementation for large-scale calculations. We have applied the method to the gamut of physical systems, from simple insulating systems with light atoms to complex d- and f-electron systems, requiring large numbers of atomic-orbital enrichments. In every case, the new PU FE method attained the required accuracies with substantially fewer degrees of freedom, typically by an order of magnitude or more, than the current state-of-the-art PW method. Finally, our initial MPI implementation has shown excellent parallel scaling of the most time-critical parts of the code up to 1728 processors, with clear indications of what will be required to achieve comparable scaling for the rest. Having shown that the key remaining disadvantage of real-space methods can in fact be overcome, the work has attracted significant attention: with sixteen invited talks, both domestic and international, so far; two papers published and another in preparation; and three new university and/or national laboratory collaborations, securing external funding to pursue a number of related research directions. Having demonstrated the proof of principle, work now centers on the necessary extensions and optimizations required to bring the prototype method and code delivered here to production applications.

Pask, J E; Sukumar, N; Guney, M; Hu, W

2011-02-28T23:59:59.000Z

42

Scientific development of a massively parallel ocean climate model. Progress report for 1992--1993 and Continuing request for 1993--1994 to CHAMMP (Computer Hardware, Advanced Mathematics, and Model Physics)  

SciTech Connect

During the second year of CHAMMP funding to the principal investigators, progress has been made in the proposed areas of research, as follows: investigation of the physics of the thermohaline circulation; examination of resolution effects on ocean general circulation; and development of a massively parallel ocean climate model.

Semtner, A.J. Jr. [Naval Postgraduate School, Monterey, CA (United States); Chervin, R.M. [National Center for Atmospheric Research, Boulder, CO (United States)

1993-05-01T23:59:59.000Z

43

Parallel Index  

NLE Websites -- All DOE Office Websites (Extended Search)

Parallel Parallel Index and Query for Large Scale Data Analysis Jerry Chou Kesheng Wu Oliver Rübel Mark Howison Ji Qiang Prabhat Brian Austin E. Wes Bethel Rob D. Ryne Arie Shoshani ABSTRACT Modern scientific datasets present numerous data manage- ment and analysis challenges. State-of-the-art index and query technologies are critical for facilitating interactive ex- ploration of large datasets, but numerous challenges remain in terms of designing a system for processing general scien- tific datasets. The system needs to be able to run on dis- tributed multi-core platforms, efficiently utilize underlying I/O infrastructure, and scale to massive datasets. We present FastQuery, a novel software framework that address these challenges. FastQuery utilizes a state-of-the- art index and query technology (FastBit) and is designed to process massive datasets on modern supercomputing

44

Massive Gravity  

E-Print Network (OSTI)

We review recent progress in massive gravity. We start by showing how different theories of massive gravity emerge from a higher-dimensional theory of general relativity, leading to the Dvali-Gabadadze-Porrati model, cascading gravity and ghost-free massive gravity. We then explore their theoretical and phenomenological consistency, proving the absence of Boulware-Deser ghosts and reviewing the Vainshtein mechanism and the cosmological solutions in these models. Finally we present alternative and related models of massive gravity such as new massive gravity, Lorentz-violating massive gravity and non-local massive gravity.

de Rham, Claudia

2014-01-01T23:59:59.000Z

45

Massive Gravity  

E-Print Network (OSTI)

We review recent progress in massive gravity. We start by showing how different theories of massive gravity emerge from a higher-dimensional theory of general relativity, leading to the Dvali-Gabadadze-Porrati model, cascading gravity and ghost-free massive gravity. We then explore their theoretical and phenomenological consistency, proving the absence of Boulware-Deser ghosts and reviewing the Vainshtein mechanism and the cosmological solutions in these models. Finally we present alternative and related models of massive gravity such as new massive gravity, Lorentz-violating massive gravity and non-local massive gravity.

Claudia de Rham

2014-01-16T23:59:59.000Z

46

Adaptively parallelizing distributed range queries  

Science Conference Proceedings (OSTI)

We consider the problem of how to best parallelize range queries in a massive scale distributed database. In traditional systems the focus has been on maximizing parallelism, for example by laying out data to achieve the highest throughput. However, ...

Ymir Vigfusson; Adam Silberstein; Brian F. Cooper; Rodrigo Fonseca

2009-08-01T23:59:59.000Z

47

Parallel computing works  

Science Conference Proceedings (OSTI)

An account of the Caltech Concurrent Computation Program (C{sup 3}P), a five year project that focused on answering the question: Can parallel computers be used to do large-scale scientific computations '' As the title indicates, the question is answered in the affirmative, by implementing numerous scientific applications on real parallel computers and doing computations that produced new scientific results. In the process of doing so, C{sup 3}P helped design and build several new computers, designed and implemented basic system software, developed algorithms for frequently used mathematical computations on massively parallel machines, devised performance models and measured the performance of many computers, and created a high performance computing facility based exclusively on parallel computers. While the initial focus of C{sup 3}P was the hypercube architecture developed by C. Seitz, many of the methods developed and lessons learned have been applied successfully on other massively parallel architectures.

Not Available

1991-10-23T23:59:59.000Z

48

A Task Parallel Implementation of Fast Multipole Methods  

Science Conference Proceedings (OSTI)

This paper describes a task parallel implementation of ExaFMM, an open source implementation of fast multipole methods (FMM), using a lightweight task parallel library MassiveThreads. Although there have been many attempts on parallelizing FMM, experiences ... Keywords: task parallelism, fast multipole methods, FMM, divide and conquer, MassiveThreads, ExaFMM

Kenjiro Taura, Jun Nakashima, Rio Yokota, Naoya Maruyama

2012-11-01T23:59:59.000Z

49

High-speed massively parallel scanning  

DOE Patents (OSTI)

A new technique for recording a series of images of a high-speed event (such as, but not limited to: ballistics, explosives, laser induced changes in materials, etc.) is presented. Such technique(s) makes use of a lenslet array to take image picture elements (pixels) and concentrate light from each pixel into a spot that is much smaller than the pixel. This array of spots illuminates a detector region (e.g., film, as one embodiment) which is scanned transverse to the light, creating tracks of exposed regions. Each track is a time history of the light intensity for a single pixel. By appropriately configuring the array of concentrated spots with respect to the scanning direction of the detection material, different tracks fit between pixels and sufficient lengths are possible which can be of interest in several high-speed imaging applications.

Decker, Derek E. (Byron, CA)

2010-07-06T23:59:59.000Z

50

Massively parallel X-ray scattering simulations  

Science Conference Proceedings (OSTI)

Although present X-ray scattering techniques can provide tremendous information on the nano-structural properties of materials that are valuable in the design and fabrication of energy-relevant nano-devices, a primary challenge remains in the analyses ...

Abhinav Sarje; Xiaoye S. Li; Slim Chourou; Elaine R. Chan; Alexander Hexemer

2012-11-01T23:59:59.000Z

51

Massively Parallel Simulations of Materials Response  

Science Conference Proceedings (OSTI)

Atomic Scale Deformation Mechanisms of Amorphous Polyethylene under Tensile Loading · Atomistic Predictions of Age Hardening in Al-Cu Alloys.

52

Massively parallelizing the RRT and the RRT*  

E-Print Network (OSTI)

In recent years, the growth of the computational power available in the Central Processing Units (CPUs) of consumer computers has tapered significantly. At the same time, growth in the computational power available in the ...

Karaman, Sertac

53

Parallel implementation of a semidefinite programming solver based ...  

E-Print Network (OSTI)

Mar 5, 2008 ... A beta version of our software is freely available at ... and software in recent years have helped to level the field between massively parallel ...

54

High Performance Computing: From Grids and Clouds to Exascale Volume 20 Advances in Parallel Computing  

Science Conference Proceedings (OSTI)

In the last decade, parallel computing technologies have transformed highperformance computing. Two trends have emerged: massively parallel computing leading to exascale on the one hand and moderately parallel applications, which have opened up highperformance ...

I. Foster; W. Gentzsch; L. Grandinetti; G. R. Joubert

2011-09-01T23:59:59.000Z

55

Ultrascalable petaflop parallel supercomputer  

DOE Patents (OSTI)

A massively parallel supercomputer of petaOPS-scale includes node architectures based upon System-On-a-Chip technology, where each processing node comprises a single Application Specific Integrated Circuit (ASIC) having up to four processing elements. The ASIC nodes are interconnected by multiple independent networks that optimally maximize the throughput of packet communications between nodes with minimal latency. The multiple networks may include three high-speed networks for parallel algorithm message passing including a Torus, collective network, and a Global Asynchronous network that provides global barrier and notification functions. These multiple independent networks may be collaboratively or independently utilized according to the needs or phases of an algorithm for optimizing algorithm processing performance. The use of a DMA engine is provided to facilitate message passing among the nodes without the expenditure of processing resources at the node.

Blumrich, Matthias A. (Ridgefield, CT); Chen, Dong (Croton On Hudson, NY); Chiu, George (Cross River, NY); Cipolla, Thomas M. (Katonah, NY); Coteus, Paul W. (Yorktown Heights, NY); Gara, Alan G. (Mount Kisco, NY); Giampapa, Mark E. (Irvington, NY); Hall, Shawn (Pleasantville, NY); Haring, Rudolf A. (Cortlandt Manor, NY); Heidelberger, Philip (Cortlandt Manor, NY); Kopcsay, Gerard V. (Yorktown Heights, NY); Ohmacht, Martin (Yorktown Heights, NY); Salapura, Valentina (Chappaqua, NY); Sugavanam, Krishnan (Mahopac, NY); Takken, Todd (Brewster, NY)

2010-07-20T23:59:59.000Z

56

Parallel cities  

Science Conference Proceedings (OSTI)

In this paper we introduce the concept of Parallel Cities---live, 3D simulations of actual cities kept "true to life" using real-time information from their real-world counterparts. A key enabler of the concept is the ever-growing tide of SNS ... Keywords: Twitter, city simulation, parallel city, social networking services, urban sensing

Yuichiro Takeuchi

2013-10-01T23:59:59.000Z

57

A Parallel Multigrid Method for Neutronics Applications  

Science Conference Proceedings (OSTI)

The multigrid method has been shown to be the most effective general method for solving the multi-dimensional diffusion equation encountered in neutronics. This being the method of choice, we develop a strategy for implementing the multigrid method on computers of massively parallel architecture. This leads us to strategies for parallelizing the relaxation, contraction (interpolation), and prolongation operators involved in the method. We then compare the efficiency of our parallel multigrid with other parallel methods for solving the diffusion equation on selected problems encountered in reactor physics.

Alcouffe, Raymond E.

2001-01-01T23:59:59.000Z

58

On Massively Parallel Algorithm for Nonlinear Stochastic Network Problems  

E-Print Network (OSTI)

We develop an algorithm for solving nonlinear two-stage stochastic problems with network recourse. The algorithm is based on the framework of row-action methods. The problem is formulated by replicating the first-stage ...

Nielson, Soren S.

59

Bigravity and Massive Gravity  

Science Conference Proceedings (OSTI)

We discuss some issues concerning the global structure of spherically symmetric solutions of bigravity. We propose maximal extensions of manifolds where two causal structure coexist. Besides we make some comments about the perturbations of these solutions and their relation to massive gravity and the cosmological constant problem.

D. Blas

2006-01-01T23:59:59.000Z

60

Parallel TreeSPH  

E-Print Network (OSTI)

We describe PTreeSPH, a gravity treecode combined with an SPH hydrodynamics code designed for massively parallel supercomputers having distributed memory. Our computational algorithm is based on the popular TreeSPH code of Hernquist & Katz (1989). PTreeSPH utilizes a domain decomposition procedure and a synchronous hypercube communication paradigm to build self-contained subvolumes of the simulation on each processor at every timestep. Computations then proceed in a manner analogous to a serial code. We use the Message Passing Interface (MPI) communications package, making our code easily portable to a variety of parallel systems. PTreeSPH uses individual smoothing lengths and timesteps, with a communication algorithm designed to minimize exchange of information while still providing all information required to accurately perform SPH computations. We have additionally incorporated cosmology, periodic boundary conditions with forces calculated using a quadrupole Ewald summation method, and radiative cooling and heating from a parameterized ionizing background following Katz, Weinberg & Hernquist (1996). The addition of other physical processes, such as star formation, is straightforward. A cosmological simulation from z=49 to z=2 with 64^3 gas particles and 64^3 dark matter particles requires ~6000 node-hours on a Cray T3D, with a communications overhead of ~10% and is load balanced to a ~90% level. When used on the new Cray T3E, this code will be capable of performing cosmological hydrodynamical simulations down to z=0 with ~2x10^6 particles, or to z=2 with ~10^7 particles, in a reasonable amount of time. Even larger simulations will be practical in situations where the matter is not highly clustered or when periodic boundaries are not required.

Romeel Dave'; John Dubinski; Lars Hernquist

1997-01-17T23:59:59.000Z

Note: This page contains sample records for the topic "massively parallel microcell-based" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Massive-Conformal Dictionary  

E-Print Network (OSTI)

The finite-volume spectrum of an integrable massive perturbation of a rational conformal field theory interpolates between massive multi-particle states in infinite volume (IR limit) and conformal states, which are approached at zero volume (UV limit). Each state is labeled in the IR by a set of `Bethe Ansatz quantum numbers', while in the UV limit it is characterized primarily by the conformal dimensions of the conformal field creating it. We present explicit conjectures for the UV conformal dimensions corresponding to any IR state in the $\\phi_{1,3}$-perturbed minimal models $M(2,5)$ and $M(3,5)$. The conjectures, which are based on a combinatorial interpretation of the Rogers-Ramanujan-Schur identities, are consistent with numerical results obtained previously for low-lying energy levels.

Ezer Melzer

1993-11-10T23:59:59.000Z

62

Strong scaling analysis of a parallel, unstructured, implicit solver and the influence of the operating system interference  

Science Conference Proceedings (OSTI)

PHASTA falls under the category of high-performance scientific computation codes designed for solving partial differential equations (PDEs). Its a massively parallel unstructured, implicit solver with particular emphasis on fluid dynamics (CFD) applications. ... Keywords: OS jitter, Strong scaling, massively parallel processing, unstructured and implicit methods

Onkar Sahni; Christopher D. Carothers; Mark S. Shephard; Kenneth E. Jansen

2009-08-01T23:59:59.000Z

63

Scalable isosurface visualization of massive datasets on commodity off-the-shelf clusters  

Science Conference Proceedings (OSTI)

Tomographic imaging and computer simulations are increasingly yielding massive datasets. Interactive and exploratory visualizations have rapidly become indispensable tools to study large volumetric imaging and simulation data. Our scalable isosurface ... Keywords: Metabuffer, Multi-resolution, Parallel and out-of-core isocontouring, Parallel rendering, Progressive mesh

Xiaoyu Zhang; Chandrajit Bajaj

2009-01-01T23:59:59.000Z

64

Massive June Bug Emergence  

NLE Websites -- All DOE Office Websites (Extended Search)

Massive June Bug Emergence Massive June Bug Emergence Name: Cordell Location: N/A Country: N/A Date: N/A Question: We are infested with june bugs next to the street light near the end of my driveway. They have burrowed into the ground and underneath my driveway. Yesterday we shoveled 2/3 of a 33-gallon trash bag of just bugs. What can we spray or do to kill these june bugs? Replies: Not knowing which part of the country you are from and I could be wrong because of this fact buy this does not sound like June Bugs. This has to be a Circadia outbreak which are relatives to the June Bug. They run in 13, 17 or other year cycles and this depends upon the part of the country you are from. Ask a local garden center or naturalist and you'll probably see that this won't happen again for a number of years to come.

65

The NAS Parallel Benchmarks  

E-Print Network (OSTI)

Weeratunga, “The NAS Parallel Benchmarks,” Intl. Journal ofD. Simon, “NAS Par- allel Benchmark Results,” Proceedings ofD. Simon, “NAS Par- allel Benchmark Results,” IEEE Parallel

Bailey, David H.

2010-01-01T23:59:59.000Z

66

Elegant Parallelization Progress Report  

NLE Websites -- All DOE Office Websites (Extended Search)

Elegant Parallelization Progress Report 102407 Yusong Wang Michael Borland Hairong Shang Robert Soliday Elegant Parallelization Progress Report Y. Wang, 102407 Simulations with...

67

Simplified parallel domain traversal  

Science Conference Proceedings (OSTI)

Many data-intensive scientific analysis techniques require global domain traversal, which over the years has been a bottleneck for efficient parallelization across distributed-memory architectures. Inspired by MapReduce and other simplified parallel ... Keywords: atmospheric ensemble analysis, data-intensive analysis, parallel particle tracing, parallel processing

Wesley Kendall; Jingyuan Wang; Melissa Allen; Tom Peterka; Jian Huang; David Erickson

2011-11-01T23:59:59.000Z

68

Entanglement in massive coupled oscillators  

Science Conference Proceedings (OSTI)

This article investigates entanglement of the motional states of massive coupled oscillators.The specific realization of an idealized diatomic molecule in one-dimension isconsidered, but the techniques developed apply to any massive particles with two ... Keywords: closed-system entanglement dynamics, continuous-variable entanglement, coupled oscillators

Nathan L. Harshman; William F. Flynn

2011-03-01T23:59:59.000Z

69

Parallel Batch Scripts  

NLE Websites -- All DOE Office Websites (Extended Search)

Parallel Batch Scripts Parallel Batch Scripts Parallel Batch Scripts Parallel Environments on Genepool You can run parallel jobs that use MPI or OpenMP on Genepool as long as you make the appropriate changes to your submission script! To investigate the parallel environments that are available on Genepool, you can use Command Description qconf -sp Show the configuration for the specified parallel environment. qconf -spl Show a list of all currently configured parallel environments. Basic Parallel Example If your job requires the default 5GB of memory per slot, you can do the following: #!/bin/bash # # == Set SGE options: # # -- ensure BASH is used # -- run the job in the current working directory (where qsub is called) #$ -cwd # -- run with the environment variables from the User's environment

70

Efficient event-driven simulation of parallel processor architectures  

Science Conference Proceedings (OSTI)

In this paper we present a new approach for generating high-speed optimized event-driven instruction set level simulators for adaptive massively parallel processor architectures. The simulator generator is part of a methodology for the systematic mapping, ... Keywords: embedded tools, modeling, processor arrays, simulation

Alexey Kupriyanov; Dmitrij Kissler; Frank Hannig; Jürgen Teich

2007-04-01T23:59:59.000Z

71

Nested parallelism for multi-core HPC systems using Java  

Science Conference Proceedings (OSTI)

Since its introduction in 1993, the Message Passing Interface (MPI) has become a de facto standard for writing High Performance Computing (HPC) applications on clusters and Massively Parallel Processors (MPPs). The recent emergence of multi-core processor ... Keywords: Java MPI, MPJ, MPJ express, Multi-core messaging

Aamir Shafi; Bryan Carpenter; Mark Baker

2009-06-01T23:59:59.000Z

72

The IXM2 Parallel Associative Processor for AI  

Science Conference Proceedings (OSTI)

Describes the IXM2 associative processor and its main application in speech-to-speech translation. The IXM2 is a semantic memory system machine that began as a faithful implementation of the NETL semantic network machine and grew into a massively parallel ...

Tetsuya Higuchi; Kennichi Handa; Naoto Takahashi; Tatsumi Furuya; Hitoshi Iida; Eiishiro Sumita; Kozo Oi; Hiroaki Kitano

1994-11-01T23:59:59.000Z

73

Parallel flow diffusion battery  

DOE Patents (OSTI)

A parallel flow diffusion battery for determining the mass distribution of an aerosol has a plurality of diffusion cells mounted in parallel to an aerosol stream, each diffusion cell including a stack of mesh wire screens of different density.

Yeh, Hsu-Chi (Albuquerque, NM); Cheng, Yung-Sung (Albuquerque, NM)

1984-08-07T23:59:59.000Z

74

Parallel flow diffusion battery  

DOE Patents (OSTI)

A parallel flow diffusion battery for determining the mass distribution of an aerosol has a plurality of diffusion cells mounted in parallel to an aerosol stream, each diffusion cell including a stack of mesh wire screens of different density.

Yeh, H.C.; Cheng, Y.S.

1984-01-01T23:59:59.000Z

75

A parallel implementation of Strassen's matrix multiplication algorithm for wormhole-routed all-port 2D torus networks  

Science Conference Proceedings (OSTI)

A new parallel implementation of Strassen's matrix multiplication algorithm is proposed for massively parallel supercomputers with 2D, all-port torus interconnection networks. The proposed algorithm employs a special conflict-free routing pattern for ... Keywords: 2D torus, Fast Matrix Multiplication, Parallel processing, Strassen's matrix multiplication, Torus interconnection networks

Cesur Baransel; Kayhan M. ?mre

2012-10-01T23:59:59.000Z

76

Massive gravity from bimetric gravity  

E-Print Network (OSTI)

We discuss the subtle relationship between so-called massive gravity (that is, gravity incorporating a non-zero graviton mass) and bimetric gravity, focussing particularly on the manner in which massive gravity may be viewed as a suitable limit of bimetric gravity. The limiting procedure is more delicate than currently appreciated, and in particular, in a cosmological context can lead to an interesting interplay between the "background" and "foreground" metrics. The fact that in bimetric theories one always has two sets of metric equations of motion, one for each metric, continues to have an effect even in the massive gravity limit. Thus, solutions of bimetric gravity in the limit of vanishing kinetic term are also solutions of massive gravity, but the contrary statement is not necessarily true.

Baccetti, Valentina; Visser, Matt

2012-01-01T23:59:59.000Z

77

SMI 2011: Full Paper: Parallel computation of spherical parameterizations for mesh analysis  

Science Conference Proceedings (OSTI)

Mesh parameterization is central to a broad spectrum of applications. In this paper, we present a novel approach to spherical mesh parameterization based on an iterative quadratic solver that is efficiently parallelizable on modern massively parallel ... Keywords: Feature detection, GPU, Mesh parameterization, Mesh segmentation, Parallel algorithms, Shape similarity object retrieval

Theodoros Athanasiadis; Ioannis Fudos

2011-06-01T23:59:59.000Z

78

Thought Leaders during Crises in Massive Social Networks  

SciTech Connect

The vast amount of social media data that can be gathered from the internet coupled with workflows that utilize both commodity systems and massively parallel supercomputers, such as the Cray XMT, open new vistas for research to support health, defense, and national security. Computer technology now enables the analysis of graph structures containing more than 4 billion vertices joined by 34 billion edges along with metrics and massively parallel algorithms that exhibit near-linear scalability according to number of processors. The challenge lies in making this massive data and analysis comprehensible to an analyst and end-users that require actionable knowledge to carry out their duties. Simply stated, we have developed language and content agnostic techniques to reduce large graphs built from vast media corpora into forms people can understand. Specifically, our tools and metrics act as a survey tool to identify thought leaders' -- those members that lead or reflect the thoughts and opinions of an online community, independent of the source language.

Corley, Courtney D.; Farber, Robert M.; Reynolds, William

2012-05-24T23:59:59.000Z

79

Multi-Flip Networks: Extending Symmetric Networks to Real Parallelism  

E-Print Network (OSTI)

In general, neural networks are regarded as models for massively parallel computation. But very often, this parallelism is rather limited, especially when considering symmetric networks. For instance, Hopfield networks do not really compute in parallel as their updating algorithm always requires sequential execution. Nevertheless, Hopfield networks can be used as auto-associative memories, were shown to have an expressive power equivalent to propositional logic, and can be used to solve several combinatorial problems. Extensions like the Boltzmann Machine with continuous activation functions can additionally be used to solve optimization problems. But, all of these approaches suffer from one disadvantage, namely the impossibility to perform simultaneous computations of more than one unit, i.e. real parallelism. We describe a recurrent network corresponding to a symmetric network and introduce a method of parallel updating multiple units. We show how this may be extended to ...

Antje Strohmaier; Fachgebiet Intellektik; Fachbereich Informatik; Technische Hochschule Darmstadt

1996-01-01T23:59:59.000Z

80

Parallel digital forensics infrastructure.  

Science Conference Proceedings (OSTI)

This report documents the architecture and implementation of a Parallel Digital Forensics infrastructure. This infrastructure is necessary for supporting the design, implementation, and testing of new classes of parallel digital forensics tools. Digital Forensics has become extremely difficult with data sets of one terabyte and larger. The only way to overcome the processing time of these large sets is to identify and develop new parallel algorithms for performing the analysis. To support algorithm research, a flexible base infrastructure is required. A candidate architecture for this base infrastructure was designed, instantiated, and tested by this project, in collaboration with New Mexico Tech. Previous infrastructures were not designed and built specifically for the development and testing of parallel algorithms. With the size of forensics data sets only expected to increase significantly, this type of infrastructure support is necessary for continued research in parallel digital forensics. This report documents the implementation of the parallel digital forensics (PDF) infrastructure architecture and implementation.

Liebrock, Lorie M. (New Mexico Tech, Socorro, NM); Duggan, David Patrick

2009-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "massively parallel microcell-based" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

A Stable Massive Charged Particle  

E-Print Network (OSTI)

We consider the possibility of the existence of a stable massive charged particle by a minimal extension of the standard model particle content. Absolute stability in the case of singly charged particle is not possible if the usual doublet Higgs exists, unless a discrete symmetry is imposed.But a doubly charged particle is absolutely stable.

G. Rajasekaran

2011-05-26T23:59:59.000Z

82

Clustering in massive data sets  

Science Conference Proceedings (OSTI)

We review the time and storage costs of search and clustering algorithms. We exemplify these, based on case-studies in astronomy, information retrieval, visual user interfaces, chemical databases, and other areas. Theoretical results developed as far ... Keywords: clustering, massive data sets

Fionn Murtagh

2002-01-01T23:59:59.000Z

83

Parallel speedup estimates for serial programs  

E-Print Network (OSTI)

Self-Parallelism (ESP) . . . . . . . . . .3.2.2 ParallelSelf-Parallelism (ESP) . 3.4.4 Impact of Parallelizationself-parallelism (ESP) to honor each parallelization

Jeon, Donghwan; Jeon, Donghwan

2012-01-01T23:59:59.000Z

84

Tightfit: adaptive parallelization with foresight  

Science Conference Proceedings (OSTI)

Irregular applications often exhibit data-dependent parallelism: Different inputs, and sometimes also different execution phases, enable different levels of parallelism. These changes in available parallelism have motivated work on adaptive concurrency ... Keywords: STM, adaptive software parallelization, data-dependent parallelism, irregular applications, offline learning

Omer Tripp; Noam Rinetzky

2013-08-01T23:59:59.000Z

85

Parallel and Distributed Haskells  

Science Conference Proceedings (OSTI)

Parallel and distributed languages specify computations on multiple processors and have a computation language to describe the algorithm, i.e. what to compute, and a coordination language to describe how to organise the computations across ...

P. W. Trinder; H.-W. Loidl; R. F. Pointon

2002-07-01T23:59:59.000Z

86

Manticore: a heterogeneous parallel language  

Science Conference Proceedings (OSTI)

The Manticore project is an effort to design and implement a new functional language for parallel programming. Unlike many earlier parallel languages, Manticore is a heterogeneous language that supports parallelism at multiple levels. Specifically, ...

Matthew Fluet; Mike Rainey; John Reppy; Adam Shaw; Yingqi Xiao

2007-01-01T23:59:59.000Z

87

RECIPIENT:Semprius  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Semprius Semprius u.s. DEPARTr-IEN T OF ENERGY EERE PROJECT MAN AGEMEN T CENT ER NEPA DETERMINATION Page 1 of2 STATE: NC PROJECT TITLE: SAl Incubator - Semprius - Massively Parallel Microcell-based Module Array; NREl Tracking No. 09- 036a Funding Opportunity Announcement Number Procur~mtnt Instrument Number NEPA Control Number elD Number NREL-09-036a G010337 Based on my review of the information concuning the proposed action, as Nf:PA Compliance Officer (authorized undcr DOE Order 45 I. IA), I have made the following determination: ex, EA, EIS APPENDIX ANI) NUMBER: Description: 83.6 Siting, construction (or modification), operation, and decommissioning of facilities for indoor bench-scale research projects and conventional laboratory operations (for example, preparation of chemical standards and sample analysis);

88

Categorical Exclusion Determinations: North Carolina | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

April 9, 2010 April 9, 2010 CX-001794: Categorical Exclusion Determination Commercial Renewable Energy Systems - Charlotte Mecklenburg School Solar Thermal CX(s) Applied: B5.1 Date: 04/09/2010 Location(s): Cornelius, North Carolina Office(s): Energy Efficiency and Renewable Energy, National Energy Technology Laboratory April 8, 2010 CX-001635: Categorical Exclusion Determination Solar American Institute Incubator - Semprius - Massively Parallel Microcell-Based Module Array CX(s) Applied: B3.6 Date: 04/08/2010 Location(s): Durham, North Carolina Office(s): Energy Efficiency and Renewable Energy, Golden Field Office April 7, 2010 CX-001432: Categorical Exclusion Determination Commercial Renewable Energy Systems - Gaston County Solid Waste Biogas Project CX(s) Applied: B1.15, A9, A11, B5.1

89

Page not found | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

81 - 28590 of 28,904 results. 81 - 28590 of 28,904 results. Download CX-001635: Categorical Exclusion Determination Solar American Institute Incubator - Semprius - Massively Parallel Microcell-Based Module Array CX(s) Applied: B3.6 Date: 04/08/2010 Location(s): Durham, North Carolina Office(s): Energy Efficiency and Renewable Energy, Golden Field Office http://energy.gov/nepa/downloads/cx-001635-categorical-exclusion-determination Download CX-001560: Categorical Exclusion Determination Hydroelectric turbine at Water Treatment Plant American Recovery and Reinvestment Act Energy Efficiency and Conservation Block Grant Strategy Only CX(s) Applied: B5.1 Date: 03/31/2010 Location(s): Greensboro, North Carolina Office(s): Energy Efficiency and Renewable Energy, Golden Field Office http://energy.gov/nepa/downloads/cx-001560-categorical-exclusion-determination

90

CX-001635: Categorical Exclusion Determination | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

635: Categorical Exclusion Determination 635: Categorical Exclusion Determination CX-001635: Categorical Exclusion Determination Solar American Institute Incubator - Semprius - Massively Parallel Microcell-Based Module Array CX(s) Applied: B3.6 Date: 04/08/2010 Location(s): Durham, North Carolina Office(s): Energy Efficiency and Renewable Energy, Golden Field Office DOE funding would be used by National Renewable Energy Laboratory (NREL) to support the Solar American Initiative (SAl) Photovoltaic (PV) Technology Incubator. The program is structured to allow innovative approaches targeted at research and development of PV cells and module prototypes. The primary objective of this SAl PV Technology Incubator project is to shorten the timeline for companies to transition prototype and pre-commercial PV

91

Elegant Parallelization Progress Report  

NLE Websites -- All DOE Office Websites (Extended Search)

Elegant Parallelization Progress Report Elegant Parallelization Progress Report 10/24/07 Yusong Wang Michael Borland Hairong Shang Robert Soliday Elegant Parallelization Progress Report Y. Wang, 10/24/07 Simulations with a Large Number of Particles  Recent development  Each slave is allocated memory only for the portion of particles it owns, instead of the memory required for all the particles  On a cluster of quad-cores, configured master to be run on a single node without sharing memory with other slave nodes to allow maximal number of particles to be simulated ( master holds all the particles information for reading and writing)  Current capability and limitations  Simulated with 60 million particles on apex cluster  Can't simulate with 100 million or more particles because of the

92

Parallel processing architecture  

DOE Patents (OSTI)

The parallel processing architecture provides a processor array which accepts input data at a faster rate that its processing elements are able to execute. The main features of this architecture are its programmability, scalability, high bandwidth communication and low cost. It provides high connectivity while maintaining minimum distance between processor elements. This architecture enables construction of a parallel processing with high bandwidth communication in six directions among the neighboring processors. It provides for future growth into more complex and optimized algorithms, and facilitiates incorporation of hardware advances with little effect on currently installed systems. Parallel processing architecture is useful for data sharing in an array, pattern recognition within a data array and sustaining a data input rate which is higher than the pattern recognition algorithm execution time (particle identification in high energy physics).

Crosetto, D.B.

1992-01-01T23:59:59.000Z

93

The STAPL parallel container framework  

Science Conference Proceedings (OSTI)

The Standard Template Adaptive Parallel Library (STAPL) is a parallel programming infrastructure that extends C++ with support for parallelism. It includes a collection of distributed data structures called pContainers that are thread-safe, concurrent ... Keywords: containers, data, languages, libraries, parallel, structures

Gabriel Tanase; Antal Buss; Adam Fidel; Harshvardhan Harshvardhan; Ioannis Papadopoulos; Olga Pearce; Timmie Smith; Nathan Thomas; Xiabing Xu; Nedal Mourad; Jeremy Vu; Mauro Bianco; Nancy M. Amato; Lawrence Rauchwerger

2011-02-01T23:59:59.000Z

94

Massive Variability Surveys from Venezuela  

E-Print Network (OSTI)

At the Venezuela National Astronomical Observatory we are carrying out variability surveys spanning many hundreds of square degrees near the celestial equator, using an 8k x 8k CCD Mosaic Camera optimized for drift-scanning on a 1m Schmidt telescope. Among the initial efforts was a project to obtain the first moderately deep, homogeneous sample of young stars over an area of ? 180sqr.deg. encompassing the entire Orion OB1 association, one of the nearest and most active regions of star formation. The results show that variability is a powerful technique to identify pre-main sequence populations, specially in sparse areas devoid of gas and dust. We are currently developing a massive database, equipped with web-based data mining tools, that will make our data and results available to the astronomical community. 1.

C. D. Impey; C. E. Petry; César Briceño

2003-01-01T23:59:59.000Z

95

Massive Variability Surveys from Venezuela  

E-Print Network (OSTI)

At the Venezuela National Astronomical Observatory we are carrying out variability surveys spanning many hundreds of square degrees near the celestial equator, using an 8k x 8k CCD Mosaic Camera optimized for drift-scanning on a 1m Schmidt telescope. Among the initial efforts was a project to obtain the first moderately deep, homogeneous sample of young stars over an area of ~180sqr.deg. encompassing the entire Orion OB1 association, one of the nearest and most active regions of star formation. The results show that variability is a powerful technique to identify pre-main sequence populations, specially in sparse areas devoid of gas and dust. We are currently developing a massive database, equipped with web-based data mining tools, that will make our data and results available to the astronomical community.

Briceño, C

2003-01-01T23:59:59.000Z

96

Massive Variability Surveys from Venezuela  

E-Print Network (OSTI)

At the Venezuela National Astronomical Observatory we are carrying out variability surveys spanning many hundreds of square degrees near the celestial equator, using an 8k x 8k CCD Mosaic Camera optimized for drift-scanning on a 1m Schmidt telescope. Among the initial efforts was a project to obtain the first moderately deep, homogeneous sample of young stars over an area of ~180sqr.deg. encompassing the entire Orion OB1 association, one of the nearest and most active regions of star formation. The results show that variability is a powerful technique to identify pre-main sequence populations, specially in sparse areas devoid of gas and dust. We are currently developing a massive database, equipped with web-based data mining tools, that will make our data and results available to the astronomical community.

Cesar Briceno

2003-04-03T23:59:59.000Z

97

Exact Solutions in Massive Gravity  

E-Print Network (OSTI)

Massive gravity is a good theoretical laboratory to study modifications of General Relativity. The theory offers a concrete set-up to study models of dark energy, since it admits cosmological self-accelerating solutions in the vacuum, in which the size of the acceleration depends on the graviton mass. Moreover, non-linear gravitational self-interactions, in the proximity of a matter source, manage to mimic the predictions of linearised General Relativity, hence agreeing with solar-system precision measurements. In this article, we review our work in the subject, classifying, on one hand, static solutions, and on the other hand, self-accelerating backgrounds. For what respects static solutions we exhibit black hole configurations, together with other solutions that recover General Relativity near a source via the Vainshtein mechanism. For the self-accelerating solutions we describe a wide class of cosmological backgrounds, including an analysis of their stability.

Gianmassimo Tasinato; Kazuya Koyama; Gustavo Niz

2013-04-02T23:59:59.000Z

98

Complexity and parallel processing  

SciTech Connect

This article is an interview with Richard Karp which discusses the relation of his work to leading-edge computing topics like parallel processing and artificial intelligence. Tracing his experience as a pioneer in highly theoretical computer science, Karp describes how the decision to go against established wisdom led to the work for which he is best known and how a colleague's findings led him to see links between two previously unrelated areas.

Frenkel, K.A.

1986-01-01T23:59:59.000Z

99

Xyce parallel electronic simulator.  

Science Conference Proceedings (OSTI)

This document is a reference guide to the Xyce Parallel Electronic Simulator, and is a companion document to the Xyce Users' Guide. The focus of this document is (to the extent possible) exhaustively list device parameters, solver options, parser options, and other usage details of Xyce. This document is not intended to be a tutorial. Users who are new to circuit simulation are better served by the Xyce Users' Guide.

Keiter, Eric Richard; Mei, Ting; Russo, Thomas V.; Rankin, Eric Lamont; Schiek, Richard Louis; Thornquist, Heidi K.; Fixel, Deborah A.; Coffey, Todd Stirling; Pawlowski, Roger Patrick; Santarelli, Keith R.

2010-05-01T23:59:59.000Z

100

Allinea DDT as a Parallel Debugging Alternative to Totalview  

Science Conference Proceedings (OSTI)

Totalview, from the Etnus Corporation, is a sophisticated and feature rich software debugger for parallel applications. As Totalview has gained in popularity and market share its pricing model has increased to the point where it is often prohibitively expensive for massively parallel supercomputers. Additionally, many of Totalview's advanced features are not used by members of the scientific computing community. For these reasons, supercomputing centers have begun to search for a basic parallel debugging tool which can be used as an alternative to Totalview. As the cost and complexity of Totalview has increased over the years, scientific computing centers have started searching for a viable parallel debugging alternative. DDT (Distributed Debugging Tool) from Allinea Software is a relatively new parallel debugging tool which aims to provide much of the same functionality as Totalview. This review outlines the basic features and limitations of DDT to determine if it can be a reasonable substitute for Totalview. DDT was tested on the NERSC platforms Bassi, Seaborg, Jacquard and Davinci with Fortran90, C, and C++ codes using MPI and OpenMP for parallelism.

Antypas, K.B.

2007-03-05T23:59:59.000Z

Note: This page contains sample records for the topic "massively parallel microcell-based" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

On the Input Problem for Massive Modularity  

Science Conference Proceedings (OSTI)

Jerry Fodor argues that the massive modularity thesis -- the claim that (human) cognition is wholly served by domain specific, autonomous computational devices, i.e., modules -- is a priori ... Keywords: Fodor, Sperber, input problem, language faculty, massive modularity, theory of mind

J. Collins

2005-02-01T23:59:59.000Z

102

Modeling performance of a parallel streaming engine: bridging theory and costs  

Science Conference Proceedings (OSTI)

While data are growing at a speed never seen before, parallel computing is becoming more and more essential to process this massive volume of data in a timely manner. Therefore, recently, concurrent computations have been receiving increasing attention ... Keywords: distributed stream processing engine, measurement, performance model

Ivan Bedini; Sherif Sakr; Bart Theeten; Alessandra Sala; Peter Cogan

2013-04-01T23:59:59.000Z

103

Parallel symbolic computation in ACE  

Science Conference Proceedings (OSTI)

We present an overview of the ACE system, a sound and complete parallel implementation of Prolog that exploits parallelism transparently (i.e., without any user intervention) from AI programs and symbolic applications coded in Prolog. ACE ...

Enrico Pontelli; Gopal Gupta

1997-02-01T23:59:59.000Z

104

Scalable Parallel Programming with CUDA  

Science Conference Proceedings (OSTI)

The advent of multicore CPUs and manycore GPUs means that mainstream processor chips are now parallel systems. Furthermore, their parallelism continues to scale with Moore's law. The challenge is to develop mainstream application software that transparently ...

John Nickolls; Ian Buck; Michael Garland; Kevin Skadron

2008-03-01T23:59:59.000Z

105

Logarithmic time parallel Bayesian inference  

Science Conference Proceedings (OSTI)

I present a parallel algorithm for exact probabilistic inference in Bayesian networks. For polytree networks with n variables, the worstcase time complexity is O(logn) on a CREW PRAM (concurrent-read, exclusive-write parallel random-access ...

David M. Pennock

1998-07-01T23:59:59.000Z

106

Dynamic Graphics Using Quasi Parallelism  

E-Print Network (OSTI)

Dynamic computer graphics is best represented as several processes operating in parallel. Full parallel processing, however, entails much complex mechanism making it difficult to write simple, intuitive programs for ...

Kahn, Kenneth M.

1978-06-01T23:59:59.000Z

107

Implicitly threaded parallelism in manticore  

Science Conference Proceedings (OSTI)

The increasing availability of commodity multicore processors is making parallel computing ever more widespread. In order to exploit its potential, programmers need languages that make the benefits of parallelism accessible and understandable. Previous ...

Matthew Fluet; Mike Rainey; John Reppy; Adam Shaw

2010-11-01T23:59:59.000Z

108

Parallel sphere rendering  

SciTech Connect

Sphere rendering is an important method for visualizing molecular dynamics data. This paper presents a parallel divide-and-conquer algorithm that is almost 90 times faster than current graphics workstations. To render extremely large data sets and large images, the algorithm uses the MIMD features of the supercomputers to divide up the data, render independent partial images, and then finally composite the multiple partial images using an optimal method. The algorithm and performance results are presented for the CM-5 and the T3D.

Krogh, M.; Hansen, C.; Painter, J. [Los Alamos National Lab., NM (United States); de Verdiere, G.C. [CEA Centre d`Etudes de Limeil, 94 - Villeneuve-Saint-Georges (France)

1995-05-01T23:59:59.000Z

109

Applied Parallel Metadata Indexing  

SciTech Connect

The GPFS Archive is parallel archive is a parallel archive used by hundreds of users in the Turquoise collaboration network. It houses 4+ petabytes of data in more than 170 million files. Currently, users must navigate the file system to retrieve their data, requiring them to remember file paths and names. A better solution might allow users to tag data with meaningful labels and searach the archive using standard and user-defined metadata, while maintaining security. last summer, I developed the backend to a tool that adheres to these design goals. The backend works by importing GPFS metadata into a MongoDB cluster, which is then indexed on each attribute. This summer, the author implemented security and developed the user interfae for the search tool. To meet security requirements, each database table is associated with a single user, which only stores records that the user may read, and requires a set of credentials to access. The interface to the search tool is implemented using FUSE (Filesystem in USErspace). FUSE is an intermediate layer that intercepts file system calls and allows the developer to redefine how those calls behave. In the case of this tool, FUSE interfaces with MongoDB to issue queries and populate output. A FUSE implementation is desirable because it allows users to interact with the search tool using commands they are already familiar with. These security and interface additions are essential for a usable product.

Jacobi, Michael R [Los Alamos National Laboratory

2012-08-01T23:59:59.000Z

110

Discovering event evidence amid massive, dynamic datasets  

Science Conference Proceedings (OSTI)

Automated event extraction remains a very difficult challenge requiring information analysts to manually identify key events of interest within massive, dynamic data. Many techniques for extracting events rely on domain specific natural language processing ... Keywords: event detection, events, evolutionary algorithms

Robert M. Patton; Thomas E. Potok

2007-07-01T23:59:59.000Z

111

Improved visibility computation on massive grid terrains  

Science Conference Proceedings (OSTI)

This paper describes the design and engineering of algorithms for computing visibility maps on massive grid terrains. Given a terrain T, specified by the elevations of points in a regular grid, and given a viewpoint v, the visibility ...

Jeremy Fishman; Herman Haverkort; Laura Toma

2009-11-01T23:59:59.000Z

112

Massive Graviton on a Spatial Condensation Web  

E-Print Network (OSTI)

Starting from general relativity and 3 canonical free scalar fields, the background solution spontaneously breaks the Lorentz symmetry, gives rise to a spatial condensation scenario. Such model can be considered as a simplest massive gravity theory. The effective field theory approach in our scenario is valid up to the quantum gravity scale, say, Plank scale. We then apply our massive gravity theory to inflation, the graviton mass removes the IR divergence of the inflationary loop diagram.

Chunshan Lin

2013-07-09T23:59:59.000Z

113

Adventures in parallelism: Celebrating 30 years of parallel computing...  

NLE Websites -- All DOE Office Websites (Extended Search)

established the lab's first experimental parallel computing facility. Today, high-performance computing has become essential to virtually all science and engineering, and Argonne...

114

Massively-parallel electrical-conductivity imaging of hydrocarbons using the Blue Gene/L supercomputer  

E-Print Network (OSTI)

Wahrmund & D. E. Willen ExxonMobil Upstream Research Companyand Dr. Charlie Jing of ExxonMobil who contributed manyLeslie A. Wahrmund ExxonMobil Upstream Research Company,

2008-01-01T23:59:59.000Z

115

Massively parallel computing simulation of fluid flow in the unsaturated zone of Yucca Mountain, Nevada  

E-Print Network (OSTI)

Central Block Area, Yucca Mountain, Nye County, Nevada. Mapunsaturated zone, Yucca Mountain, Nevada. Water-Resourcesisotope distributions at Yucca Mountain. Sandia National

Zhang, Keni; Wu, Yu-Shu; Bodvarsson, G.S.

2001-01-01T23:59:59.000Z

116

Integer-Encoded Massively Parallel Processing of Fast-Learning Fuzzy ARTMAP Neural Networks  

E-Print Network (OSTI)

A. Bahra , Ronald F. DeMarab , Michael N. Georgiopoulosb a HQ STRICOM, AMSTI-ET, 2350 Research categories are self-organized in neural networks1 . Since this time, a number of specific neural network-fold which resulted in a combined training and testing time of under 4 minutes. The organization

DeMara, Ronald F.

117

Parallel Color Coding and Graph Partitioning Enabling Subgraph Counting for Massive Graphs  

E-Print Network (OSTI)

Zhao, Maleq Khan, V.S. Anil Kumar, Madhav V. Marathe Virginia Tech The Problem The problem is to count the error.) a) Color each vertex of G uniformly at random with a color from {1,...,k}. b) Count Xi The total running time of ParSE can be bounded by: Here P is the number of partitions, Q is the number

Khan, Maleq

118

User's Guide for TOUGH2-MP - A Massively Parallel Version of the TOUGH2 Code  

E-Print Network (OSTI)

Wettability on Multiphase Flow Through Porous Media, AIMEMultiphase Flow and Multicomponent Transport in Porous andmultiphase fluids in one, two, and three-dimensional porous

Pruess, Keni Zhang, Yushu Wu, Kasten; Earth Sciences Division

2008-01-01T23:59:59.000Z

119

Massively parallel computing simulation of fluid flow in the unsaturated zone of Yucca Mountain, Nevada  

E-Print Network (OSTI)

flows of multiphase, multicomponents in porous and fracturedmultiphase flow and multicomponent transport in porous and

Zhang, Keni; Wu, Yu-Shu; Bodvarsson, G.S.

2001-01-01T23:59:59.000Z

120

Massively-Parallel Spectral Element Large Eddy Simulation of a Ring-Type Gas Turbine Combustor  

E-Print Network (OSTI)

The average and fluctuating components in a model ring-type gas turbine combustor are characterized using a Large Eddy Simulation at a Reynolds number of 11,000, based on the bulk velocity and the mean channel height. A spatial filter is applied to the incompressible Navier-Stokes equations, and a high pass filtered Smagorinsky model is used to model the sub-grid scales. Two cases are studied: one with only the swirler inlet active, and one with a single row of dilution jets activated, operating at a momentum flux ratio J of 100. The goal of both of these studies is to validate the capabilities of the solver NEK5000 to resolve important flow features inherent to gas turbine combustors by comparing qualitatively to the work of Jakirlic. Both cases show strong evidence of the Precessing Vortex Core, an essential flow feature in gas turbine combustors. Each case captures other important flow characteristics, such as corner eddies, and in general predicts bulk flow movements well. However, the simulations performed quite poorly in terms of predicting turbulence shear stress quantities. Difficulties in properly emulating the turbulent velocity entering the combustor for the swirl, as well as mesh quality concerns, may have skewed the results. Overall, though small length scale quantities were not accurately captured, the large scale quantities were, and this stress test on the HPF LES model will be built upon in future work that looks at more complex combustors.

Camp, Joshua Lane

2011-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "massively parallel microcell-based" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Massively-parallel electrical-conductivity imaging of hydrocarbons using the Blue Gene/L supercomputer  

E-Print Network (OSTI)

at Austin. She has worked at Exxon Production Research (nowDr. Willen joined Exxon Production Research Company in 1980,Research Inc. , SGI, and Exxon Upstream Technical Company in

2008-01-01T23:59:59.000Z

122

Massively-parallel electrical-conductivity imaging of hydrocarbons using the Blue Gene/L supercomputer  

E-Print Network (OSTI)

hydrocarbon, i.e. oil and gas, exploration, and are provenoil and gas reservoirs at the highest resolution possible, and on time scales acceptable to the explorationexploration in basin hydrocarbon systems including the subsurface visualization of earth resistivity volumes applied to oil and gas

2008-01-01T23:59:59.000Z

123

Beyond homogeneous decomposition: scaling long-range forces on Massively Parallel Systems  

Science Conference Proceedings (OSTI)

With supercomputers anticipated to expand from thousands to millions of cores, one of the challenges facing scientists is how to effectively utilize this ever-increasing number. We report here an approach that creates a heterogeneous decomposition by ...

D. F. Richards; J. N. Glosli; B. Chan; M. R. Dorr; E. W. Draeger; J.-L. Fattebert; W. D. Krauss; T. Spelce; F. H. Streitz; M. P. Surh; J. A. Gunnels

2009-11-01T23:59:59.000Z

124

User's Guide for TOUGH2-MP - A Massively Parallel Version of the TOUGH2 Code  

E-Print Network (OSTI)

Modeling Fluid and Heat Flow in Fractured Porous Media, Soc.fluid flows, heat transfer and contaminant transport in porous and fractured media.flows of multicomponent, multiphase fluids in one, two, and three-dimensional porous and fractured media.

Pruess, Keni Zhang, Yushu Wu, Kasten; Earth Sciences Division

2008-01-01T23:59:59.000Z

125

Massively parallel computing simulation of fluid flow in the unsaturated zone of Yucca Mountain, Nevada  

E-Print Network (OSTI)

at Yucca Mountain. Sandia National Laboratories Milestone3672. Sandia National Laboratories, Albuquerque, New Mexico.Computing Research Laboratory, Sandia National Laboratories,

Zhang, Keni; Wu, Yu-Shu; Bodvarsson, G.S.

2001-01-01T23:59:59.000Z

126

Massively parallel electrical conductivity imaging of the subsurface: Applications to hydrocarbon exploration  

E-Print Network (OSTI)

of potential offshore oil and gas reservoirs. The imagingfluids, such as brines, oil, and gas. This limitation haswhere many of the world’s oil and gas deposits remain to be

Newman, G.A.

2009-01-01T23:59:59.000Z

127

Massively-parallel electrical-conductivity imaging of hydrocarbons using the Blue Gene/L supercomputer  

E-Print Network (OSTI)

of potential offshore oil and gas reservoirs. To cope within hydrocarbon, i.e. oil and gas, exploration, and aresuch as brines, water, oil and gas. This has encouraged the

2008-01-01T23:59:59.000Z

128

Scalable implicit finite element solver for massively parallel processing with demonstration to 160K cores  

Science Conference Proceedings (OSTI)

Implicit methods for partial differential equations using unstructured meshes allow for an efficient solution strategy for many real-world problems (e.g., simulation-based virtual surgical planning). Scalable solvers employing these methods not only ...

Onkar Sahni; Min Zhou; Mark S. Shephard; Kenneth E. Jansen

2009-11-01T23:59:59.000Z

129

Nyx: A Massively Parallel AMR Code for Computational Ann S. Almgren1  

E-Print Network (OSTI)

Computing Facility, "Titan Web Page," 2011, http://www.olcf.ornl.gov/titan/. [15] J. Vetter, R. Glassbrook

Bell, John B.

130

Massively parallel simulation of flow and transport in variably saturated porous and fractured media  

E-Print Network (OSTI)

the study of tracer/radionuclide transport through fracture-handling tracer or radionuclide transport on to a parallelfor modeling 3-D tracer/radionuclide transport within the

Wu, Yu-Shu; Zhang, Keni; Pruess, Karsten

2002-01-01T23:59:59.000Z

131

Scaling physics and material science applications on a massively parallel Blue Gene/L system  

Science Conference Proceedings (OSTI)

Blue Gene/L represents a new way to build supercomputers, using a large number of low power processors, together with multiple integrated interconnection networks. Whether real applications can scale to tens of thousands of processors (on a machine like ... Keywords: Blue Gene/L, MPI, applications, scalability, supercomputers

George Almasi; Gyan Bhanot; Alan Gara; Manish Gupta; James Sexton; Bob Walkup; Vasily V. Bulatov; Andrew W. Cook; Bronis R. de Supinski; James N. Glosli; Jeffrey A. Greenough; Francois Gygi; Alison Kubota; Steve Louis; Thomas E. Spelce; Frederick H. Streitz; Peter L. Williams; Robert K. Yates; Charles Archer; Jose Moreira; Charles Rendleman

2005-06-01T23:59:59.000Z

132

A Parallel Tree-SPH code for Galaxy Formation  

E-Print Network (OSTI)

We describe a new implementation of a parallel Tree-SPH code with the aim to simulate Galaxy Formation and Evolution. The code has been parallelized using SHMEM, a Cray proprietary library to handle communications between the 256 processors of the Silicon Graphics T3E massively parallel supercomputer hosted by the Cineca Supercomputing Center (Bologna, Italy). The code combines the Smoothed Particle Hydrodynamics (SPH) method to solve hydro-dynamical equations with the popular Barnes and Hut (1986) tree-code to perform gravity calculation with a NlogN scaling, and it is based on the scalar Tree-SPH code developed by Carraro et al(1998)[MNRAS 297, 1021]. Parallelization is achieved distributing particles along processors according to a work-load criterion. Benchmarks, in terms of load-balance and scalability, of the code are analyzed and critically discussed against the adiabatic collapse of an isothermal gas sphere test using 20,000 particles on 8 processors. The code results balanced at more that 95% level. Increasing the number of processors, the load-balance slightly worsens. The deviation from perfect scalability at increasing number of processors is almost negligible up to 32 processors. Finally we present a simulation of the formation of an X-ray galaxy cluster in a flat cold dark matter cosmology, using 200,000 particles and 32 processors, and compare our results with Evrard (1988) P3M-SPH simulations. Additionaly we have incorporated radiative cooling, star formation, feed-back from SNae of type II and Ia, stellar winds and UV flux from massive stars, and an algorithm to follow the chemical enrichment of the inter-stellar medium. Simulations with some of these ingredients are also presented.

Cesario Lia; Giovanni Carraro

1999-12-06T23:59:59.000Z

133

Implicitly-threaded parallelism in Manticore  

Science Conference Proceedings (OSTI)

The increasing availability of commodity multicore processors is making parallel computing available to the masses. Traditional parallel languages are largely intended for large-scale scientific computing and tend not to be well-suited to programming ... Keywords: data parallelism, exceptions, implictly-threaded parallelism, parallel binding, parallel case

Matthew Fluet; Mike Rainey; John Reppy; Adam Shaw

2008-09-01T23:59:59.000Z

134

Black hole discharge in massive electrodynamics and black hole disappearance in massive gravity  

E-Print Network (OSTI)

We define and calculate the "discharge mode" for a Schwarzschild black hole in massive electrodynamics. For small photon mass, the discharge mode describes the decay of the electric field of a charged star collapsing into a black hole. We argue that a similar "discharge of mass" occurs in massive gravity and leads to a strange process of black hole disappearance.

Mirbabayi, Mehrdad

2013-01-01T23:59:59.000Z

135

Pattern-Based Parallel Programming  

Science Conference Proceedings (OSTI)

The advantages of pattern-based programming have been well-documented in the sequential programming literature. However patterns have yet to make their way into mainstream parallel computing, even though several research tools support them. There are ... Keywords: parallel programming environment, design patterns, frameworks, meta-programming

S. Bromling; S. MacDonald; J. Anvik; J. Schaeffer; D. Szafron; K. Tan

2002-08-01T23:59:59.000Z

136

Checkpointing strategies for parallel jobs  

Science Conference Proceedings (OSTI)

This work provides an analysis of checkpointing strategies for minimizing expected job execution times in an environment that is subject to processor failures. In the case of both sequential and parallel jobs, we give the optimal solution for exponentially ... Keywords: checkpointing, fault-tolerance, parallel job, sequential job

Marin Bougeret; Henri Casanova; Mikael Rabie; Yves Robert; Frédéric Vivien

2011-11-01T23:59:59.000Z

137

Nonlinear optimization and parallel computing  

Science Conference Proceedings (OSTI)

The new computational technologies are having a very strong influence on numerical optimization, in several different ways. Many researchers have been stimulated by the need to either conform the existing numerical techniques to the new parallel architectures ... Keywords: global optimization, heuristics, interior point methods, parallel computing, quadratic programming

A. Migdalas; G. Toraldo; V. Kumar

2003-04-01T23:59:59.000Z

138

Parallel programming for multimedia applications  

Science Conference Proceedings (OSTI)

Computing capabilities are continuing to increase with the availability of multi core and many core processors. The wide availability of multi core processors has made parallel programming possible for end user applications running on desktops, workstations, ... Keywords: CUDA, Multimedia programming, OpenMP, Parallel programming, SIMD

Hari Kalva; Aleksandar Colic; Adriana Garcia; Borko Furht

2011-01-01T23:59:59.000Z

139

Utility Analysis of Parallel Simulation  

Science Conference Proceedings (OSTI)

Parallel computers are used to execute discrete-event simulations in contexts where a serial computer is unable to provide answers fast enough, and/or is unable to hold the simulation state in memory. Traditional research in parallel simulation has focused ...

David M. Nicol

2003-06-01T23:59:59.000Z

140

Parallel TreeSPH: A Tool for Galaxy Formation  

E-Print Network (OSTI)

We describe a new implementation of a parallel Tree-SPH code with the aim to simulate Galaxy Formation and Evolution. The code has been parallelized using SHMEM, a Cray proprietary library to handle communications between the 256 processors of the Silicon Graphics T3E massively parallel supercomputer hosted by the Cineca Super-computing Center (Bologna, Italy). The code combines the Smoothed Particle Hydrodynamics (SPH) method to solve hydro-dynamical equations with the popular Barnes and Hut (1986) tree-code to perform gravity calculation with a $N \\times logN$ scaling, and it is based on the scalar Tree-SPH code developed by Carraro et al (1998)[MNRAS 297, 1021]. Parallelization is achieved distributing particles along processors according to a work-load criterium. Benchmarks, in terms of load-balance and scalability, of the code are analised and critically discussed against the adiabatic collapse of an isothermal gas sphere test using $2 \\times 10^{4}$ particles on 8 processors. The code results balanced at more than 95% level. Increasing the number of processors, the load balance sligthly worsens. The deviation from perfect scalability at increasing number of processors is negligible up to 64 processors. Additionally we have incorporated radiative cooling, star formation, feed-back and an algorithm to follow the chemical enrichment of the interstellar medium.

Cesario Lia; Giovanni Carraro

1999-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "massively parallel microcell-based" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Alexandru Iosup Parallel and Distributed Systems Group  

E-Print Network (OSTI)

Online Games: High Performance Computing and High Quality Time 1 Massivizing Social Games: High used to be art, may now be computing Massivizing Social Games: High Performance Computing and High,000,000 active players Massivizing Social Games: High Performance Computing and High Quality Time ­ A. Iosup 3

Iosup, Alexandru

142

HOW TO FIND YOUNG MASSIVE CLUSTER PROGENITORS  

SciTech Connect

We propose that bound, young massive stellar clusters form from dense clouds that have escape speeds greater than the sound speed in photo-ionized gas. In these clumps, radiative feedback in the form of gas ionization is bottled up, enabling star formation to proceed to sufficiently high efficiency so that the resulting star cluster remains bound even after gas removal. We estimate the observable properties of the massive proto-clusters (MPCs) for existing Galactic plane surveys and suggest how they may be sought in recent and upcoming extragalactic observations. These surveys will potentially provide a significant sample of MPC candidates that will allow us to better understand extreme star-formation and massive cluster formation in the Local Universe.

Bressert, E.; Longmore, S.; Testi, L. [European Southern Observatory, Karl Schwarzschild Str. 2, D-85748 Garching bei Muenchen (Germany); Ginsburg, A.; Bally, J.; Battersby, C. [Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309 (United States)

2012-10-20T23:59:59.000Z

143

Massive Type II in Double Field Theory  

E-Print Network (OSTI)

We provide an extension of the recently constructed double field theory formulation of the low-energy limits of type II strings, in which the RR fields can depend simultaneously on the 10-dimensional space-time coordinates and linearly on the dual winding coordinates. For the special case that only the RR one-form of type IIA carries such a dependence, we obtain the massive deformation of type IIA supergravity due to Romans. For T-dual configurations we obtain a `massive' but non-covariant formulation of type IIB, in which the 10-dimensional diffeomorphism symmetry is deformed by the mass parameter.

Olaf Hohm; Seung Ki Kwak

2011-08-24T23:59:59.000Z

144

NON-AQUEOUS DISSOLUTION OF MASSIVE PLUTONIUM  

DOE Patents (OSTI)

A method is presented for obtaining non-aqueous solutions or plutonium from massive forms of the metal. In the present invention massive plutonium is added to a salt melt consisting of 10 to 40 weight per cent of sodium chloride and the balance zinc chloride. The plutonium reacts at about 800 deg C with the zinc chloride to form a salt bath of plutonium trichloride, sodium chloride, and metallic zinc. The zinc is separated from the salt melt by forcing the molten mixture through a Pyrex filter.

Reavis, J.G.; Leary, J.A.; Walsh, K.A.

1959-05-12T23:59:59.000Z

145

Massive Black Holes: formation and evolution  

E-Print Network (OSTI)

Supermassive black holes are nowadays believed to reside in most local galaxies. Observations have revealed us vast information on the population of local and distant black holes, but the detailed physical properties of these dark massive objects are still to be proven. Accretion of gas and black hole mergers play a fundamental role in determining the two parameters defining a black hole: mass and spin. We briefly review here the basic properties of the population of supermassive black holes, focusing on the still mysterious formation of the first massive black holes, and their evolution from early times to now.

Martin J. Rees; Marta Volonteri

2007-01-17T23:59:59.000Z

146

STAPL: standard template adaptive parallel library  

Science Conference Proceedings (OSTI)

The Standard Template Adaptive Parallel Library (stapl) is a high-productivity parallel programming framework that extends C++ and stl with unified support for shared and distributed memory parallelism. stapl provides distributed data structures (pContainers) ... Keywords: high productivity parallel programming, library, parallel data structures

Antal Buss; Harshvardhan; Ioannis Papadopoulos; Olga Pearce; Timmie Smith; Gabriel Tanase; Nathan Thomas; Xiabing Xu; Mauro Bianco; Nancy M. Amato; Lawrence Rauchwerger

2010-05-01T23:59:59.000Z

147

Models and languages for parallel computation  

Science Conference Proceedings (OSTI)

We survey parallel programming models and languages using six criteria to assess their suitability for realistic portable parallel programming. We argue that an ideal model should by easy to program, should have a software development methodology, should ... Keywords: general-purpose parallel computation, logic programming languages, object-oriented languages, parallel programming languages, parallel programming models, software development methods, taxonomy

David B. Skillicorn; Domenico Talia

1998-06-01T23:59:59.000Z

148

Invitation to embarrassingly parallel computing  

Science Conference Proceedings (OSTI)

A surprising number of physical systems problems are well suited to “embarrassingly parallel" computations which do not require complicated algorithms or specialized hardware. As faculty and students at small institutions

Barbara J. Breen; Christine E. Weidert; John F. Lindner; Lisa May Walker; Kasey Kelly; Evan Heidtmann

2008-01-01T23:59:59.000Z

149

Clustering High Dimensional Massive Scientific Datasets  

Science Conference Proceedings (OSTI)

Many scientific applications can benefit from an efficient clustering algorithm of massively large high dimensional datasets. However most of the developed algorithms are impractical to use when the amount of data is very large. Given N objects ... Keywords: clustering, datasets, high dimensional, scientific

Ekow J. Otoo; Arie Shoshani; Seung-Won Hwang

2001-12-01T23:59:59.000Z

150

Charged Black Holes in New Massive Gravity  

E-Print Network (OSTI)

We construct charged black hole solutions to three-dimensional New Massive Gravity (NMG), by adding electromagnetic Maxwell and Chern-Simons actions. We find charged black holes in the form of warped AdS_3 and "log" solutions in specific critical point. The entropy, mass and angular momentum of these black holes are computed.

Ghodsi, Ahmad

2010-01-01T23:59:59.000Z

151

Massively distributed systems: design issues and challenges  

Science Conference Proceedings (OSTI)

The forty year trend in the computing industry is away from centralized, high unit cost, low unit volume products toward distributed, low unit cost, high unit volume products. The next step in this process is the emergence of massively distributed systems. ...

Dan Nessett

1999-03-01T23:59:59.000Z

152

Synopses for Massive Data: Samples, Histograms, Wavelets, Sketches  

Science Conference Proceedings (OSTI)

Methods for Approximate Query Processing (AQP) are essential for dealing with massive data. They are often the only means of providing interactive response times when exploring massive datasets, and are also needed to handle high speed data streams. ...

Graham Cormode; Minos Garofalakis; Peter J. Haas; Chris Jermaine

2012-01-01T23:59:59.000Z

153

New Mariners and a Massive Map: Berkeley Computers Calculate...  

NLE Websites -- All DOE Office Websites (Extended Search)

Mariners and a Massive Map: Berkeley Computers Calculate What's in the Sky New Mariners and a Massive Map: Berkeley Computers Calculate What's in the Sky February 2, 2012 - 12:08pm...

154

Project massive: a study of online gaming communities  

Science Conference Proceedings (OSTI)

Massively Multiplayer Online Games (MMOGs) continue to be a popular and lucrative sector of the gaming market. Project Massive was created to assess MMOG players' social experiences both inside and outside of their gaming environments and the impact ... Keywords: CSCW, MMO, MMOG, MMORPG, group formation, guilds, massively multiplayer, persistent worlds

A. Fleming Seay; William J. Jerome; Kevin Sang Lee; Robert E. Kraut

2004-04-01T23:59:59.000Z

155

Constraint structure of the three dimensional massive gravity  

Science Conference Proceedings (OSTI)

Constraint analysis of the three-dimensional massive gravity, the so-called new massive gravity, is studied in the Palatini formalism. We show that amongst 6 components of the metric, 2 are dynamical, which is compatible with the existence of one vector massive graviton in the linearized theory (Fierz-Pauli theory).

Sadegh, M.; Shirzad, A. [Department of Physics, Isfahan University of Technology , P.O.Box 84156-83111, Isfahan (Iran, Islamic Republic of); School of Physics, Institute for Research in Fundamental Sciences (IPM), P.O.Box 19395-5531, Tehran (Iran, Islamic Republic of)

2011-04-15T23:59:59.000Z

156

Parallel processing for computer vision  

SciTech Connect

It has been estimated that processor speeds on the order of 1 to 100 billion operations per second will be required to solve some of the current problems in computer vision. This paper overviews the use of parallel processing techniques for various vision tasks using a parallel processing computer architecture known as PASM (partitionable SIMD/MIMD machine). PASM is a large-scale multimicroprocessor system being designed for image processing and pattern recognition. It can be dynamically reconfigured to operate as one or more independent SIMD (single instruction stream-multiple data stream) and/or MIMD (multiple instruction stream-multiple data stream) machines. This paper begins with a discussion of the computational capabilities required for computer vision. It is then shown how parallel processing, and in particular PASM, can be used to meet these needs. 36 references.

Delp, E.J.; Mudge, T.N.; Siegel, L.J.; Siegel, H.J.

1982-01-01T23:59:59.000Z

157

Isolated, Massive Supergiants near the Galactic Center  

E-Print Network (OSTI)

We have carried out a pilot project to assess the feasibility of using radio, infrared, and X-ray emission to identify young, massive stars located between 1 and 25 pc from the Galactic center. We first compared catalogs compiled from the Very Large Array, the Chandra X-ray Observatory, and 2MASS. We identified two massive, young stars: the previously-identified star that is associated with the radio HII region H2, and a newly-identified star that we refer to as CXOGC J174516.1-290315. The infrared spectra of both stars exhibit very strong Br-gamma and He I lines, and resemble those of massive supergiants that have evolved off of the main sequence, but not yet reached the Wolf-Rayet phase. We estimate that each star has a bolometric luminosity >10^6 L_sun. The detection of these two sources in X-rays is surprising, because stars at similar evolutionary states are not uniformly bright X-ray sources. Therefore, we suggest that both stars are in binary systems that contain either OB stars whose winds collide with those of the luminous supergiants, or compact objects that are accreting from the winds of the supergiants. We also identify X-ray emission from a nitrogen-type Wolf-Rayet star and place upper limits on the X-ray luminosities of three more evolved, massive stars that previously have been identified between 1 and 25 pc from Sgr A*. Finally, we briefly discuss the implications that future searches for young stars will have for our understanding of the recent history of star formation near the Galactic center. (abridged)

M. P. Muno; G. C. Bower; A. J. Burgasser; F. K. Baganoff; M. R. Morris; W. N. Brandt

2005-09-21T23:59:59.000Z

158

A parallel descent algorithm for convex programming  

Science Conference Proceedings (OSTI)

Keywords: convex programming, decomposition, descent method, parallel algorithm, trust region method

Masao Fukushima; Mounir Haddou; Van Hien Nguyen; Jean-Jacques Strodiot; Takanobu Sugimoto; Eiki Yamakawa

1996-01-01T23:59:59.000Z

159

PARALLEL OPERATION OF WELDING GENERATORS  

SciTech Connect

Eight 900-amp, 36-kw direct current welding generators driven by eight 60-hp induction motors were operated in parallel to supply up to 7200 amp to resistance loads for heat transfer studies. A description and circuit designs of this installation, which provides safety interlocks and permits sectionalized operation for separate leads, are given. (auth)

Butler, B.H.

1960-06-01T23:59:59.000Z

160

Pervasive parallelism for managed runtimes  

Science Conference Proceedings (OSTI)

Modern programming languages like C# or Java are executed in a managed runtime and offer support for concurrency at a high level of abstraction. However, high-level parallel abstractions (e.g., thread pools) can merely be provided as a library since ...

Albert Noll; Thomas R. Gross

2011-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "massively parallel microcell-based" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Phrase Alignment in Parallel Treebanks  

E-Print Network (OSTI)

This paper describes the usage of XML for representing cross-language phrase alignments in parallel treebanks. We have developed a TreeAligner as a tool for interactively inserting and correcting such alignments as an independent level of treebank annotation. 1

Martin Volk; Sofia Gustafson-capková; Joakim Lundborg; Torsten Marek; Yvonne Samuelsson; Frida Tidström

2006-01-01T23:59:59.000Z

162

Tutorial: Parallel Simulation on Supercomputers  

Science Conference Proceedings (OSTI)

This tutorial introduces typical hardware and software characteristics of extant and emerging supercomputing platforms, and presents issues and solutions in executing large-scale parallel discrete event simulation scenarios on such high performance computing systems. Covered topics include synchronization, model organization, example applications, and observed performance from illustrative large-scale runs.

Perumalla, Kalyan S [ORNL

2012-01-01T23:59:59.000Z

163

Cloning Parallel Simulations MARIA HYBINETTE  

E-Print Network (OSTI)

). Our performance results with a commercial air traffic control sim- ulation demonstrate that cloning parallel simulations can or do play a role include air traffic control, gaming strategy and battle is by permission of the ACM, Inc. To copy otherwise, to republish, to post on servers, or to redistribute to lists

Hybinette, Maria

164

Parallel, Distributed Scripting with Python  

Science Conference Proceedings (OSTI)

Parallel computers used to be, for the most part, one-of-a-kind systems which were extremely difficult to program portably. With SMP architectures, the advent of the POSIX thread API and OpenMP gave developers ways to portably exploit on-the-box shared memory parallelism. Since these architectures didn't scale cost-effectively, distributed memory clusters were developed. The associated MPI message passing libraries gave these systems a portable paradigm too. Having programmers effectively use this paradigm is a somewhat different question. Distributed data has to be explicitly transported via the messaging system in order for it to be useful. In high level languages, the MPI library gives access to data distribution routines in C, C++, and FORTRAN. But we need more than that. Many reasonable and common tasks are best done in (or as extensions to) scripting languages. Consider sysadm tools such as password crackers, file purgers, etc ... These are simple to write in a scripting language such as Python (an open source, portable, and freely available interpreter). But these tasks beg to be done in parallel. Consider the a password checker that checks an encrypted password against a 25,000 word dictionary. This can take around 10 seconds in Python (6 seconds in C). It is trivial to parallelize if you can distribute the information and co-ordinate the work.

Miller, P J

2002-05-24T23:59:59.000Z

165

Dark/visible parallel universes and Big Bang nucleosynthesis  

Science Conference Proceedings (OSTI)

We develop a model for visible matter-dark matter interaction based on the exchange of a massive gray boson called herein the Mulato. Our model hinges on the assumption that all known particles in the visible matter have their counterparts in the dark matter. We postulate six families of particles five of which are dark. This leads to the unavoidable postulation of six parallel worlds, the visible one and five invisible worlds. A close study of big bang nucleosynthesis (BBN), baryon asymmetries, cosmic microwave background (CMB) bounds, galaxy dynamics, together with the Standard Model assumptions, help us to set a limit on the mass and width of the new gauge boson. Modification of the statistics underlying the kinetic energy distribution of particles during the BBN is also discussed. The changes in reaction rates during the BBN due to a departure from the Debye-Hueckel electron screening model is also investigated.

Bertulani, C. A.; Frederico, T.; Fuqua, J.; Hussein, M. S.; Oliveira, O.; Paula, W. de [Department of Physics and Astronomy, Texas A and M University-Commerce, Commerce TX 75429 (United States); Departamento de Fisica, Instituto Tecnologico de Aeronautica, DCTA 12.228-900, Sao Jose dos Campos, SP (Brazil); Department of Physics and Astronomy, Texas A and M University-Commerce, Commerce TX 75429 (United States); Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, 05314-970 Sao Paulo, SP (Brazil); Departamento de Fisica, Instituto Tecnologico de Aeronautica, DCTA 12.228-900, Sao Jose dos Campos, SP, Brazil and Departamento de Fisica, Universidade de Coimbra, 3004-516 Coimbra (Portugal); Departamento de Fisica, Instituto Tecnologico de Aeronautica, DCTA 12.228-900, Sao Jose dos Campos, SP (Brazil)

2012-11-20T23:59:59.000Z

166

Alexandru Iosup Parallel and Distributed Systems Group  

E-Print Network (OSTI)

Online Games: High Performance Computing and High Quality Time 1 Massivizing Social Games: High,000,000 active players Massivizing Social Games: High Performance Computing and High Quality Time ­ A. Iosup 3 Games: High Performance Computing and High Quality Time ­ A. Iosup 4 Sources: MMOGChart, own research

Iosup, Alexandru

167

A Parallel Global Optimization Method for Solving Molecular Cluster and Polymer Conformation Problems  

E-Print Network (OSTI)

Identifying the conformations that a molecular cluster or polymer assumes in nature is an important problem with many practical applications in biology and medicine. It is believed that the naturally occurring molecular conformations minimize or nearly minimize the potential energy of the molecular cluster or polymer. The problem of finding the molecular configuration(s) with the lowest potential energy is a challenging global optimization problem with a potentially huge number of local solutions over a very large parameter space. We have developed a method to solve these types of problems, and have experimented with both molecular cluster and polymer applications, with very promising results. We have implemented the method on powerful massively parallel computers because of the enormous computational requirements of solving these types of problems. The parallel algorithms are interesting asynchronous, multi-level parallel algorithms. 1 Introduction The general problem of finding the ...

Richard H. Byrd; Elizabeth Eskow; André van der Hoek; Robert B. Schnabel; Klaas P. B. Oldenkamp

1995-01-01T23:59:59.000Z

168

Development of Advanced Massive Heterogeneous Sensor Networks  

NLE Websites -- All DOE Office Websites (Extended Search)

Advanced Massive Heterogeneous Sensor Networks Research Team * Doug McCorkle * Kris Bryden * Mark Bryden Ames Laboratory U of Maryland * Ashwani Gupta * Miao Yu Power Plant Challenges * Conflicting goals of reliable low cost energy and climate change mitigation * Large investment in current infrastructure * Little implementation of information technologies Sensors ... * will be "free" * will be small (lick 'n stick) * will be smart * will be ubiquitous Low cost improvements in sensing for control and condition monitoring can result in big improvements in cost and carbon emissions * "... develop the understandings, algorithms, and control strategies needed to utilize large-scale, high- density sensor networks in advanced power plants." * Develop techniques for the

169

Transport coefficients of a massive pion gas  

E-Print Network (OSTI)

We review or main results concerning the transport coefficients of a light meson gas, in particular we focus on the case of a massive pion gas. Leading order results according to the chiral power-counting are presented for the DC electrical conductivity, thermal conductivity, shear viscosity, and bulk viscosity. We also comment on the possible correlation between the bulk viscosity and the trace anomaly in QCD, as well as the relation between unitarity and a minimum of the quotient $\\eta/s$ near the phase transition.

D. Fernandez-Fraile; A. Gomez Nicola

2009-12-20T23:59:59.000Z

170

Search for massive rare particles with MACRO  

E-Print Network (OSTI)

Massive rare particles have been searched for in the penetrating cosmic radiation using the MACRO apparatus at the Gran Sasso National Laboratories. Liquid scintillators, streamer tubes and nuclear track detectors have been used to search for magnetic monopoles (MMs). Based on no observation of such signals, stringent flux limits are established for MMs as slow as a few 10^(-5)c. The methods based on the scintillator and on the nuclear track subdetectors were also applied to search for nuclearites. Preliminary results of the searches for charged Q-balls are also presented.

The MACRO Collaboration

2000-09-01T23:59:59.000Z

171

QUARK MATTER IN MASSIVE COMPACT STARS  

SciTech Connect

The recent observation of the pulsar PSR J1614-2230 with a mass of 1.97 {+-} 0.04 M{sub sun} gives a strong constraint on the quark and nuclear matter equations of state (EoS). We explore the parameter ranges for a parameterized EoS for quark stars. We find that strange stars, made of absolutely stable strange quark matter, comply with the new constraint only if effects from the strong coupling constant and color-superconductivity are taken into account. Hybrid stars, compact stars with a quark matter core and a hadronic outer layer, can be as massive as 2 M{sub sun}, but only for a significantly limited range of parameters. We demonstrate that the appearance of quark matter in massive stars crucially depends on the stiffness of the nuclear matter EoS. We show that the masses of hybrid stars stay below the ones of hadronic and pure quark stars, due to the softening of the EoS at the quark-hadron phase transition.

Weissenborn, Simon; Pagliara, Giuseppe; Schaffner-Bielich, Juergen [Institute for Theoretical Physics, Ruprecht-Karls University, 69120 Heidelberg (Germany); Sagert, Irina [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Hempel, Matthias [Department of Physics, University of Basel, 4056 Basel (Switzerland)

2011-10-10T23:59:59.000Z

172

Knowledge Discovery from Massive Healthcare Claims Data  

SciTech Connect

The role of big data in addressing the needs of the present healthcare system in US and rest of the world has been echoed by government, private, and academic sectors. There has been a growing emphasis to explore the promise of big data analytics in tapping the potential of the massive healthcare data emanating from private and government health insurance providers. While the domain implications of such collaboration are well known, this type of data has been explored to a limited extent in the data mining community. The objective of this paper is two fold: first, we introduce the emerging domain of big"healthcare claims data to the KDD community, and second, we describe the success and challenges that we encountered in analyzing this data using state of art analytics for massive data. Specically, we translate the problem of analyzing healthcare data into some of the most well-known analysis problems in the data mining community, social network analysis, text mining, and temporal analysis and higher order feature construction, and describe how advances within each of these areas can be leveraged to understand the domain of healthcare. Each case study illustrates a unique intersection of data mining and healthcare with a common objective of improving the cost-care ratio by mining for opportunities to improve healthcare operations and reducing hat seems to fall under fraud, waste,and abuse.

Chandola, Varun [ORNL; Sukumar, Sreenivas R [ORNL; Schryver, Jack C [ORNL

2013-01-01T23:59:59.000Z

173

Massive Supermultiplets in Four-Dimensional Superstring Theory  

E-Print Network (OSTI)

We extend the discussion of [1] on massive Regge excitations on the first mass level of four-dimensional superstring theory. For the lightest massive modes of the open string sector, universal supermultiplets common to all four-dimensional compactifications with N = 1, 2 and N = 4 spacetime supersymmetry are constructed respectively -- both their vertex operators and their supersymmetry variations. Massive spinor helicity methods shed light on the interplay between individual polarization states.

Feng, Wan-Zhe; Schlotterer, Oliver

2012-01-01T23:59:59.000Z

174

Implementing a Gaussian Process Learning Algorithm in Mixed Parallel Environment  

Science Conference Proceedings (OSTI)

In this paper, we present a scalability analysis of a parallel Gaussian process training algorithm to simultaneously analyze a massive number of time series. We study three different parallel implementations: using threads, MPI, and a hybrid implementation using threads and MPI. We compare the scalability for the multi-threaded implementation on three different hardware platforms: a Mac desktop with two quad-core Intel Xeon processors (16 virtual cores), a Linux cluster node with four quad-core 2.3 GHz AMD Opteron processors, and SGI Altix ICE 8200 cluster node with two quad-core Intel Xeon processors (16 virtual cores). We also study the scalability of the MPI based and the hybrid MPI and thread based implementations on the SGI cluster with 128 nodes (2048 cores). Experimental results show that the hybrid implementation scales better than the multi-threaded and MPI based implementations. The hybrid implementation, using 1536 cores, can analyze a remote sensing data set with over 4 million time series in nearly 5 seconds while the serial algorithm takes nearly 12 hours to process the same data set.

Chandola, Varun [ORNL; Vatsavai, Raju [ORNL

2011-01-01T23:59:59.000Z

175

Automatic Parallelization With Statistical Accuracy Bounds  

E-Print Network (OSTI)

Traditional parallelizing compilers are designed to generate parallel programs that produce identical outputs as the original sequential program. The difficulty of performing the program analysis required to satisfy this ...

Kim, Deokhwan

2010-02-10T23:59:59.000Z

176

A Parallelizing Compiler Based on Partial Evaluation  

E-Print Network (OSTI)

We constructed a parallelizing compiler that utilizes partial evaluation to achieve efficient parallel object code from very high-level data independent source programs. On several important scientific applications, ...

Surati, Rajeev

1993-07-01T23:59:59.000Z

177

Exploiting the Parallelism Exposed by Partial Evaluation  

E-Print Network (OSTI)

We describe the key role played by partial evaluation in the Supercomputing Toolkit, a parallel computing system for scientific applications that effectively exploits the vast amount of parallelism exposed by partial ...

Surati, Rajeev

1994-05-01T23:59:59.000Z

178

A practical oracle for sequential code parallelization  

E-Print Network (OSTI)

pipeline parallelism, expressed in (a) as a DOACROSS loop. In this example, a cross-iteration dependency length

Garcia, Saturnino; Garcia, Saturnino

2012-01-01T23:59:59.000Z

179

Complete Automation and Distribution of Parallel Simulation ...  

Science Conference Proceedings (OSTI)

... materials science, many problems require the execution of numerous parallel simulation tasks on High Performance Computing (HPC) resources. ...

2013-07-18T23:59:59.000Z

180

Optimization Online - A PARALLEL interior point decomposition ...  

E-Print Network (OSTI)

Dec 4, 2006... and decomposed and distributed subproblems (smaller SDPs) in a parallel and distributed high performance computing environment.

Note: This page contains sample records for the topic "massively parallel microcell-based" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Tempest: a substrate for portable parallel programs  

Science Conference Proceedings (OSTI)

The paper describes Tempest, a collection of mechanisms for communication and synchronization in parallel programs. With these mechanisms, authors of compilers, libraries, and application programs can exploit-across a wide range of hardware platforms-the ... Keywords: Tempest, hybrid combinations, message passing, parallel machines, parallel programming, performance results, portable interface, portable parallel programs, shared memory, shared memory systems, software portability, software reusability, software standards, stock hardware

M. D. Hill; J. R. Larus; D. A. Wood

1995-03-01T23:59:59.000Z

182

Adding parallelism to visual data flow programs  

Science Conference Proceedings (OSTI)

Programming in parallel is an error-prone and complex task compounded by the lack of tool support for both programming and debugging. Recent advances in compiler-directed shared memory APIs, such as OpenMP, have made shared-memory parallelism more widely ... Keywords: data flow, parallel, visual language

Philip Cox; Simon Gauvin; Andrew Rau-Chaplin

2005-05-01T23:59:59.000Z

183

Fusion of Loops for Parallelism and Locality  

Science Conference Proceedings (OSTI)

Abstract¿Loop fusion improves data locality and reduces synchronization in data-parallel applications. However, loop fusion is not always legal. Even when legal, fusion may introduce loop-carried dependences which prevent parallelism. In addition, performance ... Keywords: Locality enhancement, loop fusion, cache conflicts, loop transformations, data-parallel applications, scalable shared-memory multiprocessors.

Naraig Manjikian; Tarek S. Abdelrahman

1997-02-01T23:59:59.000Z

184

PLFS: a checkpoint filesystem for parallel applications  

Science Conference Proceedings (OSTI)

Parallel applications running across thousands of processors must protect themselves from inevitable system failures. Many applications insulate themselves from failures by checkpointing. For many applications, checkpointing into a shared single file ... Keywords: check-pointing, high performance computing, parallel computing, parallel file systems and IO

John Bent; Garth Gibson; Gary Grider; Ben McClelland; Paul Nowoczynski; James Nunez; Milo Polte; Meghan Wingate

2009-11-01T23:59:59.000Z

185

Performance Metrics for Embedded Parallel Pipelines  

Science Conference Proceedings (OSTI)

Abstract¿A statistical approach to performance prediction is applied to a system development methodology for pipelines comprised of independent parallel stages. The methodology is aimed at distributed memory machines employing medium-grained parallelization. ... Keywords: Performance prediction, parallel pipelines, real-time systems, order statistics.

Martin Fleury; Andrew C. Downton; Adrian F. Clark

2000-11-01T23:59:59.000Z

186

Threads and or-parallelism unified  

Science Conference Proceedings (OSTI)

One of the main advantages of Logic Programming (LP) is that it provides an excellent framework for the parallel execution of programs. In this work we investigate novel techniques to efficiently exploit parallelism from real-world applications in low ... Keywords: implementation, multi-threading, or-parallelism

Vítor Santos costa; InÊs Dutra; Ricardo Rocha

2010-07-01T23:59:59.000Z

187

Bit-serial RISC processing element for parallel processing  

E-Print Network (OSTI)

Over the past five decades, electronic computers have gone through five generations of development. Each generation is distinguished by the tremendous improvement in performance over its predecessors. The improvements are mostly attributed to the increase in the chip and memory transistor density. Now, chip density and complexity are approaching their physical limits due to limitations imposed by the speed of light. This has prompted interset in scaling system resources by the number of processors used, and enlarging memory capacity. Scalable architectures delivering a sustained performance are desired in both sequential and parallel computers. However, parallel computers having a higher potential to deliver scalable performance are poised to become the new generation of electronic computers. The processing element architecture of this thesis is a unique combination of new computer generation concepts and early computers simplicity. This is a desirable combination of techniques and architecture for a processing element designed to be used in scalable massively parallel systems where it is advantageous to reduce space and power needs without sacrificing independent processor operation. The research that was conducted includes the design and development of a bitserial processing element and its associated on-chip memory. The goal of this design effort was to obtain a stand-alone processor with communication capabilities using a minimum number of instructions and a small instruction and data memory suitable for Fine-grain computing. The processing element has a two-phase clocking scheme where each clock can run at 40 MHZ. The processing chip is setup to be programmed to a Field Programmable Gate Array (FPGA) device using Altera programming software. The minimum requirement for the FPGA device is 56 input/output pins with a maximum 25ns delay and a 65 mm floorplan size.

Haidar, Faisal A

1994-01-01T23:59:59.000Z

188

Massive infrastructures are needed to support supercomputers  

NLE Websites -- All DOE Office Websites (Extended Search)

"Under the floor" of a supercomputer "Under the floor" of a supercomputer National Security Science magazine Latest Issue:April 2013 All Issues » submit Massive infrastructures are needed to support supercomputers Megawatts of power, millions of gallons of water, a football-field-size floor March 25, 2013 Tip of the computing iceberg The supercomputer room at Los Alamos is vast-essentially an acre. And this is just the tip of the iceberg. What's really amazing is what's under that floor. When a supercomputer covers 6,000 square feet of floor space, how do its guardians find and fix problems in only an hour? What's "under the floor" of a supercomputer? SUMMARY The infrastructure required to support a supercomputer includes megawatts of electricity to power it,millions of gallons of water to cool

189

Massive superstring scatterings in the Regge regime  

Science Conference Proceedings (OSTI)

We calculate four classes of high-energy massive string scattering amplitudes of fermionic string theory at arbitrary mass levels in the Regge regime (RR). We show that all four leading order amplitudes in the RR can be expressed in terms of the Kummer function of the second kind. Based on the summation algorithm of a set of extended signed Stirling number identities, we show that all four ratios calculated previously by the method of decoupling of zero-norm states among scattering amplitudes in the Gross regime can be extracted from this Kummer function in the RR. Finally, we conjecture and give evidence that the existence of these four Gross regime ratios in the RR persists to subleading orders in the Regge expansion of all high-energy fermionic string scattering amplitudes.

He Song; Lee, Jen-Chi; Takahashi, Keijiro; Yang Yi [Institute of High Energy Physics, Chinese Academic of Sciences, Beijing (China); Department of Electrophysics, National Chiao-Tung University and Physics Division, National Center for Theoretical Sciences, Hsinchu, Taiwan (China); Department of Electrophysics, National Chiao-Tung University, Hsinchu, Taiwan (China); Department of Electrophysics, National Chiao-Tung University and Physics Division, National Center for Theoretical Sciences, Hsinchu, Taiwan (China)

2011-03-15T23:59:59.000Z

190

Progress in the physics of massive neutrinos  

E-Print Network (OSTI)

The current status of the physics of massive neutrinos is reviewed with a forward-looking emphasis. The article begins with the general phenomenology of neutrino oscillations in vacuum and matter and documents the experimental evidence for oscillations of solar, reactor, atmospheric and accelerator neutrinos. Both active and sterile oscillation possibilities are considered. The impact of cosmology (BBN, CMB, leptogenesis) and astrophysics (supernovae, highest energy cosmic rays) on neutrino observables and vice versa, is evaluated. The predictions of grand unified, radiative and other models of neutrino mass are discussed. Ways of determining the unknown parameters of three-neutrino oscillations are assessed, taking into account eight-fold degeneracies in parameters that yield the same oscillation probabilities, as well as ways to determine the absolute neutrino mass scale (from beta-decay, neutrinoless double-beta decay, large scale structure and Z-bursts). Critical unknowns at present are the amplitude of \

V. Barger; D. Marfatia; K. Whisnant

2003-08-12T23:59:59.000Z

191

Evaluating In-Clique and Topological Parallelism Strategies for Junction Tree-Based Bayesian Inference Algorithm on the Cray XMT  

SciTech Connect

Long viewed as a strong statistical inference technique, Bayesian networks have emerged to be an important class of applications for high-performance computing. We have applied an architecture-conscious approach to parallelizing the Lauritzen-Spiegelhalter Junction Tree algorithm for exact inferencing in Bayesian networks. In optimizing the Junction Tree algorithm, we have implemented both in-clique and topological parallelism strategies to best leverage the fine-grained synchronization and massive-scale multithreading of the Cray XMT architecture. Two topological techniques were developed to parallelize the evidence propagation process through the Bayesian network. One technique involves performing intelligent scheduling of junction tree nodes based on its topology and relative size. The second technique involves decomposing the junction tree into a much finer tree-like representation to offer much more opportunities for parallelism. We evaluate these optimizations on five different Bayesian networks and report our findings and observations. Another important contribution of this paper is to demonstrate the application of massive-scale multithreading for load balancing and use of implicit parallelism-based compiler optimizations in designing scalable inferencing algorithms.

Chin, George; Choudhury, Sutanay; Kangas, Lars J.; McFarlane, Sally A.; Marquez, Andres

2011-09-01T23:59:59.000Z

192

Xyce parallel electronic simulator design.  

Science Conference Proceedings (OSTI)

This document is the Xyce Circuit Simulator developer guide. Xyce has been designed from the 'ground up' to be a SPICE-compatible, distributed memory parallel circuit simulator. While it is in many respects a research code, Xyce is intended to be a production simulator. As such, having software quality engineering (SQE) procedures in place to insure a high level of code quality and robustness are essential. Version control, issue tracking customer support, C++ style guildlines and the Xyce release process are all described. The Xyce Parallel Electronic Simulator has been under development at Sandia since 1999. Historically, Xyce has mostly been funded by ASC, the original focus of Xyce development has primarily been related to circuits for nuclear weapons. However, this has not been the only focus and it is expected that the project will diversify. Like many ASC projects, Xyce is a group development effort, which involves a number of researchers, engineers, scientists, mathmaticians and computer scientists. In addition to diversity of background, it is to be expected on long term projects for there to be a certain amount of staff turnover, as people move on to different projects. As a result, it is very important that the project maintain high software quality standards. The point of this document is to formally document a number of the software quality practices followed by the Xyce team in one place. Also, it is hoped that this document will be a good source of information for new developers.

Thornquist, Heidi K.; Rankin, Eric Lamont; Mei, Ting; Schiek, Richard Louis; Keiter, Eric Richard; Russo, Thomas V.

2010-09-01T23:59:59.000Z

193

LACIO: A New Collective I/O Strategy for Parallel I/O Systems  

Science Conference Proceedings (OSTI)

Parallel applications benefit considerably from the rapid advance of processor architectures and the available massive computational capability, but their performance suffers from large latency of I/O accesses. The poor I/O performance has been attributed as a critical cause of the low sustained performance of parallel systems. Collective I/O is widely considered a critical solution that exploits the correlation among I/O accesses from multiple processes of a parallel application and optimizes the I/O performance. However, the conventional collective I/O strategy makes the optimization decision based on the logical file layout to avoid multiple file system calls and does not take the physical data layout into consideration. On the other hand, the physical data layout in fact decides the actual I/O access locality and concurrency. In this study, we propose a new collective I/O strategy that is aware of the underlying physical data layout. We confirm that the new Layout-Aware Collective I/O (LACIO) improves the performance of current parallel I/O systems effectively with the help of noncontiguous file system calls. It holds promise in improving the I/O performance for parallel systems.

Chen, Yong [ORNL; Sun, Xian-He [Illinois Institute of Technology; Thakur, Dr. Rajeev [Argonne National Laboratory (ANL); Roth, Philip C [ORNL; Gropp, William D [University of Illinois, Urbana-Champaign

2011-01-01T23:59:59.000Z

194

Parallel Objects and Field Equations  

E-Print Network (OSTI)

This paper considers a generalization of the existing concept of parallel (with respect to a given connection) geometric objects and its possible usage as a suggesting rule in searching for adequate field equations in theoretical physics. The generalization tries to represent mathematically the two-sided nature of the physical objects, the {\\it change} and the {\\it conservation}. The physical objects are presented mathematically by sections $\\Psi$ of vector bundles, the admissible changes $D\\Psi$ are described as a rsult of the action of appropriate differential operators $D$ on these sections, and the conservation propertieis are accounted for by the requirement that suitable projections of $D\\Psi$ on $\\Psi$ and on other appropriate sections must be zero. It is shown that the most important equations of theoretical physics obey this rule. Extended forms of Maxwell and Yang-Mills equations are also considered.

Stoil Donev; Maria Tashkova

2002-05-30T23:59:59.000Z

195

Device for balancing parallel strings  

SciTech Connect

A battery plant is described which features magnetic circuit means in association with each of the battery strings in the battery plant for balancing the electrical current flow through the battery strings by equalizing the voltage across each of the battery strings. Each of the magnetic circuit means generally comprises means for sensing the electrical current flow through one of the battery strings, and a saturable reactor having a main winding connected electrically in series with the battery string, a bias winding connected to a source of alternating current and a control winding connected to a variable source of direct current controlled by the sensing means. Each of the battery strings is formed by a plurality of batteries connected electrically in series, and these battery strings are connected electrically in parallel across common bus conductors.

Mashikian, Matthew S. (Storrs, CT)

1985-01-01T23:59:59.000Z

196

Parallel FE Approximation of the Even/Odd Parity Form of the Linear Boltzmann Equation  

Science Conference Proceedings (OSTI)

A novel solution method has been developed to solve the linear Boltzmann equation on an unstructured triangular mesh. Instead of tackling the first-order form of the equation, this approach is based on the even/odd-parity form in conjunction with the conventional mdtigroup discrete-ordinates approximation. The finite element method is used to treat the spatial dependence. The solution method is unique in that the space-direction dependence is solved simultaneously, eliminating the need for the conventional inner iterations, and the method is well suited for massively parallel computers.

Drumm, Clifton R.; Lorenz, Jens

1999-07-21T23:59:59.000Z

197

Active galactic nuclei and massive galaxy cores  

E-Print Network (OSTI)

(Context) Central active galactic nuclei (AGN) are supposed to play a key role in the evolution of their host galaxies. In particular, the dynamical and physical properties of the gas core must be affected by the injected energy. (Aims) Our aim is to study the effects of an AGN on the dark matter profile and on the central stellar light distribution in massive early type galaxies. (Methods) By performing self-consistent N-body simulations, we assume in our analysis that periodic bipolar outbursts from a central AGN can induce harmonic oscillatory motions on both sides of the gas core. (Results) Using realistic AGN properties, we find that the motions of the gas core, driven by such feedback processes, can flatten the dark matter and/or stellar profiles after 4-5 Gyr. These results are consistent with recent observational studies that suggest that most giant elliptical galaxies have cores or are "missing light" in their inner part. Since stars behave as a "collisionless" fluid similar to dark matter, the density profile both of stars and dark matter should be affected in a similar way, leading to an effective reduction in the central brightness.

Sebastien Peirani; Scott Kay; Joe Silk

2006-12-16T23:59:59.000Z

198

Radiation Pressure in Massive Star Formation  

E-Print Network (OSTI)

Stars with masses of >~ 20 solar masses have short Kelvin times that enable them to reach the main sequence while still accreting from their natal clouds. The resulting nuclear burning produces a huge luminosity and a correspondingly large radiation pressure force on dust grains in the accreting gas. This effect may limit the upper mass of stars that can form by accretion. Indeed, simulations and analytic calculations to date have been unable to resolve the mystery of how stars of 50 solar masses and up form. We present two new ideas to solve the radiation pressure problem. First, we use three-dimensional radiation hydrodynamic adaptive mesh refinement simulations to study the collapse of massive cores. We find that in three dimensions a configuration in which radiation holds up an infalling envelope is Rayleigh-Taylor unstable, leading radiation driven bubbles to collapse and accretion to continue. We also present Monte Carlo radiative transfer calculations showing that the cavities created by protostellar winds provides a valve that allow radiation to escape the accreting envelope, further reducing the ability of radiation pressure to inhibit accretion.

Mark R. Krumholz; Richard I. Klein; Christopher F. McKee

2005-10-14T23:59:59.000Z

199

Bin-Hash Indexing: A Parallel Method for Fast Query Processing  

SciTech Connect

This paper presents a new parallel indexing data structure for answering queries. The index, called Bin-Hash, offers extremely high levels of concurrency, and is therefore well-suited for the emerging commodity of parallel processors, such as multi-cores, cell processors, and general purpose graphics processing units (GPU). The Bin-Hash approach first bins the base data, and then partitions and separately stores the values in each bin as a perfect spatial hash table. To answer a query, we first determine whether or not a record satisfies the query conditions based on the bin boundaries. For the bins with records that can not be resolved, we examine the spatial hash tables. The procedures for examining the bin numbers and the spatial hash tables offer the maximum possible level of concurrency; all records are able to be evaluated by our procedure independently in parallel. Additionally, our Bin-Hash procedures access much smaller amounts of data than similar parallel methods, such as the projection index. This smaller data footprint is critical for certain parallel processors, like GPUs, where memory resources are limited. To demonstrate the effectiveness of Bin-Hash, we implement it on a GPU using the data-parallel programming language CUDA. The concurrency offered by the Bin-Hash index allows us to fully utilize the GPU's massive parallelism in our work; over 12,000 records can be simultaneously evaluated at any one time. We show that our new query processing method is an order of magnitude faster than current state-of-the-art CPU-based indexing technologies. Additionally, we compare our performance to existing GPU-based projection index strategies.

Bethel, Edward W; Gosink, Luke J.; Wu, Kesheng; Bethel, Edward Wes; Owens, John D.; Joy, Kenneth I.

2008-06-27T23:59:59.000Z

200

Time-parallel multiscale/multiphysics framework  

Science Conference Proceedings (OSTI)

We introduce the time-parallel compound wavelet matrix method (tpCWM) for modeling the temporal evolution of multiscale and multiphysics systems. The method couples time parallel (TP) and CWM methods operating at different spatial and temporal scales. ... Keywords: 02.00.00, 02.10.Jf, 05.10.-a, 46.15.-x, 47.70.Fw, Parallel-in-time, Wavelet-based multiscaling

G. Frantziskonis; K. Muralidharan; P. Deymier; S. Simunovic; P. Nukala; S. Pannala

2009-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "massively parallel microcell-based" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Massive gravity with mass term in three dimensions  

Science Conference Proceedings (OSTI)

We analyze the effect of the Pauli-Fierz mass term on a recently established, new massive gravity theory in three space-time dimensions. We show that the Pauli-Fierz mass term makes the new massive gravity theory nonunitary. Moreover, although we add the gravitational Chern-Simons term to this model, the situation remains unchanged and the theory stays nonunitary despite that the structure of the graviton propagator is greatly changed. Thus, the Pauli-Fierz mass term is not allowed to coexist with mass-generating higher-derivative terms in the new massive gravity.

Nakasone, Masashi; Oda, Ichiro [Department of Physics, Faculty of Science, University of the Ryukyus, Nishihara, Okinawa 903-0213 (Japan)

2009-05-15T23:59:59.000Z

202

Cost hierarchies for abstract parallel machines  

E-Print Network (OSTI)

O'Donnell,J.T. Rauber,T. Ruenger,G. 13th International Workshop on Languages and Compilers for Parallel Computing (LCPC 2000) LNCS, Springer

O'Donnell, J.T.

203

The SpiceC Parallel Programming System  

E-Print Network (OSTI)

xv List of Tables Compiler directives implemented byby the parallelized loops, and number of directives used forparallelized with the SpiceC directives. There are 9 loops

Feng, Min

2012-01-01T23:59:59.000Z

204

A modular neural interface for massively parallel recording and control : subsystem design considerations for research and clinical applications  

E-Print Network (OSTI)

The closed-loop Brain-Machine Interface (BMI) has long been a dream for clinicians and neuroscience researchers alike - that is, the ability to extract meaningful information from the brain, perform computation on this ...

Wentz, Christian T

2010-01-01T23:59:59.000Z

205

MASSIVELY PARALLEL FULLY COUPLED IMPLICIT MODELING OF COUPLED THERMAL-HYDROLOGICAL-MECHANICAL PROCESSES FOR ENHANCED GEOTHERMAL SYSTEM RESERVOIRS  

SciTech Connect

Development of enhanced geothermal systems (EGS) will require creation of a reservoir of sufficient volume to enable commercial-scale heat transfer from the reservoir rocks to the working fluid. A key assumption associated with reservoir creation/stimulation is that sufficient rock volumes can be hydraulically fractured via both tensile and shear failure, and more importantly by reactivation of naturally existing fractures (by shearing) to create the reservoir. The advancement of EGS greatly depends on our understanding of the dynamics of the intimately coupled rock-fracture-fluid system and our ability to reliably predict how reservoirs behave under stimulation and production. In order to increase our understanding of how reservoirs behave under these conditions, we have developed a physics-based rock deformation and fracture propagation simulator by coupling a discrete element model (DEM) for fracturing with a continuum multiphase flow and heat transport model. In DEM simulations, solid rock is represented by a network of discrete elements (often referred as particles) connected by various types of mechanical bonds such as springs, elastic beams or bonds that have more complex properties (such as stress-dependent elastic constants). Fracturing is represented explicitly as broken bonds (microcracks), which form and coalesce into macroscopic fractures when external load is applied. DEM models have been applied to a very wide range of fracturing processes from the molecular scale (where thermal fluctuations play an important role) to scales on the order of 1 km or greater. In this approach, the continuum flow and heat transport equations are solved on an underlying fixed finite element grid with evolving porosity and permeability for each grid cell that depends on the local structure of the discrete element network (such as DEM particle density). The fluid pressure gradient exerts forces on individual elements of the DEM network, which therefore deforms and fractures. Such deformation/fracturing in turn changes the permeability, which again changes the evolution of fluid pressure, coupling the two phenomena. The intimate coupling between fracturing and fluid flow makes the meso-scale DEM simulations necessary, as these methods have substantial advantages over conventional continuum mechanical models of elastic rock deformation. The challenges that must be overcome to simulate EGS reservoir stimulation, preliminary results, progress to date and near future research directions and opportunities will be discussed.

Robert Podgorney; Hai Huang; Derek Gaston

2010-02-01T23:59:59.000Z

206

Massively-Parallel Dislocation Dynamics Simulations Wei Cai, Vasily V. Bulatov, Tim G. Pierce, Masato Hiratani, Moono  

E-Print Network (OSTI)

PSL Climate Survey in October 2006. (PSL) Memo sent requesting limit email usage and encourage face- nities" shed some light on existing issues. Some of those issues have already been addressed. Practical

Cai, Wei

207

Massive Cement Pour into Hanford Site Nuclear Facility Underway: Recovery  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Massive Cement Pour into Hanford Site Nuclear Facility Underway: Massive Cement Pour into Hanford Site Nuclear Facility Underway: Recovery Act Funding Puts U Canyon in Home Stretch of Demolition Preparations Massive Cement Pour into Hanford Site Nuclear Facility Underway: Recovery Act Funding Puts U Canyon in Home Stretch of Demolition Preparations June 14, 2011 - 12:00pm Addthis Media Contacts Andre Armstrong, CH2M HILL Plateau Remediation Company (509) 376-6773 Andre_L_Armstrong@rl.gov Geoff Tyree, DOE (509) 376-4171 Geoffrey.Tyree@rl.doe.gov RICHLAND, Wash. - Hanford workers are pouring enough cement-like material to fill six Olympic-size wimming pools in one of the U.S. Department of Energy's (DOE) largest nuclear facilities at the Hanford Site in southeast Washington State to prepare the massive building for demolition.

208

Protecting Recovery Act Cleanup Site During Massive Wildfire | Department  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Protecting Recovery Act Cleanup Site During Massive Wildfire Protecting Recovery Act Cleanup Site During Massive Wildfire Protecting Recovery Act Cleanup Site During Massive Wildfire Effective safety procedures in place at Los Alamos National Laboratory would have provided protections in the event that the raging Las Conchas fire had spread to the site of an American Recovery and Reinvestment Act project. "Our procedures not only placed the waste excavation site, Materials Disposal Area B (MDA-B), into a safe posture so it was well protected during the fire, but also allowed us to resume work quickly," said Project Director Al Chaloupka. Protecting Recovery Act Cleanup Site During Massive Wildfire More Documents & Publications Los Alamos Lab Completes Excavation of Waste Disposal Site Used in the 1940s

209

Power-Demand Routing in massive geo-distributed systems  

E-Print Network (OSTI)

There is an increasing trend toward massive, geographically distributed systems. The largest Internet companies operate hundreds of thousands of servers in multiple geographic locations, and are growing at a fast clip. A ...

Qureshi, Asfandyar

2010-01-01T23:59:59.000Z

210

Architectures massivement parallèles et vision artificielle bas-niveau.  

E-Print Network (OSTI)

??Ce travail de thèse étudie l'apport à la vision bas-niveau des architectures de calcul massivement parallèles. Nous reprenons l'évolution récente de l'architecture des ordinateurs, en… (more)

Plyer, Aurélien

2013-01-01T23:59:59.000Z

211

Massive Cement Pour into Hanford Site Nuclear Facility Underway: Recovery  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Massive Cement Pour into Hanford Site Nuclear Facility Underway: Massive Cement Pour into Hanford Site Nuclear Facility Underway: Recovery Act Funding Puts U Canyon in Home Stretch of Demolition Preparations Massive Cement Pour into Hanford Site Nuclear Facility Underway: Recovery Act Funding Puts U Canyon in Home Stretch of Demolition Preparations June 14, 2011 - 12:00pm Addthis Media Contacts Andre Armstrong, CH2M HILL Plateau Remediation Company (509) 376-6773 Andre_L_Armstrong@rl.gov Geoff Tyree, DOE (509) 376-4171 Geoffrey.Tyree@rl.doe.gov RICHLAND, Wash. - Hanford workers are pouring enough cement-like material to fill six Olympic-size wimming pools in one of the U.S. Department of Energy's (DOE) largest nuclear facilities at the Hanford Site in southeast Washington State to prepare the massive building for demolition.

212

Noncontiguous locking techniques for parallel file systems  

Science Conference Proceedings (OSTI)

Many parallel scientific applications use high-level I/O APIs that offer atomic I/O capabilities. Atomic I/O in current parallel file systems is often slow when multiple processes simultaneously access interleaved, shared files. Current atomic I/O solutions ...

Avery Ching; Wei-keng Liao; Alok Choudhary; Robert Ross; Lee Ward

2007-11-01T23:59:59.000Z

213

Graph theoretic approach to parallel gene assembly  

Science Conference Proceedings (OSTI)

We study parallel complexity of signed graphs motivated by the highly complex genetic recombination processes in ciliates. The molecular gene assembly operations have been modeled by operations of signed graphs, i.e., graphs where the vertices have a ... Keywords: Double-split graphs, Gene assembly, Local complement, Parallel assembly, Perfect matching, Signed graphs, Split graphs

Tero Harju; Chang Li; Ion Petre

2008-11-01T23:59:59.000Z

214

Evaluating Parallel I/O Energy Efficiency  

Science Conference Proceedings (OSTI)

Energy efficiency and parallel I/O performance are two primary constraints in high performance computing (HPC). Large scale computing systems consume vast amounts of energy and require scalable I/O performance to meet the needs of a broad spectrum of ... Keywords: Energy efficiency, Parallel I/O, DVFS

Rong Ge

2010-12-01T23:59:59.000Z

215

Human judgements in parallel treebank alignment  

Science Conference Proceedings (OSTI)

We have built a parallel treebank that includes word and phrase alignment. The alignment information was manually checked using a graphical tool that allows the annotator to view a pair of trees from parallel sentences. We found the compilation of clear ...

Martin Volk; Torsten Marek; Yvonne Samuelsson

2008-08-01T23:59:59.000Z

216

Visualizing structural properties of irregular parallel computations  

Science Conference Proceedings (OSTI)

An important task in parallel programming is the appropriate distribution of work on the processors. This distribution is usually dynamically changing and hard to predict, further it is very sensitive to the change of parameters. Even with advanced analysis ... Keywords: interactive performance tuning, visualization of parallel execution graphs

Wolfgang Blochinger; Michael Kaufmann; Martin Siebenhaller

2005-05-01T23:59:59.000Z

217

Automatic multilevel parallelization using OpenMP  

Science Conference Proceedings (OSTI)

In this paper we describe the extension of the CAPO parallelization support tool to support multilevel parallelism based on OpenMP directives. CAPO generates OpenMP directives with extensions supported by the NanosCompiler to allow for directive nesting ...

Haoqiang Jin; Gabriele Jost; Jerry Yan; Eduard Ayguade; Marc Gonzalez; Xavier Martorell

2003-04-01T23:59:59.000Z

218

Explicit implementation of a parallel dictionary  

E-Print Network (OSTI)

This report gives a complete implementation of a parallel dictionary based on 2-3 trees, using the parallel PRAM programming language fork. The implementations include procedures for creating and manipulating dictionary items by individual processors, searching in dictionaries, and parallel procedures for inserting and deleting collections of items. Procedures implementing parallel dictionary constructors and destructors are also provided. The implementations use the special fork constructs fork, for forming smaller groups of synchronously executing processors, and farm, designating an asynchronous context where strict statement level synchrony need not be enforced by the compiler. Both constructs add to the expressiveness and efficiency of the language. The parallel dictionary is a classical example of the use of the pipelining technique. Based on the concrete implementations given, a new language construct for implementing pipelined algorithms is proposed. Initial measurements performed using a simulator for the SB-PRAM being built at the University of Saarbrucken shows that the parallel incremental insertion and deletion operations are expensive compared to the batch operations of dictionary construction and destruction. An efficient parallel dictionary should therefore use the incremental operations only when the existing dictionary is large compared to the number of items that is to be inserted or deleted. More careful experiments are needed to determine when to switch. The parallel dictionary is part of the PAD library of PRAM algorithms and data structures.

Jesper Larsson Träff

1995-01-01T23:59:59.000Z

219

Parallel evolutionary computation in bioinformatics applications  

Science Conference Proceedings (OSTI)

A large number of optimization problems within the field of Bioinformatics require methods able to handle its inherent complexity (e.g. NP-hard problems) and also demand increased computational efforts. In this context, the use of parallel architectures ... Keywords: Aspect oriented programming, Bioinformatics, Evolutionary computation, Parallel software development

Jorge Pinho; JoãO Luis Sobral; Miguel Rocha

2013-05-01T23:59:59.000Z

220

Broadcasting a message in a parallel computer  

DOE Patents (OSTI)

Methods, systems, and products are disclosed for broadcasting a message in a parallel computer. The parallel computer includes a plurality of compute nodes connected together using a data communications network. The data communications network optimized for point to point data communications and is characterized by at least two dimensions. The compute nodes are organized into at least one operational group of compute nodes for collective parallel operations of the parallel computer. One compute node of the operational group assigned to be a logical root. Broadcasting a message in a parallel computer includes: establishing a Hamiltonian path along all of the compute nodes in at least one plane of the data communications network and in the operational group; and broadcasting, by the logical root to the remaining compute nodes, the logical root's message along the established Hamiltonian path.

Berg, Jeremy E. (Rochester, MN); Faraj, Ahmad A. (Rochester, MN)

2011-08-02T23:59:59.000Z

Note: This page contains sample records for the topic "massively parallel microcell-based" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Broadcasting a message in a parallel computer  

Science Conference Proceedings (OSTI)

Methods, systems, and products are disclosed for broadcasting a message in a parallel computer. The parallel computer includes a plurality of compute nodes connected together using a data communications network. The data communications network optimized for point to point data communications and is characterized by at least two dimensions. The compute nodes are organized into at least one operational group of compute nodes for collective parallel operations of the parallel computer. One compute node of the operational group assigned to be a logical root. Broadcasting a message in a parallel computer includes: establishing a Hamiltonian path along all of the compute nodes in at least one plane of the data communications network and in the operational group; and broadcasting, by the logical root to the remaining compute nodes, the logical root's message along the established Hamiltonian path.

Berg, Jeremy E. (Rochester, MN); Faraj, Ahmad A. (Rochester, MN)

2011-08-02T23:59:59.000Z

222

Parallel Implementations of an ILP system  

E-Print Network (OSTI)

Recently, researchers have tried to apply ILP to KDD because ILP enlarges the applicability of Machine Learning to cover KDD and Data Mining: it enables them to learn from multiple relational tables. Many scientific discovery systems are motivated from the desire to deal with larger databases. However the larger the databases are, the more computational power we need. Parallel computing is a possible solution to this problem. This research also aims to implement QUINLAN 's Foil in parallel. Foil finds definitions of relations using other relations in background knowledge with a top-down approach. There are two approaches to designing parallel algorithms for inductive learning, the search space parallel approach and the data parallel approach. In ILP data sets consist of training sets and background knowledge. Thus we examine three approaches, to part the search space, the training set, and the background knowledge. We experimented on FUJITSU AP3000 to compare among these approaches. Ex...

Tohgoroh MATSUI; Nobuhiro INUZUKA; Hirohisa SEKI; Hidenori ITOH

1998-01-01T23:59:59.000Z

223

Massively Multi-core Acceleration of a Document-Similarity Classifier to Detect Web Attacks  

Science Conference Proceedings (OSTI)

This paper describes our approach to adapting a text document similarity classifier based on the Term Frequency Inverse Document Frequency (TFIDF) metric to two massively multi-core hardware platforms. The TFIDF classifier is used to detect web attacks in HTTP data. In our parallel hardware approaches, we design streaming, real time classifiers by simplifying the sequential algorithm and manipulating the classifier's model to allow decision information to be represented compactly. Parallel implementations on the Tilera 64-core System on Chip and the Xilinx Virtex 5-LX FPGA are presented. For the Tilera, we employ a reduced state machine to recognize dictionary terms without requiring explicit tokenization, and achieve throughput of 37MB/s at slightly reduced accuracy. For the FPGA, we have developed a set of software tools to help automate the process of converting training data to synthesizable hardware and to provide a means of trading off between accuracy and resource utilization. The Xilinx Virtex 5-LX implementation requires 0.2% of the memory used by the original algorithm. At 166MB/s (80X the software) the hardware implementation is able to achieve Gigabit network throughput at the same accuracy as the original algorithm.

Ulmer, C; Gokhale, M; Top, P; Gallagher, B; Eliassi-Rad, T

2010-01-14T23:59:59.000Z

224

Evaluating the Performance of Parallel Programs in a Pseudo-Parallel MPI Environment  

E-Print Network (OSTI)

OF PAPER Evaluating the Performance of Parallel Programs in a Pseudo-Parallel MPI Environment By Erik Demaine This paper presents a system for use with the message-passing standard called MPI (Message Passing Interface) that provides a means of automatically simulating a distributed-memory parallel program. This allows one to evaluate a parallel algorithm without the use of a parallel computer. The system consists of three parts: the network evaluator, logging library, and simulator. The network evaluator is a parallel program that evaluates the network speed of a distributed-memory parallel computer. The logging library, when used, automatically logs the message-passing activity of the running program. The logs are designed so that running the "processors" on a uniprocessor workstation does not affect the contents. The simulator is a serial program that reads a log generated by the logging library and timing results from the network evaluator, and simulates the execution of the parall...

Erik Demaine

1996-01-01T23:59:59.000Z

225

Xyce parallel electronic simulator : users' guide.  

Science Conference Proceedings (OSTI)

This manual describes the use of the Xyce Parallel Electronic Simulator. Xyce has been designed as a SPICE-compatible, high-performance analog circuit simulator, and has been written to support the simulation needs of the Sandia National Laboratories electrical designers. This development has focused on improving capability over the current state-of-the-art in the following areas: (1) Capability to solve extremely large circuit problems by supporting large-scale parallel computing platforms (up to thousands of processors). Note that this includes support for most popular parallel and serial computers; (2) Improved performance for all numerical kernels (e.g., time integrator, nonlinear and linear solvers) through state-of-the-art algorithms and novel techniques. (3) Device models which are specifically tailored to meet Sandia's needs, including some radiation-aware devices (for Sandia users only); and (4) Object-oriented code design and implementation using modern coding practices that ensure that the Xyce Parallel Electronic Simulator will be maintainable and extensible far into the future. Xyce is a parallel code in the most general sense of the phrase - a message passing parallel implementation - which allows it to run efficiently on the widest possible number of computing platforms. These include serial, shared-memory and distributed-memory parallel as well as heterogeneous platforms. Careful attention has been paid to the specific nature of circuit-simulation problems to ensure that optimal parallel efficiency is achieved as the number of processors grows. The development of Xyce provides a platform for computational research and development aimed specifically at the needs of the Laboratory. With Xyce, Sandia has an 'in-house' capability with which both new electrical (e.g., device model development) and algorithmic (e.g., faster time-integration methods, parallel solver algorithms) research and development can be performed. As a result, Xyce is a unique electrical simulation capability, designed to meet the unique needs of the laboratory.

Mei, Ting; Rankin, Eric Lamont; Thornquist, Heidi K.; Santarelli, Keith R.; Fixel, Deborah A.; Coffey, Todd Stirling; Russo, Thomas V.; Schiek, Richard Louis; Warrender, Christina E.; Keiter, Eric Richard; Pawlowski, Roger Patrick

2011-05-01T23:59:59.000Z

226

Creating a Parallel Version of VisIt for Microsoft Windows  

Science Conference Proceedings (OSTI)

VisIt is a popular, free interactive parallel visualization and analysis tool for scientific data. Users can quickly generate visualizations from their data, animate them through time, manipulate them, and save the resulting images or movies for presentations. VisIt was designed from the ground up to work on many scales of computers from modest desktops up to massively parallel clusters. VisIt is comprised of a set of cooperating programs. All programs can be run locally or in client/server mode in which some run locally and some run remotely on compute clusters. The VisIt program most able to harness today's computing power is the VisIt compute engine. The compute engine is responsible for reading simulation data from disk, processing it, and sending results or images back to the VisIt viewer program. In a parallel environment, the compute engine runs several processes, coordinating using the Message Passing Interface (MPI) library. Each MPI process reads some subset of the scientific data and filters the data in various ways to create useful visualizations. By using MPI, VisIt has been able to scale well into the thousands of processors on large computers such as dawn and graph at LLNL. The advent of multicore CPU's has made parallelism the 'new' way to achieve increasing performance. With today's computers having at least 2 cores and in many cases up to 8 and beyond, it is more important than ever to deploy parallel software that can use that computing power not only on clusters but also on the desktop. We have created a parallel version of VisIt for Windows that uses Microsoft's MPI implementation (MSMPI) to process data in parallel on the Windows desktop as well as on a Windows HPC cluster running Microsoft Windows Server 2008. Initial desktop parallel support for Windows was deployed in VisIt 2.4.0. Windows HPC cluster support has been completed and will appear in the VisIt 2.5.0 release. We plan to continue supporting parallel VisIt on Windows so our users will be able to take full advantage of their multicore resources.

Whitlock, B J; Biagas, K S; Rawson, P L

2011-12-07T23:59:59.000Z

227

Optimal parallel scheduling of Gaussian elimination DAGs  

SciTech Connect

A parallel algorithm for Gaussian elimination (GE) is described which solves a linear system of size n using m>n parallel processors and a shared random access memory. Converting the serial GE algorithm to parallel form involves scheduling its computation DAG (direct acyclic graphs) on m processors. A lower bound for schedule length is established for dense GE DAGs, and it is proved that the proposed algorithm produces schedules which achieve these bounds. Finally, the construction and execution of the schedule are incorporated into a single concurrent program, which is shown to run in optimal time. 17 references.

Srinivas, M.A.

1983-12-01T23:59:59.000Z

228

Distributed parallel messaging for multiprocessor systems  

SciTech Connect

A method and apparatus for distributed parallel messaging in a parallel computing system. The apparatus includes, at each node of a multiprocessor network, multiple injection messaging engine units and reception messaging engine units, each implementing a DMA engine and each supporting both multiple packet injection into and multiple reception from a network, in parallel. The reception side of the messaging unit (MU) includes a switch interface enabling writing of data of a packet received from the network to the memory system. The transmission side of the messaging unit, includes switch interface for reading from the memory system when injecting packets into the network.

Chen, Dong; Heidelberger, Philip; Salapura, Valentina; Senger, Robert M; Steinmacher-Burrow, Burhard; Sugawara, Yutaka

2013-06-04T23:59:59.000Z

229

Generating OpenMP code using an interactive parallelization environment  

Science Conference Proceedings (OSTI)

Code parallelization using OpenMP for shared memory systems is relatively easier than using message passing for distributed memory systems. Despite this, it is still a challenge to use OpenMP to parallelize application codes in a way that yields effective ... Keywords: code parallelization tools, interactive parallelization environment, openMP code generation, parallel debugger

C. S. Ierotheou; H. Jin; G. Matthews; S. P. Johnson; R. Hood

2005-10-01T23:59:59.000Z

230

Data-only flattening for nested data parallelism  

Science Conference Proceedings (OSTI)

Data parallelism has proven to be an effective technique for high-level programming of a certain class of parallel applications, but it is not well suited to irregular parallel computations. Blelloch and others proposed nested data parallelism ... Keywords: compilers, flattening, multicore, nesl, nested data parallelism

Lars Bergstrom; Matthew Fluet; Mike Rainey; John Reppy; Stephen Rosen; Adam Shaw

2013-08-01T23:59:59.000Z

231

Parallel performance prediction using lost cycles analysis  

Science Conference Proceedings (OSTI)

Most performance debugging and tuning of parallel programs is based on the "measure-modify" approach, which is heavily dependent on detailed measurements of programs during execution. This approach is extremely time-consuming and does not lend itself ...

Mark E. Crovella; Thomas J. LeBlanc

1994-11-01T23:59:59.000Z

232

Earthquake ground motion modeling on parallel computers  

Science Conference Proceedings (OSTI)

We describe the design and discuss the performance of a parallel elastic wave propagation simulator that is being used to model and study earthquake-induced ground motion in large sedimentary basins. The components of the system include mesh generators, ...

Hesheng Bao; Jacobo Bielak; Omar Ghattas; Loukas F. Kallivokas; David R. O'Hallaron; Jonathan R. Shewchuk; Jifeng Xu

1996-11-01T23:59:59.000Z

233

Efficient system-enforced deterministic parallelism  

Science Conference Proceedings (OSTI)

Deterministic execution offers many benefits for debugging, fault tolerance, and security. Current methods of executing parallel programs deterministically, however, often incur high costs, allow misbehaved software to defeat repeatability, and transform ...

Amittai Aviram; Shu-Chun Weng; Sen Hu; Bryan Ford

2010-10-01T23:59:59.000Z

234

Parallel Displacement Decomposition Solvers for Elasticity Problems  

Science Conference Proceedings (OSTI)

This article describes the displacement decomposition and its benefits for the parallelization of the preconditioned conjugate gradient method for finite element elasticity problems. It deals with both the fixed and variable preconditioning based on ...

Radim Blaheta; Ondrej Jakl; Jiri Stary

2001-09-01T23:59:59.000Z

235

Provably Efficient Adaptive Scheduling for Parallel Jobs  

E-Print Network (OSTI)

Scheduling competing jobs on multiprocessors has always been an important issue for parallel and distributed systems. The challenge is to ensure global, system-wide efficiency while offering a level of fairness to user ...

He, Yuxiong

236

Components of systems software for parallel systems  

Science Conference Proceedings (OSTI)

Systems software for clusters and other parallel systems affects multiple types of users. End users interact with it to submit and interact with application jobs and to avail themselves of scalable system tools. Systems administrators interact with it ...

Ewing Lusk

2005-09-01T23:59:59.000Z

237

Data Distribution for Parallel CORBA Objects  

Science Conference Proceedings (OSTI)

The design of application for Computational Grids relies partly on communication paradigms. In most of the Grid experiments, message-passing has been the main paradigm either to let several processes from a single parallel application to exchange data ...

Tsunehiko Kamachi; Thierry Priol; Christophe René

2000-08-01T23:59:59.000Z

238

Parallel programming with PCN. Revision 1  

SciTech Connect

PCN is a system for developing and executing parallel programs. It comprises a high-level programming language, tools for developing and debugging programs in this language, and interfaces to Fortran and C that allow the reuse of existing code in multilingual parallel programs. Programs developed using PCN are portable across many different workstations, networks, and parallel computers. This document provides all the information required to develop parallel programs with the PCN programming system. In includes both tutorial and reference material. It also presents the basic concepts that underly PCN, particularly where these are likely to be unfamiliar to the reader, and provides pointers to other documentation on the PCN language, programming techniques, and tools. PCN is in the public domain. The latest version of both the software and this manual can be obtained by anonymous FTP from Argonne National Laboratory in the directory pub/pcn at info.mcs.anl.gov (c.f. Appendix A).

Foster, I.; Tuecke, S.

1991-12-01T23:59:59.000Z

239

Parallel Algorithms for Image Processing on OMC  

Science Conference Proceedings (OSTI)

The author studies a class of VLSI organizations with optical interconnects for fast solutions to several image processing tasks. The organization and operation of these architectures are based on a generic model called OMC, which is used to understand ... Keywords: OMC, computational complexity, computational limits, computerised picture processing, constant time algorithms, fine grain image computing, free space optics, generic model, image processing, optical information processing, optical interconnects, parallel algorithms, parallel algorithms.

Mary Mehrnoosh Eshaghian

1991-07-01T23:59:59.000Z

240

Ball State building massive geothermal system | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Ball State building massive geothermal system Ball State building massive geothermal system Ball State building massive geothermal system March 19, 2010 - 5:47pm Addthis Workers drill boreholes for a geothermal heating and cooling system at Ball State University’s campus in Muncie, Ind. | Photo courtesy of Ball State University Workers drill boreholes for a geothermal heating and cooling system at Ball State University's campus in Muncie, Ind. | Photo courtesy of Ball State University Paul Lester Communications Specialist for the Office of Energy Efficiency and Renewable Energy Ball State University is building America's largest ground source district geothermal heating and cooling system. The new operation will save the school millions of dollars, slash greenhouse gases and create jobs. The project will also "expand how America will define the use of

Note: This page contains sample records for the topic "massively parallel microcell-based" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Ball State building massive geothermal system | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Ball State building massive geothermal system Ball State building massive geothermal system Ball State building massive geothermal system March 19, 2010 - 5:47pm Addthis Workers drill boreholes for a geothermal heating and cooling system at Ball State University’s campus in Muncie, Ind. | Photo courtesy of Ball State University Workers drill boreholes for a geothermal heating and cooling system at Ball State University's campus in Muncie, Ind. | Photo courtesy of Ball State University Paul Lester Communications Specialist, Office of Energy Efficiency and Renewable Energy Ball State University is building America's largest ground source district geothermal heating and cooling system. The new operation will save the school millions of dollars, slash greenhouse gases and create jobs. The project will also "expand how America will define the use of

242

Massive Soil Cleanup Effort Concludes at Hanford - Recovery Act Funding  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Massive Soil Cleanup Effort Concludes at Hanford - Recovery Act Massive Soil Cleanup Effort Concludes at Hanford - Recovery Act Funding Pays for Safe Disposal of 20,000 Truckloads of Soil Massive Soil Cleanup Effort Concludes at Hanford - Recovery Act Funding Pays for Safe Disposal of 20,000 Truckloads of Soil August 11, 2011 - 12:00pm Addthis Media Contacts Andre Armstrong, CH2M HILL Andre_L_Armstrong@rl.gov 509-376-6773 Geoff Tyree, DOE Geoffrey.Tyree@rl.doe.gov 509-376-4171 RICHLAND, Wash. - U.S. Department of Energy contractor CH2M HILL Plateau Remediation Company removed nearly half a million tons of contaminated soil over the last two years using American Recovery and Reinvestment Act funding at the Hanford Site in southeast Washington State. Workers shipped more than 20,000 truckloads of contaminated soil excavated

243

Massive Stars in Colliding Wind Systems: the GLAST Perspective  

SciTech Connect

Colliding winds of massive stars in binary systems are considered as candidate sites of high-energy non-thermal photon emission. They are already among the suggested counterparts for a few individual unidentified EGRET sources, but may constitute a detectable source population for the GLAST observatory. The present work investigates such population study of massive colliding wind systems at high-energy gamma-rays. Based on the recent detailed model (Reimer et al. 2006) for non-thermal photon production in prime candidate systems, we unveil the expected characteristics of this source class in the observables accessible at LAT energies. Combining the broadband emission model with the presently cataloged distribution of such systems and their individual parameters allows us to conclude on the expected maximum number of LAT-detections among massive stars in colliding wind binary systems.

Reimer, Anita; Reimer, Olaf; /Stanford U., HEPL /KIPAC, Menlo Park

2011-11-29T23:59:59.000Z

244

The Dense Stellar Systems Around Galactic Massive Black Holes  

E-Print Network (OSTI)

The central regions of galaxies show the presence of massive black holes and/or dense stellar systems. The question about their modes of formation is still under debate. A likely explanation of the formation of the central dense stellar systems in both spiral and elliptical galaxies is based on the orbital decay of massive globular clusters in the central region of galaxies due to kinetic energy dissipation by dynamical friction. Their merging leads to the formation of a nuclear star cluster, like that of the Milky Way, where a massive black hole (Sgr A*) is also present. Actually, high precision N-body simulations (Antonini, Capuzzo-Dolcetta et al. 2012, ApJ, 750, 111) show a good fit to the observational characteristics of the Milky Way nuclear cluster, giving further reliability to the cited `migratory' model for the formation of compact systems in the inner galaxy regions.

Capuzzo-Dolcetta, R; Spera, M

2013-01-01T23:59:59.000Z

245

Parallel supercomputing: Advanced methods, algorithms, and software for large-scale linear and nonlinear problems. Final report, August 15, 1993--February 28, 1996  

SciTech Connect

This report gives a quick description of progress on methods, algorithms and software for large-scale parallel supercomputer applications. Focus is on large-scale applications of interest to DOE such as coupled viscous flow and heat or mass transport, and energy-related applications such as 3D petroleum and gas reservoir simulations on massively parallel systems. The interdisciplinary collaboration has been effective since it enhances the development of new iterative schemes for complex problems important to DOE: for example, significant advanced were made with modified forms of generalized gradient and multigrid methods for viscous flow and reservoir problems.

Carey, G.F. [Texas Univ., Austin, TX (United States). Inst. for Computational and Applied Mathematics; Young, D.M. [Texas Univ., Austin, TX (United States). Center for Numerical Analysis

1996-07-01T23:59:59.000Z

246

Energy momentum flows for the massive vector field  

E-Print Network (OSTI)

We present a causal trajectory interpretation for the massive vector field, based on the flows of rest energy and a conserved density defined using the time-like eigenvectors and eigenvalues of the stress-energy-momentum tensor. This work extends our previous work which used a similar procedure for the scalar field. The massive, spin-one, complex vector field is discussed in detail and solutions are classified using the Pauli-Lubanski spin vector. The flows of energy-momentum are illustrated in a simple example of standing waves in a plane.

George Horton; Chris Dewdney

2006-09-26T23:59:59.000Z

247

Programming in Manticore, a heterogenous parallel functional language  

Science Conference Proceedings (OSTI)

The Manticore project is an effort to design and implement a new functional language for parallel programming. Unlike many earlier parallel languages, Manticore is a heterogeneous language that supports parallelism at multiple levels. Specifically, the ...

Matthew Fluet; Lars Bergstrom; Nic Ford; Mike Rainey; John Reppy; Adam Shaw; Yingqi Xiao

2009-05-01T23:59:59.000Z

248

NDSeq: runtime checking for nondeterministic sequential specifications of parallel correctness  

Science Conference Proceedings (OSTI)

We propose to specify the correctness of a program's parallelism using a sequential version of the program with controlled nondeterminism. Such a nondeterministic sequential specification allows (1) the correctness of parallel interference to ... Keywords: parallel correctness, serializability, specification

Jacob Burnim; Tayfun Elmas; George Necula; Koushik Sen

2011-06-01T23:59:59.000Z

249

Optimising Skeletal-Stream Parallelism on a BSP Computer  

Science Conference Proceedings (OSTI)

Stream parallelism allows parallel programs to exploit the potential of executing different parts of the computation on distinct input data items. Stream parallelism can also exploit the concurrent evaluation of the same function on different input items. ...

Andrea Zavanella

1999-08-01T23:59:59.000Z

250

Massive global ozone loss predicted following regional nuclear conflict  

E-Print Network (OSTI)

Massive global ozone loss predicted following regional nuclear conflict Michael J. Mills* , Owen B a chemistry-climate model and new estimates of smoke produced by fires in contemporary cities to calculate the impact on stratospheric ozone of a regional nuclear war between developing nuclear states involving 100

251

A note on positive energy of topologically massive gravity  

E-Print Network (OSTI)

I review how "classical SUGRA" embeddability establishes positive energy E for D=3 topologically massive gravity (TMG), with or without a cosmological term, a procedure familiar from D=4 Einstein gravity (GR). It also provides explicit expressions for E. In contrast to GR, E is not manifestly positive, due to the peculiar two-term nature of TMG.

Deser, S

2009-01-01T23:59:59.000Z

252

The Effect of Massive Neutrinos on Matter Power Spectrum  

E-Print Network (OSTI)

We investigate the impact of massive neutrinos on the distribution of matter in the semi-nonlinear regime (0.1eV-1.9 eV respectively. We also discuss the precision levels that future cosmological datasets would have to achieve in order to resolve between the normal and inverted neutrino mass hierarchies.

Agarwal, Shankar

2010-01-01T23:59:59.000Z

253

Parallelization of ITOUGH2 using PVM  

SciTech Connect

ITOUGH2 inversions are computationally intensive because the forward problem must be solved many times to evaluate the objective function for different parameter combinations or to numerically calculate sensitivity coefficients. Most of these forward runs are independent from each other and can therefore be performed in parallel. Message passing based on the Parallel Virtual Machine (PVM) system has been implemented into ITOUGH2 to enable parallel processing of ITOUGH2 jobs on a heterogeneous network of Unix workstations. This report describes the PVM system and its implementation into ITOUGH2. Instructions are given for installing PVM, compiling ITOUGH2-PVM for use on a workstation cluster, the preparation of an 1.TOUGH2 input file under PVM, and the execution of an ITOUGH2-PVM application. Examples are discussed, demonstrating the use of ITOUGH2-PVM.

Finsterle, Stefan

1998-10-01T23:59:59.000Z

254

Simulating the scheduling of parallel supercomputer applications  

SciTech Connect

An Event Driven Simulator for Evaluating Multiprocessing Scheduling (EDSEMS) disciplines is presented. The simulator is made up of three components: machine model; parallel workload characterization ; and scheduling disciplines for mapping parallel applications (many processes cooperating on the same computation) onto processors. A detailed description of how the simulator is constructed, how to use it and how to interpret the output is also given. Initial results are presented from the simulation of parallel supercomputer workloads using Dog-Eat-Dog,'' Family'' and Gang'' scheduling disciplines. These results indicate that Gang scheduling is far better at giving the number of processors that a job requests than Dog-Eat-Dog or Family scheduling. In addition, the system throughput and turnaround time are not adversely affected by this strategy. 10 refs., 8 figs., 1 tab.

Seager, M.K.; Stichnoth, J.M.

1989-09-19T23:59:59.000Z

255

Stiffness Analysis of Overconstrained Parallel Manipulators  

E-Print Network (OSTI)

The paper presents a new stiffness modeling method for overconstrained parallel manipulators with flexible links and compliant actuating joints. It is based on a multidimensional lumped-parameter model that replaces the link flexibility by localized 6-dof virtual springs that describe both translational/rotational compliance and the coupling between them. In contrast to other works, the method involves a FEA-based link stiffness evaluation and employs a new solution strategy of the kinetostatic equations for the unloaded manipulator configuration, which allows computing the stiffness matrix for the overconstrained architectures, including singular manipulator postures. The advantages of the developed technique are confirmed by application examples, which deal with comparative stiffness analysis of two translational parallel manipulators of 3-PUU and 3-PRPaR architectures. Accuracy of the proposed approach was evaluated for a case study, which focuses on stiffness analysis of Orthoglide parallel manipulator.

Pashkevich, Anatoly; Wenger, Philippe; 10.1016/j.mechmachtheory.2008.05.017

2009-01-01T23:59:59.000Z

256

Complementing user-level coarse-grain parallelism with implicit speculative parallelism  

Science Conference Proceedings (OSTI)

Multi-core and many-core systems are the norm in contemporary processor technology and are expected to remain so for the foreseeable future. Programs using parallel programming primitives like PThreads or OpenMP often exploit coarse-grain ... Keywords: many-core architecture, thread-level parallelism, thread-level speculation

Nikolas Ioannou; Marcelo Cintra

2011-12-01T23:59:59.000Z

257

A Programmable Preprocessor for Parallelizing Fortran-90  

SciTech Connect

A programmable preprocessor that generates portable and efficient parallel Fortran-90 code has been successfully used in the development of a variety of environmental transport simulators for the Department of Energy. The tool provides the basic functionality of a traditional preprocessor where directives are embedded in a serial Fortran program and interpreted by the preprocessor to produce parallel Fortran code with MPI calls. The unique aspect of this work is that the user can make additions to, or modify, these directives. The directives reside in a preprocessor library and changes to this library can range from small changes to customize an existing library, to larger changes for porting a library, to completely replacing the library. The preprocessor is programmed with a library of directives written in a C-like language, called DL, that has added support for manipulating Fortran code fragments. The primary benefits to the user are twofold: It is fairly easy for any user to generate efficient, parallel code from Fortran-90 with embedded directives, and the long term viability of the user?s software is guaranteed. This is because the source code will always run on a serial machine (the directives are transparent to standard Fortran compilers), and the preprocessor library can be modified to work with different hardware and software environments. A 4000 line preprocessor library has been written and used to parallelize roughly 50,000 lines of groundwater modeling code. The programs have been ported to a wide range of parallel architectures. Performance of these programs is similar to programs explicitly written for a parallel machine. Binaries of the preprocessor core, as well as the preprocessor library source code used in our groundwater modeling codes are currently available.

Rosing, Matthew; Yabusaki, Steven B.

1999-07-01T23:59:59.000Z

258

A PARALLEL EXTENSION OF THE UAL ENVIRONMENT.  

SciTech Connect

The deployment of the Unified Accelerator Library (UAL) environment on the parallel cluster is presented. The approach is based on the Message-Passing Interface (MPI) library and the Perl adapter that allows one to control and mix together the existing conventional UAL components with the new MPI-based parallel extensions. In the paper, we provide timing results and describe the application of the new environment to the SNS Ring complex beam dynamics studies, particularly, simulations of several physical effects, such as space charge, field errors, fringe fields, and others.

MALITSKY, N.; SHISHLO, A.

2001-06-18T23:59:59.000Z

259

Temporal fringe pattern analysis with parallel computing  

SciTech Connect

Temporal fringe pattern analysis is invaluable in transient phenomena studies but necessitates long processing times. Here we describe a parallel computing strategy based on the single-program multiple-data model and hyperthreading processor technology to reduce the execution time. In a two-node cluster workstation configuration we found that execution periods were reduced by 1.6 times when four virtual processors were used. To allow even lower execution times with an increasing number of processors, the time allocated for data transfer, data read, and waiting should be minimized. Parallel computing is found here to present a feasible approach to reduce execution times in temporal fringe pattern analysis.

Tuck Wah Ng; Kar Tien Ang; Argentini, Gianluca

2005-11-20T23:59:59.000Z

260

Exploiting hierarchical parallelisms for molecular dynamics simulation on multicore clusters  

Science Conference Proceedings (OSTI)

We have developed a scalable hierarchical parallelization scheme for molecular dynamics (MD) simulation on multicore clusters. The scheme explores multilevel parallelism combining: (1) Internode parallelism using spatial decomposition via message passing; ... Keywords: Molecular dynamics simulation, Multicore cluster, Scalable hierarchical parallelization scheme, Single instruction multiple data

Liu Peng; Manaschai Kunaseth; Hikmet Dursun; Ken-Ichi Nomura; Weiqiang Wang; Rajiv K. Kalia; Aiichiro Nakano; Priya Vashishta

2011-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "massively parallel microcell-based" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Parallel computation for shallow water flow: a domain decomposition approach  

Science Conference Proceedings (OSTI)

Keywords: additive Schwarz preconditioning, domain decomposition, finite elements, parallelization, shallow water

L. Paglieri; D. Ambrosi; L. Formaggia; A. Quarteroni; A. L. Scheinine

1997-09-01T23:59:59.000Z

262

Object oriented parallelisation of graph algorithms using parallel iterator  

Science Conference Proceedings (OSTI)

Multi-core machines are becoming widely used which, as a consequence, forces parallel computing to move from research labs to being adopted everywhere. Due to the fact that developing parallel code is a significantly complex process, the main focus of ... Keywords: graph algorithms, object oriented parallelisation, parallel computing, parallel iterator

Lama Akeila; Oliver Sinnen; Wafaa Humadi

2010-01-01T23:59:59.000Z

263

PADMA: PArallel Data Mining Agents for scalable text classification  

Science Conference Proceedings (OSTI)

This paper introduces PADMA (PArallel Data Mining Agents), a parallel agent based system for scalable text classification. PADMA contains modules for (1) parallel data accessing operations, (2) parallel hierarchical clustering, and (3) web-based data visualization. This paper introduces the general architecture of PADMA and presents a detailed description of its different modules.

Kargupta, H.; Hamzaoglu, I.; Stafford, B. [and others

1997-03-01T23:59:59.000Z

264

Techniques for debugging parallel programs with flowback analysis  

Science Conference Proceedings (OSTI)

Keywords: debugging, flowback analysis, incremental tracing, parallel program, program dependence graph, semantic analysis

Jong-Deok Choi; Barton P. Miller; Robert H. B. Netzer

1991-10-01T23:59:59.000Z

265

Practical parallel remote method invocation for the Babel compiler  

Science Conference Proceedings (OSTI)

Parallel components are types of software components that contain Single Program Multiple Data (SPMD) parallel code and are used and defined by the Common Component Architecture (CCA) component model. Parallel Remote Method Invocation (PRMI) defines ... Keywords: IDL compiler, parallel remote method invocation

Kostadin Damevski; Keming Zhang; Steven Parker

2007-10-01T23:59:59.000Z

266

Approximate parallel simulation of web search engines  

Science Conference Proceedings (OSTI)

Large scale Web search engines are complex and highly optimized systems devised to operate on dedicated clusters of processors. Any, even a small, gain in performance is beneficial to economical operation given the large amount of hardware resources ... Keywords: discrete event simulation, parallel computation

Mauricio Marin, Veronica Gil-Costa, Carolina Bonacic, Roberto Solar

2013-05-01T23:59:59.000Z

267

From patterns to frameworks to parallel programs  

Science Conference Proceedings (OSTI)

Object-oriented programming, design patterns, and frameworks are abstraction techniques that have been used to reduce the complexity of sequential programming. This paper describes our approach of applying these three techniques to the more difficult ... Keywords: design patterns, object-oriented frameworks, parallel programming systems

S. MacDonald; J. Anvik; S. Bromling; J. Schaeffer; D. Szafron; K. Tan

2002-12-01T23:59:59.000Z

268

A Requirements Analysis for Parallel KDD Systems  

Science Conference Proceedings (OSTI)

The current generation of data mining tools have limited capacity and performance, since these tools tend to be sequential. This paper explores a migration path out of this bottleneck by considering an in tegrated hardware and softw are approach to parallelize ...

William Maniatty; Mohammed Javeed Zaki

2000-05-01T23:59:59.000Z

269

Aspects of Applicative Programming for Parallel Processing  

Science Conference Proceedings (OSTI)

Early results of a project on compiling stylized recursion into stackless iterative code are reviewed as they apply to a target environment with multiprocessing. Parallelism is possible in executing the compiled image of argument evaluation (collateral ... Keywords: suspensions, Compiling, functional combinations, Lisp, multiprocessing, recursion

D. P. Friedman; D. S. Wise

1978-04-01T23:59:59.000Z

270

The Parallelization of the Princeton Ocean Model  

Science Conference Proceedings (OSTI)

In this paper we present the parallel implementation of the Princeton Ocean Model (POM) using message passing. Domain decomposition techniques are used for the horizontal discretization whereas in the vertical direction each column per grid point is ... Keywords: domain decomposition, message passing, princeton ocean model

L. A. Boukas; N. Th. Mimikou; Nikolaos M. Missirlis; G. L. Mellor; A. Lascaratos; G. Korres

1999-08-01T23:59:59.000Z

271

Parallel multiscale simulations of a brain aneurysm  

Science Conference Proceedings (OSTI)

Cardiovascular pathologies, such as a brain aneurysm, are affected by the global blood circulation as well as by the local microrheology. Hence, developing computational models for such cases requires the coupling of disparate spatial and temporal scales ... Keywords: Atomistic-continuum coupling, Blood microrheology, Dissipative particle dynamics, Domain decomposition, Parallel computing, Spectral elements, Thrombosis

Leopold Grinberg, Dmitry A. Fedosov, George Em Karniadakis

2013-07-01T23:59:59.000Z

272

Message passing with parallel queue traversal  

SciTech Connect

In message passing implementations, associative matching structures are used to permit list entries to be searched in parallel fashion, thereby avoiding the delay of linear list traversal. List management capabilities are provided to support list entry turnover semantics and priority ordering semantics.

Underwood, Keith D. (Albuquerque, NM); Brightwell, Ronald B. (Albuquerque, NM); Hemmert, K. Scott (Albuquerque, NM)

2012-05-01T23:59:59.000Z

273

Parallel kinematic machine design with kinetostatic model  

Science Conference Proceedings (OSTI)

In this paper, a new method – named lumped kinetostatic modeling – to analyze the effect of the link flexibility on the mechanism's stiffness is provided. A new type of mechanism whose degree of freedom (dof) is dependent on a passive constraining ... Keywords: Kinetostatic model, Link flexibility, Parallel mechanisms, Precision optimization

Dan Zhang; Clément M. Gosselin

2002-07-01T23:59:59.000Z

274

Multithread parallelization of Lepp-bisection algorithms  

Science Conference Proceedings (OSTI)

Longest edge (nested) algorithms for triangulation refinement in two dimensions are able to produce hierarchies of quality and nested irregular triangulations as needed both for adaptive finite element methods and for multigrid methods. They can be formulated ... Keywords: Finite element method, Lepp-bisection algorithm, Longest edge bisection, Parallel multithread refinement, Triangulation refinement

Maria-Cecilia Rivara; Pedro Rodriguez; Rafael Montenegro; Gaston Jorquera

2012-04-01T23:59:59.000Z

275

Parallel simulation of software defined networks  

Science Conference Proceedings (OSTI)

Existing network architectures fall short when handling networking trends, e.g., mobility, server virtualization, and cloud computing, as well as market requirements with rapid changes. Software-defined networking (SDN) is designed to transform network ... Keywords: parallel discrete event simulation, software-defined networking

Dong Jin, David M. Nicol

2013-05-01T23:59:59.000Z

276

Sonderforschungsbereich 393 Parallele Numerische Simulation fur  

E-Print Network (OSTI)

393 NUMERISCHE PARALLELE SIMULATION SN ARBEITS­ UND ERGEBNISBERICHT 2004 ­ 2005 #12;#12;ARBEITS­ UND ERGEBNISBERICHT 2004­2005 SFB 393 Deutsche Forschungsgemeinschaft -- Sonderforschungsbereiche -- ¨uber Magnifizenz SIMULATION SN #12;#12;Inhaltsverzeichnis 1 Allgemeiner Teil/Zusammenfassung 5 1.1 Wissenschaftliche

Chemnitz, Technische Universität

277

A classification of scientific visualization algorithms for massive threading  

Science Conference Proceedings (OSTI)

As the number of cores in processors increase and accelerator architectures are becoming more common, an ever greater number of threads is required to achieve full processor utilization. Our current parallel scientific visualization codes rely on partitioning ...

Kenneth Moreland, Berk Geveci, Kwan-Liu Ma, Robert Maynard

2013-11-01T23:59:59.000Z

278

Parallel FE Electron-Photon Transport Analysis on 2-D Unstructured Mesh  

SciTech Connect

A novel solution method has been developed to solve the coupled electron-photon transport problem on an unstructured triangular mesh. Instead of tackling the first-order form of the linear Boltzmann equation, this approach is based on the second-order form in conjunction with the conventional multi-group discrete-ordinates approximation. The highly forward-peaked electron scattering is modeled with a multigroup Legendre expansion derived from the Goudsmit-Saunderson theory. The finite element method is used to treat the spatial dependence. The solution method is unique in that the space-direction dependence is solved simultaneously, eliminating the need for the conventional inner iterations, a method that is well suited for massively parallel computers.

Drumm, C.R.; Lorenz, J.

1999-03-02T23:59:59.000Z

279

Secretary Chu Announces New Institute to Help Scientists Improve Massive  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

New Institute to Help Scientists Improve New Institute to Help Scientists Improve Massive Data Set Research on DOE Supercomputers Secretary Chu Announces New Institute to Help Scientists Improve Massive Data Set Research on DOE Supercomputers March 29, 2012 - 2:48pm Addthis Washington D.C. - Energy Secretary Steven Chu today announced $5 million to establish the Scalable Data Management, Analysis and Visualization (SDAV) Institute as part of the Obama Administration's "Big Data Research and Development Initiative," which was announced this morning and takes aim at improving the nation's ability to extract knowledge and insights from large and complex collections of digital data. Led by the Energy Department's Lawrence Berkeley National Laboratory, the SDAV Institute will bring together the expertise of six national laboratories

280

Off-Criticality and the Massive Brownian Loop Soup  

E-Print Network (OSTI)

The Brownian loop soup is a conformally invariant Poissonian ensemble of loops in the plane recently introduced by Lawler and Werner. It has attracted significant attention for its connection to the Schramm-Loewner Evolution and Conformal Loop Ensembles and its consequent ability to describe the critical scaling limit of two-dimensional statistical mechanical models. In this paper, we introduce a natural "massive" (non-scale-invariant) version of the Brownian loop soup as a candidate to describe near-critical scaling limits, and study some of its properties, such as conformal covariance, exponential decay of correlations, and Hausdorff dimension. We also show that the massive Brownian loop soup arises as the near-critical scaling limit of a "gas" of random walk loops which is closely related to the discrete Gaussian free field.

Federico Camia

2013-09-24T23:59:59.000Z

Note: This page contains sample records for the topic "massively parallel microcell-based" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Geometric Massive Gravity in Multi-Connection Framework  

E-Print Network (OSTI)

What is the right way to interpret a massive graviton? We generalize the kinematical framework of general relativity to multiple connections. The average of the connections is itself a connection and plays the role of the canonical connection in standard General Relativity. At the level of dynamics, the simplest choice of the Einstein-Hilbert action is indistinguishable from the single-connection case. However, inspired by Weyl geometry, we show how one can construct massive gravity to all orders in perturbation theory compatible with the de Rham-Gabadadze-Tolley ghost-free model. We conclude that the mass of the graviton can be interpreted as a geometrical property of spacetime arising from two connections. Furthermore in the multi-connection framework there is no ambiguity in the definition of physical metric and consequently coupling to matter.

Nima Khosravi

2013-09-09T23:59:59.000Z

282

INTERNAL GRAVITY WAVES IN MASSIVE STARS: ANGULAR MOMENTUM TRANSPORT  

SciTech Connect

We present numerical simulations of internal gravity waves (IGW) in a star with a convective core and extended radiative envelope. We report on amplitudes, spectra, dissipation, and consequent angular momentum transport by such waves. We find that these waves are generated efficiently and transport angular momentum on short timescales over large distances. We show that, as in Earth's atmosphere, IGW drive equatorial flows which change magnitude and direction on short timescales. These results have profound consequences for the observational inferences of massive stars, as well as their long term angular momentum evolution. We suggest IGW angular momentum transport may explain many observational mysteries, such as: the misalignment of hot Jupiters around hot stars, the Be class of stars, Ni enrichment anomalies in massive stars, and the non-synchronous orbits of interacting binaries.

Rogers, T. M. [Department of Planetary Sciences, University of Arizona, Tucson, AZ 85719 (United States); Lin, D. N. C. [Astronomy and Astrophysics Department, University of California, Santa Cruz, CA 95064 (United States); McElwaine, J. N. [Swiss Federal Institute for Snow and Avalanche Research, 11 Fluelastrasse, Davos Dorf (Switzerland); Lau, H. H. B., E-mail: tami@lpl.arizona.edu, E-mail: lin@ucolick.org, E-mail: james.mcelwaine@slf.ch, E-mail: hblau@astro.uni-bonn.de [Argelander-Institut for Astronomie, Universit Bonn Auf dem Huegel 71, D-53121 Bonn (Germany)

2013-07-20T23:59:59.000Z

283

GRAVITATIONAL SLINGSHOT OF YOUNG MASSIVE STARS IN ORION  

SciTech Connect

The Orion Nebula Cluster (ONC) is the nearest region of massive star formation and thus a crucial testing ground for theoretical models. Of particular interest among the ONC's {approx}1000 members are: {theta}{sup 1} Ori C, the most massive binary in the cluster with stars of masses 38 and 9 M{sub Sun }; the Becklin-Neugebauer (BN) object, a 30 km s{sup -1} runaway star of {approx}8 M{sub Sun }; and the Kleinmann-Low (KL) nebula protostar, a highly obscured, {approx}15 M{sub Sun} object still accreting gas while also driving a powerful, apparently 'explosive' outflow. The unusual behavior of BN and KL is much debated: How did BN acquire its high velocity? How is this related to massive star formation in the KL nebula? Here, we report the results of a systematic survey using {approx}10{sup 7} numerical experiments of gravitational interactions of the {theta}{sup 1}C and BN stars. We show that dynamical ejection of BN from this triple system at its observed velocity leaves behind a binary with total energy and eccentricity matching those observed for {theta}{sup 1}C. Five other observed properties of {theta}{sup 1}C are also consistent with it having ejected BN and altogether we estimate that there is only a {approx}< 10{sup -5} probability that {theta}{sup 1}C has these properties by chance. We conclude that BN was dynamically ejected from the {theta}{sup 1}C system about 4500 years ago. BN then plowed through the KL massive star-forming core within the last 1000 years causing its recently enhanced accretion and outflow activity.

Chatterjee, Sourav; Tan, Jonathan C., E-mail: s.chatterjee@astro.ufl.edu, E-mail: jt@astro.ufl.edu [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States)

2012-08-01T23:59:59.000Z

284

Thermodynamics of the apparent horizon in massive cosmology  

E-Print Network (OSTI)

Applying Clausius relation with energy-supply defined by the unified first law of thermodynamics formalism to the apparent horizon of a massive cosmological model proposed lately, the corrected entropic formula of the apparent horizon is obtained with the help of the modified Friedmann equations. This entropy-area relation, together with the identified internal energy, verifies the first law of thermodynamics for the apparent horizon with a volume change term for consistency. On the other hand, by means of the corrected entropy-area formula and the Clausius relation $\\delta Q=T dS$, the modified Friedmann equations governing the dynamical evolution of the universe are reproduced with the known energy density and pressure of massive graviton. The integration constant is found to correspond to a cosmological term which could be absorbed into the energy density of matter. Having established the correspondence of massive cosmology with the unified first law of thermodynamics on the apparent horizon, the validity of the generalized second law of thermodynamics is also discussed by assuming the thermal equilibrium between the apparent horizon and the matter field bounded by the apparent horizon. It is found that, in the limit $H_c\\rightarrow 0$ which recovers the Minkowski reference metric solution in the flat case, the generalized second law of thermodynamics holds if $\\alpha_3+4\\alpha_4<0$. Apart from that, even for the simplest model of dRGT massive cosmology with $\\alpha_3=\\alpha_4=0$, the generalized second law of thermodynamics could be violated.

Hui Li; Yi Zhang

2013-04-17T23:59:59.000Z

285

Quantum Energy Inequality for the Massive Ising Model  

E-Print Network (OSTI)

A Quantum Energy Inequality (QEI) is derived for the massive Ising model, giving a state-independent lower bound on suitable averages of the energy density; the first QEI to be established for an interacting quantum field theory with nontrivial S-matrix. It is shown that the Ising model has one-particle states with locally negative energy densities, and that the energy density operator is not additive with respect to combination of one-particle states into multi-particle configurations.

Bostelmann, Henning; Fewster, Christopher J

2013-01-01T23:59:59.000Z

286

Black Holes in Born-Infeld Extended New Massive Gravity  

E-Print Network (OSTI)

In this paper we find different types of black holes for the Born-Infeld extended new massive gravity. Our solutions include (un)charged (A)dS warped black holes for four and six derivative expanded action. We also look at the black holes in unexpanded action. In each case we calculate the entropy, angular momentum and the mass of the black holes.

Ghodsi, Ahmad

2010-01-01T23:59:59.000Z

287

Hanford Waste Treatment Plant Sets Massive Protective Shield door in  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Waste Treatment Plant Sets Massive Protective Shield door Waste Treatment Plant Sets Massive Protective Shield door in Pretreatment Facility Hanford Waste Treatment Plant Sets Massive Protective Shield door in Pretreatment Facility January 12, 2011 - 12:00pm Addthis The carbon steel doors come together to form an upside-down L-shape. The 102-ton door was set on top of the 85-ton door that was installed at the end of December. The carbon steel doors come together to form an upside-down L-shape. The 102-ton door was set on top of the 85-ton door that was installed at the end of December. The 102-ton shield door measures 52 feet wide and 15 feet tall The 102-ton shield door measures 52 feet wide and 15 feet tall The carbon steel doors come together to form an upside-down L-shape. The 102-ton door was set on top of the 85-ton door that was installed at the end of December.

288

Topologically Massive Yang-Mills Theory and Link Invariants  

E-Print Network (OSTI)

Topologically massive Yang-Mills theory is studied in the framework of geometric quantization. This theory has a mass gap that is proportional to the topological mass m. Due to the existence of this mass gap, Yang-Mills contribution dies at very large distances compared to 1/m, leaving a pure Chern-Simons theory with level number k. In this paper, an intermediate region is studied where the distance is large enough, so the theory is almost topological, but not infinitely large, so there is still a small contribution from Yang-Mills. It is shown that, this almost topological theory consists of two copies of Chern-Simons, each with level number k/2. As m approaches infinity, they add up to give the original Chern-Simons term with level k. Also, reduction of the phase space is discussed in this limit. Then finally, a relation between the observables of topologically massive Yang-Mills theory and Chern-Simons theory is shown. This allows one to use skein relations to calculate topologically massive Yang-Mills theory observables at large but finite distances.

Tuna Yildirim

2013-11-08T23:59:59.000Z

289

Metadata-Based Parallelization of Program Instrumentation  

E-Print Network (OSTI)

Program instrumentation has a wide variety of useful applications, but tool writers must overcome the challenge of substantial overheads caused by introducing additional code and data into a program. This paper observes that instrumentation usually operates on many discrete, independent data structures, which we call metadata parallelism. We proposes to exploit this phenomenon to reduce the overhead of instrumented programs by executing instrumentation function invocations that manipulate different pieces of metadata simultaneously in different threads. The key challenge to spreading instrumentation function execution across many threads is ensuring that metadata updates occur in the correct order, and do not suffer from data races. Metadata-based parallelization solves this problem by using a user-specified mapping of instrumentation function invocations to serialization sets.

Matthew D. Allen; Gurindar S. Sohi; Matthew D. Allen; Gurindar S. Sohi

2007-01-01T23:59:59.000Z

290

Communication switch for serial and parallel network  

DOE Patents (OSTI)

This is a communication switch apparatus and a method for use in a geographically extensive serial, parallel or hybrid communication network, linking a multiprocessor or parallel processing system. It has a very low software processing overhead and accommodates random burst of high density data. Each processor has a communication switch which may have a data source, data destination, sensor or a robot associated with it. The configuration of the switches are coordinated through a master processor node and depends on the operational phase of the multiprocessor network:data acquisition, data processing and data exchange. The communication system design maximizes data routing while maintaining data integrity which is achieved through the reduction of communication protocol overhead and amplification of signals.

Crosetto, D.B.

1992-01-01T23:59:59.000Z

291

Magnetic field switching in parallel quantum dots  

E-Print Network (OSTI)

We show that the Coulomb blockade in parallel dots pierced by magnetic flux $\\Phi$ completely blocks the resonant current for any value of $\\Phi$ except for integer multiples of the flux quantum $\\Phi_0$. This non-analytic (switching) dependence of the current on $\\Phi$ arises only when the dot states that carry the current are of the same energy. The time needed to reach the steady state, however, diverges when $\\Phi\\to n\\Phi_0$.

Feng Li; Xin-Qi Li; Wei-Min Zhang; S. A. Gurvitz

2008-03-11T23:59:59.000Z

292

Linear conductance through parallel coupled quantum dots  

Science Conference Proceedings (OSTI)

We study the electronic transport through two parallel coupled quantum dots (QDs), employing the X-boson treatment for the single impurity Anderson model. We compute the linear conductance (LC) and transmission coefficient for different regimes of the ... Keywords: 71.10.Ay, 71.27.+a, 73.21.La, 73.23.-b, Fano resonance, Kondo effect, Quantum dot, Transport, X-boson

R. Franco; J. Silva-Valencia; M. S. Figueira

2008-03-01T23:59:59.000Z

293

Performance monitoring of parallel scientific applications  

SciTech Connect

This paper introduces an infrastructure for efficiently collecting performance profiles from parallel HPC codes. Integrated Performance Monitoring (IPM) brings together multiple sources of performance metrics into a single profile that characterizes the overall performance and resource usage of the application. IPM maintains low overhead by using a unique hashing approach which allows a fixed memory footprint and minimal CPU usage. IPM is open source, relies on portable software technologies and is scalable to thousands of tasks.

Skinner, David

2005-05-01T23:59:59.000Z

294

ParCAT: Parallel Climate Analysis Toolkit  

SciTech Connect

Climate science is employing increasingly complex models and simulations to analyze the past and predict the future of Earth s climate. This growth in complexity is creating a widening gap between the data being produced and the ability to analyze the datasets. Parallel computing tools are necessary to analyze, compare, and interpret the simulation data. The Parallel Climate Analysis Toolkit (ParCAT) provides basic tools to efficiently use parallel computing techniques to make analysis of these datasets manageable. The toolkit provides the ability to compute spatio-temporal means, differences between runs or differences between averages of runs, and histograms of the values in a data set. ParCAT is implemented as a command-line utility written in C. This allows for easy integration in other tools and allows for use in scripts. This also makes it possible to run ParCAT on many platforms from laptops to supercomputers. ParCAT outputs NetCDF files so it is compatible with existing utilities such as Panoply and UV-CDAT. This paper describes ParCAT and presents results from some example runs on the Titan system at ORNL.

Smith, Brian E [ORNL; Steed, Chad A [ORNL; Shipman, Galen M [ORNL; Ricciuto, Daniel M [ORNL; Thornton, Peter E [ORNL; Wehner, Michael [Lawrence Berkeley National Laboratory (LBNL); Williams, Dean N. [Lawrence Livermore National Laboratory (LLNL)

2013-01-01T23:59:59.000Z

295

Magnetic Braiding and Parallel Electric Fields  

E-Print Network (OSTI)

The braiding of the solar coronal magnetic field via photospheric motions - with subsequent relaxation and magnetic reconnection -- is one of the most widely debated ideas of solar physics. We readdress the theory in the light of developments in three-dimensional magnetic reconnection theory. It is known that the integrated parallel electric field along field lines is the key quantity determining the rate of reconnection, in contrast with the two-dimensional case where the electric field itself is the important quantity. We demonstrate that this difference becomes crucial for sufficiently complex magnetic field structures. A numerical method is used to relax a braided magnetic field to an ideal force-free equilibrium; that equilibrium is found to be smooth, with only large- scale current structures. However, the equilibrium is shown to have a highly filamentary integrated parallel current structure with extremely short length- scales. An analytical model is developed to show that, in a coronal situation, the length scales associated with the integrated parallel current structures will rapidly decrease with increasing complexity, or degree of braiding, of the magnetic field. Analysis shows the decrease in these length scales will, for any finite resistivity, eventually become inconsistent with the stability of a force- free field. Thus the inevitable consequence of the magnetic braiding process is shown to be a loss of equilibrium of the coronal field, probably via magnetic reconnection events.

A. L. Wilmot-Smith; G. Hornig; D. I. Pontin

2008-10-08T23:59:59.000Z

296

Xyce parallel electronic simulator : reference guide.  

SciTech Connect

This document is a reference guide to the Xyce Parallel Electronic Simulator, and is a companion document to the Xyce Users Guide. The focus of this document is (to the extent possible) exhaustively list device parameters, solver options, parser options, and other usage details of Xyce. This document is not intended to be a tutorial. Users who are new to circuit simulation are better served by the Xyce Users Guide. The Xyce Parallel Electronic Simulator has been written to support, in a rigorous manner, the simulation needs of the Sandia National Laboratories electrical designers. It is targeted specifically to run on large-scale parallel computing platforms but also runs well on a variety of architectures including single processor workstations. It also aims to support a variety of devices and models specific to Sandia needs. This document is intended to complement the Xyce Users Guide. It contains comprehensive, detailed information about a number of topics pertinent to the usage of Xyce. Included in this document is a netlist reference for the input-file commands and elements supported within Xyce; a command line reference, which describes the available command line arguments for Xyce; and quick-references for users of other circuit codes, such as Orcad's PSpice and Sandia's ChileSPICE.

Mei, Ting; Rankin, Eric Lamont; Thornquist, Heidi K.; Santarelli, Keith R.; Fixel, Deborah A.; Coffey, Todd Stirling; Russo, Thomas V.; Schiek, Richard Louis; Warrender, Christina E.; Keiter, Eric Richard; Pawlowski, Roger Patrick

2011-05-01T23:59:59.000Z

297

Parallel Processing with Windows NT Networks  

E-Print Network (OSTI)

Workstation-based parallel processing is an area that is still dominated by Unix-based systems. We have been building new methods for shared-memory parallel processing systems on top of Windows NT based networks of machines. As of present we have been involved in four related systems, called Calypso NT, Chime, Malaxis and MILAN. All of these are middleware, that is they are system level libraries and utility programs that allow programmers to utilize a network efficiently for high volume computations. Calypso was first built on Unix [BDK95], and then ported to Windows NT. Chime and Malaxis are NT systems and MILAN is still under the design phase. This paper describes the systems, the techniques used to implement them on Windows NT and the roadblocks from a Unix programmer's point of view. 1. Introduction This paper describes the experience of porting to and programming with Windows NT (from a Unix programmer 's perspective) while implementing four related parallel processing projec...

Partha Dasgupta

1997-01-01T23:59:59.000Z

298

18.337J / 6.338J Applied Parallel Computing (SMA 5505), Spring 2005  

E-Print Network (OSTI)

Applied Parallel Computing is an advanced interdisciplinary introduction to applied parallel computing on modern supercomputers.

Edelman, Alan

299

On Parallelizing Dual Decomposition in Stochastic Integer Programming |  

NLE Websites -- All DOE Office Websites (Extended Search)

On Parallelizing Dual Decomposition in Stochastic Integer Programming On Parallelizing Dual Decomposition in Stochastic Integer Programming Title On Parallelizing Dual Decomposition in Stochastic Integer Programming Publication Type Journal Article Year of Publication 2013 Authors Lubin, M, Martin, K, Petra, CG, Sandikci, B Journal Operations Research Letters Volume 41 Start Page 252-258 Issue 3 Date Published 05/2013 Other Numbers ANL/MCS-P3037-0912 Abstract For stochastic mixed-integer programs, we revisit the dual decomposition algorithm of Care and Schultz from a computational perspective with the aim of its parallelization. We address an important bottleneck of parallel execution by identifying a formulation that permits the parallel solution of the master program by using structure-exploiting interior-point solvers. Our results demonstrate the potential for parallel speedup and the importance of regularization (stabilization) in the dual optimization. Load imbalance is identified as a remaining barrier to parallel scalability.

300

Constructing parallel corpora for six Indian languages via crowdsourcing  

Science Conference Proceedings (OSTI)

Recent work has established the efficacy of Amazon's Mechanical Turk for constructing parallel corpora for machine translation research. We apply this to building a collection of parallel corpora between English and six languages from the Indian subcontinent: ...

Matt Post; Chris Callison-Burch; Miles Osborne

2012-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "massively parallel microcell-based" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

An Object Oriented Framework for Parallel Multiple Optimizations  

Science Conference Proceedings (OSTI)

This report presents a general Objected-Oriented Framework for Parallel and Multiple Optimizations. We designed a general Objected-Oriented Class Library for Parallel Numerical Optimization. All optimization problems are considered: Unconstrained, Constrained, ...

Beidi Hamma

2000-06-01T23:59:59.000Z

302

The Parallel Scalability of the Spectral Transform Method  

Science Conference Proceedings (OSTI)

This paper investigates the suitability of the spectral transform method for parallel implementation. The spectral transform method is a natural candidate for general circulation models (GCMs) designed to run on large-scale parallel computers due ...

Ian Foster; William Gropp; Rick Stevens

1992-05-01T23:59:59.000Z

303

Design and analysis of data management in scalable parallel scripting  

Science Conference Proceedings (OSTI)

We seek to enable efficient large-scale parallel execution of applications in which a shared filesystem abstraction is used to couple many tasks. Such parallel scripting (many-task computing, MTC) applications suffer poor performance and utilization ...

Zhao Zhang; Daniel S. Katz; Justin M. Wozniak; Allan Espinosa; Ian Foster

2012-11-01T23:59:59.000Z

304

Tracing Static Fields of Embedded Parallel Java Applications  

Science Conference Proceedings (OSTI)

Debugging sequential application code is supported by almost any development environment. But newly upcoming parallel systems rise even harder challenges to application debugging. This is because interrupting or stepping through one of the parallel threads ...

Sascha Uhrig

2011-07-01T23:59:59.000Z

305

Maximum Likelihood Estimation Using Parallel Computing: An Introduction to MPI  

Science Conference Proceedings (OSTI)

The computational difficulty of econometric problems has increased dramatically in recent years as econometricians examine more complicated models and utilize more sophisticated estimation techniques. Many problems in econometrics are `embarrassingly ... Keywords: MPI, maximum likelihood estimation, parallel computing, parallel programming

Christopher A. Swann

2002-04-01T23:59:59.000Z

306

Applications of Parallel Computers Lectures for UCB CS267 Course  

NLE Websites -- All DOE Office Websites (Extended Search)

Computers Applications of Parallel Computers UCB CS267 Spring 2013 Tuesday & Thursday, 9:30-11:00 Pacific Time Applications of Parallel Computers, CS267, is a graduate-level course...

307

Darsim: A Parallel Cycle-Level NoC Simulator  

E-Print Network (OSTI)

We present DARSIM, a parallel, highly configurable, cycle-level network-on-chip simulator based on an ingress-queued wormhole router architecture. The parallel simulation engine offers cycle-accurate as well as periodic ...

Devadas, Srinivas

2010-01-01T23:59:59.000Z

308

Formation of Massive Primordial Stars in a Reionized Gas  

E-Print Network (OSTI)

We use cosmological hydrodynamic simulations with unprecedented resolution to study the formation of primordial stars in an ionized gas at high redshifts. Our approach includes all the relevant atomic and molecular physics to follow the thermal evolution of a prestellar gas cloud to very high densities of ~10^{18} cm^{-3}. We locate a star-forming gas cloud within a reionized region in our cosmological simulation. The first run-away collapse is triggered when the gas cloud's mass is ~40 Msun. We show that the cloud core remains stable against chemo-thermal instability and also against gravitational deformation throughout its evolution. Consequently, a single proto-stellar seed is formed, which accretes the surrounding hot gas at the rate ~10^{-3} Msun/year. We carry out proto-stellar evolution calculations using the inferred accretion rate. The resulting mass of the star when it reaches the zero-age main sequence is M_ZAMS ~40 Msun. We argue that, since the obtained M_ZAMS is as large as the mass of the collapsing parent cloud, the final stellar mass should be close to this value. Such massive, rather than exceptionally massive, primordial stars are expected to cause early chemical enrichment of the Universe by exploding as black hole-forming super/hypernovae, and may also be progenitors of high redshift gamma-ray bursts. The elemental abundance patterns of recently discovered hyper metal-poor stars suggest that they might have been born from the interstellar medium that was metal-enriched by supernovae of these massive primordial stars.

Naoki Yoshida; Kazuyuki Omukai; Lars Hernquist

2007-06-25T23:59:59.000Z

309

Graviton Propagator in a Covariant Massive Gravity Theory  

E-Print Network (OSTI)

We study the massive gravity theory proposed by Arkani-Hamed, Georgi and Schwartz. In this theory, the graviton becomes massive when general covariance is spontaneously broken through the introduction of a field that links two metrics, one of the which will eventually decouple. The excitation of this "link" field acts like a Goldstone boson in giving mass to the graviton. We work out the graviton and Goldstone boson propagators explicitly by means of gauge fixing terms similar to the renormalizability gauges used in gauge theories. With these propagators, we calculate the lowest order tree-level interaction between two external energy momentum tensors. The result is independent of the gauge parameter, but different from the prediction of massless gravity theory, i.e., general relativity. This difference remains even if the mass of the graviton goes to zero, in which case it gives the van Dam-Veltman-Zakharov (vDVZ) discontinuity between the propagators of a massive and massless linearized graviton. Moreover, we show that the Fierz-Pauli graviton mass term can be considered as the ``unitary gauge'' of a more general theory with an extra scalar field. We explicitly construct such a theory in which the vDVZ discontinuity arises with a graviton mass term that is different from the Fierz-Pauli mass term. This theory has a local Weyl symmetry under conformal transformations of the metric. In the case when the mass goes to zero, the Weyl summetry becomes a global symmetry. It is possible that the local Weyl symmetry will give a hint as to the form of the corresponding fully nonlinear theory having a nonzero graviton mass.

Xing Huang; Leonard Parker

2007-05-10T23:59:59.000Z

310

A parallel interior point decomposition algorithm for block angular ...  

E-Print Network (OSTI)

a parallel and distributed high performance computing environment. We compare our. MPI (Message Passing Interface) implementation of the decomposition ...

311

GRB 021004: a Massive Progenitor Star Surrounded by Shells  

E-Print Network (OSTI)

We present spectra of the optical transient of GRB021004 obtained with the Hobby-Eberly telescope starting 15.48, 20.31 hours, and 4.84 days after the burst and a spectrum obtained with the H. J. Smith 2.7 m Telescope starting 14.31 hours after the burst. GRB021004 is the first afterglow whose spectrum is dominated by absorption lines from high ionization species with multiple velocity components separated by up to 3000 km/s. We argue that these lines are likely to come from shells around a massive progenitor star. The high velocities and high ionizations arise from a combination of acceleration and flash-ionization by the burst photons and the wind velocity and steady ionization by the progenitor. We also analyze the broad-band spectrum and the light curve. We distinguish six components along the line of sight: (1) The z~2.293 absorption lines arise from the wind of a massive star. For a mass loss rate of ~6 x 10^{-5} solar masses per year, this component also provides the external medium to create the afterglow light. (2) A second shell produces absorption lines with a relative velocity of 560 km/s, and this is associated with the shell created by the fast massive star wind blowing a bubble in the preceding slow wind at a radial distance of order 10 pc. (3) More distant clouds within the host galaxy lie between 30-2500 pc, where they have been ionized by the burst. (4-6) The massive star wind has clumps with radii and over-densities of 0.022, 0.063, and 0.12 parsecs and 50%, 10%, and 10% respectively. The immediate progenitor of the burster could either be a WC-type Wolf-Rayet star or a highly evolved star whose original mass was just too small for it to become a WN-type Wolf-Rayet star.

Bradley E. Schaefer; C. L. Gerardy; P. Hoflich; A. Panaitescu; R. Quimby; J. Mader; G. J. Hill; P. Kumar; J. C. Wheeler; M. Eracleous; S. Sigurdsson; P. Meszaros; B. Zhang; L. Wang; F. Hessman; V. Petrosian

2002-11-09T23:59:59.000Z

312

Five-dimensional Massive Vector Fields and Radion Stabilization  

E-Print Network (OSTI)

We provide a description of the five-dimensional Higgs mechanism in supersymmetric gauge theories compactified on the orbifold S^1/Z_2 by means of the N=1 superfield formalism. Goldstone bosons absorbed by vector multiplets can come either from hypermultiplets or from gauge multiplets of opposite parity (Hosotani mechanism). Supersymmetry is broken by the Scherk-Schwarz mechanism. In the presence of massive hypermultiplets and gauge multiplets, with different supersymmetric masses, the radion can be stabilized with positive (de Sitter) vacuum energy. The masses of vector and hypermultiplets can be fine-tuned to have zero (Minkowski) vacuum energy.

Emilian Dudas; Mariano Quiros

2005-03-21T23:59:59.000Z

313

Massive Quantum Memories by Periodically Inverted Dynamic Evolutions  

E-Print Network (OSTI)

We introduce a general scheme to realize perfect quantum state reconstruction and storage in systems of interacting qubits. This novel approach is based on the idea of controlling the residual interactions by suitable external controls that, acting on the inter-qubit couplings, yield time-periodic inversions in the dynamical evolution, thus cancelling exactly the effects of quantum state diffusion. We illustrate the method for spin systems on closed rings with XY residual interactions, showing that it enables the massive storage of arbitrarily large numbers of local states, and we demonstrate its robustness against several realistic sources of noise and imperfections.

S. M. Giampaolo; F. Illuminati; A. Di Lisi; G. Mazzarella

2005-06-27T23:59:59.000Z

314

MASSIVE QUANTUM MEMORIES BY PERIODICALLY INVERTED DYNAMIC EVOLUTIONS  

E-Print Network (OSTI)

We introduce a general scheme to realize perfect quantum state reconstruction and storage in systems of interacting qubits. This novel approach is based on the idea of controlling the residual interactions by suitable external controls that, acting on the inter-qubit couplings, yield time-periodic inversions in the dynamical evolution, thus cancelling exactly the effects of quantum state diffusion. We illustrate the method for spin systems on closed rings with XY residual interactions, showing that it enables the massive storage of arbitrarily large numbers of local states, and we demonstrate its robustness against several realistic sources of noise and imperfections. Keywords: Quantum Information; Quantum Control; Spin Systems. 1.

S. M. Giampaolo; F. Illuminati; A. Di Lisi; G. Mazzarella

2005-01-01T23:59:59.000Z

315

Parallelizing AT with MatlabMPI  

SciTech Connect

The Accelerator Toolbox (AT) is a high-level collection of tools and scripts specifically oriented toward solving problems dealing with computational accelerator physics. It is integrated into the MATLAB environment, which provides an accessible, intuitive interface for accelerator physicists, allowing researchers to focus the majority of their efforts on simulations and calculations, rather than programming and debugging difficulties. Efforts toward parallelization of AT have been put in place to upgrade its performance to modern standards of computing. We utilized the packages MatlabMPI and pMatlab, which were developed by MIT Lincoln Laboratory, to set up a message-passing environment that could be called within MATLAB, which set up the necessary pre-requisites for multithread processing capabilities. On local quad-core CPUs, we were able to demonstrate processor efficiencies of roughly 95% and speed increases of nearly 380%. By exploiting the efficacy of modern-day parallel computing, we were able to demonstrate incredibly efficient speed increments per processor in AT's beam-tracking functions. Extrapolating from prediction, we can expect to reduce week-long computation runtimes to less than 15 minutes. This is a huge performance improvement and has enormous implications for the future computing power of the accelerator physics group at SSRL. However, one of the downfalls of parringpass is its current lack of transparency; the pMatlab and MatlabMPI packages must first be well-understood by the user before the system can be configured to run the scripts. In addition, the instantiation of argument parameters requires internal modification of the source code. Thus, parringpass, cannot be directly run from the MATLAB command line, which detracts from its flexibility and user-friendliness. Future work in AT's parallelization will focus on development of external functions and scripts that can be called from within MATLAB and configured on multiple nodes, while expending minimal communication overhead with the integrated MATLAB library.

Li, Evan Y.; /Brown U. /SLAC

2011-06-22T23:59:59.000Z

316

Magnetic field switching in parallel quantum dots  

E-Print Network (OSTI)

We show that the Coulomb blockade in parallel dots pierced by magnetic flux $\\Phi$ completely blocks the resonant current for any value of $\\Phi$ except for integer multiples of the flux quantum $\\Phi_0$. This non-analytic (switching) dependence of the current on $\\Phi$ arises only when the dot states that carry the current are of the same energy. The time needed to reach the steady state, however, diverges when $\\Phi\\to n\\Phi_0$. This current switch effect can find application in nano-circuit devices.

Li, Feng; Zhang, Wei-Min; Gurvitz, S A

2008-01-01T23:59:59.000Z

317

An informal introduction to parallel processors  

Science Conference Proceedings (OSTI)

In the summer of 1992, I had the opportunity to participate in a Faculty Research Program at Argonne National Laboratory. During that time I came in contact with some developments in computer science that were unfamiliar to me as a mathematician. Since most mathematicians have some exposure to computers, but certainly are not computer scientists, I felt it was appropriate to write a paper summarizing my introduction to parallel processing. This paper is not meant to be a full explanation of the topic, but an informal introduction for the ``mathematical layman.``

Hopkins, K.W. [Southwest Baptist Univ., Bolivar, MO (United States)

1994-08-01T23:59:59.000Z

318

Carbothermic reduction with parallel heat sources  

DOE Patents (OSTI)

Disclosed are apparatus and method of carbothermic direct reduction for producing an aluminum alloy from a raw material mix including aluminum oxide, silicon oxide, and carbon wherein parallel heat sources are provided by a combustion heat source and by an electrical heat source at essentially the same position in the reactor, e.g., such as at the same horizontal level in the path of a gravity-fed moving bed in a vertical reactor. The present invention includes providing at least 79% of the heat energy required in the process by the electrical heat source.

Troup, Robert L. (Murrysville, PA); Stevenson, David T. (Washington Township, Washington County, PA)

1984-12-04T23:59:59.000Z

319

Parallel heater system for subsurface formations  

DOE Patents (OSTI)

A heating system for a subsurface formation is disclosed. The system includes a plurality of substantially horizontally oriented or inclined heater sections located in a hydrocarbon containing layer in the formation. At least a portion of two of the heater sections are substantially parallel to each other. The ends of at least two of the heater sections in the layer are electrically coupled to a substantially horizontal, or inclined, electrical conductor oriented substantially perpendicular to the ends of the at least two heater sections.

Harris, Christopher Kelvin (Houston, TX); Karanikas, John Michael (Houston, TX); Nguyen, Scott Vinh (Houston, TX)

2011-10-25T23:59:59.000Z

320

Parallel signal processing for optical satellite detection  

SciTech Connect

An optical satellite detection system can provide a high scan coverage rate if the telescope is scanning the sky continuously, rather than stepping and staring. In the imc signal processor, a high throughput rate has been achieved by dividing the focal plane imaging into five fields-of-view, processing these in a parallel signal processing architecture, and detecting satellites on a several-lines basis rather than waiting for frame-to-frame comparisons. The concepts developed can be applied to a more general detection problem. The signal processing considerations and processor algorithms are discussed. The processor hardware is described, laboratory results are given, and future plans described. 2 references.

Mayer, G.J.; Macdonald, M.J.

1981-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "massively parallel microcell-based" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

The APHID Parallel alpha-beta Search Algorithm  

Science Conference Proceedings (OSTI)

This paper introduces the APHID (Asynchronous Parallel Hierarchical Iterative Deepening) game-tree search algorithm. APHID represents a departure from the approaches used in practice. Instead of parallelism based on the minimal search tree, APHID uses ... Keywords: artificial intelligence, parallel processing, game-tree search, Othello, chess

Mark G. Brockington; Jonathan Schaeffer

1996-10-01T23:59:59.000Z

322

Parallel version of image segmentation algorithm using polygonal markov fields  

Science Conference Proceedings (OSTI)

In this paper we present an application of parallel simulated annealing method to a segmentation algorithm using polygonal Markov fields. After a brief presentation of the algorithm and a general scheme of parallelization methods using simulated annealing ... Keywords: image segmentation, parallel simulated annealing, polygonal Markov field

Rafa? Kluszczy?ski; Piotr Ba?a

2011-09-01T23:59:59.000Z

323

Structure-driven optimizations for amorphous data-parallel programs  

Science Conference Proceedings (OSTI)

Irregular algorithms are organized around pointer-based data structures such as graphs and trees, and they are ubiquitous in applications. Recent work by the Galois project has provided a systematic approach for parallelizing irregular applications based ... Keywords: amorphous data-parallelism, cautious operator implementations, irregular programs, iteration coalescing, one-shot optimization, optimistic parallelization, synchronization overheads

Mario Méndez-Lojo; Donald Nguyen; Dimitrios Prountzos; Xin Sui; M. Amber Hassaan; Milind Kulkarni; Martin Burtscher; Keshav Pingali

2010-01-01T23:59:59.000Z

324

Parallel file system measurement and modeling using colored petri nets  

Science Conference Proceedings (OSTI)

Parallel file systems are significant challenges for high performance data-intensive system designers due to their complexity. Being able to study features and designs before building the actual system is an advantage that a simulation model can offer. ... Keywords: colored petri net, parallel file system modeling, parallel file system simulation, pvfs

Hai Quang Nguyen; Amy Apon

2012-04-01T23:59:59.000Z

325

A Unified Symbolic Evaluation Framework for Parallelizing Compilers  

Science Conference Proceedings (OSTI)

Abstract¿The quality of many optimizations and analyses of parallelizing compilers depends significantly on the ability to evaluate symbolic expressions and on the amount of information available about program variables at arbitrary program points. In ... Keywords: Symbolic analysis, symbolic evaluation, program context, data-flow and control-flow analysis, symbolic dependence testing, compiler optimizations, parallelizing compilers, parallel systems.

Thomas Fahringer; Bernhard Scholz

2000-11-01T23:59:59.000Z

326

Measuring the performance of parallel computers with distributed memory  

Science Conference Proceedings (OSTI)

Basic techniques for measuring the performance of parallel computers with distributed memory are considered. The results obtained via the de-facto standard LINPACK benchmark suite are shown to be weakly related to the efficiency of applied parallel programs. ... Keywords: HPC, MIMD, cluster, communication expenses, data processing, high-performance computing, optimization, parallel computations, performance, supercomputer

R. A. Iushchenko

2009-11-01T23:59:59.000Z

327

Efficient Parallel I/O in Community Atmosphere Model (CAM)  

Science Conference Proceedings (OSTI)

Century-long global climate simulations at high resolutions generate large amounts of data in a parallel architecture. Currently, the community atmosphere model (CAM), the atmospheric component of the NCAR community climate system model (CCSM), uses ... Keywords: CAM, climate modeling, index reshuffle, parallel I/O, parallel netCDF

Yu-Heng Tseng; Chris Ding

2008-05-01T23:59:59.000Z

328

A configurable algorithm for parallel image-compositing applications  

Science Conference Proceedings (OSTI)

Collective communication operations can dominate the cost of large-scale parallel algorithms. Image compositing in parallel scientific visualization is a reduction operation where this is the case. We present a new algorithm called Radix-k that ... Keywords: communication, image compositing, parallel scientific visualization

Tom Peterka; David Goodell; Robert Ross; Han-Wei Shen; Rajeev Thakur

2009-11-01T23:59:59.000Z

329

Parallel computing in Ada: an overview and critique  

Science Conference Proceedings (OSTI)

The aim of this paper is to present the basic issues related to the use of Ada in parallel computing. It is argued that there exists a gap between the most popular area of parallel computing research, scientific computing, and the interests of Ada community. ... Keywords: Ada, efficiency, experimental studies, parallel computing, performance

Marcin Paprzycki; Janusz Zalewski

1997-03-01T23:59:59.000Z

330

Oracle scheduling: controlling granularity in implicitly parallel languages  

Science Conference Proceedings (OSTI)

A classic problem in parallel computing is determining whether to execute a task in parallel or sequentially. If small tasks are executed in parallel, the task-creation overheads can be overwhelming. If large tasks are executed sequentially, processors ... Keywords: granularity control, scheduling, work stealing

Umut A. Acar; Arthur Charguéraud; Mike Rainey

2011-10-01T23:59:59.000Z

331

A scheduling framework for general-purpose parallel languages  

Science Conference Proceedings (OSTI)

The trend in microprocessor design toward multicore and manycore processors means that future performance gains in software will largely come from harnessing parallelism. To realize such gains, we need languages and implementations that can enable parallelism ... Keywords: compilers, heterogeneous parallel languages, run-time systems, scheduling

Matthew Fluet; Mike Rainey; John Reppy

2008-09-01T23:59:59.000Z

332

Parallel volume rendering on the IBM Blue Gene/P  

Science Conference Proceedings (OSTI)

Parallel volume rendering is implemented and tested on an IBM Blue Gene distributed-memory parallel architecture. The goal of studying the cost of parallel rendering on a new class of supercomputers such as the Blue Gene/P is not necessarily to achieve ...

Tom Peterka; Hongfeng Yu; Robert Ross; Kwan-Liu Ma

2008-04-01T23:59:59.000Z

333

Characterizing the Memory Behavior of Compiler-Parallelized Applications  

Science Conference Proceedings (OSTI)

Abstract¿Compiler-parallelized applications are increasing in importance as moderate-scale multiprocessors become common. This paper evaluates how features of advanced memory systems (e.g., longer cache lines) impact memory system behavior for applications ... Keywords: Parallelizing compilers, memory hierarchies, shared-memory multiprocessors, cache performance, false and true sharing, parallelism granularity.

Evan Torrie; Margaret Martonosi; Chau-Wen Tseng; Mary W. Hall

1996-12-01T23:59:59.000Z

334

An efficient parallel solution to the Wigner-Poisson equations  

Science Conference Proceedings (OSTI)

A new model for studying the behavior of nanoscale tunneling devices has been developed in C++ using the Wigner-Poisson formulation. This model incorporates the parallel solvers of Sandia National Lab's Trilinos software with the efficient use of parallel ... Keywords: nanoscale devices, parallel computation, resonant tunneling

A. S. Costolanski, C. T. Kelley, G. W. Howell, A. G. Salinger

2013-04-01T23:59:59.000Z

335

Taming massive distributed datasets: data sampling using bitmap indices  

Science Conference Proceedings (OSTI)

With growing computational capabilities of parallel machines, scientific simulations are being performed at finer spatial and temporal scales, leading to a data explosion. The growing sizes are making it extremely hard to store, manage, disseminate, ... Keywords: big data, bitmap indexing, data sampling

Yu Su; Gagan Agrawal; Jonathan Woodring; Kary Myers; Joanne Wendelberger; James Ahrens

2013-06-01T23:59:59.000Z

336

Parallel detection of temporal events from streaming data  

Science Conference Proceedings (OSTI)

Advanced applications of sensors, network traffic, and financial markets have produced massive, continuous, and time-ordered data streams, calling for high-performance stream querying and event detection techniques. Beyond the widely adopted sequence ...

Hao Wang; Ling Feng; Wenwei Xue

2011-09-01T23:59:59.000Z

337

Switch for serial or parallel communication networks  

DOE Patents (OSTI)

A communication switch apparatus and a method for use in a geographically extensive serial, parallel or hybrid communication network linking a multi-processor or parallel processing system has a very low software processing overhead in order to accommodate random burst of high density data. Associated with each processor is a communication switch. A data source and a data destination, a sensor suite or robot for example, may also be associated with a switch. The configuration of the switches in the network are coordinated through a master processor node and depends on the operational phase of the multi-processor network: data acquisition, data processing, and data exchange. The master processor node passes information on the state to be assumed by each switch to the processor node associated with the switch. The processor node then operates a series of multi-state switches internal to each communication switch. The communication switch does not parse and interpret communication protocol and message routing information. During a data acquisition phase, the communication switch couples sensors producing data to the processor node associated with the switch, to a downlink destination on the communications network, or to both. It also may couple an uplink data source to its processor node. During the data exchange phase, the switch couples its processor node or an uplink data source to a downlink destination (which may include a processor node or a robot), or couples an uplink source to its processor node and its processor node to a downlink destination.

Crosette, Dario B. (DeSoto, TX)

1994-01-01T23:59:59.000Z

338

Parallel machine architecture for production rule systems  

DOE Patents (OSTI)

A parallel processing system for production rule programs utilizes a host processor for storing production rule right hand sides (RHS) and a plurality of rule processors for storing left hand sides (LHS). The rule processors operate in parallel in the recognize phase of the system recognize -Act Cycle to match their respective LHS's against a stored list of working memory elements (WME) in order to find a self consistent set of WME's. The list of WME is dynamically varied during the Act phase of the system in which the host executes or fires rule RHS's for those rules for which a self-consistent set has been found by the rule processors. The host transmits instructions for creating or deleting working memory elements as dictated by the rule firings until the rule processors are unable to find any further self-consistent working memory element sets at which time the production rule system is halted.

Allen, Jr., John D. (Knoxville, TN); Butler, Philip L. (Knoxville, TN)

1989-01-01T23:59:59.000Z

339

Switch for serial or parallel communication networks  

DOE Patents (OSTI)

A communication switch apparatus and a method for use in a geographically extensive serial, parallel or hybrid communication network linking a multi-processor or parallel processing system has a very low software processing overhead in order to accommodate random burst of high density data. Associated with each processor is a communication switch. A data source and a data destination, a sensor suite or robot for example, may also be associated with a switch. The configuration of the switches in the network are coordinated through a master processor node and depends on the operational phase of the multi-processor network: data acquisition, data processing, and data exchange. The master processor node passes information on the state to be assumed by each switch to the processor node associated with the switch. The processor node then operates a series of multi-state switches internal to each communication switch. The communication switch does not parse and interpret communication protocol and message routing information. During a data acquisition phase, the communication switch couples sensors producing data to the processor node associated with the switch, to a downlink destination on the communications network, or to both. It also may couple an uplink data source to its processor node. During the data exchange phase, the switch couples its processor node or an uplink data source to a downlink destination (which may include a processor node or a robot), or couples an uplink source to its processor node and its processor node to a downlink destination. 9 figs.

Crosette, D.B.

1994-07-19T23:59:59.000Z

340

Scientific computations on modern parallel vector systems  

E-Print Network (OSTI)

Computational scientists have seen a frustrating trend of stagnating application performance despite dramatic increases in the claimed peak capability of high performance computing systems. This trend has been widely attributed to the use of superscalar-based commodity components who’s architectural designs offer a balance between memory performance, network capability, and execution rate that is poorly matched to the requirements of large-scale numerical computations. Recently, two innovative parallel-vector architectures have become operational: the Japanese Earth Simulator (ES) and the Cray X1. In order to quantify what these modern vector capabilities entail for the scientists that rely on modeling and simulation, it is critical to evaluate this architectural paradigm in the context of demanding computational algorithms. Our evaluation study examines four diverse scientific applications with the potential to run at ultrascale, from the areas of plasma physics, material science, astrophysics, and magnetic fusion. We compare performance between the vector-based ES and X1, with leading superscalar-based platforms: the IBM Power3/4 and the SGI Altix. Our research team was the first international group to conduct a performance evaluation study at the Earth Simulator Center; remote ES access in not available. Results demonstrate that the vector systems achieve excellent performance on our application suite – the highest of any architecture tested to date. However, vectorization of a particle-incell code highlights the potential difficulty of expressing irregularly structured algorithms as data-parallel programs. 1.

Leonid Oliker; Andrew Canning; Jonathan Carter; John Shalf; Stephane Ethier

2004-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "massively parallel microcell-based" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Observing the Galaxy's massive black hole with gravitational wave bursts  

E-Print Network (OSTI)

An extreme-mass-ratio burst (EMRB) is a gravitational wave signal emitted when a compact object passes through periapsis on a highly eccentric orbit about a much more massive object, in our case a stellar mass object about a 10^6 M_sol black hole. EMRBs are a relatively unexplored means of probing the spacetime of massive black holes (MBHs). We conduct an investigation of the properties of EMRBs and how they could allow us to constrain the parameters, such as spin, of the Galaxy's MBH. We find that if an EMRB event occurs in the Galaxy, it should be detectable for periapse distances r_p < 65 r_g for a \\mu = 10 M_sol orbiting object, where r_g = GM/c^2 is the gravitational radius. The signal-to-noise ratio scales as \\rho ~ -2.7 log(r_p/r_g) + log(\\mu/M_sol) + 4.9. For periapses r_p < 10 r_g, EMRBs can be informative, and provide good constraints on both the MBH's mass and spin. Closer orbits provide better constraints, with the best giving accuracies of better than one part in 10^4 for both the mass and ...

Berry, C P L

2012-01-01T23:59:59.000Z

342

Massive Gravity in de Sitter Space via Gravitational Higgs Mechanism  

E-Print Network (OSTI)

In this paper we discuss massive gravity in de Sitter space via gravitational Higgs mechanism, which provides a nonlinear definition thereof. The Higgs scalars are described by a nonlinear sigma model, which includes higher derivative terms required to obtain the Fierz-Pauli mass term. Using the aforesaid non-perturbative definition, we address appearance of an enhanced local symmetry and a null norm state in the linearized massive gravity in de Sitter space at the special value of the graviton mass to the Hubble parameter ratio. By studying full non-perturbative equations of motion, we argue that there is no enhanced symmetry in the full nonlinear theory. We then argue that in the full nonlinear theory no null norm state is expected to arise at the aforesaid special value. This suggests that no ghost might be present for lower graviton mass values and the full nonlinear theory might be unitary for all values of the graviton mass and the Hubble parameter with no van Dam-Veltman-Zakharov discontinuity. We argue that this is indeed the case by studying full nonlinear Hamiltonian for the relevant conformal and helicity-0 longitudinal modes. In particular, we argue that no negative norm state is present in the full nonlinear theory.

Alberto Iglesias; Zurab Kakushadze

2010-07-14T23:59:59.000Z

343

Modeling of Emission Signatures of Massive Black Hole Binaries: I Methods  

E-Print Network (OSTI)

We model the electromagnetic signatures of massive black hole binaries (MBHBs) with an associated gas component. The method comprises numerical simulations of relativistic binaries and gas coupled with calculations of the physical properties of the emitting gas. We calculate the UV/X-ray and the Halpha light curves and the Halpha emission profiles. The simulations are carried out with a modified version of the parallel tree SPH code Gadget. The heating, cooling, and radiative processes are calculated for two different physical scenarios, where the gas is approximated as a black-body or a solar metallicity gas. The calculation for the solar metallicity scenario is carried out with the photoionization code Cloudy. We focus on sub-parsec binaries which have not yet entered the gravitational radiation phase. The results from the first set of calculations, carried out for a coplanar binary and gas disk, suggest that there are pronounced outbursts in the X-ray light curve during pericentric passages. If such outbursts persist for a large fraction of the lifetime of the system, they can serve as an indicator of this type of binary. The predicted Halpha emission line profiles may be used as a criterion for selection of MBHB candidates from existing archival data. The orbital period and mass ratio of a binary may be inferred after carefully monitoring the evolution of the Halpha profiles of the candidates. The discovery of sub-parsec binaries is an important step in understanding of the merger rates of MBHBs and their evolution towards the detectable gravitational wave window.

Tamara Bogdanovic; Britton D. Smith; Steinn Sigurdsson; Michael Eracleous

2007-08-02T23:59:59.000Z

344

Towards using and improving the NAS parallel benchmarks: a parallel patterns approach  

Science Conference Proceedings (OSTI)

The NAS parallel benchmarks, originally developed by NASA for evaluating performance of their high-performance computers, have been regarded as one of the most widely used benchmark suites for side-by-side comparisons of high-performance machines. However, ...

Vivek Kale

2010-03-01T23:59:59.000Z

345

TotalView Parallel Debugger at NERSC  

NLE Websites -- All DOE Office Websites (Extended Search)

Totalview Totalview Totalview Description TotalView from Rogue Wave Software is a parallel debugging tool that can be run with up to 512 processors. It provides both X Windows-based Graphical User Interface (GUI) and command line interface (CLI) environments for debugging. The performance of the GUI can be greatly improved if used in conjunction with free NX software. The TotalView documentation web page is a good resource for learning more about some of the advanced TotalView features. Accessing Totalview at NERSC To use TotalView at NERSC, first load the TotalView modulefile to set the correct environment settings with the following command: % module load totalview Compiling Code to Run with TotalView In order to use TotalView, code must be compiled with the -g option. We

346

Parallel detecting, spectroscopic ellipsometers/polarimeters  

DOE Patents (OSTI)

The parallel detecting spectroscopic ellipsometer/polarimeter sensor has no moving parts and operates in real-time for in-situ monitoring of the thin film surface properties of a sample within a processing chamber. It includes a multi-spectral source of radiation for producing a collimated beam of radiation directed towards the surface of the sample through a polarizer. The thus polarized collimated beam of radiation impacts and is reflected from the surface of the sample, thereby changing its polarization state due to the intrinsic material properties of the sample. The light reflected from the sample is separated into four separate polarized filtered beams, each having individual spectral intensities. Data about said four individual spectral intensities is collected within the processing chamber, and is transmitted into one or more spectrometers. The data of all four individual spectral intensities is then analyzed using transformation algorithms, in real-time.

Furtak, Thomas E. (15927 W. Ellsworth, Golden, CO 80401)

2002-01-01T23:59:59.000Z

347

SPRNG Parallel Random Number Generators at NERSC  

NLE Websites -- All DOE Office Websites (Extended Search)

SPRNG SPRNG SPRNG Description The SPRNG libraries of generators produce good quality random numbers, and are also fast. They have been subjected to some of the largest random number tests, with around 10^13 RNs per test. SPRNG provides both FORTRAN and C (also C++) interfaces for the use of the parallel random number generators. Access SPRNG v2.0 is available on Carver (gcc, intel and pgi) and Cray systems (pgi and cce). Use the module utility to load the software. module load sprng Using SPRNG On Cray systems: ftn sprng_test.F $SPRNG -lsprng On Carver: mpif90 sprng_test.F $SPRNG -lsprng Documentation On Carver there are various documents in $SPRNG/DOCS and various examples in $SPRNG/EXAMPLES. See the SPRNG web site at Florida State University for complete details. For help using SPRNG at NERSC contact the

348

Internode data communications in a parallel computer  

DOE Patents (OSTI)

Internode data communications in a parallel computer that includes compute nodes that each include main memory and a messaging unit, the messaging unit including computer memory and coupling compute nodes for data communications, in which, for each compute node at compute node boot time: a messaging unit allocates, in the messaging unit's computer memory, a predefined number of message buffers, each message buffer associated with a process to be initialized on the compute node; receives, prior to initialization of a particular process on the compute node, a data communications message intended for the particular process; and stores the data communications message in the message buffer associated with the particular process. Upon initialization of the particular process, the process establishes a messaging buffer in main memory of the compute node and copies the data communications message from the message buffer of the messaging unit into the message buffer of main memory.

Archer, Charles J.; Blocksome, Michael A.; Miller, Douglas R.; Parker, Jeffrey J.; Ratterman, Joseph D.; Smith, Brian E.

2013-09-03T23:59:59.000Z

349

Cosmic Shear from STIS Pure Parallels: Analysis  

E-Print Network (OSTI)

The measurement of cosmic shear requires deep imaging with high image quality on many lines of sight to sample the statistics of large-scale structure. The expected distortion of galaxy images by cosmic shear on the STIS angular scale is a few percent, therefore the PSF anisotropy has to be understood and controlled to an accuracy better than 1%. In this poster we present the analysis of the PSF of STIS and a preliminary cosmic shear measurement using archival data from the STIS pure parallel program to show that the STIS camera on-board HST is well suited for our project. The data reduction and catalog production are described in an accompanying paper (astro-ph/0102330).

H. Haemmerle; J. -M. Miralles; P. Schneider; T. Erben; R. A. E. Fosbury; W. Freudling; N. Pirzkal; S. D. M. White

2001-09-27T23:59:59.000Z

350

Parallel program debugging with flowback analysis  

SciTech Connect

This thesis describes the design and implementation of an integrated debugging system for parallel programs running on shared memory multi-processors. The goal of the debugging system is to present to the programmer a graphical view of the dynamic program dependences while keeping the execution-time overhead low. The author first describes the use of flowback analysis to provide information on causal relationship between events in a programs' execution without re-executing the program for debugging. Execution time overhead is kept low by recording only a small amount of trace during a program's execution. He uses semantic analysis and a technique called incremental tracing to keep the time and space overhead low. As part of the semantic analysis, he uses a static program dependence graph structure that reduces the amount of work done at compile time and takes advantage of the dynamic information produced during execution time. The cornerstone of the incremental tracing concept is to generate a coarse trace during execution and fill incrementally, during the interactive portion of the debugging session, the gap between the information gathered in the coarse trace and the information needed to do the flowback analysis using the coarse trace. Then, he describes how to extend the flowback analysis to parallel programs. The flowback analysis can span process boundaries; i.e., the most recent modification to a shared variable might be traced to a different process than the one that contains the current reference. The static and dynamic program dependence graphs of the individual processes are tied together with synchronization and data dependence information to form complete graphs that represent the entire program.

Choi, Jongdeok.

1989-01-01T23:59:59.000Z

351

Massive hydraulic fracture of Fenton Hill HDR Well EE-3  

DOE Green Energy (OSTI)

Subsequent to a 5.6 million gallon massive hydraulic fracturing (MHF) experiment in Fenton Hill Hot Dry Rock (HDR) Well EE-2, a 2 million gallon MHF was planned for Well EE-3. Although hydraulic communication between wells EE-2 and EE-3 was not established during the initial MHF, a large reservoir was created around EE-2 which seemed to be in proximity with EE-3. The objective of this 2nd MHF was two-fold, to test the reservoir and seismic characteristics of the EE-3 openhole region from 11,390 to 11,770 ft and to drive fractures into the fractured region created earlier by the EE-2 MHF experiment. This paper discusses well repairs to prepare EE-3 for the MHF, the pumping operations, and injection parameters and briefly summarizes seismic results. 2 refs., 6 figs.

Dash, Z.V.; Dreesen, D.S.; Walter, F.; House, L.

1985-01-01T23:59:59.000Z

352

Protecting Recovery Act Cleanup Site During Massive Wildfire  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

July 13, 2011 July 13, 2011 Protecting Recovery Act Cleanup Site During Massive Wildfire LOS ALAMOS, N.M. - Effective safety procedures in place at Los Alamos National Laboratory would have provided protections in the event that the raging Las Conchas fire had spread to the site of an American Recovery and Reinvestment Act project. "Our procedures not only placed the waste excavation site, Materials Disposal Area B (MDA-B), into a safe posture so it was well protected during the fire, but also allowed us to resume work quickly," said Project Director Al Chaloupka. The largest wildfire in New Mexico history forced the Lab to close for more than a week. While firefighters battled the fire, Recovery Act project officials were making plans to re-start the Recovery Act excavation of MDA-B when it was safe to return to

353

Baby Brutes: Simulations Help Solve the Mysteries of Massive Young  

NLE Websites -- All DOE Office Websites (Extended Search)

Baby Brutes Baby Brutes Baby Brutes Simulations Help Solve the Mysteries of Massive Young Star-Forming Galaxies March 31, 2010 | Tags: Astrophysics Contact: Margie Wylie, mwylie@lbl.gov, +1 510 486 7421 Primack-fig1a.png Figure 1. In this model galactic plane (seen in cross section), the energy input of stellar superclusters causes gases to shoot out at speeds up to 1000 kilometers per second at temperatures reaching 100 million Kelvin. These appear as plumes or "chimneys," visible in the top three frames (showing density, temperature, and velocity; the bottom frame shows gas column density). Small bubbles of hot gas in the field (visible in the top two frames) are the result of stellar feedback from runaway stars. Astronomers have in recent years been surprised to find hulking brutes

354

LIMB-DARKENED RADIATION-DRIVEN WINDS FROM MASSIVE STARS  

SciTech Connect

We calculated the influence of the limb-darkened finite-disk correction factor in the theory of radiation-driven winds from massive stars. We solved the one-dimensional m-CAK hydrodynamical equation of rotating radiation-driven winds for all three known solutions, i.e., fast, {Omega}-slow, and {delta}-slow. We found that for the fast solution, the mass-loss rate is increased by a factor of {approx}10%, while the terminal velocity is reduced about 10%, when compared with the solution using a finite-disk correction factor from a uniformly bright star. For the other two slow solutions, the changes are almost negligible. Although we found that the limb darkening has no effects on the wind-momentum-luminosity relationship, it would affect the calculation of synthetic line profiles and the derivation of accurate wind parameters.

Cure, M. [Departamento de Fisica y Astronomia, Facultad de Ciencias, Universidad de Valparaiso, Av. Gran Bretana 1111, Casilla 5030, Valparaiso (Chile); Cidale, L. [Departamento de Espectroscopia, Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata (UNLP), Paseo del Bosque S/N, 1900 La Plata (Argentina); Rial, D. F., E-mail: michel.cure@uv.cl, E-mail: lydia@fcaglp.unlp.edu.ar, E-mail: drial@dm.uba.ar [Departamento de Matematicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (Argentina)

2012-10-01T23:59:59.000Z

355

Search for Charged Massive Long-Lived Particles  

SciTech Connect

We report on a search for charged massive long-lived particles (CMLLPs), based on 5.2 fb{sup -1} of integrated luminosity collected with the D0 detector at the Fermilab Tevatron p{bar p} collider. We search for events in which one or more particles are reconstructed as muons but have speed and ionization energy loss (dE/dx) inconsistent with muons produced in beam collisions. CMLLPs are predicted in several theories of physics beyond the standard model. We exclude pair-produced long-lived gaugino-like charginos below 267 GeV and Higgsino-like charginos below 217 GeV at 95% C.L., as well as long-lived scalar top quarks with mass below 285 GeV.

Abazov V. M.; Abbott B.; Acharya B. S.; Adams M.; Adams T.; Alexeev G. D.; Alimena J.; Alkhazov G.; Alton A.; Alverson G.; Alves G. A.; Aoki M.; Askew A.; Asman B.; Atkins S.; Atramentov O.; Augsten K.; Avila C.; BackusMayes J.; Badaud F.; Bagby L.; Baldin B.; Bandurin D. V.; Banerjee S.; Barberis E.; Baringer P.; Barreto J.; Bartlett J. F.; Bassler U.; Bazterra V.; Bean A.; Begalli M.; Belanger-Champagne C.; Bellantoni L.; Beri S. B.; Bernardi G.; Bernhard R.; Bertram I.; Besancon M.; Beuselinck R.; Bezzubov V. A.; Bhat P. C.; Bhatnagar V.; Blazey G.; Blessing S.; Bloom K.; Boehnlein A.; Boline D.; Boos E. E.; Borissov G.; Bose T.; Brandt A.; Brandt O.; Brock R.; Brooijmans G.; Bross A.; Brown D.; Brown J.; Bu X. B.; Buehler M.; Buescher V.; Bunichev V.; Burdin S.; Burnett T. H.; Buszello C. P.; Calpas B.; Camacho-Perez E.; Carrasco-Lizarraga M. A.; Casey B. C. K.; Castilla-Valdez H.; Chakrabarti S.; Chakraborty D.; Chan K. M.; Chandra A.; Chapon E.; Chen G.; Chevalier-Thery S.; Cho D. K.; Cho S. W.; Choi S.; Choudhary B.; Cihangir S.; Claes D.; Clutter J.; Cooke M.; Cooper W. E.; Corcoran M.; Couderc F.; Cousinou M. -C.; Croc A.; Cutts D.; Das A.; Davies G.; De K.; de Jong S. J.; De la Cruz-Burelo E.; Deliot F.; Demina R.; Denisov D.; Denisov S. P.; Desai S.; Deterre C.; DeVaughan K.; Diehl H. T.; Diesburg M.; Ding P. F.; Dominguez A.; Dorland T.; Dubey A.; Dudko L. V.; Duggan D.; Duperrin A.; Dutt S.; Dyshkant A.; Eads M.; Edmunds D.; Ellison J.; Elvira V. D.; Enari Y.; Evans H.; Evdokimov A.; Evdokimov V. N.; Facini G.; Ferbel T.; Fiedler F.; Filthaut F.; Fisher W.; Fisk H. E.; Fortner M.; Fox H.; Fuess S.; Garcia-Bellido A.; Garcia-Guerra G. A.; Gavrilov V.; Gay P.; Geng W.; Gerbaudo D.; Gerber C. E.; Gershtein Y.; Ginther G.; Golovanov G.; Goussiou A.; Grannis P. D.; Greder S.; Greenlee H.; Greenwood Z. D.; Gregores E. M.; Grenier G.; Gris Ph.; Grivaz J. -F.; Grohsjean A.; Gruenendahl S.; Gruenewald M. W.; Guillemin T.; Gutierrez G.; Gutierrez P.; Haas A.; Hagopian S.; Haley J.; Han L.; Harder K.; Harel A.; Hauptman J. M.; Hays J.; Head T.; Hebbeker T.; Hedin D.; Hegab H.; Heinson A. P.; Heintz U.; Hensel C.; Heredia-De La Cruz I.; Herner K.; Hesketh G.; Hildreth M. D.; Hirosky R.; Hoang T.; Hobbs J. D.; Hoeneisen B.; Hohlfeld M.; Hubacek Z.; Hynek V.; Iashvili I.; Ilchenko Y.; Illingworth R.; Ito A. S.; Jabeen S.; Jaffre M.; Jamin D.; Jayasinghe A.; Jesik R.; Johns K.; Johnson M.; Jonckheere A.; Jonsson P.; Joshi J.; Jung A. W.; Juste A.; Kaadze K.; Kajfasz E.; Karmanov D.; Kasper P. A.; Katsanos I.; Kehoe R.; Kermiche S.; Khalatyan N.; Khanov A.; Kharchilava A.; Kharzheev Y. N.; Kohli J. M.; Kozelov A. V.; Kraus J.; Kulikov S.; Kumar A.; Kupco A.; Kurca T.; Kuzmin V. A.; Kvita J.; Lammers S.; Landsberg G.; Lebrun P.; Lee H. S.; Lee S. W.; Lee W. M.; Lellouch J.; Li L.; Li Q. Z.; Lietti S. M.; Lim J. K.; Lincoln D.; Linnemann J.; Lipaev V. V.; Lipton R.; Liu Y.; Lobodenko A.; Lokajicek M.; de Sa R. Lopes; Lubatti H. J.; Luna-Garcia R.; Lyon A. L.; Maciel A. K. A.; Mackin D.; Madar R.; Magana-Villalba R.; Malik S.; Malyshev V. L.; Maravin Y.; Martinez-Ortega J.; McCarthy R.; McGivern C. L.; Meijer M. M.; et al.

2012-03-21T23:59:59.000Z

356

A Massive Pulsar in a Compact Relativistic Binary  

E-Print Network (OSTI)

Many physically motivated extensions to general relativity (GR) predict significant deviations in the properties of spacetime surrounding massive neutron stars. We report the measurement of a 2.01 +/- 0.04 solar mass pulsar in a 2.46-hr orbit with a 0.172 +/- 0.003 solar mass white dwarf. The high pulsar mass and the compact orbit make this system a sensitive laboratory of a previously untested strong-field gravity regime. Thus far, the observed orbital decay agrees with GR, supporting its validity even for the extreme conditions present in the system. The resulting constraints on deviations support the use of GR-based templates for ground-based gravitational wave detectors. Additionally, the system strengthens recent constraints on the properties of dense matter and provides insight to binary stellar astrophysics and pulsar recycling.

John Antoniadis; Paulo C. C. Freire; Norbert Wex; Thomas M. Tauris; Ryan S. Lynch; Marten H. van Kerkwijk; Michael Kramer; Cees Bassa; Vik S. Dhillon; Thomas Driebe; Jason W. T. Hessels; Victoria M. Kaspi; Vladislav I. Kondratiev; Norbert Langer; Thomas R. Marsh; Maura A. McLaughlin; Timothy T. Pennucci; Scott M. Ransom; Ingrid H. Stairs; Joeri van Leeuwen; Joris P. W. Verbiest; David G. Whelan

2013-04-25T23:59:59.000Z

357

PHYSICS PROCESSES IN DISRUPTION MITIGATION USING MASSIVE NOBLE GAS INJECTION  

SciTech Connect

Methods for detecting imminent disruptions and mitigating disruption effects using massive injection of noble gases (He, Ne, or Ar) have been demonstrated on the DIII-D tokamak [1]. A jet of high injected gas density (> 10{sup 24} m{sup -3}) and pressure (> 20 kPa) penetrates the target plasma at the gas sound speed ({approx}300-500 m/s) and increases the atom/ion content of the plasma by a factor of > 50 in several milliseconds. UV line radiation from the impurity species distributes the plasma energy uniformly on the first wall, reducing the thermal load to the divertor by a factor of 10. Runaway electrons are almost completely eliminated by the large density of free and bound electrons supplied by the gas injection. The small vertical plasma displacement before current quench and high ratio of current decay rate to vertical growth rate result in a 75% reduction in peak halo current amplitude and attendant forces.

D.A. HUMPHREYS; D.G. WHYTE; T.C. JERNIGAN; T.E.EVANS; D.S. GRAY; E.M. HOLLMANN; A.W. HYATT; A.G. KELLMAN; C.J. LASNIER; P.B. PARKS; P.L. TAYLOR

2002-07-01T23:59:59.000Z

358

The Higgs scalar field with no massive Higgs particle  

E-Print Network (OSTI)

The postulate that all massless elementary fields have conformal Weyl local scaling symmetry has remarkable consequences for both cosmology and elementary particle physics. Conformal symmetry couples scalar and gravitational fields. Implications for the scalar field of a conformal Higgs model are considered here. The energy-momentum tensor of a conformal Higgs scalar field determines a cosmological constant. It has recently been shown that this accounts for the observed magnitude of dark energy. The gravitational field equation forces the energy density to be finite, which precludes spontaneous destabilization of the vacuum state. Scalar field fluctuations would define a Higgs tachyon rather than a massive particle, consistent with the ongoing failure to observe such a particle.

R. K. Nesbet

2010-08-19T23:59:59.000Z

359

A Search for Charged Massive Stable Particles at D0  

SciTech Connect

A search for charged massive stable particles has been performed with the D0 detector at the Fermilab Tevatron. The signature is two particles reconstructed as muons, but with speed and invariant mass inconsistent with beam-produced muons. No excess of events is observed and limits are set on the production cross-section for pair-produced stable stau sleptons based on 390 pb{sup -1} of data. Limits vary from 0.06 pb to 0.62 pb, depending on the stau mass, and are the strictest Tevatron limits to date. Mass limits are also set for stable charginos. The limits are 140 GeV/c{sup 2} for a higgsino-like chargino and 174 GeV/c{sup 2} for a gaugino-like chargino. These are currently the best limits to date for stable charginos.

Eads, Michael T.; /Northern Illinois U.

2005-08-01T23:59:59.000Z

360

Massive Social Network Analysis: Mining Twitter for Social Good  

Science Conference Proceedings (OSTI)

Social networks produce an enormous quantity of data. Facebook consists of over 400 million active users sharing over 5 billion pieces of information each month. Analyzing this vast quantity of unstructured data presents challenges for software and hardware. We present GraphCT, a Graph Characterization Tooklit for massive graphs representing social network data. On a 128-processor Cray XMT, GraphCT estimates the betweenness centrality of an artificially generated (R-MAT) 537 million vertex, 8.6 billion edge graph in 55 minutes. We use GraphCT to analyze public data from Twitter, a microblogging network. Twitter's message connections appear primarily tree-structured as a news dissemination system. Within the public data, however, are clusters of conversations. Using GraphCT, we can rank actors within these conversations and help analysts focus attention on a much smaller data subset.

Ediger, David; Jiang, Karl; Riedy, Edward J.; Bader, David A.; Corley, Courtney D.; Farber, Robert M.; Reynolds, William

2010-10-11T23:59:59.000Z

Note: This page contains sample records for the topic "massively parallel microcell-based" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Gravitational Quenching in Massive Galaxies and Clusters by Clumpy Accretion  

E-Print Network (OSTI)

We consider a simple gravitational-heating mechanism for the long-term quenching of cooling flows and star formation in massive dark-matter haloes hosting ellipticals and clusters. The virial shock heating in haloes >10^12 Mo triggers quenching in 10^12-13 Mo haloes (Birnboim, Dekel & Neistein 2007). We show that the long-term quenching in haloes >Mmin~7x10^12 Mo could be due to the gravitational energy of cosmological accretion delivered to the inner-halo hot gas by cold flows via ram-pressure drag and local shocks. Mmin is obtained by comparing the gravitational power of infall into the potential well with the overall radiative cooling rate. The heating wins if the gas inner density cusp is not steeper than r^-0.5 and if the masses in the cold and hot phases are comparable. The effect is stronger at higher redshifts, making the maintenance easier also at later times. Clumps >10^5 Mo penetrate to the inner halo with sufficient kinetic energy before they disintegrate, but they have to be Alternatively, such clumps may be embedded in dark-matter subhaloes if the ionizing flux is ineffective, but they separate from their subhaloes by ram pressure before entering the inner halo. Heating by dynamical friction becomes dominant for massive satellites, which can contribute up to one third of the total gravitational heating. We conclude that gravitational heating by cosmological accretion is a viable alternative to AGN feedback as a long-term quenching mechanism.

Avishai Dekel; Yuval Birnboim

2007-07-09T23:59:59.000Z

362

Data communications in a parallel active messaging interface of a parallel computer  

DOE Patents (OSTI)

Algorithm selection for data communications in a parallel active messaging interface (`PAMI`) of a parallel computer, the PAMI composed of data communications endpoints, each endpoint including specifications of a client, a context, and a task, endpoints coupled for data communications through the PAMI, including associating in the PAMI data communications algorithms and ranges of message sizes so that each algorithm is associated with a separate range of message sizes; receiving in an origin endpoint of the PAMI a data communications instruction, the instruction specifying transmission of a data communications message from the origin endpoint to a target endpoint, the data communications message characterized by a message size; selecting, from among the associated algorithms and ranges, a data communications algorithm in dependence upon the message size; and transmitting, according to the selected data communications algorithm from the origin endpoint to the target endpoint, the data communications message.

Davis, Kristan D; Faraj, Daniel A

2013-07-09T23:59:59.000Z

363

Data communications for a collective operation in a parallel active messaging interface of a parallel computer  

DOE Patents (OSTI)

Algorithm selection for data communications in a parallel active messaging interface (`PAMI`) of a parallel computer, the PAMI composed of data communications endpoints, each endpoint including specifications of a client, a context, and a task, endpoints coupled for data communications through the PAMI, including associating in the PAMI data communications algorithms and bit masks; receiving in an origin endpoint of the PAMI a collective instruction, the instruction specifying transmission of a data communications message from the origin endpoint to a target endpoint; constructing a bit mask for the received collective instruction; selecting, from among the associated algorithms and bit masks, a data communications algorithm in dependence upon the constructed bit mask; and executing the collective instruction, transmitting, according to the selected data communications algorithm from the origin endpoint to the target endpoint, the data communications message.

Faraj, Daniel A

2013-07-16T23:59:59.000Z

364

Online gaming: a scoping study of massively multi-player online role playing games  

Science Conference Proceedings (OSTI)

The popularity of Massively Multiplayer Online Role-Playing Games (MMORPGs) has risen greatly over the last few years. To date there has been very little published academic research concerning online gaming and even less on the different types of online ... Keywords: Massively multiplayer online games, Scoping study

Alex Meredith; Zaheer Hussain; Mark D. Griffiths

2009-06-01T23:59:59.000Z

365

Deploying a massively multiplayer online game with a low-latency server infrastructure  

Science Conference Proceedings (OSTI)

The massively multiplayer online game (MMOG) industry has become an important e-commerce segment due to its impact on the economy. A MMOG requires the deployment of dozens to hundreds of n-tiered servers around the world to support millions of concurrent ... Keywords: Facility, Location, Massively multiplayer online games, Model

Yi Sun; Jack Y. Leu

2011-03-01T23:59:59.000Z

366

MC++: Parallel, portable, Monte Carlo neutron transport in C++  

Science Conference Proceedings (OSTI)

We have developed an implicit Monte Carlo neutron transport code in C++ using the Parallel Object-Oriented Methods and Applications (POOMA) class library. MC++ runs in parallel on and is portable to a wide variety of platforms, including MPPs, clustered SMPs, and individual workstations. It contains appropriate classes and abstractions for particle transport and parallelism. Current capabilities of MC++ are discussed, along with future plans and physics and performance results on many different platforms.

Lee, S.R.; Cummings, J.C. [Los Alamos National Lab., NM (United States); Nolen, S.D. [Texas A& M Univ., College Station, TX (United States). Dept. of Nuclear Engineering

1997-02-01T23:59:59.000Z

367

FORMATION OF MASSIVE MOLECULAR CLOUD CORES BY CLOUD-CLOUD COLLISION  

SciTech Connect

Recent observations of molecular clouds around rich massive star clusters including NGC 3603, Westerlund 2, and M20 revealed that the formation of massive stars could be triggered by a cloud-cloud collision. By using three-dimensional, isothermal, magnetohydrodynamics simulations with the effect of self-gravity, we demonstrate that massive, gravitationally unstable, molecular cloud cores are formed behind the strong shock waves induced by cloud-cloud collision. We find that the massive molecular cloud cores have large effective Jeans mass owing to the enhancement of the magnetic field strength by shock compression and turbulence in the compressed layer. Our results predict that massive molecular cloud cores formed by the cloud-cloud collision are filamentary and threaded by magnetic fields perpendicular to the filament.

Inoue, Tsuyoshi [Department of Physics and Mathematics, Aoyama Gakuin University, Sagamihara, Kanagawa 252-5258 (Japan); Fukui, Yasuo, E-mail: inouety@phys.aoyama.ac.jp [Department of Physics, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602 (Japan)

2013-09-10T23:59:59.000Z

368

Generalized Pattern Search in a Parallel Environment - CECM  

E-Print Network (OSTI)

Nov 2, 2002 ... 1. Generalized Pattern Search in a Parallel. Environment. Mason Macklem. Mathematics and Statistics. Simon Fraser University. November 2 ...

369

Parallel Coordinate Descent Methods for Big Data Optimization ?  

E-Print Network (OSTI)

Dec 4, 2012 ... This often drastically reduces memory requirements as well as the ... does parallelization of a coordinate descent method lead to acceleration?

370

A parallel between two classes of pricing problems in transportation ...  

E-Print Network (OSTI)

Jan 5, 2009 ... A parallel between two classes of pricing problems in transportation and economics. Géraldine Heilporn (Geraldine.Heilporn ***at*** hec.ca)

371

Large Scale Parallel Lattice Boltzmann Model of Dendritic Growth  

Science Conference Proceedings (OSTI)

Abstract Scope, We present a parallel lattice Boltzmann - cellular automaton model for the simulation of two-dimensional dendritic growth during solidification of ...

372

Improving Between-Shot Fusion Data Analysis with Parallel Structures  

SciTech Connect

In the Phase I project we concentrated on three technical objectives to demonstrate the feasibility of the Phase II project: (1) the development of a parallel MDSplus data handler, (2) the parallelization of existing fusion data analysis packages, and (3) the development of techniques to automatically generate parallelized code using pre-compiler directives. We summarize the results of the Phase I research for each of these objectives below. We also describe below additional accomplishments related to the development of the TaskDL and mpiDL parallelization packages.

CHET NIETER

2005-07-27T23:59:59.000Z

373

Parallel Sparse Polynomial Division Using Heaps - CECM - Simon ...  

E-Print Network (OSTI)

reduce contention by up to an order of magnitude. We first used the trick of caching shared variables in the circular buffers of the parallel multiplication algorithm ...

374

Bayesian parallel Imaging with edge-preserving priors  

E-Print Network (OSTI)

Gibbs distributions, and the Bayesian restoration of images.NIH-PA Author Manuscript Bayesian Parallel Imaging WithSociety; MRIs for MRFs: Bayesian reconstruction of MR images

2007-01-01T23:59:59.000Z

375

Hybrid MPI/OpenMP parallel support vector machine training  

E-Print Network (OSTI)

Jan 12, 2009 ... A parallel implementation of Support Vector Machine training has been developed, using a combination of MPI and OpenMP. Using an interior ...

376

A multiprocessor architecture combining fine-grained and coarse-grained parallelism strategies  

Science Conference Proceedings (OSTI)

Keywords: coarse-grained, fine-grained, instruction-level parallelism, loop-level parallelism, multiprocessor, performance comparisons, pipelining, superscalar

David J. Lilja

1994-05-01T23:59:59.000Z

377

Gyrokinetic Toroidal Code: a 3D Parallel Particle-in-Cell Code to Study Microturbulence in Magnetized Plasmas  

NLE Websites -- All DOE Office Websites (Extended Search)

benchmarking and benchmarking and optimizing GTC on High Performance Computers Stéphane Ethier Princeton Plasma Physics Laboratory NERSC Users' Group meeting June 2006 Work Supported by DOE Contract No.DE-AC02-76CH03073 and by the DOE SciDAC Center for Gyrokinetic Particle Simulation of Turbulent Transport in Burning Plasmas. The Gyrokinetic Toroidal Code * 3D particle-in-cell code to study microturbulence in magnetically confined fusion plasmas. * Solves the gyro-averaged Vlasov equation. * Gyrokinetic Poisson equation solved in real space. * Low noise δf method. * Global code (full torus as opposed to only a flux tube). * Massively parallel: typical runs done on 1024 processors. * Electrostatic approximation with adiabatic electrons. * Nonlinear and fully self-consistent. * Written in Fortran 90/95

378

I; FAST PARALLEL PIPELINED READOUT ARCHITECTURE FOR A COMPLETELY FLASH DIGITIZING SYSTEM WITH MULTI-LEVEL TRIGGER  

E-Print Network (OSTI)

We have built, and used to take physics data, a digitizing and readout system for Brookhaven AGS Experiment 791, a high-rate search for rare kaon decays. All digitization- of charge and time information is “flash ” (performed in less than 200 ns), followed by front-end buffering and a pipelined readout with massive parallelism. A data transfer rate of-- 0.5- Gigabytelsec into dual-port memories in eight 3081-emulating processors has been achieved. A readout-supervising circuit coordinates the three levels of event triggering and the movement of data throughout the system. The host Micro-VAX is interrupted only for the uploading of packets of fully filtered events from the 3081/E’s, Digitizing and data transfer from the front end to the 3081/E’s contribute negligible deadtime to the experiment.

_ Robert D. Cousins; Jacob Konigsberg; Jonathan Kubic; Philip L. Mel; Gregory W. Hart; W& n R. Molzonq; George M. Irwin; Dale A. Ouimette B; Jack L. Ritchiec; Quang H. Trang; Robert J. Whyleyd

1988-01-01T23:59:59.000Z

379

Current parallel I/O limitations to scalable data analysis.  

Science Conference Proceedings (OSTI)

This report describes the limitations to parallel scalability which we have encountered when applying our otherwise optimally scalable parallel statistical analysis tool kit to large data sets distributed across the parallel file system of the current premier DOE computational facility. This report describes our study to evaluate the effect of parallel I/O on the overall scalability of a parallel data analysis pipeline using our scalable parallel statistics tool kit [PTBM11]. In this goal, we tested it using the Jaguar-pf DOE/ORNL peta-scale platform on a large combustion simulation data under a variety of process counts and domain decompositions scenarios. In this report we have recalled the foundations of the parallel statistical analysis tool kit which we have designed and implemented, with the specific double intent of reproducing typical data analysis workflows, and achieving optimal design for scalable parallel implementations. We have briefly reviewed those earlier results and publications which allow us to conclude that we have achieved both goals. However, in this report we have further established that, when used in conjuction with a state-of-the-art parallel I/O system, as can be found on the premier DOE peta-scale platform, the scaling properties of the overall analysis pipeline comprising parallel data access routines degrade rapidly. This finding is problematic and must be addressed if peta-scale data analysis is to be made scalable, or even possible. In order to attempt to address these parallel I/O limitations, we will investigate the use the Adaptable IO System (ADIOS) [LZL+10] to improve I/O performance, while maintaining flexibility for a variety of IO options, such MPI IO, POSIX IO. This system is developed at ORNL and other collaborating institutions, and is being tested extensively on Jaguar-pf. Simulation code being developed on these systems will also use ADIOS to output the data thereby making it easier for other systems, such as ours, to process that data.

Mascarenhas, Ajith Arthur; Pebay, Philippe Pierre

2011-07-01T23:59:59.000Z

380

WAS THE SUN BORN IN A MASSIVE CLUSTER?  

Science Conference Proceedings (OSTI)

A number of authors have argued that the Sun must have been born in a cluster of no more than several thousand stars, on the basis that, in a larger cluster, close encounters between the Sun and other stars would have truncated the outer solar system or excited the outer planets into eccentric orbits. However, this dynamical limit is in tension with meteoritic evidence that the solar system was exposed to a nearby supernova during or shortly after its formation; a several-thousand-star cluster is much too small to produce a massive star whose lifetime is short enough to have provided the enrichment. In this paper, we revisit the dynamical limit in the light of improved observations of the properties of young clusters. We use a series of scattering simulations to measure the velocity-dependent cross-section for disruption of the outer solar system by stellar encounters, and use this cross-section to compute the probability of a disruptive encounter as a function of birth cluster properties. We find that, contrary to prior work, the probability of disruption is small regardless of the cluster mass, and that it actually decreases rather than increases with cluster mass. Our results differ from prior work for three main reasons: (1) unlike in most previous work, we compute a velocity-dependent cross-section and properly integrate over the cluster mass-dependent velocity distribution of incoming stars; (2) we recognize that {approx}90% of clusters have lifetimes of a few crossing times, rather than the 10-100 Myr adopted in many earlier models; and (3) following recent observations, we adopt a mass-independent surface density for embedded clusters, rather than a mass-independent radius as assumed many earlier papers. Our results remove the tension between the dynamical limit and the meteoritic evidence, and suggest that the Sun was born in a massive cluster. A corollary to this result is that close encounters in the Sun's birth cluster are highly unlikely to truncate the Kuiper Belt unless the Sun was born in one of the unusual clusters that survived for tens of Myr. However, we find that encounters could plausibly produce highly eccentric Kuiper Belt objects such as Sedna.

Dukes, Donald; Krumholz, Mark R. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)

2012-07-20T23:59:59.000Z

Note: This page contains sample records for the topic "massively parallel microcell-based" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Parallel visualization and analysis with paraview on a Cray XT4  

SciTech Connect

Scientific data sets produced by modern supercomputers like ORNL's Cray XT 4, Jaguar, can be extremely large, making visualization and analysis more difficult as moving large resultant data to dedicated analysis systems can be prohibitively expensive. We share our continuing work of integrating a parallel visualization system, ParaView, on ORNL's Jaguar system and our efforts to enable extreme scale interactive data visualization and analysis. We will discuss porting challenges and present performance numbers. Jaguar is a Cray XT4 with 7,832 compute nodes each with 4 cores and 8GB of memory, located in Oak Ridge, Tennessee. Jaguar is currently ranked No.8 in the Top 500. Jaguar, and other machines like it, enable increasingly larger data sets. Whether scientists are producing extremely massive data or small data they still have a requirement for analysis. Analysis is often difficult for larger data and it is further complicated when the user is distant to the data. Data sets that are too large to ship and/or analyze on a single desktop require a parallel analysis tool and a high performance computer to run on. Running ParaView interactively on Jaguar is a positive improvement for both local and remote users. We have shown that it is feasible for our user at LANL to visualize his simulation data created on jaguar. Local users may face fewer obstacles and get improved performance, due to their higher bandwidth to Jaguar. For future work, we would like to see higher priority queues that enable interactive visualization. A more interactive user-friendly qsub that estimates time to allocation would be very useful. Hopefully, our work will lead to more users attempting interactive visualization on Jaguar, resulting in quicker turnaround times for visualization and analysis. As users migrate to using supercomputing platforms for visualization, we expect future research possibilities in this area.

Ahrens, James P [Los Alamos National Laboratory; Patchett, John M [Los Alamos National Laboratory; Pugmire, David L [ORNL; Ahern, Sean [ORNL

2010-01-01T23:59:59.000Z

382

Parallel Computing for Terrestrial Ecosystem Carbon Modeling  

Science Conference Proceedings (OSTI)

Terrestrial ecosystems are a primary component of research on global environmental change. Observational and modeling research on terrestrial ecosystems at the global scale, however, has lagged behind their counterparts for oceanic and atmospheric systems, largely because the unique challenges associated with the tremendous diversity and complexity of terrestrial ecosystems. There are 8 major types of terrestrial ecosystem: tropical rain forest, savannas, deserts, temperate grassland, deciduous forest, coniferous forest, tundra, and chaparral. The carbon cycle is an important mechanism in the coupling of terrestrial ecosystems with climate through biological fluxes of CO{sub 2}. The influence of terrestrial ecosystems on atmospheric CO{sub 2} can be modeled via several means at different timescales. Important processes include plant dynamics, change in land use, as well as ecosystem biogeography. Over the past several decades, many terrestrial ecosystem models (see the 'Model developments' section) have been developed to understand the interactions between terrestrial carbon storage and CO{sub 2} concentration in the atmosphere, as well as the consequences of these interactions. Early TECMs generally adapted simple box-flow exchange models, in which photosynthetic CO{sub 2} uptake and respiratory CO{sub 2} release are simulated in an empirical manner with a small number of vegetation and soil carbon pools. Demands on kinds and amount of information required from global TECMs have grown. Recently, along with the rapid development of parallel computing, spatially explicit TECMs with detailed process based representations of carbon dynamics become attractive, because those models can readily incorporate a variety of additional ecosystem processes (such as dispersal, establishment, growth, mortality etc.) and environmental factors (such as landscape position, pest populations, disturbances, resource manipulations, etc.), and provide information to frame policy options for climate change impact analysis.

Wang, Dali [ORNL; Post, Wilfred M [ORNL; Ricciuto, Daniel M [ORNL; Berry, Michael [University of Tennessee, Knoxville (UTK)

2011-01-01T23:59:59.000Z

383

Petascale Parallelization of the Gyrokinetic Toroidal Code  

SciTech Connect

The Gyrokinetic Toroidal Code (GTC) is a global, three-dimensional particle-in-cell application developed to study microturbulence in tokamak fusion devices. The global capability of GTC is unique, allowing researchers to systematically analyze important dynamics such as turbulence spreading. In this work we examine a new radial domain decomposition approach to allow scalability onto the latest generation of petascale systems. Extensive performance evaluation is conducted on three high performance computing systems: the IBM BG/P, the Cray XT4, and an Intel Xeon Cluster. Overall results show that the radial decomposition approach dramatically increases scalability, while reducing the memory footprint - allowing for fusion device simulations at an unprecedented scale. After a decade where high-end computing (HEC) was dominated by the rapid pace of improvements to processor frequencies, the performance of next-generation supercomputers is increasingly differentiated by varying interconnect designs and levels of integration. Understanding the tradeoffs of these system designs is a key step towards making effective petascale computing a reality. In this work, we examine a new parallelization scheme for the Gyrokinetic Toroidal Code (GTC) [?] micro-turbulence fusion application. Extensive scalability results and analysis are presented on three HEC systems: the IBM BlueGene/P (BG/P) at Argonne National Laboratory, the Cray XT4 at Lawrence Berkeley National Laboratory, and an Intel Xeon cluster at Lawrence Livermore National Laboratory. Overall results indicate that the new radial decomposition approach successfully attains unprecedented scalability to 131,072 BG/P cores by overcoming the memory limitations of the previous approach. The new version is well suited to utilize emerging petascale resources to access new regimes of physical phenomena.

Ethier, Stephane; Adams, Mark; Carter, Jonathan; Oliker, Leonid

2010-05-01T23:59:59.000Z

384

The Next-Generation Massively Parallel Reactive Flow and Transport Code PFLOTRAN: Application to CO2 Storage in Saline Aquifers P. Lichtner  

E-Print Network (OSTI)

-oriented style in Fortran 90 and uses modern constructs such as derived types, pointers, and linked lists. Recently, PFLOTRAN has been run on a one billion node real-world problem (Hanford 300 Area) as proof

Mills, Richard

385

Efficient parallel processing with spin-wave nanoarchitectures  

Science Conference Proceedings (OSTI)

In this paper, we study the algorithm design aspects of three newly developed spin-wave architectures. The architectures are capable of simultaneously transmitting multiple signals using different frequencies, and allow for concurrent read/write operations. ... Keywords: Nanoscale spin-wave architectures, Parallel algorithms, Parallel architectures, Routing

Mary M. Eshaghian-Wilner; Shiva Navab

2009-08-01T23:59:59.000Z

386

SPLASH: Stanford parallel applications for shared-memory  

Science Conference Proceedings (OSTI)

We present the Stanford Parallel Applications for Shared-Memory (SPLASH), a set of parallel applications for use in the design and evaluation of shared-memory multiprocessing systems. Our goal is to provide a suite of realistic applications that will ...

Jaswinder Pal Singh; Wolf-Dietrich Weber; Anoop Gupta

1992-03-01T23:59:59.000Z

387

Adaptive decentralised control of parallel DC-DC converter systems  

Science Conference Proceedings (OSTI)

In this paper, we develop a robust controller for parallel DC-DC converter system by combining the adaptive backstepping technique and decentralised control. The voltages and currents of all converters are coupled with each other. The parallel DC-DC ...

Jing Zhou

2012-08-01T23:59:59.000Z

388

An HPC component for parallel, heterogeneous, and dynamic unstructured meshes  

Science Conference Proceedings (OSTI)

Multi-physics HPC applications with mixed discretization schemes, adaptive unstructured meshes, and parallel distributed data sets have inherent complexity that must be managed. Design concepts embedded in the mesh data structures will either segregate ... Keywords: adaptivity, data structure, multi-physics, parallel, unstructured mesh

H. Carter Edwards

2007-10-01T23:59:59.000Z

389

Meeting the data challenge: curriculum development for parallel data systems  

Science Conference Proceedings (OSTI)

The emergence of commodity-based high performance computing systems and low-cost storage systems in concert with the continued proliferation of data has created a significant need for technologists with expertise in parallel data systems. The training ... Keywords: curriculum development, high performance computing, parallel data systems

Thomas J. Hacker; John A. Springer

2008-10-01T23:59:59.000Z

390

Recursive modelling in dynamics of delta parallel robot  

Science Conference Proceedings (OSTI)

Recursive matrix relations in kinematics and dynamics of a Delta parallel robot having three revolute actuators are established in this paper. The prototype of the manipulator is a three degrees-of-freedom space mechanism, which consists of a system ... Keywords: Dynamics modelling, Kinematics, Parallel mechanism, Virtual work

Stefan Staicu

2009-03-01T23:59:59.000Z

391

On the parallel simulation of scale-free networks  

Science Conference Proceedings (OSTI)

Scale-free networks have received much attention in recent years due to their prevalence in many important applications such as social networks, biological systems, and the Internet. We consider the use of conservative parallel discrete event simulation ... Keywords: conservative synchronization, discrete event simulation, parallelism, power law degree distribution, scale-free, scale-free degree distribution, scale-free network simulation, simulation synchronization

Robert S. Pienta, Richard M. Fujimoto

2013-05-01T23:59:59.000Z

392

Evaluation of Parallel Domain Decomposition Algorithms Jesus Antonio Izaguirre Paz  

E-Print Network (OSTI)

- rameters (from several tests not reported here) for each method tested. 1 "Tight balance" is when a user;.......................................................................................................................................................................................................................................................................................................................................................................................... .......................................................................................................................................................................................................................................................................................................................................................................................... .......................................................................................................................................................................................................................................................................................................................................................................................... .......................................................................................................................................................................................................................................................................................................................................................................................... .......................................................................................................................................................................................................................................................................................................................................................................................... .......................................................................................................................................................................................................................................................................................................................................................................................... .......................................................................................................................................................................................................................................................................................................................................................................................... .......................................................................................................................................................................................................................................................................................................................................................................................... .......................................................................................................................................................................................................................................................................................................................................................................................... Coords? Tight Balance? Coords? Tight Balance? Coords? Tight Balance? Parallel? Parallel? Partition? Y N Y SAND93-1301, Sandia National Laboratories, Albuquereque, NM, 1993. [Hendrickson and Leland, 1994] Bruce

Izaguirre, Jesús A.

393

A Load Balancing Tool for Distributed Parallel Loops  

Science Conference Proceedings (OSTI)

Large scale applications typically contain parallel loops with many iterates. The iterates of a parallel loop may have variable execution times which translate into performance degradation of an application due to load imbalance. This paper describes ... Keywords: adaptive loop scheduling, dynamic load balancing

Ricolindo L. Cariño; Ioana Banicescu

2005-10-01T23:59:59.000Z

394

Computational Experience with a Software Framework for Parallel Integer Programming  

Science Conference Proceedings (OSTI)

In this paper, we discuss the challenges that arise in parallelizing algorithms for solving generic mixed integer linear programs and introduce a software framework that aims to address these challenges. Although the framework makes few algorithmic assumptions, ... Keywords: branch and bound, branch and cut, integer programming, optimization, parallel algorithm, tree search

Y. Xu; T. K. Ralphs; L. Ladányi; M. J. Saltzman

2009-07-01T23:59:59.000Z

395

A hierarchical component model for large parallel interactive applications  

Science Conference Proceedings (OSTI)

This paper focuses on parallel interactive applications ranging from scientific visualization, to virtual reality or computational steering. Interactivity makes them particular on three main aspects: they are endlessly iterative, use advanced I/O devices, ... Keywords: Components, Composite design pattern, Interactive applications, Parallelism

Jean-Denis Lesage; Bruno Raffin

2012-06-01T23:59:59.000Z

396

Experience on the parallelization of the OASIS3 coupler  

Science Conference Proceedings (OSTI)

This work describes the optimization and parallelization of the OASIS3 coupler. Performance evaluation and profiling have been carried out by means of the CMCC-MED coupled model, developed at the Euro-Mediterranean Centre for Climate Change (CMCC) and ... Keywords: OASIS3, climate models, coupled models, parallel modeling, performance analysis

Italo Epicoco; Silvia Mocavero; Giovanni Aloisio

2010-01-01T23:59:59.000Z

397

Parallel agent-based simulator for influenza pandemic  

Science Conference Proceedings (OSTI)

We have developed a parallel agent-based influenza pandemic simulator, in order to study the influenza spread in a city. In the simulator, the city consists of several towns connected tightly by trains. Residents of the towns walk around places such ... Keywords: agent-based simulation, influenza pandemic, parallel computing

Masaya M. Saito; Seiya Imoto; Rui Yamaguchi; Satoru Miyano; Tomoyuki Higuchi

2011-05-01T23:59:59.000Z

398

Modelling of a Utility Boiler Using Parallel Computing  

Science Conference Proceedings (OSTI)

A mathematical model for the simulation of the turbulent reactive flow and heat transfer in a power station boiler has been parallelized. The mathematical model is based on the numerical solution of the governing equations for mass, momentum, energy ... Keywords: boilers, computational fluid dynamics, discrete ordinates, parallel processing, radiative heat transfer, turbulent reactive flows

P. J. Coelho; P. A. Novo; M. G. Carvalho

1999-03-01T23:59:59.000Z

399

Parallel algorithms for solution of air pollution inverse problems  

Science Conference Proceedings (OSTI)

Parallelization of Marchuk's method for solution of inverse problems based on adjoint equations and dual representation of contaminant concentration functional is considered here. There are N individual adjoint equations independently solved at each ... Keywords: air pollution, domain decomposition, functional decomposition, inverse problems, parallel algorithms

Alexander Starchenko; Elena Panasenko

2010-05-01T23:59:59.000Z

400

Bridging parallel and reconfigurable computing with multilevel PGAS and SHMEM+  

Science Conference Proceedings (OSTI)

Reconfigurable computing (RC) systems based on FPGAs are becoming an increasingly attractive solution to building parallel systems of the future. Applications targeting such systems have demonstrated superior performance and reduced energy consumption ... Keywords: parallel programming, portability, productivity, programming language, programming model, reconfigurable computing

V. Aggarwal; A. George; K. Yalamanchili; C. Yoon; H. Lam; G. Stitt

2009-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "massively parallel microcell-based" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Scheduling parallel programs by work stealing with private deques  

Science Conference Proceedings (OSTI)

Work stealing has proven to be an effective method for scheduling parallel programs on multicore computers. To achieve high performance, work stealing distributes tasks between concurrent queues, called deques, which are assigned to each processor. Each ... Keywords: dynamic load balancing, nested parallelism, work stealing

Umut A. Acar; Arthur Chargueraud; Mike Rainey

2013-08-01T23:59:59.000Z

402

A parallel hybrid optimization algorithm for fitting interatomic potentials  

Science Conference Proceedings (OSTI)

In this work we present the parallel implementation of a hybrid global optimization algorithm assembled specifically to tackle a class of time consuming interatomic potential fitting problems. The resulting objective function is characterized by large ... Keywords: Cluster programming, Hybrid global optimization, Interatomic potential, Irregular task parallelism, Multidimensional search, Particle swarm

C. Voglis, P. E. Hadjidoukas, D. G. Papageorgiou, I. E. Lagaris

2013-12-01T23:59:59.000Z

403

Modeling the energy consumption for concurrent executions of parallel tasks  

Science Conference Proceedings (OSTI)

Programming models using parallel tasks provide portable performance and scalability for modular applications on many high-performance systems. This is achieved by the flexibility of a two-level programming structure supporting mixed task and data parallelism. ... Keywords: communication, energy model, task-based programming

Thomas Rauber; Gudula Rünger

2011-04-01T23:59:59.000Z

404

Partitioning strategies for parallel KIVA-4 engine simulations  

SciTech Connect

Parallel KIVA-4 is described and simulated in four different engine geometries. The Message Passing-Interface (MPl) was used to parallelize KIVA-4. Par itioning strategies ar accesed in light of the fact that cells can become deactivated and activated during the course of an engine simulation which will affect the load balance between processors.

Torres, D J [Los Alamos National Laboratory; Kong, S C [IOWA STATE UNIV

2008-01-01T23:59:59.000Z

405

JASMIN: a parallel software infrastructure for scientific computing  

Science Conference Proceedings (OSTI)

The exponential growth of computer power in the last 10 years is now creating a great challenge for parallel programming toward achieving realistic performance in the field of scientific computing. To improve on the traditional program for numerical ... Keywords: J Adaptive Structured Meshes applications INfrastructure (JASMIN), parallel computing, scientific computing

Zeyao Mo; Aiqing Zhang; Xiaolin Cao; Qingkai Liu; Xiaowen Xu; Hengbin An; Wenbing Pei; Shaoping Zhu

2010-12-01T23:59:59.000Z

406

Computationally efficient implementation of combustion chemistry in parallel PDF calculations  

Science Conference Proceedings (OSTI)

In parallel calculations of combustion processes with realistic chemistry, the serial in situ adaptive tabulation (ISAT) algorithm [S.B. Pope, Computationally efficient implementation of combustion chemistry using in situ adaptive tabulation, Combustion ... Keywords: 07.05.Mh, 46.15.-x, 47.11.-j, Combustion chemistry, Distribution strategy, ISAT, Load balance, Parallel calculation

Liuyan Lu; Steven R. Lantz; Zhuyin Ren; Stephen B. Pope

2009-08-01T23:59:59.000Z

407

Communication-Sensitive Static Dataflow for Parallel Message Passing Applications  

Science Conference Proceedings (OSTI)

Message passing is a very popular style of parallel programming, used in a wide variety of applications and supported by many APIs, such as BSD sockets, MPI and PVM. Its importance has motivated significant amounts of research on optimization and debugging ... Keywords: message-passing, compiler analysis, static analysis, parallel processing, multi-core

Greg Bronevetsky

2009-03-01T23:59:59.000Z

408

Balanced Decomposition for Power System Simulation on Parallel Computers  

E-Print Network (OSTI)

Balanced Decomposition for Power System Simulation on Parallel Computers Felipe Morales, Hugh parallelization strategy is tested in a Parsytec computer incorpo- rating two PowerXplorer systems, each one System. 1 Introduction Power system analysis is intensive in computational terms 1 . In fact, the power

Rudnick, Hugh

409

Seismic studies of a massive hydraulic fracturing experiment  

DOE Green Energy (OSTI)

During a massive hydraulic fracturing experiment carried out at Fenton Hill, New Mexico, 850 microearthquakes, ranging in magnitudes from -3 to 0, were located reliably using arrival times recorded at a set of 5 downhole geophone stations. A subset of these events were located using an upgraded hodogram technique. The seismicity defines a tabular zone with horizontal extent of 900 m, vertical extent of 800 m, and thickness of 150 m. This zone strikes N340/sup 0/E, and dips 75/sup 0/ to the east; its position indicates that no hydraulic connection between the two predrilled wells could be achieved by the fracturing. The distribution of locations obtained from arrival times shows good agreement with those derived from hodograms. Well constrained fault plane solutions were determined for 26 of the larger microearthquakes observed at a surface seismic net. Most solutions display one nearly vertical nodal plane that strikes close to N - S, and a T axis that trends roughly E - W, in agreement with regional indicators of the least principal stress direction. 9 refs., 6 figs.

House, L.; Keppler, H.; Kaieda, H.

1985-01-01T23:59:59.000Z

410

Modeling broadband X-ray absorption of massive star winds  

E-Print Network (OSTI)

We present a method for computing the net transmission of X-rays emitted by shock-heated plasma distributed throughout a partially optically thick stellar wind from a massive star. We find the transmission by an exact integration of the formal solution, assuming the emitting plasma and absorbing plasma are mixed at a constant mass ratio above some minimum radius, below which there is assumed to be no emission. This model is more realistic than either the slab absorption associated with a corona at the base of the wind or the exospheric approximation that assumes all observed X-rays are emitted without attenuation from above the radius of optical depth unity. Our model is implemented in XSPEC as a pre-calculated table that can be coupled to a user-defined table of the wavelength dependent wind opacity. We provide a default wind opacity model that is more representative of real wind opacities than the commonly used neutral ISM tabulation. Preliminary modeling of \\textit{Chandra} grating data indicates that the ...

Leutenegger, Maurice A; Zsargó, Janos; Martell, Erin M; MacArthur, James P; Owocki, Stanley P; Gagné, Marc; Hillier, D John

2010-01-01T23:59:59.000Z

411

Tight LMC massive star clusters R 127 and R 128  

E-Print Network (OSTI)

We study the Large Magellanic Cloud (LMC) star clusters R 127 and R 128 using imaging and spectroscopy obtained at the ESO NTT telescope. An advanced image restoration technique allows us to resolve these two clusters into at least 14 and 33 stars respectively and obtain their photometry. In particular, we show that the core of R 127 is composed of at least four stars and identify the Luminous Blue Variable (LBV) component. The closest neighbor of the LBV (star #8) is 1".5 away. Moreover, from medium dispersion spectroscopy we determine the spectral types for 19 stars in and near both clusters, and in particular present the first spatially resolved observation of the second brightest component of the R 127 cluster (star #3) situated 3".3 from the LBV. By comparing with evolutionary models we also look into the stellar ages. The oldest stars of the cluster are ~ 6-8 Myr old, whereas the most massive star of the region (#7), formed ~ 3 Myr ago as an 80 solar mass star, has turned into an LBV, the ``R 127'' star.

M. Heydari-Malayeri; F. Meynadier; Nolan R. Walborn

2003-01-15T23:59:59.000Z

412

Load Balancing Of Parallel Monte Carlo Transport Calculations  

National Nuclear Security Administration (NNSA)

Load Balancing Of Parallel Load Balancing Of Parallel Monte Carlo Transport Calculations R.J. Procassini, M. J. O'Brien and J.M. Taylor Lawrence Livermore National Laboratory, P. O. Box 808, Livermore, CA 94551 The performance of parallel Monte Carlo transport calculations which use both spatial and particle parallelism is increased by dynamically assigning processors to the most worked domains. Since the particle work load varies over the course of the simulation, each cycle this algorithm determines if dynamic load balancing would speed up the calculation. If load balancing is required, a small number of particle communications are initiated in order to achieve load balance. This method has decreased the parallel run time by more than a factor of three for certain criticality

413

SMARTS: Exploiting Temporal Locality and Parallelism through Vertical Execution  

Science Conference Proceedings (OSTI)

In the solution of large-scale numerical prob- lems, parallel computing is becoming simultaneously more important and more difficult. The complex organization of today's multiprocessors with several memory hierarchies has forced the scientific programmer to make a choice between simple but unscalable code and scalable but extremely com- plex code that does not port to other architectures. This paper describes how the SMARTS runtime system and the POOMA C++ class library for high-performance scientific computing work together to exploit data parallelism in scientific applications while hiding the details of manag- ing parallelism and data locality from the user. We present innovative algorithms, based on the macro -dataflow model, for detecting data parallelism and efficiently executing data- parallel statements on shared-memory multiprocessors. We also desclibe how these algorithms can be implemented on clusters of SMPS.

Beckman, P.; Crotinger, J.; Karmesin, S.; Malony, A.; Oldehoeft, R.; Shende, S.; Smith, S.; Vajracharya, S.

1999-01-04T23:59:59.000Z

414

The Manycore Revolution and Parallel Software Projects at NERSC  

NLE Websites -- All DOE Office Websites (Extended Search)

The Manycore The Manycore Revolution and Parallel Software The Manycore Revolution and Parallel Software | Tags: Math & Computer Science PGAS.jpg Key Challenges: A new software ecosystem is expected to emerge over the next decade to support changes brought about by manycore and multicore systems. The question is whether languages like Unified Parallel C (UPC), which runs on all of the major DOE Office of Science platforms, can provide the best path forward, lowering the barrier to entry for parallel computing and making parallel machines more attractive as commercial products. Why it Matters: Although MPI is currently the de facto standard for programming supercomputers, partitioned global address space (PGAS) languages offer advantages in both programmability and performance. They

415

Parallel Computing in the 1990's: Attacking the Software Problem  

E-Print Network (OSTI)

It is today's general wisdom that the productive use of parallel architectures depends crucially on the availability of powerful development tools and run-time environments. In this paper, we systematically discuss the fundamental software problems encountered in programming parallel architectures, in particular those with distributed resources. All these problems need to be solved, if efficient and convenient use of parallel machines is to be guaranteed. We present a five phases model of parallel application program development, which describes the required efforts in parallel programming by means of four transformation steps: problem analysis, algorithm design, implementation, and mapping. The major part of the paper is dedicated to the description of three research projects which focus on the last three transformation steps: SKELETON, a tool for providing improved algorithmic support for the application-oriented programmer, SPADE, an integrated development and run-time environment, ...

J.E. Boillat; H. Burkhart; K. M. Decker; P. G. Kropf

1991-01-01T23:59:59.000Z

416

Broadcasting collective operation contributions throughout a parallel computer  

Science Conference Proceedings (OSTI)

Methods, systems, and products are disclosed for broadcasting collective operation contributions throughout a parallel computer. The parallel computer includes a plurality of compute nodes connected together through a data communications network. Each compute node has a plurality of processors for use in collective parallel operations on the parallel computer. Broadcasting collective operation contributions throughout a parallel computer according to embodiments of the present invention includes: transmitting, by each processor on each compute node, that processor's collective operation contribution to the other processors on that compute node using intra-node communications; and transmitting on a designated network link, by each processor on each compute node according to a serial processor transmission sequence, that processor's collective operation contribution to the other processors on the other compute nodes using inter-node communications.

Faraj, Ahmad (Rochester, MN)

2012-02-21T23:59:59.000Z

417

Broadcasting collective operation contributions throughout a parallel computer  

DOE Patents (OSTI)

Methods, systems, and products are disclosed for broadcasting collective operation contributions throughout a parallel computer. The parallel computer includes a plurality of compute nodes connected together through a data communications network. Each compute node has a plurality of processors for use in collective parallel operations on the parallel computer. Broadcasting collective operation contributions throughout a parallel computer according to embodiments of the present invention includes: transmitting, by each processor on each compute node, that processor's collective operation contribution to the other processors on that compute node using intra-node communications; and transmitting on a designated network link, by each processor on each compute node according to a serial processor transmission sequence, that processor's collective operation contribution to the other processors on the other compute nodes using inter-node communications.

Faraj, Ahmad (Rochester, MN)

2012-02-21T23:59:59.000Z

418

A data distributed, parallel algorithm for ray-traced volume rendering  

Science Conference Proceedings (OSTI)

This paper presents a divide-and-conquer ray-traced volume rendering algorithm and its implementation on networked workstations and a massively parallel computer, the Connection Machine CM-5. This algorithm distributes the data and the computational load to individual processing units to achieve fast, high-quality rendering of high-resolution data, even when only a modest amount of memory is available on each machine. The volume data, once distributed, is left intact. The processing nodes perform local ray-tracing of their subvolume concurrently. No communication between processing units is needed during this locally ray-tracing process. A subimage is generated by each processing unit and the final image is obtained by compositing subimages in the proper order, which can be determined a priori. Implementations and tests on a group of networked workstations and on the Thinking Machines CM-5 demonstrate the practicality of our algorithm and expose different performance tuning issues for each platform. We use data sets from medical imaging and computational fluid dynamics simulations in the study of this algorithm.

Ma, Kwan-Liu; Painter, J.S. [Utah Univ., Salt Lake City, UT (United States). Dept. of Computer Science; Hansen, C.D.; Krogh, M.F. [Los Alamos National Lab., NM (United States)

1993-03-30T23:59:59.000Z

419

Field theory of massive and massless vector particles in the Duffin - Kemmer - Petiau formalism  

E-Print Network (OSTI)

Field theory of massive and massless vector particles is considered in the first-order formalism. The Hamiltonian form of equations is obtained after the exclusion of non-dynamical components. We obtain the canonical and symmetrical Belinfante energy-momentum tensors and their nonzero traces. We note that the dilatation symmetry is broken in the massive case but in the massless case the modified dilatation current is conserved. The canonical quantization is performed and the propagator of the massive fields is found in the Duffin - Kemmer - Petiau formalism.

S. I. Kruglov

2010-09-24T23:59:59.000Z

420

Constrained Dynamics of Universally Coupled Massive Spin 2-spin 0 Gravities  

E-Print Network (OSTI)

The 2-parameter family of massive variants of Einstein's gravity (on a Minkowski background) found by Ogievetsky and Polubarinov by excluding lower spins can also be derived using universal coupling. A Dirac-Bergmann constrained dynamics analysis seems not to have been presented for these theories, the Freund-Maheshwari-Schonberg special case, or any other massive gravity beyond the linear level treated by Marzban, Whiting and van Dam. Here the Dirac-Bergmann apparatus is applied to these theories. A few remarks are made on the question of positive energy. Being bimetric, massive gravities have a causality puzzle, but it appears soluble by the introduction and judicious use of gauge freedom.

J. Brian Pitts

2006-01-25T23:59:59.000Z

Note: This page contains sample records for the topic "massively parallel microcell-based" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Samatova et. al. Parallel OutofCore EP Calculation Parallel Outofcore Algorithm for GenomeScale Enumeration of  

E-Print Network (OSTI)

Samatova et. al. Parallel Out­of­Core EP Calculation 1 Parallel Out­of­core Algorithm for Genome­Scale Enumeration of Metabolic Systemic Pathways * Nagiza F. Samatova 1 , Al Geist 1 , George Ostrouchov 1 The elucidation of genome­scale metabolic networks (Karp et. al, 1996; Selkov et. al, 1997, 1998; Overbeek et. al

422

Parallel transport of long mean-free-path plasma along open magnetic field lines: Parallel heat flux  

SciTech Connect

In a long mean-free-path plasma where temperature anisotropy can be sustained, the parallel heat flux has two components with one associated with the parallel thermal energy and the other the perpendicular thermal energy. Due to the large deviation of the distribution function from local Maxwellian in an open field line plasma with low collisionality, the conventional perturbative calculation of the parallel heat flux closure in its local or non-local form is no longer applicable. Here, a non-perturbative calculation is presented for a collisionless plasma in a two-dimensional flux expander bounded by absorbing walls. Specifically, closures of previously unfamiliar form are obtained for ions and electrons, which relate two distinct components of the species parallel heat flux to the lower order fluid moments such as density, parallel flow, parallel and perpendicular temperatures, and the field quantities such as the magnetic field strength and the electrostatic potential. The plasma source and boundary condition at the absorbing wall enter explicitly in the closure calculation. Although the closure calculation does not take into account wave-particle interactions, the results based on passing orbits from steady-state collisionless drift-kinetic equation show remarkable agreement with fully kinetic-Maxwell simulations. As an example of the physical implications of the theory, the parallel heat flux closures are found to predict a surprising observation in the kinetic-Maxwell simulation of the 2D magnetic flux expander problem, where the parallel heat flux of the parallel thermal energy flows from low to high parallel temperature region.

Guo Zehua; Tang Xianzhu [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2012-06-15T23:59:59.000Z

423

Eighth SIAM conference on parallel processing for scientific computing: Final program and abstracts  

SciTech Connect

This SIAM conference is the premier forum for developments in parallel numerical algorithms, a field that has seen very lively and fruitful developments over the past decade, and whose health is still robust. Themes for this conference were: combinatorial optimization; data-parallel languages; large-scale parallel applications; message-passing; molecular modeling; parallel I/O; parallel libraries; parallel software tools; parallel compilers; particle simulations; problem-solving environments; and sparse matrix computations.

NONE

1997-12-31T23:59:59.000Z

424

STAR FORMATION IN MASSIVE CLUSTERS VIA BONDI ACCRETION  

SciTech Connect

Essentially all stars form in giant molecular clouds (GMCs). However, inside GMCs, most of the gas does not participate in star formation; rather, denser gas accumulates in clumps in the GMC, with the bulk of the stars in a given GMC forming in a few of the most massive clumps. In the Milky Way, these clumps have masses M{sub cl} {approx}< 5 Multiplication-Sign 10{sup -2} of the GMC, radii r{sub cl} {approx} 1 pc, and free-fall times {tau}{sub cl} {approx} 2 Multiplication-Sign 10{sup 5} yr. We show that clumps inside GMCs should accrete at a modified Bondi accretion rate, which depends on clump mass as M-dot{sub cl}{approx}M{sub cl}{sup 5/4}. This rate is initially rather slow, usually slower than the initial star formation rate inside the clump (we adopt the common assumption that inside the clump, M-dot{sub *}={epsilon}{sub ff}M{sub cl}/{tau}{sub cl}, with {epsilon}{sub ff} Almost-Equal-To 0.017). However, after {approx}2 GMC free-fall times {tau}{sub GMC}, the clump accretion rate accelerates rapidly; formally, the clump can accrete the entire GMC in {approx}3{tau}{sub GMC}. At the same time, the star formation rate accelerates, tracking the Bondi accretion rate. If the GMC is disrupted by feedback from the largest clump, half the stars in that clump form in the final {tau}{sub GMC} before the GMC is disrupted. The theory predicts that the distribution of effective star formation rates, measured per GMC free-fall time, is broad, ranging from {approx}0.001 up to 0.1 or larger and that the mass spectrum of star clusters is flatter than that of clumps, consistent with observations.

Murray, Norman; Chang, Philip, E-mail: murray@cita.utoronto.ca, E-mail: pchang@cita.utoronto.ca [Canadian Institute for Theoretical Astrophysics, 60 St. George Street, University of Toronto, Toronto, ON M5S 3H8 (Canada)

2012-02-10T23:59:59.000Z

425

Evolution of massive stars losing mass and angular momentum supergiants  

SciTech Connect

Evolutionary sequences have been computed to central helium exhaustion for massive Population I star models with initial masses of 40, 60, 80, and 100 M/sub sun/. Mass loss occurs through radiatively driven winds and through the effects of nonthermal winds generated both by rotational shear turbulence during the mainsequence (MS) phase and by the acoustic energy flux from the convective envelope during the red supergiant phase. The size of the convective envelope in the red supergiant phase is found to depend on the mass loss history of the star, through the effect of mass loss on the position of the hydrogen shell source (HSS) and on the opacity of the envelope above the HSS. Previous evolutionary calculations have shown that, for low mass loss rates, a blue loop forms when the HSS contacts the discontinuity at the base of the convective envelope. In contrast, the higher mass loss rates considered here produce a blue loop only if sufficient mass loss occurs during the red supergiant phase to eliminate the convective envelope entirely. On the other hand, sufficiently high mass loss rates during the MS phase can remove most of the hydrogen-rich envelope, and then the red supergiant phase does not occur. In these models the mass loss and evolutionary patterns for a star depend on its initial rotational speed, which in actual stars is expected to vary from star to star. The observed blue-to-red supergiant ratios are then interpreted as weighted means of different evolutionary patterns resulting from a spread of initial rotational speeds. The same interpretation may extend to Wolf-Rayet stars.

Sreenivasan, S.R.; Wilson, W.J.F.

1985-03-15T23:59:59.000Z

426

Evolution of Massive Protostars with High Accretion Rates  

E-Print Network (OSTI)

Formation of massive stars by accretion requires a high accretion rate of > 10^-4 M_sun/yr to overcome the radiation pressure barrier of the forming stars. Here, we study evolution of protostars accreting at such high rates, by solving the structure of the central star and the inner accreting envelope simultaneously. The protostellar evolution is followed starting from small initial cores until their arrival at the stage of the Zero-Age Main Sequence (ZAMS) stars. An emphasis is put on evolutionary features different from those with a low accretion rate of 10^-5 M_sun/yr, which is presumed in the standard scenario for low-mass star formation. With the high accretion rate of 10^-3 M_sun/yr, the protostellar radius becomes very large and exceeds 100 R_sun. It is not until the stellar mass reaches 40 M_sun that hydrogen burning begins and the protostar reaches the ZAMS phase, and this ZAMS arrival mass increases with the accretion rate. At a very high accretion rate of > 3 x 10^-3 M_sun/yr, the total luminosity of the protostar becomes so high that the resultant radiation pressure inhibits the growth of the protostars under steady accretion before reaching the ZAMS stage. Therefore, the evolution under the critical accretion rate 3 x 10^-3 M_sun/yr gives the upper mass limit of possible pre-main-sequence stars at 60 M_sun. The upper mass limit of MS stars is also set by the radiation pressure onto the dusty envelope under the same accretion rate at 250 M_sun. We also propose that the central source enshrouded in the Orion KL/BN nebula has effective temperature and luminosity consistent with our model, and is a possible candidate for such protostars growing under the high accretion rate. (abridged)

Takashi Hosokawa; Kazuyuki Omukai

2008-06-25T23:59:59.000Z

427

A faint galaxy redshift survey behind massive clusters  

SciTech Connect

This thesis is concerned with the gravitational lensing effect by massive galaxy clusters. We have explored a new technique for measuring galaxy masses and for detecting high-z galaxies by their optical colors. A redshift survey has been obtained at the Keck for a magnitude limited sample of objects (I<23) behind three clusters, A1689, A2390, and A2218 within a radius of 0.5M pc. For each cluster we see both a clear trend of increasing flux and redshift towards the center. This behavior is the result of image magnifications, such that at fixed redshift one sees further down the luminosity function. The gradient of this magnification is, unlike measurements of image distortion, sensitive to the mass profile, and found to depart strongly from a pure isothermal halo. We have found that V RI color selection can be used effectively as a discriminant for finding high-z galaxies behind clusters and present five 4.1 < z < 5.1 spectra which are of very high quality due to their high mean magnification of {approximately}20, showing strong, visibly-saturated interstellar metal lines in some cases. We have also investigated the radio ring lens PKS 1830-211, locating the source and multiple images and detected molecular absorption at mm wavelengths. Broad molecular absorption of width 1/40kms is found toward the southwest component only, where surprisingly it does not reach the base of the continuum, which implies incomplete coverage of the SW component by molecular gas, despite the small projected size of the source, less than 1/8h pc at the absorption redshift.

Frye, Brenda

1999-12-01T23:59:59.000Z

428

Xyce parallel electronic simulator : users' guide. Version 5.1.  

Science Conference Proceedings (OSTI)

This manual describes the use of the Xyce Parallel Electronic Simulator. Xyce has been designed as a SPICE-compatible, high-performance analog circuit simulator, and has been written to support the simulation needs of the Sandia National Laboratories electrical designers. This development has focused on improving capability over the current state-of-the-art in the following areas: (1) Capability to solve extremely large circuit problems by supporting large-scale parallel computing platforms (up to thousands of processors). Note that this includes support for most popular parallel and serial computers. (2) Improved performance for all numerical kernels (e.g., time integrator, nonlinear and linear solvers) through state-of-the-art algorithms and novel techniques. (3) Device models which are specifically tailored to meet Sandia's needs, including some radiation-aware devices (for Sandia users only). (4) Object-oriented code design and implementation using modern coding practices that ensure that the Xyce Parallel Electronic Simulator will be maintainable and extensible far into the future. Xyce is a parallel code in the most general sense of the phrase - a message passing parallel implementation - which allows it to run efficiently on the widest possible number of computing platforms. These include serial, shared-memory and distributed-memory parallel as well as heterogeneous platforms. Careful attention has been paid to the specific nature of circuit-simulation problems to ensure that optimal parallel efficiency is achieved as the number of processors grows. The development of Xyce provides a platform for computational research and development aimed specifically at the needs of the Laboratory. With Xyce, Sandia has an 'in-house' capability with which both new electrical (e.g., device model development) and algorithmic (e.g., faster time-integration methods, parallel solver algorithms) research and development can be performed. As a result, Xyce is a unique electrical simulation capability, designed to meet the unique needs of the laboratory.

Mei, Ting; Rankin, Eric Lamont; Thornquist, Heidi K.; Santarelli, Keith R.; Fixel, Deborah A.; Coffey, Todd Stirling; Russo, Thomas V.; Schiek, Richard Louis; Keiter, Eric Richard; Pawlowski, Roger Patrick

2009-11-01T23:59:59.000Z

429

Workers Pour 1 Million Gallons of Grout into Massive Tanks | Department of  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Workers Pour 1 Million Gallons of Grout into Massive Tanks Workers Pour 1 Million Gallons of Grout into Massive Tanks Workers Pour 1 Million Gallons of Grout into Massive Tanks May 15, 2012 - 12:00pm Addthis Cement trucks transport a specially formulated grout that is pumped into the waste tanks. Cement trucks transport a specially formulated grout that is pumped into the waste tanks. AIKEN, S.C. - Workers have poured more than 1 million gallons of a cement-like grout into two underground radioactive waste tanks, moving the Savannah River Site (SRS) nearer to closing the massive structures. SRS and liquid waste contractor Savannah River Remediation are working to fill the 1.3-million-gallon Tanks 18 and 19 with grout, a project that began April 2. Grouting of the tanks, ancillary piping and equipment is scheduled for completion in late summer.

430

CAMEO: enabling social networks for massively multiplayer online games through continuous analytics and cloud computing  

Science Conference Proceedings (OSTI)

Millions of people play Massively Multiplayer Online Games (MMOGs) and participate in the social networks built around MMOGs daily. These players turn into a collaborative community to exchange game news, advice, and expertise, but in return expect support ...

Alexandru Iosup; Adrian L?sc?teu; Nicolae ??pu?

2010-11-01T23:59:59.000Z

431

Effects of a new 3-alpha reaction on the s-process in massive stars  

SciTech Connect

Effect of a new 3-alpha reaction rate on the s-process during the evolution of a massive star of 25 solar mass is investigated for the first time, because the s-process in massive stars have been believed to be established with only minor change. We find that the s-process with use of the new rate during the core helium burning is very inefficient compared to the case with the previous 3-alpha rate. However, the difference of the overproduction is found to be largely compensated by the subsequent carbon burning. Since the s-process in massive stars has been attributed so far to the neutron irradiation during core helium burning, our finding reveals for the first time the importance of the carbon burning for the s-process during the evolution of massive stars.

Kikuch, Yukihiro; Ono, Masaomi; Matsuo, Yasuhide; Hashimoto, Masa-aki; Fujimoto, Shin-ichiro [Department of physics, Kyushu University, Fukuoka 812-8581 (Japan); Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan); Department of physics, Kyushu University, Fukuoka 812-8581 (Japan); Kumamoto National College of Technology, Kumamoto 861-1102 (Japan)

2012-11-12T23:59:59.000Z

432

Customer research, customer-driven design, and business strategy in Massively Multiplayer Online Games  

E-Print Network (OSTI)

This thesis is a part of an exploration of how the relationships between the customers of Massively Multiplayer Online Games (MMOGs) shape customer experience, and can be used to diminish customer churn and improve customer ...

Andrivet, Sébastien

2007-01-01T23:59:59.000Z

433

Efficient Range and Join Query Processing in Massively Distributed Peer-to-Peer Networks.  

E-Print Network (OSTI)

??Peer-to-peer (P2P) has become a modern distributed computing architecture that supports massively large-scale data management and query processing. Complex query operators such as range operator… (more)

Wang, Qiang

2008-01-01T23:59:59.000Z

434

A Minimum Column Density of 1 g cm^-2 for Massive Star Formation  

E-Print Network (OSTI)

Massive stars are very rare, but their extreme luminosities make them both the only type of young star we can observe in distant galaxies and the dominant energy sources in the universe today. They form rarely because efficient radiative cooling keeps most star-forming gas clouds close to isothermal as they collapse, and this favors fragmentation into stars ~ 1 g cm^-2 can avoid fragmentation and form massive stars. This threshold, and the environmental variation of the stellar initial mass function (IMF) that it implies, naturally explain the characteristic column densities of massive star clusters and the difference between the radial profiles of Halpha and UV emission in galactic disks. The existence of a threshold also implies that there should be detectable variations in the IMF with environment within the Galaxy and in the characteristic column densities of massive star clusters between galaxies, and that star formation rates in some galactic environments may have been systematically underestimated.

Mark R. Krumholz; Christopher F. McKee

2008-01-02T23:59:59.000Z

435

Iterational retiming: Maximize iteration-level parallelism for nested loops  

E-Print Network (OSTI)

Nested loops are the most critical sections in many scientific and Digital Signal Processing (DSP) applications. It is important to study effective and efficient transformation techniques to increase parallelism for nested loops. In this paper, we propose a novel technique, iterational retiming, that can satisfy any given timing constraint by achieving full parallelism for iterations in a partition. Theorems and efficient algorithms are proposed for iterational retiming. The experimental results show that iterational retiming is a promising technique for parallel embedded systems. It can achieve 87% improvement over software pipelining and 88 % improvement over loop unfolding on average.

Chun Xue; Zili Shao; Meilin Liu; Edwin H. -m. Sha

2005-01-01T23:59:59.000Z

436

Parallel Condensing System As A Heat Sink For Power Plants  

E-Print Network (OSTI)

Conventional heat sink technologies of use the condenser/cooling tower arrangement or an air cooled condenser for condensing exhaust steam from steam turbines. Each of these two systems have certain advantages as well as disadvantages. This paper discusses an alternate heat sink technology known as the Parallel Condensing System which is a combination of the cooling tower and the air cooled technologies. The Parallel Condensing System offers the advantages associated the conventional technologies but minimizes the disadvantages. As a result the Parallel Condensing System can offer greater value to the plant operator under certain circumstances.

Akhtar, S. Z.

2001-05-01T23:59:59.000Z

437

Coarse-grid selection for parallel algebraic multigrid  

SciTech Connect

The need to solve linear systems arising from problems posed on extremely large, unstructured grids has sparked great interest in parallelizing algebraic multigrid (AMG) To date, however, no parallel AMG algorithms exist We introduce a parallel algorithm for the selection of coarse-grid points, a crucial component of AMG, based on modifications of certain paallel independent set algorithms and the application of heuristics designed to insure the quality of the coarse grids A prototype serial version of the algorithm is implemented, and tests are conducted to determine its effect on multigrid convergence, and AMG complexity

Cleary, A. J., LLNL

1998-06-01T23:59:59.000Z

438

TECA: A Parallel Toolkit for Extreme Climate Analysis  

SciTech Connect

We present TECA, a parallel toolkit for detecting extreme events in large climate datasets. Modern climate datasets expose parallelism across a number of dimensions: spatial locations, timesteps and ensemble members. We design TECA to exploit these modes of parallelism and demonstrate a prototype implementation for detecting and tracking three classes of extreme events: tropical cyclones, extra-tropical cyclones and atmospheric rivers. We process a modern TB-sized CAM5 simulation dataset with TECA, and demonstrate good runtime performance for the three case studies.

Prabhat, Mr; Ruebel, Oliver; Byna, Surendra; Wu, Kesheng; Li, Fuyu; Wehner, Michael; Bethel, E. Wes

2012-03-12T23:59:59.000Z

439

The canonical transformation and massive CSW vertices for MHV-SQCD  

E-Print Network (OSTI)

The similarity of massive CSW scalar vertices and quark vertices can be understood using a kind of light-cone SUSY transformation presented in this paper. We also show that the canonical transformation generating the MHV-SQCD lagrangian, can be fixed by applying this light-cone SUSY transformation to the canonical transformation for MHV-QCD obtained in paper arxiv:0805.0239. Most of the massive CSW vertices for SQCD can also be pinned down in this way.

Tim R. Morris; Zhiguang Xiao

2008-10-21T23:59:59.000Z

440

The evolution of massive stars: a selection of facts and questions  

E-Print Network (OSTI)

In the present paper we discuss a selection of facts and questions related to observations and evolutionary calculations of massive single stars and massive stars in interacting binaries. We focus on the surface chemical abundances, the role of stellar winds, the early Be-stars, the high mass X-ray binaries, the effects of rotation on stellar evolution. Finally, we present an unconventionally formed object scenario (a UFO-scenario) of WR binaries in dense stellar environments.

Vanbeveren, D

2004-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "massively parallel microcell-based" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

The evolution of massive stars: a selection of facts and questions  

E-Print Network (OSTI)

In the present paper we discuss a selection of facts and questions related to observations and evolutionary calculations of massive single stars and massive stars in interacting binaries. We focus on the surface chemical abundances, the role of stellar winds, the early Be-stars, the high mass X-ray binaries, the effects of rotation on stellar evolution. Finally, we present an unconventionally formed object scenario (a UFO-scenario) of WR binaries in dense stellar environments.

Dany Vanbeveren

2004-10-01T23:59:59.000Z

442

The role of low-mass star clusters in massive star formation. The Orion Case  

E-Print Network (OSTI)

To distinguish between the different theories proposed to explain massive star formation, it is crucial to establish the distribution, the extinction, and the density of low-mass stars in massive star-forming regions. We analyze deep X-ray observations of the Orion massive star-forming region using the Chandra Orion Ultradeep Project (COUP) catalog. We studied the stellar distribution as a function of extinction, with cells of 0.03 pc x 0.03 pc, the typical size of protostellar cores. We derived stellar density maps and calculated cluster stellar densities. We found that low-mass stars cluster toward the three massive star-forming regions: the Trapezium Cluster (TC), the Orion Hot Core (OHC), and OMC1-S. We derived low-mass stellar densities of 10^{5} stars pc^{-3} in the TC and OMC1-S, and of 10^{6} stars pc^{-3} in the OHC. The close association between the low-mass star clusters with massive star cradles supports the role of these clusters in the formation of massive stars. The X-ray observations show for ...

Rivilla, V M; Jimenez-Serra, I; Rodriguez-Franco, A

2013-01-01T23:59:59.000Z

443

Parallel fault backtracing for calculation of fault coverage  

Science Conference Proceedings (OSTI)

A new improved method for calculation of fault coverage with parallel fault backtracing in combinational circuits is proposed. The method is based on structurally synthesized BDDs (SSBDD) which represent gate-level circuits at higher, macro level where ...

Raimund Ubar; Sergei Devadze; Jaan Raik; Artur Jutman

2008-01-01T23:59:59.000Z

444

Reducing Concurrency Bottlenecks in Parallel I/O Workloads  

SciTech Connect

To enable high performance parallel checkpointing we introduced the Parallel Log Structured File System (PLFS). PLFS is middleware interposed on the file system stack to transform concurrent writing of one application file into many non-concurrently written component files. The promising effectiveness of PLFS makes it important to examine its performance for workloads other than checkpoint capture, notably the different ways that state snapshots may be later read, to make the case for using PLFS in the Exascale I/O stack. Reading a PLFS file involved reading each of its component files. In this paper we identify performance limitations on broader workloads in an early version of PLFS, specifically the need to build and distribute an index for the overall file, and the pressure on the underlying parallel file system's metadata server, and show how PLFS's decomposed components architecture can be exploited to alleviate bottlenecks in the underlying parallel file system.

Manzanares, Adam C. [Los Alamos National Laboratory; Bent, John M. [Los Alamos National Laboratory; Wingate, Meghan [Los Alamos National Laboratory

2011-01-01T23:59:59.000Z

445

Protein structure prediction by a data-level parallel algorithm  

Science Conference Proceedings (OSTI)

We have developed a software system, PHI-PSI, on the Connection Machine that uses a parallel algorithm to retrieve and use information from a database of 112 known protein structures (selected from the Brookhaven Protein Databank) to ...

X. Zhang; D. Waltz; J. P. Mesirov

1989-08-01T23:59:59.000Z

446

Parallel and Fully Recursive Multifrontal Supernodal Sparse Cholesky  

Science Conference Proceedings (OSTI)

We describe the design, implementation, and performance of a new parallel sparse Cholesky factorization code. The code uses a supernodal multifrontal factorization strategy. Operations on small dense submatrices are performed using new dense-matrix subroutines ...

Dror Irony; Gil Shklarski; Sivan Toledo

2002-04-01T23:59:59.000Z

447

Generating Parallel Programs from the Wavefront Design Pattern  

Science Conference Proceedings (OSTI)

Object-oriented programming, design patterns, and frameworks are common techniques that have been used to reduce the complexity of sequential programming. We have applied these techniques to the more difficult domain of parallel programming. This paper ...

John Anvik; Steve MacDonald; Duane Szafron; Jonathan Schaeffer; Steven Bromling; Kai Tan

2002-04-01T23:59:59.000Z

448

Optimizing Mutual Exclusion Synchronization in Explicitly Parallel Programs  

Science Conference Proceedings (OSTI)

We present two new compiler optimizations for explicitly parallel programs based on the CSSAME form: Lock-Independent Code Motion (LICM) and Mutex Body Localization (MBL). We have implemented these optimizations on top of the SUIF framework and present ...

Diego Novillo; Ronald C. Unrau; Jonathan Schaeffer

2000-05-01T23:59:59.000Z

449

The cost of conservative synchronization in parallel discrete event simulations  

Science Conference Proceedings (OSTI)

This paper analytically studies the performance of a synchronous conservative parallel discrete-event simulation protocol. The class of models considered simulates activity in a physical domain, and possesses a limited ability to predict future behavior. ... Keywords: conservative synchronization

David M. Nicol

1993-04-01T23:59:59.000Z

450

Performance driven multi-objective distributed scheduling for parallel computations  

Science Conference Proceedings (OSTI)

With the advent of many-core architectures and strong need for Petascale (and Exascale) performance in scientific domains and industry analytics, efficient scheduling of parallel computations for higher productivity and performance has become very important. ...

Ankur Narang; Abhinav Srivastava; Naga Praveen Kumar Katta; Rudrapatna K. Shyamasundar

2011-07-01T23:59:59.000Z

451

An interactive parallel programming environment applied in atmospheric science  

SciTech Connect

This article introduces an interactive parallel programming environment (IPPE) that simplifies the generation and execution of parallel programs. One of the tasks of the environment is to generate message-passing parallel programs for homogeneous and heterogeneous computing platforms. The parallel programs are represented by using visual objects. This is accomplished with the help of a graphical programming editor that is implemented in Java and enables portability to a wide variety of computer platforms. In contrast to other graphical programming systems, reusable parts of the programs can be stored in a program library to support rapid prototyping. In addition, runtime performance data on different computing platforms is collected in a database. A selection process determines dynamically the software and the hardware platform to be used to solve the problem in minimal wall-clock time. The environment is currently being tested on a Grand Challenge problem, the NASA four-dimensional data assimilation system.

Laszewski, G. von

1996-12-31T23:59:59.000Z

452

Parallels between Statistical Issues in Medical and Meteorological Experimentation  

Science Conference Proceedings (OSTI)

The methodology of experimentation, randomization, and statistical analysis in weather modification has many parallels in clinical trials, such as the need for randomization, and the question of inclusion or exclusion of units assigned to be ...

K. Ruben Gabriel

2000-11-01T23:59:59.000Z

453

Scalable fault tolerant protocol for parallel runtime environments  

Science Conference Proceedings (OSTI)

The number of processors embedded on high performance computing platforms is growing daily to satisfy users desire for solving larger and more complex problems. Parallel runtime environments have to support and adapt to the underlying libraries and hardware ...

Thara Angskun; Graham E. Fagg; George Bosilca; Jelena Pješivac–Grbovi?; Jack J. Dongarra

2006-09-01T23:59:59.000Z

454

Parallel execution of multi-set constraint rewrite rules  

Science Conference Proceedings (OSTI)

Multi-set constraint rewriting allows for a highly parallel computational model and has been used in a multitude of application domains such as constraint solving, agent specification etc. Rewriting steps can be applied simultaneously as long as they ...

Martin Sulzmann; Edmund S. L. Lam

2008-07-01T23:59:59.000Z

455

Straight, no chaser : drawing a parallel between architecture and music  

E-Print Network (OSTI)

Architecture and music share the same vocabularies: rhythm, proportion, harmony, repetition, contrast, etc, and contain similar structure in terms of composition and spatial characteristics, Given these parallels, how can ...

Yeh, Chih-Jen

1996-01-01T23:59:59.000Z

456

Parallelizing Black Oil Reservoir Simulation Systems for SMP Machines  

Science Conference Proceedings (OSTI)

In this paper we discuss the parallelization for SMPmachines of black oil reservoir simulation programs. Areservoir simulator is a sophisticated computer programused to predict the future performance of a reservoirbased on its current state and past ...

Fabrício A. B. Silva; Ernesto P. Lopes; Eliana P. L. Aude; Flavio Mendes; Henrique Serdeira; Julio Silveira

2003-03-01T23:59:59.000Z

457

A mechanism for efficient debugging of parallel programs  

Science Conference Proceedings (OSTI)

This paper addresses the design and implementation of an integrated debugging system for parallel programs running on shared memory multi-processors (SMMP). We describe the use of flowback analysis to provide information on causal relationships ...

B. P. Miller; Jong-Deok Choi

1988-07-01T23:59:59.000Z

458

A mechanism for efficient debugging of parallel programs  

Science Conference Proceedings (OSTI)

This paper addresses the design and implementation of an integrated debugging system for parallel programs running on shared memory multi-processors (SMMP). We describe the use of flowback analysis to provide information on causal relationships ...

Barton P. Miller; Jong-Deok Choi

1989-01-01T23:59:59.000Z

459

Provably good race detection that runs in parallel  

E-Print Network (OSTI)

A multithreaded parallel program that is intended to be deterministic may exhibit nondeterminism clue to bugs called determinacy races. A key capability of race detectors is to determine whether one thread executes logically ...

Fineman, Jeremy T

2005-01-01T23:59:59.000Z

460

K.L.: Parallel evolutionary algorithms on graphics processing unit  

E-Print Network (OSTI)

Abstract- Evolutionary Algorithms (EAs) are effective and robust methods for solving many practical problems such as feature selection, electrical circuits synthesis, and data mining. However, they may execute for a long time for some difficult problems, because several fitness evaluations must be performed. A promising approach to overcome this limitation is to parallelize these algorithms. In this paper, we propose to implement a parallel EA on consumer-level graphics cards. We perform experiments to compare our parallel EA with an ordinary EA and demonstrate that the former is much more effective than the latter. Since consumer-level graphics cards are available in ubiquitous personal computers and these computers are easy to use and manage, more people will be able to use our parallel algorithm to solve their problems encountered in real-world applications. 1

Man-leung Wong

2005-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "massively parallel microcell-based" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Predicting Performance Impacts due to Resolution Changes in Parallel Simulations  

Science Conference Proceedings (OSTI)

Multi-resolution models are often used to accelerate simulation-based analysis without significantly impacting the fidelity of the simulations. We have developed a web-enabled, component-based, multi-resolution modeling and Time Warp synchronized parallel ...

Dhananjai M. Rao; Philip A. Wilsey

2008-10-01T23:59:59.000Z

462

A parallel algorithm for computing the spectrum of CH5+  

Science Conference Proceedings (OSTI)

We present a parallelized contracted basis-iterative calculation of vibrational energy levels of CH$_5^+$ (a 12D calculation). We use Radau polyspherical coordinates and basis functions that are products of eigenfunctions of bend and stretch Hamiltonians. ...

Xiao-Gang Wang; Tucker Carrington

2009-06-01T23:59:59.000Z

463

Asynchronous parallel reliefboard computation for scene object approximation  

Science Conference Proceedings (OSTI)

We present a parallel algorithm for the rendering of complex three-dimensional scenes. The algorithm runs across heterogeneous architectures of PC-clusters consisting of a visualization-node, equipped with a powerful graphics adapter, and cluster nodes ...

Tim Süß; Claudius Jähn; Matthias Fischer

2010-05-01T23:59:59.000Z

464

Fuzzy ART neural network parallel computing on the GPU  

Science Conference Proceedings (OSTI)

Graphics Processing Units (GPUs) have evolved into powerful programmable processors, faster than Central Processing Units (CPUs) regarding the execution of parallel algorithms. In this paper, an implementation of a Fuzzy ART Neural Network on the GPU ...

Mario Martínez-Zarzuela; Francisco Javier Díaz Pernas; Josél Fernando Dííez Higuera; Míriam Antón Rodríguez

2007-06-01T23:59:59.000Z

465

Parallel Electric Field Spectrum of Solar Wind Turbulence  

E-Print Network (OSTI)

By searching through more than 10 satellite-years of THEMIS and Cluster data, three reliable examples of parallel electric field turbulence in the undisturbed solar wind have been found. The perpendicular and parallel electric field spectra in these examples have similar shapes and amplitudes, even at large scales (frequencies below the ion gyroscale) where Alfvenic turbulence with no parallel electric field component is thought to dominate. The spectra of the parallel electric field fluctuations are power laws with exponents near -5/3 below the ion scales (~ 0.1 Hz), and with a flattening of the spectrum in the vicinity of this frequency. At small scales (above a few Hz), the spectra are steeper than -5/3 with values in the range of -2.1 to -2.8. These steeper slopes are consistent with expectations for kinetic Alfven turbulence, although their amplitude relative to the perpendicular fluctuations is larger than expected.

Mozer, F S

2013-01-01T23:59:59.000Z

466

Performance and scalability evaluation of the Ceph parallel file system  

Science Conference Proceedings (OSTI)

Ceph is an emerging open-source parallel distributed file and storage system. By design, Ceph leverages unreliable commodity storage and network hardware, and provides reliability and fault-tolerance via controlled object placement and data replication. ...

Feiyi Wang, Mark Nelson, Sarp Oral, Scott Atchley, Sage Weil, Bradley W. Settlemyer, Blake Caldwell, Jason Hill

2013-11-01T23:59:59.000Z

467

Parallel geometric-algebraic multigrid on unstructured forests of octrees  

Science Conference Proceedings (OSTI)

We present a parallel multigrid method for solving variable-coefficient elliptic partial differential equations on arbitrary geometries using highly adapted meshes. Our method is designed for meshes that are built from an unstructured hexahedral macro ...

Hari Sundar; George Biros; Carsten Burstedde; Johann Rudi; Omar Ghattas; Georg Stadler

2012-11-01T23:59:59.000Z

468

Parallel Fission Bank Algorithms in Monte Carlo Criticality Calculations  

E-Print Network (OSTI)

In this work we describe a new method for parallelizing the source iterations in a Monte Carlo criticality calculation. Instead of having one global fission bank that needs to be synchronized, as is traditionally done, our ...

Romano, Paul Kollath

469

Asynchronous parallel generating set search for linearly-constrained ...  

E-Print Network (OSTI)

cL ? cL ? AIr b ? b ? AEr. cU ? cU ? AIr. Ideally, the simple ...... chronous parallel pattern search for derivative-free optimization, ACM T. Math. Software.

470

Effective scheduling techniques for high-level parallel programming languages.  

E-Print Network (OSTI)

?? In the not-so-distant past, parallel programming was mostly the concern of programmers specializing in high-performance computing. Nowadays, on the other hand, many of today's… (more)

Rainey, Michael Alan

2010-01-01T23:59:59.000Z

471

Using linear congruential generators for parallel random number generation  

Science Conference Proceedings (OSTI)

Linear congruential random number generators are widely used in simulation and Monte Carlo calculations. Because they are very fast, and because they have minimal state space, they remain attractive for use in parallel computing environments. We discuss ...

M. J. Durst

1989-10-01T23:59:59.000Z

472

Normalized performance indices for message passing parallel programs  

Science Conference Proceedings (OSTI)

Existing tools for locating performance bottlenecks of message passing parallel programs either provide visualizations or profiles of program executions only; they do not highlight the cause of poor program performance. From the perspective ...

Sekhar R. Sarukkai; Jerry Yan; Jacob K. Gotwals

1994-07-01T23:59:59.000Z

473

A Comparison of Partitioning Schemes for Blockwise Parallel SAMR Algorithms  

Science Conference Proceedings (OSTI)

This paper presents an experimental comparison of dynamic partitioning techniques for blockwise parallel structured adaptive mesh refinement applications. A new partitioning technique, G-MISP, is described. Policies for the automatic selection of partitioner ...

Johan Steensland; Stefan Söderberg; Michael Thuné

2000-06-01T23:59:59.000Z

474

An Evaluation of Partitioners for Parallel SAMR Applications  

Science Conference Proceedings (OSTI)

This paper presents an experimental evaluation of a suite of dynamic partitioning/load-balancing techniques for adaptive grid hierarchies that underlie parallel structured adaptive mesh refinement applications. Partitioners evaluated include those included ...

Sumir Chandra; Manish Parashar

2001-08-01T23:59:59.000Z

475

Massive-scale RDF Processing Using Compressed Bitmap Indexes  

SciTech Connect

The Resource Description Framework (RDF) is a popular data model for representing linked data sets arising from the web, as well as large scienti#12;c data repositories such as UniProt. RDF data intrinsically represents a labeled and directed multi-graph. SPARQL is a query language for RDF that expresses subgraph pattern-#12;nding queries on this implicit multigraph in a SQL- like syntax. SPARQL queries generate complex intermediate join queries; to compute these joins e#14;ciently, we propose a new strategy based on bitmap indexes. We store the RDF data in column-oriented structures as compressed bitmaps along with two dictionaries. This paper makes three new contributions. (i) We present an e#14;cient parallel strategy for parsing the raw RDF data, building dictionaries of unique entities, and creating compressed bitmap indexes of the data. (ii) We utilize the constructed bitmap indexes to e#14;ciently answer SPARQL queries, simplifying the join evaluations. (iii) To quantify the performance impact of using bitmap indexes, we compare our approach to the state-of-the-art triple-store RDF-3X. We #12;nd that our bitmap index-based approach to answering queries is up to an order of magnitude faster for a variety of SPARQL queries, on gigascale RDF data sets.

Madduri, Kamesh; Wu, Kesheng

2011-05-26T23:59:59.000Z

476

WHAT ARE THE PROGENITORS OF COMPACT, MASSIVE, QUIESCENT GALAXIES AT z = 2.3? THE POPULATION OF MASSIVE GALAXIES AT z > 3 FROM NMBS AND CANDELS  

SciTech Connect

Using public data from the NEWFIRM Medium-Band Survey (NMBS) and the Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey (CANDELS), we investigate the population of massive galaxies at z > 3. The main aim of this work is to identify the potential progenitors of z {approx} 2 compact, massive, quiescent galaxies (CMQGs), furthering our understanding of the onset and evolution of massive galaxies. Our work is enabled by high-resolution images from CANDELS data and accurate photometric redshifts, stellar masses, and star formation rates (SFRs) from 37-band NMBS photometry. The total number of massive galaxies at z > 3 is consistent with the number of massive, quiescent galaxies (MQGs) at z {approx} 2, implying that the SFRs for all of these galaxies must be much lower by z {approx} 2. We discover four CMQGs at z > 3, pushing back the time for which such galaxies have been observed. However, the volume density for these galaxies is significantly less than that of galaxies at z < 2 with similar masses, SFRs, and sizes, implying that additional CMQGs must be created in the intervening {approx}1 Gyr between z = 3 and z = 2. We find five star-forming galaxies at z {approx} 3 that are compact (R{sub e} < 1.4 kpc) and have stellar mass M{sub *} > 10{sup 10.6} M{sub Sun }; these galaxies are likely to become members of the massive, quiescent, compact galaxy population at z {approx} 2. We evolve the stellar masses and SFRs of each individual z > 3 galaxy adopting five different star formation histories (SFHs) and studying the resulting population of massive galaxies at z = 2.3. We find that declining or truncated SFHs are necessary to match the observed number density of MQGs at z {approx} 2, whereas a constant delayed-exponential SFH would result in a number density significantly smaller than observed. All of our assumed SFHs imply number densities of CMQGs at z {approx} 2 that are consistent with the observed number density. Better agreement with the observed number density of CMQGs at z {approx} 2 is obtained if merging is included in the analysis and better still if star formation quenching is assumed to shortly follow the merging event, as implied by recent models of the formation of MQGs.

Stefanon, Mauro; Rudnick, Gregory H. [Department of Physics and Astronomy, University of Kansas, Malott Room 1082, 1251 Wescoe Hall Drive, Lawrence, KS 66045 (United States); Marchesini, Danilo [Physics and Astronomy Department, Tufts University, Robinson Hall, Room 257, Medford, MA 02155 (United States); Brammer, Gabriel B. [European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Vitacura, Santiago (Chile); Whitaker, Katherine E., E-mail: stefanonm@missouri.edu [Astrophysics Science Division, Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States)

2013-05-01T23:59:59.000Z

477

A memory mapping approach for network and controller optimization in parallel interleaver architectures  

Science Conference Proceedings (OSTI)

Recent communication standards and storage systems uses parallel architectures for error correcting codes (LDPC or Turbo-codes) to reliably transfer data between two equipments. However, parallel architectures suffer from memory access conflicts. In ... Keywords: interleavers, memory mapping, parallel architectures

Aroua Briki; Cyrille Chavet; Philippe Coussy

2013-05-01T23:59:59.000Z

478

High-level directives to drive the allocation of parallel object-oriented applications  

Science Conference Proceedings (OSTI)

The paper presents the Abstract Configuration Language (ACL) implemented within the Parallel Objects object oriented parallel programming environment. ACL defines a set of directives that allow users to specify the allocation needs of his/her application ... Keywords: ACL, ACL directives, Abstract Configuration Language, Parallel Objects object oriented parallel programming environment, allocation decisions, allocation needs, application components, high level directives, parallel languages, parallel object oriented application allocation, run time support, testbed application

A. Corradi; L. Leenardi; F. Zambonelli

1997-04-01T23:59:59.000Z

479

final report for Center for Programming Models for Scalable Parallel Computing  

SciTech Connect

This is the final report of the work on parallel programming patterns that was part of the Center for Programming Models for Scalable Parallel Computing

Johnson, Ralph E.

2013-04-10T23:59:59.000Z

480

Parallel I/O Software Infrastructure for Large-Scale Systems  

NLE Websites -- All DOE Office Websites (Extended Search)

Parallel IO Software Infrastructure for Large-Scale Systems Parallel IO Software Infrastructure for Large-Scale Systems | Tags: Math & Computer Science Choudhary.png An...

Note: This page contains sample records for the topic "massively parallel microcell-based" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


481

Massive black hole pairs in clumpy, self-gravitating circumnuclear disks: stochastic orbital decay  

E-Print Network (OSTI)

We study the dynamics of massive black hole pairs in clumpy gaseous circumnuclear disks. We track the orbital decay of the light, secondary black hole M_{\\bullet2} orbiting around the more massive primary at the center of the disk, using N-body/SPH simulations. We find that the gravitational interaction of M_{\\bullet2} with massive clumps M_cl erratically perturbs the otherwise smooth orbital decay. In close encounters with massive clumps, gravitational slingshots can kick the secondary black hole out of the disk plane. The black hole moving on an inclined orbit then experiences the weaker dynamical friction of the stellar background, resulting in a longer orbital decay timescale. Interactions between clumps can also favor orbital decay when the black hole is captured by a massive clump which is segregating toward the center of the disk. The stochastic behavior of the black hole orbit emerges mainly when the ratio M_{\\bullet2}/M_cl falls below unity, with decay timescales ranging from ~1 to ~50 Myr. This sugg...

Colpi, Monica

2013-01-01T23:59:59.000Z

482

Spectral energy distribution modelling of Southern candidate massive protostars using the Bayesian inference method  

E-Print Network (OSTI)

Concatenating data from the millimetre regime to the infrared, we have performed spectral energy distribution modelling for 227 of the 405 millimetre continuum sources of Hill et al. (2005) which are thought to contain young massive stars in the earliest stages of their formation. Three main parameters are extracted from the fits: temperature, mass and luminosity. The method employed was Bayesian inference, which allows a statistically probable range of suitable values for each parameter to be drawn for each individual protostellar candidate. This is the first application of this method to massive star formation. The cumulative distribution plots of the SED modelled parameters in this work indicate that collectively, the sources without methanol maser and/or radio continuum associations (MM-only cores) display similar characteristics to those of high mass star formation regions. Attributing significance to the marginal distinctions between the MM-only cores and the high-mass star formation sample we draw hypotheses regarding the nature of the MM-only cores, including the possibility that the population itself is comprised of different types of source, and discuss their role in the formation scenarios of massive star formation. In addition, we discuss the usefulness and limitations of SED modelling and its application to the field. From this work, it is clear that within the valid parameter ranges, SEDs utilising current far-infrared data can not be used to determine the evolution of massive protostars or massive young stellar objects.

T. Hill; C. Pinte; V. Minier; M. G. Burton; M. R. Cunningham

2008-10-17T23:59:59.000Z

483

Parallel heat transport in integrable and chaotic magnetic fields  

Science Conference Proceedings (OSTI)

The study of transport in magnetized plasmas is a problem of fundamental interest in controlled fusion, space plasmas, and astrophysics research. Three issues make this problem particularly challenging: (i) The extreme anisotropy between the parallel (i.e., along the magnetic field), {chi}{sub ||} , and the perpendicular, {chi}{sub Up-Tack }, conductivities ({chi}{sub ||} /{chi}{sub Up-Tack} may exceed 10{sup 10} in fusion plasmas); (ii) Nonlocal parallel transport in the limit of small collisionality; and (iii) Magnetic field lines chaos which in general complicates (and may preclude) the construction of magnetic field line coordinates. Motivated by these issues, we present a Lagrangian Green's function method to solve the local and non-local parallel transport equation applicable to integrable and chaotic magnetic fields in arbitrary geometry. The method avoids by construction the numerical pollution issues of grid-based algorithms. The potential of the approach is demonstrated with nontrivial applications to integrable (magnetic island), weakly chaotic (Devil's staircase), and fully chaotic magnetic field configurations. For the latter, numerical solutions of the parallel heat transport equation show that the effective radial transport, with local and non-local parallel closures, is non-diffusive, thus casting doubts on the applicability of quasilinear diffusion descriptions. General conditions for the existence of non-diffusive, multivalued flux-gradient relations in the temperature evolution are derived.

Castillo-Negrete, D. del; Chacon, L. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-8071 (United States)

2012-05-15T23:59:59.000Z

484

SAMPEG, a Scene Adaptive Parallel MPEG-2 Software Encoder  

E-Print Network (OSTI)

This paper presents a fully software-based MPEG-2 encoder architecture, which uses scene-change detection to optimize the Group-of-Picture (GOP) structure for the actual video sequence. This feature enables easy, lossless edit cuts at scene-change positions and it also improves overall picture quality by providing good reference frames for motion prediction. Another favourable aspect is the high coding speed obtained, because the encoder is based on a novel concept for parallel MPEG coding on SMP machines. This concept allows the use of advanced frame-based coding algorithms for motion estimation and adaptive quantization, thereby enabling high-quality software encoding in real-time. Our proposal can be combined with the conventional parallel computing approach on slice basis, to further improve parallelization eciency. The concepts in the current SAMPEG implementation for MPEG-2 are directly applicable to MPEG-4 encoders.

Dirk Farin; Niels Mache; Peter H. N. de With; Peter H. N. De

2001-01-01T23:59:59.000Z

485

A new parallel sorting approach with sorting memory module  

Science Conference Proceedings (OSTI)

A new approach to accelerating parallel sorting processes is introduced in this paper. This approach involves the design of a new type of memory chip with sorting functions. This type of sorting memory chip is feasible with today's VLSI techniques. A memory module organizing several sorting memory chips associated with additional ECL or TTL control logic circuits is also presented. Using the sorting memory modules in a shared memory parallel processor machine, parallel sorting algorithms such as the column sort method can reduce the row access time significantly and avoid data collisions in the interconnection network. Experimental simulation results on the practical speedup achieved and the memory utilization for the proposed approach are described.

Zhu, C.Q. (Illinois Univ., Urbana, IL (USA). Center for Supercomputing Research and Development); Fang, Z. (Research and Development, Concurrent Computer Corp., Tinton Falls, NJ (US)); Li, X. (Dept. of Computing Science, Univ. of Alberta, Edmonton, Alberta (CA))

1989-12-01T23:59:59.000Z

486

Automatic Parallel Parking and Returning to Traffic Maneuvers  

E-Print Network (OSTI)

This video illustrates a control approach developed to perform parallel parking and returning to traffic maneuvers for a car capable of autonomous motion. The key idea is to carry out a motion control procedure involving a "Localization-Planning-Execution" cycle until a specified location of the car relative to its environment is reached. Range measurements are used to model environmental objects around the car. The automatic maneuvers developed are demonstrated on an experimental electric autonomous car in a usual traffic environment. 1 Introduction Many drivers have difficulties or make errors while parallel parking or in pulling out of a parking place. A control approach to automatic parallel parking and pulling out maneuvers has been developed and tested on an experimental electric car capable of autonomous motion. The manual car driving is supplemented with an automatic steering and velocity control [1]. The car is equiped with: (1) - a sensor unit to measure relative distances ...

Igor Paromtchik; Christian Laugier

1998-01-01T23:59:59.000Z

487

Plasil: Heuristic Reduction of Parallelism in Component Environment  

E-Print Network (OSTI)

Abstract. Code model checking of software components suffers from the well-known problem of state explosion when applied to highly parallel components, despite the fact that a single component typically comprises a smaller state space than the whole system. We present a technique that addresses the problem of state explosion in code checking of primitive components with the Java PathFinder in case the checked property is absence of concurrency errors. The key idea is reduction of parallelism in the environment so that only those parts of the component’s code that can likely cause concurrency errors are exercised in parallel; such parts are identified via a heuristic static code analysis (searching for “suspicious ” patterns in the component code). Benefits of the technique, i.e. support for discovery of concurrency errors in limited time and space and provision of easy-to-read counterexamples, are illustrated on the results of several experiments.

Pavel Parizek; Frantisek Plasil

2007-01-01T23:59:59.000Z

488

PARALLEL ION BEAM PROFILE SCAN USING LASER WIRE  

Science Conference Proceedings (OSTI)

We report on the world s first experiment of a parallel profile scan of the hydrogen ion (H-) beam using a laser wire system. The system was developed at the superconducting linac of the Spallation Neutron Source (SNS) accelerator complex. The laser wire profile scanner is based on a photo-detachment process and therefore can be conducted on an operational H- beam in a nonintrusive manner. The parallel profile scanning system makes it possible to simultaneously measure profiles of the 1-MW neutron production H- beam at 9 different locations of the linac by using a single light source. This paper describes the design, optical system and software platform development, and measurement results of the parallel profile scanning system.

Liu, Yun [ORNL; Aleksandrov, Alexander V [ORNL; Huang, Chunning [ORNL; Long, Cary D [ORNL; Dickson, Richard W [ORNL

2013-01-01T23:59:59.000Z

489

Parallel Scaling Characteristics of Selected NERSC User ProjectCodes  

Science Conference Proceedings (OSTI)

This report documents parallel scaling characteristics of NERSC user project codes between Fiscal Year 2003 and the first half of Fiscal Year 2004 (Oct 2002-March 2004). The codes analyzed cover 60% of all the CPU hours delivered during that time frame on seaborg, a 6080 CPU IBM SP and the largest parallel computer at NERSC. The scale in terms of concurrency and problem size of the workload is analyzed. Drawing on batch queue logs, performance data and feedback from researchers we detail the motivations, benefits, and challenges of implementing highly parallel scientific codes on current NERSC High Performance Computing systems. An evaluation and outlook of the NERSC workload for Allocation Year 2005 is presented.

Skinner, David; Verdier, Francesca; Anand, Harsh; Carter,Jonathan; Durst, Mark;