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Note: This page contains sample records for the topic "dynamic optimization model" 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.


1

A dynamic system model of biogeography-based optimization  

Science Conference Proceedings (OSTI)

Abstract: We derive a dynamic system model for biogeography-based optimization (BBO) that is asymptotically exact as the population size approaches infinity. The states of the dynamic system are equal to the proportion of each individual in the population; ... Keywords: Biogeography-based optimization, Dynamic system, Evolutionary algorithm, Genetic algorithm, Global uniform recombination, Markov model

Dan Simon

2011-12-01T23:59:59.000Z

2

Optimal foreign borrowing in a multisector dynamic equilibrium model for Brazil  

E-Print Network (OSTI)

This paper shows how a dynamic multisector equilibrium model can be formulated to be able to analyze the optimal borrowing policy of a developing country. It also describes how a non-linear programming model with the ...

Tourinho, Octv?io A. F.

1985-01-01T23:59:59.000Z

3

Dynamic Policy Modeling for Chronic Diseases: Metaheuristic-Based Identification of Pareto-Optimal Screening Strategies  

Science Conference Proceedings (OSTI)

We present a risk-group oriented chronic disease progression model embedded within a metaheuristic-based optimization of the policy variables. Policy-makers are provided with Pareto-optimal screening schedules for risk groups by considering cost and ... Keywords: chronic disease policy analysis, decision analysis, dynamic resource allocation, health care, metaheuristics, multicriteria optimization, prevention

Marion S. Rauner; Walter J. Gutjahr; Kurt Heidenberger; Joachim Wagner; Joseph Pasia

2010-09-01T23:59:59.000Z

4

Data-driven dynamic emulation modelling for the optimal management of environmental systems  

Science Conference Proceedings (OSTI)

The optimal management of large environmental systems is often limited by the high computational burden associated to the process-based models commonly adopted to describe such systems. In this paper we propose a novel data-driven Dynamic Emulation Modelling ... Keywords: Data-driven models, Emulation modelling, Process-based models, Variable selection, Water resources planning and management

A. Castelletti; S. Galelli; M. Restelli; R. Soncini-Sessa

2012-06-01T23:59:59.000Z

5

Developing a computationally efficient dynamic multilevel hybrid optimization scheme using multifidelity model interactions.  

SciTech Connect

Many engineering application problems use optimization algorithms in conjunction with numerical simulators to search for solutions. The formulation of relevant objective functions and constraints dictate possible optimization algorithms. Often, a gradient based approach is not possible since objective functions and constraints can be nonlinear, nonconvex, non-differentiable, or even discontinuous and the simulations involved can be computationally expensive. Moreover, computational efficiency and accuracy are desirable and also influence the choice of solution method. With the advent and increasing availability of massively parallel computers, computational speed has increased tremendously. Unfortunately, the numerical and model complexities of many problems still demand significant computational resources. Moreover, in optimization, these expenses can be a limiting factor since obtaining solutions often requires the completion of numerous computationally intensive simulations. Therefore, we propose a multifidelity optimization algorithm (MFO) designed to improve the computational efficiency of an optimization method for a wide range of applications. In developing the MFO algorithm, we take advantage of the interactions between multi fidelity models to develop a dynamic and computational time saving optimization algorithm. First, a direct search method is applied to the high fidelity model over a reduced design space. In conjunction with this search, a specialized oracle is employed to map the design space of this high fidelity model to that of a computationally cheaper low fidelity model using space mapping techniques. Then, in the low fidelity space, an optimum is obtained using gradient or non-gradient based optimization, and it is mapped back to the high fidelity space. In this paper, we describe the theory and implementation details of our MFO algorithm. We also demonstrate our MFO method on some example problems and on two applications: earth penetrators and groundwater remediation.

Hough, Patricia Diane (Sandia National Laboratories, Livermore, CA); Gray, Genetha Anne (Sandia National Laboratories, Livermore, CA); Castro, Joseph Pete Jr. (; .); Giunta, Anthony Andrew

2006-01-01T23:59:59.000Z

6

Modeling and optimization of an adaptive dynamic load shedding using the ANFIS-PSO algorithm  

Science Conference Proceedings (OSTI)

This paper presents a new optimal adaptive dynamic load-shedding scheme for a large steelmaking industry with cogeneration units. The proposed method is based on the initial rate of a frequency change (df0/dt) and is coordinated with tie-lines frequency ... Keywords: adaptive network-based fuzzy inference system, artificial neural network, frequency stability, optimal load shedding, particle swarm optimization, under-frequency relays

Ghader Isazadeh; Rahmat-Allah Hooshmand; Amin Khodabakhshian

2012-02-01T23:59:59.000Z

7

Optimal control of nonlinear dynamic econometric models: An algorithm and an application  

Science Conference Proceedings (OSTI)

OPTCON is an algorithm for the optimal control of nonlinear stochastic systems which is particularly applicable to econometric models. It delivers approximate numerical solutions to optimum control problems with a quadratic objective function for nonlinear ... Keywords: Algorithms, Econometric modeling, Optimal control, Policy applications, Stochastic control

V. Blueschke-Nikolaeva; D. Blueschke; R. Neck

2012-11-01T23:59:59.000Z

8

Evolutionary Approaches for Strain Optimization Using Dynamic Models under a Metabolic Engineering Perspective  

Science Conference Proceedings (OSTI)

One of the purposes of Systems Biology is the quantitative modeling of biochemical networks. In this effort, the use of dynamical mathematical models provides for powerful tools in the prediction of the phenotypical behavior of microorganisms under distinct ...

Pedro Evangelista; Isabel Rocha; Eugénio C. Ferreira; Miguel Rocha

2009-04-01T23:59:59.000Z

9

A dynamic model for optimally phasing in CO2 capture and storage infrastructure  

Science Conference Proceedings (OSTI)

CO"2 capture and storage (CCS) is a climate-change mitigation strategy that requires an investment of many billions of dollars and tens of thousands of miles of dedicated CO"2 pipelines. To be effective, scientists, stakeholders, and policy makers will ... Keywords: CO2 capture and storage, Climate-change policy, Infrastructure modeling, Pipeline modeling, SimCCS, Spatiotemporal optimization

Richard S. Middleton; Michael J. Kuby; Ran Wei; Gordon N. Keating; Rajesh J. Pawar

2012-11-01T23:59:59.000Z

10

Predicting locality phases for dynamic memory optimization  

Science Conference Proceedings (OSTI)

Dynamic data, cache, and memory adaptation can significantly improve program performance when they are applied on long continuous phases of execution that have dynamic but predictable locality. To support phase-based adaptation, this paper defines the ... Keywords: Dynamic optimization, Locality analysis and optimization, Phase hierarchy, Program phase prediction, Reconfigurable architecture

Xipeng Shen; Yutao Zhong; Chen Ding

2007-07-01T23:59:59.000Z

11

Dynamic clustering using combinatorial particle swarm optimization  

Science Conference Proceedings (OSTI)

Combinatorial Particle Swarm Optimization (CPSO) is a relatively recent technique for solving combinatorial optimization problems. CPSO has been used in different applications, e.g., partitional clustering and project scheduling problems, and it has ... Keywords: Combinatorial optimization problems, Combinatorial particle swarm optimization, Dynamic clustering, Partitional clustering

Hamid Masoud; Saeed Jalili; Seyed Mohammad Hasheminejad

2013-04-01T23:59:59.000Z

12

Optimization Online - Python Optimization Modeling Objects (Pyomo)  

E-Print Network (OSTI)

Sep 24, 2008 ... sandia.gov). Abstract: We describe Pyomo, an open-source tool for modeling optimization applications in Python. Pyomo can be used to define ...

13

Optimization Online - Python Optimization Modeling Objects (Pyomo)  

E-Print Network (OSTI)

Dec 30, 2009 ... Python Optimization Modeling Objects (Pyomo). William Hart(wehart ***at*** sandia.gov) Jean-Paul Watson(jwatson ***at*** sandia.gov)

14

Application of optimal prediction to molecular dynamics  

SciTech Connect

Optimal prediction is a general system reduction technique for large sets of differential equations. In this method, which was devised by Chorin, Hald, Kast, Kupferman, and Levy, a projection operator formalism is used to construct a smaller system of equations governing the dynamics of a subset of the original degrees of freedom. This reduced system consists of an effective Hamiltonian dynamics, augmented by an integral memory term and a random noise term. Molecular dynamics is a method for simulating large systems of interacting fluid particles. In this thesis, I construct a formalism for applying optimal prediction to molecular dynamics, producing reduced systems from which the properties of the original system can be recovered. These reduced systems require significantly less computational time than the original system. I initially consider first-order optimal prediction, in which the memory and noise terms are neglected. I construct a pair approximation to the renormalized potential, and ignore three-particle and higher interactions. This produces a reduced system that correctly reproduces static properties of the original system, such as energy and pressure, at low-to-moderate densities. However, it fails to capture dynamical quantities, such as autocorrelation functions. I next derive a short-memory approximation, in which the memory term is represented as a linear frictional force with configuration-dependent coefficients. This allows the use of a Fokker-Planck equation to show that, in this regime, the noise is {delta}-correlated in time. This linear friction model reproduces not only the static properties of the original system, but also the autocorrelation functions of dynamical variables.

Barber IV, John Letherman

2004-12-01T23:59:59.000Z

15

Optimal control of leukemic cell population dynamics  

E-Print Network (OSTI)

Sep 5, 2013 ... This issue can be formulated as an optimal control problem. The dynamics of leukemic cell populations in culture is given by age-structured ...

16

Optimization Online - Optimizing Preventive Maintenance Models  

E-Print Network (OSTI)

Jun 29, 2004 ... Optimizing Preventive Maintenance Models ... It is assumed that there is a known model which predicts the frequency of system failure as a function of ... Category 2: Applications -- OR and Management Sciences (Scheduling ).

17

HOMER® Micropower Optimization Model  

DOE Green Energy (OSTI)

NREL has developed the HOMER micropower optimization model. The model can analyze all of the available small power technologies individually and in hybrid configurations to identify least-cost solutions to energy requirements. This capability is valuable to a diverse set of energy professionals and applications. NREL has actively supported its growing user base and developed training programs around the model. These activities are helping to grow the global market for solar technologies.

Lilienthal, P.

2005-01-01T23:59:59.000Z

18

A new modeling approach of STLF with integrated dynamics mechanism and based on the fusion of dynamic optimal neighbor phase points and ICNN  

Science Conference Proceedings (OSTI)

Based on the time evolution similarity principle of the topological neighbor phase points in the Phase Space Reconstruction (PSR), a new modeling approach of Short-Term Load Forecasting (STLF) with integrated dynamics mechanism and based on the fusion ...

Zhisheng Zhang; Yaming Sun; Shiying Zhang

2006-05-01T23:59:59.000Z

19

TRACKING CODE DEVELOPMENT FOR BEAM DYNAMICS OPTIMIZATION  

SciTech Connect

Dynamic aperture (DA) optimization with direct particle tracking is a straight forward approach when the computing power is permitted. It can have various realistic errors included and is more close than theoretical estimations. In this approach, a fast and parallel tracking code could be very helpful. In this presentation, we describe an implementation of storage ring particle tracking code TESLA for beam dynamics optimization. It supports MPI based parallel computing and is robust as DA calculation engine. This code has been used in the NSLS-II dynamics optimizations and obtained promising performance.

Yang, L.

2011-03-28T23:59:59.000Z

20

Project: Sustainability Modeling and Optimization  

Science Conference Proceedings (OSTI)

... and the capabilities to formulate simulation and optimization models. ... “Energy Efficiency Analysis for a Casting Production System,” Berglund ...

2012-12-27T23:59:59.000Z

Note: This page contains sample records for the topic "dynamic optimization model" 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

Dynamic Scheduling via Polymatroid Optimization  

Science Conference Proceedings (OSTI)

Dynamic scheduling of multi-class jobs in queueing systems has wide ranging applications, but in general is a very difficult control problem. Here we focus on a class of systems for which conservation laws hold. Consequently, the performance space becomes ...

David D. Yao

2002-01-01T23:59:59.000Z

22

Metadata driven memory optimizations in dynamic binary translator  

Science Conference Proceedings (OSTI)

A dynamic binary translator offers solutions for translating and running source architecture binaries on target architecture at runtime. Regardless of its growing popularity, practical dynamic binary translators usually suffer from the limited optimizations ... Keywords: dynamic binary translator, memory optimizations, metadata

Chaohao Xu; Jianhui Li; Tao Bao; Yun Wang; Bo Huang

2007-06-01T23:59:59.000Z

23

Optimized Constant Pressure Stochastic Dynamics  

E-Print Network (OSTI)

A recently proposed method for computer simulations in the isothermal-isobaric (NPT) ensemble, based on Langevin-type equations of motion for the particle coordinates and the ``piston'' degree of freedom, is re-derived by straightforward application of the standard Kramers-Moyal formalism. An integration scheme is developed which reduces to a time-reversible symplectic integrator in the limit of vanishing friction. This algorithm is hence expected to be quite stable for small friction, allowing for a large time step. We discuss the optimal choice of parameters, and present some numerical test results.

A. Kolb; B. Duenweg

1999-03-29T23:59:59.000Z

24

Optimized constant pressure stochastic dynamics  

E-Print Network (OSTI)

A recently proposed method for computer simulations in the isothermal– isobaric (NPT) ensemble, based on Langevin–type equations of motion for the particle coordinates and the “piston ” degree of freedom, is re–derived by straightforward application of the standard Kramers–Moyal formalism. An integration scheme is developed which reduces to a time–reversible symplectic integrator in the limit of vanishing friction. This algorithm is hence expected to be quite stable for small friction, allowing for a large time step. We discuss the optimal choice of parameters, and present some numerical test results.

A. Kolb; B. Dünweg

1999-01-01T23:59:59.000Z

25

Structural dynamics test simulation and optimization for aerospace components  

SciTech Connect

This paper initially describes an innovative approach to product realization called Knowledge Based Testing (KBT). This research program integrates test simulation and optimization software, rapid fabrication techniques and computational model validation to support a new experimentally-based design concept. This design concept implements well defined tests earlier in the design cycle enabling the realization of highly reliable aerospace components. A test simulation and optimization software environment provides engineers with an essential tool needed to support this KBT approach. This software environment, called the Virtual Environment for Test Optimization (VETO), integrates analysis and test based models to support optimal structural dynamic test design. A goal in developing this software tool is to provide test and analysis engineers with a capability of mathematically simulating the complete structural dynamics test environment within a computer. A developed computational model of an aerospace component can be combined with analytical and/or experimentally derived models of typical structural dynamic test instrumentation within the VETO to determine an optimal test design. The VETO provides the user with a unique analysis and visualization environment to evaluate new and existing test methods in addition to simulating specific experiments designed to maximize test based information needed to validate computational models. The results of both a modal and a vibration test design are presented for a reentry vehicle and a space truss structure.

Klenke, S.E.; Baca, T.J.

1996-06-01T23:59:59.000Z

26

AVESTAR® - Dynamic Modeling  

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

Dynamic Modeling Dynamic Modeling The AVESTAR team is pursuing research on the dynamic modeling and simulation of advanced energy systems ranging from power plants to power grids. Dynamic models provide a continuous view of energy systems in action by calculating their transient behavior over time. Plant-wide Models For power plants, dynamic models are used to analyze a wide variety of operating scenarios, including normal base load operation, startup, shutdown, feedstock switchovers, cycling, and load-following. Dynamic process and control models are also essential for analyzing plant responses to setpoint changes and disturbances, as well as malfunctions and abnormal situations. Other applications of plant-wide dynamic models include controllability and operational flexibility analyses, environmental studies, safety evaluations, and risk mitigation.

27

Model test optimization using the virtual environment for test optimization  

SciTech Connect

We present a software environment integrating analysis and test-based models to support optimal modal test design through a Virtual Environment for Test Optimization (VETO). The VETO assists analysis and test engineers to maximize the value of each modal test. It is particularly advantageous for structural dynamics model reconciliation applications. The VETO enables an engineer to interact with a finite element model of a test object to optimally place sensors and exciters and to investigate the selection of data acquisition parameters needed to conduct a complete modal survey. Additionally, the user can evaluate the use of different types of instrumentation such as filters, amplifiers and transducers for which models are available in the VETO. The dynamic response of most of the virtual instruments (including the device under test) are modeled in the state space domain. Design of modal excitation levels and appropriate test instrumentation are facilitated by the VETO`s ability to simulate such features as unmeasured external inputs, A/D quantization effects, and electronic noise. Measures of the quality of the experimental design, including the Modal Assurance Criterion, and the Normal Mode Indicator Function are available. The VETO also integrates tools such as Effective Independence and minamac to assist in selection of optimal sensor locations. The software is designed about three distinct modules: (1) a main controller and GUI written in C++, (2) a visualization model, taken from FEAVR, running under AVS, and (3) a state space model and time integration module built in SIMULINK. These modules are designed to run as separate processes on interconnected machines.

Klenke, S.E.; Reese, G.M.; Schoof, L.A.; Shierling, C.

1995-11-01T23:59:59.000Z

28

Development of a Laboratory Verified Single-Duct VAV System Model with Fan Powered Terminal Units Optimized Using Computational Fluid Dynamics  

E-Print Network (OSTI)

Single Duct Variable Air Volume (SDVAV) systems use series and parallel Fan Powered Terminal Units to control the air flow in conditioned spaces. This research developed a laboratory verified model of SDVAV systems that used series and parallel fan terminal units where the fan speeds were controlled by either Silicon Controlled Rectifiers (SCR) or Electronically Commutated Motors (ECM) motors. As part of the research, the model was used to compare the performance of the systems and to predict the harmonics generated by ECM systems. All research objectives were achieved. The CFD model, which was verified with laboratory measurements, showed the potential to identify opportunities for improvement in the design of the FPTU and accurately predicted the static pressure drop as air passed through the unit over the full operating range of the FPTU. Computational fluid dynamics (CFD) models of typical a FPTU were developed and used to investigate opportunities for optimizing the design of FPTUs. The CFD model identified key parameters required to conduct numerical simulations of FPTU and some of the internal components used to manufacture the units. One key internal component was a porous baffle used to enhance mixing when primary air and induced air entered the mixing chamber. The CFD analysis showed that a pressure-drop based on face velocity model could be used to accurately predict the performance of the FPTU. The SDVAV simulation results showed that parallel FPTUs used less energy overall than series systems that used SCR motors as long as primary air leakage was not considered. Simulation results also showed that series ECM FPTUs used about the same amount of energy, within 3 percent, of parallel FPTU even when leakage was not considered. A leakage rate of 10 percent was enough to reduce the performance of the parallel FPTU to the level of the series SCR system and the series ECM FPTUs outperformed the parallel FPTUs at all weather locations used in the study.

Davis, Michael A.

2010-08-01T23:59:59.000Z

29

Dynamic Simulation and Optimization of Nuclear Hydrogen Production Systems  

DOE Green Energy (OSTI)

This project is part of a research effort to design a hydrogen plant and its interface with a nuclear reactor. This project developed a dynamic modeling, simulation and optimization environment for nuclear hydrogen production systems. A hybrid discrete/continuous model captures both the continuous dynamics of the nuclear plant, the hydrogen plant, and their interface, along with discrete events such as major upsets. This hybrid model makes us of accurate thermodynamic sub-models for the description of phase and reaction equilibria in the thermochemical reactor. Use of the detailed thermodynamic models will allow researchers to examine the process in detail and have confidence in the accurary of the property package they use.

Paul I. Barton; Mujid S. Kaximi; Georgios Bollas; Patricio Ramirez Munoz

2009-07-31T23:59:59.000Z

30

The optimization of the stocks within coal power stations using the dynamic programming method  

Science Conference Proceedings (OSTI)

The purpose of this paper is to devise an economic and mathematical model for forecasting and optimizing the need of coal, for determining the current stock size and optimizing the supply-storage costs within a coal-fired power plant. The conditions ... Keywords: continuous flow production, dynamic programming method, energetic resources, optimization of the safety stock, power plants, stock analysis

Rascolean Ilie; Isac Claudia; Dura Codruta

2009-12-01T23:59:59.000Z

31

Efficient optimal design of uncertain discrete time dynamical systems  

Science Conference Proceedings (OSTI)

In this paper we consider the problem of optimal design of an uncertain discrete time nonlinear dynamical system. The problem is formulated using an a-posterori design criterion, which can account for uncertainties generated by the dynamics of the system ... Keywords: Discrete time dynamical systems, Optimal design, Randomized algorithms, Uncertain parameters

Chenxi Lin; Thordur Runolfsson

2012-10-01T23:59:59.000Z

32

The DynCOAA algorithm for dynamic constraint optimization problems  

Science Conference Proceedings (OSTI)

Numerous problems in software coordination, operations research, manufacturing control and others can be transformed in constraint optimization problems (COPs). Moreover, most practical problems change constantly, requiring algorithms that can handle ... Keywords: ACO, distributed constraint optimization, dynamic

Koenraad Mertens; Tom Holvoet; Yolande Berbers

2006-05-01T23:59:59.000Z

33

Code Reordering and Speculation Support for Dynamic Optimization System  

Science Conference Proceedings (OSTI)

Abstract: For dynamic optimization systems, success is limited by two difficult problems arising from instruction reordering. Following optimization within and across basic block boundaries, both the ordering of exceptions and the observed processor ...

Erik M. Nystrom; Ronald D. Barnes; Matthew C. Merten; Wen-mei W. Hwu

2001-09-01T23:59:59.000Z

34

Nonsmooth dynamic optimization of systems with varying structure  

E-Print Network (OSTI)

In this thesis, an open-loop numerical dynamic optimization method for a class of dynamic systems is developed. The structure of the governing equations of the systems under consideration change depending on the values of ...

Yunt, Mehmet, 1975-

2011-01-01T23:59:59.000Z

35

Dynamic optimization with a new performance index for a 2-dof translational parallel manipulator  

Science Conference Proceedings (OSTI)

The dynamic analysis and optimization problem of a 2-DoF Translational Parallel Manipulator (TPM) is addressed in this paper. Based on the principle of virtual work and the concept of link Jacobian matrix, the explicit expressions of the dynamic model ... Keywords: global and comprehensive dynamic performance index (GCDPI), hardware in the loop simulation (HILS), operational space formulation, translational parallel manipulator

Gang Zhang; PinKuan Liu; Han Ding

2012-10-01T23:59:59.000Z

36

Dynamic Optimization of Lean Burn Engine Aftertreatment  

E-Print Network (OSTI)

The competition to deliver fuel e#cient and environmentally friendly vehicles is driving the 1 2 Submitted to Journal of Dynamics Systems, Measurement, & Control automotive industry to consider ever more complex powertrain systems. Adequate performance of these new highly interactive systems can no longer be obtained through traditional approaches, which are intensive in hardware use and #nal control software calibration. This paper explores the use of Dynamic Programming to make model-based design decisions for a lean burn, direct injection spark ignition engine, in combination with a three way catalyst and an additional threeway catalyst, often referred to as a lean NOx trap. The primary contribution is the development ofavery rapid method to evaluate the tradeo#s in fuel economy and emissions for this novel powertrain system, as a function of design parameters and controller structure, over a standard emission test cycle. 1 Introduction Designing a powertrain system to m...

Jun-Mo Kang; Ilya Kolmanovsky; J. W. Grizzle

2001-01-01T23:59:59.000Z

37

Dynamic Multidrug Therapies for HIV: Optimal and STI Control Approaches  

E-Print Network (OSTI)

Dynamic Multidrug Therapies for HIV: Optimal and STI Control Approaches B. M. Adams 1, H. T. Banks and analyzing an optimal control problem using two types of dynamic treatments representing reverse of immune-mediated control of HIV. Our numerical results support a scenario in which STI therapies can lead

38

HOMER: The Micropower Optimization Model  

Science Conference Proceedings (OSTI)

HOMER, the micropower optimization model, helps users to design micropower systems for off-grid and grid-connected power applications. HOMER models micropower systems with one or more power sources including wind turbines, photovoltaics, biomass power, hydropower, cogeneration, diesel engines, cogeneration, batteries, fuel cells, and electrolyzers. Users can explore a range of design questions such as which technologies are most effective, what size should components be, how project economics are affected by changes in loads or costs, and is the renewable resource adequate.

Not Available

2004-03-01T23:59:59.000Z

39

Biotrans: Cost Optimization Model | Open Energy Information  

Open Energy Info (EERE)

Biotrans: Cost Optimization Model Biotrans: Cost Optimization Model Jump to: navigation, search Tool Summary LAUNCH TOOL Name: Biotrans: Cost Optimization Model Focus Area: Ethanol Topics: Market Analysis Website: www.ecn.nl/units/ps/models-and-tools/biotrans/ Equivalent URI: cleanenergysolutions.org/content/biotrans-cost-optimization-model,http Language: English Policies: Deployment Programs DeploymentPrograms: Demonstration & Implementation BIOTRANS optimizes the biofuel supply chain allocation by finding the least-cost configuration of resources and trade to meet a specified biofuel demand in the European transportation sector. The user can constrain the optimization by inputting a number of economic and technological assumptions for a specific target year. References Retrieved from

40

Optimization models for ATM network planning  

Science Conference Proceedings (OSTI)

This article describes mathematical programming models that have been developed and employed to evaluate configuration strategies for metropolitan ATM telecommunication networks. The models determine the optimal placement of ATM switch hardware and fiber ... Keywords: ATM, network optimization, telecommunications

Dennis C. Dietz; Amie J. Elcan; Daphne E. Skipper

2003-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamic optimization model" 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

A single front genetic algorithm for parallel multi-objective optimization in dynamic environments  

Science Conference Proceedings (OSTI)

This paper proposes a new parallel evolutionary procedure to solve multi-objective dynamic optimization problems along with some measures to evaluate multi-objective optimization in dynamic environments. These dynamic optimization problems appear in ... Keywords: Dynamic optimization problems, Neuro-dynamic programming, Parallel evolutionary algorithms, Parallel multi-objective optimization

Mario Cámara; Julio Ortega; Francisco de Toro

2009-10-01T23:59:59.000Z

42

Numerical Modeling and Optimization of Microstructure Evolution ...  

Science Conference Proceedings (OSTI)

Presentation Title, Numerical Modeling and Optimization of Microstructure Evolution ... A Hybrid Model on Low Energy Ion Beam Processing Leading to Phase ...

43

Dynamic archive evolution strategy for multiobjective optimization  

Science Conference Proceedings (OSTI)

This paper proposes a new multiobjective evolutionary approach—the dynamic archive evolution strategy (DAES) to investigate the adaptive balance between proximity and diversity. In DAES, a novel dynamic external archive is proposed to store elitist ...

Yang Shu Min; Shao Dong Guo; Luo Yang Jie

2005-03-01T23:59:59.000Z

44

Optimization of naïve dynamic binary instrumentation Tools/  

E-Print Network (OSTI)

The proliferation of dynamic program analysis tools has done much to ease the burden of developing complex software. However, creating such tools remains a challenge. Dynamic binary instrumentation frameworks such as ...

Kleckner, Reid (Reid N.)

2011-01-01T23:59:59.000Z

45

Constructing optimal designs for fitting pharmacokinetic models  

Science Conference Proceedings (OSTI)

We consider some computational issues that arise when searching for optimal designs for pharmacokinetic (PK) studies. Special factors that distinguish these are (i) repeated observations are taken from each subject and the observations are usually described ... Keywords: Bayesian optimal design, D-optimality, general optimisation, nonlinear mixed model, pharmacokinetic model

B. Jones; J. Wang

1999-07-01T23:59:59.000Z

46

Modeling and optimization of permanent magnetic motors  

E-Print Network (OSTI)

This thesis develops analytic models for the prediction and optimization of radial-flux permanent magnet motor torque and efficiency. It also facilitates the design optimization of electromagnetically-powered rotorcraft ...

Pinkham, Andrew P

2008-01-01T23:59:59.000Z

47

Dynamic optimization of fractionation schedules in radiation therapy  

E-Print Network (OSTI)

In this thesis, we investigate the improvement in treatment effectiveness when dynamically optimizing the fractionation scheme in radiation therapy. In the first part of the thesis, we consider delivering a different dose ...

Ramakrishnan, Jagdish

2013-01-01T23:59:59.000Z

48

Generating optimal plans in highly-dynamic domains  

Science Conference Proceedings (OSTI)

Generating optimal plans in highly dynamic environments is challenging. Plans are predicated on an assumed initial state, but this state can change unexpectedly during plan generation, potentially invalidating the planning effort. In this paper we make ...

Christian Fritz; Sheila A. McIlraith

2009-06-01T23:59:59.000Z

49

Noise-optimal capture for high dynamic range photography  

E-Print Network (OSTI)

Taking multiple exposures is a well-established approach both for capturing high dynamic range (HDR) scenes and for noise reduction. But what is the optimal set of photos to capture? The typical approach to HDR capture ...

Hasinoff, Samuel William

50

From link dynamics to path lifetime and packet-length optimization in MANETs  

Science Conference Proceedings (OSTI)

We present an analytical framework and statistical models to accurately characterize the lifetime of a wireless link and multi-hop paths in mobile ad hoc networks (MANET). We show that the lifetimes of links and paths can be computed through a two-state ... Keywords: Analytical mobility modeling, Link dynamics, Markov model, Optimal information segmentation, Path lifetime

Xianren Wu; Hamid R. Sadjadpour; J. J. Garcia-Luna-Aceves

2009-07-01T23:59:59.000Z

51

An optimization approach to kinetic model reduction for combustion chemistry  

E-Print Network (OSTI)

Model reduction methods are relevant when the computation time of a full convection-diffusion-reaction simulation based on detailed chemical reaction mechanisms is too large. In this article, we review a model reduction approach based on optimization of trajectories and show its applicability to realistic combustion models. As most model reduction methods, it identifies points on a slow invariant manifold based on time scale separation in the dynamics of the reaction system. The numerical approximation of points on the manifold is achieved by solving a semi-infinite optimization problem, where the dynamics enter the problem as constraints. The proof of existence of a solution for an arbitrarily chosen dimension of the reduced model (slow manifold) is extended to the case of realistic combustion models including thermochemistry by considering the properties of proper maps. The model reduction approach is finally applied to three models based on realistic reaction mechanisms: 1. ozone decomposition as a small t...

Lebiedz, Dirk

2013-01-01T23:59:59.000Z

52

An Infrastructure for Adaptive Dynamic Optimization  

E-Print Network (OSTI)

and can be used for instru- mentation, profiling, dynamic translation, etc. To demonstrate the usefulnessRIO performance is 12%. 1 Introduction The power and reach of static analysis is diminishing for modern software, which heavily utilizes dynamic class loading, shared libraries, and runtime binding. Not only

Amarasinghe, Saman

53

Modeling and optimization of building HVAC systems.  

E-Print Network (OSTI)

??This thesis presents the development of hybrid modeling methodologies for HVAC component static/steady-state models and dynamic/transient models, and the development and implementation of a model-based… (more)

Jin, Guang Yu.

2012-01-01T23:59:59.000Z

54

Simple Dynamic Gasifier Model That Runs in Aspen Dynamics  

SciTech Connect

Gasification (or partial oxidation) is a vital component of 'clean coal' technology. Sulfur and nitrogen emissions can be reduced, overall energy efficiency is increased, and carbon dioxide recovery and sequestration are facilitated. Gasification units in an electric power generation plant produce a fuel for driving combustion turbines. Gasification units in a chemical plant generate gas, which can be used to produce a wide spectrum of chemical products. Future plants are predicted to be hybrid power/chemical plants with gasification as the key unit operation. The widely used process simulator Aspen Plus provides a library of models that can be used to develop an overall gasifier model that handles solids. So steady-state design and optimization studies of processes with gasifiers can be undertaken. This paper presents a simple approximate method for achieving the objective of having a gasifier model that can be exported into Aspen Dynamics. The basic idea is to use a high molecular weight hydrocarbon that is present in the Aspen library as a pseudofuel. This component should have the same 1:1 hydrogen-to-carbon ratio that is found in coal and biomass. For many plantwide dynamic studies, a rigorous high-fidelity dynamic model of the gasifier is not needed because its dynamics are very fast and the gasifier gas volume is a relatively small fraction of the total volume of the entire plant. The proposed approximate model captures the essential macroscale thermal, flow, composition, and pressure dynamics. This paper does not attempt to optimize the design or control of gasifiers but merely presents an idea of how to dynamically simulate coal gasification in an approximate way.

Robinson, P.J.; Luyben, W.L. [Lehigh University, Bethlehem, PA (United States). Dept. of Chemical Engineering

2008-10-15T23:59:59.000Z

55

Optimal entangling capacity of dynamical processes  

SciTech Connect

We investigate the entangling capacity of dynamical operations when provided with local ancilla. A comparison is made between the entangling capacity with and without the assistance of prior entanglement. An analytic solution is found for the log-negativity entangling capacity of two-qubit gates, which equals the entanglement of the Choi matrix isomorphic to the unitary operator. Surprisingly, the availability of prior entanglement does not affect this result, a property we call resource independence of the entangling capacity. We prove several useful upper bounds on the entangling capacity that hold for general qudit dynamical operations and for a whole family of entanglement monotones including log negativity and log robustness. The log-robustness entangling capacity is shown to be resource independent for general dynamics. We provide numerical results supporting a conjecture that the log-negativity entangling capacity is resource independent for all two-qudit unitary operators.

Campbell, Earl T. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)

2010-10-15T23:59:59.000Z

56

Optimal Entangling Capacity of Dynamical Processes  

E-Print Network (OSTI)

We investigate the entangling capacity of dynamical operations when provided with local ancilla. A comparison is made between the entangling capacity with and without the assistance of prior entanglement. An analytic solution is found for the log-negativity entangling capacity of two-qubit gates, which equals the entanglement of the Choi matrix isomorphic to the unitary operator. Surprisingly, the availability of prior entanglement does not affect this result; a property we call resource independence of the entangling capacity. We prove several useful upper-bounds on the entangling capacity that hold for general qudit dynamical operations, and for a whole family of entanglement monotones including log-negativity and log-robustness. The log-robustness entangling capacity is shown to be resource independent for general dynamics. We provide numerical results supporting a conjecture that the log-negativity entangling capacity is resource independence for all two-qudit unitaries.

Earl T. Campbell

2010-07-08T23:59:59.000Z

57

Parallel processing in discrimination between models of dynamic systems  

Science Conference Proceedings (OSTI)

The paper considers the problem of determining an optimal observation schedule for discrimination between competing models of a dynamic process. To this end, an approach originating in optimum experimental design is applied. Its use necessitates solving ...

Bartosz Kuczewski; Przemys?aw Baranowski; Dariusz Uci?ski

2005-09-01T23:59:59.000Z

58

Dynamic Mercury Cycling Model Upgrade  

Science Conference Proceedings (OSTI)

This technical update describes the status of activities to upgrade the Dynamic Mercury Cycling Model (D-MCM), an EPRI simulation model that predicts mercury cycling and bioaccumulation in lakes.

2008-12-17T23:59:59.000Z

59

Dynamic model for hydraulic dissipators  

Science Conference Proceedings (OSTI)

The authors propose a mathematical model of a hydraulic link with energy dissipation, the device working reversibly to the alternative traction and compression movement. The dynamic behavior of the energy hydraulic dissipater depends on the instantaneous ... Keywords: dissipater's control, dynamic behavior, hydraulic dissipater, mathematical model

Adrian S. Axinti; Gavril Axinti

2009-03-01T23:59:59.000Z

60

OPTCON: an algorithm for the optimal control of nonlinear stochastic models  

Science Conference Proceedings (OSTI)

Keywords: control algorithm, dynamic systems, nonlinear systems, optimal control, optimal economic policies, stochastic control

Josef Matulka; Reinhard Neck

1992-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamic optimization model" 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

HOMER: The Micropower Optimization Model. National Renewable...  

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

HOMER, the micro- power optimization model, helps you design off-grid and grid-connected systems. You can use HOMER to perform analyses to explore a wide range of design questions:...

62

Dynamic modeling of power systems  

Science Conference Proceedings (OSTI)

Morgantown Energy Technology Center`s (METC) Process and Project Engineering (P&PE) personnel continue to refine and modify dynamic modeling or simulations for advanced power systems. P&PE, supported by Gilbert/Commonwealth, Inc. (G/C), has adapted PC/TRAX commercial dynamic software to include equipment found in advanced power systems. PC/TRAX`s software contains the equations that describe the operation of standard power plant equipment such as gas turbines, feedwater pumps, and steam turbines. The METC team has incorporated customized dynamic models using Advanced Continuous Simulation Language (ACSL) code for pressurized circulating fluidized-bed combustors, carbonizers, and other components that are found in Advanced Pressurized Fluidized-Bed Combustion (APFBC) systems. A dynamic model of a commercial-size APFBC power plant was constructed in order to determine representative operating characteristics of the plant and to gain some insight into the best type of control system design. The dynamic model contains both process and control model components. This presentation covers development of a model used to describe the commercial APFBC power plant. Results of exercising the model to simulate plant performance are described and illustrated. Information gained during the APFBC study was applied to a dynamic model of a 1-1/2 generation PFBC system. Some initial results from this study are also presented.

Reed, M.; White, J.

1995-12-01T23:59:59.000Z

63

Optimal Consumption Problem in a Diffusion Short-Rate Model  

E-Print Network (OSTI)

We consider a problem of an optimal consumption strategy on the infinite time horizon when the short-rate is a diffusion process. General existence and uniqueness theorem is illustrated by the Vasicek and so-called invariant interval models. We show also that when the short-rate dynamics is given by a Brownian motion or a geometric Brownian motion, then the value function is infinite.

Synowiec, Daniel

2009-01-01T23:59:59.000Z

64

Efficient Production Optimization Using Flow Network Models  

E-Print Network (OSTI)

Reservoir simulation is an important tool for decision making and field development management. It enables reservoir engineers to predict reservoir production performance, update an existing model to reproduce monitoring data, assess alternative field development scenarios and design robust production optimization strategies by taking into account the existing uncertainties. A big obstacle in automating model calibration and production optimization approaches is the massive computation required to predict the response of real reservoirs under proposed changes in the model inputs. To speed up reservoir response predictions without compromising accuracy, fast surrogate models have been proposed. These models are either derived by preserving the physics of the involved processes (e.g. mass balance equations) to provide reliable long-range predictions or are developed based solely on statistical relations, in which case they can only provide short-range predictions due to the absence of the physical processes that govern the long-term behavior of the reservoir. We present an alternative solution that combines the advantages of both statistics-based and physics-based methods by deriving the flow predictions in complex two-dimensional models from one-dimensional flow network models. The existing injection/production wells in the original model form the nodes or vertices of the flow network. Each pair of wells (nodes) in the flow network is connected using a one-dimensional numerical simulation model; hence, the entire reservoir is reduced to a connected network of one-dimensional simulation models where the coupling between the individual one-dimensional models is enforced at the nodes where network edges intersect. The proposed flow network model provides a useful and fast tool for characterizing inter-well connectivity, estimating drainage volume between each pair of wells, and predicting reservoir production over an extended period of time for optimization purposes. We estimate the parameters of the flow network model using a robust training approach to ensure that the flow network model reproduces the response of the original full model under a wide range of development strategies. This step helps preserve the flow network model's predictive power during the production optimization when development strategies can change at different iterations. The robust networks training and the subsequent production optimization iterations are computationally efficient as they are performed with the faster flow network model. We demonstrate the effectiveness and applicability of our proposed flow network modeling approach to rapid production optimization using two-phase waterflooding simulations in synthetic and benchmark models.

Lerlertpakdee, Pongsathorn

2012-08-01T23:59:59.000Z

65

Optimal statistical model for forecasting ozone  

Science Conference Proceedings (OSTI)

The objective of this paper is to apply time series analysis and multiple regression method to ozone data in order to obtain the optimal statistical model for forecasting next day ozone level. The best estimated model is then used to produce one-step ... Keywords: ARMA (p, q), Durbin-Watson Statistic, MAPE, R-square, multiple regression

M. Abdollahian; R. Foroughi; N. Debnath

2006-04-01T23:59:59.000Z

66

Optimality of Myopic Policies for Dynamic Lot-Sizing Problems in Serial Production Lines with Random Yields and Autoregressive Demand  

Science Conference Proceedings (OSTI)

We study lot-size policies in a serial, multistage manufacturing/inventory system with two key generalizations, namely 1 random yields at each production stage and 2 an autoregressive demand process. Previous research shows that the optimal policies ... Keywords: dynamic programming/optimal control, inventory/production, models, multi-item/echelon/stage, perishable/aging items

Matthew J. Sobel; Volodymyr Babich

2012-11-01T23:59:59.000Z

67

Dynamic competition model for construction contractors  

E-Print Network (OSTI)

Dynamic competition in an industry has been an interest of practitioners and researchers because of the expectation that sound understanding of competition in a dynamic way enables a firm to compete better. This dynamic approach considers a firm as an entity in a dynamic system, in which every entity is a profit optimizer responding to market conditions as well as its competitors' actions. In construction, the issue of competition has been focused on competitive bidding, which is a critical mechanism for a contractor to obtain jobs and to generate profits by performing them. Since Friedman's competitive bidding model (1956), various approaches have been developed to improve earlier models. The objective of most models is to find the optimum markup to maximize the expected profit from a firm's perspective. However, to better understand competition in the market, there is the need to analyze this issue from a market perspective. The market perspective provides the consideration about market equilibrium. From previous models and other competition studies, critical missing concepts were identified. In order to find efficient policies that enable a firm to outperform its competitors and to provide an analytical framework of understanding dynamic competition, a system dynamics model has been developed based on the identified concepts. In this model, there are three managerial areas in which a contractor makes policy: 1) markup; 2) marketing; and 3) capacity. Each firm's backlog level is considered as a basic input to its policy making. N firms are equally exposed to demand uncertainty. As an optimizer, each firm applies its policies responding to changes in the market to keep its operations efficient. Firms' responses to market changes are simulated and analyzed and their dynamic feedback was studied. Test results show how difficult it is for a firm to obtain a competitive advantage competing with its competitors due to their reactions. This is different from the previous models that determine a better policy based on assumed static condition and ignorance of competitors' reactions. The test results also show the possibility that one firm can outperform its competitors by using different policies based on accurate market forecasts.

Kim, Hyung Jin

2004-01-01T23:59:59.000Z

68

Optimal Control of a Parabolic Equation with Dynamic Boundary Condition  

SciTech Connect

We investigate a control problem for the heat equation. The goal is to find an optimal heat transfer coefficient in the dynamic boundary condition such that a desired temperature distribution at the boundary is adhered. To this end we consider a function space setting in which the heat flux across the boundary is forced to be an L{sup p} function with respect to the surface measure, which in turn implies higher regularity for the time derivative of temperature. We show that the corresponding elliptic operator generates a strongly continuous semigroup of contractions and apply the concept of maximal parabolic regularity. This allows to show the existence of an optimal control and the derivation of necessary and sufficient optimality conditions.

Hoemberg, D., E-mail: hoemberg@wias-berlin.de; Krumbiegel, K., E-mail: krumbieg@wias-berlin.de [Weierstrass Institute for Applied Mathematics and Stochastics, Nonlinear Optimization and Inverse Problems (Germany); Rehberg, J., E-mail: rehberg@wias-berlin.de [Weierstrass Institute for Applied Mathematics and Stochastics, Partial Differential Equations (Germany)

2013-02-15T23:59:59.000Z

69

Object Library of Algorithms for Dynamic Optimization Problems: Benchmarking SQP and Nonlinear Interior Point Methods  

Science Conference Proceedings (OSTI)

The main purpose of this paper is to describe the design, implementation and possibilities of our object-oriented library of algorithms for dynamic optimization problems. We briefly present library classes for the formulation and manipulation of dynamic ... Keywords: Automatic Differentiation, Dynamic Optimization, Large-Scale Optimization, Nonlinear Interior-Point Methods, Object-Oriented Numerical Computations, Performance Data Analysis, Sequential Quadratic Programming

Jacek B?Aszczyk; Andrzej Karbowski; Krzysztof Malinowski

2007-12-01T23:59:59.000Z

70

Python Optimization Modeling Objects (Pyomo)  

E-Print Network (OSTI)

Dec 29, 2009 ... support open source analysis tools, limitations for software deployment on classified computers, and ..... This command summarizes the information in the Pyomo model, but it does not print ..... mstr inst . market [p , t ] \\ .... a Lockheed Martin Company, for the United States Department of Energy's National.

71

Dynamic analysis for the selection of parameters and initial population, in particle swarm optimization  

Science Conference Proceedings (OSTI)

In this paper we consider the evolutionary Particle Swarm Optimization (PSO) algorithm, for the minimization of a computationally costly nonlinear function, in global optimization frameworks. We study a reformulation of the standard iteration ... Keywords: Convergence analysis, Dynamic linear system, Evolutionary optimization, Global optimization, Particle Swarm Optimization

Emilio F. Campana; Giovanni Fasano; Antonio Pinto

2010-11-01T23:59:59.000Z

72

Hybrid Model for Building Performance Diagnosis and Optimal Control  

E-Print Network (OSTI)

Modern buildings require continuous performance monitoring, automatic diagnostics and optimal supervisory control. For these applications, simplified dynamic building models are needed to predict the cooling and heating requirement viewing the building as a whole system. This paper proposes a new hybrid model. Half of the model is represented by detailed physical parameters and another half is described by identified parameters. 3R2C thermal network model, which consists of three resistances and two capacitances, is used to simulate building envelope whose parameters are determined in frequency domain using the theoretical frequency characteristics of the envelope. Internal mass is represented by a 2R2C thermal network model, which consists of three resistances and two capacitances. The resistances and capacitances of the 2R2C model are assumed to be constant. A GA (genetic algorithm)-based method is developed for model parameter identification by searching the optimal parameters of 3R2C models of envelopes in frequency domain and that of the 2R2C model of the building internal mass in time domain. As the model is based on the physical characteristics, the hybrid model can be used to predict the cooling and heating energy consumption of buildings accurately in wide range of operation conditions.

Wang, S.; Xu, X.

2003-01-01T23:59:59.000Z

73

CFD optimization for GDI spray model tuning and enhancement of engine performance  

Science Conference Proceedings (OSTI)

Coupling a 3D Computational Fluid Dynamics (CFD) tool with a rigorous method of decision making is becoming indispensable in the design process of complex systems, as internal combustion engines. CFD based optimization (CFD-O) is here carried out on ... Keywords: CFD based optimization, Charge stratification, Gasoline direct injection, Multidimensional modelling, Spark ignition engines, Split injection

M. Costa; U. Sorge; L. Allocca

2012-07-01T23:59:59.000Z

74

Robust and Stochastically Weighted Multiobjective Optimization Models and Reformulations  

Science Conference Proceedings (OSTI)

We introduce and study a family of models for multiexpert multiobjective/criteria decision making. These models use a concept of weight robustness to generate a risk-averse decision. In particular, the multiexpert multicriteria robust weighted sum approach ... Keywords: McRow, Pareto optimality, multicriterion optimization, multiexpert optimization, robust optimization, weighted sum method

Jian Hu; Sanjay Mehrotra

2012-07-01T23:59:59.000Z

75

Optimal Control Design with Limited Model Information  

E-Print Network (OSTI)

We introduce the family of limited model information control design methods, which construct controllers by accessing the plant's model in a constrained way, according to a given design graph. We investigate the achievable closed-loop performance of discrete-time linear time-invariant plants under a separable quadratic cost performance measure with structured static state-feedback controllers. We find the optimal control design strategy (in terms of the competitive ratio and domination metrics) when the control designer has access to the local model information and the global interconnection structure of the plant-to-be-controlled. At last, we study the trade-off between the amount of model information exploited by a control design method and the best closed-loop performance (in terms of the competitive ratio) of controllers it can produce.

Farokhi, F; Johansson, K H

2011-01-01T23:59:59.000Z

76

A generative model for dynamic canvas motion  

Science Conference Proceedings (OSTI)

We present techniques for constructing realistic canvas and paper models and for enabling interactive dynamic canvas motion. Dynamic canvas motion means that there is a correspondence between the motion of canvas features and the motion of the models ...

Matthew Kaplan; Elaine Cohen

2005-05-01T23:59:59.000Z

77

Evolutionary Dynamic Optimization: A Survey of the State of the Art  

E-Print Network (OSTI)

May 24, 2012 ... Evolutionary computation and swarm intelligence are good tools to address optimization problems in dynamic environments due to their ...

78

Dynamic Process of Money Transfer Models  

E-Print Network (OSTI)

We have studied numerically the statistical mechanics of the dynamic phenomena, including money circulation and economic mobility, in some transfer models. The models on which our investigations were performed are the basic model proposed by A. Dragulescu and V. Yakovenko [1], the model with uniform saving rate developed by A. Chakraborti and B.K. Chakrabarti [2], and its extended model with diverse saving rate [3]. The velocity of circulation is found to be inversely related with the average holding time of money. In order to check the nature of money transferring process in these models, we demonstrated the probability distributions of holding time. In the model with uniform saving rate, the distribution obeys exponential law, which indicates money transfer here is a kind of Poisson process. But when the saving rate is set diversely, the holding time distribution follows a power law. The velocity can also be deduced from a typical individual's optimal choice. In this way, an approach for building the micro-...

Wang, Y; Wang, Yougui; Ding, Ning

2005-01-01T23:59:59.000Z

79

Provably near-optimal algorithms for multi-stage stochastic optimization models in operations management  

E-Print Network (OSTI)

Many if not most of the core problems studied in operations management fall into the category of multi-stage stochastic optimization models, whereby one considers multiple, often correlated decisions to optimize a particular ...

Shi, Cong, Ph.D. Massachusetts Institute of Technology

2012-01-01T23:59:59.000Z

80

Generating exact D-optimal designs for polynomial models  

Science Conference Proceedings (OSTI)

This paper compares several optimization algorithms that can be used to generate exact D-optimal designs (i.e., designs for a specified number of runs) for any polynomial model. The merits and limitations of each algorithm are demonstrated on ... Keywords: general linear regression, mathematical optimization, optimal experimental design

Jacob E. Boon

2007-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamic optimization model" 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

Development and Control of Autonomous, Biped Locomotion using Efficient Modeling, Simulation, and Optimization Techniques  

E-Print Network (OSTI)

. The optimization of the stability or energy performance indices subject to the system dynamics and constraints

Stryk, Oskar von

82

Surrogate modeling in the evolutionary optimization of catalytic materials  

Science Conference Proceedings (OSTI)

The search for best performing catalysts leads to high-dimensional optimization tasks. They are by far most frequently tackled using evolutionary algorithms, usually implemented in systems developed specifically for the area of catalysis. Their fitness ... Keywords: applications in chemistry, evolutionary optimization, mixed optimization, model suitability, surrogate modelling

Martin Holena; David Linke; Lukas Bajer

2012-07-01T23:59:59.000Z

83

A self-organizing random immigrants genetic algorithm for dynamic optimization problems  

Science Conference Proceedings (OSTI)

In this paper a genetic algorithm is proposed where the worst individual and individuals with indices close to its index are replaced in every generation by randomly generated individuals for dynamic optimization problems. In the proposed genetic algorithm, ... Keywords: Dynamic optimization problems, Genetic algorithms, Random immigrants, Self-organized criticality

Renato Tinós; Shengxiang Yang

2007-09-01T23:59:59.000Z

84

15.094 Systems Optimization: Models and Computation, Spring 2002  

E-Print Network (OSTI)

A computational and application-oriented introduction to the modeling of large-scale systems in a wide variety of decision-making domains and the optimization of such systems using state-of-the-art optimization software. ...

Freund, Robert Michael

85

Bayesian inference of stochastic dynamical models  

E-Print Network (OSTI)

A new methodology for Bayesian inference of stochastic dynamical models is developed. The methodology leverages the dynamically orthogonal (DO) evolution equations for reduced-dimension uncertainty evolution and the Gaussian ...

Lu, Peter Guang Yi

2013-01-01T23:59:59.000Z

86

Photocathode Optimization for a Dynamic Transmission Electron Microscope: Final Report  

SciTech Connect

The Dynamic Transmission Electron Microscope (DTEM) team at Harvey Mudd College has been sponsored by LLNL to design and build a test setup for optimizing the performance of the DTEM's electron source. Unlike a traditional TEM, the DTEM achieves much faster exposure times by using photoemission from a photocathode to produce electrons for imaging. The DTEM team's work is motivated by the need to improve the coherence and current density of the electron cloud produced by the electron gun in order to increase the image resolution and contrast achievable by DTEM. The photoemission test setup is nearly complete and the team will soon complete baseline tests of electron gun performance. The photoemission laser and high voltage power supply have been repaired; the optics path for relaying the laser to the photocathode has been finalized, assembled, and aligned; the internal setup of the vacuum chamber has been finalized and mostly implemented; and system control, synchronization, and data acquisition has been implemented in LabVIEW. Immediate future work includes determining a consistent alignment procedure to place the laser waist on the photocathode, and taking baseline performance measurements of the tantalum photocathode. Future research will examine the performance of the electron gun as a function of the photoemission laser profile, the photocathode material, and the geometry and voltages of the accelerating and focusing components in the electron gun. This report presents the team's progress and outlines the work that remains.

Ellis, P; Flom, Z; Heinselman, K; Nguyen, T; Tung, S; Haskell, R; Reed, B W; LaGrange, T

2011-08-04T23:59:59.000Z

87

Timing modeling and optimization under the transmission line model  

E-Print Network (OSTI)

Abstract—As the operating frequency increases to gigahertz and the rise time of a signal is less than or comparable to the time-of-flight delay of a wire, it is necessary to consider the transmission line behavior for delay computation. We present in this paper, an analytical formula for the delay computation under the transmission line model. Extensive simulations with SPICE show the high fidelity of the formula. Compared with previous works, our model leads to smaller average errors in delay estimation. Based on this formula, we show the property that the minimum delay for a transmission line with reflection occurs when the number of round trips is minimized (i.e., equals one). Besides, we show that the delay of a circuit path is a posynomial function in wire and buffer sizes, implying that a local optimum is equal to the global optimum. Thus, we can apply any efficient search algorithm such as the well-known gradient search procedure to compute the globally optimal solution. Experimental results show that simultaneous wire and buffer sizing is very effective for performance optimization under the transmission line model. Index Terms—Buffer sizing, delay model, inductance, interconnect, performance optimization, transmission line, wire sizing.

Tai-chen Chen; Song-ra Pan; Yao-wen Chang

2004-01-01T23:59:59.000Z

88

Optimizing reservoir management through fracture modeling  

DOE Green Energy (OSTI)

Fracture flow will become increasingly important to optimal reservoir management as exploration of geothermal reservoirs continues and as injection of spent fluid increases. The Department of Energy conducts research focused on locating and characterizing fractures, modeling the effects of fractures on movement of fluid, solutes, and heat throughout a reservoir, and determining the effects of injection on long-term reservoir production characteristics in order to increase the ability to predict with greater certainty the long-term performance of geothermal reservoirs. Improvements in interpreting and modeling geophysical techniques such as gravity, self potential, and aeromagnetics are yielding new information for the delineation of active major conduits for fluid flow. Vertical seismic profiling and cross-borehole electromagnetic techniques also show promise for delineating fracture zones. DOE funds several efforts for simulating geothermal reservoirs. Lawrence Berkeley Laboratory has adopted a continuum treatment for reservoirs with a fracture component. Idaho National Engineering Laboratory has developed simulation techniques which utilize discrete fractures and interchange of fluid between permeable matrix and fractures. Results of these research projects will be presented to industry through publications and appropriate public meetings. 9 refs.

Renner, J.L.

1988-01-01T23:59:59.000Z

89

Advanced Software for Nonlinear Systems Modeling and Optimization  

E-Print Network (OSTI)

Dec 16, 2004... [-3,3]2; observe also the location of the optimal solution (green dot). ... potential energy models in computational chemistry (Pintér, 2000, ...

90

Optimization Online - Use of quadratic models with mesh adaptive ...  

E-Print Network (OSTI)

Mar 6, 2011 ... Use of quadratic models with mesh adaptive direct search for constrained black box optimization. Andrew R Conn (arconn ***at*** us.ibm.com)

91

Through-process Modeling for Cold Spray Alloy Optimization  

Science Conference Proceedings (OSTI)

Presentation Title, Through-process Modeling for Cold Spray Alloy Optimization ... repairability, and energy efficiency are highly desirable in many industries.

92

Dynamic optimization for commercialization of renewable energy: an example for solar photovoltaics  

DOE Green Energy (OSTI)

There are several studies of optimal allocation of research and development resources over the time horizon of a project. The primary result of the basic noncompetitive models in this literature is that the optimal strategy is to choose a research intensity and ending date for the project such that the marginal costs of accelerating the project equals the marginal benefits of introducing the product sooner. This literature provides useful insights for the government planner who must allocate R&D resources for renewable energy development. However, several characteristics distinguish the process from the typical R&D planning problem. Specifically, with PV development, where the goal is to maximize the net present value of activities leading to cost reduction in commercial modules, there are (1) significant lag-times between investment in laboratory research and resulting effects in the marketplace, (2) a learning curve associated with the manufacturing process that also reduces the cost s of PV modules, (3) interim benefits from technical advances, (4) no clear end point to the R&D process, but rather a tapering off of the value of advances in technical efficiency, (5) significant uncertainty in the R&D process, (6) a family of products rather than an individual technology, (7) a co-mingling of government and private resources with implications for efficient management. A dynamic model is developed to characterize the optimal intensity and timing of government and private resource allocation for basic research in improving the technical efficiency of cells and subsidies to the manufacturing process to encourage progress on the learning curve. A series of propositions regarding optimal paths for each are examined. While the research is purely analytical, the results are useful for conceptualizing the R&D planning process. They also provide a basis for a numerical study that can address whether current levels and historic patterns of funding are optimal.

Richards, Kenneth, R.; Ashton, W. Bradley; McVeigh, James

2000-04-21T23:59:59.000Z

93

Modeling recreational systems using optimization techniques and ...  

E-Print Network (OSTI)

E-mail: oleg.shcherbina@univie.ac.at. E. Shembeleva. University of ...... 43. Godart, J.-M. (2005). Challenges in Real World Sightseeing Tour Optimization Using.

94

Optimization Online - Nonlinear Model Predictive Control via ...  

E-Print Network (OSTI)

Aug 15, 2002 ... Citation: Optimization Technical Report 02-06, August, 2002, Computer Sciences Department, University of Wisconsin. Texas-Wisconsin ...

95

Cogeneration System Size Optimization Constant Capacity and Constant Demand Models  

E-Print Network (OSTI)

This paper presents the development of a quasi-linear optimization model for a cogeneration system subject to constant heat and power demands or loads. The linear model is next modified to a non-linear one to account for economies of scale. The models define the necessary and sufficient conditions for system size optimality. Thus, the underlying methodology constitutes the foundation for a subsequent series of more sophisticated cogeneration design models. Several examples are presented to illustrate the models.

Wong-Kcomt, J. B.; Turner, W. C.

1993-03-01T23:59:59.000Z

96

Optimization Online - Dynamic sampling algorithms for multi-stage ...  

E-Print Network (OSTI)

Dec 18, 2010... of hydro-thermal scheduling in the New Zealand electricity system. ... Citation: Technical report, Electric Power Optimization Centre, ...

97

Dynamic LES Modeling of a Diurnal Cycle  

Science Conference Proceedings (OSTI)

The diurnally varying atmospheric boundary layer observed during the Wangara (Australia) case study is simulated using the recently proposed locally averaged scale-dependent dynamic subgrid-scale (SGS) model. This tuning-free SGS model enables ...

Sukanta Basu; Jean-François Vinuesa; Andrew Swift

2008-04-01T23:59:59.000Z

98

A Dynamic Model of Thundercloud Electric Fields  

Science Conference Proceedings (OSTI)

A dynamic interactive computer model of the electrical behavior of a thundercloud surrounded by the distributed atmosphere, earth, ionosphere circuit is described. The electrification mechanisms in the model are represented by current or voltage ...

John S. Nisbet

1983-12-01T23:59:59.000Z

99

Dynamical Properties of Model Output Statistics Forecasts  

Science Conference Proceedings (OSTI)

The dynamical properties of forecasts corrected using model output statistics (MOS) schemes are explored, with emphasis on the respective role of model and initial condition uncertainties. Analytical and numerical investigations of low-order ...

S. Vannitsem; C. Nicolis

2008-02-01T23:59:59.000Z

100

Common Information Model (CIM) for Dynamics: Standard Models  

Science Conference Proceedings (OSTI)

This report describes the work accomplished in 2011 and 2012 to develop a standard approach for the exchange of dynamic models and their association to a static power flow model based on the International Electrotechnical Commission (IEC) 61970 Common Information Model (CIM) standards. These exchange models represent the dynamic behavior of the majority of power system components in common use today by electric utilities to perform system simulation studies for system dynamic assessment and for ...

2013-02-05T23:59:59.000Z

Note: This page contains sample records for the topic "dynamic optimization model" 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

The Challenges to Coupling Dynamic Geospatial Models  

SciTech Connect

Many applications of modeling spatial dynamic systems focus on a single system and a single process, ignoring the geographic and systemic context of the processes being modeled. A solution to this problem is the coupled modeling of spatial dynamic systems. Coupled modeling is challenging for both technical reasons, as well as conceptual reasons. This paper explores the benefits and challenges to coupling or linking spatial dynamic models, from loose coupling, where information transfer between models is done by hand, to tight coupling, where two (or more) models are merged as one. To illustrate the challenges, a coupled model of Urbanization and Wildfire Risk is presented. This model, called Vesta, was applied to the Santa Barbara, California region (using real geospatial data), where Urbanization and Wildfires occur and recur, respectively. The preliminary results of the model coupling illustrate that coupled modeling can lead to insight into the consequences of processes acting on their own.

Goldstein, N

2006-06-23T23:59:59.000Z

102

Combining stochastic dynamic programming (SDP) and artificial neural networks (ANN) in optimal reservoir operation  

Science Conference Proceedings (OSTI)

After development of any optimization model a post-optimization simulation is needed for two purposes: 1) Checking and evaluating of system performance and 2) Computing performance criteria. The common rule is developing a simulation model in the form ... Keywords: ANN, SDP, optimal reservoir operation

Omid Bozorg Haddad; Saeed Alimohammadi

2005-06-01T23:59:59.000Z

103

Performance analysis and optimization of molecular dynamics simulation on Godson-T many-core processor  

Science Conference Proceedings (OSTI)

Molecular dynamics (MD) simulation has broad applications, but its irregular memory-access pattern makes performance optimization a challenge. This paper presents a joint application/architecture study to enhance on-chip parallelism of MD on Godson-T ...

Liu Peng; Aiichiro Nakano; Guangming Tan; Priya Vashishta; Dongrui Fan; Hao Zhang; Rajiv K. Kalia; Fenglong Song

2011-05-01T23:59:59.000Z

104

Distributed optimal dynamic base station positioning in wireless sensor networks  

Science Conference Proceedings (OSTI)

Base station (BS) positioning is an effective method for improving the performance of wireless sensor networks (WSNs). A metric-aware optimal BS positioning and relocation mechanism for WSNs is proposed. This technique locates the BS with respect to ... Keywords: Base station placement, Base station relocation, Least-squares optimization, Wireless sensor networks

P. D. Hossein Zadeh; C. Schlegel; M. H. MacGregor

2012-01-01T23:59:59.000Z

105

An 'optimal' spawning algorithm for adaptive basis set expansion in nonadiabatic dynamics  

Science Conference Proceedings (OSTI)

The full multiple spawning (FMS) method has been developed to simulate quantum dynamics in the multistate electronic problem. In FMS, the nuclear wave function is represented in a basis of coupled, frozen Gaussians, and a 'spawning' procedure prescribes a means of adaptively increasing the size of this basis in order to capture population transfer between electronic states. Herein we detail a new algorithm for specifying the initial conditions of newly spawned basis functions that minimizes the number of spawned basis functions needed for convergence. 'Optimally' spawned basis functions are placed to maximize the coupling between parent and child trajectories at the point of spawning. The method is tested with a two-state, one-mode avoided crossing model and a two-state, two-mode conical intersection model.

Yang, Sandy; Coe, Joshua D.; Kaduk, Benjamin; Martinez, Todd J. [Department of Chemistry and Beckman Institute, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, Illinois 61801 (United States)

2009-04-07T23:59:59.000Z

106

Optimization models of gas recovery and gas condensate processing  

Science Conference Proceedings (OSTI)

We present a complex of mathematical models that formalize gas recovery and processing. Optimization problems for gas recovery and gas condensate processing are stated and corresponding solution algorithms are suggested. These mathematical models provide ...

M. Kh. Prilutskii; V. E. Kostyukov

2012-05-01T23:59:59.000Z

107

Local energy management through mathematical modeling and optimization  

E-Print Network (OSTI)

(cont.) Extensions to the core TOTEM model include a demand charge model, used for making daily optimal control decisions when the electric bill includes a charge based on the monthly maximum power draw. The problem of ...

Craft David (David Loren), 1973-

2004-01-01T23:59:59.000Z

108

Online Modeling in the Process Industry for Energy Optimization  

E-Print Network (OSTI)

"This paper discusses how steady state models are being used in the process industry to perform online energy optimization of steam and electrical systems. It presents process demands commonly found in the processing industry in terms of steam and electricity. It further discusses the methods of providing this energy for refineries, petrochemical plants, and other processing plants - chemical, paper, and metal. A typical system flow diagram is used to highlight the energy system network and describe areas where steady-state models are used. The types of models used are discussed, and a scheme for putting the models together to provide total process plant energy optimization is summarized. The types of optimization which can be implemented in a process plant is thus presented. The paper points out what steady-state modeling is needed to do online optimization of an energy network in a processing plant. Finally, a discussion of the economics on online energy optimization is presented."

Alexander, J.

1988-09-01T23:59:59.000Z

109

A partitioner-centric model for SAMR partitioning trade-off optimization : Part II.  

SciTech Connect

Optimal partitioning of structured adaptive mesh applications necessitates dynamically determining and optimizing for the most time-inhibiting factor, such as data migration and communication volume. However, a trivial monitoring of an application evaluates the current partitioning rather than the inherent properties of the grid hierarchy. We present a model that given a structured adaptive grid, determines ab initio to what extent the partitioner should focus on reducing the amount of data migration to reduce execution time. This model contributes to the meta-partitioner, our ultimate aim of being able to select and configure the optimal partitioner based on the dynamic properties of the grid hierarchy and the computer. We validate the predictions of this model by comparing them with actual measurements (via traces) from four different adaptive simulations. The results show that the proposed model generally captures the inherent optimization-need in SAMR applications. We conclude that our model is a useful contribution, since tracking and adapting to the dynamic behavior of such applications lead to potentially large decreases in execution times.

Steensland, Johan; Ray, Jaideep

2004-03-01T23:59:59.000Z

110

Dynamic programming for constrained optimal control of discrete-time linear hybrid systems  

Science Conference Proceedings (OSTI)

In this paper we study the solution to optimal control problems for constrained discrete-time linear hybrid systems based on quadratic or linear performance criteria. The aim of the paper is twofold. First, we give basic theoretical results on the structure ... Keywords: Dynamic programming, Hybrid systems, Multiparametric programming, Optimal control, Piecewise affine systems

Francesco Borrelli; Mato Baoti?; Alberto Bemporad; Manfred Morari

2005-10-01T23:59:59.000Z

111

Imperialist competitive algorithm for dynamic optimization of economic dispatch in power systems  

Science Conference Proceedings (OSTI)

As energy costs are expected to keep rising in the coming years, mostly due to a growing worldwide demand, optimizing power generation is of crucial importance for utilities. Economic power dispatch is a tool commonly used by electric power plant operators ... Keywords: dynamic optimization, economic dispatch, imperialist competitive algorithm, metaheuristic, microgrid

Robin Roche; Lhassane Idoumghar; Benjamin Blunier; Abdellatif Miraoui

2011-10-01T23:59:59.000Z

112

A memetic algorithm for optimal dynamic design of wireless sensor networks  

Science Conference Proceedings (OSTI)

We present a memetic algorithm that dynamically optimizes the design of a wireless sensor network towards energy conservation and extension of the life span of the network, taking into consideration application-specific requirements, communication constraints ... Keywords: Design optimization, Energy conservation, Memetic algorithms, Wireless sensor networks

Konstantinos P. Ferentinos; Theodore A. Tsiligiridis

2010-02-01T23:59:59.000Z

113

A flexible and dynamic algorithm for assessment and optimization of utility sectors  

Science Conference Proceedings (OSTI)

This paper presents a flexible and dynamic algorithm for total assessment, ranking, and optimization of utility sectors. Data envelopment analysis (DEA), corrected ordinary least square (COLS), and stochastic frontier analysis (SFA) are employed for ... Keywords: Assessment, Corrected ordinary least squares, Data envelopment analysis, Optimization, Stochastic frontier analysis, Utility sector

A. Azadeh; H. Eivazy; M. Moghaddam

2010-11-01T23:59:59.000Z

114

Optimization Online - On the Dynamic Stability of Electricity Markets  

E-Print Network (OSTI)

Jan 31, 2011 ... On the Dynamic Stability of Electricity Markets. Victor M. Zavala (vzavala ***at*** mcs.anl.gov) Mihai Anitescu (anitescu ***at*** mcs.anl.gov).

115

Dynamic Equilibrium Economies: A Framework for Comparing Models and Data  

E-Print Network (OSTI)

: We propose a constructive, multivariate framework for assessing agreement between (generally misspecified) dynamic equilibrium models and data, which enables a complete second-order comparison of the dynamic properties of models and data. We use bootstrap algorithms to evaluate the significance of deviations between models and data, and we use goodness-of-fit criteria to produce estimators that optimize economically-relevant loss functions. We provide a detailed illustrative application to modeling the U.S. cattle cycle. Acknowledgments: The Co-Editor and referees provided helpful and constructive input, as did participants at meetings of the Econometric Society, the CEPR, the NBER, and numerous university seminars. We gratefully acknowledge additional help from Bill Brown, Fabio Canova, Tim Cogley, Bob Lucas, Ellen McGrattan, Danny Quah, Lucrezia Reichlin, Sherwin Rosen, Chris Sims, Tony Smith, Jim Stock, Mark Watson, and especially Lars Hansen, Adrian Pagan, and Tom Sargent. All re...

Lee E. Ohanian; Jeremy Berkowitz; Francis X. Diebold; Francis X. Diebold; Tim Cogley; Bob Lucas; Ellen Mcgrattan; Danny Quah; Lucrezia Reichlin

1998-01-01T23:59:59.000Z

116

Very Large System Dynamics Models - Lessons Learned  

Science Conference Proceedings (OSTI)

This paper provides lessons learned from developing several large system dynamics (SD) models. System dynamics modeling practice emphasize the need to keep models small so that they are manageable and understandable. This practice is generally reasonable and prudent; however, there are times that large SD models are necessary. This paper outlines two large SD projects that were done at two Department of Energy National Laboratories, the Idaho National Laboratory and Sandia National Laboratories. This paper summarizes the models and then discusses some of the valuable lessons learned during these two modeling efforts.

Jacob J. Jacobson; Leonard Malczynski

2008-10-01T23:59:59.000Z

117

Optimal Compensation Algorithms for a Dynamic Voltage Restorer  

Science Conference Proceedings (OSTI)

The Dynamic Voltage Restorer (DVR) as an electronics based custom device, is used to protect sensitive loads from the voltage sags in the power distribution system. With the rapid technology advancement in industrial control processes, it is experiencing ... Keywords: Dynamic Voltage Restorer (DVR), power quality, voltage sag, Zero Active Power Compensation (ZAPC), Minimal Active Power Compensation (MAPC)

Deng Pan; Chen Zhongming; Jiang Peng; Abdelkrim Benchaib; Guillaume De Preville

2010-06-01T23:59:59.000Z

118

Optimal dynamic vertical ray shooting in rectilinear planar subdivisions  

Science Conference Proceedings (OSTI)

In this paper we consider the dynamic vertical ray shooting problem, that is the task of maintaining a dynamic set S of n non intersecting horizontal line segments in the plane subject to a query that reports the first segment in S ...

Yoav Giyora; Haim Kaplan

2007-01-01T23:59:59.000Z

119

Gain-scheduled `1 -optimal control for boiler-turbine dynamics  

E-Print Network (OSTI)

Gain-scheduled `1 -optimal control for boiler-turbine dynamics with actuator saturation Pang; accepted 2 June 2003 Abstract This paper presents a gain-scheduled approach for boiler-turbine controller the magnitude and rate saturation constraints on actuators. The nonlinear boiler-turbine dynamics is brought

Shamma, Jeff S.

120

Stochastic Optimization Models for Rapid Detection of Viruses in Cellphone Networks  

E-Print Network (OSTI)

We develop a class of models to represent the dynamics of a virus spreading in a cellphone network, employing a taxonomy that includes five key characteristics. Based on the resulting dynamics governing the spread, we present optimization models to rapidly detect the virus, subject to resource limitations. We consider two goals, maximizing the probability of detecting a virus by a time threshold and minimizing the expected time to detection, which can be applied to all spread models we consider. We establish a submodularity result for these two objective functions that ensures that a greedy algorithm yields a well-known constant-factor (63%) approximation. We relate the latter optimization problem, under a specific virus-spread mechanism from our class of models, to a classic facility-location model. And, for the former objective function, we provide a sample-path optimization model that yields an asymptotically-optimal design for locating the detection devices, as the number of samples grows large. Finally, using call data from a large carrier, we estimate the degree distribution in a contact network, which is central to building random networks to study our models and solution methods. 1

Jinho Lee; John J. Hasenbein; David P. Morton

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamic optimization model" 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

Optimization of a Two-Fluid Hydrodynamic Model of Churn-Turbulent Flow  

DOE Green Energy (OSTI)

A hydrodynamic model of two-phase, churn-turbulent flows is being developed using the computational multiphase fluid dynamics (CMFD) code, NPHASE-CMFD. The numerical solutions obtained by this model are compared with experimental data obtained at the TOPFLOW facility of the Institute of Safety Research at the Forschungszentrum Dresden-Rossendorf. The TOPFLOW data is a high quality experimental database of upward, co-current air-water flows in a vertical pipe suitable for validation of computational fluid dynamics (CFD) codes. A five-field CMFD model was developed for the continuous liquid phase and four bubble size groups using mechanistic closure models for the ensemble-averaged Navier-Stokes equations. Mechanistic models for the drag and non-drag interfacial forces are implemented to include the governing physics to describe the hydrodynamic forces controlling the gas distribution. The closure models provide the functional form of the interfacial forces, with user defined coefficients to adjust the force magnitude. An optimization strategy was devised for these coefficients using commercial design optimization software. This paper demonstrates an approach to optimizing CMFD model parameters using a design optimization approach. Computed radial void fraction profiles predicted by the NPHASE-CMFD code are compared to experimental data for four bubble size groups.

Donna Post Guillen

2009-07-01T23:59:59.000Z

122

Regional Dynamics Model (REDYN) | Open Energy Information  

Open Energy Info (EERE)

Regional Dynamics Model (REDYN) Regional Dynamics Model (REDYN) Jump to: navigation, search Tool Summary Name: REDYN Agency/Company /Organization: Regional Dynamics Inc. Sector: Energy Phase: Determine Baseline, "Evaluate Options and Determine Feasibility" is not in the list of possible values (Bring the Right People Together, Create a Vision, Determine Baseline, Evaluate Options, Develop Goals, Prepare a Plan, Get Feedback, Develop Finance and Implement Projects, Create Early Successes, Evaluate Effectiveness and Revise as Needed) for this property., Develop Goals Topics: Market analysis, Policies/deployment programs, Co-benefits assessment, - Macroeconomic Resource Type: Software/modeling tools User Interface: Desktop Application Website: www.regionaldynamics.com/

123

A Simple Distributed Particle Swarm Optimization for Dynamic and Noisy Environments  

SciTech Connect

In this paper, we present a Simple Distributed Particle Swarm Optimization (SDPSO) algorithm that can be used to track the optimal solution in a dynamic and noisy environment. The classic PSO algorithm lacks the ability to track changing optimum in a dynamic environment. Several approaches have been investigated to enhance the PSO algorithm s ability in dynamic environments. However, in dealing with dynamic environments, these approaches have lost PSO s original strengths of decentralized control and ease of implementation. The SDPSO algorithm proposed in this paper maintains these classic PSO features as well as provides the optimum result tracking capability in dynamic environments. In this research, the DF1 multimodal dynamic environment generator proposed by Morrison and De Jong is used to evaluate the classic PSO, SDPSO and other two adaptive PSOs.

Cui, Xiaohui [ORNL; Potok, Thomas E [ORNL

2009-01-01T23:59:59.000Z

124

Nonlinear regression model generation using hyperparameter optimization  

Science Conference Proceedings (OSTI)

An algorithm of the inductive model generation and model selection is proposed to solve the problem of automatic construction of regression models. A regression model is an admissible superposition of smooth functions given by experts. Coherent Bayesian ... Keywords: Coherent Bayesian inference, Hyperparameters, Model generation, Model selection, Regression

Vadim Strijov; Gerhard Wilhelm Weber

2010-08-01T23:59:59.000Z

125

Assessing FPAR Source and Parameter Optimization Scheme in Application of a Diagnostic Carbon Flux Model  

Science Conference Proceedings (OSTI)

The combination of satellite remote sensing and carbon cycle models provides an opportunity for regional to global scale monitoring of terrestrial gross primary production, ecosystem respiration, and net ecosystem production. FPAR (the fraction of photosynthetically active radiation absorbed by the plant canopy) is a critical input to diagnostic models, however little is known about the relative effectiveness of FPAR products from different satellite sensors nor about the sensitivity of flux estimates to different parameterization approaches. In this study, we used multiyear observations of carbon flux at four eddy covariance flux tower sites within the conifer biome to evaluate these factors. FPAR products from the MODIS and SeaWiFS sensors, and the effects of single site vs. cross-site parameter optimization were tested with the CFLUX model. The SeaWiFs FPAR product showed greater dynamic range across sites and resulted in slightly reduced flux estimation errors relative to the MODIS product when using cross-site optimization. With site-specific parameter optimization, the flux model was effective in capturing seasonal and interannual variation in the carbon fluxes at these sites. The cross-site prediction errors were lower when using parameters from a cross-site optimization compared to parameter sets from optimization at single sites. These results support the practice of multisite optimization within a biome for parameterization of diagnostic carbon flux models.

Turner, D P; Ritts, W D; Wharton, S; Thomas, C; Monson, R; Black, T A

2009-02-26T23:59:59.000Z

126

Optimization model based on genetic algorithms for oil wells  

Science Conference Proceedings (OSTI)

The Processes of optimization of oil wells involve an objective function that maximizes the commercial price and minimizes the production cost. For the solution of this type of problem, in the last decade the evolutionary technologies have demonstrated ... Keywords: evolutionary computation, model of production of well, problem of optimization, wells by artificial gas lift

Edgar Camargo; José Aguilar; Addison Ríos; Francklin Rivas; Joseph Aguilar-Martin

2010-12-01T23:59:59.000Z

127

On Frontal Dynamics in Two Model Oceans  

Science Conference Proceedings (OSTI)

Vertically homogeneous variable-temperature layer models are often used to describe upper-ocean variability, the dynamics of jets and fronts included. Frontogenesis is known to have a preference for strong cyclonic shears. When a frontal wave ...

Tor Eldevik

2002-10-01T23:59:59.000Z

128

A Dynamical Systems Model for Language Change  

E-Print Network (OSTI)

Formalizing linguists' intuitions of language change as a dynamical system, we quantify the time course of language change including sudden vs. gradual changes in languages. We apply the computer model to the historical ...

Niyogi, Partha

1995-12-01T23:59:59.000Z

129

Short-Term Dynamics of Model Errors  

Science Conference Proceedings (OSTI)

The natural instability of the atmosphere is at the origin of the rapid amplification of errors coming from the uncertainty on the initial conditions and from the imperfect representation (the model) of the atmospheric dynamics. In this paper, ...

S. Vannitsem; Z. Toth

2002-09-01T23:59:59.000Z

130

Modelling the dynamical baroreflex-feedback control  

Science Conference Proceedings (OSTI)

A comprehensive model of the baroreflex-feedback mechanism regulating the heart rate, the contractility of the ventricle and the peripheral vascular resistance is presented. The dynamics of the affector and the effector parts are modelled. For each of ... Keywords: Baroreceptor, Cardiovascular system, Mathematical modelling, Medical applications, Neural biology, Nonlinear feedback mechanism, Nonlinear oscillations

J. T. Ottesen

2000-02-01T23:59:59.000Z

131

Social impact models of opinion dynamics  

E-Print Network (OSTI)

We investigate models of opinion formation which are based on the social impact theory. The following approaches are discussed: (i) general mean field theory of social impact, (ii) a social impact model with learning, (iii) a model of a finite group with a strong leader, (iv) a social impact model with dynamically changing social temperature, (v) a model with individuals treated as active Brownian particles interacting via a communication field. 1

Janusz A. Ho?lyst; Krzysztof Kacperski; Frank Schweitzer; Janusz A. Ho?lyst; Krzysztof Kacperski; Frank Schweitzer

2001-01-01T23:59:59.000Z

132

Optimal pulse control of dynamic systems in the shock phase  

Science Conference Proceedings (OSTI)

For minimization and maximization of the kinetic energy of a body hitting a fixed visco-elastic obstacle with the energy calculated at the instant of body detachment from the obstacle, the optimal control laws in the impact phase were obtained.

A. A. Galyaev

2006-01-01T23:59:59.000Z

133

Swarm Intelligence for Urban Dynamics Modelling  

Science Conference Proceedings (OSTI)

In this paper, we propose swarm intelligence algorithms to deal with dynamical and spatial organization emergence. The goal is to model and simulate the developement of spatial centers using multi-criteria. We combine a decentralized approach based on emergent clustering mixed with spatial constraints or attractions. We propose an extension of the ant nest building algorithm with multi-center and adaptive process. Typically, this model is suitable to analyse and simulate urban dynamics like gentrification or the dynamics of the cultural equipment in urban area.

Ghnemat, Rawan; Bertelle, Cyrille [LITIS-University of Le Havre 25 rue Philippe Lebon-BP 540 76058 Le Havre cedex (France); Duchamp, Gerard H. E. [LIPN-University of Paris XIII 99 avenue Jean-Baptiste Clement 93430 Villetaneuse (France)

2009-04-16T23:59:59.000Z

134

INDDGO: Integrated Network Decomposition & Dynamic programming for Graph Optimization  

SciTech Connect

It is well-known that dynamic programming algorithms can utilize tree decompositions to provide a way to solve some \\emph{NP}-hard problems on graphs where the complexity is polynomial in the number of nodes and edges in the graph, but exponential in the width of the underlying tree decomposition. However, there has been relatively little computational work done to determine the practical utility of such dynamic programming algorithms. We have developed software to construct tree decompositions using various heuristics and have created a fast, memory-efficient dynamic programming implementation for solving maximum weighted independent set. We describe our software and the algorithms we have implemented, focusing on memory saving techniques for the dynamic programming. We compare the running time and memory usage of our implementation with other techniques for solving maximum weighted independent set, including a commercial integer programming solver and a semi-definite programming solver. Our results indicate that it is possible to solve some instances where the underlying decomposition has width much larger than suggested by the literature. For certain types of problems, our dynamic programming code runs several times faster than these other methods.

Groer, Christopher S [ORNL; Sullivan, Blair D [ORNL; Weerapurage, Dinesh P [ORNL

2012-10-01T23:59:59.000Z

135

Modeling and Optimizing the Thermal Stress Distribution in a ...  

Science Conference Proceedings (OSTI)

Conference Tools for Materials Science & Technology 2012 ... Presentation Title, Modeling and Optimizing the Thermal Stress Distribution in a Plasma Spray System for ... and analyzed for an applied thermal load in COMSOL® Multiphysics®.

136

Optimal Perturbations in the Eady Model: Resonance versus PV Unshielding  

Science Conference Proceedings (OSTI)

Using a nonmodal decomposition technique based on the potential vorticity (PV) perspective, the optimal perturbation or singular vector (SV) of the Eady model without upper rigid lid is studied for a kinetic energy norm. Special emphasis is put ...

H. de Vries; J. D. Opsteegh

2005-02-01T23:59:59.000Z

137

Optimizing Parameters in an Atmospheric General Circulation Model  

Science Conference Proceedings (OSTI)

An efficient method to optimize the parameter values of the subgrid parameterizations of an atmospheric general circulation model is described. The method is based on the downhill simplex minimization of a cost function computed from the ...

C. A. Severijns; W. Hazeleger

2005-09-01T23:59:59.000Z

138

Optimal Forcing Patterns for Coupled Models of ENSO  

Science Conference Proceedings (OSTI)

The optimal forcing patterns for El Niño–Southern Oscillation (ENSO) are examined for a hierarchy of hybrid coupled models using generalized stability theory. Specifically two cases are considered: one where the forcing is stochastic in time, and ...

Andrew M. Moore; Javier Zavala-Garay; Youmin Tang; Richard Kleeman; Anthony T. Weaver; Jérôme Vialard; Kamran Sahami; David L. T. Anderson; Michael Fisher

2006-09-01T23:59:59.000Z

139

Dynamic Model of Facial Cooling  

Science Conference Proceedings (OSTI)

Recent modifications to windchill forecasting have motivated the development of a rate-of-tissue-cooling model for the purpose of predicting facial cooling times. The model assumes a hollow cylindrical geometry with a fixed internal boundary ...

Peter Tikuisis; Randall J. Osczevski

2002-12-01T23:59:59.000Z

140

Dynamics of a fishing model  

Science Conference Proceedings (OSTI)

In this paper, the authors give sufficient conditions for the existence and global attractivity of a positive periodic solution of the first order nonlinear differential equation N?(t) = -a(t)N(t) +b(t) N(t)/1+(N(t)/p(t))? ... Keywords: attractivity, fishing model, periodic solution, population model

John R. Graef; Seshadev Padhi; Shilpee Srivastava

2010-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamic optimization model" 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

Framework combining static optimization, dynamic scheduling and decision analysis applicable to complex primary HVAC&R systems.  

E-Print Network (OSTI)

??The primary objective of this work is to propose a general and computationally efficient methodology for dynamic scheduling and optimal control of primary HVAC&R systems… (more)

Jiang, Wei

2006-01-01T23:59:59.000Z

142

Gas permeation carbon capture --- Process modeling and optimization  

SciTech Connect

A multi-staged gas permeation carbon capture process model was developed in Aspen Custom Modeler{reg_sign} (ACM) and optimized in the context of the retrofit of a 550 MW subcritical pulverized coal (PC) power plant. The gas permeation stages in the process are described by a custom multi-component, hollowfiber membrane model. Gas transport across the asymmetric membrane was modeled according to the solution-diffusion model for the selective skin layer and the assumption of negligible flux resistance by the porous support. Counter-current, one-dimensional plug flow was assumed with permeate pressure drop in the fiber lumen side due to capillary constrained flow. A modular optimization framework was used to minimize the levelized cost of electricity (LCOE) by optimizing a set of key process variables. The framework allows the external control of multiple simulation modules from different software packages from a common interface.

Morinelly, Juan; Miller, David

2011-01-01T23:59:59.000Z

143

New Models Help Optimize Development of Bakken Shale Resources | Department  

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

Models Help Optimize Development of Bakken Shale Resources Models Help Optimize Development of Bakken Shale Resources New Models Help Optimize Development of Bakken Shale Resources February 7, 2012 - 12:00pm Addthis Washington, DC - Exploration and field development in the largest continuous oil play in the lower 48 states, located in North Dakota and eastern Montana, will be guided by new geo-models developed with funding from the Department of Energy's (DOE) Office of Fossil Energy (FE). The three-year project to develop exploration and reservoir models for the Bakken Shale resource play was conducted by the Colorado School of Mines (CSM), through research funded by FE's Oil and Natural Gas Program. A "play" is a shale formation containing significant accumulations of natural gas or oil. The U.S. Geological Survey estimates the Bakken Shale

144

New Models Help Optimize Development of Bakken Shale Resources | Department  

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

New Models Help Optimize Development of Bakken Shale Resources New Models Help Optimize Development of Bakken Shale Resources New Models Help Optimize Development of Bakken Shale Resources February 7, 2012 - 12:00pm Addthis Washington, DC - Exploration and field development in the largest continuous oil play in the lower 48 states, located in North Dakota and eastern Montana, will be guided by new geo-models developed with funding from the Department of Energy's (DOE) Office of Fossil Energy (FE). The three-year project to develop exploration and reservoir models for the Bakken Shale resource play was conducted by the Colorado School of Mines (CSM), through research funded by FE's Oil and Natural Gas Program. A "play" is a shale formation containing significant accumulations of natural gas or oil. The U.S. Geological Survey estimates the Bakken Shale

145

Optimal aggregation of linear time series models  

Science Conference Proceedings (OSTI)

Aggregation is a central and mainly unsolved problem in econometrics. When considering linear time series models, a widely used method is to replace the disaggregate model by an aggregative one in which the variables are grouped and replaced by sums ... Keywords: Aggregation, Industrial classification, Threshold accepting

J. Chipman; P. Winker

2005-04-01T23:59:59.000Z

146

Optimal Accuracy in Semi-Lagrangian Models  

Science Conference Proceedings (OSTI)

A one-dimensional semi-implicit semi-Lagrangian (SISL) linear model and a nonlinear SISL global shallow-water model are employed to investigate the sensitivity of the solutions on (i) the order of interpolation applied at the departure points, (...

Fredrick H. M. Semazzi; Paul Dekker

1994-09-01T23:59:59.000Z

147

Vehicle Transient Air Conditioning Analysis: Model Development& System Optimization Investigations  

DOE Green Energy (OSTI)

The National Renewable Energy Laboratory (NREL) has developed a transient air conditioning (A/C) system model using SINDA/FLUINT analysis software. It captures all the relevant physics of transient A/C system performance, including two-phase flow effects in the evaporator and condenser, system mass effects, air side heat transfer on the condenser/evaporator, vehicle speed effects, temperature-dependent properties, and integration with a simplified cabin thermal model. It has demonstrated robust and powerful system design optimization capabilities. Single-variable and multiple variable design optimizations have been performed and are presented. Various system performance parameters can be optimized, including system COP, cabin cool-down time, and system heat load capacity. This work presents this new transient A/C system analysis and optimization tool and shows some high-level system design conclusions reached to date. The work focuses on R-134a A/C systems, but future efforts will modify the model to investigate the transient performance of alternative refrigerant systems such as carbon dioxide systems. NREL is integrating its transient air conditioning model into NRELs ADVISOR vehicle system analysis software, with the objective of simultaneously optimizing A/C system designs within the overall vehicle design optimization.

Hendricks, T. J.

2001-06-01T23:59:59.000Z

148

doi:10.1155/2012/769702 Review Article Modeling of Biological Intelligence for SCM System Optimization  

E-Print Network (OSTI)

License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. This article summarizes some methods from biological intelligence for modeling and optimization of supply chain management (SCM) systems, including genetic algorithms, evolutionary programming, differential evolution, swarm intelligence, artificial immune, and other biological intelligence related methods. An SCM system is adaptive, dynamic, open self-organizing, which is maintained by flows of information, materials, goods, funds, and energy. Traditional methods for modeling and optimizing complex SCM systems require huge amounts of computing resources, and biological intelligence-based solutions can often provide valuable alternatives for efficiently solving problems. The paper summarizes the recent related methods for the design and optimization of SCM systems, which covers the most widely used genetic algorithms and other evolutionary algorithms. 1.

Shengyong Chen; Yujun Zheng; Carlo Cattani; Wanliang Wang

2011-01-01T23:59:59.000Z

149

NETL: Gasification Systems - Model Based Optimal Sensor Network Design for  

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

Model Based Optimal Sensor Network Design for Condition Monitoring Model Based Optimal Sensor Network Design for Condition Monitoring Project Number: FE0005712 General Electric (GE) Global Research is developing an advanced model-based optimal sensor network to monitor the condition of the gasification section in an integrated gasification combined cycle (IGCC) plant. The work builds on model-based controls aimed at enhancing efficiency and operational flexibility through increased automation. Within an overall strategy of employing model-based online monitoring and predictive controls, GE Global Research is extending existing models for the gasifier and radiant syngas cooler to include the effects of degradation and fouling on the sensed variables like temperature etc., and will implement an estimation algorithm to assess the extent of gasifier refractory degradation and radiant syngas cooler fouling. An optimization-based solution will be employed to optimally place the hardware sensors utilized in the estimation algorithm in order to achieve the monitoring requirements at the lowest cost. The performance of the sensor placement algorithm and resulting monitoring solution will be demonstrated through simulations using representative test cases. The overall approach is one of the first to be applicable to condition monitoring of critical components in IGCC plants.

150

Optimal Dynamic Strategy of Building a Hydrogen Infrastructure in Beijing  

E-Print Network (OSTI)

Hydrogen Distribution Infrastructure, American Institute ofa Hydrogen Energy Infrastructure." Annual Review of EnergyJoan (2003). Modeling Infrastructure for a Fossil Hydrogen

Lin, Zhenhong; Ogden, Joan M; Fan, Yueyue; Sperling, Dan

2005-01-01T23:59:59.000Z

151

Finding Benefits by Modeling and Optimizing Steam and Power Systems  

E-Print Network (OSTI)

A site-wide steam modeling and optimization program (Visual MESA) was implemented at the INEOS Chocolate Bayou site. This program optimizes steam production, compressor turbine extraction, pump operation (turbine/motor) operation, as well as the monitoring of the entire steam system. This is used for both day-to-day site optimization as well as long-term site planning. In this presentation, we will discuss who the main users of the program are and how they and the plant derive benefits from its use.

Jones, B.; Nelson, D.

2007-01-01T23:59:59.000Z

152

Global and Convex Optimization in Modeling Environments ...  

E-Print Network (OSTI)

Aug 12, 2002 ... This model is a frequently used classical GO test ..... The results are automatically written to a summary and a detailed report file. ..... radiated acoustic power, delivered to the radiation resistance Rr, to input electric power.

153

Infrared Radiance Modeling by Optimal Spectral Sampling  

Science Conference Proceedings (OSTI)

This paper describes a rapid and accurate technique for the numerical modeling of band transmittances and radiances in media with nonhomogeneous thermodynamic properties (i.e., temperature and pressure), containing a mixture of absorbing gases ...

Jean-Luc Moncet; Gennady Uymin; Alan E. Lipton; Hilary E. Snell

2008-12-01T23:59:59.000Z

154

An integrated model for optimizing weld quality  

SciTech Connect

Welding has evolved in the last few decades from almost an empirical art to an activity embodying the most advanced tools of, various basic and applied sciences. Significant progress has been made in understanding the welding process and welded materials. The improved knowledge base has been useful in automation and process control. In view of the large number of variables involved, creating an adequately large database to understand and control the welding process is expensive and time consuming, if not impractical. A recourse is to simulate welding processes through a set of mathematical equations representing the essential physical processes of welding. Results obtained from the phenomenological models depend crucially on the quality of the physical relations in the models and the trustworthiness of input data. In this paper, recent advances in the mathematical modeling of fundamental phenomena in welds are summarized. State of the art mathematical models, advances in computational techniques, emerging high performance computers, and experimental validation techniques have provided significant insight into the fundamental factors that control the development of the weldment. Current status and scientific issues in heat and fluid flow in welds, heat source metal interaction, and solidification microstructure are assessed. Future research areas of major importance for understanding the fundamental phenomena in weld behavior are identified.

Zacharia, T.; Radhakrishnan, B. [Oak Ridge National Lab., TN (United States); Paul, A.J.; Cheng, C. [Concurrent Technologies Corp., Johnstown, PA (United States)

1995-06-01T23:59:59.000Z

155

Research on water level optimal control of boiler drum based on dual heuristic dynamic programming  

Science Conference Proceedings (OSTI)

Boiler drum system is an important component of a thermal power plant or industrial production, and the water level is a critical parameter of boiler drum control system. Because of non-linear, strong coupling and large disturbance, it is difficult to ... Keywords: BP neural network, boiler drum level, dual heuristic dynamic programming, optimal control

Qingbao Huang; Shaojian Song; Xiaofeng Lin; Kui Peng

2011-05-01T23:59:59.000Z

156

Dynamic architecture for solving optimization problems of operators of mobile telephony  

Science Conference Proceedings (OSTI)

The operators of the mobile telephony are more and more demanding towards their applications. They wait for a big reliability, for a number ceaselessly increasing of services, the respect for the constraints of conviviality, for cost, etc. Therefore, ... Keywords: GSM, algebra of process, cellular networks, dynamic optimization, multi agents systems

Chaker Mezioud; Mohammed Khireddine Kholladi

2009-06-01T23:59:59.000Z

157

Near-Optimal, Dynamic Module Reconfiguration in a Photovoltaic System to Combat Partial Shading Effects  

E-Print Network (OSTI)

Near-Optimal, Dynamic Module Reconfiguration in a Photovoltaic System to Combat Partial Shading}@elpl.snu.ac.kr, pedram@usc.edu ABSTRACT Partial shading is a serious obstacle to effective utilization of photovoltaic-parallel connected cells. This paper presents modified PV cell structures with integrated switches, imbalanced cell

Pedram, Massoud

158

A systems approach in examining optimization opportunities and dynamics of the global steel industry  

Science Conference Proceedings (OSTI)

This paper takes a systems perspective in exploring and analyzing optimization possibilities and market dynamics of the global steel industry. To assess and improve this industry's performance, two analytical approaches are used. First, a multiple regression ... Keywords: China, Co-opetition, Nash equilibrium, Porter, SWOT analysis, Steel industry, exports, forecasts, game theory, imports, multiple regression analysis, production, systems management strategies, systems thinking

Sameer Kumar; Nidhi Ghildayal; Cheryl Ostor

2008-12-01T23:59:59.000Z

159

Particle Swarm Optimization of Ceramic Roller Kiln Temperature Field Uniformity Using Computational Fluid Dynamics Tools  

Science Conference Proceedings (OSTI)

In this paper ceramic roller kiln temperature field uniformity is mainly researched using computational fluid dynamics tools and particle swarm optimization (PSO). In consideration of burning and burning temperature control is key technique of burning ... Keywords: PSO, temperature field uniformity, multiple liner regression, uniform design, ceramic roller kiln design

Wenbi Rao; Peng Li

2009-06-01T23:59:59.000Z

160

Optimal wire sizing and buffer insertion for low power and a generalized delay model  

Science Conference Proceedings (OSTI)

We present efficient, optimal algorithms for timing optimization by discrete wire sizing and buffer insertion. Our algorithms are able to minimize dynamic power dissipation subject to given timing constraints. In addition, we compute the complete power-delay ... Keywords: Timing Optization, Elmore Delay, Dynamic Power Dissipation, Dynamic Programming, Signal Slew

John Lillis; Chung-Kuan Cheng; Ting-Ting Y. Lin

1995-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamic optimization model" 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

Modeling and Optimization of a Bioethanol Production Facility  

E-Print Network (OSTI)

The primary objective of this work is to identify the optimal bioethanol production plant capacity and configuration based on currently available technology for all the processing sections involved. To effect this study, a systematic method is utilized which involves the development of a superstructure for the overall technology selection, process simulation and model regression of each processing step as well as equipment costing and overall economic evaluation. The developed optimization model is also designed to incorporate various biomass feedstocks as well as realistic maximum equipment sizing thereby ensuring pragmatism of the work. For this study, the criterion for optimization is minimum ethanol price. The secondary and more interesting aim of this work was to develop a systematic method for evaluating the economics of biomass storage due to seasonal availabilities. In essence, a mathematical model was developed to link seasonal availabilities with plant capacity with subsequent integration into the original model developed. Similarly, the criterion for optimization is minimum ethanol price. The results of this work reveal that the optimal bioethanol production plant capacity is ~2800 MT biomass/day utilizing Ammonia Fiber Explosion pretreatment technology and corn stover as the preferred biomass feedstock. This configuration provides a minimum ethanol price of $1.96/gal. Results also show that this optimal pretreatment choice has a relatively high sensitivity to chemical cost thereby increasing the risk of implementation. Secondary to this optimal selection was lime pretreatment using switchgrass which showed a fairly stable sensitivity to market chemical cost. For the storage economics evaluation, results indicated that biomass storage is not economical beyond a plant capacity of ~98 MMgal/yr with an average biomass shortage period of 3 months. The study also showed that for storage to be economical at all plant capacities, the storage scheme employed should be general open air land use with a corresponding biomass loss rate as defined in the study of 0.5 percent per month.

Gabriel, Kerron Jude

2011-08-01T23:59:59.000Z

162

Brief Equivalence of hybrid dynamical models  

Science Conference Proceedings (OSTI)

This paper establishes equivalences among five classes of hybrid systems: mixed logical dynamical (MLD) systems, linear complementarity (LC) systems, extended linear complementarity (ELC) systems, piecewise affine (PWA) systems, and max-min-plus-scaling ... Keywords: Equivalent models, Hybrid systems, Piecewise affine systems

W. P. M. H. Heemels; B. De Schutter; A. Bemporad

2001-07-01T23:59:59.000Z

163

Modeling of Reactor Kinetics and Dynamics  

SciTech Connect

In order to model a full fuel cycle in a nuclear reactor, it is necessary to simulate the short time-scale kinetic behavior of the reactor as well as the long time-scale dynamics that occur with fuel burnup. The former is modeled using the point kinetics equations, while the latter is modeled by coupling fuel burnup equations with the kinetics equations. When the equations are solved simultaneously with a nonlinear equation solver, the end result is a code with the unique capability of modeling transients at any time during a fuel cycle.

Matthew Johnson; Scott Lucas; Pavel Tsvetkov

2010-09-01T23:59:59.000Z

164

Using system dynamics for simulation and optimization of one coal industry system under fuzzy environment  

Science Conference Proceedings (OSTI)

In this paper, we have developed a model that integrates system dynamics with fuzzy multiple objective programming (SD-FMOP). This model can be used to study the complex interactions in a industry system. In the process of confirming sensitive parameters ... Keywords: Coal industry planning, Fuzzy set theory, Multiple objective programming, Simulation, System dynamics

Jiuping Xu; Xiaofei Li

2011-09-01T23:59:59.000Z

165

Dynamic Decision Making for Graphical Models Applied to Oil Exploration  

E-Print Network (OSTI)

We present a framework for sequential decision making in problems described by graphical models. The setting is given by dependent discrete random variables with associated costs or revenues. In our examples, the dependent variables are the potential outcomes (oil, gas or dry) when drilling a petroleum well. The goal is to develop an optimal selection strategy that incorporates a chosen utility function within an approximated dynamic programming scheme. We propose and compare different approximations, from simple heuristics to more complex iterative schemes, and we discuss their computational properties. We apply our strategies to oil exploration over multiple prospects modeled by a directed acyclic graph, and to a reservoir drilling decision problem modeled by a Markov random field. The results show that the suggested strategies clearly improve the simpler intuitive constructions, and this is useful when selecting exploration policies.

Martinelli, Gabriele; Hauge, Ragnar

2012-01-01T23:59:59.000Z

166

Adaptive Optimization and Systematic Probing of Infrastructure System Maintenance Policies under Model Uncertainty  

E-Print Network (OSTI)

Maintenance; Optimization; Probabilistic models; Adaptive systems; Uncertainty principles . Introduction Infrastructure management systems

Madanat, S M; Park, Sejung; Kuhn, K D

2006-01-01T23:59:59.000Z

167

Feature extraction for structural dynamics model validation  

SciTech Connect

This study focuses on defining and comparing response features that can be used for structural dynamics model validation studies. Features extracted from dynamic responses obtained analytically or experimentally, such as basic signal statistics, frequency spectra, and estimated time-series models, can be used to compare characteristics of structural system dynamics. By comparing those response features extracted from experimental data and numerical outputs, validation and uncertainty quantification of numerical model containing uncertain parameters can be realized. In this study, the applicability of some response features to model validation is first discussed using measured data from a simple test-bed structure and the associated numerical simulations of these experiments. issues that must be considered were sensitivity, dimensionality, type of response, and presence or absence of measurement noise in the response. Furthermore, we illustrate a comparison method of multivariate feature vectors for statistical model validation. Results show that the outlier detection technique using the Mahalanobis distance metric can be used as an effective and quantifiable technique for selecting appropriate model parameters. However, in this process, one must not only consider the sensitivity of the features being used, but also correlation of the parameters being compared.

Hemez, Francois [Los Alamos National Laboratory; Farrar, Charles [Los Alamos National Laboratory; Park, Gyuhae [Los Alamos National Laboratory; Nishio, Mayuko [UNIV OF TOKYO; Worden, Keith [UNIV OF SHEFFIELD; Takeda, Nobuo [UNIV OF TOKYO

2010-11-08T23:59:59.000Z

168

GRAVITATIONAL LENS MODELING WITH GENETIC ALGORITHMS AND PARTICLE SWARM OPTIMIZERS  

Science Conference Proceedings (OSTI)

Strong gravitational lensing of an extended object is described by a mapping from source to image coordinates that is nonlinear and cannot generally be inverted analytically. Determining the structure of the source intensity distribution also requires a description of the blurring effect due to a point-spread function. This initial study uses an iterative gravitational lens modeling scheme based on the semilinear method to determine the linear parameters (source intensity profile) of a strongly lensed system. Our 'matrix-free' approach avoids construction of the lens and blurring operators while retaining the least-squares formulation of the problem. The parameters of an analytical lens model are found through nonlinear optimization by an advanced genetic algorithm (GA) and particle swarm optimizer (PSO). These global optimization routines are designed to explore the parameter space thoroughly, mapping model degeneracies in detail. We develop a novel method that determines the L-curve for each solution automatically, which represents the trade-off between the image {chi}{sup 2} and regularization effects, and allows an estimate of the optimally regularized solution for each lens parameter set. In the final step of the optimization procedure, the lens model with the lowest {chi}{sup 2} is used while the global optimizer solves for the source intensity distribution directly. This allows us to accurately determine the number of degrees of freedom in the problem to facilitate comparison between lens models and enforce positivity on the source profile. In practice, we find that the GA conducts a more thorough search of the parameter space than the PSO.

Rogers, Adam; Fiege, Jason D. [Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T-2N2 (Canada)

2011-02-01T23:59:59.000Z

169

Stochastic dynamic optimization of consumption and the induced price elasticity of demand in smart grids  

E-Print Network (OSTI)

This thesis presents a mathematical model of consumer behavior in response to stochastically-varying electricity prices, and a characterization of price-elasticity of demand created by optimal utilization of storage and ...

Faghih, Ali

2011-01-01T23:59:59.000Z

170

INVENTORY DYNAMICS IMPLEMENTATION TO A NETWORK DESIGN MODEL Format Review.  

E-Print Network (OSTI)

??This research presents an inventory dynamics model that is implemented into an already existing supply chain footprint model for a multinational manufacturing company. The model… (more)

Better Romero, Miguel

2009-01-01T23:59:59.000Z

171

Optimal reinsurance/investment problems for general insurance models  

E-Print Network (OSTI)

In this paper the utility optimization problem for a general insurance model is studied. The reserve process of the insurance company is described by a stochastic differential equation driven by a Brownian motion and a Poisson random measure, representing the randomness from the financial market and the insurance claims, respectively. The random safety loading and stochastic interest rates are allowed in the model so that the reserve process is non-Markovian in general. The insurance company can manage the reserves through both portfolios of the investment and a reinsurance policy to optimize a certain utility function, defined in a generic way. The main feature of the problem lies in the intrinsic constraint on the part of reinsurance policy, which is only proportional to the claim-size instead of the current level of reserve, and hence it is quite different from the optimal investment/consumption problem with constraints in finance. Necessary and sufficient conditions for both well posedness and solvability...

Liu, Yuping; 10.1214/08-AAP582

2009-01-01T23:59:59.000Z

172

Extended Lagrangian Born-Oppenheimer molecular dynamics in the limit of vanishing self-consistent field optimization  

E-Print Network (OSTI)

We present an efficient general approach to first principles molecular dynamics simulations based on extended Lagrangian Born-Oppenheimer molecular dynamics in the limit of vanishing self-consistent field optimization. The reduction of the optimization requirement reduces the computational cost to a minimum, but without causing any significant loss of accuracy or longterm energy drift. The optimization-free first principles molecular dynamics requires only one single diagonalization per time step and yields trajectories at the same level of accuracy as "exact", fully converged, Born-Oppenheimer molecular dynamics simulations. The optimization-free limit of extended Lagrangian Born-Oppenheimer molecular dynamics therefore represents an ideal starting point for a robust and efficient formulation of a new generation first principles quantum mechanical molecular dynamics simulation schemes.

Souvatzis, Petros

2013-01-01T23:59:59.000Z

173

A Model to Optimize Green Energy Supply Chain  

Science Conference Proceedings (OSTI)

Bioenergy is renewable energy derived from biological sources, to be used for production of heat, electricity and transportation fuels. The collection of biomass is a logistic process from different source locations to energy plants. The biomass-to-energy ... Keywords: supply chain, green, optimize, model

Na Liu

2012-10-01T23:59:59.000Z

174

A stochastic control model for optimal timing of climate policies  

Science Conference Proceedings (OSTI)

A stochastic control model is proposed as a paradigm for the design of optimal timing of greenhouse gas (GHG) emission abatement. The resolution of uncertainty concerning climate sensitivity and the technological breakthrough providing access to a carbon-free ... Keywords: Climate policies, Environmental hedging strategies, Piecewise deterministic Markov process, Stochastic control

O. Bahn; A. Haurie; R. Malhamé

2008-06-01T23:59:59.000Z

175

Metaheuristics for strain optimization using transcriptional information enriched metabolic models  

Science Conference Proceedings (OSTI)

The identification of a set of genetic manipulations that result in a microbial strain with improved production capabilities of a metabolite with industrial interest is a big challenge in Metabolic Engineering. Evolutionary Algorithms and Simulated Annealing ... Keywords: flux-balance analysis, metabolic engineering, set based representations, strain optimization, transcriptional models

Paulo Vilaça; Paulo Maia; Isabel Rocha; Miguel Rocha

2010-04-01T23:59:59.000Z

176

Adaptive Optimization and Systematic Probing of Infrastructure System Maintenance Policies under Model Uncertainty  

E-Print Network (OSTI)

maintenance and repair policies in infrastructure managementOptimal maintenance decisions for pavement management. ” J.Maintenance; Optimization; Probabilistic models; Adaptive systems; Uncertainty principles . Introduction Infrastructure management

Madanat, S M; Park, Sejung; Kuhn, K D

2006-01-01T23:59:59.000Z

177

CPOPT : optimization for fitting CANDECOMP/PARAFAC models.  

Science Conference Proceedings (OSTI)

Tensor decompositions (e.g., higher-order analogues of matrix decompositions) are powerful tools for data analysis. In particular, the CANDECOMP/PARAFAC (CP) model has proved useful in many applications such chemometrics, signal processing, and web analysis; see for details. The problem of computing the CP decomposition is typically solved using an alternating least squares (ALS) approach. We discuss the use of optimization-based algorithms for CP, including how to efficiently compute the derivatives necessary for the optimization methods. Numerical studies highlight the positive features of our CPOPT algorithms, as compared with ALS and Gauss-Newton approaches.

Dunlavy, Daniel M.; Kolda, Tamara Gibson; Acar, Evrim

2008-10-01T23:59:59.000Z

178

Empirical Correction of a Dynamical Model. Part I: Fundamental Issues  

Science Conference Proceedings (OSTI)

The possibility of empirically correcting a nonlinear dynamical model is examined. The empirical correction is constructed by fitting a first-order Markov model to the forecast errors using initial conditions as predictors. The dynamical operator ...

Timothy DelSole; Arthur Y. Hou

1999-11-01T23:59:59.000Z

179

Performance monitoring for new phase dynamic optimization of instruction dispatch cluster configuration  

DOE Patents (OSTI)

In a processor having multiple clusters which operate in parallel, the number of clusters in use can be varied dynamically. At the start of each program phase, the configuration option for an interval is run to determine the optimal configuration, which is used until the next phase change is detected. The optimum instruction interval is determined by starting with a minimum interval and doubling it until a low stability factor is reached.

Balasubramonian, Rajeev (Sandy, UT); Dwarkadas, Sandhya (Rochester, NY); Albonesi, David (Ithaca, NY)

2012-01-24T23:59:59.000Z

180

Optimal Control of the Solid Fuel Ignition Model with H1-Cost  

Science Conference Proceedings (OSTI)

Optimal control problems for the stationary as well as the time-dependent solid fuel ignition model are investigated. Existence of optimal controls is proved, and optimality systems are derived. The analysis is based on a closedness lemma for the exponential ... Keywords: control of exponential nonlinearity, explosion phenomena, optimal control, optimality conditions

Kazufumi Ito; Karl Kunisch

2001-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamic optimization model" 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

Non-causal models in long term planning via set contractive optimal control methods  

Science Conference Proceedings (OSTI)

The notion of consistency for optimal plans introduced in [F.E. Kydland, E.C. Prescott, Rules rather than decisions: The inconsistency of optimal plans, J. Polit. Econ. 85 (3) (1977) 473-491] is studied in relation to dynamic programming and to multi-objective ... Keywords: Balance set, Long term optimal planning, Pareto solutions

E. A. Galperin; I. Galperin

2007-06-01T23:59:59.000Z

182

Dynamical model for Pion - Nucleon Bremsstrahlung  

E-Print Network (OSTI)

A dynamical model based on effective Lagrangians is proposed to describe the bremsstrahlung reaction $ \\pi N \\to \\pi N \\gamma$ at low energies. The $\\Delta(1232)$ degrees of freedom are incorporated in a way consistent with both, electromagnetic gauge invariance and invariance under contact transformations. The model also includes the initial and final state rescattering of hadrons via a T-matrix with off-shell effects. The $\\pi N \\gamma$ differential cross sections are calculated using three different T-matrix models and the results are compared with the soft photon approximation, and with experimental data. The aim of this analysis is to test the off-shell behavior of the different T-matrices under consideration.

A. Mariano; G. López Castro

2000-03-31T23:59:59.000Z

183

Radiation field modeling and optimization of a compact and modular  

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

Radiation field modeling and optimization of a compact and modular Radiation field modeling and optimization of a compact and modular multi-plate photocatalytic reactor (MPPR) for air/water purification by Monte Carlo method Title Radiation field modeling and optimization of a compact and modular multi-plate photocatalytic reactor (MPPR) for air/water purification by Monte Carlo method Publication Type Journal Article Year of Publication 2013 Authors Zazueta, Ana Luisa Loo, Hugo Destaillats, and Gianluca Li Puma Journal Chemical Engineering Journal Volume 217 Pagination 475-485 Date Published 02/01/2013 Abstract The radiation field in a multi-plate photocatalytic reactor (MPPR) for air or water purification was modeled and optimized using a Monte Carlo stochastic method. The MPPR consists of parallel photocatalytic plates irradiated by cylindrical UV lamps orthogonal to the plates. The photocatalyst titanium dioxide (TiO2) is supported on the plates as a thin film. The photoreactor design is compact and offers a large irradiated photocatalytic surface area, a high degree of photon utilization, low pressure drop and a modular design which can facilitate scale-up. These features are desirable for the decontamination of indoor air in ventilation ducts or for water detoxification. The Monte Carlo method was applied to determine three dimensionless reactor performance parameters: the photon absorption efficiency (Φ), the uniformity of the distribution of the dimensionless radiation intensity (η) and the overall photonic efficiency (Φ). The emission of photons from the light sources was simulated by the extensive source with superficial emission (ESSE) model. Simulations were performed by varying the catalyst reflectivity albedo, the number and the diameter of lamps, and the dimensions and spacing of the photocatalytic plates. Optimal design for a basic reactor module with one lamp was accomplished for lamp-diameter-to-plate-height ratio (β) of 0.7, while the plate-spacing-to-plate-height ratio (α) was correlated by [αoptimum = 0.191 β2 - 0.5597 β + 0.3854]. A multilamp arrangement leads to a feasible increase in the size and number of the plates and the irradiated photocatalytic surface area. The optimum design was validated by measuring the apparent quantum yield of the oxidation of toluene (7 ppmv) in a humidified air stream using immobilized TiO2 (Degussa P25). Experiments performed varying the geometrical parameter α correlated well with the model calculations, with maximum apparent quantum yield for α = 0.137. The results are directly transferable to the treatment of water by photocatalysis.

184

Particle swarm optimization based on model space theory and its application on transmission network planning  

Science Conference Proceedings (OSTI)

A model space and space compression theory is developed. The theory defined an N-1 security network as a model, and then defined a model space according a given model. Using this theory in Particle Swarm Optimization can prevent particles form searching ... Keywords: model, model space, model structure mutation, particle swarm optimization, transmission network expansion planning

Yi-Xiong Jin; Juan Su

2007-04-01T23:59:59.000Z

185

Computational social dynamic modeling of group recruitment.  

SciTech Connect

The Seldon software toolkit combines concepts from agent-based modeling and social science to create a computationally social dynamic model for group recruitment. The underlying recruitment model is based on a unique three-level hybrid agent-based architecture that contains simple agents (level one), abstract agents (level two), and cognitive agents (level three). This uniqueness of this architecture begins with abstract agents that permit the model to include social concepts (gang) or institutional concepts (school) into a typical software simulation environment. The future addition of cognitive agents to the recruitment model will provide a unique entity that does not exist in any agent-based modeling toolkits to date. We use social networks to provide an integrated mesh within and between the different levels. This Java based toolkit is used to analyze different social concepts based on initialization input from the user. The input alters a set of parameters used to influence the values associated with the simple agents, abstract agents, and the interactions (simple agent-simple agent or simple agent-abstract agent) between these entities. The results of phase-1 Seldon toolkit provide insight into how certain social concepts apply to different scenario development for inner city gang recruitment.

Berry, Nina M.; Lee, Marinna; Pickett, Marc; Turnley, Jessica Glicken (Sandia National Laboratories, Albuquerque, NM); Smrcka, Julianne D. (Sandia National Laboratories, Albuquerque, NM); Ko, Teresa H.; Moy, Timothy David (Sandia National Laboratories, Albuquerque, NM); Wu, Benjamin C.

2004-01-01T23:59:59.000Z

186

Optimal Model of Distributed Energy System by Using GAMS and Case Study  

E-Print Network (OSTI)

Optimal Model of Distributed Energy System by Using GAMS andEnergy Reliability, Distributed Energy Program of the U.S.Optimal Model of Distributed Energy System by Using GAMS and

Yang, Yongwen; Gao, Weijun; Ruan, Yingjun; Xuan, Ji; Zhou, Nan; Marnay, Chris

2005-01-01T23:59:59.000Z

187

Enhanced affine invariant matching of broken boundaries based on particle swarm optimization and the dynamic migrant principle  

Science Conference Proceedings (OSTI)

Recently particle swarm optimization (PSO) has been successfully applied in identifying contours that are originated from different views of the same object. As compared with similar approaches based on simple genetic algorithms (SGA), the PSO exhibits ... Keywords: Affine invariant matching, Broken boundary, Dynamic migrant principle, Particle swarm optimization, Static migrant principle

Peter W. M. Tsang; Terry Y. F. Yuen; W. C. Situ

2010-03-01T23:59:59.000Z

188

Optimization Online - Coordinators  

E-Print Network (OSTI)

... Programming); William Hart — Sandia National Laboratory; (Combinatorial Optimization / Global Optimization / Optimization Software and Modeling Systems

189

Customer Equilibrium and Optimal Strategies in an M/M/1 Queue with Dynamic Service Control  

E-Print Network (OSTI)

We consider the problem of customer equilibrium strategies in an M/M/1 queue under dynamic service control. The service rate switches between a low and a high value depending on system congestion. Arriving customers do not observe the system state at the moment of arrival. We show that due to service rate variation, the customer equilibrium strategy is not generally unique, and derive an upper bound on the number of possible equilibria. For the problem of social welfare optimization, we numerically analyze the relationship between the optimal arrival rate, which maximizes the overall welfare of the customers, and the equilibrium ones as a function of various parameter values. We finally derive analytic solutions for the special case where the service rate switch occurs when the queue ceases to be empty.

Dimitrakopoulos, Y

2011-01-01T23:59:59.000Z

190

Optimal design of aeroengine turbine disc based on kriging surrogate models  

Science Conference Proceedings (OSTI)

A design optimization method based on kriging surrogate models is proposed and applied to the shape optimization of an aeroengine turbine disc. The kriging surrogate model is built to provide rapid approximations of time-consuming computations. For improving ... Keywords: Design of experiments, Differential evolutionary algorithm, Kriging method, Optimal design, Surrogate model, Turbine disc

Zhangjun Huang; Chengen Wang; Jian Chen; Hong Tian

2011-01-01T23:59:59.000Z

191

Dynamic model of power system operation incorporating load control  

SciTech Connect

Load management has been proposed as a means whereby an electric utility can reduce its requirements for additional generation, transmission, and distribution investments, shift fuel dependency from limited to more abundant energy resources, and improve the efficiency of the electric energy system. There exist, however, serious technological and economic questions which must be answered to define the cost trade-offs between initiating a load management strategy or adding additional capacity to meet the load. One aspect of this complex problem is to determine how the load profile might be modified by the load management option being considered. Towards this end, a model has been developed to determine how a power system with an active load control system should be operated to make the best use of its available resources. The model is capable of handling all types of conventional generating sources including thermal, hydro, and pumped storage units, and most appliances being considered for direct control including those with inherent or designed storage characteristics. The model uses a dynamic programming technique to determine the optimal operating strategy for a given set of conditions. The use of the model is demonstrated. Case study results indicate that the production cost savings that can be achieved through the use of direct load control are highly dependent on utility characteristics, load characteristics, storage capacity, and penetration. The load characteristics that produce the greatest savings are: large storage capacity; high coincidence with the system peak; large connected load per point; and moderately high diversity fraction.

Kuliasha, M.A.

1980-10-01T23:59:59.000Z

192

Optimal control of CPR procedure using hemodynamic circulation model  

DOE Patents (OSTI)

A method for determining a chest pressure profile for cardiopulmonary resuscitation (CPR) includes the steps of representing a hemodynamic circulation model based on a plurality of difference equations for a patient, applying an optimal control (OC) algorithm to the circulation model, and determining a chest pressure profile. The chest pressure profile defines a timing pattern of externally applied pressure to a chest of the patient to maximize blood flow through the patient. A CPR device includes a chest compressor, a controller communicably connected to the chest compressor, and a computer communicably connected to the controller. The computer determines the chest pressure profile by applying an OC algorithm to a hemodynamic circulation model based on the plurality of difference equations.

Lenhart, Suzanne M. (Knoxville, TN); Protopopescu, Vladimir A. (Knoxville, TN); Jung, Eunok (Seoul, KR)

2007-12-25T23:59:59.000Z

193

Optimization  

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

failure events, including standard model, checkpoint model, Markov Renewal Process, Bayesian model, and automatic- repeat-request (ARQ) model. They cannot be directly used in...

194

Dynamic social network analysis using latent space models  

Science Conference Proceedings (OSTI)

This paper explores two aspects of social network modeling. First, we generalize a successful static model of relationships into a dynamic model that accounts for friendships drifting over time. Second, we show how to make it tractable to learn such ...

Purnamrita Sarkar; Andrew W. Moore

2005-12-01T23:59:59.000Z

195

A Simple Model of Stratospheric Dynamics Including Solar Variability  

Science Conference Proceedings (OSTI)

A simple dynamic model, truncated from the stratospheric wave–zonal flow interaction Holton and Mass model, is introduced and studied. This model consists of three ordinary differential equations controlled by two parameters: the initial ...

Alexander Ruzmaikin; John Lawrence; Cristina Cadavid

2003-05-01T23:59:59.000Z

196

Optimization Online - Modeling the Mobile Oil Recovery Problem as ...  

E-Print Network (OSTI)

Feb 6, 2009 ... The goal of the MOR optimization Problem (MORP) is to optimize both the oil extraction and the travel costs. We describe several formulations ...

197

Modeling Dynamics of Post Disaster Recovery  

E-Print Network (OSTI)

Natural disasters result in loss of lives, damage to built facilities, and interruption of businesses. The losses are not instantaneous rather they continue to occur until the community is restored to a functional socio-economic entity. Hence, it is essential that policy makers recognize this dynamic aspect of the incurring losses and make realistic plans to enhance the recovery. However, this cannot take place without understanding how homeowners react to recovery signals. These signals can come in different ways: from policy makers showing their strong commitment to restore the community by providing financial support and/or restoration of lifeline infrastructure; or from the neighbors showing their willingness to reconstruct. The goal of this research is to develop a model that can account for homeowners’ dynamic interactions in both organizational and spatial domains. Spatial domain of interactions focuses on how homeowners process signals from the environment such as neighbors reconstructing and local agencies restoring infrastructure, while organizational domain of interactions focuses on how agents process signals from other stakeholders that do not directly affect the environment like insurers. The hypothesis of this study is that these interactions significantly influence decisions to reconstruct and stay, or sell and leave. A multi-agent framework is used to capture emergent behavior such as spatial patterns and formation of clusters. The developed framework is illustrated and validated using experimental data sets.

Nejat, Ali

2011-08-01T23:59:59.000Z

198

The dynamic North Florida dairy farm model: A user-friendly computerized tool for increasing profits while minimizing N leaching under varying climatic conditions  

Science Conference Proceedings (OSTI)

This paper describes the computer implementation of the Dynamic North Florida Dairy farm model (DyNoFlo Dairy). The DyNoFlo Dairy is a decision support system that integrates nutrient budgeting, crop, and optimization models created to assess nitrogen ... Keywords: Climate, Dairy, Florida, Leaching, Markov chains, Optimization, User friendly

Victor E. Cabrera; Norman E. Breuer; Peter E. Hildebrand; David Letson

2005-11-01T23:59:59.000Z

199

Bayesian dynamic models for space-time point processes  

Science Conference Proceedings (OSTI)

In this work we propose a model for the intensity of a space-time point process, specified by a sequence of spatial surfaces that evolve dynamically in time. This specification allows flexible structures for the components of the model, in order to handle ... Keywords: Bayesian inference, Disease mapping, Dynamic models, Integrated Laplace, Monte Carlo Markov chain, Space-time point processes

Edna A. Reis; Dani Gamerman; Marina S. Paez; Thiago G. Martins

2013-04-01T23:59:59.000Z

200

System Dynamics: HyDIVE(TM) (Hydrogen Dynamic Infrastructure and Vehicle Evolution) Model (Presentation)  

DOE Green Energy (OSTI)

This presentation by Cory Welch at the 2007 DOE Hydrogen Program Annual Merit Review Meeting focuses on Hydrogen Dynamic Infrastructure and Vehicle Evolution Model.

Welch, C.

2007-05-16T23:59:59.000Z

Note: This page contains sample records for the topic "dynamic optimization model" 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

A Game-Theoretical Dynamic Model for Electricity Markets  

E-Print Network (OSTI)

Oct 6, 2010 ... A Game-Theoretical Dynamic Model for Electricity Markets ... forecast horizon, bidding frequency, and some other factors on the price signals.

202

Lessons Learned from Alternative Transportation Fuels: Modeling Transition Dynamics  

DOE Green Energy (OSTI)

Report focuses on understanding how analytical system modeling and data from AFV experiences could improve our understanding of the dynamic forces governing the transition to a hydrogen future.

Welch, C.

2006-02-01T23:59:59.000Z

203

Supercomputer modeling of volcanic eruption dynamics  

DOE Green Energy (OSTI)

Our specific goals are to: (1) provide a set of models based on well-defined assumptions about initial and boundary conditions to constrain interpretations of observations of active volcanic eruptions--including movies of flow front velocities, satellite observations of temperature in plumes vs. time, and still photographs of the dimensions of erupting plumes and flows on Earth and other planets; (2) to examine the influence of subsurface conditions on exit plane conditions and plume characteristics, and to compare the models of subsurface fluid flow with seismic constraints where possible; (3) to relate equations-of-state for magma-gas mixtures to flow dynamics; (4) to examine, in some detail, the interaction of the flowing fluid with the conduit walls and ground topography through boundary layer theory so that field observations of erosion and deposition can be related to fluid processes; and (5) to test the applicability of existing two-phase flow codes for problems related to the generation of volcanic long-period seismic signals; (6) to extend our understanding and simulation capability to problems associated with emplacement of fragmental ejecta from large meteorite impacts.

Kieffer, S.W. [Arizona State Univ., Tempe, AZ (United States); Valentine, G.A. [Los Alamos National Lab., NM (United States); Woo, Mahn-Ling [Arizona State Univ., Tempe, AZ (United States)

1995-06-01T23:59:59.000Z

204

Development of dynamic models of reactive distillation columns for simulation and determination of control  

E-Print Network (OSTI)

Dynamic models of a reactive distillation column have been developed and implemented in this work. A model describing the steady state behavior of the system has been built in a first step. The results from this steady state model have been compared to data provided from an industrial collaborator and the reconciled model formed the basis for the development of a dynamic model. Four controlled and four manipulated variables have been determined in a subsequent step and step tests for the manipulated variables were simulated. The data generated by the step responses was used for fitting transfer functions between the manipulated and the controlled variables. RGA analysis was performed to find the optimal pairing for controller design. Feedback controllers of PID type were designed between the paired variables found from RGA and the controllers were implemented on the column model. Both servo and regulatory problems have been considered and tested.

Chakrabarty, Arnab

2004-12-01T23:59:59.000Z

205

COMPUTATIONAL FLUID DYNAMICS MODELING ANALYSIS OF COMBUSTORS  

DOE Green Energy (OSTI)

In the current fiscal year FY01, several CFD simulations were conducted to investigate the effects of moisture in biomass/coal, particle injection locations, and flow parameters on carbon burnout and NO{sub x} inside a 150 MW GEEZER industrial boiler. Various simulations were designed to predict the suitability of biomass cofiring in coal combustors, and to explore the possibility of using biomass as a reburning fuel to reduce NO{sub x}. Some additional CFD simulations were also conducted on CERF combustor to examine the combustion characteristics of pulverized coal in enriched O{sub 2}/CO{sub 2} environments. Most of the CFD models available in the literature treat particles to be point masses with uniform temperature inside the particles. This isothermal condition may not be suitable for larger biomass particles. To this end, a stand alone program was developed from the first principles to account for heat conduction from the surface of the particle to its center. It is envisaged that the recently developed non-isothermal stand alone module will be integrated with the Fluent solver during next fiscal year to accurately predict the carbon burnout from larger biomass particles. Anisotropy in heat transfer in radial and axial will be explored using different conductivities in radial and axial directions. The above models will be validated/tested on various fullscale industrial boilers. The current NO{sub x} modules will be modified to account for local CH, CH{sub 2}, and CH{sub 3} radicals chemistry, currently it is based on global chemistry. It may also be worth exploring the effect of enriched O{sub 2}/CO{sub 2} environment on carbon burnout and NO{sub x} concentration. The research objective of this study is to develop a 3-Dimensional Combustor Model for Biomass Co-firing and reburning applications using the Fluent Computational Fluid Dynamics Code.

Mathur, M.P.; Freeman, Mark (U.S. DOE National Energy Technology Laboratory); Gera, Dinesh (Fluent, Inc.)

2001-11-06T23:59:59.000Z

206

Characteristics of identifying linear dynamic models from impulse response data using Prony analysis  

SciTech Connect

The purpose of the study was to investigate the characteristics of fitting linear dynamic models to the impulse response of oscillatory dynamic systems using Prony analysis. Many dynamic systems exhibit oscillatory responses with multiple modes of oscillations. Although the underlying dynamics of such systems are often nonlinear, it is frequently possible and very useful to represent the system operating about some set point with a linear model. Derivation of such linear models can be done using two basic approaches: model the system using theoretical derivations and some linearization method such as a Taylor series expansion; or use a curve-fitting technique to optimally fit a linear model to specified system response data. Prony analysis belongs to the second class of system modeling because it is a method of fitting a linear model to the impulse response of a dynamic system. Its parallel formulation inherently makes it well suited for fitting models to oscillatory system data. Such oscillatory dynamic effects occur in large synchronous-generator-based power systems in the form of electromechanical oscillations. To study and characterize these oscillatory dynamics, BPA has developed computer codes to analyze system data using Prony analysis. The objective of this study was to develop a highly detailed understanding of the properties of using Prony analysis to fit models to systems with characteristics often encountered in power systems. This understanding was then extended to develop general rules-of-thumb'' for using Prony analysis. The general characteristics were investigated by performing fits to data from known linear models under controlled conditions. The conditions studied include various mathematical solution techniques; different parent system configurations; and a large variety of underlying noise characteristics.

Trudnowski, D.J.

1992-12-01T23:59:59.000Z

207

Characteristics of identifying linear dynamic models from impulse response data using Prony analysis  

SciTech Connect

The purpose of the study was to investigate the characteristics of fitting linear dynamic models to the impulse response of oscillatory dynamic systems using Prony analysis. Many dynamic systems exhibit oscillatory responses with multiple modes of oscillations. Although the underlying dynamics of such systems are often nonlinear, it is frequently possible and very useful to represent the system operating about some set point with a linear model. Derivation of such linear models can be done using two basic approaches: model the system using theoretical derivations and some linearization method such as a Taylor series expansion; or use a curve-fitting technique to optimally fit a linear model to specified system response data. Prony analysis belongs to the second class of system modeling because it is a method of fitting a linear model to the impulse response of a dynamic system. Its parallel formulation inherently makes it well suited for fitting models to oscillatory system data. Such oscillatory dynamic effects occur in large synchronous-generator-based power systems in the form of electromechanical oscillations. To study and characterize these oscillatory dynamics, BPA has developed computer codes to analyze system data using Prony analysis. The objective of this study was to develop a highly detailed understanding of the properties of using Prony analysis to fit models to systems with characteristics often encountered in power systems. This understanding was then extended to develop general ``rules-of-thumb`` for using Prony analysis. The general characteristics were investigated by performing fits to data from known linear models under controlled conditions. The conditions studied include various mathematical solution techniques; different parent system configurations; and a large variety of underlying noise characteristics.

Trudnowski, D.J.

1992-12-01T23:59:59.000Z

208

Modeling of a QoS Matching and Optimization Function for Multimedia Services in the NGN  

Science Conference Proceedings (OSTI)

A key challenge for Next Generation Networks (NGN) is providing support for the negotiation and dynamic adaptation of Quality of Service (QoS) parameters. In this paper we propose a novel QoS Matching and Optimization Function (Q-MOF) ... Keywords: QoS matching, QoS optimization, multimedia services, next generation network

Lea Skorin-Kapov; Maja Matijasevic

2009-10-01T23:59:59.000Z

209

Optimal Control of Distributed Energy Resources using Model Predictive Control  

Science Conference Proceedings (OSTI)

In an isolated power system (rural microgrid), Distributed Energy Resources (DERs) such as renewable energy resources (wind, solar), energy storage and demand response can be used to complement fossil fueled generators. The uncertainty and variability due to high penetration of wind makes reliable system operations and controls challenging. In this paper, an optimal control strategy is proposed to coordinate energy storage and diesel generators to maximize wind penetration while maintaining system economics and normal operation. The problem is formulated as a multi-objective optimization problem with the goals of minimizing fuel costs and changes in power output of diesel generators, minimizing costs associated with low battery life of energy storage and maintaining system frequency at the nominal operating value. Two control modes are considered for controlling the energy storage to compensate either net load variability or wind variability. Model predictive control (MPC) is used to solve the aforementioned problem and the performance is compared to an open-loop look-ahead dispatch problem. Simulation studies using high and low wind profiles, as well as, different MPC prediction horizons demonstrate the efficacy of the closed-loop MPC in compensating for uncertainties in wind and demand.

Mayhorn, Ebony T.; Kalsi, Karanjit; Elizondo, Marcelo A.; Zhang, Wei; Lu, Shuai; Samaan, Nader A.; Butler-Purry, Karen

2012-07-22T23:59:59.000Z

210

Implications of a Regime-Switching Model on Natural Gas Storage Valuation and Optimal Operation  

E-Print Network (OSTI)

Implications of a Regime-Switching Model on Natural Gas Storage Valuation and Optimal Operation-switching model for the risk adjusted natural gas spot price and study the implications of the model on the valuation and optimal operation of natural gas storage facilities. We calibrate the model parameters to both

Forsyth, Peter A.

211

Onverter Center of Gravity and Tilting Torque Dynamic Model Simulation  

Science Conference Proceedings (OSTI)

Using SolidWorks software to3D solid modeling of steelmaking converter and liquid steel to get their center of gravity coordinates, so as to optimize the location of the trunnion, that used to determine the best location of the converter trunnion. Based ... Keywords: Converter, Optimization, Tilting, Torque

Lichen Li, Yunfeng Liu, Shaoqing Ren, Tongqing Li

2012-07-01T23:59:59.000Z

212

Optimization of source-sink dynamics in plant growth for ideotype breeding: A case study on maize  

Science Conference Proceedings (OSTI)

The objective of this work is to illustrate how a mathematical model of plant growth could be possibly used to design ideotypes and thus leads to new breeding strategies based on the guidance from optimization techniques. As a test case, maize (Zea mays ... Keywords: Functional-structural model, GreenLab, Multi-objective optimization, Pareto front, Zea mays

Rui Qi; Yuntao Ma; Baogang Hu; Philippe de Reffye; Paul-Henry Cournède

2010-04-01T23:59:59.000Z

213

Ocean Eddy Dynamics in a Coupled Ocean–Atmosphere Model  

Science Conference Proceedings (OSTI)

The role of mesoscale oceanic eddies is analyzed in a quasigeostrophic coupled ocean–atmosphere model operating at a large Reynolds number. The model dynamics are characterized by decadal variability that involves nonlinear adjustment of the ...

P. Berloff; W. Dewar; S. Kravtsov; J. McWilliams

2007-05-01T23:59:59.000Z

214

Growth-optimal investments and numeraire portfolios under transaction costs: An analysis based on the von Neumann-Gale model  

E-Print Network (OSTI)

The aim of this work is to extend the capital growth theory developed by Kelly, Breiman, Cover and others to asset market models with transaction costs. We define a natural generalization of the notion of a numeraire portfolio proposed by Long and show how such portfolios can be used for constructing growth-optimal investment strategies. The analysis is based on the classical von Neumann-Gale model of economic dynamics, a stochastic version of which we use as a framework for the modelling of financial markets with frictions.

Bahsoun, Wael; Taksar, Michael I

2009-01-01T23:59:59.000Z

215

Dynamic modelling of metals - Time scales and target loads  

Science Conference Proceedings (OSTI)

Over the past decade steady-state methods have been developed to assess critical loads of metals avoiding long-term risks in view of food quality and eco-toxicological effects on organisms in soils and surface waters. However, dynamic models are needed ... Keywords: Critical loads, Delay times, Dynamic modelling, Metals, Scenario analysis, Target loads

Maximilian Posch; Wim de Vries

2009-01-01T23:59:59.000Z

216

Mathematical modeling of irreversible dynamic deformation, micro...  

National Nuclear Security Administration (NNSA)

proceed in deformable solids under intensive dynamic loading, consist of mechanical, thermal and structural ones, which correlate themselves. The structural processes involve the...

217

A Dynamical Systems Model for Nuclear Power Plant Risk Management  

Science Conference Proceedings (OSTI)

This report provides a mathematical dynamical systems model of the effect of plant processes and programs on nuclear plant safety. That is, it models the safety risk management process. Responses of this model to postulated changes in performance and coupling parameters were verified to be in accordance with experience from years of commercial nuclear power plant operation. A preliminary analysis of the model was performed using the techniques of dynamical systems theory to determine regions of operation...

2003-10-31T23:59:59.000Z

218

11/11/2002 1AVS 49th Int'l Symp. MS-MoA7 (Oct. 29, 2002) -Cho Dynamic Simulation and Optimization  

E-Print Network (OSTI)

'l Symp. MS-MoA7 (Oct. 29, 2002) - Cho Scope & Strategy Multilevel modeling & simulation incorporating dynamics &Multilevel modeling & simulation incorporating dynamics & stochasticsstochastics ESH fluctuations Incorporate capability in models for dynamics & stochastics Process & tool Fundamental science Si

Rubloff, Gary W.

219

Electrodiffusive model for astrocytic and neuronal ion concentration dynamics  

E-Print Network (OSTI)

Electrical neural signalling typically takes place at the time-scale of milliseconds, and is typically modeled using the cable equation. This is a good approximation for processes when ionic concentrations vary little during the time course of a simulation. During periods of intense neural signalling, however, the local extracellular K+ concentration may increase by several millimolars. Clearance of excess K+ likely depends partly on diffusion in the extracellular space, partly on local uptake by- and intracellular transport within astrocytes. This process takes place at the time scale of seconds, and can not be modeled accurately without accounting for the spatiotemporal variations in ion concentrations. The work presented here consists of two main parts: First, we developed a general electrodiffusive formalism for modeling ion concentration dynamics in a one-dimensional geometry, including both an intra- and extracellular domain. The formalism was based on the Nernst-Planck equations. It ensures (i) consistency between the membrane potential and ion concentrations, (ii) global particle/charge conservation, and (iii) accounts for diffusion and concentration dependent variations in resistivities. Second, we applied the formalism to model how astrocytes exchange ions with the ECS, and identified the key astrocytic mechanisms involved in K+ removal from high concentration regions. We found that a local increase in extracellular K\\textsuperscript{+} evoked a local depolarization of the astrocyte membrane, which at the same time (i) increased the local astrocytic uptake of K\\textsuperscript{+}, (ii) suppressed extracellular transport of K+, (iii) increased transport of K+ within astrocytes, and (iv) facilitated astrocytic relase of K+ in extracellular low concentration regions. In summary, these mechanisms seem optimal for shielding the extracellular space from excess K+.

Geir Halnes; Ivar Østby; Klas H. Pettersen; Stig W. Omholt; Gaute T. Einevoll

2013-04-29T23:59:59.000Z

220

Using Genetic Algorithms to Optimize Bathymetric Sampling for Predictive Model Input  

Science Conference Proceedings (OSTI)

This paper describes the use of an optimization method to effectively reduce the required bathymetric sampling for forcing a numerical forecast model by using the model’s sensitivity to this input. A genetic algorithm is developed to gradually ...

Dinesh Manian; James M. Kaihatu; Emily M. Zechman

2012-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamic optimization model" 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

An Efficient Stochastic Bayesian Approach to Optimal Parameter and Uncertainty Estimation for Climate Model Predictions  

Science Conference Proceedings (OSTI)

One source of uncertainty for climate model predictions arises from the fact that climate models have been optimized to reproduce observational means. To quantify the uncertainty resulting from a realistic range of model configurations, it is ...

Charles Jackson; Mrinal K. Sen; Paul L. Stoffa

2004-07-01T23:59:59.000Z

222

Dynamic Modeling in Solid-Oxide Fuel Cells Controller Design  

SciTech Connect

In this paper, a dynamic model of the solid-oxide fuel cell (SOFC) power unit is developed for the purpose of designing a controller to regulate fuel flow rate, fuel temperature, air flow rate, and air temperature to maintain the SOFC stack temperature, fuel utilization rate, and voltage within operation limits. A lumped model is used to consider the thermal dynamics and the electro-chemial dynamics inside an SOFC power unit. The fluid dynamics at the fuel and air inlets are considered by using the in-flow ramp-rates.

Lu, Ning; Li, Qinghe; Sun, Xin; Khaleel, Mohammad A.

2007-06-28T23:59:59.000Z

223

A Research on Production Optimization of Coupled Surface and Subsurface Model  

E-Print Network (OSTI)

One of the main objectives in the Oil & Gas Industry is to constantly improve the reservoir management capabilities by using production optimization strategies that can positively impact the so-called net-present value (NPV) of a given project. In order to achieve this goal the industry is faced with the difficult task of maximizing hydrocarbon production and minimizing unwanted fluids, such as water, while sustaining or even enhancing the reservoir recovery factor by handling properly the fluids at surface facilities. A key element in this process is the understanding of the interactions between subsurface and subsurface dynamics in order to provide insightful production strategies which honor reservoir management surface facility constraints. The implementation of the ideal situation of fully coupling surface/subsurface has been hindered by the required computational efforts involved in the process. Consequently, various types of partially coupling that require less computational efforts are practically implemented. Due to importance of coupling surface and subsurface model on production optimization and taking the advantage of advancing computational performance, this research explores the concept of surface and subsurface model couplings and production optimization. The research aims at demonstrating the role of coupling of surface and subsurface model on production optimization under simple production constraint (i.e. production and injection pressure limit). The normal production prediction runs with various reservoir description (homogeneous-low permeability, homogeneous-high permeability, and heterogeneous permeability) and different fluid properties (dead-oil PVT and lived-oil PVT) were performed in order to understand the effect of coupling level, and coupling scheme with different reservoir descriptions and fluid properties on production and injection rate prediction. The result shows that for dead-oil PVT, the production rate from different coupling schemes in homogeneous and heterogeneous reservoir is less sensitive than lived-oil PVT cases. For lived-oil PVT, the production rate from different coupling schemes in homogeneous high permeability and heterogeneous permeability are more sensitive than homogeneous low permeability. The production optimization on water flooding under production and injection constraint cases is considered here also.

Iemcholvilert, Sevaphol

2013-08-01T23:59:59.000Z

224

Intelligent process modeling and optimization of die-sinking electric discharge machining  

Science Conference Proceedings (OSTI)

This paper reports an intelligent approach for process modeling and optimization of electric discharge machining (EDM). Physics based process modeling using finite element method (FEM) has been integrated with the soft computing techniques like artificial ... Keywords: Artificial neural networks (ANN), Electric discharge machining (EDM), Finite element method (FEM), Non-dominated sorting genetic algorithm (NSGA), Process modeling and optimization, Scaled conjugate gradient algorithm (SCG)

S. N. Joshi; S. S. Pande

2011-03-01T23:59:59.000Z

225

ARIMA Model Estimated by Particle Swarm Optimization Algorithm for Consumer Price Index Forecasting  

Science Conference Proceedings (OSTI)

This paper presents an ARIMA model which uses particle swarm optimization algorithm (PSO) for model estimation. Because the traditional estimation method is complex and may obtain very bad results, PSO which can be implemented with ease and has a powerful ... Keywords: ARIMA model, Consumer price index, Moment estimation, Particle swarm optimization algorithm

Hongjie Wang; Weigang Zhao

2009-11-01T23:59:59.000Z

226

Dynamic cone beam CT angiography of carotid and cerebral arteries using canine model  

SciTech Connect

Purpose: This research is designed to develop and evaluate a flat-panel detector-based dynamic cone beam CT system for dynamic angiography imaging, which is able to provide both dynamic functional information and dynamic anatomic information from one multirevolution cone beam CT scan. Methods: A dynamic cone beam CT scan acquired projections over four revolutions within a time window of 40 s after contrast agent injection through a femoral vein to cover the entire wash-in and wash-out phases. A dynamic cone beam CT reconstruction algorithm was utilized and a novel recovery method was developed to correct the time-enhancement curve of contrast flow. From the same data set, both projection-based subtraction and reconstruction-based subtraction approaches were utilized and compared to remove the background tissues and visualize the 3D vascular structure to provide the dynamic anatomic information. Results: Through computer simulations, the new recovery algorithm for dynamic time-enhancement curves was optimized and showed excellent accuracy to recover the actual contrast flow. Canine model experiments also indicated that the recovered time-enhancement curves from dynamic cone beam CT imaging agreed well with that of an IV-digital subtraction angiography (DSA) study. The dynamic vascular structures reconstructed using both projection-based subtraction and reconstruction-based subtraction were almost identical as the differences between them were comparable to the background noise level. At the enhancement peak, all the major carotid and cerebral arteries and the Circle of Willis could be clearly observed. Conclusions: The proposed dynamic cone beam CT approach can accurately recover the actual contrast flow, and dynamic anatomic imaging can be obtained with high isotropic 3D resolution. This approach is promising for diagnosis and treatment planning of vascular diseases and strokes.

Cai Weixing; Zhao Binghui; Conover, David; Liu Jiangkun; Ning Ruola [Department of Imaging Sciences, University of Rochester, 601 Elmwood Avenue, Rochester, New York 14642 (United States); Department of Radiology, Shanghai 6th People's Hospital, 600 Yishan Road, Xuhui, Shanghai (China); Koning Corporation, Lennox Tech Enterprise Center, 150 Lucius Gordon Drive Suite 112, West Henrietta, New York 14586 (United States); Department of Imaging Sciences, University of Rochester, 601 Elmwood Avenue, Rochester, New York 14642 (United States); Department of Imaging Sciences, University of Rochester, 601 Elmwood Avenue, Rochester, New York 14642 (United States) and Koning Corporation, Lennox Tech Enterprise Center, 150 Lucius Gordon Drive Suite 112, West Henrietta, New York 14586 (United States)

2012-01-15T23:59:59.000Z

227

Genetic algorithm based optimization of advanced solar cell designs modeled in Silvaco AtlasTM .  

E-Print Network (OSTI)

??A genetic algorithm was used to optimize the power output of multi-junction solar cells. Solar cell operation was modeled using the Silvaco ATLASTM software. The… (more)

Utsler, James

2006-01-01T23:59:59.000Z

228

Techniques for Battery Health Conscious Power Management via Electrochemical Modeling and Optimal Control.  

E-Print Network (OSTI)

??This dissertation combines electrochemical battery models and optimal control theory to study power management in energy storage/conversion systems. This topic is motivated by the need… (more)

Moura, Scott J.

2011-01-01T23:59:59.000Z

229

Applying the Battery Ownership Model in Pursuit of Optimal Battery Use Strategies (Presentation)  

DOE Green Energy (OSTI)

This Annual Merit Review presentation describes the application of the Battery Ownership Model for strategies for optimal battery use in electric drive vehicles (PEVs, PHEVs, and BEVs).

Neubauer, J.; Ahmad, P.; Brooker, A.; Wood, E.; Smith, K.; Johnson, C.; Mendelsohn, M.

2012-05-01T23:59:59.000Z

230

A Game-Dynamic Model of Gas Transportation Routes and Its Application . . .  

E-Print Network (OSTI)

The purpose of this paper is to study an optimal structure of a system of international gas pipelines competing for a gas market. We develop a game-dynamic model of the operation of several interacting gas pipeline projects with project owners acting as players in the game. The model treats the projects' commercialization times as major players' controls. Current quantities of gas supply are modeled as approximations to Nash equilibrium points in instantaneous "gas supply games", in which each player maximizes his/her current netprofit due to the sales of gas. We use the model to analyze the Turkish gas market, on which gas routes originating from Russia, Turkmenistan and Iran are competing. The analysis is carried out in three steps. At step 1, we model the operation of the pipelines as planned and estimate the associated profits. At step 2, we optimize individual projects, with respect to their profits, assuming that the other pipelines operate as planned. At step 3, we find numerical Nash equilibrium commercialization policies for the entire group of the pipelines. The simulations show the degrees to which the planned regimes are not optimal compared to the Nash equilibrium ones. Another observation is that in equilibrium regimes the pipelines are not always being run at their full capacities, which implies that the proposed pipeline capacities might not be optimal. The simulation results turn out to be moderately sensitive to changes in the discount rate and highly sensitive to changes in the price elasticity of gas demand.

Ger Klaassen; Ivan Matrosov; Alexander Roehrl; Alexander Tarasyev; Arkadii Kryazhimskii

2003-01-01T23:59:59.000Z

231

Estimation dynamical model of an anaerobic digestion of shrimp culture pond sediment in a biogas process using genetic algorithm  

Science Conference Proceedings (OSTI)

Biogas is one type of renewable energy which is important to the energy and environmental planning of Thailand. The study and analysis of the dynamical model of the biogas process can be explained the variables that affect biogas process and optimization. ... Keywords: anaerobic digestion, artificial intelligence, biogas process, mass balance equation, system identification

Jiraphon Srisertpol; Prasit Srinakorn; Adtavirod Kheawnak; Kontorn Chamniprasart; Arthit Srikaew

2010-10-01T23:59:59.000Z

232

Repetitive Decision Making and the Value of Forecasts in the Cost?Loss Ratio Situation: A Dynamic Model  

Science Conference Proceedings (OSTI)

The purposes of this paper are to describe a dynamic model for repetitive decision?making in the cost–loss ratio situation and to present some theoretical and numerical results related to the optimal use and economic value of weather forecasts ...

Allan H. Murphy; Richard W. Katz; Robert L. Winkler; Wu-Ron Hsu

1985-05-01T23:59:59.000Z

233

Abstract--A stochastic dynamic programming hydrothermal dispatch model to simulate a bid-based market is  

E-Print Network (OSTI)

on dynamic programming that optimizes and validates the bid prices strategies for each power plant in a hydro-thermal, and simulating them as if they were a single power plant. In a hydro-thermal system as the one simulated several plants. Emphasis is given to hydro reservoir modeling and to the assessment of their market power

Catholic University of Chile (Universidad Católica de Chile)

234

Strategies for integrated modeling: The community surface dynamics modeling system example  

Science Conference Proceedings (OSTI)

The Community Surface Dynamics Modeling System (CSDMS) is a community of earth scientists promoting the modeling of earth surface processes by developing and disseminating integrated software modules that predict the movement of fluids, and the flux ... Keywords: Community modeling, Earth surface dynamics, Governance, Model integration

Irina Overeem; Maureen M. Berlin; James P. M. Syvitski

2013-01-01T23:59:59.000Z

235

Fuzzy-Pareto-dominance driven possibilistic model based planning of electrical distribution systems using multi-objective particle swarm optimization  

Science Conference Proceedings (OSTI)

This paper presents a fuzzy-Pareto dominance driven possibilistic model based planning of electrical distribution systems using multi-objective particle swarm optimization (MOPSO). This multi-objective planning model captures the possibilistic variations ... Keywords: Electrical distribution system planning, Fuzzy-Pareto-dominance, Multi-objective optimization, Pareto-optimality, Particle swarm optimization, Possibilistic load model

N. C. Sahoo; S. Ganguly; D. Das

2012-01-01T23:59:59.000Z

236

Dynamic physical and economic modelling of riparian restoration options  

Science Conference Proceedings (OSTI)

A dynamic simulation framework is used to compare benefit-cost ratios of riparian restoration investment strategies to pursue ecosystem service benefits. The model is meant to be adaptable to generic restoration planning applications, with the Middle ... Keywords: Adaptive management, Benefit-cost analysis, Choice experiment, Dynamic simulation, Ecosystem service, Rio Grande, River restoration

Matthew A. Weber; Vincent C. Tidwell; Jennifer A. Thacher

2010-12-01T23:59:59.000Z

237

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

238

Continuously Optimized Reliable Energy (CORE) Microgrid: Models & Tools (Fact Sheet)  

SciTech Connect

This brochure describes Continuously Optimized Reliable Energy (CORE), a trademarked process NREL employs to produce conceptual microgrid designs. This systems-based process enables designs to be optimized for economic value, energy surety, and sustainability. Capabilities NREL offers in support of microgrid design are explained.

Not Available

2013-07-01T23:59:59.000Z

239

Dynamic heat capacity of the east model and of a bead-spring polymer model.  

SciTech Connect

In this report we have presented a brief review of the glass transition and one means of characterizing glassy materials: linear and nonlinear thermodynamic oscillatory experiments to extract the dynamic heat capacity. We have applied these methods to the east model (a variation of the Ising model for glass forming systems) and a simple polymeric system via molecular dynamics simulation, and our results match what is seen in experiment. For the east model, since the dynamics are so simple, a mathematical model is developed that matches the simulated dynamics. For the polymeric system, since the system is a simulation, we can instantaneously 'quench' the system - removing all vibrational energy - to separate the vibrational dynamics from dynamics associated with particle rearrangements. This shows that the long-time glassy dynamics are due entirely to the particle rearrangements, i.e. basin jumping on the potential energy landscape. Finally, we present an extension of linear dynamic heat capacity to the nonlinear regime.

McCoy, John Dwane (New Mexico Institute of Mining and Technology, Socorro, NM); Brown, Jonathan R. (New Mexico Institute of Mining and Technology, Socorro, NM); Adolf, Douglas Brian

2011-10-01T23:59:59.000Z

240

Symbolic Dynamics in a Matching Labour Market Model  

E-Print Network (OSTI)

In this paper we apply the techniques of symbolic dynamics to the analysis of a labor market which shows large volatility in employment flows. In a recent paper, Bhattacharya and Bunzel \\cite{BB} have found that the discrete time version of the Pissarides-Mortensen matching model can easily lead to chaotic dynamics under standard sets of parameter values. To conclude about the existence of chaotic dynamics in the numerical examples presented in the paper, the Li-Yorke theorem or the Mitra sufficient condition were applied which seems questionable because they may lead to misleading conclusions. Moreover, in a more recent version of the paper, Bhattacharya and Bunzel \\cite{BB1} present new results in which chaos is completely removed from the dynamics of the model. Our paper explores the matching model so interestingly developed by the authors with the following objectives in mind: (i) to show that chaotic dynamics may still be present in the model for standard parameter values; (ii) to clarify some open questions raised by the authors in \\cite{BB}, by providing a rigorous proof of the existence of chaotic dynamics in the model through the computation of topological entropy in a symbolic dynamics setting.

Diana A. Mendes; Vivaldo M. Mendes; J. Sousa Ramos

2006-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamic optimization model" 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

Compressible Convection and Subduction: Kinematic and Dynamic Modeling.  

E-Print Network (OSTI)

??Subduction is a dynamic and time-dependent process which requires time-dependent models for its study. In addition, due to the very high pressures within the Earthâs… (more)

Lee, Changyeol

2010-01-01T23:59:59.000Z

242

Dynamical Modeling of Flow in Cumulus-Filled Boundary Layers  

Science Conference Proceedings (OSTI)

A primitive equation planetary boundary layer (PBL) model is constructed and applied to simulate the downwind evolution of coupled dynamic, thermodynamic and cloud properties in the PBL over warmer mean. A multilayered approach is adopted to ...

Chiu-Wai Yuen

1985-01-01T23:59:59.000Z

243

Chaff Seeding Effects in a Dynamical-Electrical Cloud Model  

Science Conference Proceedings (OSTI)

A two-dimensional, slab-symmetric, time-dependent cloud model has been devised to simulate deep convection in the atmosphere. The dynamics and thermodynamics of deep convection are prescribed and the microphysics of the liquid phase is ...

John H. Helsdon Jr.

1980-09-01T23:59:59.000Z

244

A Representation of Variable Root Distribution in Dynamic Vegetation Models  

Science Conference Proceedings (OSTI)

Root distribution is treated as a static component in most current dynamic vegetation models (DVMs). While changes in leaf and stem biomass are reflected in leaf area index (LAI) and vegetation height via specific leaf area (SLA) and allometric ...

Vivek K. Arora; George J. Boer

2003-06-01T23:59:59.000Z

245

Applications of axial and radial compressor dynamic system modeling  

E-Print Network (OSTI)

The presented work is a compilation of four different projects related to axial and centrifugal compression systems. The projects are related by the underlying dynamic system modeling approach that is common in all of them. ...

Spakovszky, Zoltán S. (Zoltán Sándor), 1972-

2001-01-01T23:59:59.000Z

246

Vorticity Dynamics and Zonally Averaged Ocean Circulation Models  

Science Conference Proceedings (OSTI)

Diagnostic equations relating the zonally averaged overturning circulation to north–south density variations are derived and used to determine a new closure scheme for use in zonally averaged ocean models. The presentation clarifies the dynamical ...

Daniel G. Wright; Cornelis B. Vreugdenhil; Tertia M. C. Hughes

1995-09-01T23:59:59.000Z

247

Using the NOABL flow model and mathematical optimization as a micrositing tool  

DOE Green Energy (OSTI)

This report describes the use of an improved mass-consistent model that is intended for diagnosing wind fields in complex terrain. The model was developed by merging an existing mass-consistent model, the NOABL model, with an optimization procedure. The optimization allows objective calculation of important model input parameters that previously had been supplied through guesswork; in this manner, the accuracy of the calculated winds has been greatly increased. The report covers such topics as the software structure of the model, assembling an input file, processing the model's output, and certain cautions about the model's operation. The use of the model is illustrated by a test case.

Wegley, H.L.; Barnard, J.C.

1986-11-01T23:59:59.000Z

248

Modeling Residual Chlorine Decay for Optimization of Booster Chlorination in Urban-rural Water Distribution System  

Science Conference Proceedings (OSTI)

The key procedure of optimization of the control of the booster chlorination is modeling the relationship between the concentration of the spot of the booster chlorination (after dosing) and the concentration of the monitoring points on the remote end ... Keywords: Residual chlorine decay, Hybrid transfer function model, Optimization of booster chlorination, Urban-rural water distribution system

Jingqing Liu; Zuozi Huang; Shengwei Tan

2012-05-01T23:59:59.000Z

249

BaF2for microlithography applications: Modeling, simulation and optimization of the crystal growth process  

Science Conference Proceedings (OSTI)

Optimization is the ultimate goal of numerical modeling of crystal growth processes. We present the most important physical phenomena to establish a numerical process model for an industrial vertical gradient freeze (VGF) process of barium fluoride (BaF"2). ... Keywords: 44.05.+e, 81.10.Fq, Heat and mass transfer, Heat radiation, Process optimization

Rainer Backofen; Angel Ribalta; Axel Voigt; Dirk Wulff-Molder

2007-06-01T23:59:59.000Z

250

Applications of agent-based models for optimization problems: A literature review  

Science Conference Proceedings (OSTI)

Agent based models (ABM) have been recently applied to solve optimization problems whose domains present several inter-related components in a distributed and heterogeneous environment. In this work we illustrate the state of the art related to the use ... Keywords: Agent-based modeling, Heuristics, Optimization problems

M. Barbati; G. Bruno; A. Genovese

2012-04-01T23:59:59.000Z

251

MODEL AND OPTIMIZATION OF ORGANIC PHOTOVOLTAIC CELLS Amelia McNamara  

E-Print Network (OSTI)

MODEL AND OPTIMIZATION OF ORGANIC PHOTOVOLTAIC CELLS By Amelia McNamara Jordan Seering and Yi Zeng: 612/626-7370 URL: http://www.ima.umn.edu #12;Model and Optimization of Organic Photovoltaic Cells the organic photovoltaic cell, an important topic in the energy industry which has not been well studied. We

252

Modeling risk and simulation-based optimization of channel depths at Cam Pha Coal Port  

Science Conference Proceedings (OSTI)

This paper presents a simulation-based method and a risk model of ship grounding for a long-term optimization of channel depths. The long-term optimization of channel depths should be considered a two-stage process: Firstly, establishing a ship entrance ... Keywords: entrance channel, risk modeling, ship grounding, simulation

N. M. Quy; J. K. Vrijling; P. H. A. J. M Gelder; R. Groenveld

2007-10-01T23:59:59.000Z

253

Stochastic optimization of a biologically plausible spino-neuromuscular system model  

Science Conference Proceedings (OSTI)

Simulations and modeling techniques are becoming increasingly important in understanding the behavior of biological systems. Detailed models help researchers answer questions in diverse areas such as the behavior of bacteria and viruses and aiding in ... Keywords: Biological neural networks, Breeding swarm optimizers, Genetic algorithms, Particle swarm optimizers

Stanley Gotshall; Kathy Browder; Jessica Sampson; Terence Soule; Richard Wells

2007-12-01T23:59:59.000Z

254

Analytical modeling of SRAM dynamic stability  

Science Conference Proceedings (OSTI)

In this paper, for the first time, a theory for evaluating dynamic noise margins of SRAM cells is developed analytically. The results allow predicting the transient error susceptibility of an SRAM cell using a closed-form expression. The key innovation ...

Bin Zhang; Ari Arapostathis; Sani Nassif; Michael Orshansky

2006-11-01T23:59:59.000Z

255

A Dynamic Model of the Indoor Channel  

Science Conference Proceedings (OSTI)

This paper proposes a new approach to modeling the radio channel experienced by transceivers moving in an indoor environment. For modeling the time-varying impulse response (IR) a randomly time-varying power-delay profile (PDP) is used, which ... Keywords: channel measurements, indoor channel modeling, ray clustering, time-varying PDP, wide band model

Jesper Ødum Nielsen; Valentine Afanassiev; Jørgen Bach Andersen

2001-11-01T23:59:59.000Z

256

Developing Generic Dynamic Models for the 2030 Eastern Interconnection Grid  

SciTech Connect

The Eastern Interconnection Planning Collaborative (EIPC) has built three major power flow cases for the 2030 Eastern Interconnection (EI) based on various levels of energy/environmental policy conditions, technology advances, and load growth. Using the power flow cases, this report documents the process of developing the generic 2030 dynamic models using typical dynamic parameters. The constructed model was validated indirectly using the synchronized phasor measurements by removing the wind generation temporarily.

Kou, Gefei [ORNL] [ORNL; Hadley, Stanton W [ORNL] [ORNL; Markham, Penn N [ORNL] [ORNL; Liu, Yilu [ORNL] [ORNL

2013-12-01T23:59:59.000Z

257

Finite Element Modelling and Molecular Dynamic Simulations of Carbon nanotubes/ Polymer Composites  

E-Print Network (OSTI)

Modeling of single-walled carbon nanotubes, multi-walled nanotubes and nanotube reinforced polymer composites using both the Finite Element method and the Molecular Dynamic simulation technique is presented. Nanotubes subjected to mechanical loading have been analyzed. Elastic moduli and thermal coefficient of expansion are calculated and their variation with diameter and length is investigated. In particular, the nanotubes are modeled using 3D elastic beam finite elements with six degrees of freedom at each node. The difficulty in modeling multi walled nanotubes is the van der Waal's forces between adjacent layers which are geometrically non linear in nature. These forces are modeled using truss elements. The nanotube-polymer interface in a nano-composite is modeled on a similar basis. While performing the molecular dynamic simulations, the geometric optimization is performed initially to obtain the minimized configuration and then the desired temperature is attained by rescaling the velocities of carbon atoms in the nanotube. Results show that the Young's modulus increases with tube diameter in molecular mechanics whereas decreases in molecular dynamics since the inter-atomic potential due to chemical reactions between the atoms is taken into consideration in molecular dynamics unlike in molecular mechanics.

Gaddamanugu, Dhatri

2009-05-01T23:59:59.000Z

258

Dual Estimates of the Optimal Plan Model and Regional Market Costs: A Relationship  

Science Conference Proceedings (OSTI)

The relationship between linear programming dual estimates for the optimal production plan model and real regional market costs is studied. A two-stage linear programming model is necessary for exact approximation of cost allocation in analyzing with ...

Yu. M. Tsodikov; Ya. Yu. Tsodikova

2001-04-01T23:59:59.000Z

259

Modeling System Development for the Evaluation of Dynamic Air Quality  

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

Modeling System Development for the Evaluation of Dynamic Air Quality Modeling System Development for the Evaluation of Dynamic Air Quality Impacts of DER Speaker(s): Robert Van Buskirk Date: January 30, 2003 - 12:00pm Location: Bldg. 90 Seminar Host/Point of Contact: Kristina LaCommare A critical challenge for the atmospheric sciences is to understand the anthropogenic impacts on atmospheric chemistry over spatial scales ranging from the urban to the regional, and ultimately to the global, and over corresponding time scales ranging from minutes to weeks and ultimately annual trends. A similar challenge for energy policymakers is to integrate an understanding of impact dynamics into the economic dynamics of energy supply and demand. The challenges of dynamic analysis of emissions impacts from the energy sector have substantially increased with a new

260

Automatic Reconstruction of Fault Networks from Seismicity Catalogs: 3D Optimal Anisotropic Dynamic Clustering  

E-Print Network (OSTI)

We propose a new pattern recognition method that is able to reconstruct the 3D structure of the active part of a fault network using the spatial location of earthquakes. The method is a generalization of the so-called dynamic clustering method, that originally partitions a set of datapoints into clusters, using a global minimization criterion over the spatial inertia of those clusters. The new method improves on it by taking into account the full spatial inertia tensor of each cluster, in order to partition the dataset into fault-like, anisotropic clusters. Given a catalog of seismic events, the output is the optimal set of plane segments that fits the spatial structure of the data. Each plane segment is fully characterized by its location, size and orientation. The main tunable parameter is the accuracy of the earthquake localizations, which fixes the resolution, i.e. the residual variance of the fit. The resolution determines the number of fault segments needed to describe the earthquake catalog, the better...

Ouillon, G; Sornette, D; Ouillon, Guy; Ducorbier, Caroline; Sornette, Didier

2007-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamic optimization model" 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

Complete model of a spherical gravitational wave detector with capacitive transducers. Calibration and sensitivity optimization  

E-Print Network (OSTI)

We report the results of a detailed numerical analysis of a real resonant spherical gravitational wave antenna operating with six resonant two-mode capacitive transducers read out by superconducting quantum interference devices (SQUID) amplifiers. We derive a set of equations to describe the electro-mechanical dynamics of the detector. The model takes into account the effect of all the noise sources present in each transducer chain: the thermal noise associated with the mechanical resonators, the thermal noise from the superconducting impedance matching transformer, the back-action noise and the additive current noise of the SQUID amplifier. Asymmetries in the detector signal-to-noise ratio and bandwidth, coming from considering the transducers not as point-like objects but as sensor with physically defined geometry and dimension, are also investigated. We calculate the sensitivity for an ultracryogenic, 30 ton, 2 meter in diameter, spherical detector with optimal and non-optimal impedance matching of the electrical read-out scheme to the mechanical modes. The results of the analysis is useful not only to optimize existing smaller mass spherical detector like MiniGrail, in Leiden, but also as a technological guideline for future massive detectors. Furthermore we calculate the antenna patterns when the sphere operates with one, three and six resonators. The sky coverage for two detectors based in The Netherlands and Brasil and operating in coincidence is also estimated. Finally, we describe and numerically verify a calibration and filtering procedure useful for diagnostic and detection purposes in analogy with existing resonant bar detectors.

Luciano Gottardi

2006-08-20T23:59:59.000Z

262

Kinetic modeling and automated optimization in microreactor systems  

E-Print Network (OSTI)

The optimization, kinetic investigation, or scale-up of a reaction often requires significant time and materials. Silicon microreactor systems have been shown advantageous for studying chemical reactions due to their small ...

Moore, Jason Stuart

2013-01-01T23:59:59.000Z

263

Modeling and Optimization for Transportation Systems Planning and Operations  

E-Print Network (OSTI)

In this paper, we focus on a number of applications of network optimization techniques to transportation systems analysis. In particular, network analysis problems, network design problems, and network management problems ...

Gartner, Nathan H.

264

Origins of Model–Data Discrepancies in Optimal Fingerprinting  

Science Conference Proceedings (OSTI)

Two approaches to distinguishing anthropogenic greenhouse gas and sulfate aerosol signals in the observed surface temperature record are compared. Both rely on a variant of general regression called “optimal fingerprinting.” One approach is ...

Gabriele C. Hegerl; Myles R. Allen

2002-06-01T23:59:59.000Z

265

ERCOT's Dynamic Model of Wind Turbine Generators: Preprint  

DOE Green Energy (OSTI)

By the end of 2003, the total installed wind farm capacity in the Electric Reliability Council of Texas (ERCOT) system was approximately 1 gigawatt (GW) and the total in the United States was about 5 GW. As the number of wind turbines installed throughout the United States increases, there is a greater need for dynamic wind turbine generator models that can properly model entire power systems for different types of analysis. This paper describes the ERCOT dynamic models and simulations of a simple network with different types of wind turbine models currently available.

Muljadi, E.; Butterfield, C. P.; Conto, J.; Donoho, K.

2005-08-01T23:59:59.000Z

266

Modeling dynamic diurnal patterns in high frequency financial data  

E-Print Network (OSTI)

-t-EGARCH and can be used to contribute to studies of high-frequency asset returns including the seminal paper by Andersen and Bollerslev (1998). Although we use the DCS model as a vehicle for illustrating the usefulness of the dynamic cubic spline for high... ) independently study decomposition models for estimating the conditional dynamics of p via the logit link. An interesting extension of our model is a hybrid spline-DCS model 7The unconditional nth moment of X is well-defined as long as it is well-defined for F...

Ito, Ryoko

2013-04-19T23:59:59.000Z

267

Thermodynamic modeling and optimization of a screw compressor chiller and cooling tower system  

E-Print Network (OSTI)

This thesis presents a thermodynamic model for a screw chiller and cooling tower system for the purpose of developing an optimized control algorithm for the chiller plant. The thermodynamic chiller model is drawn from the thermodynamic models developed by Gordon and Ng (1996). However, the entropy production in the compressor is empirically related to the pressure difference measured across the compressor. The thermodynamic cooling tower model is the Baker & Shryock cooling tower model that is presented in ASHRAE Handbook - HVAC Systems and Equipment (1992). The models are coupled to form a chiller plant model which can be used to determine the optimal performance. Two correlations are then required to optimize the system: a wet-bulb/setpoint correlation and a fan speed/pump speed correlation. Using these correlations, a "quasi-optimal" operation can be achieved which will save 17% of the energy consumed by the chiller plant.

Graves, Rhett David

2003-12-01T23:59:59.000Z

268

Engine spray combustion modeling using unified spray model with dynamic mesh refinement.  

E-Print Network (OSTI)

??The primary objective of this study is to improve the spray and combustion modeling of internal combustion engines using dynamic mesh refinement. The first part… (more)

Kolakaluri, Ravi

2009-01-01T23:59:59.000Z

269

Dynamic modeling of a single-stage downward firing, entrained flow gasifier  

SciTech Connect

The gasifier is the heart of the integrated gasification combined cycle (IGCC), a technology that has emerged as an attractive alternative to conventional coal-fired power plant technology due to its higher efficiency and cleaner environmental performance especially with the option of CO{sub 2} capture and sequestration. Understanding the optimal performance of the gasifier is therefore paramount for the efficient operation of IGCC power plants. Numerous gasifier models of varying complexity have been developed to study the various aspects of gasifier performance. These range from simple one-dimensional (1D) process-type models to rigorous higher order 2-3D models based on computational fluid dynamics (CFD). Whereas high-fidelity CFD models can accurately predict most key aspects of gasifier performance, they are computationally expensive and typically take hours to days to execute on high-performance computers. Therefore, faster 1D partial differential equation (PDE)-based models are required for use in dynamic simulation studies, control system analysis, and training applications. A number of 1D gasifier models can be found in the literature, but most are steady-state models that have limited application in the practical operation of the gasifier. As a result, 1D PDE-based dynamic models are needed to further study and predict gasifier performance under a wide variety of process conditions and disturbances. In the current study, a 1D transient model of a single-stage downward-fired GE/Texaco-type entrained-flow gasifier has been developed. The model comprises mass, momentum and energy balances for the gas and solid phases. The model considers the initial gasification processes of water evaporation and coal devolatilization. In addition, the key heterogeneous and homogeneous chemical reactions have been modeled. The resulting time-dependent PDE model is solved using the well-known method of lines approach in Aspen Custom Modeler®, whereby the PDEs in the spatial domain are discretized and the resulting differential algebraic equations (DAEs) are then integrated over time using a dynamic integrator. The dynamic response results of the gasifier performance parameters to certain disturbances commonly encountered during practical operation are presented. These disturbances include ramp and step changes to input variables such as coal flow rate, oxygen-to-coal ratio and water-to-coal ratio among others. Comparison of model predictions to available dynamic data will also be discussed.

Kasule, J., Turton, R., Bhattacharyya, D., Zitney, S.

2012-01-01T23:59:59.000Z

270

Identification and modeling for non-linear dynamic system using neural networks type MLP  

Science Conference Proceedings (OSTI)

In control systems, the model dynamics of linear systems is the principal and most important phase of a project, but when working with dynamic of non-linear systems obtain the model becomes a very complex task can be used techniques of system identification. ... Keywords: LP, algorithms, dynamic backprogation, modeling, multilayer perceptrons, neural networks dynamics, non-linear dynamics, training

Hernán González Acuña; Max Suell Dutra; Omar Lengerke

2009-06-01T23:59:59.000Z

271

DYNAMICAL MODEL OF AN EXPANDING SHELL  

Science Conference Proceedings (OSTI)

Expanding blast waves are ubiquitous in many astronomical sources, such as supernova remnants, X-ray emitting binaries, and gamma-ray bursts. I consider here the dynamics of such an expanding blast wave, both in the adiabatic and the radiative regimes. As the blast wave collects material from its surroundings, it decelerates. A full description of the temporal evolution of the blast wave requires consideration of both the energy density and the pressure of the shocked material. The obtained equation is different from earlier works in which only the energy was considered. The solution converges to the familiar results in both the ultrarelativistic and the sub-relativistic (Newtonian) regimes.

Pe'er, Asaf [Harvard-Smithsonian Center for Astrophysics, MS-51, 60 Garden Street, Cambridge, MA 02138 (United States)

2012-06-10T23:59:59.000Z

272

Dynamic language modeling for European Portuguese  

Science Conference Proceedings (OSTI)

This paper reports on the work done on vocabulary and language model daily adaptation for a European Portuguese broadcast news transcription system. The proposed adaptation framework takes into consideration European Portuguese language characteristics, ... Keywords: Automatic speech recognition (ASR), Broadcast news transcription, Information retrieval techniques, Language modeling, Vocabulary selection

Ciro Martins; António Teixeira; João Neto

2010-10-01T23:59:59.000Z

273

Modeling Shapes and Dynamics of Confined Bubbles  

E-Print Network (OSTI)

section used in microfluidic devices or very complex geometries found in disordered materials. To provide of Mechanical Engineering, University of California, Santa Barbara, California 93106-5070; email: bud@engineering cannot be explained by two-phase flow models in circular capillaries. These models also cannot accurately

Ajaev, Vladimir

274

Modeling and simulation of consumer response to dynamic pricing.  

Science Conference Proceedings (OSTI)

Assessing the impacts of dynamic-pricing under the smart grid concept is becoming extremely important for deciding its full deployment. In this paper, we develop a model that represents the response of consumers to dynamic pricing. In the model, consumers use forecasted day-ahead prices to shift daily energy consumption from hours when the price is expected to be high to hours when the price is expected to be low while maintaining the total energy consumption as unchanged. We integrate the consumer response model into the Electricity Market Complex Adaptive System (EMCAS). EMCAS is an agent-based model that simulates restructured electricity markets. We explore the impacts of dynamic-pricing on price spikes, peak demand, consumer energy bills, power supplier profits, and congestion costs. A simulation of an 11-node test network that includes eight generation companies and five aggregated consumers is performed for a period of 1 month. In addition, we simulate the Korean power system.

Valenzuela, J.; Thimmapuram, P.; Kim, J (Decision and Information Sciences); (Auburn Univ.)

2012-08-01T23:59:59.000Z

275

Assessing the reliability of linear dynamic transformer thermal modelling  

E-Print Network (OSTI)

Assessing the reliability of linear dynamic transformer thermal modelling X. Mao, D.J. Tylavsky and G.A. McCulla Abstract: Improving the utilisation of transformers requires that the hot-spot and top. An alternative method for assessing transformer model reliability is provided. 1 Introduction The maximally

276

Modeling dynamic developable meshes by the Hamilton principle  

Science Conference Proceedings (OSTI)

In this paper, a new dynamic developable surface model is proposed. The proposed model represents developable surfaces using triangle meshes. A novel algorithm is proposed to introduce the Hamilton principle into these meshes such that the resulting ... Keywords: Developable surface, Hamilton principle, Physical-based simulation

Yong-Jin Liu; Kai Tang; Ajay Joneja

2007-09-01T23:59:59.000Z

277

DYNASTORE - A Computer Model for Quantifying Dynamic Energy Storage Benefits  

Science Conference Proceedings (OSTI)

Now in development, the DYNASTORE computer model is the first production cost model designed to accurately represent changes in the utility daily load. By quantifying the dynamic benefits of energy storage, it highlights the significant cost savings linked with this technology.

1987-12-16T23:59:59.000Z

278

Wind turbine control systems: Dynamic model development using system identification and the fast structural dynamics code  

DOE Green Energy (OSTI)

Mitigating the effects of damaging wind turbine loads and responses extends the lifetime of the turbine and, consequently, reduces the associated Cost of Energy (COE). Active control of aerodynamic devices is one option for achieving wind turbine load mitigation. Generally speaking, control system design and analysis requires a reasonable dynamic model of {open_quotes}plant,{close_quotes} (i.e., the system being controlled). This paper extends the wind turbine aileron control research, previously conducted at the National Wind Technology Center (NWTC), by presenting a more detailed development of the wind turbine dynamic model. In prior research, active aileron control designs were implemented in an existing wind turbine structural dynamics code, FAST (Fatigue, Aerodynamics, Structures, and Turbulence). In this paper, the FAST code is used, in conjunction with system identification, to generate a wind turbine dynamic model for use in active aileron control system design. The FAST code is described and an overview of the system identification technique is presented. An aileron control case study is used to demonstrate this modeling technique. The results of the case study are then used to propose ideas for generalizing this technique for creating dynamic models for other wind turbine control applications.

Stuart, J.G.; Wright, A.D.; Butterfield, C.P.

1996-10-01T23:59:59.000Z

279

Application of a Dynamic Fuzzy Search Algorithm to Determine Optimal Wind Plant Sizes and Locations in Iowa  

DOE Green Energy (OSTI)

This paper illustrates a method for choosing the optimal mix of wind capacity at several geographically dispersed locations. The method is based on a dynamic fuzzy search algorithm that can be applied to different optimization targets. We illustrate the method using two objective functions for the optimization: maximum economic benefit and maximum reliability. We also illustrate the sensitivity of the fuzzy economic benefit solutions to small perturbations of the capacity selections at each wind site. We find that small changes in site capacity and/or location have small effects on the economic benefit provided by wind power plants. We use electric load and generator data from Iowa, along with high-quality wind-speed data collected by the Iowa Wind Energy Institute.

Milligan, M. R., National Renewable Energy Laboratory; Factor, T., Iowa Wind Energy Institute

2001-09-21T23:59:59.000Z

280

Highly Efficient Modeling of Dynamic Coronal Loops  

E-Print Network (OSTI)

Observational and theoretical evidence suggests that coronal heating is impulsive and occurs on very small cross-field spatial scales. A single coronal loop could contain a hundred or more individual strands that are heated quasi-independently by nanoflares. It is therefore an enormous undertaking to model an entire active region or the global corona. Three-dimensional MHD codes have inadequate spatial resolution, and 1D hydro codes are too slow to simulate the many thousands of elemental strands that must be treated in a reasonable representation. Fortunately, thermal conduction and flows tend to smooth out plasma gradients along the magnetic field, so "0D models" are an acceptable alternative. We have developed a highly efficient model called Enthalpy-Based Thermal Evolution of Loops (EBTEL) that accurately describes the evolution of the average temperature, pressure, and density along a coronal strand. It improves significantly upon earlier models of this type--in accuracy, flexibility, and capability. It ...

Klimchuk, J A; Cargill, P J

2007-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamic optimization model" 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

Dynamic Stabilization of Atmospheric Single Column Models  

Science Conference Proceedings (OSTI)

Single column models (SCMs) provide an economical framework for assessing the sensitivity of atmospheric temperature and humidity to natural and imposed perturbations, and also for developing improved representations of diabatic processes in ...

John W. Bergman; Prashant D. Sardeshmukh

2004-03-01T23:59:59.000Z

282

A Hypergraph Framework for Optimal Model-Based Decomposition ofDesign Problems  

Science Conference Proceedings (OSTI)

Decomposition of large engineering system models is desirable since increased model size reduces reliability and speed of numerical solution algorithms. The article presents a methodology for optimal model-based decomposition (OMBD) of design problems, ... Keywords: decomposition, hypergraph partitioning, large-scale design, model decomposition, multidisciplinary design

Nestor F. Michelena; Panos Y. Papalambros

1997-09-01T23:59:59.000Z

283

Hybrid search algorithm to optimize scheduling problems for TCPN models  

Science Conference Proceedings (OSTI)

Scheduling of manufacturing or logistic processes takes high importance as a key factor to improve competitiveness in industrial systems. The state space analysis of Timed Coloured Petri Nets is an accepted simulation-optimization approach which suffers ... Keywords: decision support systems, discrete event systems, scheduling, state space, timed coloured Petri nets

Miguel Mujica; Miquel Angel Piera

2010-07-01T23:59:59.000Z

284

Modeling and optimization of stencil printing operations: A comparison study  

Science Conference Proceedings (OSTI)

This paper presents a comparison study for the optimization of stencil printing operations using hybrid intelligence technique and response surface methodology (RSM). An average 60% of soldering defects are attributed to solder paste stencil printing ... Keywords: DPMO, Fuzzy quality loss function, Genetic algorithms, Neural network, Printed circuit board, Stencil printing, Surface mount technology

Tsung-Nan Tsai

2008-04-01T23:59:59.000Z

285

Buffer memory optimization for video codec application modeled in Simulink  

Science Conference Proceedings (OSTI)

Reduction of the on-chip memory size is a key issue in video codec system design. Because video codec applications involve complex algorithms that are both data-intensive and control-dependent, memory optimization based on global and precise analysis ... Keywords: Simulink, memory size reduction, video codec application

Sang-Il Han; Xavier Guerin; Soo-Ik Chae; Ahmed A. Jerraya

2006-07-01T23:59:59.000Z

286

A novel decomposition and distributed computing approach for the solution of large scale optimization models  

Science Conference Proceedings (OSTI)

Abstract: Biomass feedstock production is an important component of the biomass based energy sector. Seasonal and distributed collection of low energy density material creates unique challenges, and optimization of the complete value chain is critical ... Keywords: Agent-based modeling, Biomass feedstock, Computation, Decomposition, Optimization

Yogendra Shastri; Alan Hansen; Luis Rodríguez; K. C. Ting

2011-03-01T23:59:59.000Z

287

The New Optimal Model and Realizing of Automatic Rubber Ball Cleaning System for Condenser  

Science Conference Proceedings (OSTI)

An optimal model of rubber ball cleaning system for condenser is proposed in this paper. Based on on-line measurement of fouling resistance, the fouling growth time (set as cleaning time interval in this paper) is fixed and the best running time of rubber ... Keywords: fouling resistance, optimal mode, rubber ball cleaning system for condenser, system realizing

Gong Wang; Yi Xia

2011-08-01T23:59:59.000Z

288

MathematicalGeology, Vol. 11,No. I,1979 Modeling and Optimizing a Gas-Water Reservoir  

E-Print Network (OSTI)

Recovery with waterflooding'*- Mark E.Johnson,2EllisA. Mona&: and Michael S. Watermad Accepted practice the optimal production strategy. Essentially, this strategy is to refrain from waterflooding until the minimum strategy to be optimal. THE GAS-WATERFLOOD RESERVOIR MODEL The mathematical details of the gas-waterflood

Waterman, Michael S.

289

Sensitivity Properties of a Biosphere Model Based on BATS and a Statistical-Dynamical Climate Model  

Science Conference Proceedings (OSTI)

A biosphere model based on the Biosphere-Atmosphere Transfer Scheme (BATS) and the Saltzman-Vernekar (SV) statistical-dynamical climate model is developed. Some equations of BATS are adopted either intact or with modifications, some are ...

Taiping Zhang

1994-06-01T23:59:59.000Z

290

Clustering Properties of Dynamical Dark Energy Models  

E-Print Network (OSTI)

We provide a generic but physically clear discussion of the clustering properties of dark energy models. We explicitly show that in quintessence-type models the dark energy fluctuations, on scales smaller than the Hubble radius, are of the order of the perturbations to the Newtonian gravitational potential, hence necessarily small on cosmological scales. Moreover, comparable fluctuations are associated with different gauge choices. We also demonstrate that the often used homogeneous approximation is unrealistic, and that the so-called dark energy mutation is a trivial artifact of an effective, single fluid description. Finally, we discuss the particular case where the dark energy fluid is coupled to dark matter.

P. P. Avelino; L. M. G. Beca; C. J. A. P. Martins

2008-02-01T23:59:59.000Z

291

A dynamic model of industrial energy demand in Kenya  

Science Conference Proceedings (OSTI)

This paper analyses the effects of input price movements, technology changes, capacity utilization and dynamic mechanisms on energy demand structures in the Kenyan industry. This is done with the help of a variant of the second generation dynamic factor demand (econometric) model. This interrelated disequilibrium dynamic input demand econometric model is based on a long-term cost function representing production function possibilities and takes into account the asymmetry between variable inputs (electricity, other-fuels and Tabour) and quasi-fixed input (capital) by imposing restrictions on the adjustment process. Variations in capacity utilization and slow substitution process invoked by the relative input price movement justifies the nature of input demand disequilibrium. The model is estimated on two ISIS digit Kenyan industry time series data (1961 - 1988) using the Iterative Zellner generalized least square method. 31 refs., 8 tabs.

Haji, S.H.H. [Gothenburg Univ. (Sweden)

1994-12-31T23:59:59.000Z

292

Salt concentration gradient solar ponds: modeling and optimization  

DOE Green Energy (OSTI)

A computer simulation design tool has been developed to simulate dynamic thermal performance for salinity gradient solar ponds. This program will be available to the public through the SERI Solar Analysis Methods Center. Dynamic programming techniques are applied to allow significant user flexibility in analyzing pond performance under realistic load and weather conditions. Finite element techniques describe conduction heat transfer through the pond, earth, and edges. Results are presented that illustrate typical thermal performance of salinity gradient ponds. Sensitivity studies of salty pond thermal performance with respect to geometry, load, and optical transmission are included.

Jayadev, T. S.; Henderson, J.

1979-01-01T23:59:59.000Z

293

Exploring the Modeling Capacity of Two-stage Robust Optimization  

E-Print Network (OSTI)

Jun 13, 2013 ... Numerical experiments on those models are performed using a practical data set, which illustrate their modeling strength, economic outcomes ...

294

Highly Efficient Modeling of Dynamic Coronal Loops  

E-Print Network (OSTI)

Observational and theoretical evidence suggests that coronal heating is impulsive and occurs on very small cross-field spatial scales. A single coronal loop could contain a hundred or more individual strands that are heated quasi-independently by nanoflares. It is therefore an enormous undertaking to model an entire active region or the global corona. Three-dimensional MHD codes have inadequate spatial resolution, and 1D hydro codes are too slow to simulate the many thousands of elemental strands that must be treated in a reasonable representation. Fortunately, thermal conduction and flows tend to smooth out plasma gradients along the magnetic field, so "0D models" are an acceptable alternative. We have developed a highly efficient model called Enthalpy-Based Thermal Evolution of Loops (EBTEL) that accurately describes the evolution of the average temperature, pressure, and density along a coronal strand. It improves significantly upon earlier models of this type--in accuracy, flexibility, and capability. It treats both slowly varying and highly impulsive coronal heating; it provides the differential emission measure distribution, DEM(T), at the transition region footpoints; and there are options for heat flux saturation and nonthermal electron beam heating. EBTEL gives excellent agreement with far more sophisticated 1D hydro simulations despite using four orders of magnitude less computing time. It promises to be a powerful new tool for solar and stellar studies.

J. A. Klimchuk; S. Patsourakos; P. J. Cargill

2007-10-01T23:59:59.000Z

295

Using Evolution Strategy with Meta-models for Well Placement Optimization  

E-Print Network (OSTI)

Optimum implementation of non-conventional wells allows us to increase considerably hydrocarbon recovery. By considering the high drilling cost and the potential improvement in well productivity, well placement decision is an important issue in field development. Considering complex reservoir geology and high reservoir heterogeneities, stochastic optimization methods are the most suitable approaches for optimum well placement. This paper proposes an optimization methodology to determine optimal well location and trajectory based upon the Covariance Matrix Adaptation - Evolution Strategy (CMA-ES) which is a variant of Evolution Strategies recognized as one of the most powerful derivative-free optimizers for continuous optimization. To improve the optimization procedure, two new techniques are investigated: (1). Adaptive penalization with rejection is developed to handle well placement constraints. (2). A meta-model, based on locally weighted regression, is incorporated into CMA-ES using an approximate ranking ...

Bouzarkouna, Zyed; Auger, Anne

2010-01-01T23:59:59.000Z

296

An optimization-model-based interactive decision support system for regional energy management systems planning under uncertainty  

Science Conference Proceedings (OSTI)

In this study, an interactive decision support system (UREM-IDSS) has been developed based on an inexact optimization model (UREM, University of Regina Energy Model) to aid decision makers in planning energy management systems. Optimization modeling, ... Keywords: Decision making, Energy management systems, Green house gas, Interactive decision support system, Optimization, Sustainable development, Uncertainty

Y. P. Cai; G. H. Huang; Q. G. Lin; X. H. Nie; Q. Tan

2009-03-01T23:59:59.000Z

297

E-AMOM: An Energy-Aware Modeling and Optimization Methodology for Scientific Applications on Multicore Systems  

E-Print Network (OSTI)

Power consumption is an important constraint in achieving efficient execution on High Performance Computing Multicore Systems. As the number of cores available on a chip continues to increase, the importance of power consumption will continue to grow. In order to achieve improved performance on multicore systems scientific applications must make use of efficient methods for reducing power consumption and must further be refined to achieve reduced execution time. In this dissertation, we introduce a performance modeling framework, E-AMOM, to enable improved execution of scientific applications on parallel multicore systems with regards to a limited power budget. We develop models for each application based upon performance hardware counters. Our models utilize different performance counters for each application and for each performance component (runtime, system power consumption, CPU power consumption, and memory power consumption) that are selected via our performance-tuned principal component analysis method. Models developed through E-AMOM provide insight into the performance characteristics of each application that affect performance for each component on a parallel multicore system. Our models are more than 92% accurate across both Hybrid (MPI/OpenMP) and MPI implementations for six scientific applications. E-AMOM includes an optimization component that utilizes our models to employ run-time Dynamic Voltage and Frequency Scaling (DVFS) and Dynamic Concurrency Throttling to reduce power consumption of the scientific applications. Further, we optimize our applications based upon insights provided by the performance models to reduce runtime of the applications. Our methods and techniques are able to save up to 18% in energy consumption for Hybrid (MPI/OpenMP) and MPI scientific applications and reduce the runtime of the applications up to 11% on parallel multicore systems.

Lively, Charles

2012-05-01T23:59:59.000Z

298

Optimal numerical realization of the energy balance equation for wind wave models  

Science Conference Proceedings (OSTI)

The optimal numerical realization of the energy balance equation in wind wave models is proposed. The scheme is separated into two parts: the numerical source term integration and the energy propagation numerical realization. The first one is based on ...

Igor V. Lavrenov

2003-06-01T23:59:59.000Z

299

Application of computational intelligence in modeling and optimization of HVAC systems.  

E-Print Network (OSTI)

?? HVAC (Heating Ventilating and Air-Conditioning) system is multivariate, nonlinear, and shares time-varying characteristics. It poses challenges for both system modeling and performance optimization. Traditional… (more)

Li, Mingyang

2009-01-01T23:59:59.000Z

300

The Application of an Evolutionary Algorithm to the Optimization of a Mesoscale Meteorological Model  

Science Conference Proceedings (OSTI)

It is shown that a simple evolutionary algorithm can optimize a set of mesoscale atmospheric model parameters with respect to agreement between the mesoscale simulation and a limited set of synthetic observations. This is illustrated using the ...

Lance O’Steen; David Werth

2009-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamic optimization model" 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

Design optimization and analysis of coated particle fuel using advanced fuel performance modeling techniques  

E-Print Network (OSTI)

Modifying material properties provides another approach to optimize coated particle fuel used in pebble bed reactors. In this study, the MIT fuel performance model (TIMCOAT) was applied after benchmarking against the ...

Soontrapa, Chaiyod

2005-01-01T23:59:59.000Z

302

Sparse Models and Methods for Optimal Instruments with an Application to Eminent Domain  

E-Print Network (OSTI)

We develop results for the use of LASSO and Post-LASSO methods to form first-stage predictions and estimate optimal instruments in linear instrumental variables (IV) models with many instruments, p, that apply even when p ...

Belloni, Alexandre

2011-07-12T23:59:59.000Z

303

Molecular dynamics study of sodium using a model pseudopotential  

Science Conference Proceedings (OSTI)

The dynamics of sodium is investigated using the coulomb and Born-Mayer interaction augmented by a model pseudopotential to represent the electron interactions including screening, exchange, and correlation. The model parameters were previously determined and have been shown to accurately reproduce experimental equation-of-state, lattice vibration, and crystal phase properties of sodium in the harmonic limit. In this paper the equation-of-state and structural properties are examined in molecular dynamics calculations. The long range effects of the potential are included. Typically, each particle interacts with about 500 neighbors. The calculated equation of state of sodium in the hcp, bcc, and liquid structures is discussed.

Swanson, R.E.; Straub, G.K.; Holian, B.L.

1981-01-01T23:59:59.000Z

304

Modeling, simulation, sensitivity analysis, and optimization of hybrid systems  

Science Conference Proceedings (OSTI)

Hybrid (discrete/continuous) systems exhibit both discrete state and continuous state dynamics which interact to such a significant extent that they cannot be decoupled and must be analyzed simultaneously. We present an overview of the work that has ... Keywords: Hybrid automata, combined discrete/continuous simulation, consistent reinitialization, discontinuities, sensitivity analysis, state events, transitions

Paul I. Barton; Cha Kun Lee

2002-10-01T23:59:59.000Z

305

Modeling, Optimization and Economic Evaluation of Residual Biomass Gasification  

E-Print Network (OSTI)

Gasification is a thermo-chemical process which transforms biomass into valuable synthesis gas. Integrated with a biorefinery it can address the facility’s residue handling challenges and input demands. A number of feedstock, technology, oxidizer and product options are available for gasification along with combinations thereof. The objective of this work is to create a systematic method for optimizing the design of a residual biomass gasification unit. In detail, this work involves development of an optimization superstructure, creation of a biorefining scenario, process simulation, equipment sizing & costing, economic evaluation and optimization. The superstructure accommodates different feedstocks, reactor technologies, syngas cleaning options and final processing options. The criterion for optimization is annual worth. A biorefining scenario for the production of renewable diesel fuel from seed oil is developed; gasification receives the residues from this biorefinery. Availability of Soybeans, Jatropha, Chinese Tallow and woody biomass material is set by land use within a 50-mile radius. Four reactor technologies are considered, based on oxidizer type and operating pressure, along with three syngas cleaning methods and five processing options. Results show that residual gasification is profitable for large-scale biorefineries with the proper configuration. Low-pressure air gasification with filters, water-gas shift and hydrogen separation is the most advantageous combination of technology and product with an annual worth of $9.1 MM and a return on investment of 10.7 percent. Low-pressure air gasification with filters and methanol synthesis is the second most advantageous combination with an annual worth of $9.0 MM. Gasification is more economic for residue processing than combustion or disposal, and it competes well with natural gas-based methanol synthesis. However, it is less economic than steam-methane reforming of natural gas to hydrogen. Carbon dioxide credits contribute to profitability, affecting some configurations more than others. A carbon dioxide credit of $33/t makes the process competitive with conventional oil and gas development. Sensitivity analysis demonstrates a 10 percent change in hydrogen or electricity price results in a change to the optimal configuration of the unit. Accurate assessment of future commodity prices is critical to maximizing profitability.

Georgeson, Adam

2010-12-01T23:59:59.000Z

306

Code Reordering and Speculation Support for Dynamic Optimization Systems Erik M. Nystrom, Ronald D. Barnes, Matthew C. Merten, Wen-mei W. Hwu  

E-Print Network (OSTI)

ARchitecture, or ROAR, to support aggressive dynamic optimization of programs. It utilizes a hardware mechanism-flow instructions. Instructions cannot be safely hoisted above conditional branches if their destination registers

Hwu, Wen-mei W.

307

Towards Dynamic Pricing-Based Collaborative Optimizations for Green Data Centers  

E-Print Network (OSTI)

by data center operations. The next-generation Smart Grid proposes to combat the current electrical grid the information exchange framework for utilities and data centers and employ a distributed constraint optimization.S. electricity use [4]. Meanwhile, a sea change in our nation's power distribution network should not be ignored

Plotkin, Joshua B.

308

Modeling of EOG and electrode position optimization for human-computer interface  

Science Conference Proceedings (OSTI)

The aim of this work was to model electro-oculogram (EOG) to find optimal electrode positions for wearable human-computer interface system. The system is a head cap developed in our institute and with it we can measure EOG and facial electromyography ... Keywords: EOG, electrode positions, modeling, volume conductor model

Niina Nöjd; Jari Hyttinen

2008-03-01T23:59:59.000Z

309

Quantification, Optimization and Uncertainty Modeling in Information Security Risks: A Matrix-Based Approach  

Science Conference Proceedings (OSTI)

In this paper, the authors present a quantitative model for estimating security risk exposure for a firm. The model includes a formulation for the optimization of controls as well as determining sensitivity of the exposure of assets to different threats. ... Keywords: Cost Benefit Analysis, Data Simulation, Decision Models, IS Risk Management, Investment Justification, Security Management, Security Risk

Sanjay Goel; Eitel J.M. Lauría

2010-04-01T23:59:59.000Z

310

Dynamic crack initiation toughness : experiments and peridynamic modeling.  

SciTech Connect

This is a dissertation on research conducted studying the dynamic crack initiation toughness of a 4340 steel. Researchers have been conducting experimental testing of dynamic crack initiation toughness, K{sub Ic}, for many years, using many experimental techniques with vastly different trends in the results when reporting K{sub Ic} as a function of loading rate. The dissertation describes a novel experimental technique for measuring K{sub Ic} in metals using the Kolsky bar. The method borrows from improvements made in recent years in traditional Kolsky bar testing by using pulse shaping techniques to ensure a constant loading rate applied to the sample before crack initiation. Dynamic crack initiation measurements were reported on a 4340 steel at two different loading rates. The steel was shown to exhibit a rate dependence, with the recorded values of K{sub Ic} being much higher at the higher loading rate. Using the knowledge of this rate dependence as a motivation in attempting to model the fracture events, a viscoplastic constitutive model was implemented into a peridynamic computational mechanics code. Peridynamics is a newly developed theory in solid mechanics that replaces the classical partial differential equations of motion with integral-differential equations which do not require the existence of spatial derivatives in the displacement field. This allows for the straightforward modeling of unguided crack initiation and growth. To date, peridynamic implementations have used severely restricted constitutive models. This research represents the first implementation of a complex material model and its validation. After showing results comparing deformations to experimental Taylor anvil impact for the viscoplastic material model, a novel failure criterion is introduced to model the dynamic crack initiation toughness experiments. The failure model is based on an energy criterion and uses the K{sub Ic} values recorded experimentally as an input. The failure model is then validated against one class of problems showing good agreement with experimental results.

Foster, John T.

2009-10-01T23:59:59.000Z

311

Pathwise Optimization for Optimal Stopping Problems  

Science Conference Proceedings (OSTI)

We introduce the pathwise optimization (PO) method, a new convex optimization procedure to produce upper and lower bounds on the optimal value (the “price”) of a high-dimensional optimal stopping problem. The PO method builds on a dual characterization ... Keywords: American options, Bermudian options, dynamic programming, optimal control, optimal stopping

Vijay V. Desai; Vivek F. Farias; Ciamac C. Moallemi

2012-12-01T23:59:59.000Z

312

Vorton dynamics: a case study of developing a fluid dynamics model for a vector processor  

Science Conference Proceedings (OSTI)

The raw performance of vector processors such as the CDC CYBER-205 has been well documented. The ability to apply this raw power to ever more complex algebraic algorithms has been reported in [9]. The final step in making computers of this class truly ... Keywords: CYBER-205, computational fluid dynamics, programming, vorton model

M. J. Kascic, Jr.

1984-08-01T23:59:59.000Z

313

Integrated Multi-Well Reservoir and Decision Model to Determine Optimal Well Spacing in Unconventional Gas Reservoirs  

E-Print Network (OSTI)

Optimizing well spacing in unconventional gas reservoirs is difficult due to complex heterogeneity, large variability and uncertainty in reservoir properties, and lack of data that increase the production uncertainty. Previous methods are either suboptimal because they do not consider subsurface uncertainty (e.g., statistical moving-window methods) or they are too time-consuming and expensive for many operators (e.g., integrated reservoir characterization and simulation studies). This research has focused on developing and extending a new technology for determining optimal well spacing in tight gas reservoirs that maximize profitability. To achieve the research objectives, an integrated multi-well reservoir and decision model that fully incorporates uncertainty was developed. The reservoir model is based on reservoir simulation technology coupled with geostatistical and Monte Carlo methods to predict production performance in unconventional gas reservoirs as a function of well spacing and different development scenarios. The variability in discounted cumulative production was used for direct integration of the reservoir model with a Bayesian decision model (developed by other members of the research team) that determines the optimal well spacing and hence the optimal development strategy. The integrated model includes two development stages with a varying Stage-1 time span. The integrated tools were applied to an illustrative example in Deep Basin (Gething D) tight gas sands in Alberta, Canada, to determine optimal development strategies. The results showed that a Stage-1 length of 1 year starting at 160-acre spacing with no further downspacing is the optimal development policy. It also showed that extending the duration of Stage 1 beyond one year does not represent an economic benefit. These results are specific to the Berland River (Gething) area and should not be generalized to other unconventional gas reservoirs. However, the proposed technology provides insight into both the value of information and the ability to incorporate learning in a dynamic development strategy. The new technology is expected to help operators determine the combination of primary and secondary development policies early in the reservoir life that profitably maximize production and minimize the number of uneconomical wells. I anticipate that this methodology will be applicable to other tight and shale gas reservoirs.

Ortiz Prada, Rubiel Paul

2010-12-01T23:59:59.000Z

314

ANL/ALCF/ESP-13/8 Using Multi-scale Dynamic Rupture Models to  

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

Using Multi-scale Dynamic Rupture Models to Improve Ground Motion Estimates PI: Thomas Jordan ESP Postdoc: Geoffrey Ely Science Overview This project uses dynamic rupture...

315

Adaptive fuzzy model based inverse controller design using BB-BC optimization algorithm  

Science Conference Proceedings (OSTI)

The use of inverse system model as a controller might be an efficient way in controlling non-linear systems. It is also a known fact that fuzzy logic modeling is a powerful tool in representing nonlinear systems. Therefore, inverse fuzzy model can be ... Keywords: Big Bang-Big Crunch optimization, Fuzzy logic controller, Fuzzy model inversion, Heat transfer process, Inverse model based control, pH process

Tufan Kumbasar; Ibrahim Eksin; Mujde Guzelkaya; Engin Yesil

2011-09-01T23:59:59.000Z

316

An Optimization Model for Plug-In Hybrid Electric Vehicles  

DOE Green Energy (OSTI)

The necessity for environmentally conscious vehicle designs in conjunction with increasing concerns regarding U.S. dependency on foreign oil and climate change have induced significant investment towards enhancing the propulsion portfolio with new technologies. More recently, plug-in hybrid electric vehicles (PHEVs) have held great intuitive appeal and have attracted considerable attention. PHEVs have the potential to reduce petroleum consumption and greenhouse gas (GHG) emissions in the commercial transportation sector. They are especially appealing in situations where daily commuting is within a small amount of miles with excessive stop-and-go driving. The research effort outlined in this paper aims to investigate the implications of motor/generator and battery size on fuel economy and GHG emissions in a medium-duty PHEV. An optimization framework is developed and applied to two different parallel powertrain configurations, e.g., pre-transmission and post-transmission, to derive the optimal design with respect to motor/generator and battery size. A comparison between the conventional and PHEV configurations with equivalent size and performance under the same driving conditions is conducted, thus allowing an assessment of the fuel economy and GHG emissions potential improvement. The post-transmission parallel configuration yields higher fuel economy and less GHG emissions compared to pre-transmission configuration partly attributable to the enhanced regenerative braking efficiency.

Malikopoulos, Andreas [ORNL; Smith, David E [ORNL

2011-01-01T23:59:59.000Z

317

A theoretical approach for dynamic modelling of sustainable development  

Science Conference Proceedings (OSTI)

This article presents a theoretical model for a dynamic system based on sustainable development. Due to the relatively absence of theoretical studies and practical issues in the area of sustainable development, Romania aspires to the principles of sustainable ... Keywords: economic development, economic system, economic welfare, natural environment, resources scarcity, sustainable development

Corina-Maria Ene; Anda Gheorghiu; Anca Gheorghiu

2011-02-01T23:59:59.000Z

318

Dynamic predication model for integrated series and application  

Science Conference Proceedings (OSTI)

In the paper a predication model for integrated series is proposed. Granger causality analysis is deployed first for finding out the cointegrated series for the interested series. Then granger causality information is used for the identification of the ... Keywords: cointegration series, dynamic prediction, electricity demand, granger causality

Yuan Jia-hai; Zhao Zhi; Xiong Min-peng

2006-11-01T23:59:59.000Z

319

Dynamic world model with the lazy potential function  

Science Conference Proceedings (OSTI)

One of the fundamental skills of an autonomous mobile robot is its ability to determine a collision-free path in a dynamically changing environment. To meet this challenge, robots often have their own world model - an internal representation of the environment. ...

Konrad Ku?akowski; Tomasz St?pie?

2011-06-01T23:59:59.000Z

320

Modelling life cycle and population dynamics of Nostocales (cyanobacteria)  

Science Conference Proceedings (OSTI)

Cyanobacteria of the order Nostocales found in lakes in temperate regions are generally assumed to benefit from climate change. To predict their future development under varying environmental conditions, we developed a mathematical model that simulates ... Keywords: Cylindrospermopsis raciborskii, Hasse diagram, Life cycle, Nostocales, Population dynamics, Shallow lake

K. D. Jöhnk; R. Brüggemann; J. Rücker; B. Luther; U. Simon; B. Nixdorf; C. Wiedner

2011-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamic optimization model" 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

A pseudo-equilibrium thermodynamic model of information processing in nonlinear brain dynamics  

E-Print Network (OSTI)

Haven CT: Yale U. P. Thermodynamic model of brain dynamicsNeurophysiol. 117(3), Thermodynamic model of brain dynamicsA far-from-equilibrium thermodynamic model of the action-

Freeman, Walter J III

2008-01-01T23:59:59.000Z

322

Gauge turbulence, topological defect dynamics, and condensation in Higgs models  

E-Print Network (OSTI)

The real-time dynamics of topological defects and turbulent configurations of gauge fields for electric and magnetic confinement are studied numerically within a 2+1D Abelian Higgs model. It is shown that confinement is appearing in such systems equilibrating after a strong initial quench such as the overpopulation of the infrared modes. While the final equilibrium state does not support confinement, metastable vortex defect configurations appear in the gauge field which are found to be closely related to the appearance of physically observable confined electric and magnetic charges. These phenomena are seen to be intimately related to the approach of a non-thermal fixed point of the far-from-equilibrium dynamical evolution, signalled by universal scaling in the gauge-invariant correlation function of the Higgs field. Even when the parameters of the Higgs action do not support condensate formation in the vacuum, during this approach, transient Higgs condensation is observed. We discuss implications of these results for the far-from-equilibrium dynamics of Yang-Mills fields and potential mechanisms how confinement and condensation in non-abelian gauge fields can be understood in terms of the dynamics of Higgs models. These suggest that there is an interesting new class of dynamics of strong coherent turbulent gauge fields with condensates.

Thomas Gasenzer; Larry McLerran; Jan M. Pawlowski; Dénes Sexty

2013-07-19T23:59:59.000Z

323

Agent-based modeling and systems dynamics model reproduction.  

Science Conference Proceedings (OSTI)

Reproducibility is a pillar of the scientific endeavour. We view computer simulations as laboratories for electronic experimentation and therefore as tools for science. Recent studies have addressed model reproduction and found it to be surprisingly difficult to replicate published findings. There have been enough failed simulation replications to raise the question, 'can computer models be fully replicated?' This paper answers in the affirmative by reporting on a successful reproduction study using Mathematica, Repast and Swarm for the Beer Game supply chain model. The reproduction process was valuable because it demonstrated the original result's robustness across modelling methodologies and implementation environments.

North, M. J.; Macal, C. M. (Decision and Information Sciences)

2009-01-01T23:59:59.000Z

324

Optimization Online - A stochastic multiscale model for electricity ...  

E-Print Network (OSTI)

May 30, 2011 ... A stochastic multiscale model for electricity generation capacity expansion. Panos Parpas(pparpas ***at*** mit.edu) Mort Webster(mort ***at*** ...

325

Two-stage Models and Algorithms for Optimizing Infrastructure ...  

E-Print Network (OSTI)

Jun 20, 2012 ... Abstract: This paper models an infrastructure as a network with sets of supply, transshipment, and demand nodes. A subset of potential arcs ...

326

Optimization and Modeling of an Emulsion Polymerization Reactor.  

E-Print Network (OSTI)

??A mathematical model was developed to simulate emulsion polymerization in batch, semi-batch and continuous reactors for monomers with high water solubility and significant desorption such… (more)

Ghadi, Narges

2004-01-01T23:59:59.000Z

327

Optimization Online - An Inventory-Location Model: Formulation ...  

E-Print Network (OSTI)

Jun 5, 2001 ... Abstract: We introduce a new distribution center (DC) location model that incorporates working inventory and safety stock inventory costs at the ...

328

Optimization Online - Optimizing Trading Decisions for Hydro ...  

E-Print Network (OSTI)

Dec 10, 2011 ... Optimizing Trading Decisions for Hydro Storage Systems using Approximate ... Keywords: OR in Energy, Approximate Dynamic Programming, ...

329

Neuro-genetic approach to optimize parameter design of dynamic multiresponse experiments  

Science Conference Proceedings (OSTI)

Engineers have widely applied the Taguchi method, a traditional approach for robust experimental design, to a variety of quality engineering problems for enhancing system robustness. However, the Taguchi method is unable to deal with dynamic multiresponse ... Keywords: Dynamic multiresponse, Experimental design, Exponential desirability functions, Genetic algorithms, Neural networks, Taguchi method

Hsu-Hwa Chang; Yan-Kwang Chen

2011-01-01T23:59:59.000Z

330

Posterior Sampling using Particle Swarm Optimizers and Model Reduction Techniques  

Science Conference Proceedings (OSTI)

Inverse problems are ill-posed and posterior sampling is a way of providing an estimate of the uncertainty based on a finite set of the family of models that fit the observed data within the same tolerance. Monte Carlo methods are used for this purpose ... Keywords: High Dimensional Spaces, Inverse Problems, Model Reduction Techniques, Particle Swarm, Posterior Sampling

J. L. Fernández Martínez; E. García Gonzalo; Z. Fernández Muñiz; G. Mariethoz; T. Mukerji

2010-07-01T23:59:59.000Z

331

A framework for modeling payments for ecosystem services with agent-based models, Bayesian belief networks and opinion dynamics models  

Science Conference Proceedings (OSTI)

We present an integrated modeling framework for simulating land-use decision making under the influence of payments for ecosystem services. The model combines agent-based modeling (ABM) with Bayesian belief networks (BBNs) and opinion dynamics models ... Keywords: Agent based modeling, Bayesian network, China, Human-environment interaction, IAMO-LUC, Land use change, Payments for environmental services, Social influence

Zhanli Sun, Daniel MüLler

2013-07-01T23:59:59.000Z

332

Optimal state estimation for improved power measurements and model verification: Theory  

Science Conference Proceedings (OSTI)

To improve energy efficiency in computer systems and data centers, accurate models of the power consumption are needed for analysis and advanced control algorithms. Developing models requires deep understanding not only of the components themselves but ... Keywords: system level model analysis, energy efficiency, optimal state estimation, improved power measurement, computer systems, data centers, power consumption, mathematical methods, sensor fusion, data center powering structure, cooling system, parameter identifying estimator, model parameter

T. Malkamaki; S. J. Ovaska

2011-07-01T23:59:59.000Z

333

A Modeling and Optimization Approach for Multiple Energy Carrier Power Flow  

E-Print Network (OSTI)

Abstract — This paper presents a general power flow and optimization approach for power systems including multiple energy carriers, such as electricity, natural gas, and district heat. The model is based on a conceptual approach for the inclusion of distributed resources. Couplings between the different energy carriers are regarded explicitly, enabling investigations in power flow and marginal price interactions. Optimal demand, conversion, and transmission of multiple energy carriers within a system is formulated as a combined optimal power flow problem. A numerical example demonstrates how the method can be used for different system studies. I.

Martin Geidl; Göran Andersson

2005-01-01T23:59:59.000Z

334

A dynamical model for pion electroproduction on the nucleon  

E-Print Network (OSTI)

We develop a Lorenz- and gauge-invariant dynamical model for pion electroproduction in the resonance region. The model is based on solving of the Salpeter (instantaneous) equation for the pion-nucleon interaction with a hadron-exchange potential. We find that the one-particle-exchange kernel of the Salpeter equation for pion electroproduction develops an unphysical singularity for a finite value of $Q^{2}$. We analyse two methods of dealing with this problem. Results of our model are compared with recent single-polarization data for pion electroproduction.

George L. Caia; Louis E. Wright; Vladimir Pascalutsa

2005-06-02T23:59:59.000Z

335

Interconnect modeling and optimization in deep sub-micron technologies  

E-Print Network (OSTI)

Interconnect will be a major bottleneck for deep sub-micron technologies in the years to come. This dissertation addresses the communication aspect from a power consumption and transmission speed perspective. A model for ...

Sotiriadis, Paul Peter P. (Paul Peter Peter-Paul), 1973-

2002-01-01T23:59:59.000Z

336

Optimally Merging Precipitation to Minimize Land Surface Modeling Errors  

Science Conference Proceedings (OSTI)

This paper introduces a new method to improve land surface model skill by merging different available precipitation datasets, given that an accurate land surface parameter ground truth is available. Precipitation datasets are merged with the ...

M. Tugrul Yilmaz; Paul Houser; Roshan Shrestha; Valentine G. Anantharaj

2010-03-01T23:59:59.000Z

337

State reduction dynamics in a simplified QED model  

E-Print Network (OSTI)

A simplified model of quantum electrodynamics involving a charged two-state system interacting with an electromagnetic field mode is examined. By extending the Schrodinger equation to include stochastic and nonlinear terms the dynamical process of quantum state reduction can be represented. A specific choice of modified Schrodinger dynamics is shown to result in stable coherent field states. The two-state system undergoes an induced state reduction to a generalised current state due to its interaction with the field mode. Numerical results are presented demonstrating state reduction dynamics for an initial superposition of two current states. An induced reduction time-scale for the two-state system is derived and confirmed by the numerics.

D. J. Bedingham

2008-08-29T23:59:59.000Z

338

Structural Modeling and Molecular Dynamics Simulation of the Actin Filament  

DOE Green Energy (OSTI)

Actin is a major structural protein of the eukaryotic cytoskeleton and enables cell motility. Here, we present a model of the actin filament (F-actin) that not only incorporates the global structure of the recently published model by Oda et al. but also conserves internal stereochemistry. A comparison is made using molecular dynamics simulation of the model with other recent F-actin models. A number of structural determents such as the protomer propeller angle, the number of hydrogen bonds, and the structural variation among the protomers are analyzed. The MD comparison is found to reflect the evolution in quality of actin models over the last 6 years. In addition, simulations of the model are carried out in states with both ADP or ATP bound and local hydrogen-bonding differences characterized.

Splettstoesser, Thomas [University of Heidelberg; Holmes, Kenneth [Max Planck Institute, Heidelberg, Germany; Noe, Frank [DFG Research Center Matheon, FU Berlin, Germany; Smith, Jeremy C [ORNL

2011-01-01T23:59:59.000Z

339

A novel combination of Particle Swarm Optimization and Genetic Algorithm for Pareto optimal design of a five-degree of freedom vehicle vibration model  

Science Conference Proceedings (OSTI)

In this paper, at first, a novel combination of Particle Swarm Optimization (PSO) and Genetic Algorithm (GA) is introduced. This hybrid algorithm uses the operators such as mutation, traditional or classical crossover, multiple-crossover, and PSO formula. ... Keywords: Genetic Algorithm, Hybrid algorithms, Multi-objective problems, Particle Swarm Optimization, Single-objective problems, Vehicle vibration model

M. J. Mahmoodabadi; A. Adljooy Safaie; A. Bagheri; N. Nariman-Zadeh

2013-05-01T23:59:59.000Z

340

Solution of Nonlinear Finite Difference Ocean Models by Optimization Methods with Sensitivity and Observational Strategy Analysis  

Science Conference Proceedings (OSTI)

Dynamical models driven by “observed” forcing fields (e.g., the wind) have a true solution uncertainty owing to observational errors in the driving. This uncertainty is usually hidden from view because conventional numerical methods do not easily ...

Jens Schröter; Carl Wunsch

1986-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamic optimization model" 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

A watershed-scale design optimization model for stormwater best management practices  

Science Conference Proceedings (OSTI)

U.S. Environmental Protection Agency developed a decision-support system, System for Urban Stormwater Treatment and Analysis Integration (SUSTAIN), to evaluate alternative plans for stormwater quality management and flow abatement techniques in urban ... Keywords: BMP modeling, Best management practices (BMPs), Cost-effectiveness, Decision-support system, Design optimization model, Green infrastructure (GI), Low impact development (LID), Stormwater management

Joong Gwang Lee; Ariamalar Selvakumar; Khalid Alvi; John Riverson; Jenny X. Zhen; Leslie Shoemaker; Fu-Hsiung Lai

2012-11-01T23:59:59.000Z

342

Modeling and Parameter Optimization for an Articulating Electro Hydraulic Forest Machinery  

Science Conference Proceedings (OSTI)

This paper focuses on modeling and parameter estimation for the electro hydraulic actuation system of an articulated forestry machine. The linear graph method is implemented in deriving mathematical models of the swing, boom and stick subsystems. Actuation ... Keywords: Forest Machinery, Articulating Electro Hydraulic, Parameter Optimization

Wei-Zhan Guo; Liu-Jin Hao; Yu Ying; Wu-Jia Di

2010-01-01T23:59:59.000Z

343

Deterministic regression model and visual basic code for optimal forecasting of financial time series  

Science Conference Proceedings (OSTI)

A new, non-statistical method is presented for analysis of the past history and current evolution of economic and financial processes. The method is based on the sliding model approach using linear differential or difference equations applied to discrete ... Keywords: Optimal forecasting in finance, Sliding deterministic regression models

Alejandro Balbás; Beatriz Balbás; Inna Galperin; Efim Galperin

2008-11-01T23:59:59.000Z

344

Modelling Mediterranean landscape succession-disturbance dynamics: A landscape fire-succession model  

Science Conference Proceedings (OSTI)

We present a spatially explicit Landscape Fire-Succession Model (LFSM) developed to represent Mediterranean Basin landscapes and capable of integrating modules and functions that explicitly represent human activity. Plant-functional types are used to ... Keywords: Landscape fire-succession model, Mediterranean landscape, Pattern-oriented modelling, Succession-disturbance dynamics, Wildfire regime

James D. A. Millington; John Wainwright; George L. W. Perry; Raul Romero-Calcerrada; Bruce D. Malamud

2009-10-01T23:59:59.000Z

345

Dynamic model and estimation of the future eutrophication for the Lake Prespa  

Science Conference Proceedings (OSTI)

This paper presents a new computing analysis, based on Matlab Simulink, how to build a dynamic model for aquatic surface water bodies in our case the Lake Prespa. The dynamic model, which is more complex than the other models, it involves equation that ... Keywords: Lake Prespa, dynamic model, eutrophication, phosphorus concentration, scenario ca, scenario cc

Kosta Mitreski; Andreja Naumoski

2007-05-01T23:59:59.000Z

346

Integrated method to create optimal dynamic strategic plans for corporate technology start-ups  

E-Print Network (OSTI)

This thesis presents an innovative method for evaluating and dynamically planning the development of uncertain technology investments. Its crux centers on a paradigm shift in the way managers assess investments, toward an ...

Mikati, Samir Omar

2009-01-01T23:59:59.000Z

347

Computational fluid dynamic (CFD) optimization of microfluidic mixing in a MEMS steam generator  

E-Print Network (OSTI)

The challenge of achieving rapid mixing in microchannels is addressed through a computational fluid dynamics (CFD) study using the ADINA-F finite element program. The study is motivated by the need to design an adequate ...

Collins, Kimberlee C. (Kimberlee Chiyoko)

2008-01-01T23:59:59.000Z

348

A sniffer technique for an efficient deduction of model dynamical equations using genetic programming  

Science Conference Proceedings (OSTI)

A novel heuristic technique that enhances the search facility of the standard genetic programming (GP) algorithm is presented. The method provides a dynamic sniffing facility to optimize the local search in the vicinity of the current best chromosomes ...

Dilip P. Ahalpara; Abhijit Sen

2011-04-01T23:59:59.000Z

349

Dynamic modeling efforts for system interface studies for nuclear hydrogen production.  

DOE Green Energy (OSTI)

System interface studies require not only identifying economically optimal equipment configurations, which involves studying mainly full power steady-state operation, but also assessing the operability of a design during load change and startup and assessing safety-related behavior during upset conditions. This latter task is performed with a dynamic simulation code. This report reviews the requirements of such a code. It considers the types of transients that will need to be simulated, the phenomena that will be present, the models best suited for representing the phenomena, and the type of numerical solution scheme for solving the models to obtain the dynamic response of the combined nuclear-hydrogen plant. Useful insight into plant transient behavior prior to running a dynamics code is obtained by some simple methods that take into account component time constants and energy capacitances. Methods for determining reactor stability, plant startup time, and temperature response during load change, and tripping of the reactor are described. Some preliminary results are presented.

Vilim, R. B.; Nuclear Engineering Division

2007-08-15T23:59:59.000Z

350

Dynamic Absorption Model for Off-Gas Separation  

Science Conference Proceedings (OSTI)

Modeling and simulations will aid in the future design of U.S. advanced reprocessing plants for the recovery and recycle of actinides in used nuclear fuel. The specific fuel cycle separation process discussed in this report is the off-gas treatment system. The off-gas separation consists of a series of scrubbers and adsorption beds to capture constituents of interest. Dynamic models are being developed to simulate each unit operation involved so each unit operation can be used as a stand-alone model and in series with multiple others. Currently, a rate based, dynamic absorption model is being developed in gPROMS software. Inputs include liquid and gas stream constituents, column properties, liquid and gas phase reactions, number of stages, and inlet conditions. It simulates multiple component absorption with countercurrent flow and accounts for absorption by mass transfer and chemical reaction. The assumption of each stage being a discrete well-mixed entity was made. Therefore, the model is solved stagewise. The simulation outputs component concentrations in both phases as a function of time from which the rate of absorption is determined. Temperature of both phases is output as a function of time also. The model will be used able to be used as a standalone model in addition to in series with other off-gas separation unit operations. The current model is being generated based on NOx absorption; however, a future goal is to develop a CO2 specific model. The model will have the capability to be modified for additional absorption systems. The off-gas models, both adsorption and absorption, will be made available via the server or web for evaluation by customers.

Veronica J. Rutledge

2011-07-01T23:59:59.000Z

351

Stochastic kinetic models: Dynamic independence, modularity and graphs  

E-Print Network (OSTI)

The dynamic properties and independence structure of stochastic kinetic models (SKMs) are analyzed. An SKM is a highly multivariate jump process used to model chemical reaction networks, particularly those in biochemical and cellular systems. We identify SKM subprocesses with the corresponding counting processes and propose a directed, cyclic graph (the kinetic independence graph or KIG) that encodes the local independence structure of their conditional intensities. Given a partition $[A,D,B]$ of the vertices, the graphical separation $A\\perp B|D$ in the undirected KIG has an intuitive chemical interpretation and implies that $A$ is locally independent of $B$ given $A\\cup D$. It is proved that this separation also results in global independence of the internal histories of $A$ and $B$ conditional on a history of the jumps in $D$ which, under conditions we derive, corresponds to the internal history of $D$. The results enable mathematical definition of a modularization of an SKM using its implied dynamics. Gra...

Bowsher, Clive G

2010-01-01T23:59:59.000Z

352

Lessons Learned from Alternative Transportation Fuels: Modeling Transition Dynamics  

Alternative Fuels and Advanced Vehicles Data Center (EERE)

Lessons Learned from Lessons Learned from Alternative Transportation Fuels: Modeling Transition Dynamics C. Welch Technical Report NREL/TP-540-39446 February 2006 Lessons Learned from Alternative Transportation Fuels: Modeling Transition Dynamics C. Welch Prepared under Task Nos. HS04.2000 and HS06.1002 Technical Report NREL/TP-540-39446 February 2006 National Renewable Energy Laboratory 1617 Cole Boulevard, Golden, Colorado 80401-3393 303-275-3000 * www.nrel.gov Operated for the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy by Midwest Research Institute * Battelle Contract No. DE-AC36-99-GO10337 NOTICE This report was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor any agency thereof, nor any of their employees, makes any

353

Façade apertures optimization: integrating cross-ventilation performance analysis in fluid dynamics simulation  

Science Conference Proceedings (OSTI)

Performance-oriented design has as a primary aim to introduce spaces that achieve acceptable levels of human comfort. Wind-induced airflow plays a significant role in the improving occupants' comfort in a building. This paper explores the extent to which ... Keywords: building performance simulation, generative design, multiple criteria optimization, parametric design, wind-induced ventilation

Chrysanthi (Sandy) Karagkouni; Ava Fatah gen Schieck; Martha Tsigkari; Angelos Chronis

2013-04-01T23:59:59.000Z

354

Emissions and Energy: An Integral Approach Using an Online Energy Management and Optimization Model  

E-Print Network (OSTI)

With the expected legislation on the horizon in the U.S., the cost of CO2 emissions will have significant impact on industrial plant operations in the near future. Our purpose in this presentation is to show real industrial examples in which, with the existing equipment, continuous CO2 emissions reductions were achieved while, at the same time, optimizing the energy systems using an online model. We will show the importance of including the cost of CO2 emissions and how they should properly be taken into account when managing energy systems. Furthermore, we will illustrate how an optimization model is used for evaluating case studies to suggest the most cost effective energy system modifications while taking into account CO2 emissions costs. Several examples and results corresponding to the application of such systems to refineries will be discussed. In addition, the integration of CO2 emission costs and constraints into the online energy system models and their optimization is also explained.

Ruiz, D.; Ruiz, C.; Santollani, O.; Reitmeier, T.

2010-01-01T23:59:59.000Z

355

HEURISTIC APPROACH FOR OPTIMAL PARAMETER ESTIMATION OF ELECTRIC LOAD FORECAST MODEL  

Science Conference Proceedings (OSTI)

Load forecasting is a crucial aspect of electric power system planning and operation. This paper presents a heuristic approach for optimal parameter estimation of long term load forecast models. The problem is viewed as an optimization one in which the goal is to minimize the total estimation error by properly adjusting the model coefficients. A particle swarm optimization algorithm is developed to minimize the error associated with the estimated model parameters. Real data of Egyptian network is used to perform this study. Results are reported and compared to those obtained using the well known least error squares estimation technique. Comparison results are in favor of the proposed approach which signifies its potential as a promising estimation tool.

M. R. AlRashidi; K. M. EL?Naggar

2009-01-01T23:59:59.000Z

356

Modeling the dynamic crush of impact mitigating materials  

DOE Green Energy (OSTI)

Crushable materials are commonly utilized in the design of structural components to absorb energy and mitigate shock during the dynamic impact of a complex structure, such as an automobile chassis or drum-type shipping container. The development and application of several finite-element material models which have been developed at various times at LLNL for DYNA3D will be discussed. Between the models, they are able to account for several of the predominant mechanisms which typically influence the dynamic mechanical behavior of crushable materials. One issue we addressed was that no single existing model would account for the entire gambit of constitutive features which are important for crushable materials. Thus, we describe the implementation and use of an additional material model which attempts to provide a more comprehensive model of the mechanics of crushable material behavior. This model combines features of the pre-existing DYNA models and incorporates some new features as well in an invariant large-strain formulation. In addition to examining the behavior of a unit cell in uniaxial compression, two cases were chosen to evaluate the capabilities and accuracy of the various material models in DYNA. In the first case, a model for foam filled box beams was developed and compared to test data from a 4-point bend test. The model was subsequently used to study its effectiveness in energy absorption in an aluminum extrusion, spaceframe, vehicle chassis. The second case examined the response of the AT-400A shipping container and the performance of the overpack material during accident environments selected from 10CFR71 and IAEA regulations.

Logan, R.W.; McMichael, L.D.

1995-05-12T23:59:59.000Z

357

Integrating Flux Balance Analysis into Kinetic Models to Decipher the Dynamic Metabolism of Shewanella oneidensis MR-1  

E-Print Network (OSTI)

Shewanella oneidensis MR-1 sequentially utilizes lactate and its waste products (pyruvate and acetate) during batch culture. To decipher MR-1 metabolism, we integrated genome-scale flux balance analysis (FBA) into a multiple-substrate Monod model to perform the dynamic flux balance analysis (dFBA). The dFBA employed a static optimization approach (SOA) by dividing the batch time into small intervals (i.e.,,400 mini-FBAs), then the Monod model provided time-dependent inflow/ outflow fluxes to constrain the mini-FBAs to profile the pseudo-steady-state fluxes in each time interval. The mini-FBAs used a dual-objective function (a weighted combination of ‘‘maximizing growth rate’ ’ and ‘‘minimizing overall flux’’) to capture trade-offs between optimal growth and minimal enzyme usage. By fitting the experimental data, a bi-level optimization of dFBA revealed that the optimal weight in the dual-objective function was time-dependent: the objective function was constant in the early growth stage, while the functional weight of minimal enzyme usage increased significantly when lactate became scarce. The dFBA profiled biologically meaningful dynamic MR-1 metabolisms: 1. the oxidative TCA cycle fluxes increased initially and then decreased in the late growth stage; 2. fluxes in the pentose phosphate pathway and gluconeogenesis were stable in the exponential growth period; and 3. the glyoxylate shunt was up-regulated when acetate became the main carbon source for MR-1 growth.

Xueyang Feng; You Xu; Yixin Chen; Yinjie J. Tang

2011-01-01T23:59:59.000Z

358

A Dissipative-Particle-Dynamics Model for Simulating Dynamics of Charged Colloid  

E-Print Network (OSTI)

A mesoscopic colloid model is developed in which a spherical colloid is represented by many interacting sites on its surface. The hydrodynamic interactions with thermal fluctuations are taken accounts in full using Dissipative Particle Dynamics, and the electrostatic interactions are simulated using Particle-Particle-Particle Mesh method. This new model is applied to investigate the electrophoretic mobility of a charged colloid under an external electric field, and the influence of salt concentration and colloid charge are systematically studied. The simulation results show good agreement with predictions from the electrokinetic theory.

Jiajia Zhou; Friederike Schmid

2013-11-05T23:59:59.000Z

359

Coping with uncertain dynamics in visual tracking : redundant state models and discrete search methods  

E-Print Network (OSTI)

A model of the world dynamics is a vital part of any tracking algorithm. The observed world can exhibit multiple complex dynamics at different spatio-temporal scales. Faithfully modeling all motion constraints in a ...

Taycher, Leonid

2006-01-01T23:59:59.000Z

360

Nuclear Hybrid Energy System Modeling: RELAP5 Dynamic Coupling Capabilities  

SciTech Connect

The nuclear hybrid energy systems (NHES) research team is currently developing a dynamic simulation of an integrated hybrid energy system. A detailed simulation of proposed NHES architectures will allow initial computational demonstration of a tightly coupled NHES to identify key reactor subsystem requirements, identify candidate reactor technologies for a hybrid system, and identify key challenges to operation of the coupled system. This work will provide a baseline for later coupling of design-specific reactor models through industry collaboration. The modeling capability addressed in this report focuses on the reactor subsystem simulation.

Piyush Sabharwall; Nolan Anderson; Haihua Zhao; Shannon Bragg-Sitton; George Mesina

2012-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamic optimization model" 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

Scale-Free model for governing universe dynamics  

E-Print Network (OSTI)

We investigate the effects of scale-free model on cosmology, providing, in this way, a statistical background in the framework of general relativity. In order to discuss properties and time evolution of some relevant universe dynamical parameters (cosmographic parameters), such as $H(t)$ (Hubble parameter), $q(t)$ (deceleration parameter), $j(t)$ (jerk parameter) and $s(t)$ (snap parameter), which are well re-defined in the framework of scale-free model, we analyze a comparison between WMAP data. Hence the basic purpose of the work is to consider this statistical interpretation of mass distribution of universe, in order to have a mass density $\\rho$ dynamics, not inferred from Friedmann equations, via scale factor $a(t)$. This model, indeed, has been used also to explain a possible origin and a viable explanation of cosmological constant, which assumes a statistical interpretation without the presence of extended theories of gravity; hence the problem of dark energy could be revisited in the context of a classical probability distribution of mass, which is, in particular, for the scale-free model, $P(k)\\sim k^{-\\gamma}$, with $2<\\gamma<3$. The $\\Lambda$CDM model becomes, with these considerations, a consequence of the particular statistics together with the use of general relativity.

Orlando Luongo; Carmine Autieri

2009-02-21T23:59:59.000Z

362

Modeling space plasma dynamics with anisotropic Kappa distributions  

E-Print Network (OSTI)

Space plasmas are collisionpoor and kinetic effects prevail leading to wave fluctuations, which transfer the energy to small scales: wave-particle interactions replace collisions and enhance dispersive effects heating particles and producing suprathermal populations observed at any heliospheric distance in the solar wind. At large distances collisions are not efficient, and the selfgenerated instabilities constrain the solar wind anisotropy including the thermal core and the suprathermal components. The generalized power-laws of Kappa-type are the best fitting model for the observed distributions of particles, and a convenient mathematical tool for modeling their dynamics. But the anisotropic Kappa models are not correlated with the observations leading, in general, to inconsistent effects. This review work aims to reconcile some of the existing Kappa models with the observations.

Lazar, M; Poedts, S; Schlickeiser, R

2012-01-01T23:59:59.000Z

363

A DYNAMIC CRASHING METHOD FOR PROJECT MANAGEMENT USING SIMULATION-BASED OPTIMIZATION  

E-Print Network (OSTI)

the av- erage project cost due to lateness penalties and crashing costs. This dynamic approach will let of the project completion time, a distribution of the project total cost, and the project cost savings. 1 additional costs, crashing decisions need to be made in a cost-effective way. When crashing a project

Kuhl, Michael E.

364

Solving the job-shop scheduling problem optimally by dynamic programming  

Science Conference Proceedings (OSTI)

Scheduling problems received substantial attention during the last decennia. The job-shop problem is a very important scheduling problem, which is NP-hard in the strong sense and with well-known benchmark instances of relatively small size which attest ... Keywords: Complexity analysis, Dynamic programming, Job-shop scheduling

Joaquim A. S. Gromicho; Jelke J. Van Hoorn; Francisco Saldanha-Da-Gama; Gerrit T. Timmer

2012-12-01T23:59:59.000Z

365

Near-optimal, dynamic module reconfiguration in a photovoltaic system to combat partial shading effects  

Science Conference Proceedings (OSTI)

Partial shading is a serious obstacle to effective utilization of photovoltaic (PV) systems since it can result in significant output power degradation for the system. A PV system is organized as a series connection of PV modules, each module comprising ... Keywords: dynamic programming, partial shading, photovoltaic module reconfiguration, photovoltaic system

Xue Lin; Yanzhi Wang; Siyu Yue; Donghwa Shin; Naehyuck Chang; Massoud Pedram

2012-06-01T23:59:59.000Z

366

Modeling NOx emissions from coal-fired utility boilers using support vector regression with ant colony optimization  

Science Conference Proceedings (OSTI)

Modeling NO"x emissions from coal fired utility boiler is critical to develop a predictive emissions monitoring system (PEMS) and to implement combustion optimization software package for low NO"x combustion. This paper presents an efficient NO"x emissions ... Keywords: Ant colony optimization, Artificial neural networks, Combustion modeling, NOx emissions modeling, Support vector regression

Hao Zhou; Jia Pei Zhao; Li Gang Zheng; Chun Lin Wang; Ke Fa Cen

2012-02-01T23:59:59.000Z

367

Multidisciplinary Modeling, Control, and Optimization of a Solid Oxide Fuel Cell/Gas Turbine Hybrid Power System.  

E-Print Network (OSTI)

??This thesis describes a systematical study, including multidisciplinary modeling, simulation, control, and optimization, of a fuel cell - gas turbine hybrid power system that aims… (more)

Abbassi Baharanchi, Atid

2009-01-01T23:59:59.000Z

368

Computational fluid dynamic modeling of fluidized-bed polymerization reactors  

SciTech Connect

Polyethylene is one of the most widely used plastics, and over 60 million tons are produced worldwide every year. Polyethylene is obtained by the catalytic polymerization of ethylene in gas and liquid phase reactors. The gas phase processes are more advantageous, and use fluidized-bed reactors for production of polyethylene. Since they operate so close to the melting point of the polymer, agglomeration is an operational concern in all slurry and gas polymerization processes. Electrostatics and hot spot formation are the main factors that contribute to agglomeration in gas-phase processes. Electrostatic charges in gas phase polymerization fluidized bed reactors are known to influence the bed hydrodynamics, particle elutriation, bubble size, bubble shape etc. Accumulation of electrostatic charges in the fluidized-bed can lead to operational issues. In this work a first-principles electrostatic model is developed and coupled with a multi-fluid computational fluid dynamic (CFD) model to understand the effect of electrostatics on the dynamics of a fluidized-bed. The multi-fluid CFD model for gas-particle flow is based on the kinetic theory of granular flows closures. The electrostatic model is developed based on a fixed, size-dependent charge for each type of particle (catalyst, polymer, polymer fines) phase. The combined CFD model is first verified using simple test cases, validated with experiments and applied to a pilot-scale polymerization fluidized-bed reactor. The CFD model reproduced qualitative trends in particle segregation and entrainment due to electrostatic charges observed in experiments. For the scale up of fluidized bed reactor, filtered models are developed and implemented on pilot scale reactor.

Rokkam, Ram [Ames Laboratory

2012-11-02T23:59:59.000Z

369

Computational Fluid Dynamics Modeling of Atmospheric Flow Applied to Wind Energy Research.  

E-Print Network (OSTI)

??High resolution atmospheric flow modeling using computational fluid dynamics (CFD) has many applications in the wind energy industry. A well designed model can accurately calculate… (more)

Russell, Alan

2009-01-01T23:59:59.000Z

370

Reliability-yield allocation for semiconductor integrated circuits: modeling and optimization  

E-Print Network (OSTI)

This research develops yield and reliability models for fault-tolerant semiconductor integrated circuits and develops optimization algorithms that can be directly applied to these models. Since defects cause failures in microelectronics systems, accurate yield and reliability models considering these defects as well as optimization techniques determining efficient defect-tolerant schemes are essential in semiconductor manufacturing and nanomanufacturing to ensure manufacturability and productivity. The defect-based yield model considers various types of failures, fault-tolerant schemes such as hierarchical redundancy and error correcting code, and burn-in effects, simultaneously. The reliability model counts on carry-over single-cell failures accompanied by the failure rate of the semiconductor integrated circuits under the assumption of an error correcting code policy. The redundancy allocation problem, which seeks to ?nd an optimal allocation of redundancy that maximizes system reliability, is one of the representative problems in reliability optimization. The problem is typically formulated as a nonconvex integer nonlinear programming problem that is nonseparable and coherent. Two iterative heuristics, tree and scanning heuristics, and variants are studied to obtain local optima and a branch-and-bound algorithm is proposed to ?nd the global optimum for redundancy allocation problems. The proposed algorithms engage a multiple-search paths strategy to accelerate efficiency. Experimental results of these algorithms indicate that they are superior to the existing algorithms in terms of computation time and solution quality. An example of memory semiconductor integrated circuits is presented to show the applicability of both the yield and reliability models and the optimization algorithms to fault-tolerant semiconductor integrated circuits.

Ha, Chunghun

2004-08-01T23:59:59.000Z

371

Phase-only shaped laser pulses in optimal control theory: Application to indirect photofragmentation dynamics in the weak-field limit  

SciTech Connect

We implement phase-only shaped laser pulses within quantum optimal control theory for laser-molecule interaction. This approach is applied to the indirect photofragmentation dynamics of NaI in the weak-field limit. It is shown that optimized phase-modulated pulses with a fixed frequency distribution can substantially modify transient dissociation probabilities as well as the momentum distribution associated with the relative motion of Na and I.

Shu, Chuan-Cun; Henriksen, Niels E. [Department of Chemistry, Building 207, Technical University of Denmark, DK-2800, Kongens Lyngby (Denmark)

2012-01-28T23:59:59.000Z

372

An extremal optimization search method for the protein folding problem: the go-model example  

Science Conference Proceedings (OSTI)

The protein folding problem consists of predicting the functional (native)structure of the protein given its linear sequence of amino acids. Despite extensive progress made in understanding the process of protein folding, this problem still remains ... Keywords: extremal optimization, go-model, protein folding

Alena Shmygelska

2007-07-01T23:59:59.000Z

373

Modelling and Design Optimization of Low Speed Fuel Cell Hybrid Electric Vehicles  

E-Print Network (OSTI)

of emissions to global climate change. Although electric cars and buses have been the focus of much of electricModelling and Design Optimization of Low Speed Fuel Cell Hybrid Electric Vehicles by Matthew Blair Supervisors: Dr. Zuomin Dong ABSTRACT Electric vehicles, as an emerging transportation platform, have been

Victoria, University of

374

Modeling of Optimal Oil Production and Comparing with Actual and Contractual Oil Production: Iran Case  

E-Print Network (OSTI)

Modeling of Optimal Oil Production and Comparing with Actual and Contractual Oil Production: Iran, Davis Introduction · The Iran Oil Project, initiated in 2007, aims to find the inefficiencies and their possible sources in Iranian oil and gas policies. Background Information Assumptions · Perfect Competition

California at Davis, University of

375

Optimization of scale and parametrization for terrain segmentation: An application to soil-landscape modeling  

Science Conference Proceedings (OSTI)

This paper presents a procedure to optimize parametrization and scale for terrain-based environmental modeling. The workflow was exemplified on crop yield data, which is assumed to represent a proxy for soil productivity. Focal mean statistics were used ... Keywords: Curvature, Focal mean statistics, OBIA, Regression, Soil productivity., Terrain segmentation

Lucian Drgu; Thomas Schauppenlehner; Andreas Muhar; Josef Strobl; Thomas Blaschke

2009-09-01T23:59:59.000Z

376

Modeling and optimizing maintenance schedule for energy systems subject to degradation  

Science Conference Proceedings (OSTI)

In recent years, with the increasing investment on distributed energy system (DES), maintenance management has played an important role in improving the system performance. This paper aims to integrate the conception of the multiple attribute value theory ... Keywords: Distributed energy system, Imperfect maintenance, Multi-attribute model, Optimal schedule, Sequential preventive maintenance

Tangbin Xia; Lifeng Xi; Xiaojun Zhou; Shichang Du

2012-11-01T23:59:59.000Z

377

Nonlinear controller optimization of a power system based on reduced multivariate polynomial model  

Science Conference Proceedings (OSTI)

This paper describes the design of a nonlinear controller in a power system by using the reduced multivariate polynomial (RMP) optimization algorithm with the one-shot training property. The RMP model is applied to estimate its Hessian matrix in addition ...

Seung-Mook Baek; Jung-Wook Park

2009-06-01T23:59:59.000Z

378

Dynamic simulation model for non-supplementary firing triple-pressure heat recovery steam generator  

Science Conference Proceedings (OSTI)

By using the modular modeling method, a real-time dynamic simulation model for the non-supplementary tri-pressure reheat Heat Recovery Steam Generator (HRSG) is developed. On the basis of mass and energy conservation law, the paper discusses the model ... Keywords: HRSG, dynamic model, modular modelling, simulation

Ning Cui; Bing-Shu Wang; Xiang-Yang Gong; Jian-Qiang Gao

2007-10-01T23:59:59.000Z

379

Model for Aggregated Water Heater Load Using Dynamic Bayesian Networks  

Science Conference Proceedings (OSTI)

The transition to the new generation power grid, or “smart grid”, requires novel ways of using and analyzing data collected from the grid infrastructure. Fundamental functionalities like demand response (DR), that the smart grid needs, rely heavily on the ability of the energy providers and distributors to forecast the load behavior of appliances under different DR strategies. This paper presents a new model of aggregated water heater load, based on dynamic Bayesian networks (DBNs). The model has been validated against simulated data from an open source distribution simulation software (GridLAB-D). The results presented in this paper demonstrate that the DBN model accurately tracks the load profile curves of aggregated water heaters under different testing scenarios.

Vlachopoulou, Maria; Chin, George; Fuller, Jason C.; Lu, Shuai; Kalsi, Karanjit

2012-07-19T23:59:59.000Z

380

The Third State of the Schelling Model of Residential Dynamics  

E-Print Network (OSTI)

The Schelling model of segregation between two groups of residential agents (Schelling 1971; Schelling 1978) reflects the most abstract view of the non-economic forces of residential migrations: be close to people of 'your own'. The model assumes that the residential agent, located in the neighborhood where the fraction of 'friends' is less than a predefined threshold value F, tries to relocate to a neighborhood for which this fraction is above F. It is well known that for the equal groups, depending on F, Schelling's residential pattern converges either to complete integration (random pattern) or segregation. We investigate Schelling model pattern dynamics as dependent on F, the ratio of the group numbers and the size of the neighborhood and demonstrate that the traditional integrate-segregate dichotomy is incomplete. In case of unequal groups, there exists the wide interval of the F-values that entails the third persistent residential pattern, in which part of the majority population segregates, while the r...

Benenson, Itzhak

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamic optimization model" 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

Interactive computational models of particle dynamics using virtual reality  

DOE Green Energy (OSTI)

An increasing number of industrial applications rely on computational models to reduce costs in product design, development, and testing cycles. Here, the authors discuss an interactive environment for the visualization, analysis, and modification of computational models used in industrial settings. In particular, they focus on interactively placing massless, massed, and evaporating particulate matter in computational fluid dynamics applications.they discuss the numerical model used to compute the particle pathlines in the fluid flow for display and analysis. They briefly describe the toolkits developed for vector and scalar field visualization, interactive particulate source placement, and a three-dimensional GUI interface. This system is currently used in two industrial applications, and they present the tools in the context of these applications. They summarize the current state of the project and offer directions for future research.

Canfield, T.; Diachin, D.; Freitag, L.; Heath, D.; Herzog, J. [Argonne National Lab., IL (United States); Michels, W. [Nalco Fuel Tech, Naperville, IL (United States)

1996-12-31T23:59:59.000Z

382

Models, Calculation and Optimization of Gas Networks, Equipment and Contracts for Design, Operation, Booking and Accounting  

E-Print Network (OSTI)

There are proposed models of contracts, technological equipment and gas networks and methods of their optimization. The flow in network undergoes restrictions of contracts and equipment to be operated. The values of sources and sinks are provided by contracts. The contract models represent (sub-) networks. The simplest contracts represent either nodes or edges. Equipment is modeled by edges. More sophisticated equipment is represented by sub-networks. Examples of such equipment are multi-poles and compressor stations with many entries and exits. The edges can be of different types corresponding to equipment and contracts. On such edges, there are given systems of equation and inequalities simulating the contracts and equipment. On this base, the methods proposed that allow: calculation and control of contract values for booking on future days and for accounting of sales and purchases; simulation and optimization of design and of operation of gas networks. These models and methods are realized in software syst...

Ostromuhov, Leonid A

2011-01-01T23:59:59.000Z

383

Optimization of a petroleum producing assets portfolio: development of an advanced computer model  

E-Print Network (OSTI)

Portfolios of contemporary integrated petroleum companies consist of a few dozen Exploration and Production (E&P) projects that are usually spread all over the world. Therefore, it is important not only to manage individual projects by themselves, but to also take into account different interactions between projects in order to manage whole portfolios. This study is the step-by-step representation of the method of optimizing portfolios of risky petroleum E&P projects, an illustrated method based on Markowitz’s Portfolio Theory. This method uses the covariance matrix between projects’ expected return in order to optimize their portfolio. The developed computer model consists of four major modules. The first module generates petroleum price forecasts. In our implementation we used the price forecasting method based on Sequential Gaussian Simulation. The second module, Monte Carlo, simulates distribution of reserves and a set of expected production profiles. The third module calculates expected after tax net cash flows and estimates performance indicators for each realization, thus yielding distribution of return for each project. The fourth module estimates covariance between return distributions of individual projects and compiles them into portfolios. Using results of the fourth module, analysts can make their portfolio selection decisions. Thus, an advanced computer model for optimization of the portfolio of petroleum assets has been developed. The model is implemented in a MATLAB® computational environment and allows optimization of the portfolio using three different return measures (NPV, GRR, PI). The model has been successfully applied to the set of synthesized projects yielding reasonable solutions in all three return planes. Analysis of obtained solutions has shown that the given computer model is robust and flexible in terms of input data and output results. Its modular architecture allows further inclusion of complementary “blocks” that may solve optimization problems utilizing different measures (than considered) of risk and return as well as different input data formats.

Aibassov, Gizatulla

2007-12-01T23:59:59.000Z

384

A model for the ATW target region fluid dynamics  

SciTech Connect

In the Los Alamos National Laboratory's concept for the accelerator transmutation of waste (ATW), a lead-bismuth eutectic has been chosen as a spallation target for the proton beam. Because of the high local heat fluxes anticipated, the target is in liquid form to facilitate heat removal. The upper boundary of the target region is a hard vacuum. The primary purpose of the analysis is to determine the location of the flow boundary based on the target design parameters. This method of analysis should prove to be useful for performing preliminary scoping and design of the ATW target region's fluid dynamics. Eventually, this model should be tested against experimental data.

Rider, W.J.; Cappiello, M.W. (Los Alamos National Lab., NM (United States))

1991-01-01T23:59:59.000Z

385

Optimizing fracture stimulation using treatment-well tiltmeters and integrated fracture modeling  

Science Conference Proceedings (OSTI)

This paper covers the optimization of hydraulic fracture treatments in a new coalbed methane (CBM) reservoir in Wyoming. A multiwell pilot project was conducted in the Copper Ridge (CR) field to assess future development potential. Hydraulic fracture mapping was successfully performed with treatment-well tiltmeters on six wells including the first-ever used on propped treatments. The mapped fracture height was then used to calibrate the fracture model, perform on-site fracture-design changes, and optimize future fracture treatments. This paper shows how early use of fracture diagnostics can assist in the development of a new reservoir.

Mayerhofer, M.; Stutz, L.; Davis, E.; Wolhart, S. [Pinnacle Technology Houston, Houston, TX (United States)

2006-05-15T23:59:59.000Z

386

Dynamic Pricing: A learning Approach  

E-Print Network (OSTI)

We present an optimization approach for jointly learning the demand as a functionof price, and dynamically setting prices of products in an oligopoly environment in order to maximize expected revenue. The models we consider ...

Bertsimas, Dimitris J.

387

Dynamic Properties of Molecular Motors in Burnt-Bridge Models  

E-Print Network (OSTI)

Dynamic properties of molecular motors that fuel their motion by actively interacting with underlying molecular tracks are studied theoretically via discrete-state stochastic ``burnt-bridge'' models. The transport of the particles is viewed as an effective diffusion along one-dimensional lattices with periodically distributed weak links. When an unbiased random walker passes the weak link it can be destroyed (``burned'') with probability p, providing a bias in the motion of the molecular motor. A new theoretical approach that allows one to calculate exactly all dynamic properties of motor proteins, such as velocity and dispersion, at general conditions is presented. It is found that dispersion is a decreasing function of the concentration of bridges, while the dependence of dispersion on the burning probability is more complex. Our calculations also show a gap in dispersion for very low concentrations of weak links which indicates a dynamic phase transition between unbiased and biased diffusion regimes. Theoretical findings are supported by Monte Carlo computer simulations.

Maxim N. Artyomov; Alexander Yu. Morozov; Ekaterina Pronina; Anatoly B. Kolomeisky

2007-05-04T23:59:59.000Z

388

FODO-Supercell Based Compact Ring Design with Tunable Momentum Compaction and Optimized Dynamic Aperture  

Science Conference Proceedings (OSTI)

A storage ring with tunable momentum compaction has the advantage in achieving different RMS bunch length with similar RF capacity, which is potentially useful for many applications, such as linear collider damping ring and predamping ring where injected beam has a large energy spread and a large transverse emittance. A tunable bunch length also makes the commissioning and fine tuning easier in manipulating the single bunch instabilities. In this paper, a compact ring design based on a supercell is presented, which achieves a tunable momentum compaction while maintaining a large dynamic aperture.

Sun, Yipeng; /SLAC

2012-05-03T23:59:59.000Z

389

FODO-Supercell Based Compact Ring Design with Tunable Momentum Compaction and Optimized Dynamic Aperture  

Science Conference Proceedings (OSTI)

A storage ring with tunable momentum compaction has the advantage in achieving different RMS bunch length with similar RF capacity, which is potentially useful for many applications, such as linear collider damping ring and pre-damping ring where injected beam has a large energy spread and a large transverse emittance. A tunable bunch length also makes the commissioning and fine tuning easier in manipulating the single bunch instabilities. In this paper, a compact ring design based on a supercell is presented, which achieves a tunable momentum compaction while maintaining a large dynamic aperture.

Sun, Yipeng; /SLAC

2012-05-11T23:59:59.000Z

390

Optimal control of remote hybrid power systems. Part 1: Simplified model  

SciTech Connect

In this two-part study, time-series models are used to determine optimal dispatch strategies, in conjunction with optimally-sized components, in remote hybrid power systems. The objective of the dispatch optimization is to minimize the costs associated with diesel fuel, diesel starts, and battery erosion, based on a thorough economic analysis of present worth life-cycle cost. An ideal predictive control strategy is used as a basis of comparison. In Part 1 (reported here), a simplified time-series model is used to obtain preliminary conceptual results. These results illustrate the nature of the optimal dispatch strategy and indicate that a simple SOC setpoint strategy can be practically as effective as the ideal predictive control. In Part 2 (at a later date), a more detailed model will be used to obtain more accurate, quantitative results. The authors anticipate that these results will be correlated to dimensionless economic, design, and performance parameters, rendering them useful as design guidelines over a wide variety of load profiles, climates, equipment specifications, and economic variables.

Barley, C D [Colorado State Univ., Fort Collins, CO (United States). Mechanical Engineering Dept.; [National Renewable Energy Lab., Golden, CO (United States). Wind Technology Div.; Winn, C B [Colorado State Univ., Fort Collins, CO (United States); Flowers, L; Green, H J [National Renewable Energy Lab., Golden, CO (United States). Wind Technology Div.

1995-04-01T23:59:59.000Z

391

Aggregate Models based on Improved Group Methods for Simulation and Optimization of Distillation Systems  

E-Print Network (OSTI)

This note deals with aggregate models for complex distillation systems in largescale flowsheets. Group methods were originally devised for simple absorber and stripper calculations with no major extensions for handling distillation. In this work, group methods are systematically analyzed and further improved by modifying some of the previously proposed approximations. As a result, the improved group method exhibits accurate predictions and this is demonstrated using simulation and optimization case studies for a variety of chemical systems and operating conditions. It is observed that the prediction of output variables is in close agreement with that of the rigorous equilibrium stage model. In case of optimization problems, the optimal number of trays and feed locations differ by only one or two trays. The aggregate model can be applied in a sequence of steps in order to improve the reliability and robustness of the solution procedure. A rounding heuristic is also proposed which can provide near-optimal solutions with a significant reduction in computational time. ?To whom correspondence should be addressed.

Ravindra S. Kamath; Ignacio E. Grossmann; Lorenz T. Biegler

2009-01-01T23:59:59.000Z

392

Optimization of density functional tight-binding and classical reactive molecular dynamics for high-throughput simulations of carbon materials  

Science Conference Proceedings (OSTI)

Carbon materials and nanostructures (fullerenes, nanotubes) are promising building blocks of nanotechnology. Potential applications include optical and electronic devices, sensors, and nano-scale machines. The multiscale character of processes related ... Keywords: ACM proceedings, BLAS, Cray XT5, LAPACK, advanced materials, density-functional tight binding, high-throughput, linear algebra, material science, molecular dynamics, multiscale-modeling, quantum chemistry, scientific libraries, scientific-computing

Jacek Jakowski; Bilel Hadri; Steven J. Stuart; Predrag Krstic; Stephan Irle; Dulma Nugawela; Sophya Garashchuk

2012-07-01T23:59:59.000Z

393

Model Predictive Control-based Optimal Coordination of Distributed Energy Resources  

SciTech Connect

Distributed energy resources, such as renewable energy resources (wind, solar), energy storage and demand response, can be used to complement conventional generators. The uncertainty and variability due to high penetration of wind makes reliable system operations and controls challenging, especially in isolated systems. In this paper, an optimal control strategy is proposed to coordinate energy storage and diesel generators to maximize wind penetration while maintaining system economics and normal operation performance. The goals of the optimization problem are to minimize fuel costs and maximize the utilization of wind while considering equipment life of generators and energy storage. Model predictive control (MPC) is used to solve a look-ahead dispatch optimization problem and the performance is compared to an open loop look-ahead dispatch problem. Simulation studies are performed to demonstrate the efficacy of the closed loop MPC in compensating for uncertainties and variability caused in the system.

Mayhorn, Ebony T.; Kalsi, Karanjit; Lian, Jianming; Elizondo, Marcelo A.

2013-01-07T23:59:59.000Z

394

Improving Health Care Management Through the Use of Dynamic Simulation Modeling and Health Information Systems  

Science Conference Proceedings (OSTI)

To better understand the performance of hospital operations in response to IT-enabled improvement, this paper reports the results of a system dynamics model designed to improve core medical processes. Utilizing system dynamics modeling and emerging Health ... Keywords: Health Information Systems, Heath Care, Hospital Management, Process Improvement, System Dynamics

Daniel Goldsmith; Michael Siegel

2012-01-01T23:59:59.000Z

395

Time Series Forecasting for Dynamic Environments: the DyFor Genetic Program Model  

E-Print Network (OSTI)

Time Series Forecasting for Dynamic Environments: the DyFor Genetic Program Model Neal Wagner programming (GP) to the task of forecasting with favorable results. However, these studies, like those "dynamic" GP model that is specifically tailored for forecasting in non-static environments. This Dynamic

Michalewicz, Zbigniew

396

Hybrid Powertrain Optimization for Plug-In Microgrid Power Generation Automated Modeling Laboratory Slide 1 of 28  

E-Print Network (OSTI)

Hybrid Powertrain Optimization for Plug-In Microgrid Power Generation Automated Modeling LaboratoryPlug--InIn MicrogridMicrogrid Power GenerationPower Generation Scott J. MouraScott J. Moura DongsukDongsuk KumKum Hosam Powertrain Optimization for Plug-In Microgrid Power Generation Automated Modeling Laboratory Slide 2 of 28

Krstic, Miroslav

397

Reflections on Monetary Policy Choices in the Open Economy: Implications from an Optimizing Model  

E-Print Network (OSTI)

The purpose of this paper is to provide some intuition and insight into monetary policy choices faced in the open economy. The approach we pursue is to ‘inspect the mechanism ’ of the two country Clarida, Gali, Gertler (2002) optimizing model by focusing on the three main building blocks that can be derived from it: the ‘open economy ’ IS curve, the open economy Phillips curve, and the open economy Taylor rule. We emphasize the following results that are based open a benchmark specification of the model which assume that the elasticity of intertemporal substitution in consumption is less than 1. First, there will in general be a spillover from foreign output to potential domestic output. Second, there will in general be a spillover from foreign output growth to the domestic neutral real interest rate. Third, we show that a more open economy has a flatter IS curve. Fourth, we show that a more open economy has a flatter Phillips curve. We discuss that a more open economy places a larger weight on inflation stabilization in the appropriately derived quadratic approximation to the social welfare function. Sixth, we review that optimal monetary policy in the open economy can be written as a Taylor rule in the neutral real interest rate and expected domestic inflation. Seventh, we show that in a more open economy the optimal Taylor rule coefficient on expected inflation is smaller than in a more closed economy, so that the central bank needs to lean less against the wind for any given inflation shock. Eighth, while a Taylor rule is one way to write the optimal policy rule, the optimal policy rule can also be written as an augmented Taylor rule that includes the rate of nominal exchange rate depreciation and the home ? foreign growth differential. Ninth, there is a presumption that, under optimal monetary policy, bad news about inflation will be good news for the exchange rate. Reflections on Monetary Policy Choices in the Open Economy:

Richard H. Clarida; Richard H. Clarida

2007-01-01T23:59:59.000Z

398

Dynamic Model of Hydrogen in GaN  

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

Dynamic Model of Hydrogen in GaN by S. M. Myers and A. F. Wright Motivation-Hydrogen is incorporated into p-type GaN during MOCVD growth, producing highly stable passivation of the Mg acceptors. Complete acceptor activation by thermal H release requires temperatures that threaten material integrity, prompting compromises in device processing. At lower temperatures, forward bias of p-n junctions or electron-beam irradiation produces a metastable, reversible activation without H release. To understand and control such effects, we are developing a mathematical model of H behavior wherein state energies from density-functional theory are employed in diffusion-reaction equations. Previously, we used the greatly simplifying assumptions of local equilibrium among states

399

Dynamic chirality in the interacting boson fermion-fermion model  

SciTech Connect

The chiral interpretation of twin bands in odd-odd nuclei was investigated in the interacting boson fermion-fermion model. The analysis of the wave functions has shown that the possibility for angular momenta of the valence proton, neutron and core to find themselves in the favorable, almost orthogonal geometry is present, but not dominant. Such behavior is found to be similar in nuclei where both the level energies and the electromagnetic decay properties display the chiral pattern, as well as in those where only the level energies of the corresponding levels in the twin bands are close together. The difference in the structure of the two types of chiral candidates nuclei can be attributed to different {beta} and {gamma} fluctuations, induced by the exchange boson-fermion interaction of the interacting boson fermion-fermion model. In both cases the chirality is weak and dynamic.

Brant, S. [Department of Physics, Faculty of Science, University of Zagreb, 10000 Zagreb (Croatia); Tonev, D. [INFN, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Italy); Institute for Nuclear Research and Nuclear Energy, BAS, 1784 Sofia (Bulgaria); De Angelis, G. [INFN, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Italy); Ventura, A. [Ente per le Nuove tecnologie, l'Energia e l'Ambiente, I-40129 Bologna and Istituto Nazionale di Fisica Nucleare, Sezione di Bologna (Italy)

2008-09-15T23:59:59.000Z

400

Evaluating Aspects of the Community Land and Atmosphere Models (CLM3 and CAM3) Using a Dynamic Global Vegetation Model  

Science Conference Proceedings (OSTI)

The Community Land Model version 3 (CLM3) Dynamic Global Vegetation Model (CLM–DGVM) is used diagnostically to identify land and atmospheric model biases that lead to biases in the simulated vegetation. The CLM–DGVM driven with observed ...

Gordon B. Bonan; Samuel Levis

2006-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamic optimization model" 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

Choose inter-element coupling to preserve self-adjoint dynamics in multiscale modelling and computation  

Science Conference Proceedings (OSTI)

Consider the macroscale modelling of microscale spatio-temporal dynamics. Here we develop an approach to ensure coarse scale discrete models preserve important self-adjoint properties of the microscale dynamics. The first part explores the discrete modelling ... Keywords: Centre manifold theory, Closure, Macroscale discretisation, Multiscale modelling

A. J. Roberts

2010-10-01T23:59:59.000Z

402

CAM-SE: A scalable spectral element dynamical core for the Community Atmosphere Model  

Science Conference Proceedings (OSTI)

The Community Atmosphere Model (CAM) version 5 includes a spectral element dynamical core option from NCAR's High-Order Method Modeling Environment. It is a continuous Galerkin spectral finite-element method designed for fully unstructured quadrilateral ... Keywords: atmospheric modeling, dynamical core, global circulation model, parallel scalability, spectral elements

John M. Dennis; Jim Edwards; Katherine J. Evans; Oksana Guba; Peter H. Lauritzen; Arthur A. Mirin; Amik St-Cyr; Mark A. Taylor; Patrick H. Worley

2012-02-01T23:59:59.000Z

403

Position Paper: A general framework for Dynamic Emulation Modelling in environmental problems  

Science Conference Proceedings (OSTI)

Emulation modelling is an effective way of overcoming the large computational burden associated with the process-based models traditionally adopted by the environmental modelling community. An emulator is a low-order, computationally efficient model ... Keywords: Dynamic emulation modelling, Metamodelling, Model complexity, Model reduction, Process-based models, Response surfaces

A. Castelletti; S. Galelli; M. Ratto; R. Soncini-Sessa; P. C. Young

2012-06-01T23:59:59.000Z

404

A comparative study of Lotka-Volterra and system dynamics models for simulation of technology industry dynamics  

E-Print Network (OSTI)

Scholars have developed a range of qualitative and quantitative models for generalizing the dynamics of technological innovation and identifying patterns of competition between rivals. This thesis compares two predominant ...

Ünver, Hakk? Özgür

2008-01-01T23:59:59.000Z

405

Modeling Temporal Behavior in Large Networks: A Dynamic Mixed-Membership Model  

SciTech Connect

Given a large time-evolving network, how can we model and characterize the temporal behaviors of individual nodes (and network states)? How can we model the behavioral transition patterns of nodes? We propose a temporal behavior model that captures the 'roles' of nodes in the graph and how they evolve over time. The proposed dynamic behavioral mixed-membership model (DBMM) is scalable, fully automatic (no user-defined parameters), non-parametric/data-driven (no specific functional form or parameterization), interpretable (identifies explainable patterns), and flexible (applicable to dynamic and streaming networks). Moreover, the interpretable behavioral roles are generalizable, computationally efficient, and natively supports attributes. We applied our model for (a) identifying patterns and trends of nodes and network states based on the temporal behavior, (b) predicting future structural changes, and (c) detecting unusual temporal behavior transitions. We use eight large real-world datasets from different time-evolving settings (dynamic and streaming). In particular, we model the evolving mixed-memberships and the corresponding behavioral transitions of Twitter, Facebook, IP-Traces, Email (University), Internet AS, Enron, Reality, and IMDB. The experiments demonstrate the scalability, flexibility, and effectiveness of our model for identifying interesting patterns, detecting unusual structural transitions, and predicting the future structural changes of the network and individual nodes.

Rossi, R; Gallagher, B; Neville, J; Henderson, K

2011-11-11T23:59:59.000Z

406

Data Assimilation with Gaussian Mixture Models Using the Dynamically Orthogonal Field Equations. Part II: Applications  

Science Conference Proceedings (OSTI)

The properties and capabilities of the Gaussian Mixture Model–Dynamically Orthogonal filter (GMM-DO) are assessed and exemplified by applications to two dynamical systems: 1) the double well diffusion and 2) sudden expansion flows; both of which ...

Thomas Sondergaard; Pierre F. J. Lermusiaux

2013-06-01T23:59:59.000Z

407

Dynamic Cost-Loss Ratio Decision-making Model with an Autocorrelated Climate Variable  

Science Conference Proceedings (OSTI)

A dynamic decision-making problem is considered involving the use of information about the autocorrelation of a climate variable. Specifically, an infinite horizon, discounted version of the dynamic cost-loss ratio model is treated, in which only ...

Richard W. Katz

1993-01-01T23:59:59.000Z

408

Reduced-order, trajectory piecewise-linear models for nonlinear computational fluid dynamics  

E-Print Network (OSTI)

Computational fluid dynamics (CFD) is now widely used throughout the fluid dynamics community and yields accurate models for problems of interest. However, due to its high computational cost, CFD is limited for some ...

Gratton, David, 1979-

2004-01-01T23:59:59.000Z

409

A diffusion theory model for optimization calculations of cold neutron sources  

DOE Green Energy (OSTI)

This summary describes a simple two-group diffusion model of an infinite slab, liquid deuterium (LD/sub 2/) cold source. The simplicity of the model permits us to obtain an analytical solution from which we can deduce the reason for the optimum thickness based solely on diffusion type phenomena. Also, a second more sophisticated model is described, and the results compared to a deterministic transport calculation. The good (particularly qualitative) agreement between the results suggests that diffusion theory methods can be used in parametric and optimization studies in order to avoid the generally more expensive transport calculations. 5 refs., 1 fig.

Azmy, Y.Y.

1987-01-01T23:59:59.000Z

410

Overview of the principal Brookhaven energy system optimization models. [BESOM, three variants, and two applications  

Science Conference Proceedings (OSTI)

The Brookhaven Energy System Optimization Model (BESOM), three of its variants, and two examples of characteristic applications are described. BESOM is a linear-programming model that was developed for the quantitative evaluation of energy technologies and policies within a systems framework. The model is designed to examine interfuel substitutions in the context of constraints on the availability of competing resources and technologies. BESOM provides a snapshot of the national energy system configuration, while MARKAL and TESOM provide, respectively, a farsighted time dimension and a simulation capability for the examination of the evolution of a national energy system over a time horizon.

Kydes, A S

1980-11-01T23:59:59.000Z

411

Observations on the Optimality Tolerance in the CAISO 33% RPS Model  

DOE Green Energy (OSTI)

In 2008 Governor Schwarzenegger of California issued an executive order requiring that 33 percent of all electricity in the state in the year 2020 should come from renewable resources such as wind, solar, geothermal, biomass, and small hydroelectric facilities. This 33% renewable portfolio standard (RPS) was further codified and signed into law by Governor Brown in 2011. To assess the market impacts of such a requirement, the California Public Utilities Commission (CPUC) initiated a study to quantify the cost, risk, and timing of achieving a 33% RPS by 2020. The California Independent System Operator (CAISO) was contracted to manage this study. The production simulation model used in this study was developed using the PLEXOS software package, which allows energy planners to optimize long-term system planning decisions under a wide variety of system constraints. In this note we describe our observations on varying the optimality tolerance in the CAISO 33% RPS model. In particular, we observe that changing the optimality tolerance from .05% to .5% leads to solutions over 5 times faster, on average, producing very similar solutions with a negligible difference in overall distance from optimality.

Yao, Y; Meyers, C; Schmidt, A; Smith, S; Streitz, F

2011-09-22T23:59:59.000Z

412

Combining multi-objective optimization and bayesian model averaging to calibrate forecast ensembles of soil hydraulic models  

SciTech Connect

Most studies in vadose zone hydrology use a single conceptual model for predictive inference and analysis. Focusing on the outcome of a single model is prone to statistical bias and underestimation of uncertainty. In this study, we combine multi-objective optimization and Bayesian Model Averaging (BMA) to generate forecast ensembles of soil hydraulic models. To illustrate our method, we use observed tensiometric pressure head data at three different depths in a layered vadose zone of volcanic origin in New Zealand. A set of seven different soil hydraulic models is calibrated using a multi-objective formulation with three different objective functions that each measure the mismatch between observed and predicted soil water pressure head at one specific depth. The Pareto solution space corresponding to these three objectives is estimated with AMALGAM, and used to generate four different model ensembles. These ensembles are post-processed with BMA and used for predictive analysis and uncertainty estimation. Our most important conclusions for the vadose zone under consideration are: (1) the mean BMA forecast exhibits similar predictive capabilities as the best individual performing soil hydraulic model, (2) the size of the BMA uncertainty ranges increase with increasing depth and dryness in the soil profile, (3) the best performing ensemble corresponds to the compromise (or balanced) solution of the three-objective Pareto surface, and (4) the combined multi-objective optimization and BMA framework proposed in this paper is very useful to generate forecast ensembles of soil hydraulic models.

Vrugt, Jasper A [Los Alamos National Laboratory; Wohling, Thomas [NON LANL

2008-01-01T23:59:59.000Z

413

A Zonally Averaged Ocean Model for the Thermohaline Circulation. Part I: Model Development and Flow Dynamics  

Science Conference Proceedings (OSTI)

A two-dimensional latitude–depth ocean model is developed on the basis of the zonally averaged balance equations of mass, momentum, heat, and salt. Its purpose is to investigate the dynamics and variability of the buoyancy-forced thermohaline ...

Daniel G. Wright; Thomas F. Stocker

1991-12-01T23:59:59.000Z

414

Implications of a Regime-Switching Model on Natural Gas Storage Valuation and Optimal Operation  

E-Print Network (OSTI)

In this paper, we propose a one-factor regime-switching model for the risk adjusted natural gas spot price and study the implications of the model on the valuation and optimal operation of natural gas storage facilities. We calibrate the model parameters to both market futures and options on futures. Calibration results indicate that the regime-switching model is a better fit to market data compared to a one-factor mean-reverting model similar to those used by other authors to value gas storage. We extend a semi-Lagrangian timestepping scheme from Chen and Forsyth (2007) to solve the gas storage pricing problem, essentially a stochastic control problem, and conduct a convergence analysis of the scheme. Numerical results also indicate that the regime-switching model can generate operational strategies for gas storage facilities that reflect the existence of multiple regimes in the market as well as the regime shifts due to various exogenous events.

Zhuliang Chen; Peter A. Forsyth

2007-01-01T23:59:59.000Z

415

Dynamic modeling of plasma-vapor interactions during plasma disruptions  

SciTech Connect

Intense deposition of energy in short times on fusion reactor components during a plasma disruption may cause severe surface erosion due to ablation of these components. The exact amount of the eroded material is very important to the reactor design and its lifetime. During the plasma deposition, the vaporized wall material will interact with the incoming plasma particles and may shield the rest of the wall from damage. The vapor shielding may then prolong the lifetime of these components and increase the reactor duty cycle. To correctly evaluate the impact of vapor shielding effect a comprehensive model is developed. In this model the dynamic slowing down of the plasma particles, both ions and electrons, with the eroded wall material is established. Different interaction processes between the plasma particles and the ablated material is included. The generated photons radiation source and the transport of this radiation through the vapor to the wall is modeled. Recent experimental data on disruptions is analyzed and compared with model predictions. Vapor shielding may be effective in reducing the overall erosion rate for certain plasma disruption parameters and conditions.

Hassanein, A.; Ehst, D.A.

1992-05-01T23:59:59.000Z

416

Interlayer Structure and Dynamics of Cl-Bearing Hydrotalcite: Far Infrared Spectroscopy and Molecular Dynamics Modeling  

SciTech Connect

Comparison of the observed far-infrared (FIR) spectrum of Cl--containing hydrotalcite, [Mg3Al(OH)8]Cl?3H2O, with its power spectrum calculated using molecular dynamics (MD) computer simulation provides greatly increased understanding of the structure and vibrational dynamics in the interlayers of layered double hydroxides. The simulation model assumes an ordered Mg3Al arrangement in the octahedral layer and no constraints on the movement of any atoms or on the geometry and symmetry of the simulation supercell. Calculated anisotropic components of the individual atomic power spectra in combination with computed animations of the vibrational modes from normal mode analysis allow for reliable interpretations of the observed spectral bands. For the vibrations related to octahedral cation motions, bands near 145, 180 and 250 cm-1 are due dominantly to Mg vibration in the z direction (perpendicular to the hydroxide layers), Al vibration in the z direction and Mg and Al vibrations in the x-y plane (parallel to the hydroxide layers), respectively. The low frequency vibrational motions of the interlayer are controlled by a network of hydrogen bonds formed among interlayer water molecules, Cl- ions, and the OH groups of the main hydroxide layers. The bands near 40-70 cm-1 are related to the translational motions of interlayer Cl- and H2O in the x-y plane, and the bands near 120 cm-1 and 210 cm-1 are due largely to translational motions of the interlayer species in the z direction. The three librational modes of interlayer water molecules near 390, 450 and 540 cm-1 correspond to twisting, rocking and wagging hindered rotations, respectively. The spectral components of the interlayer Cl- motions are remarkably similar to those of bulk aqueous chloride solutions, reflecting the structural and dynamic similarity of the nearest-neighbor Cl- environments in the interlayer and in solution.

Wang, Jianwei; Kalinichev, Andrey G.; Amonette, James E.; Kirkpatrick, Robert J.

2003-02-01T23:59:59.000Z

417

Optimization Of Chromaticity Compensation And Dynamic Aperture In MEIC Collider Rings  

SciTech Connect

The conceptual design of the Medium-energy Electron-Ion Collider (MEIC) at Jefferson Lab relies on an ultra-small beta-star to achieve high luminosities of up to 10{sup 34} cm{sup -2} s{sup -1}. A low-beta insertion for interaction regions unavoidably induces large chromatic effects that demand a proper compensation. The present approach of chromatic compensation in the MEIC collider rings is based on a local correction scheme using two symmetric chromatic compensation blocks that includes families of sextupoles, and are placed in a beam extension area on both sides of a collision point. It can simultaneously compensate the first order chromaticity and chromatic beam smear at the IP without inducing significant second order aberrations. In this paper, we investigate both the momentum acceptance and dynamic aperture in the MEIC ion collider ring by considering the aberration effects up to the third order, such as amplitude dependent tune shift. We also explore the compensation of the third order effects by introducing families of octupoles in the extended beam area.

Fanglei Lin, Yaroslav Derbenev, Vasiliy Morozov, Yuhong Zhang, Kevin Beard

2012-07-01T23:59:59.000Z

418

A CELL-BASED MANY-TO-ONE DYNAMIC SYSTEM OPTIMAL MODELAND ITS  

E-Print Network (OSTI)

FOR EMERGENCY EVACUATION Henry X. Liu, Department of Civil Engineering, University of Minnesota, Twin Cities Xiaozheng He, Department of Civil Engineering, University of Minnesota, Twin Cities Jeff X. Ban, Institute, specific planning models have been developed for various evacuation scenarios, including nuclear plant

Ban, Xuegang "Jeff"

419

Risk Based Maintenance Optimization using Probabilistic Maintenance Quantification Models of Circuit Breaker  

E-Print Network (OSTI)

New maintenance techniques for circuit breakers are studied in this dissertation by proposing a probabilistic maintenance model and a new methodology to assess circuit breaker condition utilizing its control circuit data. A risk-based decision approach is proposed at system level making use of the proposed new methodology, for optimizing the maintenance schedules and allocation of resources. This dissertation is focused on developing optimal maintenance strategies for circuit breakers, both at component and system level. A probabilistic maintenance model is proposed using similar approach recently introduced for power transformers. Probabilistic models give better insight into the interplay among monitoring techniques, failure modes and maintenance techniques of the component. The model is based on the concept of representing the component life time by several deterioration stages. Inspection and maintenance is introduced at each stage and model parameters are defined. A sensitivity analysis is carried to understand the importance of model parameters in obtaining optimal maintenance strategies. The analysis covers the effect of inspection rate calculated for each stage and its impact on failure probability, inspection cost, maintenance cost and failure cost. This maintenance model is best suited for long-term maintenance planning. All simulations are carried in MATLAB and how the analysis results may be used to achieve optimal maintenance schedules is discussed. A new methodology is proposed to convert data from the control circuit of a breaker into condition of the breaker by defining several performance indices for breaker assemblies. Control circuit signal timings are extracted and a probability distribution is fitted to each timing parameter. Performance indices for various assemblies such as, trip coil, close coil, auxiliary contacts etc. are defined based on the probability distributions. These indices are updated using Bayesian approach as the new data arrives. This process can be made practical by approximating the Bayesian approach calculating the indices on-line. The quantification of maintenance is achieved by computing the indices after a maintenance action and comparing with those of previously estimated ones. A risk-based decision approach to maintenance planning is proposed based on the new methodology developed for maintenance quantification. A list of events is identified for the test system under consideration, and event probability, event consequence, and hence the risk associated with each event is computed. Optimal maintenance decisions are taken based on the computed risk levels for each event. Two case studies are presented to evaluate the performance of the proposed new methodology for maintenance quantification. The risk-based decision approach is tested on IEEE Reliability Test System. All simulations are carried in MATLAB and the discussions of results are provided.

Natti, Satish

2008-12-01T23:59:59.000Z

420

From the Optimizing Thermostat to a Smart Energy Management System: Models,  

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

From the Optimizing Thermostat to a Smart Energy Management System: Models, From the Optimizing Thermostat to a Smart Energy Management System: Models, Benchmark, and Insights Speaker(s): Yong Liang Date: May 1, 2012 - 12:00pm Location: 90-3122 Seminar Host/Point of Contact: Janie Page Nowadays, users in the retail electricity market only need to pay a fixed rate for electricity. This strategy results in lack of coordination between demand and supply and costs significant waste. A shift from fixed rate pricing in retail markets could potentially yield many benefits. Time-varying pricing promotes the substitution of off-peak consumption for peak consumption, reducing strain on the electrical system, the need for costly and inefficient "peaker" plants, and waste in electricity delivery. However, existing research supports what common sense suggests:

Note: This page contains sample records for the topic "dynamic optimization model" 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

A Unified Technique for Dynamic Modeling and Stability Analysis of Microgrid Systems.  

E-Print Network (OSTI)

??This work presents a unified method for dynamic modeling and stability analysis of microgrid power systems. Using the automated state-model generation algorithm, a state-space model… (more)

Johnson, Brian B.

2010-01-01T23:59:59.000Z

422

Improved representation of tropical Pacific ocean-atmosphere dynamics in an intermediate complexity climate model  

Science Conference Proceedings (OSTI)

A new anomaly coupling technique is introduced into a coarse-resolution dynamic climate model (LOVECLIM), improving the model’s representation of eastern equatorial Pacific surface temperature variability. The anomaly coupling amplifies the ...

Ryan L. Sriver; Axel Timmermann; Michael E. Mann; Klaus Keller; Hugues Goosse

423

Oceanic Rossby Wave Dynamics and the ENSO Period in a Coupled Model  

Science Conference Proceedings (OSTI)

Tropical ocean wave dynamics associated with the El Niño–Southern Oscillation cycle in a coupled model are examined. The ocean–atmosphere model consists of statistical atmosphere coupled to a simple reduced gravity model of the tropical Pacific ...

Ben P. Kirtman

1997-07-01T23:59:59.000Z

424

Transient Climate Change in the CSIRO Coupled Model with Dynamic Sea Ice  

Science Conference Proceedings (OSTI)

The CSIRO coupled model has been used in a “transient” greenhouse experiment. This model contains atmospheric, oceanic, comprehensive sea-ice (dynamic/thermodynamic plus leads), and biospheric submodels. The model control run (over 100 years long)...

Hal B. Gordon; Siobhan P. O’Farrell

1997-05-01T23:59:59.000Z

425

HIGH DETAIL STATIONARY OPTIMIZATION MODELS FOR GAS NETWORKS --PART 1: MODEL COMPONENTS.  

E-Print Network (OSTI)

SCHMIDT, MARC C. STEINBACH, BERNHARD M. WILLERT Abstract. Economic reasons and the regulation of gas markets create a growing need for mathematical optimization in natural gas networks. Real life planning after fixing discrete decisions with coarsely approximated physics. 1. Introduction Natural gas plays

Steinbach, Marc

426

Optimizing counter-terror operations: Should one fight fire with "fire" or "water"?  

Science Conference Proceedings (OSTI)

This paper deals dynamically with the question of how recruitment to terror organizations is influenced by counter-terror operations. This is done within an optimal control model, where the key state is the (relative) number of terrorists and the key ... Keywords: Counter-terror, Epidemic modeling, Optimal dynamic control, Terrorism

Jonathan P. Caulkins; Dieter Grass; Gustav Feichtinger; Gernot Tragler

2008-06-01T23:59:59.000Z

427

An optimized model and test of the China's first high temperature parabolic trough solar receiver  

SciTech Connect

The vacuum solar receiver is the key component of a parabolic trough solar plant, which plays a prominent role in the gross system efficiency. Recently, China's first high temperature vacuum receiver, Sanle-3 HCE, has been developed and produced by Southeast University and Sanle Electronic Group. Before being utilized in China's first parabolic trough solar plant, accurately estimating the thermal properties of this new receiver is important. This paper first establishes and optimizes a 1-D theoretical model at Matlab program to compute the receiver's major heat loss through glass envelope, and then systematically analyzes the major influence factors of heat loss. With the laboratorial steady state test stand, the heat losses of both good vacuum and non-vacuum Sanle-3 receivers were surveyed. Comparison shows the original 1-D model agrees with the ends covered test while remarkably deviating from end exposed test. For the purpose of identifying the influence of receiver's end to total heat loss, an additional 3-D model is built by CFD software to further investigate the different heat transfer processes of receiver's end components. The 3-D end model is verified by heating power and IR temperature distribution images in the test. Combining the optimized 1-D model with the new 3-D end model, the comparison with test data shows a good accordance. At the same time the heat loss curve and emittance curve of this new receiver are given and compared with those of several other existing receivers as references. (author)

Gong, Guangjie; Huang, Xinyan; Wang, Jun; Hao, Menglong [Southeast University, Nanjing (China)

2010-12-15T23:59:59.000Z

428

A Model for the Dynamics of Gene Networks  

E-Print Network (OSTI)

In this work we propose a model for gene expression based on the theory of random dynamical systems (RDS) and show that it has a "modularity property" in the following sense: given any collection of genes that are linked in a transcriptional network, if each of them is individually described by a certain class of RDS then there is a natural, and essentially unique, prescription for coupling them together, respecting the network topology, in such a way that the collective system formed by all genes is a RDS as well. Moreover, the class of RDS used to describe the individual genes is flexible enough to account for a wide range of stochastic behaviors within the realm of stationary processes.

Fernando Antoneli; Renata C. Ferreira; Francisco Bosco; Marcelo R. S. Briones

2013-05-14T23:59:59.000Z

429

Hydro-dynamical models for the chaotic dripping faucet  

E-Print Network (OSTI)

We give a hydrodynamical explanation for the chaotic behaviour of a dripping faucet using the results of the stability analysis of a static pendant drop and a proper orthogonal decomposition (POD) of the complete dynamics. We find that the only relevant modes are the two classical normal forms associated with a Saddle-Node-Andronov bifurcation and a Shilnikov homoclinic bifurcation. This allows us to construct a hierarchy of reduced order models including maps and ordinary differential equations which are able to qualitatively explain prior experiments and numerical simulations of the governing partial differential equations and provide an explanation for the complexity in dripping. We also provide a new mechanical analogue for the dripping faucet and a simple rationale for the transition from dripping to jetting modes in the flow from a faucet.

P. Coullet; L. Mahadevan; C. S. Riera

2004-08-20T23:59:59.000Z

430

Optimal tiling for the RNA base pairing problem  

Science Conference Proceedings (OSTI)

Dynamic programming is an important combinatorial optimization technique that has been widely used in various fields such as control theory, operations research, computational biology and computer science. Many authors have described parallel dynamic ... Keywords: BSP model, MPI, RNA secondary structure prediction, SPMD, dynamic programming, granularity on distributed memory machines, loop partitioning

Francisco Almeida; Rumen Andonov; Daniel Gonzalez; Luz M. Moreno; Vincent Poirriez; Casiano Rodriguez

2002-08-01T23:59:59.000Z

431

A Numerical Model for the Dynamic Simulation of a Recirculation Single-Effect Absorption Chiller  

E-Print Network (OSTI)

A Numerical Model for the Dynamic Simulation of a Recirculation Single- Effect Absorption Chiller A dynamic model for the simulation of a new single-effect water/lithium bromide absorption chiller. Keywords: absorption; chiller; modelling; transient; water-lithium bromide; falling film hal-00713904

Recanati, Catherine

432

USING BOX-JENKINS MODELS TO FORECAST FISHERY DYNAMICS: IDENTIFICATION, ESTIMATION, AND CHECKING  

E-Print Network (OSTI)

USING BOX-JENKINS MODELS TO FORECAST FISHERY DYNAMICS: IDENTIFICATION, ESTIMATION, AND CHECKING Roy MENDELSSOHN! ABSTRACT Box·Jenkins models are suggested as appropriate models for forecasting fishery dynamics in Hawaii. An actual 12-month forecast is shown to give a reasonable fit to the observed data. Most

433

Development of an adaptive fuzzy logic-based inverse dynamic model for laser cladding process  

Science Conference Proceedings (OSTI)

The precision, performance, and robustness of model-based controllers depend, to a large extent, on the accuracy of the inverse dynamic model which is incorporated in the design of the controller. Due to complex nature of the laser cladding process and ... Keywords: Adaptive fuzzy modelling, Fuzzy c-means clustering, Inverse dynamic, Laser cladding

Meysar Zeinali; Amir Khajepour

2010-12-01T23:59:59.000Z

434

Bayesian Inference in Dynamic Disequilibrium Models: An Application to the Polish Credit Market  

E-Print Network (OSTI)

We review Bayesian inference for dynamic latent variable models using the data augmentation principle. We detail the difficulties of simulating dynamic latent variables in a Gibbs sampler. We propose an alternative specification of the dynamic disequilibrium model which leads to a simple simulation procedure and renders Bayesian inference fully operational. Identification issues are discussed. We conduct a specification search using the posterior deviance criterion of Spiegelhalter, Best, Carlin, and van der Linde (2002) for a disequilibrium model of the Polish credit market.

Luc Bauwens; Michel Lubrano

2006-01-01T23:59:59.000Z

435

Uncovering land-use dynamics driven by human decision-making - A combined model approach using cellular automata and system dynamics  

Science Conference Proceedings (OSTI)

This paper introduces an enhancement of a cellular automata (CA) model by integrating system dynamics (SD) to incorporate household dynamics and housing decisions as driving forces of residential development. CA macro-models used to simulate the quantitative ... Keywords: Berlin, Cellular automata, Residential choice, Shrinkage, System dynamics, Urban land use modeling

S. Lauf; D. Haase; P. Hostert; T. Lakes; B. Kleinschmit

2012-01-01T23:59:59.000Z

436

Robustness and Errors in Quantum Optimal Control  

E-Print Network (OSTI)

We introduce a new approach to quantify the robustness of optimal control of closed quantum systems. Our theory allows to assess the degree of distortion that can be applied to a set of known optimal control parameters, which are solutions of an optimal control problem. The formalism is applied to an exactly solvable model and to the Landau-Zener model, whose optimal control problem is solvable only numerically. The presented method is of importance for any application where a high degree of controllability of the quantum system dynamics is required.

Calarco, Antonio Negretti; Rosario Fazio; Tommaso

2010-01-01T23:59:59.000Z

437

Identification and Development of a Model of Railway Track Dynamic Behaviour.  

E-Print Network (OSTI)

??The research presented in this thesis has identified and developed a sophisticated computer model for the analysis of railway track dynamic behaviour to be used… (more)

Steffens, David Martyn

2005-01-01T23:59:59.000Z

438

Spatio-temporal pattern formation in coupled models of plankton dynamics and fish school motion  

Science Conference Proceedings (OSTI)

Keywords: bistability, chaos, plankton dynamics, predator-prey model, reaction-diffusion system, rule-based fish school motion, spiral waves

Horst Malchow; Birgit Radtke; Malaak Kallache; Alexander B. Medvinsky; Dmitry A. Tikhonov; Sergei V. Petrovskii

2000-03-01T23:59:59.000Z

439

Dynamics Modeling and Loads Analysis of an Offshore Floating Wind Turbine  

SciTech Connect

This report describes the development, verification, and application of a comprehensive simulation tool for modeling coupled dynamic responses of offshore floating wind turbines.

Jonkman, J. M.

2007-12-01T23:59:59.000Z

440

Horizontal Momentum Diffusion in GCMs Using the Dynamic Smagorinsky Model  

Science Conference Proceedings (OSTI)

A dynamic version of Smagorinsky’s diffusion scheme is presented that is applicable for large-eddy simulations (LES) of the atmospheric dynamics. The approach is motivated (i) by the incompatibility of conventional hyperdiffusion schemes with the ...

Urs Schaefer-Rolffs; Erich Becker

2013-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamic optimization model" 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

A multiperiod optimization model to schedule large-scale petroleum development projects  

E-Print Network (OSTI)

This dissertation solves an optimization problem in the area of scheduling large-scale petroleum development projects under several resources constraints. The dissertation focuses on the application of a metaheuristic search Genetic Algorithm (GA) in solving the problem. The GA is a global search method inspired by natural evolution. The method is widely applied to solve complex and sizable problems that are difficult to solve using exact optimization methods. A classical resource allocation problem in operations research known under Knapsack Problems (KP) is considered for the formulation of the problem. Motivation of the present work was initiated by certain petroleum development scheduling problem in which large-scale investment projects are to be selected subject to a number of resources constraints in several periods. The constraints may occur from limitations in various resources such as capital budgets, operating budgets, and drilling rigs. The model also accounts for a number of assumptions and business rules encountered in the application that motivated this work. The model uses an economic performance objective to maximize the sum of Net Present Value (NPV) of selected projects over a planning horizon subject to constraints involving discrete time dependent variables. Computational experiments of 30 projects illustrate the performance of the model. The application example is only illustrative of the model and does not reveal real data. A Greedy algorithm was first utilized to construct an initial estimate of the objective function. GA was implemented to improve the solution and investigate resources constraints and their effect on the assets value. The timing and order of investment decisions under constraints have the prominent effect on the economic performance of the assets. The application of an integrated optimization model provides means to maximize the financial value of the assets, efficiently allocate limited resources and to analyze more scheduling alternatives in less time.

Husni, Mohammed Hamza

2008-12-01T23:59:59.000Z

442

Creating dynamic equivalent PV circuit models with impedance spectroscopy for arc-fault modeling.  

Science Conference Proceedings (OSTI)

Article 690.11 in the 2011 National Electrical Code{reg_sign} (NEC{reg_sign}) requires new photovoltaic (PV) systems on or penetrating a building to include a listed arc fault protection device. Currently there is little experimental or empirical research into the behavior of the arcing frequencies through PV components despite the potential for modules and other PV components to filter or attenuate arcing signatures that could render the arc detector ineffective. To model AC arcing signal propagation along PV strings, the well-studied DC diode models were found to inadequately capture the behavior of high frequency arcing signals. Instead dynamic equivalent circuit models of PV modules were required to describe the impedance for alternating currents in modules. The nonlinearities present in PV cells resulting from irradiance, temperature, frequency, and bias voltage variations make modeling these systems challenging. Linearized dynamic equivalent circuits were created for multiple PV module manufacturers and module technologies. The equivalent resistances and capacitances for the modules were determined using impedance spectroscopy with no bias voltage and no irradiance. The equivalent circuit model was employed to evaluate modules having irradiance conditions that could not be measured directly with the instrumentation. Although there was a wide range of circuit component values, the complex impedance model does not predict filtering of arc fault frequencies in PV strings for any irradiance level. Experimental results with no irradiance agree with the model and show nearly no attenuation for 1 Hz to 100 kHz input frequencies.

Johnson, Jay Dean; Kuszmaul, Scott S.; Strauch, Jason E.; Schoenwald, David Alan

2011-06-01T23:59:59.000Z

443

Optimal Cluster Mill Pass Scheduling With an Accurate and Rapid New Strip Crown Model  

Science Conference Proceedings (OSTI)

Besides the requirement to roll coiled sheet at high levels of productivity, the optimal pass scheduling of cluster-type reversing cold mills presents the added challenge of assigning mill parameters that facilitate the best possible strip flatness. The pressures of intense global competition, and the requirements for increasingly thinner, higher quality specialty sheet products that are more difficult to roll, continue to force metal producers to commission innovative flatness-control technologies. This means that during the on-line computerized set-up of rolling mills, the mathematical model should not only determine the minimum total number of passes and maximum rolling speed, it should simultaneously optimize the pass-schedule so that desired flatness is assured, either by manual or automated means. In many cases today, however, on-line prediction of strip crown and corresponding flatness for the complex cluster-type rolling mills is typically addressed either by trial and error, by approximate deflection models for equivalent vertical roll-stacks, or by non-physical pattern recognition style models. The abundance of the aforementioned methods is largely due to the complexity of cluster-type mill configurations and the lack of deflection models with sufficient accuracy and speed for on-line use. Without adequate assignment of the pass-schedule set-up parameters, it may be difficult or impossible to achieve the required strip flatness. In this paper, we demonstrate optimization of cluster mill pass-schedules using a new accurate and rapid strip crown model. This pass-schedule optimization includes computations of the predicted strip thickness profile to validate mathematical constraints. In contrast to many of the existing methods for on-line prediction of strip crown and flatness on cluster mills, the demonstrated method requires minimal prior tuning and no extensive training with collected mill data. To rapidly and accurately solve the multi-contact problem and predict the strip crown, a new customized semi-analytical modeling technique that couples the Finite Element Method (FEM) with classical solid mechanics was developed to model the deflection of the rolls and strip while under load. The technique employed offers several important advantages over traditional methods to calculate strip crown, including continuity of elastic foundations, non-iterative solution when using predetermined foundation moduli, continuous third-order displacement fields, simple stress-field determination, and a comparatively faster solution time.

Malik, Arif S.; Grandhi, Ramana V. [Dept. of Mechanical Engineering, Wright State University, 3640 Col. Glenn Hwy., Dayton, OH 45435 (United States); Zipf, Mark E. [Intergrated Industrial Systems, Inc., 475 Main St., Yalesville, CT 06492 (United States)

2007-05-17T23:59:59.000Z

444

Abstract--An optimization model that incorporates demand in the paradigm of smart grids and distributed generation is  

E-Print Network (OSTI)

, Maximum expected demand in the optimization period Cost associated to energy generated by demand from1 Abstract--An optimization model that incorporates demand in the paradigm of smart grids and distributed generation is formulated. The objective is to transform the demand into an active agent that helps

Catholic University of Chile (Universidad Católica de Chile)

445

Stochastic hydro-economic modeling for optimal management of agricultural groundwater nitrate pollution under hydraulic conductivity uncertainty  

Science Conference Proceedings (OSTI)

In decision-making processes, reliability and risk aversion play a decisive role. This paper presents a framework for stochastic optimization of control strategies for groundwater nitrate pollution from agriculture under hydraulic conductivity uncertainty. ... Keywords: Fertilizer allocation, Groundwater, Nitrates, Optimization, Stochastic management model, Uncertainty

S. Peña-Haro; M. Pulido-Velazquez; C. Llopis-Albert

2011-08-01T23:59:59.000Z

446

AIR INGRESS ANALYSIS: PART 2 – COMPUTATIONAL FLUID DYNAMIC MODELS  

Science Conference Proceedings (OSTI)

The Idaho National Laboratory (INL), under the auspices of the U.S. Department of Energy, is performing research and development that focuses on key phenomena important during potential scenarios that may occur in very high temperature reactors (VHTRs). Phenomena Identification and Ranking Studies to date have ranked an air ingress event, following on the heels of a VHTR depressurization, as important with regard to core safety. Consequently, the development of advanced air ingress-related models and verification and validation data are a very high priority. Following a loss of coolant and system depressurization incident, air will enter the core of the High Temperature Gas Cooled Reactor through the break, possibly causing oxidation of the in-the core and reflector graphite structure. Simple core and plant models indicate that, under certain circumstances, the oxidation may proceed at an elevated rate with additional heat generated from the oxidation reaction itself. Under postulated conditions of fluid flow and temperature, excessive degradation of the lower plenum graphite can lead to a loss of structural support. Excessive oxidation of core graphite can also lead to the release of fission products into the confinement, which could be detrimental to a reactor safety. Computational fluid dynamic model developed in this study will improve our understanding of this phenomenon. This paper presents two-dimensional and three-dimensional CFD results for the quantitative assessment of the air ingress phenomena. A portion of results of the density-driven stratified flow in the inlet pipe will be compared with results of the experimental results.

Chang H. Oh; Eung S. Kim; Richard Schultz; Hans Gougar; David Petti; Hyung S. Kang

2011-01-01T23:59:59.000Z

447

Multidataset Study of Optimal Parameter and Uncertainty Estimation of a Land Surface Model with Bayesian Stochastic Inversion and Multicriteria Method  

Science Conference Proceedings (OSTI)

This study evaluates the ability of Bayesian stochastic inversion (BSI) and multicriteria (MC) methods to search for the optimal parameter sets of the Chameleon Surface Model (CHASM) using prescribed forcing to simulate observed sensible and ...

Youlong Xia; Mrinal K. Sen; Charles S. Jackson; Paul L. Stoffa

2004-10-01T23:59:59.000Z

448

Impact of Geographic-Dependent Parameter Optimization on Climate Estimation and Prediction: Simulation with an Intermediate Coupled Model  

Science Conference Proceedings (OSTI)

Because of the geographic dependence of model sensitivities and observing systems, allowing optimized parameter values to vary geographically may significantly enhance the signal in parameter estimation. Using an intermediate atmosphere–ocean–land ...

Xinrong Wu; Shaoqing Zhang; Zhengyu Liu; Anthony Rosati; Thomas L. Delworth; Yun Liu

2012-12-01T23:59:59.000Z

449

Development of an entrained flow gasifier model for process optimization study  

SciTech Connect

Coal gasification is a versatile process to convert a solid fuel in syngas, which can be further converted and separated in hydrogen, which is a valuable and environmentally acceptable energy carrier. Different technologies (fixed beds, fluidized beds, entrained flow reactors) are used, operating under different conditions of temperature, pressure, and residence time. Process studies should be performed for defining the best plant configurations and operating conditions. Although 'gasification models' can be found in the literature simulating equilibrium reactors, a more detailed approach is required for process analysis and optimization procedures. In this work, a gasifier model is developed by using AspenPlus as a tool to be implemented in a comprehensive process model for the production of hydrogen via coal gasification. It is developed as a multizonal model by interconnecting each step of gasification (preheating, devolatilization, combustion, gasification, quench) according to the reactor configuration, that is in entrained flow reactor. The model removes the hypothesis of equilibrium by introducing the kinetics of all steps and solves the heat balance by relating the gasification temperature to the operating conditions. The model allows to predict the syngas composition as well as quantity the heat recovery (for calculating the plant efficiency), 'byproducts', and residual char. Finally, in view of future works, the development of a 'gasifier model' instead of a 'gasification model' will allow different reactor configurations to be compared.

Biagini, E.; Bardi, A.; Pannocchia, G.; Tognotti, L. [Consorzio Pisa Ric, Pisa (Italy). Div Energia Ambiente

2009-10-15T23:59:59.000Z

450

A Double Fourier Series (DFS) Dynamical Core in a Global Atmospheric Model with Full Physics  

Science Conference Proceedings (OSTI)

This study describes an application of the double Fourier series (DFS) spectral method developed by Cheong as an alternative dynamical option in a model system that was ported into the Global/Regional Integrated Model System (GRIMs). A message ...

Hoon Park; Song-You Hong; Hyeong-Bin Cheong; Myung-Seo Koo

2013-09-01T23:59:59.000Z

451

A Coupled Dynamical Ocean–Energy Balance Atmosphere Model for Paleoclimate Studies  

Science Conference Proceedings (OSTI)

The Bern3D coupled three-dimensional dynamical ocean–energy balance atmosphere model is introduced and the atmospheric component is discussed in detail. The model is of reduced complexity, developed to perform extensive sensitivity studies and ...

Stefan P. Ritz; Thomas F. Stocker; Fortunat Joos

2011-01-01T23:59:59.000Z

452

Dynamic Surface Interface Exchanges of Mercury: A Review and Compartmentalized Modeling Framework  

Science Conference Proceedings (OSTI)

This paper presents a review of recent natural surface mercury exchange research in the context of a new modeling framework. The literature indicates that the mercury biogeochemical flux is more dynamic than the current models predict, with ...

Jesse O. Bash; Patricia Bresnahan; David R. Miller

2007-10-01T23:59:59.000Z

453

Dynamic modeling of planar parallel robots considering passive joint sensor data  

Science Conference Proceedings (OSTI)

Model-based advanced control approaches are needed to achieve high speed and acceleration and precision in robotic operations. These control schemes need a proper dynamic model. Many approaches have been proposed by different authors in order to obtain ...

Asier Zubizarreta; Itziar Cabanes; Marga Marcos; Charles Pinto

2010-09-01T23:59:59.000Z

454

Boundary Layer Dynamics in a Simple Model for Convectively Coupled Gravity Waves  

Science Conference Proceedings (OSTI)

A simplified model of intermediate complexity for convectively coupled gravity waves that incorporates the bulk dynamics of the atmospheric boundary layer is developed and analyzed. The model comprises equations for velocity, potential ...

Michael L. Waite; Boualem Khouider

2009-09-01T23:59:59.000Z

455

A Double Fourier Series (DFS) Dynamic Core in a Global Atmospheric Model with Full Physics  

Science Conference Proceedings (OSTI)

This study describes an application of the double Fourier series (DFS) spectral method developed by Cheong (2006) as an alternative dynamic option in a model system that was ported in the Global/Regional Integrated Model system (GRIMs). A message-...

Hoon Park; Song-You Hong; Hyeong-Bin Cheong; Myung-Seo Koo

456

Networking technology adoption : system dynamics modeling of fiber-to-the-home  

E-Print Network (OSTI)

A system dynamics model is developed and run to study the adoption of fiber-to-the-home as a residential broadband technology. Communities that currently do not have broadband in the United States are modeled. This case ...

Kelic, Andjelka, 1972-

2005-01-01T23:59:59.000Z

457

Dynamics and Thermodynamics of a Warming Event in a Coupled Tropical Atmosphere–Ocean Model  

Science Conference Proceedings (OSTI)

A simple coupled ocean–atmosphere model, similar to that of Zebiak and Cane, is used to examine the dynamic and thermodynamic processes associated with El Niño/Southern Oscillation (ENSO). The model is run for 300 years. The interannual ...

David S. Battisti

1988-10-01T23:59:59.000Z

458

Ensemble Simulations with Coupled Atmospheric Dynamic and Dispersion Models: Illustrating Uncertainties in Dosage Simulations  

Science Conference Proceedings (OSTI)

Ensemble simulations made using a coupled atmospheric dynamic model and a probabilistic Lagrangian puff dispersion model were employed in a forensic analysis of the transport and dispersion of a toxic gas that may have been released near Al ...

Thomas T. Warner; Rong-Shyang Sheu; James F. Bowers; R. Ian Sykes; Gregory C. Dodd; Douglas S. Henn

2002-05-01T23:59:59.000Z

459

Designing of integrated system-dynamics models for an oil company  

Science Conference Proceedings (OSTI)

This paper presents a new approach to designing integrated simulation models for large corporations. This approach is based on the use of system-dynamics methods for implementing models of segments of the vertically integrated company taking into account ...

Andranik S. Akopov

2012-12-01T23:59:59.000Z

460

Modeling the Atmospheric General Circulation Using a Spherical Geodesic Grid: A New Class of Dynamical Cores  

Science Conference Proceedings (OSTI)

This paper documents the development and testing of a new type of atmospheric dynamical core. The model solves the vorticity and divergence equations in place of the momentum equation. The model is discretized in the horizontal using a geodesic ...

Todd D. Ringler; Ross P. Heikes; David A. Randall

2000-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamic optimization model" 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

Dynamical Core of an Atmospheric General Circulation Model on a Yin–Yang Grid  

Science Conference Proceedings (OSTI)

The three-dimensional dynamical core of an atmospheric general circulation model employing Yin–Yang grid is developed and examined. Benchmark test cases based on the shallow-water model configuration are first performed to examine the validity of ...

Yuya Baba; Keiko Takahashi; Takeshi Sugimura; Koji Goto

2010-10-01T23:59:59.000Z

462

Toward Dynamic, Longitudinal, Agent-Based Microsimulation Models of Human Activity in Urban Settings  

E-Print Network (OSTI)

for theory. FOCUSING ON INTERACTION USING AGENT-BASED MODELSBackground Agent-based models are characterized by theirEnvironment The dynamic agent-based model seeks to produce,

Rindt, Craig R.; Marca, James E.; McNally, Michael G.

2002-01-01T23:59:59.000Z

463

African Easterly Wave Dynamics in a Mesoscale Numerical Model: The Upscale Role of Convection  

Science Conference Proceedings (OSTI)

To examine the dynamical role of convection in African easterly wave (AEW) life cycles the Weather Research and Forecasting (WRF) model is used to simulate the evolution of a single AEW from September 2004. The model simulations are validated ...

Gareth J. Berry; Chris D. Thorncroft

2012-04-01T23:59:59.000Z

464

Determination of Forecast Errors Arising from Different Components of Model Physics and Dynamics  

Science Conference Proceedings (OSTI)

This paper addresses a procedure to extract error estimates for the physical and dynamical components of a forecast model. This is a two-step process in which contributions to the forecast tendencies from individual terms of the model equations ...

T. N. Krishnamurti; J. Sanjay; A. K. Mitra; T. S. V. Vijaya Kumar

2004-11-01T23:59:59.000Z

465

MATHEMATICAL MODELS OF HYSTERESIS (DYNAMIC PROBLEMS IN HYSTERESIS)  

SciTech Connect

This research has further advanced the current state of the art in the areas of dynamic aspects of hysteresis and nonlinear large scale magnetization dynamics. The results of this research will find important engineering applications in the areas of magnetic data storage technology and the emerging technology of “spintronics”. Our research efforts have been focused on the following tasks: • Study of fast (pulse) precessional switching of magnetization in magnetic materials. • Analysis of critical fields and critical angles for precessional switching of magnetization. • Development of inverse problem approach to the design of magnetic field pulses for precessional switching of magnetization. • Study of magnetization dynamics induced by spin polarized current injection. • Construction of complete stability diagrams for spin polarized current induced magnetization dynamics. • Development of the averaging technique for the analysis of the slow time scale magnetization dynamics. • Study of thermal effects on magnetization dynamics by using the theory of stochastic processes on graphs.

Professor Isaak Mayergoyz

2006-08-21T23:59:59.000Z

466

Optimal cytoplasmatic density and flux balance model under macromolecular crowding effects  

E-Print Network (OSTI)

Macromolecules occupy between 34 and 44% of the cell cytoplasm, about half the maximum pack- ing density of spheres in three dimension. Yet, there is no clear understanding of what is special about this value. To address this fundamental question we investigate the effect of macromolecular crowding on cell metabolism. We develop a cell scale flux balance model capturing the main features of cell metabolism at different nutrient uptakes and macromolecular densities. Using this model we show there are two metabolic regimes at low and high nutrient uptakes. The latter regime is charac- terized by an optimal cytoplasmatic density where the increase of reaction rates by confinement and the decrease by diffusion slow-down balance. More important, the predicted optimal density is in the range of the experimentally determined density of E. coli. We conclude that cells have evolved to a cytoplasmatic density resulting in the maximum metabolic rate given the nutrient availability and macromolecular crowding effects and report a flux balance model accounting for its effect.

Alexei Vazquez

2009-10-11T23:59:59.000Z

467

A Technical Review on Biomass Processing: Densification, Preprocessing, Modeling and Optimization  

SciTech Connect

It is now a well-acclaimed fact that burning fossil fuels and deforestation are major contributors to climate change. Biomass from plants can serve as an alternative renewable and carbon-neutral raw material for the production of bioenergy. Low densities of 40–60 kg/m3 for lignocellulosic and 200–400 kg/m3 for woody biomass limits their application for energy purposes. Prior to use in energy applications these materials need to be densified. The densified biomass can have bulk densities over 10 times the raw material helping to significantly reduce technical limitations associated with storage, loading and transportation. Pelleting, briquetting, or extrusion processing are commonly used methods for densification. The aim of the present research is to develop a comprehensive review of biomass processing that includes densification, preprocessing, modeling and optimization. The specific objective include carrying out a technical review on (a) mechanisms of particle bonding during densification; (b) methods of densification including extrusion, briquetting, pelleting, and agglomeration; (c) effects of process and feedstock variables and biomass biochemical composition on the densification (d) effects of preprocessing such as grinding, preheating, steam explosion, and torrefaction on biomass quality and binding characteristics; (e) models for understanding the compression characteristics; and (f) procedures for response surface modeling and optimization.

Jaya Shankar Tumuluru; Christopher T. Wright

2010-06-01T23:59:59.000Z

468

A simple model of impact dynamics in many dimensional systems, with applications to heat exchangers  

E-Print Network (OSTI)

A simple model of impact dynamics in many dimensional systems, with applications to heat exchangers present a simple hybrid model of impact dynamics in heat exchangers. The method, based on graph theory and experimental evidence. 1 Introduction A heat exchanger typically consists of a large number of thin pipes

Bristol, University of

469

A next-generation modeling capability assesses wind turbine array fluid dynamics and aeroelastic simulations  

E-Print Network (OSTI)

A next-generation modeling capability assesses wind turbine array fluid dynamics and aeroelastic conditions with turbine models covering the range of scales important for wind plant dynamics to help address the impacts that upwind turbines have on turbines in their wake and give greater insight into overall wind

470

Modeling considerations in static and dynamic voltage stability studies of shipboard power systems  

Science Conference Proceedings (OSTI)

Better modeling is a key issue to system analysis and emulating real system performances accurately. This paper addresses modeling considerations and approaches to be taken for voltage stability analysis. Two approaches, static and dynamic analysis, ... Keywords: PSCAD, dynamic analysis, numerical integration method, static analysis, voltage stability

Minglan Lin; Anurag K. Srivastava; Noel N. Schulz

2007-07-01T23:59:59.000Z

471

Linear driving force models for dynamic adsorption of volatile organic compound traces by porous adsorbent beds  

Science Conference Proceedings (OSTI)

Models for the dynamic adsorption of volatile organic compound (VOC) traces in air are considered. They are based on the linear driving force approximation associated with various adsorption isotherms characteristic of the couple VOC-adsorbent (Langmuir, ... Keywords: Comsol, Dubinin-Astakhov isotherm, Dynamic adsorption modelling, Finite element

Agnès Joly; Alain Perrard

2009-08-01T23:59:59.000Z

472

Steady-state power flow modeling for a dynamic voltage restorer  

Science Conference Proceedings (OSTI)

This paper presents analysis, modeling and simulation of power distribution network performance incorporating with an installed dynamic voltage restorer (DVR). DVR is one of series compensators used in power distribution systems in order to maintain ... Keywords: Gauss-Seidel method, dynamic voltage restorer, modeling, power flow, simulation

T. Ratniyomchai; T. Kulworawanichpong

2006-03-01T23:59:59.000Z

473

Molecular Dynamics Model of Ultraviolet Matrix-Assisted Laser Desorption/Ionization Including Ionization Processes  

E-Print Network (OSTI)

Molecular Dynamics Model of Ultraviolet Matrix-Assisted Laser Desorption/Ionization Including A molecular dynamics model of UV-MALDI including ionization processes is presented. In addition/desorption of molecular systems, it includes radiative and nonradiative decay, exciton hopping, two pooling processes

Zhigilei, Leonid V.

474

The implementation of polarizable and flexible models in molecular dynamics simulations  

Science Conference Proceedings (OSTI)

We discuss a new methodology for implementing polarizable and flexible molecular models - the fluctuating charge and intramolecular potential (fCINTRA) method - in Molecular Dynamics (MD) simulations. An example has been provided for ethanol. In these ... Keywords: message passing interface, molecular dynamics simulation, polarizable and flexible model

Shihao Wang; Natalie M. Cann

2009-06-01T23:59:59.000Z

475

From empirical data to mathematical model: using population dynamics to characterize insurgencies  

Science Conference Proceedings (OSTI)

Understanding the nature of insurgencies is critical to determining strategies for mitigating their effects. Modeling insurgencies is one method to provide a structured methodology to gain insight into the various characteristics of insurgencies. This ... Keywords: homeland security, insurgency modeling, population dynamics, system dynamics

John A. Sokolowski; Catherine M. Banks

2007-07-01T23:59:59.000Z

476

Hydraulic Fracture Optimization with a Pseudo-3D Model in Multi-layered Lithology  

E-Print Network (OSTI)

Hydraulic Fracturing is a technique to accelerate production and enhance ultimate recovery of oil and gas while fracture geometry is an important aspect in hydraulic fracturing design and optimization. Systematic design procedures are available based on the so-called two-dimensional models (2D) focus on the optimization of fracture length and width, assuming one can estimate a value for fracture height, while so-called pseudo three dimensional (p-3D) models suitable for multi-layered reservoirs aim to maximize well production by optimizing fracture geometry, including fracture height, half-length and width at the end of the stimulation treatment. The proposed p-3D approach to design integrates four parts: 1) containment layers discretization to allow for a range of plausible fracture heights, 2) the Unified Fracture Design (UFD) model to calculate the fracture half-length and width, 3) the PKN or KGD models to predict hydraulic fracture geometry and the associated net pressure and other treatment parameters, and, finally, 4) Linear Elastic Fracture Mechanics (LEFM) to calculate fracture height. The aim is to find convergence of fracture height and net pressure. Net pressure distribution plays an important role when the fracture is propagating in the reservoir. In multi-layered reservoirs, the net pressure of each layer varies as a result of different rock properties. This study considers the contributions of all layers to the stress intensity factor at the fracture tips to find the final equilibrium height defined by the condition where the fracture toughness equals the calculated stress intensity factor based on LEFM. Other than maximizing production, another obvious application of this research is to prevent the fracture from propagating into unintended layers (i.e. gas cap and/or aquifer). Therefore, this study can aid fracture design by pointing out: (1) Treating pressure needed to optimize fracture geometry, (2) The containment top and bottom layers of a multi-layered reservoir, (3) The upwards and downwards growth of the fracture tip from the crack center.

Yang, Mei

2011-08-01T23:59:59.000Z

477

Modeling Resource, Infrastructure, and Policy Cost Layers for Optimizing Renewable Energy Investment and Deployment  

SciTech Connect

This paper presents a framework for creating a common spatial canvass that can bring together considerations of resource availability, infrastructure reliability, and development costs while strategizing renewable energy investment. We describe the underlying models and methodologies that annotate an investment plan for potential sites over a time-period with costs and constraints which may be imposed on distance from infrastructure, system impact on infrastructure, and policy incentives. The framework is intended as an enabler for visualization, optimization and decision making across diverse dimensions while searching for lucrative investment-plans.

Sukumar, Sreenivas R [ORNL; Olama, Mohammed M [ORNL; Shankar, Mallikarjun [ORNL; Hadley, Stanton W [ORNL; Nutaro, James J [ORNL; Protopopescu, Vladimir A [ORNL; Malinchik, Sergey [Lockheed Martin Corporation; Ives, Barry [Lockheed Martin Corporation

2010-01-01T23:59:59.000Z

478

Automatic Calibration of a Building Energy Simulation Model Using a Global Optimization Program  

E-Print Network (OSTI)

A simulation model used to analyze the energy performance of an existing building should be calibrated to measured consumption data from the building so the simulation output closely follows the measured time series energy consumption data and shows the same temperature dependence. This paper has used optimization software to show that a simple simulation program which is a coding of the ASHRAE 'Simplified Energy Analysis Procedure' can be automatically calibrated to “measured” data. The “measured data” used in this case study was simulation data to which a small amount of white noise had been added.

Lee, S. U.; Claridge, D.

2002-01-01T23:59:59.000Z

479

Application of dynamic programming model in inventory management.  

E-Print Network (OSTI)

???This thesis aims to apply dynamic programming approach to formulate three main topics related to inventory management under three real world situations and then propose… (more)

Tao, Feng ( ??)

2011-01-01T23:59:59.000Z

480

Modeling System Development for the Evaluation of Dynamic Air...  

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

supply and demand. The challenges of dynamic analysis of emissions impacts from the energy sector have substantially increased with a new focus on the emerging distributed...

Note: This page contains sample records for the topic "dynamic optimization model" 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.