de Lijser, Peter
1 Staffing Formula Worksheet: How to Choose a Staffing Formula for Your Class Staffing Formulas the choice of Staffing Formula also has consequences for faculty workload, be sure to consult with the chair of your department before submitting your course proposal. The most commonly used Staffing Formulas
Safety System Oversight Staffing Analysis (Instructions, Blank...
Office of Environmental Management (EM)
modifications since changes to the worksheet format may inadvertently change included formula referenced cells. SSO Alternate Staffing Analysis - Instructions SSO Alternate...
2012 Workforce Analysis and Staffing Plan Report Memo, Guidance...
Office of Environmental Management (EM)
Workforce Analysis and Staffing Plan Report Memo, Guidance and Template 2012 Workforce Analysis and Staffing Plan Report Memo, Guidance and Template The Department of Energy...
2011 Workforce Analysis and Staffing Plan Report Memo, Guidance...
Office of Environmental Management (EM)
Workforce Analysis and Staffing Plan Report Memo, Guidance and Template 2011 Workforce Analysis and Staffing Plan Report Memo, Guidance and Template The Department of Energy...
2013 Workforce Analysis and Staffing Plan Report Memo, Guidance...
Office of Environmental Management (EM)
3 Workforce Analysis and Staffing Plan Report Memo, Guidance and Template 2013 Workforce Analysis and Staffing Plan Report Memo, Guidance and Template The Department of Energy...
Human Resources Staffing Plan for the Tank Farm Contractor
BOSLEY, J.W.
2000-04-22
The Human Resources Staffing Plan quantified the equivalent staffing needs required for the Tank Farm Contractor (TFC) and its subcontractors to execute the readiness to proceed baseline between FY 2000-2008. The TFC staffing needs were assessed along with the staffings needs of Fluor Hanford and the privatization contractor. The plan then addressed the staffing needs and recruitment strategies required to execute the baseline.
2014 Annual Workforce Analysis and Staffing Plan Report - Portsmouth...
Office of Environmental Management (EM)
Office Annual Workforce Analysis and Staffing Plan Report for SUBJECT: Calendar Year 2014 TO: Ms. Karen Boardman, Chair Federal Technical Capability Panel, EA-50383 Reference:...
2013 Annual Workforce Analysis and Staffing Plan Report - NNSA...
Office of Environmental Management (EM)
NNSA Production Office 2013 Annual Workforce Analysis and Staffing Plan Report - NNSA Production Office Managers perform an annual workforce analysis of their organization and...
2010 Workforce Analysis and Staffing Plan Report Memo, Guidance...
Broader source: Energy.gov (indexed) [DOE]
The Department of Energy Federal Technical Capability Order, DOE 0 426.1, requires that managers perform an annual workforce analysis of their organization and develop staffing...
2012 Annual Workforce Analysis and Staffing Plan Report - Nevada...
Plan Report - Nevada Site Office 2012 Annual Workforce Analysis and Staffing Plan Report - Nevada Site Office Managers perform an annual workforce analysis of their...
2014 Workforce Analysis and Staffing Plan Report Memo, Guidance...
Broader source: Energy.gov (indexed) [DOE]
The Department of Energy Federal Technical Capability Order, DOE O 426.1, requires that managers perform an annual workforce analysis of their organization and develop staffing...
2014 Annual Workforce Analysis and Staffing Plan Report - Carlsbad...
Plan Report - Carlsbad Field Office 2014 Annual Workforce Analysis and Staffing Plan Report - Carlsbad Field Office Managers perform an annual workforce analysis of their...
2010 Annual Workforce Analysis and Staffing Plan Report - Los...
Plan Report - Los Alamos Site Office 2010 Annual Workforce Analysis and Staffing Plan Report - Los Alamos Site Office Managers perform an annual workforce analysis of their...
2011 Annual Workforce Analysis and Staffing Plan Report - Carlsbad...
Plan Report - Carlsbad Field Office 2011 Annual Workforce Analysis and Staffing Plan Report - Carlsbad Field Office Managers perform an annual workforce analysis of their...
2012 Annual Workforce Analysis and Staffing Plan Report - Carlsbad...
Plan Report - Carlsbad Field Office 2012 Annual Workforce Analysis and Staffing Plan Report - Carlsbad Field Office Managers perform an annual workforce analysis of their...
2013 Annual Workforce Analysis and Staffing Plan Report - Livermore...
Plan Report - Livermore Field Office 2013 Annual Workforce Analysis and Staffing Plan Report - Livermore Field Office Managers perform an annual workforce analysis of their...
2014 Annual Workforce Analysis and Staffing Plan Report - Nevada...
Plan Report - Nevada Field Office 2014 Annual Workforce Analysis and Staffing Plan Report - Nevada Field Office Managers perform an annual workforce analysis of their...
Nurse Absenteeism and Staffing Strategies for Hospital Inpatient Units
Gupta, Diwakar
for subpopulations such as cardiac and vascular, surgical, trauma, and pediatric patients. Nurses whose skillsNurse Absenteeism and Staffing Strategies for Hospital Inpatient Units Wen-Ya Wang1 , Diwakar Gupta Engineering Department, University of Minnesota Inpatient staffing costs are significantly affected by nurse
2010 Annual Workforce Analysis and Staffing Plan Report- NNSA HQ
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2014 Annual Workforce Analysis and Staffing Plan Report- NNSA HQ
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2011 Annual Workforce Analysis and Staffing Plan Report- NNSA HQ
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2013 Annual Workforce Analysis and Staffing Plan Report- NNSA HQ
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
Do You Have Adequate Staffing to Keep Costs Under Control?
Mergens, E. H.
1989-01-01
business, yet the management emphasis is on maintenance expenditures with considerably less on the other categories. Several other plants are in this company organization which were available for comparison. This is shown in Chart 5. The capacity... STAFFING TO KEEP COSTS UNDER CONTROL? E. H. MERGENS Manager, Energy Conservation Shell Oil Company Houston, Texas ABSTRACT As visual illustration of the revised staffing is shown in Charts 1 and 2. As Competitive pressures have forced companies...
To request the approval of a new Staffing and Placing Order under DOE O 325.3
Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]
2015-11-05
To create a new Staffing and Placement order that will establish policies and other requirements relating to internal and external staffing and recruitment practices.
Staffing for Clean Energy Financing Programs | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious RankADVANCED MANUFACTURINGEnergy BillsNo.Hydrogen4EnergySolidof2 SpecialSpent|Staffing for Clean Energy
2014 Annual Workforce Analysis and Staffing Plan Report- Office of Environmental Management
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2013 Annual Workforce Analysis and Staffing Plan Report- Idaho Operations Office
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2014 Annual Workforce Analysis and Staffing Plan Report- Savannah River Operations Office
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2014 Annual Workforce Analysis and Staffing Plan Report- Office of River Protection
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2013 Annual Workforce Analysis and Staffing Plan Report- Chief of Nuclear Safety
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2014 Annual Workforce Analysis and Staffing Plan Report- Chief of Nuclear Safety
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2014 Annual Workforce Analysis and Staffing Plan Report- Office of Science
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2013 Annual Workforce Analysis and Staffing Plan Report- Office of Science
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2012 Annual Workforce Analysis and Staffing Plan Report- Office of Science
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2011 Annual Workforce Analysis and Staffing Plan Report- Office of Science
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2013 Annual Workforce Analysis and Staffing Plan Report- Office of Science Chicago Office
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2010 Annual Workforce Analysis and Staffing Plan Report- Office of Science
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2013 Annual Workforce Analysis and Staffing Plan Report- Nuclear Energy Oak Ridge Site Office
Broader source: Energy.gov [DOE]
anagers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2013 Annual Workforce Analysis and Staffing Plan Report- Oak Ridge Office
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2012 Annual Workforce Analysis and Staffing Plan Report- Oak Ridge Office
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2010 Annual Workforce Analysis and Staffing Plan Report- Y-12 Site Office
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2011 Annual Workforce Analysis and Staffing Plan Report- Chief of Nuclear Safety
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2014 Annual Workforce Analysis and Staffing Plan Report- Idaho Operations Office
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2012 Annual Workforce Analysis and Staffing Plan Report- Los Alamos Field Office
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2014 Annual Workforce Analysis and Staffing Plan Report- Los Alamos Field Office
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2011 Annual Workforce Analysis and Staffing Plan Report- Los Alamos Site Office
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2013 Annual Workforce Analysis and Staffing Plan Report- Los Alamos Field Office
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2014 Annual Workforce Analysis and Staffing Plan Report- Savannah River Field Office
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2013 Annual Workforce Analysis and Staffing Plan Report- Pacific Northwest Site Office
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2011 Annual Workforce Analysis and Staffing Plan Report- Savannah River Site Office
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
The association between nurse staffing and hospital outcomes in injured patients
Glance, Laurent G; Dick, Andrew W; Osler, Turner M; Mukamel, Dana B; Li, Yue; Stone, Patricia W
2012-01-01
Staffing measures for RNs, licensed practical nurses (LPN),substitution effect of LPNs for RNs. We defined the staffingsubstitution of LPNs for RNs (Tables 5 and 6). We also found
2011 Annual Workforce Analysis and Staffing Plan Report- Idaho Operations Office
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2012 Annual Workforce Analysis and Staffing Plan Report- Idaho Operations Office
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2012 Annual Workforce Analysis and Staffing Plan Report- West Valley Demonstration Project
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2012 Annual Workforce Analysis and Staffing Plan Report- NNSA Production Office
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2014 Annual Workforce Analysis and Staffing Plan Report- NNSA Production Office
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2012 Annual Workforce Analysis and Staffing Plan Report- Savannah River Operations Office
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2014 Annual Workforce Analysis and Staffing Plan Report- Pacific Northwest Site Office
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2010 Annual Workforce Analysis and Staffing Plan Report- Office of River Protection
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2013 Annual Workforce Analysis and Staffing Plan Report- Office of Health, Safety and Security
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2012 Annual Workforce Analysis and Staffing Plan Report- Nuclear Energy Oak Ridge Site Office
Office of Energy Efficiency and Renewable Energy (EERE)
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2013 Annual Workforce Analysis and Staffing Plan Report- Savannah River Field Office
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2013 Annual Workforce Analysis and Staffing Plan Report- Sandia Field Office
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
2013 Annual Workforce Analysis and Staffing Plan Report- Savannah River Operations Office
Broader source: Energy.gov [DOE]
Managers perform an annual workforce analysis of their organization and develop staffing plans that identify technical capabilities and positions they need to ensure safe operation of defense nuclear facilities.
Chuan, Toh Kim
for the Degree of Doctor of Philosophy by Kim Chuan Toh August 1996 c fl Kim Chuan Toh 1996 ALL RIGHTS RESERVED #12; MATRIX APPROXIMATION PROBLEMS AND NONSYMMETRIC ITERATIVE METHODS Kim Chuan Toh, Ph.D. Cornell
Matrajt, Graciela
University of Washington | Human Resources | UTemp Staffing Program REFERENCE CHECKING CONSENT of Washington and have provided information about my previous employment. I authorize the University of Washington to conduct a reference check with my present and/or previous employer(s). I understand
Multivariate approximation Robert Schaback
Schaback, Robert
Multivariate approximation Robert Schaback July 30, 2013 1 Synonyms Approximation by functions Approximations of functions are multivariate, if they replace functions of n 2 variables defined on a domain. 4 Overview Multivariate approximation is an extension of Approximation Theory and Approximation
Fast Approximate Convex Decomposition
Ghosh, Mukulika
2012-10-19
Approximate convex decomposition (ACD) is a technique that partitions an input object into "approximately convex" components. Decomposition into approximately convex pieces is both more efficient to compute than exact ...
Approximate Information Theory
Penny, Will
Approximate Inference Will Penny Information Theory Information Entropy Kullback-Liebler Divergence Approximate Inference Will Penny 31st March 2011 #12;Approximate Inference Will Penny Information Theory Will Penny Information Theory Information Entropy Kullback-Liebler Divergence Gaussians Asymmetry
Wogman, Ned A.; Bond, Leonard J.; Waltar, Alan E.; Leber, R E.
2005-01-01
The United States, the Department of Energy (DOE) and its National Laboratories, including the Pacific Northwest National Laboratory (PNNL), are facing a serious attrition of nuclear scientists and engineers and their capabilities through the effects of aging staff. Within the DOE laboratories, 75% of nuclear personnel will be eligible to retire by 2010. It is expected that there will be a significant loss of senior nuclear science and technology staff at PNNL within five years. PNNL's nuclear legacy is firmly rooted in the DOE Hanford site, the World War II Manhattan Project, and subsequent programs. Historically, PNNL was a laboratory were 70% of its activities were nuclear/radiological, and now just under 50% of its current business science and technology are nuclear and radiologically oriented. Programs in the areas of Nuclear Legacies, Global Security, Nonproliferation, Homeland Security and National Defense, Radiobiology and Nuclear Energy still involve more than 1,000 of the 3,800 current laboratory staff, and these include more than 420 staff who are certified as nuclear/radiological scientists and engineers. This paper presents the current challenges faced by PNNL that require an emerging strategy to solve the nuclear staffing issues through the maintenance and replenishment of the human nuclear capital needed to support PNNL nuclear science and technology programs.
Wogman, Ned A.; Bond, Leonard J.; Waltar, Alan E.; Leber, R. E.
2005-01-01
The United States, the Department of Energy (DOE) and its National Laboratories, including the Pacific Northwest National Laboratory (PNNL), are facing a serious attrition of nuclear scientists and engineers and their capabilities through the effects of aging staff. Within the DOE laboratories, 75% of nuclear personnel will be eligible to retire by 2010. It is expected that there will be a significant loss of senior nuclear science and technology staff at PNNL within five years. PNNL's nuclear legacy is firmly rooted in the DOE Hanford site, the World War II Manhattan Project, and subsequent programs. Historically, PNNL was a laboratory where 70% of its activities were nuclear/radiological, and now just under 50% of its current business science and technology are nuclear and radiologically oriented. Programs in the areas of Nuclear Legacies, Global Security, Nonproliferation, Homeland Security and National Defense, Radiobiology and Nuclear Energy still involve more than 1,000 of the 3,800 current laboratory staff, and these include more than 420 staff who are certified as nuclear/radiological scientists and engineers. This paper presents the current challenges faced by PNNL that require an emerging strategy to solve the nuclear staffing issues through the maintenance and replenishment of the human nuclear capital needed to support PNNL nuclear science and technology programs.
Approximations non-recursively
Ábrahám, Erika
) * x Regard non-recursively de#12;ned approximations fact 0 = nx -> bot fact 1 = nx -> if x else fact 0 (x 1) #3; x fact 2 = nx -> if x fact of fact should satisfy the de#12;ning equation fact = nx -> if x
Approximation Algorithms for Covering Problems
Koufogiannakis, Christos
2009-01-01
1.3.1 Sequential Algorithms . . . . . . . . . . . . .Distributed 2-approximation algorithm for CMIP 2 (Alg.2 Sequential Algorithm 2.1 The Greedy Algorithm for Monotone
Approximate circuits for increased reliability
Hamlet, Jason R.; Mayo, Jackson R.
2015-12-22
Embodiments of the invention describe a Boolean circuit having a voter circuit and a plurality of approximate circuits each based, at least in part, on a reference circuit. The approximate circuits are each to generate one or more output signals based on values of received input signals. The voter circuit is to receive the one or more output signals generated by each of the approximate circuits, and is to output one or more signals corresponding to a majority value of the received signals. At least some of the approximate circuits are to generate an output value different than the reference circuit for one or more input signal values; however, for each possible input signal value, the majority values of the one or more output signals generated by the approximate circuits and received by the voter circuit correspond to output signal result values of the reference circuit.
Approximate Graph Products Marc Hellmutha
Stadler, Peter F.
Approximate Graph Products Marc Hellmutha , Wilfried Imrichb , Werner Klocklb , Peter F. Stadlera or fingers) can vary independently of other traits, or Email addresses: marc@bioinf.uni-leipzig.de (Marc
APPROXIMATELY UNITARILY EQUIVALENT MORPHISMS AND ...
2010-07-28
?(a) = diag(a(x)1,...,a(xk)), then we say that ? and ? are approximately unitarily ... Mr?1(C(X)) and a unital ?-homomorphism : C(X) ? Mr(C(X)) with finite.
Planning numerical approximations Richard Power
Williams, Sandra
Planning numerical approximations Richard Power Sandra Williams 21st September 2009 #12;Table proportions (e.g., more than a quarter, 25.9 per cent) Proportions are a convenient well-defined subproblem Common in factual discourse (e.g., newspaper articles) Important for generating from data (but neglected
Linear Value Function Approximation Linear Models
Parr, Ronald
Linear Value Function Approximation and Linear Models Ronald Parr Duke University Joint work terminology · Various forms of linear value function approximation · Linear approximate model formulation #12;Outline · Introduce terminology · Various forms of linear value function approximation · Linear
LUBRICATION APPROXIMATION WITH PRESCRIBED NONZERO CONTACT ANGLE
Otto, Felix
LUBRICATION APPROXIMATION WITH PRESCRIBED NONZERO CONTACT ANGLE Felix Otto Department--time existence for a weak solution s(t; x) ?? 0 of the lubrication approximation @ t s + @ x (s @ 3 x s) = 0 in fs will later motivate the way we construct approximate solutions for the lubrication approximation we are going
An approximation technique for jet impingement flow
Najafi, Mahmoud; Fincher, Donald; Rahni, Taeibi; Javadi, KH.; Massah, H.
2015-03-10
The analytical approximate solution of a non-linear jet impingement flow model will be demonstrated. We will show that this is an improvement over the series approximation obtained via the Adomian decomposition method, which is itself, a powerful method for analysing non-linear differential equations. The results of these approximations will be compared to the Runge-Kutta approximation in order to demonstrate their validity.
Low rank approximations of matrices and tensors
Friedland, Shmuel
Low rank approximations of matrices and tensors S. Friedland, V. Mehrmann, A. Miedlar and M, 2008 S. Friedland, V. Mehrmann, A. Miedlar and M. Nkengla Low rank approximations of matrices and tensors #12;Overview S. Friedland, V. Mehrmann, A. Miedlar and M. Nkengla Low rank approximations
Near approximations via general ordered topological spaces
M. Abo-Elhamayel
2014-12-27
Rough set theory is a new mathematical approach to imperfect knowledge. The notion of rough sets is generalized by using an arbitrary binary relation on attribute values in information systems, instead of the trivial equality relation. The topology induced by binary relations is used to generalize the basic rough set concepts. This paper studies near approximation via general ordered topological approximation spaces which may be viewed as a generalization of the study of near approximation from the topological view. The basic concepts of some increasing (decreasing) near approximations, increasing (decreasing) near boundary regions and increasing (decreasing) near accuracy were introduced and sufficiently illustrated. Moreover, proved results, implications and add examples.
APPROXIMATION OF ELECTROMAGNETIC FIELDS: PART I ...
2003-08-06
Oprateurs, 1984, Commissariat `a l'Energie Atomique, Masson, Paris. [10] J. DOUGLAS, JR., J. E. SANTOS, AND D. SHEEN, Approximation of scalar waves in...
Lower bounds for approximate factorizations via semidefinite ...
ABSTRACT The problem of approximately factoring a real or complex multivariate polynomial f seeks minimal perturbations ? f to the coefficients of the input...
Optimization Online - Probabilistic optimization via approximate p ...
W. van vAckooij
2015-05-27
May 27, 2015 ... Probabilistic optimization via approximate p-efficient points and bundle methods. W. van vAckooij(wim.van-ackooij ***at*** edf.fr )
Approximations by Orthonormal Mapped Chebyshev Functions for ...
2014-03-12
a School of Mathematical Science, Xiamen University, 361005 Xiamen, China .... suitable mapping can be used to approximate functions on the whole line R (cf.
Approximate Euclidean Ramsey theorems Adrian Dumitrescu
Dumitrescu, Adrian
Approximate Euclidean Ramsey theorems Adrian Dumitrescu October 27, 2010 Abstract According condition is needed in this case. Keywords: Euclidean Ramsey theory, approximate arithmetic progression result of Ramsey from 1930: Theorem 1 (Ramsey [24]). Let p q, and r be positive integers
APPROXIMATE SIMULATION RELATIONS FOR HYBRID SYSTEMS 1
Pappas, George J.
. Pappas Department of Electrical and Systems Engineering University of Pennsylvania Philadelphia, PA been introduced as a powerful tool for the approximation of discrete and continuous systems systems approximation. An example of application in the context of safety verification is shown. Keywords
APPROXIMATION RESULTS FOR REFLECTIONLESS JACOBI MATRICES
Remling, Christian
APPROXIMATION RESULTS FOR REFLECTIONLESS JACOBI MATRICES ALEXEI POLTORATSKI AND CHRISTIAN REMLING Abstract. We study spaces of reflectionless Jacobi matrices. The main theme is the following type of question: Given a reflectionless Jacobi matrix, is it possible to approximate it by other reflection- less
An improved proximity force approximation for electrostatics
C. D. Fosco; F. C. Lombardo; F. D. Mazzitelli
2012-04-23
A quite straightforward approximation for the electrostatic interaction between two perfectly conducting surfaces suggests itself when the distance between them is much smaller than the characteristic lengths associated to their shapes. Indeed, in the so called "proximity force approximation" the electrostatic force is evaluated by first dividing each surface into a set of small flat patches, and then adding up the forces due two opposite pairs, the contribution of which are approximated as due to pairs of parallel planes. This approximation has been widely and successfully applied to different contexts, ranging from nuclear physics to Casimir effect calculations. We present here an improvement on this approximation, based on a derivative expansion for the electrostatic energy contained between the surfaces. The results obtained could be useful to discuss the geometric dependence of the electrostatic force, and also as a convenient benchmark for numerical analyses of the tip-sample electrostatic interaction in atomic force microscopes.
Approximate error conjugation gradient minimization methods
Kallman, Jeffrey S
2013-05-21
In one embodiment, a method includes selecting a subset of rays from a set of all rays to use in an error calculation for a constrained conjugate gradient minimization problem, calculating an approximate error using the subset of rays, and calculating a minimum in a conjugate gradient direction based on the approximate error. In another embodiment, a system includes a processor for executing logic, logic for selecting a subset of rays from a set of all rays to use in an error calculation for a constrained conjugate gradient minimization problem, logic for calculating an approximate error using the subset of rays, and logic for calculating a minimum in a conjugate gradient direction based on the approximate error. In other embodiments, computer program products, methods, and systems are described capable of using approximate error in constrained conjugate gradient minimization problems.
Wave-mechanics and the adhesion approximation
C. J. Short; P. Coles
2006-11-22
The dynamical equations describing the evolution of a self-gravitating fluid of cold dark matter (CDM) can be written in the form of a Schrodinger equation coupled to a Poisson equation describing Newtonian gravity. It has recently been shown that, in the quasi-linear regime, the Schrodinger equation can be reduced to the exactly solvable free-particle Schrodinger equation. The free-particle Schrodinger equation forms the basis of a new approximation scheme -the free-particle approximation - that is capable of evolving cosmological density perturbations into the quasi-linear regime. The free-particle approximation is essentially an alternative to the adhesion model in which the artificial viscosity term in Burgers' equation is replaced by a non-linear term known as the quantum pressure. Simple one-dimensional tests of the free-particle method have yielded encouraging results. In this paper we comprehensively test the free-particle approximation in a more cosmologically relevant scenario by appealing to an N-body simulation. We compare our results with those obtained from two established methods: the linearized fluid approach and the Zeldovich approximation. We find that the free-particle approximation comprehensively out-performs both of these approximation schemes in all tests carried out and thus provides another useful analytical tool for studying structure formation on cosmological scales.
Ayako Yoshisato; Takahiko Matsubara; Masahiro Morikawa
1997-08-11
Among various analytic approximations for the growth of density fluctuations in the expanding Universe, Zel'dovich approximation and its extensions in Lagrangian scheme are known to be accurate even in mildly non-linear regime. The aim of this paper is to investigate the reason why these Zel'dovich-type approximations work accurately beyond the linear regime from the following two points of view: (1) Dimensionality of the system and (2) the Lagrangian scheme on which the Zel'dovich approximation is grounded. In order to examine the dimensionality, we introduce a model with spheroidal mass distribution. In order to examine the Lagrangian scheme, we introduce the Pad\\'e approximation in Eulerian scheme. We clarify which of these aspects supports the unusual accuracy of the Zel'dovich-type approximations. We also give an implication for more accurate approximation method beyond the Zel'dovich-type approximations.
Harmonic Wavelet Transform and Image Approximation
Zhang, Zhihua; Saito, Naoki
2010-01-01
DOI 10.1007/s10851-010-0202-x Harmonic Wavelet Transform andwe approximate f by a harmonic function u such that thebanks. We call this the Harmonic Wavelet Transform (HWT).
Approximate inference in Gaussian graphical models
Malioutov, Dmitry M., 1981-
2008-01-01
The focus of this thesis is approximate inference in Gaussian graphical models. A graphical model is a family of probability distributions in which the structure of interactions among the random variables is captured by a ...
A fresh look at the adhesion approximation
Thomas Buchert
1997-11-04
I report on a systematic derivation of the phenomenological ``adhesion approximation'' from gravitational instability together with a brief evaluation of the related status of analytical modeling of large-scale structure.
Energy-efficient approximate computation in Topaz
Achour, Sara
2015-01-01
The increasing prominence of energy consumption as a first-order concern in contemporary computing systems has motivated the design of energy-efficient approximate computing platforms. These computing platforms feature ...
Updated: June 21, 2010 Diophantine approximation,
Waldschmidt, Michel
Updated: June 21, 2010 Diophantine approximation, irrationality and transcendence Michel] Chap. 3. See also [1] Chap. III. References [1] S. Lang, Introduction to transcendental numbers transcendants, Springer-Verlag, Berlin, 1974. Lecture Notes in Mathematics, Vol. 402. http
Optimization in Geometric Graphs: Complexity and Approximation
Kahruman-Anderoglu, Sera
2011-02-22
We consider several related problems arising in geometric graphs. In particular, we investigate the computational complexity and approximability properties of several optimization problems in unit ball graphs and develop ...
Signal approximation using the bilinear transform
Venkataraman, Archana, Ph. D. Massachusetts Institute of Technology
2007-01-01
This thesis explores the approximation properties of a unique basis expansion. The expansion implements a nonlinear frequency warping between a continuous-time signal and its discrete-time representation according to the ...
Polymer state approximations of Schroedinger wave functions
Klaus Fredenhagen; Felix Reszewski
2006-08-25
It is shown how states of a quantum mechanical particle in the Schroedinger representation can be approximated by states in the so-called polymer representation. The result may shed some light on the semiclassical limit of loop quantum gravity.
An improved proximity force approximation for electrostatics
Fosco, Cesar D.; Instituto Balseiro, Universidad Nacional de Cuyo, R8402AGP Bariloche ; Lombardo, Fernando C.; IFIBA ; Mazzitelli, Francisco D.
2012-08-15
A quite straightforward approximation for the electrostatic interaction between two perfectly conducting surfaces suggests itself when the distance between them is much smaller than the characteristic lengths associated with their shapes. Indeed, in the so called 'proximity force approximation' the electrostatic force is evaluated by first dividing each surface into a set of small flat patches, and then adding up the forces due two opposite pairs, the contributions of which are approximated as due to pairs of parallel planes. This approximation has been widely and successfully applied in different contexts, ranging from nuclear physics to Casimir effect calculations. We present here an improvement on this approximation, based on a derivative expansion for the electrostatic energy contained between the surfaces. The results obtained could be useful for discussing the geometric dependence of the electrostatic force, and also as a convenient benchmark for numerical analyses of the tip-sample electrostatic interaction in atomic force microscopes. - Highlights: Black-Right-Pointing-Pointer The proximity force approximation (PFA) has been widely used in different areas. Black-Right-Pointing-Pointer The PFA can be improved using a derivative expansion in the shape of the surfaces. Black-Right-Pointing-Pointer We use the improved PFA to compute electrostatic forces between conductors. Black-Right-Pointing-Pointer The results can be used as an analytic benchmark for numerical calculations in AFM. Black-Right-Pointing-Pointer Insight is provided for people who use the PFA to compute nuclear and Casimir forces.
Staffing Guide for Project Management
Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]
2010-06-03
This Guide provides an approach to determining the appropriate level and type of federal personnel needed to effectively plan, direct, and oversee project execution. Admin Chg 1, dated 10-12-11, cancels DOE G 413.3-19.
Extending the Eikonal Approximation to Low Energy
Pierre Capel; Tokuro Fukui; Kazuyuki Ogata
2014-11-21
E-CDCC and DEA, two eikonal-based reaction models are compared to CDCC at low energy (e.g. 20AMeV) to study their behaviour in the regime at which the eikonal approximation is supposed to fail. We confirm that these models lack the Coulomb deflection of the projectile by the target. We show that a hybrid model, built on the CDCC framework at low angular momenta and the eikonal approximation at larger angular momenta gives a perfect agreement with CDCC. An empirical shift in impact parameter can also be used reliably to simulate this missing Coulomb deflection.
Approximating European Options by Rebate Barrier Options
Song, Qingshuo
2011-01-01
When the underlying stock price is a strict local martingale process under an equivalent local martingale measure, Black-Scholes PDE associated with an European option may have multiple solutions. In this paper, we study an approximation for the smallest hedging price of such an European option. Our results show that a class of rebate barrier options can be used for this approximation, when its rebate and barrier are chosen appropriately. An asymptotic convergence rate is also achieved when the knocked-out barrier moves to infinity under suitable conditions.
Exact and Approximate REML for Heteroscedastic Regression
Smyth, Gordon K.
Exact and Approximate REML for Heteroscedastic Regression Gordon K. Smyth Department of Mathematics, the above het- eroscedastic regression model is the most general model of the type considered by LN98 and SV to estimate the het- eroscedastic regression model by way of two coupled generalized linear models
Semicirculant approximations in preconditioners for incompressible flow
be successfully used as an approximate solver of a convectiondiffusion problem in the BFB T preconditioner ([1 of the convection diffusion problem in the BFB T preconditioner for the incompressible Navier Stokes equations of discrete pressures. The square matrix F here is a discrete convectiondiffusion operator. The BFB
The Observer Algorithm for Visibility Approximation
Doherty, Patrick
, with dif- ferent view ranges and grid cell sizes. By changing the size of the grid cells that the algorithm or more sentries while moving to a goal position. Algorithms for finding a covert paths in the presence of stationary and moving sentries has been devised by [5] [6]. An approximate visibility algorithm was devised
Approximate Inference and Protein-Folding
Weiss, Yair
Approximate Inference and Protein-Folding Chen Yanover and Yair Weiss School of Computer Science Side-chain prediction is an important subtask in the protein-folding problem. We show that #12;nding algorithms, including a widely used protein-folding software (SCWRL). 1 Introduction Inference in graphical
Notion of p-value Parametric Approximations
Nuel, Gregory
Notion of p-value Parametric Approximations Power Significance of an Observation in Post-Genomics G, March 7 - 10, 2011 G. NUEL Significance of an Observation in Post-Genomics #12;Notion of p Power of a test ROC and AUC Example with GWAS G. NUEL Significance of an Observation in Post-Genomics
Stochastic Approximation: Sturen in een veranderende wereld
Bhulai, Sandjai
gedaan door middel van simulaties of experimenten. Twee bekende algoritmes binnen Stochastic Approximation zijn het Robbins- Monro algoritme en het Kiefer-Wolfowitz algoritme. Deze algoritmes benaderen formule is de kleine rekentijd en het gebruik van beperkte geheugenruimte. Echter, het algoritme hangt af
Approximations to the Distributed Activation Energy Model
Approximations to the Distributed Activation Energy Model for Pyrolysis C.P. Please, 1 M.J. Mc, then resubmitted after minor revisions in September 2002. Abstract The Distributed Activation Energy Model (DAEM effective method for estimating kinetic parameters and the distribution of activation energies. Comparison
Updated: May 28, 2010 Diophantine approximation,
Waldschmidt, Michel
Updated: May 28, 2010 Diophantine approximation, irrationality and transcendence Michel Waldschmidt [3] is: Theorem 121 (Lambert, 1761). For any r Q \\ {0}, the numbers tan r and er are irrational. In particular the number is irrational. The main tool is continued fractions, and the first goal of Lambert
Updated: June 16, 2010 Diophantine approximation,
Waldschmidt, Michel
Updated: June 16, 2010 Diophantine approximation, irrationality and transcendence Michel. It is known (see for instance [31] p. 25) that if k is a positive integer, if an irrational real number has, 31, 13, 1]. Definition Given a real irrational number , a function = N R>0 is an irrationality
Updated: May 16, 2010 Diophantine approximation,
Waldschmidt, Michel
Updated: May 16, 2010 Diophantine approximation, irrationality and transcendence Michel Waldschmidt of 2 We first give a geometrical proof of the irrationality of the number 2 = 1, 414 213 562 373 095 rectangle. This proves the irrationality of 2. In algebraic terms, the number x = 1 + 2 satisfies x = 2
Updated: June 1, 2010 Diophantine approximation,
Waldschmidt, Michel
Updated: June 1, 2010 Diophantine approximation, irrationality and transcendence Michel Waldschmidt on the irrationality of er when r is a non-zero rational number. Next we show how a slight modification implies.1.1 Irrationality of er for r Q If r = a/b is a rational number such that er is also rational, then e|a| is also
Updated: June 23, 2010 Diophantine approximation,
Waldschmidt, Michel
Updated: June 23, 2010 Diophantine approximation, irrationality and transcendence Michel://www.math.jussieu.fr/ miw/articles/ps/eccm.ps [5] -- , Elliptic functions and transcendence, in Surveys in number theory of and . Schneider's Theorem on the transcendence of j() (corollary 174). 11 Algebraic independence 11.1 Chudnovskii
Second derivatives for approximate spin projection methods
Thompson, Lee M.; Hratchian, Hrant P.
2015-02-07
The use of broken-symmetry electronic structure methods is required in order to obtain correct behavior of electronically strained open-shell systems, such as transition states, biradicals, and transition metals. This approach often has issues with spin contamination, which can lead to significant errors in predicted energies, geometries, and properties. Approximate projection schemes are able to correct for spin contamination and can often yield improved results. To fully make use of these methods and to carry out exploration of the potential energy surface, it is desirable to develop an efficient second energy derivative theory. In this paper, we formulate the analytical second derivatives for the Yamaguchi approximate projection scheme, building on recent work that has yielded an efficient implementation of the analytical first derivatives.
Pulse design without rotating wave approximation
S. Ibez; Yi-Chao Li; Xi Chen; J. G. Muga
2015-10-21
We design realizable time-dependent semiclassical pulses to invert the population of a two-level system faster than adiabatically when the rotating-wave approximation cannot be applied. Different approaches, based on the counterdiabatic method or on invariants, may lead to singularities in the pulse functions. Ways to avoid or cancel the singularities are put forward when the pulse spans few oscillations. For many oscillations an alternative numerical minimization method is proposed and demonstrated.
Approximate convex decomposition and its applications
Lien, Jyh-Ming
2009-05-15
Approved by: Chair of Committee, Nancy M. Amato Committee Members, Ergun Akleman Ricardo Gutierrez-Osuna Donald H. House John C. Keyser Head of Department, Valerie E. Taylor December 2006 Major Subject: Computer Science iii ABSTRACT Approximate Convex...-Yen Li, for teaching me about research. I would like to thank my committee members, John Keyser, Donald House, Ergun Akleman, and Ricardo Gutierrez-Osuna, who supported me through this challenging journey. I would like to thank everyone in the Algorithms...
Semiclassical approximation in Batalin-Vilkovisky formalism
Albert Schwarz
1992-10-23
The geometry of supermanifolds provided with $Q$-structure (i.e. with odd vector field $Q$ satisfying $\\{ Q,Q\\} =0$), $P$-structure (odd symplectic structure ) and $S$-structure (volume element) or with various combinations of these structures is studied. The results are applied to the analysis of Batalin-Vilkovisky approach to the quantization of gauge theories. In particular the semiclassical approximation in this approach is expressed in terms of Reidemeister torsion.
WKB Approximation to the Power Wall
F. D. Mera; S. A. Fulling; J. D. Bouas; K. Thapa
2013-03-28
We present a semiclassical analysis of the quantum propagator of a particle confined on one side by a steeply, monotonically rising potential. The models studied in detail have potentials proportional to $x^{\\alpha}$ for $x>0$; the limit $\\alpha\\to\\infty$ would reproduce a perfectly reflecting boundary, but at present we concentrate on the cases $\\alpha =1$ and 2, for which exact solutions in terms of well known functions are available for comparison. We classify the classical paths in this system by their qualitative nature and calculate the contributions of the various classes to the leading-order semiclassical approximation: For each classical path we find the action $S$, the amplitude function $A$ and the Laplacian of $A$. (The Laplacian is of interest because it gives an estimate of the error in the approximation and is needed for computing higher-order approximations.) The resulting semiclassical propagator can be used to rewrite the exact problem as a Volterra integral equation, whose formal solution by iteration (Neumann series) is a semiclassical, not perturbative, expansion. We thereby test, in the context of a concrete problem, the validity of the two technical hypotheses in a previous proof of the convergence of such a Neumann series in the more abstract setting of an arbitrary smooth potential. Not surprisingly, we find that the hypotheses are violated when caustics develop in the classical dynamics; this opens up the interesting future project of extending the methods to momentum space.
Nonlinear adaptive control using radial basis function approximants
Petersen, Jerry Lee
1993-01-01
The purpose of this research is to present an adaptive control strategy using the radial basis function approximation method. Surface approximation methods using radial basis function approximants will first be discussed. ...
Sensitivity approximation for robust stability and tracking
McLean, Chris Steven
1984-01-01
) Norman W. Na gle (Member) Don R. Halverson (Member) William B. Jones (Head of Department) May 1984 1n Abstract Sensitivity Approximation for Robust Stability and Tracking. (May 1984) Chris Steven McLean, B. S, , Louisiana Tech University... indispensable to the completion of this thesis. I would like to thank Dr. S. P. Bhattacharyya for introducing me to the wonders of automatic control. I also would like to thank Dr. D. R. Halverson and Dr. N. W. Naugle for serving on my committee, Dr. John...
Relativistic Random Phase Approximation At Finite Temperature
Niu, Y. F.; Paar, N.; Vretenar, D.; Meng, J.
2009-08-26
The fully self-consistent finite temperature relativistic random phase approximation (FTRRPA) has been established in the single-nucleon basis of the temperature dependent Dirac-Hartree model (FTDH) based on effective Lagrangian with density dependent meson-nucleon couplings. Illustrative calculations in the FTRRPA framework show the evolution of multipole responses of {sup 132}Sn with temperature. With increased temperature, in both monopole and dipole strength distributions additional transitions appear in the low energy region due to the new opened particle-particle and hole-hole transition channels.
The Background Field Approximation in (quantum) cosmology
R. Parentani
1998-03-12
We analyze the Hamilton-Jacobi action of gravity and matter in the limit where gravity is treated at the background field approximation. The motivation is to clarify when and how the solutions of the Wheeler-DeWitt equation lead to the Schr\\"odinger equation in a given background. To this end, we determine when and how the total action, solution of the constraint equations of General Relativity, leads to the HJ action for matter in a given background. This is achieved by comparing two neighboring solutions differing slightly in their matter energy content. To first order in the change of the 3-geometries, the change of the gravitational action equals the integral of the matter energy evaluated in the background geometry. Higher order terms are governed by the ``susceptibility'' of the geometry. These classical properties also apply to quantum cosmology since the conditions which legitimize the use of WKB gravitational waves are concomitant with those governing the validity of the background field approximation.
The validity of the Background Field Approximation
R. Parentani
1997-10-10
In the absence of a tractable theory of quantum gravity, quantum matter field effects have been so far computed by treating gravity at the Background Field Approximation. The principle aim of this paper is to investigate the validity of this approximation which is not specific to gravity. To this end, for reasons of simplicity and clarity, we shall compare the descriptions of thermal processes induced by constant acceleration (i.e. the Unruh effect) in four dynamical frameworks. In this problem, the position of the ``heavy'' accelerated system plays the role of gravity. In the first framework, the trajectory is treated at the BFA: it is given from the outset and unaffected by radiative processes. In the second one, recoil effects induced by these emission processes are taken into account by describing the system's position by WKB wave functions. In the third one, the accelerated system is described by second quantized fields and in the fourth one, gravity is turned on. It is most interesting to see when and why transitions amplitudes evaluated in different frameworks but describing the same process do agree. It is indeed this comparison that determines the validity of the BFA. It is also interesting to notice that the abandonment of the BFA delivers new physical insights concerning the processes. For instance, in the fourth framework, the ``recoils'' of gravity show that the acceleration horizon area acts as an entropy in delivering heat to accelerated systems.
The local potential approximation in quantum gravity
Dario Benedetti; Francesco Caravelli
2012-10-09
Within the context of the functional renormalization group flow of gravity, we suggest that a generic f(R) ansatz (i.e. not truncated to any specific form, polynomial or not) for the effective action plays a role analogous to the local potential approximation (LPA) in scalar field theory. In the same spirit of the LPA, we derive and study an ordinary differential equation for f(R) to be satisfied by a fixed point of the renormalization group flow. As a first step in trying to assess the existence of global solutions (i.e. true fixed point) for such equation, we investigate here the properties of its solutions by a comparison of various series expansions and numerical integrations. In particular, we study the analyticity conditions required because of the presence of fixed singularities in the equation, and we develop an expansion of the solutions for large R up to order N=29. Studying the convergence of the fixed points of the truncated solutions with respect to N, we find a characteristic pattern for the location of the fixed points in the complex plane, with one point stemming out for its stability. Finally, we establish that if a non-Gaussian fixed point exists within the full f(R) approximation, it corresponds to an R^2 theory.
Recycling Authorizations: Toward Secondary and Approximate Authorizations Model
of matching best suitable approximate authorizations. 1 Introduction Although, every authorization decision
Bethe free energy, Kikuchi approximations and belief propagation
Bethe free energy, Kikuchi approximations and belief propagation algorithms Jonathan S. Yedidia to a stationary point of an approximate free energy, known as the Bethe free energy in statis- tical physics- curate free energy approximations, of which Bethe's approximation is the simplest. Exploiting
Approximate Stokes Drift Profiles in Deep Water
Breivik, yvind; Bidlot, Jean-Raymond
2014-01-01
A deep-water approximation to the Stokes drift velocity profile is explored as an alternative to the monochromatic profile. The alternative profile investigated relies on the same two quantities required for the monochromatic profile, viz the Stokes transport and the surface Stokes drift velocity. Comparisons with parametric spectra and profiles under wave spectra from the ERA-Interim reanalysis and buoy observations reveal much better agreement than the monochromatic profile even for complex sea states. That the profile gives a closer match and a more correct shear has implications for ocean circulation models since the Coriolis-Stokes force depends on the magnitude and direction of the Stokes drift profile and Langmuir turbulence parameterizations depend sensitively on the shear of the profile. The alternative profile comes at no added numerical cost compared to the monochromatic profile.
On the complexity of approximating a nash equilibrium
Daskalakis, Constantinos
2011-01-01
We show that computing a relative---that is, multiplicative as opposed to additive---approximate Nash equilibrium in two-player games is PPAD-complete, even for constant values of the approximation. Our result is the first ...
Approximations for the rotational excitation of molecules by atoms
Chu, Shih-I; Dalgarno, A.
1975-01-01
The applicability of the effective close?coupling approximation of Rabitz and the centrifugal decoupling approximation of McGuire and Kouri is examined for a system which models the rotational excitation of molecular nitrogen in collisions...
Report on some recent advances in Diophantine approximation
Waldschmidt, Michel
by linear forms · irrationality measures · transcendence criterion · criteria for algebraic inde- pendence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 Rational approximation to a real number . . . . . . . . . . . . . . . . . . . . . . . . 6 1, algebraic and simultaneous approximation to a single number
Guest Editorial Sparse Approximations in Signal and Image Processing
Paris-Sud XI, Universit de
Guest Editorial Sparse Approximations in Signal and Image Processing Sparse approximation to solve many other signal processing problems, including blind source separation, feature extraction techniques to images as well as audio and biomedical signals, new efficient im- plementations of greedy
Bond selective chemistry beyond the adiabatic approximation
Butler, L.J. [Univ. of Chicago, IL (United States)
1993-12-01
One of the most important challenges in chemistry is to develop predictive ability for the branching between energetically allowed chemical reaction pathways. Such predictive capability, coupled with a fundamental understanding of the important molecular interactions, is essential to the development and utilization of new fuels and the design of efficient combustion processes. Existing transition state and exact quantum theories successfully predict the branching between available product channels for systems in which each reaction coordinate can be adequately described by different paths along a single adiabatic potential energy surface. In particular, unimolecular dissociation following thermal, infrared multiphoton, or overtone excitation in the ground state yields a branching between energetically allowed product channels which can be successfully predicted by the application of statistical theories, i.e. the weakest bond breaks. (The predictions are particularly good for competing reactions in which when there is no saddle point along the reaction coordinates, as in simple bond fission reactions.) The predicted lack of bond selectivity results from the assumption of rapid internal vibrational energy redistribution and the implicit use of a single adiabatic Born-Oppenheimer potential energy surface for the reaction. However, the adiabatic approximation is not valid for the reaction of a wide variety of energetic materials and organic fuels; coupling between the electronic states of the reacting species play a a key role in determining the selectivity of the chemical reactions induced. The work described below investigated the central role played by coupling between electronic states in polyatomic molecules in determining the selective branching between energetically allowed fragmentation pathways in two key systems.
Approximation Algorithms for Multi-criteria Traveling Salesman Problems
Al Hanbali, Ahmad
+3-42 +, respectively. Moreover, we design ran- domized approximation algorithms for multi-criteria () -ATSP (ratio 1 2. Therefore, we design randomized approximation schemes for multi-criteria cycle cover problems by showingApproximation Algorithms for Multi-criteria Traveling Salesman Problems Bodo Manthey1 and L
Numerical Approximation of Vortex Density Evolution in a Superconductor.
Styles, Vanessa
Numerical Approximation of Vortex Density Evolution in a Superconductor. C.M. Elliott & V. Styles Abstract A #12;nite volume/element approximation of a mean #12;eld model of superconducting vortices in one approximations of a two-dimensional version of the mean #12;eld model of superconducting vortices considered
Input-ouput approximation for nonlinear structural dynamics
Beaver, Stefanie Rene'
2009-05-15
. Nonlinear Assumed Model with Fixed Rotation Rate . 51 V NONLINEAR INPUT-OUTPUT APPROXIMATION . . . . . . 54 A. Algorithm Overview . . . . . . . . . . . . . . . . . . . . . 54 B. Linear Input-Output Approximation . . . . . . . . . . . . 57 C. Least Squares.... Quadratic Assumed Modes with Higher-Order Terms . 77 ix CHAPTER Page 2. Application of Nonlinear Input-Output Approxi- mation Algorithm . . . . . . . . . . . . . . . . . . . . 81 a. Linear Input-Output Approximation . . . . . . . 82 b. Least Squares...
Technical Note Variational free energy and the Laplace approximation
Daunizeau, Jean
Technical Note Variational free energy and the Laplace approximation Karl Friston,a, Jrmie October 2006 This note derives the variational free energy under the Laplace approximation, with a focus. This is relevant when using the free energy as an approximation to the log-evidence in Bayesian model averaging
Automating approximate Bayesian computation by local linear regression
Thornton, Kevin R
2009-01-01
computation by local linear regression Kevin R Thorntonof ABC based on using a linear regression to approximate theimplements the local linear-regression approach to ABC. The
The Numerical Approximation of Solutions of Partial Differential ...
2009-05-05
i.e., instead of thinking of the approximate solution as being linear between .... Consider the mildly nonlinear two-point boundary problem given by. ?(aux )x + c(
How to Solve Schroedinger Problems by Approximating the Potential Function
Ledoux, Veerle; Van Daele, Marnix
2010-09-30
We give a survey over the efforts in the direction of solving the Schroedinger equation by using piecewise approximations of the potential function. Two types of approximating potentials have been considered in the literature, that is piecewise constant and piecewise linear functions. For polynomials of higher degree the approximating problem is not so easy to integrate analytically. This obstacle can be circumvented by using a perturbative approach to construct the solution of the approximating problem, leading to the so-called piecewise perturbation methods (PPM). We discuss the construction of a PPM in its most convenient form for applications and show that different PPM versions (CPM,LPM) are in fact equivalent.
Approximation Algorithms for the Fault-Tolerant Facility Placement Problem
Yan, Li
2013-01-01
5.2 Algorithm ECHS with Ratio5.3 Algorithm EBGS with RatioFormulation 2.1.3 Approximation Algorithms . 2.1.4 Bifactor
ANALOG QUANTUM NEURON FOR FUNCTIONS APPROXIMATION A. EZHOV; A...
Office of Scientific and Technical Information (OSTI)
FOR FUNCTIONS APPROXIMATION A. EZHOV; A. KHROMOV; G. BERMAN 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; IMPLEMENTATION; NERVE CELLS; WAVEGUIDES We describe a system able...
Approximate Dynamic Programming for Networks: Fluid Models and Constraint Reduction
Veatch, Michael H.
of approximating functions for the differential cost. The first contribution of this paper is identifying new or piece-wise quadratic. Fluid cost has been used to initialize the value iteration algorithm [5Approximate Dynamic Programming for Networks: Fluid Models and Constraint Reduction Michael H
USING THE LINEAR NOISE APPROXIMATION TO CHARACTERIZE MOLECULAR NOISE IN
Ingalls, Brian
USING THE LINEAR NOISE APPROXIMATION TO CHARACTERIZE MOLECULAR NOISE IN REACTION PATHWAYS Matthew Canada N2L 3G1 Abstract The Linear Noise Approximation offers an elegant analytic method to probe the effects of molecular noise on small-scale chemical reaction pathways by expanding the full chemical Master
Motivation and Outline Hatree-Fock Theory and KLI Approximation
Holzwarth, Natalie
Motivation and Outline Hatree-Fock Theory and KLI Approximation Frozen core orbital approximation March 24, 2011 Xiao Xu, N. A. W. Holzwarth PAW + HF & KLI #12;Motivation and Outline Hatree-Fock Theory of HF and KLI Conclusion Outline 1 Motivation of this work: Why? orbital dependent functionals + PAW 2
Transport approximations in partially diffusive media Guillaume Bal
Bal, Guillaume
Transport approximations in partially diffusive media Guillaume Bal Department of Applied Physics concerns the analysis of approximations of transport equations in diffusive media. Firstly, we consider a variational formulation for the first-order transport equation that has the correct diffusive behavior
PROJECT REPORT USING NEURAL NETWORKS FOR APPROXIMATE RADIOSITY FORM FACTOR
Anderson, Charles W.
PROJECT REPORT USING NEURAL NETWORKS FOR APPROXIMATE RADIOSITY FORM FACTOR COMPUTATION Submitted, between each pair of objects within the scene. This project report explores the use of neural networks.3 Approximation with Neural Networks : : : : : : : : : : : : : : : : : : : : : : : 2 1.4 Outline of Project Report
Tighter Bounds for Graph Steiner Tree Approximation Gabriel Robins
Zelikovsky, Alexander
and properties. In Section 3 we present our main algorithm, called k-LCA. The basic approximation result for k-LCA is proved in Section 4. In Sections 5 and 6 we prove an approximation ratio of the k-LCA algorithm in general graphs, and estimate the performance of the Iterated 1-Steiner and k-LCA heuristics in qu
Tutorial, GECCO'05, Washington D.C. Fitness Approximation
Yang, Shengxiang
1 Tutorial, GECCO'05, Washington D.C. Fitness Approximation in Evolutionary Computation Yaochu Jin Honda Research Institute Europe Khaled Rasheed University of Georgia Tutorial, GECCO'05, Washington D expensive fitness evaluations Tutorial, GECCO'05, Washington D.C. Fitness Approximation Methods Problem
The Approximation of Nuclear Contaminant Transport in Porous Media
Douglas Jr., Jim
of a chain of radioactive waste products and to present the results of some typical simulationsThe Approximation of Nuclear Contaminant Transport in Porous Media Jim Douglas, Jr. #3; Chieh;ective and ecient numerical method for approximating the solution of equations that govern the transport
Technical Note Variational free energy and the Laplace approximation
Penny, Will
Technical Note Variational free energy and the Laplace approximation Karl Friston,a, Jrmie the variational free energy under the Laplace approximation, with a focus on accounting for additional model complexity induced by increasing the number of model parameters. This is relevant when using the free energy
Fast Vectorless Power Grid Verification Using an Approximate Inverse Technique
Najm, Farid N.
Fast Vectorless Power Grid Verification Using an Approximate Inverse Technique Nahi H. Abdul Ghani Department of ECE University of Toronto Toronto, Ontario, Canada f.najm@utoronto.ca ABSTRACT Power grid Aids General Terms Performance, Algorithms, Verification Keywords Power grid, voltage drop, approximate
Fresnel approximations for acoustic fields of rectangularly symmetric sources
Mast, T. Douglas
Fresnel approximations for acoustic fields of rectangularly symmetric sources T. Douglas Masta for determining the acoustic fields of rectangularly symmetric, baffled, time-harmonic sources under the Fresnel. The expressions presented are generalized to three different Fresnel approximations that correspond, respectively
Energy Content of Colliding Plane Waves using Approximate Noether Symmetries
M. Sharif; Saira Waheed
2011-09-19
This paper is devoted to study the energy content of colliding plane waves using approximate Noether symmetries. For this purpose, we use approximate Lie symmetry method of Lagrangian for differential equations. We formulate the first-order perturbed Lagrangian for colliding plane electromagnetic and gravitational waves. It is shown that in both cases, there does not exist
Approximate and Multipartite Quantum Correlation (Communication) Zhaohui Wei
Jain, Rahul
classical distributions or bipartite quantum states in the single-shot setting by Zhang (Proc. 3rd Innov that the cost to approximate a bipartite quantum state equals that to approximate its exact purifications, which the latter. We characterize the relationship between them by giving upper and lower bounds. 4
Properties of the Boltzmann equation in the classical approximation
Tanji, Naoto; Epelbaum, Thomas; Gelis, Francois; Wu, Bin
2014-12-30
We study the Boltzmann equation with elastic point-like scalar interactions in two different versions of the the classical approximation. Although solving numerically the Boltzmann equation with the unapproximated collision term poses no problem, this allows one to study the effect of the ultraviolet cutoff in these approximations. This cutoff dependence in the classical approximations of the Boltzmann equation is closely related to the non-renormalizability of the classical statistical approximation of the underlying quantum field theory. The kinetic theory setup that we consider here allows one to study in a much simpler way the dependence on the ultraviolet cutoff, since one has also access to the non-approximated result for comparison.
Properties of the Boltzmann equation in the classical approximation
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Epelbaum, Thomas; Gelis, Franois; Tanji, Naoto; Wu, Bin
2014-12-30
We examine the Boltzmann equation with elastic point-like scalar interactions in two different versions of the the classical approximation. Although solving numerically the Boltzmann equation with the unapproximated collision term poses no problem, this allows one to study the effect of the ultraviolet cutoff in these approximations. This cutoff dependence in the classical approximations of the Boltzmann equation is closely related to the non-renormalizability of the classical statistical approximation of the underlying quantum field theory. The kinetic theory setup that we consider here allows one to study in a much simpler way the dependence on the ultraviolet cutoff, since onemorehas also access to the non-approximated result for comparison.less
Higher-degree linear approximations of nonlinear systems
Karahan, S.
1989-01-01
In this dissertation, the author develops a new method for obtaining higher degree linear approximations of nonlinear control systems. The standard approach in the analysis and synthesis of nonlinear systems is a first order approximation by a linear model. This is usually performed by obtaining a series expansion of the system at some nominal operating point and retaining only the first degree terms in the series. The accuracy of this approximation depends on how far the system moves away from the normal point, and on the relative magnitudes of the higher degree terms in the series expansion. The approximation is achieved by finding an appropriate nonlinear coordinate transformation-feedback pair to perform the higher degree linearization. With the proposed method, one can improve the accuracy of the approximation up to arbitrarily higher degrees, provided certain solvability conditions are satisfied. The Hunt-Su linearizability theorem makes these conditions precise. This approach is similar to Poincare's Normal Form Theorem in formulation, but different in its solution method. After some mathematical background the author derives a set of equations (called the Homological Equations). A solution to this system of linear equations is equivalent to the solution to the problem of approximate linearization. However, it is generally not possible to solve the system of equations exactly. He outlines a method for systematically finding approximate solutions to these equations using singular value decomposition, while minimizing an error with respect to some defined norm.
Improved approximate formulas for flux from cylindrical and rectangular sources
Wallace, O.J.; Bokharee, S.A.
1993-03-01
This report provides two new approximate formulas for the flux at detector points outside the radial and axial extensions of a homogeneous cylindrical source and improved approximate formulas for the flux at points opposite rectangular surface sources. These formulas extend the range of geometries for which analytic approximations may be used by shield design engineers to make rapid scoping studies and check more extensive calculations for reasonableness. These formulas can be used to support skeptical, independent evaluations and are also valuable teaching tools for introducing shield designers to complex shield analyses.
The local potential approximation in the background field formalism
I. Hamzaan Bridle; Juergen A. Dietz; Tim R. Morris
2014-03-20
Working within the familiar local potential approximation, and concentrating on the example of a single scalar field in three dimensions, we show that the commonly used approximation method of identifying the total and background fields, leads to pathologies in the resulting fixed point structure and the associated spaces of eigenoperators. We then show how a consistent treatment of the background field through the corresponding modified shift Ward identity, can cure these pathologies, restoring universality of physical quantities with respect to the choice of dependence on the background field, even within the local potential approximation. Along the way we point out similarities to what has been previously found in the f(R) approximation in asymptotic safety for gravity.
The WKB approximation for a linear potential and ceiling
Zapata, Todd Austin
2009-05-15
The physical problem this thesis deals with is a quantum system with linear potential driving a particle away from a ceiling (impenetrable barrier). This thesis will construct the WKB approximation of the quantum mechanical propagator...
Mean Field Variational Approximations in Continuous-Time Markov Processes
Friedman, Nir
Mean Field Variational Approximations in Continuous-Time Markov Processes A thesis submitted Processes . . . . . . . . . . . . . . . . . . . 18 2.3 Continuous Time Markov Processes-component Representation - Continuous Time Bayesian Networks . 24 2.3.3 Inference in Continuous Time Markov Processes
Numerical Approximations of Stochastic Optimal Stopping and Control Problems
Siska, David
2007-01-01
We study numerical approximations for the payoff function of the stochastic optimal stopping and control problem. It is known that the payoff function of the optimal stopping and control problem corresponds to the solution ...
Approximate translation : media, narrative, and experience in urban design
Crisman, Jonathan
2013-01-01
Approximate translation is developed as a design process through which the place-embedded history of an urban environment can be understood, allowing for better design and intervention in that urban environment. Generally, ...
Tractability through approximation : a study of two discrete optimization problems
Farahat, Amr, 1973-
2004-01-01
(cont.) algorithm, at one extreme, and complete enumeration, at the other extreme. We derive worst-case approximation guarantees on the solution produced by such an algorithm for matroids. We then define a continuous ...
Queueing systems subject to random server failures: an approximation
Matis, Timothy
1998-01-01
research into finding exact or approximate methods that adjust key performance measures of a system to reflect server failures. Many of the methods that have been developed suffer either from a high degree of computational complexity or from tight...
APPROXIMATING SPECTRAL INVARIANTS OF HARPER OPERATORS ON GRAPHS II
Schick, Thomas
APPROXIMATING SPECTRAL INVARIANTS OF HARPER OPERATORS ON GRAPHS II VARGHESE MATHAI, THOMAS SCHICK;2 VARGHESE MATHAI, THOMAS SCHICK, AND STUART YATES subset E+ of these edges in which each combinatorial edge
Approximate dynamic programming with applications in multi-agent systems
Valenti, Mario J. (Mario James), 1976-
2007-01-01
This thesis presents the development and implementation of approximate dynamic programming methods used to manage multi-agent systems. The purpose of this thesis is to develop an architectural framework and theoretical ...
Approximate Description of the Mandelbrot Set. Thermodynamic Analogy
O. B. Isaeva; S. P. Kuznetsov
2005-04-29
Analogy between an approximate version of Feigenbaum renormalization group analysis in complex domain and the phase transition theory of Yang-Lee (based on consideration of formally complexified thermodynamic values) is discussed. It is shown that the Julia sets of the renormalization transformation correspond to the approximation of Mandelbrot set of the original map. New aspects of analogy between the theory of dynamical systems and the phase transition theory are uncovered.
Resonant-state expansion Born Approximation applied to Schrodinger's Equation
Doost, M B
2015-01-01
The RSE Born Approximation is a new scattering formula in Physics, it allows the calculation of strong scattering via the Fourier transform of the scattering potential and Resonant-states. In this paper I apply the RSE Born Approximation to Schr\\"odinger's Equation. The resonant-states of the system can be calculated using the recently discovered RSE perturbation theory and normalised correctly to appear in spectral Green's functions via the flux volume normalisation.
Mean field approximation for noisy delay coupled excitable neurons
Nikola Buric; Dragana Rankovic; Kristina Todorovic; Nebojsa Vasovic
2010-03-26
Mean field approximation of a large collection of FitzHugh-Nagumo excitable neurons with noise and all-to-all coupling with explicit time-delays, modelled by $N\\gg 1$ stochastic delay-differential equations is derived. The resulting approximation contains only two deterministic delay-differential equations but provides excellent predictions concerning the stability and bifurcations of the averaged global variables of the exact large system.
Choosing the Summary Statistics and the Acceptance Rate in Approximate Bayesian
Blum, Michael G. B.
Choosing the Summary Statistics and the Acceptance Rate in Approximate Bayesian Computation or not. In this paper, I incorporate Approximate Bayesian Computation into a local Bayesian regression Computation, evidence approximation, empirical Bayes, Bayesian local regression 1 Introduction Approximate
Federal Staffing Guide for Project Management
Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]
2010-06-03
This Guide provides an approach to determining the appropriate level and type of federal personnel needed to effectively plan, direct, and oversee project execution. Superseded by DOE G 413.3-19 Admin Chg 1.
Workforce Analysis and Staffing | Department of Energy
Office of Environmental Management (EM)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirley Ann Jackson About1996HowFOAShowingFuelWeatherize »EvePlant | Department ofJuly 27,Policy,
Employment and Staffing | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE: Alternative Fuels DataEnergyInformation Form Employee Information Form New
Variational principles with Pad approximants for tearing mode analysis
Cole, Andrew J.; Finn, John M.
2014-03-15
Tearing modes occur in several distinct physical regimes, and it is often important to compute the inner layer response for these modes with various effects. There is a need for an approximate and efficient method of solving the inner layer equations in all these regimes. In this paper, we introduce a method of solving the inner layer equations based on using a variational principle with Pad approximants. For all the regimes considered, the main layer equations to be solved are inhomogeneous, and Pad approximants give a convenient and efficient method of satisfying the correct asymptotic behavior at the edge of the layer. Results using this variational principlePad approximant method in three of these regimes is presented. These regimes are the constant-? resistive-inertial (RI) regime, the constant-? viscoresistive regime, and the non-constant-? inviscid tearing regime. The last regime includes the constant-? RI regime and the inertial regime. The results show that reasonable accuracy can be obtained very efficiently with Pad approximants having a small number of parameters.
Fourth-post-Newtonian-exact approximation to General Relativity
David Brizuela; Gerhard Schaefer
2010-04-12
An approximation to General Relativity is presented that agrees with the Einstein field equations up to and including the fourth post-Newtonian (PN) order. This approximation is formulated in a fully constrained scheme: all involved equations are explicitly elliptic except the wave equation that describes the two independent degrees of freedom of the gravitational field. The formalism covers naturally the conformal-flat-condition (CFC) approach by Isenberg, Wilson, and Mathews and the improved second PN-order exact approach CFC+. For stationary configurations, like Kerr black holes, agreement with General Relativity is achieved even through 5PN order. In addition, a particularly interesting 2PN-exact waveless approximation is analyzed in detail, which results from imposing more restrictive conditions. The proposed scheme can be considered as a further development on the waveless approach suggested by Schaefer and Gopakumar [Phys. Rev. D {\\bf 69}, 021501 (2004)].
Trigonometric Pade approximants for functions with regularly decreasing Fourier coefficients
Labych, Yuliya A; Starovoitov, Alexander P [Gomel State University, Gomel (Belarus)
2009-08-31
Sufficient conditions describing the regular decrease of the coefficients of a Fourier series f(x)=a{sub 0}/2 + {sigma} a{sub n} cos kx are found which ensure that the trigonometric Pade approximants {pi}{sup t}{sub n,m}(x;f) converge to the function f in the uniform norm at a rate which coincides asymptotically with the highest possible one. The results obtained are applied to problems dealing with finding sharp constants for rational approximations. Bibliography: 31 titles.
L^p Bernstein Inequalities and Radial Basis Function Approximation
Ward, John P.
2012-10-19
are bounded in terms of certain measurements of the set X. The error of approximation will typically be given in terms of the ll distance hX = sup x2Rd inf 2X jjx jj2 ; which measures how far a point in Rd can be from X, and the stability of the ap... will typically be restricted to sets X for which hX is comparable to qX , and sets for which the mesh ratio X := hX=qX is bounded by a constant will be called quasi-uniform. In this paper, we will only consider approximation spaces SX( ) where X is quasi...
On the approximation of crack shapes found during inservice inspection
Bhate, S.R.; Chawla, D.S.; Kushwaha, H.S. [Bhabha Atomic Research Centre, Bombay (India)] [and others
1997-04-01
This paper addresses the characterization of axial internal flaw found during inservice inspection of a pipe. J-integral distribution for various flaw shapes is obtained using line spring finite, element method. The peak J-value and its distribution across the crack is found to be characteristic feature of each shape. The triangular shape yields peak J-value away from the center, the point of depth. The elliptic approximation results in large overestimate of J-value for unsymmetric flaws. Triangular approximation is recommended for such flaws so that further service can be obtained from the component.
Approximations of very weak solutions to boundary-value problems.
Berggren, Martin Olof
2003-03-01
Standard weak solutions to the Poisson problem on a bounded domain have square-integrable derivatives, which limits the admissible regularity of inhomogeneous data. The concept of solution may be further weakened in order to define solutions when data is rough, such as for inhomogeneous Dirichlet data that is only square-integrable over the boundary. Such very weak solutions satisfy a nonstandard variational form (u, v) = G(v). A Galerkin approximation combined with an approximation of the right-hand side G defines a finite-element approximation of the very weak solution. Applying conforming linear elements leads to a discrete solution equivalent to the text-book finite-element solution to the Poisson problem in which the boundary data is approximated by L{sub 2}-projections. The L{sub 2} convergence rate of the discrete solution is O(h{sub s}) for some s {element_of} (0,1/2) that depends on the shape of the domain, asserting a polygonal (two-dimensional) or polyhedral (three-dimensional) domain without slits and (only) square-integrable boundary data.
APPROXIMATION OF A TWOPHASE CONTINUOUS CASTING STEFAN PROBLEM
APPROXIMATION OF A TWOPHASE CONTINUOUS CASTING STEFAN PROBLEM Zhiming Chen \\Lambda Lishang Jiang y Abstract. The continuous casting Stefan problem is a mathematical model describing the solidification with convection of a material being cast continuously with a prescribed velocity. We propose a practical piecewise
Accelerating Search of Approximate Match on Large Protein Sequence Databases
Wang, Wei
of supporting indexed search on large biological sequence databases since the construction cost of the index Yang 2 , Yi Xia 3 , Philip Yu 4 Keywords: protein sequence index, approximate match. Due. Building an appropriate index structure is one of the possibilities to achieve such a goal, which
APPROXIMATION THEORY OF OUTPUT STATISTICS Dept. Information Systems
Verd, Sergio
. In order to generate a ran- dom process we assume that a primary random source with an equiprobableAPPROXIMATION THEORY OF OUTPUT STATISTICS Te Sun Han Dept. Information Systems Senshu University-length) source coding rate of any finite-alphabet source, and a strong converse of the identijication coding
Expected Approximation Guarantees for the Demand Matching Problem
Boucher, Christina
Expected Approximation Guarantees for the Demand Matching Problem C. Boucher D. Loker September 2006 Abstract The objective of the demand matching problem is to obtain the subset M of edges which if for each vertex v the total demand of edges in M incident to v is at most bv. In the case where each
Approximability of Partitioning Graphs with Supply and Demand
Demaine, Erik
Approximability of Partitioning Graphs with Supply and Demand Takehiro Ito a,, Erik D. Demaine b vertex or a demand vertex and is assigned a positive real number, called the supply or the demand. Each demand vertex can receive "power" from at most one supply vertex through edges in G. One thus wishes
Approximability of Partitioning Graphs with Supply and Demand
Demaine, Erik
Approximability of Partitioning Graphs with Supply and Demand (Extended Abstract) Takehiro Ito1 vertex or a demand vertex and is assigned a positive real number, called the supply or the demand. Each demand vertex can receive "power" from at most one supply vertex through edges in G. One thus wishes
Approximability of Partitioning Graphs with Supply and Demand
Demaine, Erik
Approximability of Partitioning Graphs with Supply and Demand (Extended Abstract) Takehiro Ito 1 vertex or a demand vertex and is assigned a positive real number, called the supply or the demand. Each demand vertex can receive ``power'' from at most one supply vertex through edges in G. One thus wishes
New approximate radial wave functions for power-law potentials
Vladimir Kudryashov
2007-09-26
Radial wave functions for power-law potentials are approximated with the help of power-law substitution and explicit summation of the leading constituent WKB series. Our approach reproduces the correct behavior of the wave functions at the origin, at the turning points and far away from the turning points
A new shallow approximation for tridimensional non-isothermal viscoplastic
Saramito, Pierre
. The risk assessments for volcanic lava flow pose a difficult challenge to numerical methods. Indeed approximated by an autoadaptive finite element method, based on the Rheolef C++ library, allowing to track with non-isothermal experimental measurements for a silicone oil dome. Next, the December 2010 eruption
A Study of Approximate Data Management Techniques for Sensor Networks
Martin, Ralph R.
the monitoring operation of sensor nodes by efficiently using their limited energy, bandwidth and computation. The network can therefore be treated as a distributed sensor data management system. Sensor networks differA Study of Approximate Data Management Techniques for Sensor Networks Adonis Skordylis, Niki
Approximate bisimulation for a class of stochastic hybrid systems
Pappas, George J.
, target tracking, robotics, and power systems [35]. The field of stochastic hybrid systems is a veryApproximate bisimulation for a class of stochastic hybrid systems (Invited Paper) Agung Julius of stochastic hybrid systems, namely, the jump linear stochastic systems (JLSS). The idea is based
Approximate Minimum-Energy Multicasting in Wireless Ad Hoc Networks
Liang, Weifa
Approximate Minimum-Energy Multicasting in Wireless Ad Hoc Networks Weifa Liang, Senior Member, IEEE Abstract--A wireless ad hoc network consists of mobile nodes that are equipped with energy on energy conservation in wireless ad hoc networks have been conducted. For example, energy efficient
Aqua: A Fast Decision Support System Using Approximate Query Answers
Gibbons, Phillip B.
commercial relational DBMS. Aqua precomputes synopses (special sta- tistical summaries) of the original data and stores them in the DBMS. It provides approximate an- swers (with quality guarantees) by rewriting on top of any SQL- compliant DBMS managing a data warehouse. Aqua pre- computes statistical summaries
Approximating many-body induction to efficiently describe molecular liquids
Herbert, John
on the structure and solvation dynamics of the excess electron (in the ground state) but does have a large impact as the structures and properties of molecular systems. This study focuses on approximating many-body electronic methods in order to allow "on-the-fly" energy and force evaluations in dynamical calculations
Approximating Minimum-Power Degree and Connectivity Problems
Kortsarz, Guy
. The power con- sumption of a station determines its transmission range, and thus also the stations it can. Assigning power levels to the stations (nodes) determines the resulting communi- cation network. ConverselyApproximating Minimum-Power Degree and Connectivity Problems Guy Kortsarz Vahab S. Mirrokni Zeev
Dynamic Adaptive Search Based Software Engineering Needs Fast Approximate Metrics
Harman, Mark
1 Dynamic Adaptive Search Based Software Engineering Needs Fast Approximate Metrics Mark Harman. University College Dublin, Ireland. Abstract--Search Based Software Engineering (SBSE) uses fitness functions to guide an automated search for solutions to challenging software engineering problems. The fitness
Novel approximations for inference and learning in nonlinear dynamical systems
Heskes, Tom
Novel approximations for inference and learning in nonlinear dynamical systems Alexander Ypma #3 from marketing research. 1 Introduction Many real-world systems are nonlinear, dynamical and stochastic in nature. Inference and learning of nonlinear system models with hidden dynamics is a dicult task, which
Exploiting Correlated Keywords to Improve Approximate Information Filtering
Tryfonopoulos, Christos
, Christos Tryfonopoulos, and Gerhard Weikum Databases and Information Systems Department Max-Planck Institut- scribe to information sources and be notified whenever new documents of interest are published. In approximate infor- mation filtering only selected information sources, that are likely to publish documents
Approximating Radon measures on first--countable compact spaces
Plebanek, Grzegorz
Approximating Radon measures on first--countable compact spaces Grzegorz Plebanek (Wroc/law) Abstract The assertion every Radon measure defined on a first--countable compact space is uniformly regular under CH. In this note we consider some properties of finite Radon measures defined on compact spaces
Approximation in Mechanism Design By JASON D. HARTLINE
Hartline, Jason D.
Approximation in Mechanism Design By JASON D. HARTLINE A mechanism gives a mapping between will arise in the equilibrium of selfish agent play. Mechanism design then considers the optimization question of what mechanisms have good outcomes in equilibrium. Optimal mechanism design searches
Gluon Condensate in Pion Superfluid beyond Mean Field Approximation
Yin Jiang; Pengfei Zhuang
2011-03-04
We study gluon condensate in a pion superfluid, through calculating the equation of state of the system in the Nambu-Jona-Lasinio model. While in mean field approximation the growing pion condensate leads to an increasing gluon condensate, meson fluctuations reduce the gluon condensate and the broken scalar symmetry can be smoothly restored at finite isospin density.
Single-frequency approximation of the coupling ray theory
Cerveny, Vlastislav
. Introduction There are two different highfrequency asymptotic ray theories with frequencyindepen- dent) demonstrated analytically that the highfrequency asymptotic error of the In: Seismic Waves in Complex 3DSingle-frequency approximation of the coupling ray theory Ludek Klimes & Petr Bulant Department
Asymptotic Approximations to the Distributed Activation Energy Model
McGuinness, Mark
Asymptotic Approximations to the Distributed Activation Energy Model M.J.McGuinness1 , E. Donskoi2 by a continuum distribution in activation energy of individual re- actions. An individual reaction is characterised by a pre-exponential coefficient and an activation energy. The distribution, usually Gaussian
Continued fractions with low complexity: Transcendence measures and quadratic approximation
Bugeaud, Yann
expansion of an irrational algebraic number either is ultimately periodic (this is the case if, and only if. Theorems 3.2 and 3.3 give transcendence mea- sures for a class of transcendental numbers defined by theiContinued fractions with low complexity: Transcendence measures and quadratic approximation Yann
NUMERICAL APPROXIMATION OF A MACROSCOPIC MODEL OF PEDESTRIAN FLOWS
Chalons, Christophe
NUMERICAL APPROXIMATION OF A MACROSCOPIC MODEL OF PEDESTRIAN FLOWS CHRISTOPHE CHALONS Abstract for the description of the flow of pedestrians. Solutions of the associated Riemann problem are known to be possibly in obtaining an efficient numerical scheme. Numerical evidences are proposed. Key words. macroscopic pedestrian
NON-LINEAR FUNCTIONAL APPROXIMATION OF HETEROGENEOUS DYNAMICS
in a latent variable model designed to account for both switching multi-scaling regimes and cascade system or resolution levels. We aim to design ad hoc approximation instruments dealing with a particularly complex in improving the volatility feature detection power. Then we show the good performance of greedy approxima
CP-networks: semantics, complexity, approximations and extensions
Walsh, Toby
CP-networks: semantics, complexity, approximations and extensions F. Rossi, K. B. Venable Dept Constraint Computation Centre, University College Cork Cork, Ireland tw@4c.ucc.ie July 23, 2002 Abstract CP-networks are an elegant and compact qualitative framework for ex- pressing preferences. Unfortunately, reasoning with CP
Robust Nonparametric Data Approximation of Point Sets via Data Reduction
Durocher, Stephane
, and the cardinality of Q is minimized among all such maximizing subsets of P. Our algorithms have respective running), where k optimizes one or more functions of P, where approximations are used to render vector-based features such as streets, rivers, or coastlines
The Exemplar Breakpoint Distance for nontrivial genomes cannot be approximated
Fertin, Guillaume
The Exemplar Breakpoint Distance for nontrivial genomes cannot be approximated Guillaume Blin 1 France guillaume.fertin@univnantes.fr Abstract. A promising and active field of comparative genomics con sists in comparing two genomes by establishing a onetoone correspon dence (i.e., a matching) between
Approximate Dynamic Programming in Transportation and Logistics: A Unified Framework
Powell, Warren B.
Approximate Dynamic Programming in Transportation and Logistics: A Unified Framework Warren B Engineering Princeton University, Princeton, NJ 08544 European J. of Transportation and Logistics, Vol. 1, No optimization has enjoyed a rich place in transportation and logistics, where it repre- sents a mature field
Benchmarking mean-field approximations to level densities
Y. Alhassid; G. F. Bertsch; C. N. Gilbreth; H. Nakada
2015-12-11
We assess the accuracy of finite-temperature mean-field theory using as a standard the Hamiltonian and model space of the shell model Monte Carlo calculations. Two examples are considered: the nucleus $^{162}$Dy, representing a heavy deformed nucleus, and $^{148}$Sm, representing a nearby heavy spherical nucleus with strong pairing correlations. The errors inherent in the finite-temperature Hartree-Fock and Hartree-Fock-Bogoliubov approximations are analyzed by comparing the entropies of the grand canonical and canonical ensembles, as well as the level density at the neutron resonance threshold, with shell model Monte Carlo (SMMC) calculations, which are accurate up to well-controlled statistical errors. The main weak points in the mean-field treatments are seen to be: (i) the extraction of number-projected densities from the grand canonical ensembles, and (ii) the symmetry breaking by deformation or by the pairing condensate. In the absence of a pairing condensate, we confirm that the usual saddle-point approximation to extract the number-projected densities is not a significant source of error compared to other errors inherent to the mean-field theory. We also present an alternative formulation of the saddle-point approximation that makes direct use of an approximate particle-number projection and avoids computing the usual three-dimensional Jacobian of the saddle-point integration. We find that the pairing condensate is less amenable to approximate particle-number projection methods due to the explicit violation of particle-number conservation in the pairing condensate. Nevertheless, the Hartree-Fock-Bogoliubov theory is accurate to less than one unit of entropy for $^{148}$Sm at the neutron threshold energy, which is above the pairing phase transition.
On the Peterlin approximation for turbulent flows of polymer solutions
Vincenzi, Dario; Biferale, Luca; Toschi, Federico
2015-01-01
We study the impact of the Peterlin approximation on the statistics of the end-to-end separation of poly- mers in a turbulent flow. The FENE and FENE-P models are numerically integrated along a large number of Lagrangian trajectories resulting from a direct numerical simulation of three-dimensional homogeneous isotropic turbulence. Although the FENE-P model yields results in qualitative agreement with those of the FENE model, quantitative differences emerge. The steady-state probability of large extensions is overesti- mated by the FENE-P model. The alignment of polymers with the eigenvectors of the rate-of-strain tensor and with the direction of vorticity is weaker when the Peterlin approximation is used. At large Weissenberg numbers, both the correlation times of the extension and of the orientation of polymers are underestimated by the FENE-P model.
Axially symmetric dissipative fluids in the quasi--static approximation
Herrera, L; Ospino, J; Carot, J
2015-01-01
Using a framework based on the $1+3$ formalism we carry out a study on axially and reflection symmetric dissipative fluids, in the quasi--static regime. We first derive a set of invariantly defined "velocities", which allow for an inambiguous definition of the quasi--static approximation. Next we rewrite all the relevant equations in this aproximation and extract all the possible, physically relevant, consequences ensuing the adoption of such an approximation. In particular we show how the vorticity, the shear and the dissipative flux, may lead to situations where different kind of "velocities" change of sign within the fluid distribution with respect to theirs sign on the boundary surface. It is shown that states of gravitational radiation are not {\\it a priori} incompatible with the quasistatic--regime. However, any such state must last for an infinite period of time, thereby diminishing its physical relevance.
Quasielastic electron-deuteron scattering in the weak binding approximation
Ethier, Jacob J. [William and Mary College, JLAB; Doshi, Nidhi P. [Carnegie Mellon University; Malace, Simona P. [JLAB; Melnitchouk, Wally [JLAB
2014-06-01
We perform a global analysis of all available electron-deuteron quasielastic scattering data using Q^2-dependent smearing functions that describe inclusive inelastic e-d scattering within the weak binding approximation. We study the dependence of the cross sections on the deuteron wave function and the off-shell extrapolation of the elastic electron-nucleon cross section, which show particular sensitivity at x >> 1. The excellent overall agreement with data over a large range of Q^2 and x suggest a limited need for effects beyond the impulse approximation, with the exception of the very high-x or very low-Q^2 regions, where short-distance effects in the deuteron become more relevant.
Feedback stabilisation of switched systems via iterative approximate eigenvector assignment
Haimovich, Hernan
2010-01-01
This paper presents and implements an iterative feedback design algorithm for stabilisation of discrete-time switched systems under arbitrary switching regimes. The algorithm seeks state feedback gains so that the closed-loop switching system admits a common quadratic Lyapunov function (CQLF) and hence is uniformly globally exponentially stable. Although the feedback design problem considered can be solved directly via linear matrix inequalities (LMIs), direct application of LMIs for feedback design does not provide information on closed-loop system structure. In contrast, the feedback matrices computed by the proposed algorithm assign closed-loop structure approximating that required to satisfy Lie-algebraic conditions that guarantee existence of a CQLF. The main contribution of the paper is to provide, for single-input systems, a numerical implementation of the algorithm based on iterative approximate common eigenvector assignment, and to establish cases where such algorithm is guaranteed to succeed. We inc...
On the Peterlin approximation for turbulent flows of polymer solutions
Dario Vincenzi; Prasad Perlekar; Luca Biferale; Federico Toschi
2015-05-26
We study the impact of the Peterlin approximation on the statistics of the end-to-end separation of poly- mers in a turbulent flow. The FENE and FENE-P models are numerically integrated along a large number of Lagrangian trajectories resulting from a direct numerical simulation of three-dimensional homogeneous isotropic turbulence. Although the FENE-P model yields results in qualitative agreement with those of the FENE model, quantitative differences emerge. The steady-state probability of large extensions is overesti- mated by the FENE-P model. The alignment of polymers with the eigenvectors of the rate-of-strain tensor and with the direction of vorticity is weaker when the Peterlin approximation is used. At large Weissenberg numbers, both the correlation times of the extension and of the orientation of polymers are underestimated by the FENE-P model.
Crystallization of polyethylene by modified weighted density approximation(MWDA)
Razeghizadeh, Alireza; Lavafpour, Farhad
2015-01-01
In this article, we use the modified weighted density approximation to study the crystallization of polyethylene. We also use a direct correlation function of polyethylene based on RISM theory. The free energy of a polyethylene is calculated using density functional theory. The crystallization and solid and liquid density are calculated and finally compared with the prism simulation and experimental results. That shown the result obtained by MWDA is in better agreement, compared with the experimental result than the prism.
Crystallization of polyethylene by modified weighted density approximation(MWDA)
Alireza Razeghizadeh; Vahdat Rafee; Farhad Lavafpour
2015-02-07
In this article, we use the modified weighted density approximation to study the crystallization of polyethylene. We also use a direct correlation function of polyethylene based on RISM theory. The free energy of a polyethylene is calculated using density functional theory. The crystallization and solid and liquid density are calculated and finally compared with the prism simulation and experimental results. That shown the result obtained by MWDA is in better agreement, compared with the experimental result than the prism.
Product-state Approximations to Quantum Ground States
Fernando G. S. L. Brando; Aram W. Harrow
2014-12-15
The local Hamiltonian problem consists of estimating the ground-state energy (given by the minimum eigenvalue) of a local quantum Hamiltonian. First, we show the existence of a good product-state approximation for the ground-state energy of 2-local Hamiltonians with one or more of the following properties: (1) high degree, (2) small expansion, or (3) a ground state with sublinear entanglement with respect to some partition into small pieces. The approximation based on degree is a surprising difference between quantum Hamiltonians and classical CSPs (constraint satisfaction problems), since in the classical setting, higher degree is usually associated with harder CSPs. The approximation based on low entanglement, in turn, was previously known only in the regime where the entanglement was close to zero. Since the existence of a low-energy product state can be checked in NP, the result implies that any Hamiltonian used for a quantum PCP theorem should have: (1) constant degree, (2) constant expansion, (3) a "volume law" for entanglement with respect to any partition into small parts. Second, we show that in several cases, good product-state approximations not only exist, but can be found in polynomial time: (1) 2-local Hamiltonians on any planar graph, solving an open problem of Bansal, Bravyi, and Terhal, (2) dense k-local Hamiltonians for any constant k, solving an open problem of Gharibian and Kempe, and (3) 2-local Hamiltonians on graphs with low threshold rank, via a quantum generalization of a recent result of Barak, Raghavendra and Steurer. Our work introduces two new tools which may be of independent interest. First, we prove a new quantum version of the de Finetti theorem which does not require the usual assumption of symmetry. Second, we describe a way to analyze the application of the Lasserre/Parrilo SDP hierarchy to local quantum Hamiltonians.
Denoising MR Spectroscopic Imaging Data with Low-Rank Approximations
Do, Minh N.
1 Denoising MR Spectroscopic Imaging Data with Low-Rank Approximations Hien M. Nguyen, Member, IEEE- temporal imaging data as well. Index Terms--MR spectroscopy, MR spectroscopic imaging, denoising, low spectroscopic (MRS) signal in (k, t)-space can be expressed as s(k, t) = (r, f)e-i2kr e-i2ft drdf + (k, t), (1
COMPLEXITY & APPROXIMABILITY OF QUANTIFIED & STOCHASTIC CONSTRAINT SATISFACTION PROBLEMS
H. B. HUNT; M. V. MARATHE; R. E. STEARNS
2001-06-01
Let D be an arbitrary (not necessarily finite) nonempty set, let C be a finite set of constant symbols denoting arbitrary elements of D, and let S and T be an arbitrary finite set of finite-arity relations on D. We denote the problem of determining the satisfiability of finite conjunctions of relations in S applied to variables (to variables and symbols in C) by SAT(S) (by SATc(S).) Here, we study simultaneously the complexity of decision, counting, maximization and approximate maximization problems, for unquantified, quantified and stochastically quantified formulas. We present simple yet general techniques to characterize simultaneously, the complexity or efficient approximability of a number of versions/variants of the problems SAT(S), Q-SAT(S), S-SAT(S),MAX-Q-SAT(S) etc., for many different such D,C,S,T. These versions/variants include decision, counting, maximization and approximate maximization problems, for unquantified, quantified and stochastically quantified formulas. Our unified approach is based on the following two basic concepts: (i) strongly-local replacements/reductions and (ii) relational/algebraic representability. Some of the results extend the earlier results in [Pa85,LMP99,CF+93,CF+94] Our techniques and results reported here also provide significant steps towards obtaining dichotomy theorems, for a number of the problems above, including the problems MAX-Q-SAT(S), and MAX-S-SAT(S). The discovery of such dichotomy theorems, for unquantified formulas, has received significant recent attention in the literature [CF+93, CF+94, Cr95, KSW97]. Keywords: NP-hardness; Approximation Algorithms; PSPACE-hardness; Quantified and Stochastic Constraint Satisfaction Problems.
The Vainshtein mechanism beyond the quasi-static approximation
Hans A. Winther; Pedro G. Ferreira
2015-05-13
Theories of modified gravity, in both the linear and fully non-linear regime, are often studied under the assumption that the evolution of the new (often scalar) degree of freedom present in the theory is quasi-static. This approximation significantly simplifies the study of the theory, and one often has good reason to believe that it should hold. Nevertheless it is a crucial assumption that should be explicitly checked whenever possible. In this paper we do so for the Vainshtein mechanism. By solving for the full spatial and time evolution of the Dvali-Gabadadze-Porrati and the Cubic Galileon model, in a spherical symmetric spacetime, we are able to demonstrate that the Vainshtein solution is a stable attractor and forms no matter what initial conditions we take for the scalar field. Furthermore,the quasi-static approximation is also found to be a very good approximation whenever it exists. For the best-fit Cubic Galileon model, however, we find that for deep voids at late times, the numerical solution blows up at the same time as the quasi-static solution ceases to exist. We argue that this phenomenon is a true instability of the model.
Generalized random phase approximation of soft-matter systems
Derek Frydel
2015-07-30
A general RPA approximation is developed within the liquid-state formalism as a systematic first step beyond the mean-field and toward a more realistic description of the weak-coupling regime. The resulting RPA is self-consistent and, in principle, valid for arbitrary particle interactions. RPA is introduced into the liquid-state framework via adiabatic connection -- by adiabatically switching on the particle interactions while keeping the particle density fixed at its physical value by means of an auxiliary external potential. Correlational free energy Fc involves a coupling-strength integral $\\int_0^1d{\\lambda}\\,h_{\\lambda}({\\bf r},{\\bf r}')$, where a correlation function of a fictitious system, $h_{\\lambda}({\\bf r},{\\bf r}')$, is obtained from the Ornstein-Zernike equation and an appropriate closure relation. The closure $c_{\\lambda}({\\bf r},{\\bf r}')=-\\beta\\lambda u({\\bf r},{\\bf r}')$ yields the RPA approximation. The coupling constant integral within Fc can alternatively be expressed as a summation of ring diagrams to infinite order, a known feature of RPA. The ring series can, in turn, be linked to a functional determinant known to be a solution of a Gaussian integral, therefore, connecting the RPA to the Gaussian type of an approximation.
The periodic standing-wave approximation: post-Minkowski computation
Christopher Beetle; Benjamin Bromley; Napolen Hernndez; Richard H. Price
2007-08-08
The periodic standing wave method studies circular orbits of compact objects coupled to helically symmetric standing wave gravitational fields. From this solution an approximation is extracted for the strong field, slowly inspiralling motion of black holes and binary stars. Previous work on this model has dealt with nonlinear scalar models, and with linearized general relativity. Here we present the results of the method for the post-Minkowski (PM) approximation to general relativity, the first step beyond linearized gravity. We compute the PM approximation in two ways: first, via the standard approach of computing linearized gravitational fields and constructing from them quadratic driving sources for second-order fields, and second, by solving the second-order equations as an ``exact'' nonlinear system. The results of these computations have two distinct applications: (i) The computational infrastructure for the ``exact'' PM solution will be directly applicable to full general relativity. (ii) The results will allow us to begin supplying initial data to collaborators running general relativistic evolution codes.
Lubrication approximation for thin viscous films: asymptotic behavior of nonnegative solutions
Tudorascu, Adrian
Lubrication approximation for thin viscous films: asymptotic behavior of nonnegative solutions-order nonlinear de- generate parabolic equations of lubrication approximation for thin viscous film type. The weak
COMPLEXITY&APPROXIMABILITY OF QUANTIFIED&STOCHASTIC CONSTRAINT SATISFACTION PROBLEMS
Hunt, H. B.; Marathe, M. V.; Stearns, R. E.
2001-01-01
Let D be an arbitrary (not necessarily finite) nonempty set, let C be a finite set of constant symbols denoting arbitrary elements of D, and let S and T be an arbitrary finite set of finite-arity relations on D. We denote the problem of determining the satisfiability of finite conjunctions of relations in S applied to variables (to variables and symbols in C) by SAT(S) (by SATc(S).) Here, we study simultaneously the complexity of decision, counting, maximization and approximate maximization problems, for unquantified, quantified and stochastically quantified formulas. We present simple yet general techniques to characterize simultaneously, the complexity or efficient approximability of a number of versions/variants of the problems SAT(S), Q-SAT(S), S-SAT(S),MAX-Q-SAT(S) etc., for many different such D,C ,S, T. These versions/variants include decision, counting, maximization and approximate maximization problems, for unquantified, quantified and stochastically quantified formulas. Our unified approach is based on the following two basic concepts: (i) strongly-local replacements/reductions and (ii) relational/algebraic represent ability. Some of the results extend the earlier results in [Pa85,LMP99,CF+93,CF+94O]u r techniques and results reported here also provide significant steps towards obtaining dichotomy theorems, for a number of the problems above, including the problems MAX-&-SAT( S), and MAX-S-SAT(S). The discovery of such dichotomy theorems, for unquantified formulas, has received significant recent attention in the literature [CF+93,CF+94,Cr95,KSW97
Nonlocal effective medium approximation for metallic nanorod metamaterials
Geng, Tao; Gao, Jie; Yang, Xiaodong
2015-01-01
We present an analytical nonlocal effective medium approximation to describe the optical nonlocal effects in metallic nanorod metamaterials based on Mie scattering theory. It is shown that the developed nonlocal effective medium theory can predict a coexistence state of two modes around the epsilon-near-zero region, where strong optical nonlocal effects lead to the behavior of both positive refraction and negative refraction in the nanorod metamaterials. Outside of the coexistence region, only one mode can be excited and its behavior can be well described using the local effective medium theory.
Invariant-based pulse engineering without rotating wave approximation
S. Ibez; Yi-Chao Li; Xi Chen; J. G. Muga
2015-07-02
We inverse engineer realizable time-dependent semiclassical pulses to invert or manipulate a two- level system faster than adiabatically when the rotating-wave approximation cannot be applied. Different inversion routes, based on a counterdiabatic approach or invariants, lead quite generally to singular fields. Making use of the relation between the invariants of motion and the Hamiltonian, and canceling the troublesome singularities, an inversion scheme is put forward for the regime in which the pulse spans few oscillations. For many oscillations an alternative numerical minimization method is proposed and demonstrated.
Analytical Approximation for 2-D Nonlinear Periodic Deep Water Waves
Saleh Tanveer
2013-09-20
A recently developed method has been extended to a nonlocal equation arising in steady water wave propagation in two dimensions. We obtain analyic approximation of steady water wave solution in two dimensions with rigorous error bounds for a set of parameter values that correspond to heights slightly smaller than the critical. The wave shapes are shown to be analytic. The method presented in quite general and does not assume smallness of wave height or steepness and can be readily extended to other interfacial problems involving Laplace's equation.
Breakdown of the Dipole Approximation in Strong-Field Ionization
A. Ludwig; J. Maurer; B. W. Mayer; C. R. Phillips; L. Gallmann; U. Keller
2014-10-02
We report the breakdown of the electric dipole approximation in the long-wavelength limit in strong-field ionization with linearly polarized few-cycle mid-infrared laser pulses at intensities on the order of 10$^{13}$ W/cm$^2$. Photoelectron momentum distributions were recorded by velocity map imaging and projected onto the beam propagation axis. We observe an increasing shift of the peak of this projection opposite to the beam propagation direction with increasing laser intensities. From a comparison with semi-classical simulations, we identify the combined action of the magnetic field of the laser pulse and the Coulomb potential as origin of our observations.
Compton scattering from positronium and validity of the impulse approximation
Kaliman, Z.; Pisk, K.; Pratt, R. H.
2011-05-15
The cross sections for Compton scattering from positronium are calculated in the range from 1 to 100 keV incident photon energy. The calculations are based on the A{sup 2} term of the photon-electron or photon-positron interaction. Unlike in hydrogen, the scattering occurs from two centers and the interference effect plays an important role for energies below 8 keV. Because of the interference, the criterion for validity of the impulse approximation for positronium is more restrictive compared to that for hydrogen.
Approximation Algorithms for Wireless Link Scheduling with Flexible Data Rates
Kesselheim, Thomas
2012-01-01
We consider scheduling problems in wireless networks with respect to flexible data rates. That is, more or less data can be transmitted per time depending on the signal quality, which is determined by the signal-to-interference-plus-noise ratio (SINR). Each wireless link has a utility function mapping SINR values to the respective data rates. We have to decide which transmissions are performed simultaneously and (depending on the problem variant) also which transmission powers are used. In the capacity-maximization problem, one strives to maximize the overall network throughput, i.e., the summed utility of all links. For arbitrary utility functions (not necessarily continuous ones), we present an O(log n)-approximation when having n communication requests. This algorithm is built on a constant-factor approximation for the special case of the respective problem where utility functions only consist of a single step. In other words, each link has an individual threshold and we aim at maximizing the number of lin...
Communication: Random phase approximation renormalized many-body perturbation theory
Bates, Jefferson E.; Furche, Filipp, E-mail: filipp.furche@uci.edu [Department of Chemistry, University of California, Irvine, 1102 Natural Sciences II, Irvine, California 92697-2025 (United States)] [Department of Chemistry, University of California, Irvine, 1102 Natural Sciences II, Irvine, California 92697-2025 (United States)
2013-11-07
We derive a renormalized many-body perturbation theory (MBPT) starting from the random phase approximation (RPA). This RPA-renormalized perturbation theory extends the scope of single-reference MBPT methods to small-gap systems without significantly increasing the computational cost. The leading correction to RPA, termed the approximate exchange kernel (AXK), substantially improves upon RPA atomization energies and ionization potentials without affecting other properties such as barrier heights where RPA is already accurate. Thus, AXK is more balanced than second-order screened exchange [A. Grneis et al., J. Chem. Phys. 131, 154115 (2009)], which tends to overcorrect RPA for systems with stronger static correlation. Similarly, AXK avoids the divergence of second-order Mller-Plesset (MP2) theory for small gap systems and delivers a much more consistent performance than MP2 across the periodic table at comparable cost. RPA+AXK thus is an accurate, non-empirical, and robust tool to assess and improve semi-local density functional theory for a wide range of systems previously inaccessible to first-principles electronic structure calculations.
Takahiko Matsubara; Ayako Yoshisato; Masahiro Morikawa
1997-08-17
Among several analytic approximations for the growth of density fluctuations in the expanding Universe, Zel'dovich approximation in Lagrangian coordinate scheme is known to be unusually accurate even in mildly non-linear regime. This approximation is very similar to the Pad\\'e approximation in appearance. We first establish, however, that these two are actually different and independent approximations with each other by using a model of spheroidal mass collapse. Then we propose Pad\\'e-prescribed Zel'dovich-type approximations and demonstrate, within this model, that they are much accurate than any other known nonlinear approximations.
Approximate Weighted Matching On Emerging Manycore and Multithreaded Architectures
Halappanavar, Mahantesh; Feo, John T.; Villa, Oreste; Tumeo, Antonino; Pothen, Alex
2012-11-30
Graph matching is a prototypical combinatorial problem with many applications in computer science and scientific computing, but algorithms for computing optimal matchings are challenging to parallelize. Approximate matching algorithms provide an alternate route for parallelization, and in many contexts compute near-optimal matchings for large-scale graphs. We present sharedmemory parallel implementations for computing half-approximate weighted matching on state-of-the-art multicore (Intel Nehalem and AMD Magny-Cours), manycore (Nvidia Tesla and Nvidia Fermi) and massively multithreaded (Cray XMT) platforms. We provide two implementations: the first implementation uses shared work queues, and is suited to all these platforms; the second implementation is based on dataflow principles, and exploits the architectural features of the Cray XMT. Using a carefully chosen dataset that exhibits characteristics from a wide range of real-world applications, we show scalable performance across different platforms. In particular, for one instance of the input, an R-MAT graph (RMAT-G), we show speedups of: about 32 on 48 cores of an AMD Magny-Cours; 7 on 8 cores of Intel Nehalem; 3 on Nvidia Tesla and 10 on Nvidia Fermi relative to one core of Intel Nehalem; and 60 on 128 processors of Cray XMT. We demonstrate good weak and strong scaling for graphs with up to a billion edges using up to 12, 800 threads. Given the breadth of this work, we focus on simplicity and portability of software rather than excessive fine-tuning for each platform. To the best of our knowledge, this is the first such large-scale study of the half-approximate weighted matching problem on shared-memory platforms. Driven by the critical enabling role of combinatorial algorithms such as matching in scientific computing and the emergence of informatics applications, there is a growing demand to support irregular computations on current and future computing platforms. In this context, we evaluate the capability of emerging multithreaded platforms to tolerate latency induced by irregular memory access patterns, and to support fine-grained parallelism via light-weight synchronization mechanisms. By contrasting the architectural features of these platforms against the Cray XMT, which is specifically designed to support irregular memory-intensive applications, we delineate the impact of these choices on performance.
Reduced Operator Approximation for Modelling Open Quantum Systems
Agnieszka Werpachowska
2015-08-05
We present the Reduced Operator Approximation: a simple, physically transparent and computationally efficient method of modelling open quantum systems. It employs the Heisenberg picture of the quantum dynamics, which allows us to focus on the system degrees of freedom in a natural and easy way. We describe different variants of the method, low- and high-order in the system-bath interaction operators, defining them for either general quantum harmonic oscillator baths or specialising them for independent baths with Lorentzian spectral densities. Its wide applicability is demonstrated on the examples of systems coupled to different baths (with varying system-bath interaction strength and bath memory length), and compared with the exact pseudomode and the popular quantum state diffusion approach. The method captures the decoherence of the system interacting with the bath, while conserving the total energy. Our results suggest that quantum coherence effects persist in open quantum systems for much longer times than previously thought.
Surface wake in the random-phase approximation
Garcia de Abajo, F.J. ); Echenique, P.M. )
1993-11-01
The scalar-electric-potential distribution set up by an ion traveling in the vicinity of a plane solid-vacuum interface, that is, the surface-wake potential, is investigated with the specular-reflection model to describe the response of the surface and with the random-phase approximation for the dielectric function of the bulk material. This permits us to address the study of the low-velocity surface wake: the static potential is found to have a dip at the position of the ion; that dip is shifted towards the direction opposite to the velocity vector for velocities smaller than the threshold of creation of plasmons ([approx]1.3[ital v][sub [ital F
Procedures for realizing an approximate universal NOT gate
Jeongho Bang; Seung-Woo Lee; Hyunseok Jeong; Jinhyoung Lee
2012-12-19
We consider procedures to realize an approximate universal NOT gate in terms of average fidelity and fidelity deviation. The average fidelity indicates the optimality of operation on average, while the fidelity deviation does the universality of operation. We show that one-qubit operations have a sharp trade-off relation between average fidelity and fidelity deviation, and two-qubit operations show a looser trade-off relation. The genuine universality holds for operations of more than two qubits, and those of even more qubits are beneficial to compensating imperfection of control. In addition, we take into account operational noises which contaminate quantum operation in realistic circumstances. We show that the operation recovers from the contamination by a feedback procedure of differential evolution. Our feedback scheme is also applicable to finding an optimal and universal operation of NOT.
Pion - Nucleon Bremsstrahlung beyond the Soft-Photon approximation
A. Mariano
2000-04-06
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 the momentum-shell effects. The double differential distribution of photons is computed for 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 behaviour of the different T-matrices under consideration. Finally an alternative simpler dynamical model that incorporates the unstable character of the isobar-$\\Delta(1232)$ through a complex mass, is presented. As we will see it is suitable for the study of the magnetic moment of the resonance.
A renormalisation group method. II. Approximation by local polynomials
David C. Brydges; Gordon Slade
2014-11-25
This paper is the second in a series devoted to the development of a rigorous renormalisation group method for lattice field theories involving boson fields, fermion fields, or both. The method is set within a normed algebra $\\mathcal{N}$ of functionals of the fields. In this paper, we develop a general method---localisation---to approximate an element of $\\mathcal{N}$ by a local polynomial in the fields. From the point of view of the renormalisation group, the construction of the local polynomial corresponding to $F$ in $\\mathcal{N}$ amounts to the extraction of the relevant and marginal parts of $F$. We prove estimates relating $F$ and its corresponding local polynomial, in terms of the $T_{\\phi}$ semi-norm introduced in part I of the series.
Particle-particle random phase approximation applied to Beryllium isotopes
Guillaume Blanchon; Nicole Vinh Mau; Angela Bonaccorso; Marc Dupuis; Nathalie Pillet
2010-07-16
This work is dedicated to the study of even-even 8-14 Be isotopes using the particle-particle Random Phase Approximation that accounts for two-body correlations in the core nucleus. A better description of energies and two-particle amplitudes is obtained in comparison with models assuming a neutron closed-shell (or subshell) core. A Wood-Saxon potential corrected by a phenomenological particle-vibration coupling term has been used for the neutron-core interaction and the D1S Gogny force for the neutron-neutron interaction. Calculated ground state properties as well as excited state ones are discussed and compared to experimental data. In particular, results suggest the same 2s_1/2-1p_1/2 shell inversion in 13Be as in 11Be.
Mixed series in ultraspherical polynomials and their approximation properties
Sharapudinov, I I
2003-04-30
New (mixed) series in ultraspherical polynomials P{sub n}{sup {alpha}}{sup ,{alpha}}(x) are introduced. The basic difference between a mixed series in the polynomials P{sub n}{sup {alpha}}{sup ,{alpha}}(x) and a Fourier series in the same polynomials is as follows: a mixed series contains terms of the form (2{sup r}f{sub r,k}{sup {alpha}})/(k+2{alpha}){sup [r]}) P{sub k+r}{sup {alpha}}{sup -r,{alpha}}{sup -r}(x), where 1{<=}r is an integer and f{sub r,k}{sup {alpha}} is the kth Fourier coefficient of the derivative f{sup (r)}(x) with respect to the ultraspherical polynomials P{sub k}{sup {alpha}}{sup ,{alpha}}(x). It is shown that the partial sums Y{sub n+2r}{sup {alpha}}(f,x) of a mixed series in the polynomial P{sub k}{sup {alpha}}{sup ,{alpha}}(x) contrast favourably with Fourier sums S{sub n}{sup {alpha}}(f,x) in the same polynomials as regards their approximation properties in classes of differentiable and analytic functions, and also in classes of functions of variable smoothness. In particular, the Y{sub n+2r}{sup {alpha}}(f,x) can be used for the simultaneous approximation of a function f(x) and its derivatives of orders up to (r- 1), whereas the S{sub n}{sup {alpha}}(f,x) are not suitable for this purpose.
Polymer quantization and the saddle point approximation of partition functions
Hugo A. Morales Tcotl; Daniel H. Orozco Borunda; Saeed Rastgoo
2015-07-31
The saddle point approximation of the path integral partition functions is an important way of deriving the thermodynamical properties of black holes. However, there are certain black hole models and some mathematically analog mechanical models for which this method can not be applied directly. This is due to the fact that their action evaluated on a classical solution is not finite and its first variation does not vanish for all consistent boundary conditions. These problems can be dealt with by adding a counter-term to the classical action, which is a solution of the corresponding Hamilton-Jacobi equation. In this work we study the effects of polymer quantization on a mechanical model presenting the aforementioned difficulties and contrast it with the above counter-term method. This type of quantization for mechanical models is motivated by the loop quantization of gravity which is known to play a role in the thermodynamics of black holes systems. The model we consider is a non relativistic particle in an inverse square potential and analyze two polarizations of the polymer quantization in which either the position or the momentum is discrete. In the former case, Thiemann's regularization is applied to represent the inverse power potential but we still need to incorporate the Hamilton-Jacobi counter-term which is now modified by polymer corrections. In the latter, momentum discrete case however, such regularization could not be implemented. Yet, remarkably, due to the fact that the position is bounded, we do not need a Hamilton-Jacobi counter-term in order to have a well defined saddle point approximation. Further developments and extensions are commented upon in the discussion.
Polymer quantization and the saddle point approximation of partition functions
Hugo A. Morales-Tcotl; Daniel H. Orozco-Borunda; Saeed Rastgoo
2015-11-10
The saddle point approximation of the path integral partition functions is an important way of deriving the thermodynamical properties of black holes. However, there are certain black hole models and some mathematically analog mechanical models for which this method cannot be applied directly. This is due to the fact that their action evaluated on a classical solution is not finite and its first variation does not vanish for all consistent boundary conditions. These problems can be dealt with by adding a counterterm to the classical action, which is a solution of the corresponding Hamilton-Jacobi equation. In this work we study the effects of polymer quantization on a mechanical model presenting the aforementioned difficulties and contrast it with the above counterterm method. This type of quantization for mechanical models is motivated by the loop quantization of gravity which is known to play a role in the thermodynamics of black hole systems. The model we consider is a nonrelativistic particle in an inverse square potential, and analyze two polarizations of the polymer quantization in which either the position or the momentum is discrete. In the former case, Thiemann's regularization is applied to represent the inverse power potential but we still need to incorporate the Hamilton-Jacobi counterterm which is now modified by polymer corrections. In the latter, momentum discrete case however, such regularization could not be implemented. Yet, remarkably, owing to the fact that the position is bounded, we do not need a Hamilton-Jacobi counterterm in order to have a well-defined saddle point approximation. Further developments and extensions are commented upon in the discussion.
Asymptotic safety in the f(R) approximation
Juergen A. Dietz; Tim R. Morris
2013-01-28
In the asymptotic safety programme for quantum gravity, it is important to go beyond polynomial truncations. Three such approximations have been derived where the restriction is only to a general function f(R) of the curvature R>0. We confront these with the requirement that a fixed point solution be smooth and exist for all non-negative R. Singularities induced by cutoff choices force the earlier versions to have no such solutions. However, we show that the most recent version has a number of lines of fixed points, each supporting a continuous spectrum of eigen-perturbations. We uncover and analyse the first five such lines. Sensible fixed point behaviour may be achieved if one consistently incorporates geometry/topology change. As an exploratory example, we analyse the equations analytically continued to R<0, however we now find only partial solutions.We show how these results are always consistent with, and to some extent can be predicted from, a straightforward analysis of the constraints inherent in the equations.
Approximating Ground and Excited State Energies on a Quantum Computer
Stuart Hadfield; Anargyros Papageorgiou
2015-08-06
Approximating ground and a fixed number of excited state energies, or equivalently low order Hamiltonian eigenvalues, is an important but computationally hard problem. Typically, the cost of classical deterministic algorithms grows exponentially with the number of degrees of freedom. Under general conditions, and using a perturbation approach, we provide a quantum algorithm that produces estimates of a constant number $j$ of different low order eigenvalues. The algorithm relies on a set of trial eigenvectors, whose construction depends on the particular Hamiltonian properties. We illustrate our results by considering a special case of the time-independent Schr\\"odinger equation with $d$ degrees of freedom. Our algorithm computes estimates of a constant number $j$ of different low order eigenvalues with error $O(\\epsilon)$ and success probability at least $\\frac34$, with cost polynomial in $\\frac{1}{\\epsilon}$ and $d$. This extends our earlier results on algorithms for estimating the ground state energy. The technique we present is sufficiently general to apply to problems beyond the application studied in this paper.
Polymer quantization and the saddle point approximation of partition functions
Tcotl, Hugo A Morales; Rastgoo, Saeed
2015-01-01
The saddle point approximation of the path integral partition functions is an important way of deriving the thermodynamical properties of black holes. However, there are certain black hole models and some mathematically analog mechanical models for which this method can not be applied directly. This is due to the fact that their action evaluated on a classical solution is not finite and its first variation does not vanish for all consistent boundary conditions. These problems can be dealt with by adding a counter-term to the classical action, which is a solution of the corresponding Hamilton-Jacobi equation. In this work we study the effects of polymer quantization on a mechanical model presenting the aforementioned difficulties and contrast it with the above counter-term method. This type of quantization for mechanical models is motivated by the loop quantization of gravity which is known to play a role in the thermodynamics of black holes systems. The model we consider is a non relativistic particle in an i...
Quasilocalized charge approximation in strongly coupled plasma physics
Golden, Kenneth I. [Department of Mathematics and Statistics, Department of Physics, University of Vermont, Burlington, Vermont 05401-1455 (United States)] [Department of Mathematics and Statistics, Department of Physics, University of Vermont, Burlington, Vermont 05401-1455 (United States); Kalman, Gabor J. [Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467 (United States)] [Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467 (United States)
2000-01-01
The quasilocalized charge approximation (QLCA) was proposed in 1990 [G. Kalman and K. I. Golden, Phys. Rev. A 41, 5516 (1990)] as a formalism for the analysis of the dielectric response tensor and collective mode dispersion in strongly coupled Coulomb liquids. The approach is based on a microscopic model in which the charges are quasilocalized on a short-time scale in local potential fluctuations. The authors review the application of the QLC approach to a variety of systems which can exhibit strongly coupled plasma behavior: (i) the one-component plasma (OCP) model in three dimensions (e.g., laser-cooled trapped ions) and (ii) in two dimensions (e.g., classical 2D electron liquid trapped above the free surface of liquid helium), (iii) binary ionic mixture in a neutralizing uniform background (e.g., carbon-oxygen white dwarf interiors), (iv) charged particle bilayers (e.g., semiconductor electronic bilayers), and (v) charged particles in polarizable background (e.g., laboratory dusty plasmas). (c) 2000 American Institute of Physics.
Convergence analysis of the thermal discrete dipole approximation
Edalatpour, Sheila; Trueax, Tyler; Backman, Roger; Francoeur, Mathieu
2015-01-01
The thermal discrete dipole approximation (T-DDA) is a numerical approach for modeling near-field radiative heat transfer in complex three-dimensional geometries. In this work, the convergence of the T-DDA is investigated using the exact solution for two spheres separated by a vacuum gap. The error associated with the T-DDA is reported for various size parameters, refractive indices and vacuum gap sizes. The results reveal that for a fixed number of sub-volumes, the accuracy of the T-DDA degrades as the refractive index and the sphere diameter to gap ratio increase. A converging trend is observed as the number of sub-volumes increases. The large computational requirements associated with increasing the number of sub-volumes, and the shape error induced by large sphere diameter to gap ratios, are mitigated by using a non-uniform discretization scheme. Non-uniform discretization is shown to significantly accelerate the convergence of the T-DDA, and is thus recommended for near-field thermal radiation simulation...
DARCY'S FLOW WITH PRESCRIBED CONTACT ANGLE WELL-POSEDNESS AND LUBRICATION APPROXIMATION
DARCY'S FLOW WITH PRESCRIBED CONTACT ANGLE WELL-POSEDNESS AND LUBRICATION APPROXIMATION HANS KN at the contact point. In the so called lubrication approximation (long-wave limit) we show that the solutions
Journal of Approximation Theory 147 (2007) 185195 www.elsevier.com/locate/jat
Elad, Michael
2007-01-01
Journal of Approximation Theory 147 (2007) 185195 www.elsevier.com/locate/jat On Lebesgue.L. Donoho et al. / Journal of Approximation Theory 147 (2007) 185195 Inequality (1.1) relates the error
Local random quantum circuits are approximate polynomial-designs
Fernando G. S. L. Brandao; Aram W. Harrow; Michal Horodecki
2015-08-13
We prove that local random quantum circuits acting on n qubits composed of O(t^{10} n^2) many nearest neighbor two-qubit gates form an approximate unitary t-design. Previously it was unknown whether random quantum circuits were a t-design for any t > 3. The proof is based on an interplay of techniques from quantum many-body theory, representation theory, and the theory of Markov chains. In particular we employ a result of Nachtergaele for lower bounding the spectral gap of frustration-free quantum local Hamiltonians; a quasi-orthogonality property of permutation matrices; a result of Oliveira which extends to the unitary group the path-coupling method for bounding the mixing time of random walks; and a result of Bourgain and Gamburd showing that dense subgroups of the special unitary group, composed of elements with algebraic entries, are infty-copy tensor-product expanders. We also consider pseudo-randomness properties of local random quantum circuits of small depth and prove that circuits of depth O(t^{10}n) constitute a quantum t-copy tensor-product expander. The proof also rests on techniques from quantum many-body theory, in particular on the detectability lemma of Aharonov, Arad, Landau, and Vazirani. We give applications of the results to cryptography, equilibration of closed quantum dynamics, and the generation of topological order. In particular we show the following pseudo-randomness property of generic quantum circuits: Almost every circuit U of size O(n^k) on n qubits cannot be distinguished from a Haar uniform unitary by circuits of size O(n^{(k-9)/11}) that are given oracle access to U.
Comparison of moment-closure approximations for stochastic chemical kinetics
David Schnoerr; Guido Sanguinetti; Ramon Grima
2015-08-07
In recent years moment-closure approximations (MA) of the chemical master equation have become a popular method for the study of stochastic effects in chemical reaction systems. Several different MA methods have been proposed and applied in the literature, but it remains unclear how they perform with respect to each other. In this paper we study the normal, Poisson, log-normal and central-moment-neglect MAs by applying them to understand the stochastic properties of chemical systems whose deterministic rate equations show the properties of bistability, ultrasensitivity and oscillatory behaviour. Our results suggest that the normal MA is favourable over the other studied MAs. In particular we found that (i) the size of the region of parameter space where a closure gives physically meaningful results, e.g. positive mean and variance, is considerably larger for the normal closure than for the other three closures; (ii) the accuracy of the predictions of the four closures (relative to simulations using the stochastic simulation algorithm) is comparable in those regions of parameter space where all closures give physically meaningful results; (iii) the Poisson and log-normal MAs are not uniquely defined for systems involving conservation laws in molecule numbers. We also describe the new software package MOCA which enables the automated numerical analysis of various MA methods in a graphical user interface and which was used to perform the comparative analysis presented in this paper. MOCA allows the user to develop novel closure methods and can treat polynomial, non-polynomial, as well as time-dependent propensity functions, thus being applicable to virtually any chemical reaction system.
Markov Jump Processes Approximating a Non-Symmetric Generalized Diffusion
Limic, Nedzad
2011-08-15
Consider a non-symmetric generalized diffusion X( Dot-Operator ) in Double-Struck-Capital-R {sup d} determined by the differential operator A(x) = -{Sigma}{sub ij} {partial_derivative}{sub i}a{sub ij}(x){partial_derivative}{sub j} + {Sigma}{sub i} b{sub i}(x){partial_derivative}{sub i}. In this paper the diffusion process is approximated by Markov jump processes X{sub n}( Dot-Operator ), in homogeneous and isotropic grids G{sub n} Subset-Of Double-Struck-Capital-R {sup d}, which converge in distribution in the Skorokhod space D([0,{infinity}), Double-Struck-Capital-R {sup d}) to the diffusion X( Dot-Operator ). The generators of X{sub n}( Dot-Operator ) are constructed explicitly. Due to the homogeneity and isotropy of grids, the proposed method for d{>=}3 can be applied to processes for which the diffusion tensor {l_brace}a{sub ij}(x){r_brace}{sub 11}{sup dd} fulfills an additional condition. The proposed construction offers a simple method for simulation of sample paths of non-symmetric generalized diffusion. Simulations are carried out in terms of jump processes X{sub n}( Dot-Operator ). For piece-wise constant functions a{sub ij} on Double-Struck-Capital-R {sup d} and piece-wise continuous functions a{sub ij} on Double-Struck-Capital-R {sup 2} the construction and principal algorithm are described enabling an easy implementation into a computer code.
Pugh, Mary
THE LUBRICATION APPROXIMATION FOR THIN VISCOUS FILMS: REGULARITY AND LONG TIME BEHAVIOR OF WEAK = - · (f(h) h) in one space dimension. This equation, derived from a `lubrication approximation', models from a `lubrication approximation', models surface tension dominated motion of thin viscous films
Pugh, Mary
THE LUBRICATION APPROXIMATION FOR THIN VISCOUS FILMS: REGULARITY AND LONG TIME BEHAVIOR OF WEAK t = -# · (f(h)##h) in one space dimension. This equation, derived from a `lubrication approximation', models. This equation, derived from a `lubrication approximation', models surface tension dominated motion of thin
Matrix multiplication over word-size prime fields using Bini's approximate formula
Paris-Sud XI, Universit de
Matrix multiplication over word-size prime fields using Bini's approximate formula Brice Boyer Jean-Guillaume Dumas Abstract Bini's approximate formula (or border rank) for matrix multiplication achieves a better the approximate formula in the special case where the ring is Z/pZ. Besides, we show an implemen- tation la
A New Look at the High Frequency Boundary Element and Rayleigh Integral Approximations
Seybert, Andrew F.
03NVC-114 A New Look at the High Frequency Boundary Element and Rayleigh Integral Approximations D of Automotive Engineers, Inc. ABSTRACT This paper revisits the popular Rayleigh integral approximation, and also to the Rayleigh integral. Both methods are approximations to the boundary integral equation, and can solve
An analytic approximation to the Diffusion Coefficient for the periodic Lorentz Gas
C. Angstmann; G. P. Morriss
2012-02-14
An approximate stochastic model for the topological dynamics of the periodic triangular Lorentz gas is constructed. The model, together with an extremum principle, is used to find a closed form approximation to the diffusion coefficient as a function of the lattice spacing. This approximation is superior to the popular Machta and Zwanzig result and agrees well with a range of numerical estimates.
Approximate Dynamic Programming for Dynamic Capacity Allocation with Multiple Priority Levels
Topaloglu, Huseyin
Approximate Dynamic Programming for Dynamic Capacity Allocation with Multiple Priority Levels In this paper, we consider a quite general dynamic capacity allocation problem. There is a fixed amount of daily to construct separable approximations to the value functions. We use the value function approximations for two
Comparison of Approximation Methods for Computing Tolerance Factors for a Multivariate
Krishnamoorthy, Kalimuthu
Comparison of Approximation Methods for Computing Tolerance Factors for a Multivariate Normal approximation methods for computing the tolerance factors of a multivariate normal population. These approximate on the multivariate setup is rather limited, how- ever. The first attempt at constructing tolerance regions
A mixed formulation for the direct approximation -weighted controls for the linear heat
Boyer, Edmond
A mixed formulation for the direct approximation of L2 -weighted controls for the linear heat of null controls for the linear heat equa- tion. The goal is to compute approximations of controls-Cara & M¨unch, Strong convergence approximations of null controls for the 1D heat equation, 2013], a so
Approximate and Fiducial Confidence Intervals for the Difference Between Two Binomial Proportions
Krishnamoorthy, Kalimuthu
Approximate and Fiducial Confidence Intervals for the Difference Between Two Binomial Proportions K of estimating the difference between two binomial proportions is considered. Closed-form approximate confidence intervals (CIs), and a fiducial CI for the difference between proportions are proposed. The approximate CIs
PreDVS: Preemptive Dynamic Voltage Scaling for Real-time Systems using Approximation Scheme
Mishra, Prabhat
, dynamic voltage scal- ing, approximation algorithm 1. INTRODUCTION Energy conservation has been the main to save energy is that linear reduction in the supply voltage leads to approximately linear slow downPreDVS: Preemptive Dynamic Voltage Scaling for Real-time Systems using Approximation Scheme Weixun
Validity of Born Approximation for Nuclear Scattering in Path Integral Representation
M. R. Pahlavani; R. Morad
2009-07-01
The first and second Born approximation are studied with the path integral representation for $ {\\cal T} $ matrix. The $ {\\cal T}$ matrix is calculated for Woods-Saxon potential scattering. To make corresponding integrals solvable analytically, an approximate function for the Woods-Saxon potential is used. Finally it shown that the Born series is converge at high energies and orders higher than two in Born approximation series can be neglected.
Approximate life-cycle assessment of product concepts using learning systems
Sousa, Ins (Maria Ins Silva Sousa), 1972-
2002-01-01
This thesis develops an approximate, analytically based environmental assessment method that provides fast evaluations of product concepts. Traditional life-cycle assessment (LCA) studies and their streamlined analytical ...
A complete analytic inversion of supernova lines in the Sobolev approximation
Kasen, Daniel; Branch, David; Baron, E.; Jeffery, David
2001-01-01
D . & Branch, D . 1990, in Supernovae, ed. J . C . Wheeler &radia tive transfer supernovae Lawrence Berkeley Nationalgradients, such as supernovae. The Sobolev approximation has
The complexity of approximate Nash equilibrium in congestion games with negative delays
Magniez, Frédéric
The complexity of approximate Nash equilibrium in congestion games with negative delays Fr of the complexity of computing an - approximate Nash equilibrium in symmetric congestion games from the case that in symmetric games with increasing delay functions and with - bounded jump the -Nash dynamic converges
Polylogarithmic Supports are required for Approximate Well-Supported Nash Equilibria
Vetta, Adrian
Polylogarithmic Supports are required for Approximate Well-Supported Nash Equilibria below 2@math.mcgill.ca Abstract. In an -approximate Nash equilibrium, a player can gain at most in expectation by unilateral deviation. An -well-supported ap- proximate Nash equilibrium has the stronger requirement that every pure
How hard is it to approximate the best Nash equilibrium? IBM Almaden
Krauthgamer, Robert
How hard is it to approximate the best Nash equilibrium? Elad Hazan IBM Almaden ehazan for a PTAS for Nash equilibrium in a two-player game seeks to circumvent the PPAD- completeness of an (exact) Nash equilibrium by find- ing an approximate equilibrium, and has emerged as a major open question
Approximate Nash Equilibria for Multi-player Games Sebastien Hemon1,2
Fondements et Applications, Universit Paris 7
Approximate Nash Equilibria for Multi-player Games Sebastien Hemon1,2 , Michel de Rougemont1 approximate Nash equilibria in the additive and multiplicative sense, where the number of pure strategies. In the additive case we show that for 0 Nash equilibrium with support size 2r ln(nr+r) 2
Deviations from piecewise linearity in the solid-state limit with approximate density functionals
Baer, Roi
Deviations from piecewise linearity in the solid-state limit with approximate density functionals (2015) Deviations from piecewise linearity in the solid-state limit with approximate density functionals functional methods J. Chem. Phys. 141, 124123 (2014); 10.1063/1.4896455 Thermally-assisted-occupation density
Every linear threshold function has a low-weight approximator Rocco A. Servedio
Servedio, Rocco
Every linear threshold function has a low-weight approximator Rocco A. Servedio Department threshold function f on n Boolean vari- ables, we construct a linear threshold function g which dis- agrees of ( n) on the weights required to approximate a particular linear thresh- old function. We give two
Dyna-Style Planning with Linear Function Approximation and Prioritized Sweeping
Szepesvari, Csaba
Dyna-Style Planning with Linear Function Approximation and Prioritized Sweeping Richard S. Sutton to linear function approximation. Dyna- style planning proceeds by generating imaginary experience from Abstract We consider the problem of efficiently learning optimal control policies and value functions over
Botti, Silvana
Motivation Green's functions The GW Approximation The Bethe-Salpeter Equation Introduction to Green's functions Matteo Gatti ETSF Users' Meeting and Training Day Ecole Polytechnique - 22 October 2010 #12;bg=whiteMotivation Green's functions The GW Approximation The Bethe-Salpeter Equation Outline 1 Motivation 2 Green
Validation of the correctness of the Hald approximation in assessing tolerance
Gurevich, M. I., E-mail: gur.m@mail.ru; Kalugin, M. A.; Chukbar, B. K. [National Research Center Kurchatov Institute (Russian Federation)
2014-12-15
An analysis was performed of the correctness of employing the approximate formula which is widely used when assessing tolerances in the results of regression analysis. The correctness of approximation with the frequently used ratio between the probability and significance level equal to 95/95 is demonstrated. Conditions of application of the formula under stricter requirements, for example, 99/99, are formulated.
Approximation Technique of Finite Capacity Queuing Networks Exploiting Petri Net Analysis
Gribaudo, Marco
Approximation Technique of Finite Capacity Queuing Networks Exploiting Petri Net Analysis Marco for deriving approximate measures for finite capacity queuing networks. The fact that buffers have finite capacity makes the analysis of such networks very difficult. Indeed, FC-QNs do not have a product form
Ada Numerica (1998), pp. 51-150 Cambridge University Press, 1998 Nonlinear approximation
DeVore, Ronald
1998-01-01
References 146 1. Nonlinear approximation: an overview The fundamental problem of approximation theory functionals applied to the target function are known. This information is then used to construct by certain smoothness conditions which are significantly weaker than required in the linear theory. Emphasis
Semi-analytic approximations for production of atmospheric muons and neutrinos
Thomas K. Gaisser
2001-04-19
Simple approximations for fluxes of atmospheric muons and muon neutrinos are developed which display explicitly how the fluxes depend on primary cosmic ray energy and on features of pion production. For energies of approximately 10 GeV and above the results are sufficiently accurate to calculate response functions and to use for estimates of systematic uncertainties.
Low complexity channel models for approximating flat Rayleigh fading in network simulations
McDougall, Jeffrey Michael
2004-09-30
of the requirements f DOCTOR OF PHILOSOPHY August 2003 Major Subject: Electrical Engineering LOW COMPLEXITY CHANNEL MODELS FOR APPROXIMATING FLAT RAYLEIGH FADING IN NETWORK SIMULATIONS A Dissertation by JEFFREY MICHAEL...) ____________________________ ____________________________ Du Li Chanan Singh (Member) (Head of Department) August 2003 Major Subject: Electrical Engineering iii ABSTRACT Low Complexity Channel Models for Approximating Flat Rayleigh Fading...
Real-Time Pricing for Demand Response Based on Stochastic Approximation
Wong, Vincent
1 Real-Time Pricing for Demand Response Based on Stochastic Approximation Pedram Samadi, Student to reduce their energy expenses. Keywords: Demand response, real-time pricing, PAR minimiza- tion, stochastic approximation, simultaneous perturbation. I. INTRODUCTION Demand response (DR) is an important
Robert, Pincus
A fast, flexible, approximate technique for computing radiative transfer in inhomogeneous cloud.-J. Morcrette, A fast, flexible, approximate technique for computing radiative transfer in inhomogeneous cloud, which computes fluxes at each level. [3] The description of clouds in current LSMs is quite simple: Most
Approximations for Bit Error Probabilities in SSMA Communication Systems Using Spreading
Keller, Gerhard
Approximations for Bit Error Probabilities in SSMA Communication Systems Using Spreading Sequences@mi.uni-erlangen.de Abstract-- In previous research, we considered SSMA (spread spectrum multiple access) communication systems of spread spectrum multiple access (SSMA) communication systems, the standard Gaussian approximation (SGA
Miller, William H.
Semiclassical theory of electronically nonadiabatic dynamics: Results of a linearized approximation, California 94720 Received 6 May 1998; accepted 31 July 1998 A linearized approximation to the semiclassical easier to apply than the full SC-IVR because it linearizes the phase difference between interfering
Multinomial Approximating Models for Options Hemantha S. B. Herath* and Pranesh Kumar**
Kumar, Pranesh
, Johnson 1987, and Stulz 1982). These models are useful for valuing real options having multiple sourcesMultinomial Approximating Models for Options Hemantha S. B. Herath* and Pranesh Kumar** Business@unbc.ca; Tel: (250) 960-6671 #12;2 Multinomial Approximating Models for Options Abstract. We ensure non
Fiat, Amos
1 Mechanism Design and Approximation Our world is an interconnected collection of economic in transportation networks, and market and auc- tion design can lead to mechanisms for allocating and exchanging. #12;2 Mechanism Design and Approximation of individual strategies is complex and the space of possible
Validating a model of colon colouration using an Evolution Strategy with adaptive approximations
Rowe, Jon
Validating a model of colon colouration using an Evolution Strategy with adaptive approximations light interaction with the tissue, is aimed at correlating the histology of the colon and its colours been applied to solve it. An adaptive approximate optimisation method has been developed and applied
CONVERGENCE OF NUMERICAL APPROXIMATIONS TO A PHASE FIELD BENDING ELASTICITY MODEL OF
CONVERGENCE OF NUMERICAL APPROXIMATIONS TO A PHASE FIELD BENDING ELASTICITY MODEL OF MEMBRANE, Number 1, Pages 118 CONVERGENCE OF NUMERICAL APPROXIMATIONS TO A PHASE FIELD BENDING ELASTICITY MODEL OF MEMBRANE DEFORMATIONS QIANG DU AND XIAOQIANG WANG This paper is dedicated to Prof.Max Gunzburger
Zelikovsky, Alexander
correspond to a group of up to eight nodes in the Group #3; This work was supported by a Packard Foundation a group of up to eight virtual positions (c). The only existing approximation algorithms for the GroupA New Approximation Scheme for the Group Steiner Problem #3; C. S. Helvig Gabriel Robins Alexander
Numerical approximation of bang-bang controls for the heat equation: an optimal design approach
Paris-Sud XI, Universit de
Numerical approximation of bang-bang controls for the heat equation: an optimal design approach approximation of null controls of minimal L -norm for the linear heat equation with a bounded potential. Both the internal and boundary controllability problem of a linear heat equation with a bounded potential. Let us
Low and high frequency approximations to eigenvibrations in a string with double
Scheichl, Robert
Low and high frequency approximations to eigenvibrations in a string with double contrasts Natalia://www.bath.ac.uk/math-sci/BICS #12;Low and high frequency approximations to eigenvibrations of string with double contrasts Natalia as the order of stiffness inhomogeneity, with heavier part being softer. The limit problem for high frequency
Approximate model checking of stochastic hybrid systems , J.-P. Katoen
Abate, Alessandro
-room heating system. 1 Introduction Stochastic hybrid systems are a broad and widely applicable classApproximate model checking of stochastic hybrid systems A. Abate , J.-P. Katoen , J. Lygeros , and M. Prandini Abstract A method for approximate model checking of stochastic hybrid systems
ERROR BOUNDS FOR MONOTONE APPROXIMATION SCHEMES FOR HAMILTON-JACOBI-BELLMAN
ERROR BOUNDS FOR MONOTONE APPROXIMATION SCHEMES FOR HAMILTON-JACOBI-BELLMAN EQUATIONS GUY BARLES AND ESPEN R. JAKOBSEN Abstract. We obtain error bounds for monotone approximation schemes of Hamilton-Jacobi, (almost) smooth supersolutions for the Hamilton-Jacobi-Bellman equation. 1. Introduction This paper
Serpen, Gursel
Search for A Lyapunov Function through Empirical Approximation by Artificial Neural Nets approximator for empirical modeling of a Lyapunov function for a nonlinear dynamic system that projects stable of designing the so-called Lyapunov neural network, which empirically models a Lyapunov function, is described
A PROJECTION APPROXIMATION MINOR SUBSPACE TRACKING Scott C. Douglas and Xiaoan Sun
Douglas, Scott C.
A PROJECTION APPROXIMATION MINOR SUBSPACE TRACKING ALGORITHM Scott C. Douglas and Xiaoan Sun In this paper, we present an extension of the least-squares- based projection approximation subspace tracking-popular methods are the projection approxima- tion subspace tracking (PAST) and PAST with de ation (PASTd
A Stochastic Approximation Method to Compute Bid Prices in Network Revenue Management Problems
Topaloglu, Huseyin
A Stochastic Approximation Method to Compute Bid Prices in Network Revenue Management Problems approximation method to compute bid prices in network revenue management problems. The key idea is to visualize the total expected revenue as a function of the bid prices and to use sample path-based derivatives
Constant centrifugal potential approximation for atom-diatom chemical reaction dynamics
Takada, Shoji
Constant centrifugal potential approximation for atom-diatom chemical reaction dynamics Kengo,Myodaiji, Okazaki 444. Japan (Received 28 September 1993; accepted 8 December 1993) The constant centrifugal of such practically useful approxima- tions the constant centrifugal potential approximation (CCPA) (or the energy
Approximate Association Rule Mining Jyothsna R. Nayak and Diane J. Cook
Cook, Diane J.
1 Approximate Association Rule Mining Jyothsna R. Nayak and Diane J. Cook Department of Computer. In this paper, we describe an associate rule mining algorithm that searches for approximate association rules and Engineering Box 19015 University of Texas at Arlington Arlington, TX 76019 Office: (817) 272-3606 Fax: (817
ENERGY-PRESERVING AND STABLE APPROXIMATIONS FOR THE TWO-DIMENSIONAL SHALLOW WATER EQUATIONS
ENERGY-PRESERVING AND STABLE APPROXIMATIONS FOR THE TWO-DIMENSIONAL SHALLOW WATER EQUATIONS EITAN water equations 13 5.1. Energy stable schemes 13 5.2. Energy preserving schemes 17 6. Numerical TADMOR AND WEIGANG ZHONG Abstract. We present a systematic development of energy-stable approximations
Double-Pole Approximation in Time-Dependent Density Functional Theory
Gross, E.K.U.
Double-Pole Approximation in Time-Dependent Density Functional Theory H. Appel and E.K.U. Gross-dependent density func- tional theory (TDDFT) is given. This extends the single-pole approximation (SPA) to two strongly- coupled poles. The analysis provides both an illustration of how TDDFT works when strong exchange
Barycentric rational interpolation with no poles and high rates of approximation
Hormann, Kai
Barycentric rational interpolation with no poles and high rates of approximation Michael S. Floater to control the occurrence of poles. In this paper we propose and study a family of barycentric rational inter- polants that have no real poles and arbitrarily high approximation orders on any real interval, regardless
Asher, Sanford A.
Polarizability Approximations W. A. Al-Saidi,*, Sanford A. Asher, and Patrick Norman Department of Chemical
Convergence properties of polynomial chaos approximations for L2 random variables.
Field, Richard V., Jr. (.,; .); Grigoriu, Mircea (Cornell University, Ithaca, NY)
2007-03-01
Polynomial chaos (PC) representations for non-Gaussian random variables are infinite series of Hermite polynomials of standard Gaussian random variables with deterministic coefficients. For calculations, the PC representations are truncated, creating what are herein referred to as PC approximations. We study some convergence properties of PC approximations for L{sub 2} random variables. The well-known property of mean-square convergence is reviewed. Mathematical proof is then provided to show that higher-order moments (i.e., greater than two) of PC approximations may or may not converge as the number of terms retained in the series, denoted by n, grows large. In particular, it is shown that the third absolute moment of the PC approximation for a lognormal random variable does converge, while moments of order four and higher of PC approximations for uniform random variables do not converge. It has been previously demonstrated through numerical study that this lack of convergence in the higher-order moments can have a profound effect on the rate of convergence of the tails of the distribution of the PC approximation. As a result, reliability estimates based on PC approximations can exhibit large errors, even when n is large. The purpose of this report is not to criticize the use of polynomial chaos for probabilistic analysis but, rather, to motivate the need for further study of the efficacy of the method.
Global dynamics and inflationary center manifold and slow-roll approximants
Artur Alho; Claes Uggla
2015-01-15
We consider the familiar problem of a minimally coupled scalar field with quadratic potential in flat Friedmann-Lema\\^itre-Robertson-Walker cosmology to illustrate a number of techniques and tools, which can be applied to a wide range of scalar field potentials and problems in e.g. modified gravity. We present a global and regular dynamical systems description that yields a global understanding of the solution space, including asymptotic features. We introduce dynamical systems techniques such as center manifold expansions and use Pad\\'e approximants to obtain improved approximations for the `attractor solution' at early times. We also show that future asymptotic behavior is associated with a limit cycle, which shows that manifest self-similarity is asymptotically broken toward the future, and give approximate expressions for this behavior. We then combine these results to obtain global approximations for the attractor solution, which, e.g., might be used in the context of global measures. In addition we elucidate the connection between slow-roll based approximations and the attractor solution, and compare these approximations with the center manifold based approximants.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O O D SFederal8823 Revision 0 Approved for4:28 pm, Oct
Statistical mechanics of the nonlinear Schroedinger equation. II. Mean field approximation
Lebowitz, J.L.; Rose, H.A.; Speer, E.R.
1989-01-01
The authors investigate a mean field approximation to the statistical mechanics of complex fields with dynamics governed by the nonlinear Schroedinger equation. Such fields, whose Hamiltonian is unbounded below, may model plasmas, lasers, and other physical systems. Restricting themselves to one-dimensional systems with periodic boundary conditions, we find in the mean field approximation a phase transition from a uniform regime to a regime in which the system is dominated by solitons. They compute explicitly, as a function of temperature and density (L/sup 2/ norm), the transition point at which the uniform configuration becomes unstable to local perturbations; static and dynamic mean field approximations yield the same result.
V. Rezania; Y. Sobouti
1998-04-27
The post-Newtonian approximation of general relativistic Liouville's equation is presented. Two integrals of it, generalizations of the classical energy and angular momentum, are obtained. Polytropic models are constructed as an application.
Value Function Approximation on Non-Linear Manifolds for Robot Motor Control
Sugiyama, Masashi; Hachiya, Hirotaka; Towell, Christopher; Vijayakumar, Sethu
The least squares approach works efficiently in value function approximation, given appropriate basis functions. Because of its smoothness, the Gaussian kernel is a popular and useful choice as a basis function. However, ...
Burke, Kieron
Leading corrections to local approximations Attila Cangi, Donghyung Lee, Peter Elliott, and Kieron efficiency and accuracy. The original density functional theory was that of Thomas1 and Fermi2 TF , in which
IMPROVED QUASI-STEADY-STATE-APPROXIMATION METHODS FOR ATMOSPHERIC CHEMISTRY INTEGRATION
Jay, Laurent O.
IMPROVED QUASI-STEADY-STATE-APPROXIMATION METHODS FOR ATMOSPHERIC CHEMISTRY INTEGRATION L. O. JAY are presented. Key words. atmospheric chemistry, stiff ordinary differential equations, quasi PII. S1064827595283033 1. Introduction. As our scientific understanding of atmospheric chemistry
Horowitz, Jordan M
2015-01-01
The stochastic thermodynamics of a dilute, well-stirred mixture of chemically-reacting species is built on the stochastic trajectories of reaction events obtained from the Chemical Master Equation. However, when the molecular populations are large, the discrete Chemical Master Equation can be approximated with a continuous diffusion process, like the Chemical Langevin Equation or Low Noise Approximation. In this paper, we investigate to what extent these diffusion approximations inherit the stochastic thermodynamics of the Chemical Master Equation. We find that a stochastic-thermodynamic description is only valid at a detailed-balanced, equilibrium steady state. Away from equilibrium, where there is no consistent stochastic thermodynamics, we show that one can still use the diffusive solutions to approximate the underlying thermodynamics of the Chemical Master Equation.
How Accurate are the Gaussian and Gamma Approximations to the Outage Capacity of MIMO Channels ?
ien, Geir E.
How Accurate are the Gaussian and Gamma Approximations to the Outage Capacity of MIMO Channels MIMO capacity complementary cumulative distribution functions, or equivalently, the outage capacity distribution function (CDF) (also known as the outage capacity), or equivalently, the capacity complementary
Error Analysis of Free Probability Approximations to the Density of States of Disordered Systems
Chen, Jiahao
Theoretical studies of localization, anomalous diffusion and ergodicity breaking require solving the electronic structure of disordered systems. We use free probability to approximate the ensemble-averaged density of states ...
Weighted Radon transforms for which the Chang approximate inversion formula is precise
Roman Novikov
2011-01-17
We describe all weighted Radon transforms on the plane for which the Chang approximate inversion formula is precise. Some subsequent results, including the Cormack type inversion for these transforms, are also given.
The development of an approximate dynamic analysis of insulating glass units
Sequeira, Miguel Angel
1995-01-01
The goal of this thesis is to develop an approximate dynamic analysis of sealed insulating glass (IG) units subject to uniform blast loads, the formulation of which will be incorporated into a computer program that will ...
Approximations to wave propagation through doubly-periodic arrays of scatterers
periodic media in many physical contexts that include acoustics, elasticity, electromagnetic theory fluid. The fundamental assumptions behind these approximations are that kL 1 and a/L 1 (and hence ka 1
Efficient and private distance approximation in the communication and streaming models
Woodruff, David Paul, 1980-
2007-01-01
This thesis studies distance approximation in two closely related models - the streaming model and the two-party communication model. In the streaming model, a massive data stream is presented in an arbitrary order to a ...
Comparison of an exact analytic second born term with its asymptotic approximations
Fitzpatrick, Mathew Jared
1995-01-01
I compare atomic excitation cross sections obtained from analytic approximations with results of an exactly soluble model. The model examined is the collision of a particle interacting via a short range potential with a heavy nucleus and its...
NUMERICAL ANALYSIS OF A FINITE ELEMENT SCHEME FOR THE APPROXIMATION OF HARMONIC MAPS INTO SURFACES
Bartels, Soeren
NUMERICAL ANALYSIS OF A FINITE ELEMENT SCHEME FOR THE APPROXIMATION OF HARMONIC MAPS INTO SURFACES Geometric partial differential equations and their analysis as well as numerical simulation have recently
Torquato, Salvatore
Matrix laminate composites: Realizable approximations for the effective moduli of piezoelectric of dispersions called matrix laminates composites that are known to possess extremal elastic and dielectric performance characteristics com- pared to the pure piezoelectric ceramic. Often composites are the only
Gu, M; Li, X S; Vassilevski, P S
2010-03-16
For a given symmetric positive definite matrix A {element_of} R{sup N x N}, we develop a fast and backward stable algorithm to approximate A by a symmetric positive-definite semi-separable matrix, accurate to a constant multiple of any prescribed tolerance. In addition, this algorithm preserves the product, AZ, for a given matrix Z {element_of} R{sup N x d}, where d << N. Our algorithm guarantees the positive-definiteness of the semi-separable matrix by embedding an approximation strategy inside a Cholesky factorization procedure to ensure that the Schur complements during the Cholesky factorization all remain positive definite after approximation. It uses a robust direction-preserving approximation scheme to ensure the preservation of AZ. We present numerical experiments and discuss potential implications of our work.
Gu, Ming; Li, Xiaoye Sherry; Vassilevski, Panayot S.
2009-10-20
For a given symmetric positive definite matrix A {element_of} R{sup nxn}, we develop a fast and backward stable algorithm to approximate A by a symmetric positive-definite semi-separable matrix, accurate to any prescribed tolerance. In addition, this algorithm preserves the product, AZ, for a given matrix Z {element_of} R{sup nxd}, where d << n. Our algorithm guarantees the positive-definiteness of the semi-separable matrix by embedding an approximation strategy inside a Cholesky factorization procedure to ensure that the Schur complements during the Cholesky factorization all remain positive definite after approximation. It uses a robust direction-preserving approximation scheme to ensure the preservation of AZ. We present numerical experiments and discuss potential implications of our work.
L. W. Yeh; G. T. Chen; H. K. Chang
2006-12-22
To derive physical properties of the neutron star surface with observed spectra, a realistic model spectrum of neutron star surface emission is essential. Limited by computing resources, a full computation of the radiative transfer equations without the diffusion approximation has been conducted up to date only for the case of local magnetic fields being perpendicular to the stellar surface. In this paper we report the full-computation result for an arbitrary field direction. For comparison we also compute the radiative transfer equation using the diffusion approximation. For a given effective temperature, the computed spectrum with the diffusion approximation is always softer than that of a full computation at a non-negligible level. It leads to an over-estimate of the effective temperature if the diffusion approximation spectrum is employed in the spectral fitting. Other characteristics for different magnetic field orientations, such as the beaming pattern of the two polarization modes and the structure of the atmosphere, are also discussed.
Protein folding and phylogenetic tree reconstruction using stochastic approximation Monte Carlo
Cheon, Sooyoung
2007-09-17
Recently, the stochastic approximation Monte Carlo algorithm has been proposed by Liang et al. (2005) as a general-purpose stochastic optimization and simulation algorithm. An annealing version of this algorithm was developed for real small protein...
The Casimir Energy for a Hyperboloid Facing a Plate in the Optical Approximation
O. Schroeder; A. Scardicchio; R. L. Jaffe
2005-07-21
We study the Casimir energy of a massless scalar field that obeys Dirichlet boundary conditions on a hyperboloid facing a plate. We use the optical approximation including the first six reflections and compare the results with the predictions of the proximity force approximation and the semi-classical method. We also consider finite size effects by contrasting the infinite with a finite plate. We find sizable and qualitative differences between the new optical method and the more traditional approaches.
Moist processes and the quasi-hydrostatic approximation in a mesoscale numerical model
Kennedy, Charles Joseph
1987-01-01
MOIST PROCESSES AND THE QUASI-HYDROSTATIC APPROXIMATION IN A MESOSCALE NUMERICAL MODEL A Thesis by CHARLES JOSEPH KENNEDY Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE December 1987 Major Subject: Meteorology MOIST PROCESSES AND THE QUASI-HYDROSTATIC APPROXIMATION IN A MESOSCALE NUMERICAL MODEL A Thesis by CHARLES JOSEPH KENNEDY Approved as to style and content by: Dusan Djuric (Chair...
Dominic J. O'. Lee
2015-04-17
Presented here, is a technical manuscript that may form the basis of later published work. In it, we develop a statistical mechanical model to describe a closed loop plectoneme, applicable for when the closed loop is sufficiently supercoiled. The model divides the system up into end loops and a braided section; the end loops are assumed to contribute little to the super-coil writhe. Within the braided section, the model incorporates interactions that depend on the structure of the molecule; in particular, we consider those that depend on helical structure. A method for approximating the steric interactions is utilized that we had previously used in other publications. We go on to construct variational approximations for our closed loop plectoneme model in two cases. The first case is where helix dependent interactions are strong, and in the second case they are considered weak. In developing these approximations, we approximate the Fuller-White condition by replacing, in all expressions that depend on twist, writhe with average writhe, valid when the braided section is sufficiently long. How this approximation is made and the conditions when this approximation is valid are also discussed. The approximation allows for a Legendre transformation of the free energy, which with the introduction of moment (or torque), effectively allowing for twist and average writhe to be treated independently in the transformed (Gibbs like) free energy. Next, we then show how one may compute the average writhe of the braided section. Lastly, we discuss how some of the approximations considered may be relaxed, and discuss how the resulting model free energy might be computed by MC simulation.
Approximation of the determinant of large sparse symmetric positive definite matrices
Arnold Reusken
2000-08-10
This paper is concerned with the problem of approximating the determinant of A for a large sparse symmetric positive definite matrix A. It is shown that an efficient solution of this problem is obtained by using a sparse approximate inverse of A. The method is explained and theoretical properties are discussed. A posteriori error estimation techniques are presented. Furthermore, results of numerical experiments are given which illustrate the performance of this new method.
Approximate l-fold cross-validation with Least Squares SVM and Kernel Ridge Regression
Edwards, Richard E [ORNL] [ORNL; Zhang, Hao [ORNL] [ORNL; Parker, Lynne Edwards [ORNL] [ORNL; New, Joshua Ryan [ORNL] [ORNL
2013-01-01
Kernel methods have difficulties scaling to large modern data sets. The scalability issues are based on computational and memory requirements for working with a large matrix. These requirements have been addressed over the years by using low-rank kernel approximations or by improving the solvers scalability. However, Least Squares Support VectorMachines (LS-SVM), a popular SVM variant, and Kernel Ridge Regression still have several scalability issues. In particular, the O(n^3) computational complexity for solving a single model, and the overall computational complexity associated with tuning hyperparameters are still major problems. We address these problems by introducing an O(n log n) approximate l-fold cross-validation method that uses a multi-level circulant matrix to approximate the kernel. In addition, we prove our algorithm s computational complexity and present empirical runtimes on data sets with approximately 1 million data points. We also validate our approximate method s effectiveness at selecting hyperparameters on real world and standard benchmark data sets. Lastly, we provide experimental results on using a multi-level circulant kernel approximation to solve LS-SVM problems with hyperparameters selected using our method.
Pusa, M.; Leppaenen, J.
2012-07-01
The Chebyshev Rational Approximation Method (CRAM) has been recently introduced by the authors for solving the burnup equations with excellent results. This method has been shown to be capable of simultaneously solving an entire burnup system with thousands of nuclides both accurately and efficiently. The method was prompted by an analysis of the spectral properties of burnup matrices and it can be characterized as the best rational approximation on the negative real axis. The coefficients of the rational approximation are fixed and have been reported for various approximation orders. In addition to these coefficients, implementing the method only requires a linear solver. This paper describes an efficient method for solving the linear systems associated with the CRAM approximation. The introduced direct method is based on sparse Gaussian elimination where the sparsity pattern of the resulting upper triangular matrix is determined before the numerical elimination phase. The stability of the proposed Gaussian elimination method is discussed based on considering the numerical properties of burnup matrices. Suitable algorithms are presented for computing the symbolic factorization and numerical elimination in order to facilitate the implementation of CRAM and its adoption into routine use. The accuracy and efficiency of the described technique are demonstrated by computing the CRAM approximations for a large test case with over 1600 nuclides. (authors)
2014 Annual Workforce Analysis and Staffing Plan Report - Portsmouth
Office of Environmental Management (EM)
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2013 Annual Workforce Analysis and Staffing Plan Report - Livermore Field
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Microsoft Word - DOE_Staffing_Study_Cover.doc
Office of Environmental Management (EM)
to contractors. An analysis of the appropriate roles and responsibilities within these functions to be performed by federal and contractor personnel is currently being...
Multiple roles for the zebrafish transcriptional activator SBF/Staf
Halbig, Kari Michele
2009-05-15
Eukaryotic transcriptional activators stimulate transcription of genes otherwise expressed at low levels. The typical activator operates by binding to specific sites on DNA with its activating region contacting the ...
2012 Annual Workforce Analysis and Staffing Plan Report - Carlsbad
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
, NA-SH-40 * ED J. Yarrington, HS-10 ED G. Basabilvazo, CBFO ED A. Cooper, CBFO ED J. Waters, CBFO ED DOE M&RC *ED denotes electronic distribution Annual Workforce Analysis and...
2014 Annual Workforce Analysis and Staffing Plan Report - DOE...
Office of Environmental Management (EM)
Maintenance Mgt 0.2 0.2 Fire Protection Engineering 0.7 0.7 Performed by SSO individual. Industrial Hygiene 2 2 Page 2 of3 ATTACHMENT J Instrumentation & Control 0.2' 0.2...
2010 Annual Workforce Analysis and Staffing Plan Report - PNSO
Office of Environmental Management (EM)
Fire Protection Engineering 0.1 0.1 Fire Protection SME support is being provided by CH. Industrial Hygiene 0.33 0.33 Provided by PNSO witfa as needed support from CH....
2011 Annual Workforce Analysis and Staffing Plan Report - ORP
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to Systems Safety Oversight (SSO) Fire Protection Engineering l l Unchanged from 20 l 0 Industrial Hygiene 2 2 Unchanged from 2010 Instrumentation & Control 2 l 1 WTP Software...
2010 Annual Workforce Analysis and Staffing Plan Report - PPPO
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as Authority Having Jurisdiction. Additional support provided from EM, ORO, and EMCBC. Industrial Hygiene 0 2 Serve in collateral capacity Instrumentation and Control 0 0...
2011 Annual Workforce Analysis and Staffing Plan Report - PPPO
Office of Environmental Management (EM)
Engineering 0 0 When necessary, additional support is provided from EM, ORO, and EMCBC. Industrial Hygiene 0 0 Instrumentation and Control 0 0 Mechanical Systems 0 0 Nuclear...
Funding and Federal Staffing Requirements Funding Summary (Energy Supply)
Buildings Zero Energy Building Design . . . . . 1,367 8,000 4,000 -4,000 -50.0% Total, Zero-Energy Buildings Energy . . . . . . . . . . . . . 38,211 44,000 41,600 -2,400 -5.5% Energy Supply Energy Efficiency Efficiency and Renewable Energy Executive Summary FY 2004 Congressional Budget #12;(dollars in thousands
Microsoft Word - DOE_Staffing_Study_Cover.doc | Department of...
Office of Environmental Management (EM)
Word - DOEStaffingStudyCover.doc More Documents & Publications 2010 DOE Strategic Sustainability Performance Plan - Report to the White House Council on Environmental...
Producing Precarity: The Temporary Staffing Agency in the Labor Market
Elcioglu, Emine Fidan
2010-01-01
unpredictable temporary gigs and despite their constrainedneed to locate a server for a gig this evening.They urgehim for not showing up at a gig. Where were you, bro?You
Parameter Shortest Path Algorithms with an Application to Cyclic Staffing
Karp, Richard M.
Let G = (V,E) be a digraph with n vertices including a special vertex s. Let E' C E be a designated subset of edges. For each e E E there is an associated real number fl(e). Furthermore, let 1 if e E E' f2(e): 0 if e E-E' ...
Staffing and Placement - DOE Directives, Delegations, and Requirements
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Safety System Oversight Staffing Analysis (Instructions, Blank Sheet and
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Safety System Oversight Staffing Analysis - Example | Department of Energy
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Site Office Safety System Oversight Staffing Plan - Blank
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Staffing Guide for Project Management - DOE Directives, Delegations, and
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2013 Annual Workforce Analysis and Staffing Plan Report - Carlsbad Field
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2013 Workforce Analysis and Staffing Plan Report Memo, Guidance and
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Safety System Oversight Staffing Analysis - Blank Sheet | Department of
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2010 Annual Workforce Analysis and Staffing Plan Report - Carlsbad Field
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2011 Annual Workforce Analysis and Staffing Plan Report - Carlsbad
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DOE Executive Staffing and Recruitment | Department of Energy
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2010 Annual Workforce Analysis and Staffing Plan Report - Portsmouth
Broader source: Energy.gov (indexed) [DOE]
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2010 Workforce Analysis and Staffing Plan Report Memo, Guidance and
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2011 Workforce Analysis and Staffing Plan Report Memo, Guidance and
Broader source: Energy.gov (indexed) [DOE]
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2012 Annual Workforce Analysis and Staffing Plan Report - Carlsbad Field
Broader source: Energy.gov (indexed) [DOE]
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2012 Annual Workforce Analysis and Staffing Plan Report - Livermore Field
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2012 Annual Workforce Analysis and Staffing Plan Report - NNSA HQ |
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2012 Workforce Analysis and Staffing Plan Report Memo, Guidance and
Broader source: Energy.gov (indexed) [DOE]
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2013 Annual Workforce Analysis and Staffing Plan Report - Livermore Field
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2013 Annual Workforce Analysis and Staffing Plan Report - NNSA Production
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2014 Annual Workforce Analysis and Staffing Plan Report - Livermore Field
Broader source: Energy.gov (indexed) [DOE]
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2014 Annual Workforce Analysis and Staffing Plan Report - Nevada Field
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2014 Annual Workforce Analysis and Staffing Plan Report - Richland
Broader source: Energy.gov (indexed) [DOE]
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2014 Annual Workforce Analysis and Staffing Plan Report - Sandia Field
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2014 Workforce Analysis and Staffing Plan Report Memo, Guidance and
Broader source: Energy.gov (indexed) [DOE]
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2015 Workforce Analysis and Staffing Plan Report Memo, Guidance and
Broader source: Energy.gov (indexed) [DOE]
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Policy Guidance Memorandum #36 SES Competitive Staffing Procedures |
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2011 Annual Workforce Analysis and Staffing Plan Report - Carlsbad Field
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2012 Annual Workforce Analysis and Staffing Plan Report - Nevada Site
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2014 Annual Workforce Analysis and Staffing Plan Report - Carlsbad Field
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
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Noise kernel for a quantum field in Schwarzschild spacetime under the Gaussian approximation
A. Eftekharzadeh; Jason D. Bates; Albert Roura; Paul R. Anderson; B. L. Hu
2011-10-31
A method is given to compute an approximation to the noise kernel, defined as the symmetrized connected 2-point function of the stress tensor, for the conformally invariant scalar field in any spacetime conformal to an ultra-static spacetime for the case in which the field is in a thermal state at an arbitrary temperature. The most useful applications of the method are flat space where the approximation is exact and Schwarzschild spacetime where the approximation is better than it is in most other spacetimes. The two points are assumed to be separated in a timelike or spacelike direction. The method involves the use of a Gaussian approximation which is of the same type as that used by Page to compute an approximate form of the stress tensor for this field in Schwarzschild spacetime. All components of the noise kernel have been computed exactly for hot flat space and one component is explicitly displayed. Several components have also been computed for Schwarzschild spacetime and again one component is explicitly displayed.
Stress-energy tensor in colliding plane wave space-times: An approximation procedure
Miquel Dorca
1997-11-07
In a recent work on the quantization of a massless scalar field in a particular colliding plane wave space-time, we computed the vacuum expectation value of the stress-energy tensor on the physical state which corresponds to the Minkowski vacuum before the collision of the waves. We did such a calculation in a region close to both the Killing-Cauchy horizon and the folding singularities that such a space-time contains. In the present paper, we give a suitable approximation procedure to compute this expectation value, in the conformal coupling case, throughout the causal past of the center of the collision. This will allow us to approximately study the evolution of such an expectation value from the beginning of the collision until the formation of the Killing-Cauchy horizon. We start with a null expectation value before the arrival of the waves, which then acquires nonzero values at the beginning of the collision and grows unbounded towards the Killing-Cauchy horizon. The value near the horizon is compatible with our previous result, which means that such an approximation may be applied to other colliding plane wave space-times. Even with this approximation, the initial modes propagated into the interaction region contain a function which cannot be calculated exactly and to ensure the correct regularization of the stress-energy tensor with the point-splitting technique, this function must be given up to adiabatic order four of approximation.
Brett, Tobias Galla, Tobias
2014-03-28
We present a heuristic derivation of Gaussian approximations for stochastic chemical reaction systems with distributed delay. In particular, we derive the corresponding chemical Langevin equation. Due to the non-Markovian character of the underlying dynamics, these equations are integro-differential equations, and the noise in the Gaussian approximation is coloured. Following on from the chemical Langevin equation, a further reduction leads to the linear-noise approximation. We apply the formalism to a delay variant of the celebrated Brusselator model, and show how it can be used to characterise noise-driven quasi-cycles, as well as noise-triggered spiking. We find surprisingly intricate dependence of the typical frequency of quasi-cycles on the delay period.
S. M. Abrarov; B. M. Quine
2015-11-03
This paper presents a new approach in application of the Fourier transform to the complex error function resulting in an efficient rational approximation. Specifically, the computational test shows that with only $17$ summation terms the obtained rational approximation of the complex error function provides accuracy ${10^{ - 15}}$ over the most domain of practical importance $0 \\le x \\le 40,000$ and ${10^{ - 4}} \\le y \\le {10^2}$ required for the HITRAN-based spectroscopic applications. Since the rational approximation does not contain trigonometric or exponential functions dependent upon the input parameters $x$ and $y$, it is rapid in computation. Such an example demonstrates that the considered methodology of the Fourier transform may be advantageous in practical applications.
Collective Modes in a Superfluid Neutron Gas within the Quasiparticle Random-Phase Approximation
Nol Martin; Michael Urban
2015-01-05
We study collective excitations in a superfluid neutron gas at zero temperature within the quasiparticle random phase approximation. The particle-hole residual interaction is obtained from a Skyrme functional, while a separable interaction is used in the pairing channel which gives a realistic density dependence of the pairing gap. In accordance with the Goldstone theorem, we find an ungapped collective mode (analogous to the Bogoliubov-Anderson mode). At low momentum, its dispersion relation is approximately linear and its slope coincides with the hydrodynamic speed of sound calculated with the Skyrme equation of state. The response functions are compared with those obtained within the Landau approximation. We also compute the contribution of the collective mode to the specific heat of the neutron gas, which is relevant for the thermodynamic properties of the inner crust of neutron stars.
An improved approximation scheme for the centrifugal term and the Hulthen potential
Sameer M. Ikhdair
2009-01-07
We present a new approximation scheme for the centrifugal term to solve the Schrodinger equation with the Hulthen potential for any arbitrary l state by means of a mathematical Nikiforov-Uvarov (NU) method. We obtain the bound state energy eigenvalues and the normalized corresponding eigenfunctions expressed in terms of the Jacobi polynomials or hypergeometric functions for a particle exposed to this potential field. Our numerical results of the energy eigenvalues are found to be in high agreement with those results obtained by using the program based on a numerical integration procedure. The s-wave (l=0) analytic solution for the binding energies and eigenfunctions of a particle are also calculated. The physical meaning of the approximate analytical solution is discussed. The present approximation scheme is systematic and accurate.
Vladimir Maz'ya; Alexander Movchan; Michael Nieves
2010-05-24
We describe a method of asymptotic approximations to solutions of mixed boundary value problems for the Laplacian in a three-dimensional domain with many perforations of arbitrary shape, with the Neumann boundary conditions being prescribed on the surfaces of small voids. The only assumption made on the geometry is that the diameter of a void is assumed to be smaller compared to the distance to the nearest neighbour. The asymptotic approximation, obtained here, involves a linear combination of dipole fields constructed for individual voids, with the coefficients, which are determined by solving a linear algebraic system. We prove the solvability of this system and derive an estimate for its solution. The energy estimate is obtained for the remainder term of the asymptotic approximation.
Simulating higher-dimensional geometries in GADRAS using approximate one-dimensional solutions.
Thoreson, Gregory G.; Mitchell, Dean James; Harding, Lee T.
2013-02-01
The Gamma Detector Response and Analysis Software (GADRAS) software package is capable of simulating the radiation transport physics for one-dimensional models. Spherical shells are naturally one-dimensional, and have been the focus of development and benchmarking. However, some objects are not spherical in shape, such as cylinders and boxes. These are not one-dimensional. Simulating the radiation transport in two or three dimensions is unattractive because of the extra computation time required. To maintain computational efficiency, higher-dimensional geometries require approximations to simulate them in one-dimension. This report summarizes the theory behind these approximations, tests the theory against other simulations, and compares the results to experimental data. Based on the results, it is recommended that GADRAS users always attempt to approximate reality using spherical shells. However, if fissile material is present, it is imperative that the shape of the one-dimensional model matches the fissile material, including the use of slab and cylinder geometry.
Relativistic equation of state at subnuclear densities in the Thomas-Fermi approximation
Zhang, Z. W.; Shen, H., E-mail: shennankai@gmail.com [School of Physics, Nankai University, Tianjin 300071 (China)
2014-06-20
We study the non-uniform nuclear matter using the self-consistent Thomas-Fermi approximation with a relativistic mean-field model. The non-uniform matter is assumed to be composed of a lattice of heavy nuclei surrounded by dripped nucleons. At each temperature T, proton fraction Y{sub p} , and baryon mass density ? {sub B}, we determine the thermodynamically favored state by minimizing the free energy with respect to the radius of the Wigner-Seitz cell, while the nucleon distribution in the cell can be determined self-consistently in the Thomas-Fermi approximation. A detailed comparison is made between the present results and previous calculations in the Thomas-Fermi approximation with a parameterized nucleon distribution that has been adopted in the widely used Shen equation of state.
Maz'ya, Vladimir; Nieves, Michael
2010-01-01
We describe a method of asymptotic approximations to solutions of mixed boundary value problems for the Laplacian in a three-dimensional domain with many perforations of arbitrary shape, with the Neumann boundary conditions being prescribed on the surfaces of small voids. The only assumption made on the geometry is that the diameter of a void is assumed to be smaller compared to the distance to the nearest neighbour. The asymptotic approximation, obtained here, involves a linear combination of dipole fields constructed for individual voids, with the coefficients, which are determined by solving a linear algebraic system. We prove the solvability of this system and derive an estimate for its solution. The energy estimate is obtained for the remainder term of the asymptotic approximation.
APPROXIMATION ON NASH SETS WITH MONOMIAL SINGULARITIES (joint work with J.F. Fernando and J.M. Ruiz)
Baro, Elas
APPROXIMATION ON NASH SETS WITH MONOMIAL SINGULARITIES Elas Baro (joint work with J.F. Fernando and J.M. Ruiz) Universidad Complutense de Madrid APPROXIMATION ON NASH SETS WITH MONOMIAL SINGULARITIES and definitions This work is devoted to the approximation of differentiable semialgebraic functions by Nash
Experimental demonstration of error-insensitive approximate universal-NOT gates
Sang Min Lee; Jeongho Bang; Heonoh Kim; Hyunseok Jeong; Jinhyoung Lee; Han Seb Moon
2014-03-17
We propose and experimentally demonstrate an approximate universal-NOT (U-NOT) operation that is robust against operational errors. In our proposal, the U-NOT operation is composed of stochastic unitary operations represented by the vertices of regular polyhedrons. The operation is designed to be robust against random operational errors by increasing the number of unitary operations (i.e., reference axes). Remarkably, no increase in the total number of measurements nor additional resources are required to perform the U-NOT operation. Our method can be applied in general to reduce operational errors to an arbitrary degree of precision when approximating any anti-unitary operation in a stochastic manner.
Analysis of finite element approximation and iterative methods for time-dependent Maxwell problems
Zhao, Jun
2004-09-30
naturally transfer (2.20) to the semi-discrete scheme of seeking (Eh(t);Bh(t)) in Uh Vh satisfying, for any 0 Eh;t;uh) ( 1Bh;curluh) = (J;uh); for all uh 2 Uh; ( 1Bh;t;vh) + (curlEh; 1vh) = 0; for all vh 2 Vh; (2.21) 19 with given initial... approximations Eh(0) E0 and Eh(0) E0: (2.22) We will discuss possible choices of initial approximations in the following chapter. When we try to discretize time derivatives in (2.21), the stability of the resulting fully discrete scheme critically depends...
On the approximations of the distribution function of fusion alpha particles
Bilato, R. Brambilla, M.; Poli, E.
2014-10-15
The solution of the drift-kinetic equation for fusion-born alpha particles is derived in the limit of dominant parallel streaming, and it is related to the usual slowing-down distribution function. The typical approximations of the fast tail of fusion-born alpha particles are briefly compared and discussed. In particular, approximating the distribution function of fast-alpha particles with an equivalent Maxwellian is inaccurate to describe absorption of radio-frequency waves in the ion-cyclotron range of frequencies.
Fiat, Amos
Approximate Pure Nash Equilibria in Weighted Congestion Games: Existence, Efficient Computation and algorithmic questions related to the Nash dynamics of weighted congestion games. In weighted congestion games with linear latency functions, the existence of pure Nash equilibria is guaranteed by potential function
Approximate Response Time for Fixed Priority Real-Time Systems with Energy-Harvesting
Boyer, Edmond
Approximate Response Time for Fixed Priority Real-Time Systems with Energy-Harvesting Yasmina constraints. In this problem, energy is harvested from the ambient environment and used to replenish a storage on whether their rate of energy consumption is (i) more than or (ii) no more than the storage unit
Buffer Sizing for Minimum Energy-Delay Product by Using an Approximating Polynomial
Pedram, Massoud
Buffer Sizing for Minimum Energy-Delay Product by Using an Approximating Polynomial Chang Woo Kang to derive sizing rules for buffered chains, which optimize the overall energy-delay product. Categories result in a poor solution in terms of the energy-delay product. The focus of this work is on multi
International Association for Cryptologic Research (IACR)
Analysis of ARX Functions: Pseudo-linear Methods for Approximation, Differentials, and Evaluating for substitution box table lookups. Computing the non-linear function in memory is also a means of defense against , where 1 w n, in ARX functions that use large words (e.g., 32-bit words or 64-bit words). Three main
Miller, William H.
of linearization of the general SC-IVR expression for the reactive flux correlation function (which is related10ARTICLES Generalization of the Linearized Approximation to the Semiclassical Initial Value Representation for Reactive Flux Correlation Functions William H. Miller Department of Chemistry, Uni
Fast Gradient-Descent Methods for Temporal-Difference Learning with Linear Function Approximation
Szepesvari, Csaba
Fast Gradient-Descent Methods for Temporal-Difference Learning with Linear Function Approximation with both linear function ap- proximation and off-policy training, and whose complexity scales only linearly requirements. 1. Motivation Temporal-difference methods based on gradient descent and linear function
Parr, Ronald
An Analysis of Linear Models, Linear Value-Function Approximation, and Feature Selection, Piscataway, NJ 08854 USA Abstract We show that linear value-function approxima- tion is equivalent to a form trees, neural networks, and linear functions. The first contribution of this paper shows that, when
Approximation-Tolerant Model-Based Compressive Sensing Chinmay Hegde, Piotr Indyk, Ludwig Schmidt
Approximation-Tolerant Model-Based Compressive Sensing Chinmay Hegde, Piotr Indyk, Ludwig Schmidt the measurement process. Standard results in compressive sensing show that it is possible to recover the signal x compressive sensing [BCDH10] overcomes the lower bound and reduces the number of measurements further to O
A New 2D-Transport, 1D-Diffusion Approximation of the Boltzmann Transport equation
Larsen, Edward
2013-06-17
The work performed in this project consisted of the derivation, implementation, and testing of a new, computationally advantageous approximation to the 3D Boltz- mann transport equation. The solution of the Boltzmann equation is the neutron flux in nuclear reactor cores and shields, but solving this equation is difficult and costly. The new 2D/1D approximation takes advantage of a special geometric feature of typical 3D reactors to approximate the neutron transport physics in a specific (ax- ial) direction, but not in the other two (radial) directions. The resulting equation is much less expensive to solve computationally, and its solutions are expected to be sufficiently accurate for many practical problems. In this project we formulated the new equation, discretized it using standard methods, developed a stable itera- tion scheme for solving the equation, implemented the new numerical scheme in the MPACT code, and tested the method on several realistic problems. All the hoped- for features of this new approximation were seen. For large, difficult problems, the resulting 2D/1D solution is highly accurate, and is calculated about 100 times faster than a 3D discrete ordinates simulation.
An Approximate Method to Assess the Peaking Capability of the NW Hydroelectric System
DRAFT 1 An Approximate Method to Assess the Peaking Capability of the NW Hydroelectric System September 26, 2005 The best way to assess the hydroelectric system's peaking capability is to simulate its. This model simulates the operation of the major hydroelectric projects over a one-week (168 hour) period
Power and Effective Study Size Based on Approximations to the Expected Likelihood Ratio
Washington at Seattle, University of
Power and Effective Study Size Based on Approximations to the Expected Likelihood Ratio Test statistical power and precision of heritability estimates can be difficult particularly in complex pedigrees. Previous work focused on the power to detect heritability by using the expectation of the likelihood ratio
A new method for deriving waiting-time approximations in polling systems with renewal arrivals
van der Mei, Rob
. The most general results known for renewal-driven polling models are asymp- totic results, such as heavy models with renewal arrivals. Motivated by this, in this paper we propose a new method for derivingA new method for deriving waiting-time approximations in polling systems with renewal arrivals J
The Exemplar Breakpoint Distance for Non-trivial Genomes Cannot Be Approximated
Blin, Guillaume
The Exemplar Breakpoint Distance for Non-trivial Genomes Cannot Be Approximated Guillaume Blin1 - France guillaume.fertin@univ-nantes.fr Abstract. A promising and active field of comparative genomics con- sists in comparing two genomes by establishing a one-to-one correspon- dence (i.e., a matching) between
Finite Element Approximation of the Acoustic Wave Equation: Error Control and Mesh
Bangerth, Wolfgang
Finite Element Approximation of the Acoustic Wave Equation: Error Control and Mesh Adaptation of the Acoustic Wave Equation: Error Control and Mesh Adaptation Wolfgang Bangerth and Rolf Rannacher1 Institute@iwr.uni-heidelberg.de Abstract We present an approach to solving the acoustic wave equation by adaptive finite el- ement methods
Gibbons, Phillip B.
optimizer to estimate plan costs; such an application demands very fast response times but not exact answers to provide fast, approximate answers to complex aggregate queries based on statistical summaries of the full solely on providing exact answers to queries, in a manner that seeks to minimize response time
Weighted Radon transforms for which the Chang approximate inversion formula is precise
Paris-Sud XI, Universit de
Weighted Radon transforms for which the Chang approximate inversion formula is precise R.G. Novikov formula is precise. Some subsequent results, including the Cormack type inversion for these transforms, are also given. 1.Introduction We consider the weighted ray transformation PW defined by the formula PW f
Approximate Dynamic Programming With Correlated Bayesian Beliefs Ilya O. Ryzhov and Warren B. Powell
Powell, Warren B.
, consider an energy storage problem in which the spot price of energy is modeled using a stochastic and Financial Engineering, Princeton University, Princeton, NJ (email: {iryzhov,powell}@princeton.edu). using external process or via simulation. A fundamental problem of approximate dynamic program- ming is known
Strategie s for Walking on Potential Energy Surfaces Using Local Quadratic Approximations
Simons, Jack
Strategie s for Walking on Potential Energy Surfaces Using Local Quadratic Approximations JACK on potential energy surfaces is further analyzed. This method utilizes local gradient and Hessian (Le., fust and second energy derivative) information to generate a series of "steps" that are folIowed to the desired
Approximation Algorithms For Wireless Sensor Deployment Xiaochun Xu and Sartaj Sahni
Sahni, Sartaj K.
will be able to adequately monitor the target region. When site selection is possible, we use deterministic of the problem considered here is in the deployment of chemical and radioactive sensors so as to monitor high risk targets that may be approximated as points; the cost of a sensor may be from hundreds of dollars
Interior-point method for nuclear norm approximation with application to system identification
Vandenberghe, Lieven
Interior-point method for nuclear norm approximation with application to system identification Zhang Liu and Lieven Vandenberghe Abstract The nuclear norm (sum of singular values) of a matrix minimization and sparse signal estimation. In this paper we consider the problem of minimizing the nuclear norm
Abstract This study compares approximately weekly soil respiration across two forestpasture
Beltrami, Hugo
carbon budget. Soils are the largest source of non-anthropogenic CO2 and hold approximately twice respiration it is impor- tant to quantify changes in soil CO2 emissions associated with shifts in vegetation with similar soil, topography and climate to document how conversion of pasture to forest alters net soil CO2
Some approximate Godunov schemes to compute shallow-water equations with topography
Gallout, Thierry
Some approximate Godunov schemes to compute shallow-water equations with topography Thierry the computation of shallow-water equations with topography by Finite Volume methods, in a one are based on a discretisation of the topography by a piecewise function constant on each cell of the mesh
Regier, Terry
Numeral systems across languages support efficient communication: From approximate numerosity this spectrum. We find that these numeral systems all reflect a functional need for efficient communication differ qualitatively in their numeral systems. At one extreme, some languages have a small set of number
Neutrinoless double beta decay of 48Ca in the shell model: Closure versus nonclosure approximation
R. A. Sen'kov; M. Horoi
2013-12-16
Neutrinoless double-beta decay is a unique process that could reveal physics beyond the Standard Model. Essential ingredients in the analysis of neutrinoless double-beta rates are the associated nuclear matrix elements. Most of the approaches used to calculate these matrix elements rely on the closure approximation. Here we analyze the light neutrino-exchange matrix elements of 48Ca neutrinoless double-beta decay and test the closure approximation in a shell-model approach. We calculate the neutrinoless double-beta nuclear matrix elements for 48Ca using both the closure approximation and a nonclosure approach, and we estimate the uncertainties associated with the closure approximation. We demonstrate that the nonclosure approach has excellent convergence properties which allow us to avoid unmanageable computational cost. Combining the nonclosure and closure approaches we propose a new method of calculation for neutrinoless double-beta decay rates which can be applied to the neutrinoless double-beta decay rates of heavy nuclei, such as 76Ge or 82Se.
How hard can it be to pitch a wind turbine blade? Moment of inertia approximately
How hard can it be to pitch a wind turbine blade? Moment of inertia approximately as a small car (1 ton) on 7 m arm Morten Hartvig Hansen Wind Energy Department Ris, DTU #12;How hard can it be to pitch a wind turbine blade? Hydraulic pitch actuator for the virtual NREL 5 MW turbine Motivation Actuator
Green: A Framework for Supporting Energy-Conscious Programming using Controlled Approximation
Chilimbi, Trishul
/solution (QoS) for improvements in performance and reduc- tion in energy consumption. Programmers sometimes engine, indicate that Green can produce significant improvements in performance and energy consumptionGreen: A Framework for Supporting Energy-Conscious Programming using Controlled Approximation
On Resource Allocation in Fading Multiple Access Channels -An Efficient Approximate Projection
Médard, Muriel
and power allocation policies that maximize a general concave utility function of average transmission rates] consider allocation of rate and power to maximize a linear utility function of the transmission rates over1 On Resource Allocation in Fading Multiple Access Channels - An Efficient Approximate Projection
Approximating Minimum-Power Edge-Covers and 2, 3-Connectivity Guy Kortsarz
Kortsarz, Guy
than edge-connectivity, as it models stations failures. Such power minimization problems were vastlyApproximating Minimum-Power Edge-Covers and 2, 3-Connectivity Guy Kortsarz Rutgers University a graph with edge costs, the power of a node is the maximum cost of an edge leaving it, and the power
Spectrum of the hydrogen atom in Snyder space in a semiclassical approximation
B. Ivetic; S. Mignemi; A. Samsarov
2015-10-21
We study the spectrum of the hydrogen atom in Snyder space in a semiclassical approximation based on a generalization of the Born-Sommerfeld quantization rule. While the corrections to the standard quantum mechanical spectrum arise at first order in the Snyder parameter for the $l=0$ states, they are of second order for $l\
Two-dimensional Finite Larmor Radius approximation in canonical gyrokinetic coordinates
Frnod, Emmanuel
-* convergence results. 1 Introduction Nowadays, domestic energy production by using magnetic confinement fusion magnetic confinement, needed to reach nuclear fusion reaction, is a very complex phys- ical phenomenon results about the approximation of the Vlasov-Poisson system with a strong external magnetic field
Weber, J. W.; Bol, A. A. [Department of Applied Physics, Eindhoven University of Technology, Den Dolech 2, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Sanden, M. C. M. van de [Department of Applied Physics, Eindhoven University of Technology, Den Dolech 2, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Dutch Institute for Fundamental Energy Research (DIFFER), Nieuwegein (Netherlands)
2014-07-07
This work presents an improved thin film approximation to extract the optical conductivity from infrared transmittance in a simple yet accurate way. This approximation takes into account the incoherent reflections from the backside of the substrate. These reflections are shown to have a significant effect on the extracted optical conductivity and hence on derived parameters as carrier mobility and density. By excluding the backside reflections, the error for these parameters for typical chemical vapor deposited (CVD) graphene on a silicon substrate can be as high as 17% and 45% for the carrier mobility and density, respectively. For the mid- and near-infrared, the approximation can be simplified such that the real part of the optical conductivity is extracted without the need for a parameterization of the optical conductivity. This direct extraction is shown for Fourier transform infrared (FTIR) transmittance measurements of CVD graphene on silicon in the photon energy range of 3707000?cm{sup ?1}. From the real part of the optical conductivity, the carrier density, mobility, and number of graphene layers are determined but also residue, originating from the graphene transfer, is detected. FTIR transmittance analyzed with the improved thin film approximation is shown to be a non-invasive, easy, and accurate measurement and analysis method for assessing the quality of graphene and can be used for other 2-D materials.
Amand Faessler; G. L. Fogli; E. Lisi; V. Rodin; A. M. Rotunno; F. Simkovic
2009-03-06
The variances and covariances associated to the nuclear matrix elements (NME) of neutrinoless double beta decay are estimated within the quasiparticle random phase approximation (QRPA). It is shown that correlated NME uncertainties play an important role in the comparison of neutrinoless double beta decay rates for different nuclei, and that they are degenerate with the uncertainty in the reconstructed Majorana neutrino mass.
Pablo Echenique; J. L. Alonso
2006-12-04
A set of rules is defined to systematically number the groups and the atoms of organic molecules and, particularly, of polypeptides in a modular manner. Supported by this numeration, a set of internal coordinates is defined. These coordinates (termed Systematic, Approximately Separable and Modular Internal Coordinates, SASMIC) are straightforwardly written in Z-matrix form and may be directly implemented in typical Quantum Chemistry packages. A number of Perl scripts that automatically generate the Z-matrix files for polypeptides are provided as supplementary material. The main difference with other Z-matrix-like coordinates normally used in the literature is that normal dihedral angles (``principal dihedrals'' in this work) are only used to fix the orientation of whole groups and a somewhat non-standard type of dihedrals, termed ``phase dihedrals'', are used to describe the covalent structure inside the groups. This physical approach allows to approximately separate soft and hard movements of the molecule using only topological information and to directly implement constraints. As an application, we use the coordinates defined and ab initio quantum mechanical calculations to assess the commonly assumed approximation of the free energy, obtained from ``integrating out'' the side chain degree of freedom chi, by the Potential Energy Surface (PES) in the protected dipeptide HCO-L-Ala-NH2. We also present a sub-box of the Hessian matrix in two different sets of coordinates to illustrate the approximate separation of soft and hard movements when the coordinates defined in this work are used.
Approximate Hierarchies of Linear Control Systems Antoine Girard and George J. Pappas
Pappas, George J.
Approximate Hierarchies of Linear Control Systems Antoine Girard and George J. Pappas Abstract introduced. The proposed hierarchical control architecture consists of a precise model (the concrete system) of the plant to be controlled and of a rough model (the abstract system) of the plant that is used for control
Yaron, David
Embedding parameters in ab initio theory to develop well- controlled approximations based Journal of Chemical Theory and Computation #12;1 Embedding parameters in ab initio theory to develop well-controlled on molecular similarity Journal: Journal of Chemical Theory and Computation Manuscript ID: Draft Manuscript
Approximate Bisimulations for Nonlinear Dynamical Systems Antoine Girard and George J. Pappas
Pappas, George J.
Approximate Bisimulations for Nonlinear Dynamical Systems Antoine Girard and George J. Pappas generalization of the exact notions of bisimulation of nonlinear dynamical systems [9], [20], [22]. Furthermore nonlinear systems. This is achieved by requiring that a distance between system observations starts
A SIMPLE CLOSURE APPROXIMATION FOR SLOW DYNAMICS OF A MULTISCALE SYSTEM: NONLINEAR AND
Abramov, Rafail
A SIMPLE CLOSURE APPROXIMATION FOR SLOW DYNAMICS OF A MULTISCALE SYSTEM: NONLINEAR response, multiscale systems, nonlinear coupling AMS subject classifications. 37M, 37N 1. Introduction slow and fast variables of the system. Many closure methods were designed for multiscale dynamical
Inversion of weighted Radon transforms via finite Fourier series weight approximations
Guillement, Jean-Pol
Inversion of weighted Radon transforms via finite Fourier series weight approximations J Moscow, Russia e-mail: novikov@cmap.polytechnique.fr Abstract. We consider weighted Radon transforms approach by numerical examples for the case of the attenuated Radon transforms in the framework
1 STATIC SECTORIZATION APPROACH TO DYNAMIC AIRSPACE CONFIGURATION USING APPROXIMATE DYNAMIC to Dynamic Airspace Configuration (DAC) by static sectorization. The objective of this paper is to address the issue of static sectorization by partitioning airspace based on controller workload i.e. airspace
HYDROGEN ATOMS IN NEUTRON STAR ATMOSPHERES: ANALYTICAL APPROXIMATIONS FOR BINDING ENERGIES
HYDROGEN ATOMS IN NEUTRON STAR ATMOSPHERES: ANALYTICAL APPROXIMATIONS FOR BINDING ENERGIES Atoms energies of the hydrogen atom arbitrarily moving in a magnetic field typical of neutron stars, 300 Ÿ fl Ÿ the spectrum of outgoing thermal radiation, likely consists of hydrogen, the most abundant element
expansion about a small parameter that involves the dominant frequency of the wind forcing and the oceanic1 Ocean response to arbitrary wind perturbations in the low-frequency approximation: implications study the response of the ocean thermocline in the Pacific to arbitrary periodic wind stress
Approximate Revenue Maximization with Multiple Items SERGIU HART, Hebrew University of Jerusalem
Fiat, Amos
Approximate Revenue Maximization with Multiple Items SERGIU HART, Hebrew University of Jerusalem.1846. The work of Sergiu Hart is partially supported by a European Research Council Advanced Investigator grant and by a Google grant on Electronic Markets and Auctions. Author's addresses: Sergiu Hart, Institute
A Sparse Representation for Function Approximation 1 Tomaso Poggio and Federico Girosi
Poggio, Tomaso
A Sparse Representation for Function Approximation 1 Tomaso Poggio and Federico Girosi Center relation to PCA, regularization, sparsity principles and Support Vector Machines. 1 This paper appeared optimal locations. Our standard example throughout the paper is the regression problem of reconstructing
Katsaounis, Theodoros D.
1 Relaxation Approximations to Shallow Water and Pollutant Transport Equations A.I. Delis solution of shallow water flows and the transport and diffusion of pollutant in such flows. By first can be considered as an alternative to classical finite difference methods. Keywords--Shallow water
On the Approximation of Correlated NonGaussian Noise Pdfs using Gaussian Mixture Models
Blum, Rick
On the Approximation of Correlated NonGaussian Noise Pdfs using Gaussian Mixture Models R. S. Blum functions (pdfs) have been popular for modeling non Gaussian noise. The majority of nonGaussian noise of Gaussian mixture pdfs to model correlated nonGaussian noise processes. In this paper, we initiate
Guided GUI Testing of Android Apps with Minimal Restart and Approximate Learning
McAuliffe, Jon
Guided GUI Testing of Android Apps with Minimal Restart and Approximate Learning Wontae Choi Working Example 3 #12;W.Choi@OOPSLA'13 Working Example 3 Android app 3 consecutive EULA screens Touching No will terminate the app Scroll does nothing #12;W.Choi@OOPSLA'13 Working Example 3 Android
Fiat, Amos
Chapter 1 Approximation and Mechanism Design Our world is an interconnected collection of economic to mechanisms for exchanging goods or services that are good in terms of revenue or social benefit. The two on a combined computational and economic theory for the study and design of mechanisms. A central theme
Prior-independent Approximation In the last two chapters we discussed mechanism that performed well
Fiat, Amos
5 Prior-independent Approximation In the last two chapters we discussed mechanism that performed is natural when deriving mechanisms for games of in- complete information as the Bayes-Nash equilibrium mechanism with it. The goal of prior-independent mechanism design is to identify a single mech- anism
Numerical approximation of bang-bang controls for the heat equation: an optimal design approach
Paris-Sud XI, Universit de
Numerical approximation of bang-bang controls for the heat equation: an optimal design approach computation of null controls of minimal L -norm for the linear heat equation with a bounded potential. Both and boundary controllability cases, are described within this new approach. Keywords: Linear heat equation
Numerical approximation of null controls for the heat equation through transmutation
Sart, Remi
Numerical approximation of null controls for the heat equation through transmutation Arnaud M to the ill-posedness of the backward heat problem. The controls of minimal L2 -norm are characterized the control of a heat process in terms of the corresponding control of the associated wave process, by means
Approximating the minimum clique cover and other hard problems in subtree filament graphs
Stewart, Lorna
Approximating the minimum clique cover and other hard problems in subtree filament graphs J. Mark Keil Lorna Stewart March 20, 2006 Abstract Subtree filament graphs are the intersection graphs of subtree filaments in a tree. This class of graphs contains subtree overlap graphs, interval filament
Improved Steiner Tree Approximation in Graphs Gabriel Robins \\Lambda Alexander Zelikovsky y
Zelikovsky, Alexander
). In quasibipartite graphs our heuristic achieves an approximation ratio of 1:28 in time O(mn 2 ), where m also show \\Lambda Department of Computer Science, University of Virginia, Thornton Hall, Charlottesville, VA, 22903, robins@cs.virginia.edu y Department of Computer Science, Georgia State University
Sensitivity Analysis of a Dynamic Fleet Management Model Using Approximate Dynamic Programming
Topaloglu, Huseyin
of fleet management models is to make the vehicle repositioning and vehicle-to-load assignment decisions soSensitivity Analysis of a Dynamic Fleet Management Model Using Approximate Dynamic Programming present tractable algorithms to assess the sensitivity of a stochastic dynamic fleet management model
Approximation of Stationary Control Policies by Quantized Control in Markov Decision Processes
Yüksel, Serdar
Approximation of Stationary Control Policies by Quantized Control in Markov Decision Processes Naci quantizers are also derived. Thus, one can search for -optimal policies within quantized control policies. These pave the way for applications in optimal design of networked control systems where controller actions
Analytical approximation methods for the stabilizing solution of the Hamilton-Jacobi
Schaft, Arjan van der
1 Analytical approximation methods for the stabilizing solution of the Hamilton-Jacobi equation the stabilizing solution of the Hamilton-Jacobi equation are proposed using symplectic geometry and a Hamiltonian of the Hamilton-Jacobi equation as an integrable Hamiltonian system with a perturbation caused by control
of algorithms adapted to massively parallel computers. 1 #12; 1 Introduction The early days of global atmospheric modeling saw significant efforts in adapting then current numerical methods to solving fluid flow alternative methods of approximation for global atmospheric models. Currently there is renewed interest
Approximation Theory and Finite Element Analysis January 2014 Lecturer David Silvester
Silvester, David J.
Approximation Theory and Finite Element Analysis January 2014 Lecturer David Silvester Office Alan Analysis, CUP, 2003. Dietrich Braess, Finite Elements: Theory, Fast Solvers and Applications in Solid Mechanics, CUP, Third Edition, 2007. Howard Elman, David Silvester and Andy Wathen, Finite Elements
Physical approximations for the nonlinear evolution of perturbations in dark energy scenarios
L. R. Abramo; R. C. Batista; L. Liberato; R. Rosenfeld
2008-06-20
The abundance and distribution of collapsed objects such as galaxy clusters will become an important tool to investigate the nature of dark energy and dark matter. Number counts of very massive objects are sensitive not only to the equation of state of dark energy, which parametrizes the smooth component of its pressure, but also to the sound speed of dark energy as well, which determines the amount of pressure in inhomogeneous and collapsed structures. Since the evolution of these structures must be followed well into the nonlinear regime, and a fully relativistic framework for this regime does not exist yet, we compare two approximate schemes: the widely used spherical collapse model, and the pseudo-Newtonian approach. We show that both approximation schemes convey identical equations for the density contrast, when the pressure perturbation of dark energy is parametrized in terms of an effective sound speed. We also make a comparison of these approximate approaches to general relativity in the linearized regime, which lends some support to the approximations.
Abramo, L. R.; Batista, R. C. [Instituto de Fisica, Universidade de Sao Paulo, CP 66318, 05315-970, Sao Paulo (Brazil); Liberato, L.; Rosenfeld, R. [Instituto de Fisica Teorica, Universidade Estadual Paulista, R. Pamplona 145, 01405-900, Sao Paulo (Brazil)
2009-01-15
The abundance and distribution of collapsed objects such as galaxy clusters will become an important tool to investigate the nature of dark energy and dark matter. Number counts of very massive objects are sensitive not only to the equation of state of dark energy, which parametrizes the smooth component of its pressure, but also to the sound speed of dark energy, which determines the amount of pressure in inhomogeneous and collapsed structures. Since the evolution of these structures must be followed well into the nonlinear regime, and a fully relativistic framework for this regime does not exist yet, we compare two approximate schemes: the widely used spherical collapse model and the pseudo-Newtonian approach. We show that both approximation schemes convey identical equations for the density contrast, when the pressure perturbation of dark energy is parametrized in terms of an effective sound speed. We also make a comparison of these approximate approaches to general relativity in the linearized regime, which lends some support to the approximations.
A Fast Approximation of the Bilateral Filter using a Signal Processing Approach
Reif, Rafael
A Fast Approximation of the Bilateral Filter using a Signal Processing Approach Sylvain Paris Fr of such accelerations. In this paper, we propose a new signal-processing analysis of the bilateral filter which to the original domain dimensions. Importantly, this signal-processing perspective allows us to develop a novel
Error of the network approximation for densely packed composites with irregular geometry
Novikov, Alexei
the concentration of the filling inclusions is high is particularly relevant to polymer/ceramic composites, because a polymer matrix compensates for the brittle nature of ceramics which is their main weakness. A surveyError of the network approximation for densely packed composites with irregular geometry Leonid
A Coupled AtmosphereOcean Radiative Transfer System Using the Analytic Four-Stream Approximation
Liou, K. N.
of the ocean. Shortwave radiation from the sun contributes most of the heat fluxes that penetrate the airA Coupled AtmosphereOcean Radiative Transfer System Using the Analytic Four-Stream Approximation WEI-LIANG LEE AND K. N. LIOU Department of Atmospheric and Oceanic Sciences, University of California
Gregor Tanner; Niels Sondergaard
2006-08-17
We derive a short wave length approximation of a boundary integral operator for two-dimensional isotropic and homogeneous elastic bodies of arbitrary shape. Trace formulae for elastodynamics can be deduced in this way from first principles starting directly from Navier-Cauchy's equation.
Zhou, Zhennan
2014-09-01
In this paper, we approximate the semi-classical Schrdinger equation in the presence of electromagnetic field by the Hagedorn wave packets approach. By operator splitting, the Hamiltonian is divided into the modified part and the residual part. The modified Hamiltonian, which is the main new idea of this paper, is chosen by the fact that Hagedorn wave packets are localized both in space and momentum so that a crucial correction term is added to the truncated Hamiltonian, and is treated by evolving the parameters associated with the Hagedorn wave packets. The residual part is treated by a Galerkin approximation. We prove that, with the modified Hamiltonian only, the Hagedorn wave packets dynamics give the asymptotic solution with error O(?{sup 1/2}), where ? is the scaled Planck constant. We also prove that, the Galerkin approximation for the residual Hamiltonian can reduce the approximation error to O(?{sup k/2}), where k depends on the number of Hagedorn wave packets added to the dynamics. This approach is easy to implement, and can be naturally extended to the multidimensional cases. Unlike the high order Gaussian beam method, in which the non-constant cut-off function is necessary and some extra error is introduced, the Hagedorn wave packets approach gives a practical way to improve accuracy even when ? is not very small.
Abstract. Experimental enthalpies of formation have been approximated using single-point HartreeFock
Csonka, Gbor Istvn
Abstract. Experimental enthalpies of formation have been approximated using single-point Hartree from the G2/97 thermochem- istry database (containing small molecules) together with natural population deviations from the experimental enthalpies of formation for the selected 51 molecules are 1.15, 3.96, and 2
Maximum Entropy Solution to Ill-posed Inverse Problems with Approximately
Pelletier, Bruno
physical assumptions, the radi- ance may be related to the aerosol vertical profile by a Fredholm integral and Gassiat, 1999) and have proved useful in seismic tomography (Fermin, Loubes and Ludena, 2006) and in image of accuracy of the approximation or the order of a model. As an exemple, in remote sensing of aerosol vertical
On-line and Approximation Algorithms Fall Semester, 2011/12 Final Exam: February 8, 2012
Azar, Yossi
On-line and Approximation Algorithms Fall Semester, 2011/12 Final Exam: February 8, 2012 Lecturer a subset of machines Si of size m/2 and two values wi and pi. Assigning job i is assigned to a machine j Si increases the load of j by wi where assigning job i to a machine j / Si increases the load of j
On-line and Approximation Algorithms Fall Semester, 2009/10 Final Exam: January 25, 2010
Azar, Yossi
On-line and Approximation Algorithms Fall Semester, 2009/10 Final Exam: January 25, 2010 Lecturer capacity. At round i we receive a request to connect si to ti with one of two options. The first non additive constant is needed). The duration of the exam is 3 hours. GOOD LUCK 1 #12;
On-line and Approximation Algorithms Spring Semester, 2006 Final Exam: June 12, 2006
Azar, Yossi
On-line and Approximation Algorithms Spring Semester, 2006 Final Exam: June 12, 2006 Lecturer: Prof problem on m (divisible by 3) machines. Job i has weight wi and a subset Si of size m/3 of the m machines. The job has to be assigned to one machine in Si. (a) Design a 4 competitive algorithm. (b) Show
A New Approximate Matrix Factorization for Implicit Time Integration in Air Pollution
Botchev, Mike
A New Approximate Matrix Factorization for Implicit Time Integration in Air Pollution Modeling + M on the one hand and its e#ciency on the other hand. For example, in air pollution modeling, AMF has been factorization, large sparse linear systems, sti# ODEs, method of lines, Rosenbrock methods, air pollution
A New Approximate Matrix Factorization for Implicit Time Integration in Air Pollution
Botchev, Mike
A New Approximate Matrix Factorization for Implicit Time Integration in Air Pollution Modeling M on the one hand and its efficiency on the other hand. For example, in air pollution modeling, AMF has been factorization, large sparse linear systems, stiff ODEs, method of lines, Rosenbrock methods, air pollution
Approximation Methods for Pricing Problems under the Nested Logit Model with Price Bounds
Rusmevichientong, Paat
Approximation Methods for Pricing Problems under the Nested Logit Model with Price Bounds W@orie.cornell.edu September 5, 2013 Abstract We consider two variants of a pricing problem under the nested logit model. In the first variant, the set of products offered to customers is fixed and we want to determine the prices
Besio, Walter G.
with up to three-fourths of all persons with epilepsy in developing countries. [1] Over 50 million people are ineffective in approximately 30% of patients and have side effects. We are developing a noninvasive, or minimally invasive, transcranial focal electrical stimulation (TFS) system through our novel concentric ring
The Exemplar Breakpoint Distance for non-trivial genomes cannot be approximated
Fertin, Guillaume
The Exemplar Breakpoint Distance for non-trivial genomes cannot be approximated Guillaume Blin1 - France guillaume.fertin@univ-nantes.fr Abstract. A promising and active field of comparative genomics con- sists in comparing two genomes by establishing a one-to-one correspon- dence (i.e., a matching) between
Approximating the True Evolutionary Distance Between Two Genomes Krister M. Swenson
Moret, Bernard
Approximating the True Evolutionary Distance Between Two Genomes Krister M. Swenson Mark Marron Joel V. Earnest-DeYoung Bernard M.E. Moret Abstract As more and more genomes are sequenced, evolutionary bi- ologists are becoming increasingly interested in evolution at the level of whole genomes
Fertin, Guillaume
On the Approximability of Comparing Genomes with Duplicates S??ebastien Angibaud, Guillaume Fertin.angibaud,guillaume.fertin,irena.rusu}@univnantes.fr Abstract. A central problem in comparative genomics consists in computing a (dis)simi larity measure between two genomes, e.g. in order to construct a phylogenetic tree. A large number of such measures has
A 2-Approximation Algorithms for Genome Rearrangements by Reversals and Transpositions 1
Gu, Qianping
A 2-Approximation Algorithms for Genome Rearrangements by Reversals and Transpositions 1 Qian of Texas at Dallas, Richardson, TX 75083 U.S.A. Keywords: Sorting of permutations, genome rearrangements: Recently, a new approach to analyze genomes evolving was proposed which is based on comparison of gene
Fertin, Guillaume
On the Approximability of Comparing Genomes with Duplicates S´ebastien Angibaud, Guillaume Fertin.angibaud,guillaume.fertin,irena.rusu}@univ-nantes.fr Abstract. A central problem in comparative genomics consists in computing a (dis-)simi- larity measure between two genomes, e.g. in order to construct a phylogenetic tree. A large number of such measures has
On the Approximability of the Exemplar Adjacency Number Problem for Genomes with Gene Repetitions
Zhu, Binhai
On the Approximability of the Exemplar Adjacency Number Problem for Genomes with Gene Repetitions the similarity between two genomes (or in general, be- tween any two sequences drawn from the same alphabet). For two genomes G and H drawn from the same set of n gene families and containing gene repeti- tions, we
Approximation Algorithms for the Minimum Bends Traveling Salesman Problem (Extended Abstract)
design and analysis. The usual metric, minimizing the total distance traveled, is an important one of other heavy machinery: for many such devices turning is an expensive operation. We give approximation, 11, 12, 21, 15], and has been a testbed for many of the most useful ideas in algorithm design
LIMITS AND APPROXIMATIONS FOR THE M/G/1 LIFO WAITINGTIME DISTRIBUTION
Whitt, Ward
LIMITS AND APPROXIMATIONS FOR THE M/G/1 LIFO WAITINGTIME DISTRIBUTION by Joseph Abate 1 and Ward Hammond Road, Ridgewood, NJ 074502908 2 AT&T Research, Room 2C178, Murray Hill, NJ 079740636 (wow
RELAXATION OF ENERGY AND APPROXIMATE RIEMANN SOLVERS FOR GENERAL PRESSURE LAWS IN FLUID DYNAMICS
Coquel, Frédéric
RELAXATION OF ENERGY AND APPROXIMATE RIEMANN SOLVERS FOR GENERAL PRESSURE LAWS IN FLUID DYNAMICS FR a relaxation of the nonlinear pressure law introducing an energy decomposition under the form = 1 + 2. The internal energy 1 is associated with a (simpler) pressure law p1(, 1); the energy 2 is advected by the flow
Fast Approximate Energy Minimization via Graph Cuts Yuri Boykov Olga Veksler Ramin Zabih
Field, David
Fast Approximate Energy Minimization via Graph Cuts Yuri Boykov Olga Veksler Ramin Zabih Computer of minimizing a large class of energy functions that occur in early vision. The major restriction is that the energy func- tion's smoothness term must only involve pairs of pix- els. We propose two algorithms
Berlin,Technische Universitt
interfaces Sebastian Mathiowetz1 , Hannes A. Bonhoff Institute of Fluid Mechanics and Engineering Acoustics-shaped contact interfaces by means of discretization. In this work the accuracy of the single equivalent approximation [1] and the interface mobility method [2] to be expected with regard to power transmission
Calculation of electric dipole hypershieldings at the nuclei in the HellmannFeynman approximation
Helgaker, Trygve
theorem provide useful criteria for basis-set completeness and for near HartreeFock quality of nuclear at the HartreeFock level of theory in the HellmannFeynman approximation. The nuclear electric hypershieldings on the practicality of the proposed scheme. The best results are obtained with the R12 and R12 basis sets, designed
A quantum algorithm to approximate the linear structures of Boolean functions
Hong-Wei Li; Li Yang
2015-01-20
We present a quantum algorithm for approximating the linear structures of a Boolean function $f$. Different from previous algorithms (such as Simon's and Shor's algorithms) which rely on restrictions on the Boolean function, our algorithm applies to every Boolean function with no promise. Here, our methods are based on the result of the Bernstein-Vazirani algorithm which is to identify linear Boolean functions and the idea of Simon's period-finding algorithm. More precisely, how the extent of approximation changes over the time is obtained, and meanwhile we also get some quasi linear structures if there exists. Next, we obtain that the running time of the quantum algorithm to thoroughly determine this question is related to the relative differential uniformity $\\delta_f$ of $f$. Roughly speaking, the smaller the $\\delta_f$ is, the less time will be needed.
The Gamow-Teller response within Skyrme random-phase approximation plus particle-vibration coupling
Yifei Niu; Gianluca Colo; Marco Brenna; Marco Brenna; Pier Francesco Bortignon; Jie Meng
2012-03-28
Although many random-phase approximation (RPA) calculations of the Gamow-Teller (GT) response exist, this is not the case for calculations going beyond the mean-field approximation. We apply a consistent model that includes the coupling of the GT resonance to low-lying vibrations, to nuclei of the $fp$ shell. Among other motivations, our goal is to see if the particle-vibration coupling can redistribute the low-lying GT$^+$ strength that is relevant for electron-capture processes in core-collapse supernova. We conclude that the lowering and fragmentation of that strength are consistent with the experimental findings and validate our model. However, the particle-vibration coupling cannot account for the quenching of the total value of the low-lying strength.
Real-time shape approximation and 5-D fingerprinting of single proteins
Yusko, Erik C; Eggenberger, Olivia; Houghtaling, Jared; Rollings, Ryan C; Walsh, Nathan C; Nandivada, Santoshi; Pindrus, Mariya; Hall, Adam R; Sept, David; Li, Jiali; Kalonia, Devendra S; Mayer, Michael
2015-01-01
This work exploits the zeptoliter sensing volume of electrolyte-filled nanopores to determine, simultaneously and in real time, the approximate shape, volume, charge, rotational diffusion coefficient, and dipole moment of individual proteins. We have developed the theory for a quantitative understanding and analysis of modulations in ionic current that arise from rotational dynamics of single proteins as they move through the electric field inside a nanopore. The resulting multi-parametric information raises the possibility to characterize, identify, and quantify individual proteins and protein complexes in a mixture. This approach interrogates single proteins in solution and determines parameters such as the approximate shape and dipole moment, which are excellent protein descriptors and cannot be obtained otherwise from single protein molecules in solution. Taken together, this five-dimensional characterization of biomolecules at the single particle level has the potential for instantaneous protein identifi...
Robust Validation Of Approximate 1-Matrix Functionals With Few-Electron Harmonium Atoms
Cioslowski, Jerzy; Matito, Eduard
2015-01-01
A simple comparison between the exact and approximate correlation components U of the electron-electron repulsion energy of several states of few-electron harmonium atoms with varying confinement strengths provides a superior validation tool for 1-matrix functionals. The robustness of this tool is clearly demonstrated in a survey of 14 known functionals, which reveals their substandard performance within different electron correlation regimes. Unlike spot-testing that employs dissociation curves of diatomic molecules or more extensive benchmarking against experimental atomization energies of molecules comprising one of standard sets, the present approach not only uncovers the flaws and patent failures of the functionals but, even more importantly, allows for pinpointing their root causes. Since the approximate values of U are computed at exact 1-densities, the testing requires minimal programming, and thus is particularly useful in quick screening of new functionals.
An SDE approximation for stochastic differential delay equations with colored state-dependent noise
Austin McDaniel; Ozer Duman; Giovanni Volpe; Jan Wehr
2014-12-09
We consider a general multidimensional stochastic differential delay equation (SDDE) with colored state-dependent noises. We approximate it by a stochastic differential equation (SDE) system and calculate its limit as the time delays and the correlation times of the noises go to zero. The main result is proven using a theorem about convergence of stochastic integrals by Kurtz and Protter. It formalizes and extends a result that has been obtained in the analysis of a noisy electrical circuit with delayed state-dependent noise, and may be used as a working SDE approximation of an SDDE modeling a real system, where noises are correlated in time and whose response to noise sources is delayed.
B. G. Konopelchenko; G. Ortenzi
2012-06-13
Quasiclassical approximation in the intrinsic description of the vortex filament dynamics is discussed. Within this approximation the governing equations are given by elliptic system of quasi-linear PDEs of the first order. Dispersionless Da Rios system and dispersionless Hirota equation are among them. They describe motion of vortex filament with slow varying curvature and torsion without or with axial flow. Gradient catastrophe for governing equations is studied. It is shown that geometrically this catastrophe manifests as a fast oscillation of a filament curve around the rectifying plane which resembles the flutter of airfoils. Analytically it is the elliptic umbilic singularity in the terminology of the catastrophe theory. It is demonstrated that its double scaling regularization is governed by the Painleve' I equation.
Zhukovsky, Sergei V; Takayama, Osamu; Shkondin, Evgeniy; Malureanu, Radu; Jensen, Flemming; Lavrinenko, Andrei V
2015-01-01
We experimentally demonstrate the effect of anomalous breakdown of the effective medium approximation in all-dielectric deeply subwavelength thickness ($d \\sim\\lambda/160-\\lambda/30$) multilayers, as recently predicted theoretically [H.H. Sheinfux et al., Phys. Rev. Lett. 113, 243901 (2014)]. Multilayer stacks are composed of alternating alumina and titania layers fabricated using atomic layer deposition. For light incident on such multilayers at angles near the total internal reflection we observe pronounced differences in the reflectance spectra for structures with 10-nm versus 20-nm thick layers, as well as for structures with different layers ordering, contrary to the predictions of the effective medium approximation. The reflectance difference can reach values up to 0.5, owing to the chosen geometrical configuration with an additional resonator layer employed for the enhancement of the effect. Our results are important for the development of new high-precision multilayer ellipsometry methods and schemes,...
Dahlqvist, P. [Royal Inst. of Technology, Stockholm (Sweden)
1996-08-01
We compute the Lyapunov exponent, the generalized Lyapunov exponents, and the diffusion constant for a Lorentz gas on a square lattice, thus having infinite horizon. Approximate zeta functions, written in terms of probabilities rather than periodic orbits, are used in order to avoid the convergence problems of cycle expansions. The emphasis is on the relaxation between the analytic structure of the zeta function, where a branch cut plays an important role, and the asymptotic dynamics of the system. The Lyapunov exponent for the corresponding map agrees with the conjectured limit {lambda}{sub map}=-2 log(R) + C + O(R) and we derive an approximate value for the constant C in good agreement with numerical simulations. We also find a diverging diffusion constant D(t){approx}log t and a phase transition for the generalized Lyapunov exponents.
The slope-dependent nuclear-symmetry energy within the effective surface approximation
J. P. Blocki; A. G. Magner; P. Ring
2015-06-08
The effective surface approximation is extended taking into account derivatives of the symmetry energy density per particle over the mean particle density. The isoscalar and isovector particle densities in this extended effective surface approximation are derived. The improved expressions of the surface symmetry energy, in particular, its surface tension coefficients in the sharp edged proton-neutron asymmetric nuclei take into account important gradient terms of the energy density functional. For most Skyrme forces the surface symmetry-energy constants and the corresponding neutron skins and isovector stiffnesses are calculated as functions of the Swiatecki derivative of the non-gradient term of the symmetry energy density per particle with respect to the isoscalar density. Using the analytical isovector surface energy constants in the framework of the Fermi-liquid droplet model we find energies and sum rules of the isovector giant dipole resonance structure in a reasonable agreement with the experimental data and other theoretical approaches.
The periodic standing-wave approximation: computations in full general relativity
Napoleon Hernandez; Richard H. Price
2008-12-23
The periodic standing wave method studies circular orbits of compact objects coupled to helically symmetric standing wave gravitational fields. From this solution an approximation is extracted for the strong field, slowly inspiralling motion of binary black holes and binary neutron stars. Previous work on this project has developed a method using a few multipoles of specially adapted coordinates well suited both to the radiation and the source regions. This method had previously been applied to linear and nonlinear scalar field models, to linearized gravity, and to a post-Minkowski approximation. Here we present the culmination of this approach: the application of the method in full general relativity. The fundamental equations had previously been developed and the challenge presented by this step is primarily a computational one which was approached with an innovative technique. The numerical results of these computations are compared with the corresponding results from linearized and post-Minkowksi computations.
Double-hybrid density-functional theory with meta-generalized-gradient approximations
Souvi, Sidi M. O. Sharkas, Kamal; Toulouse, Julien; CNRS, UMR 7616, Laboratoire de Chimie Thorique, F-75005 Paris
2014-02-28
We extend the previously proposed one-parameter double-hybrid density-functional theory [K. Sharkas, J. Toulouse, and A. Savin, J. Chem. Phys. 134, 064113 (2011)] to meta-generalized-gradient-approximation (meta-GGA) exchange-correlation density functionals. We construct several variants of one-parameter double-hybrid approximations using the Tao-Perdew-Staroverov-Scuseria (TPSS) meta-GGA functional and test them on test sets of atomization energies and reaction barrier heights. The most accurate variant uses the uniform coordinate scaling of the density and of the kinetic energy density in the correlation functional, and improves over both standard Kohn-Sham TPSS and second-order Mller-Plesset calculations.
Vortex in a weakly relativistic Bose gas at zero temperature and relativistic fluid approximation
B. Boisseau
2004-09-14
The Bogoliubov procedure in quantum field theory is used to describe a relativistic almost ideal Bose gas at zero temperature. Special attention is given to the study of a vortex. The radius of the vortex in the field description is compared to that obtained in the relativistic fluid approximation. The Kelvin waves are studied and, for long wavelengths, the dispersion relation is obtained by an asymptotic matching method and compared with the non relativistic result.
Dvirny, A. I.; Slyn'ko, V. I. E-mail: vitstab@ukr.net
2014-06-01
Inverse theorems to Lyapunov's direct method are established for quasihomogeneous systems of differential equations with impulsive action. Conditions for the existence of Lyapunov functions satisfying typical bounds for quasihomogeneous functions are obtained. Using these results, we establish conditions for an equilibrium of a nonlinear system with impulsive action to be stable, using the properties of a quasihomogeneous approximation to the system. The results are illustrated by an example of a large-scale system with homogeneous subsystems. Bibliography: 30 titles. (paper)
Abdelaziz, Omar; Shrestha, Som S
2014-01-01
Refrigerants are the life-blood of vapor compression systems that are widely used in Heating, Ventilation, Air-Conditioning, and Refrigeration (HVAC&R) applications. The HVAC&R community is currently transitioning from main-stream refrigerants that have high Global Warming Potential (GWP) to alternative lower-GWP refrigerants. During this transition, it is important to account for the life cycle climate performance of alternative refrigerants since their performance will be different than that of higher-GWP refrigerants. This requires the evaluation of the system performance with the new refrigerants. Unfortunately, it is extremely difficult to predict the realistic performance of new alternative refrigerants without experimental validation. One of the main challenges in this regard is modeling the compressor performance with high fidelity due to the complex interaction of operating parameters, geometry, boundary conditions, and fluid properties. High fidelity compressor models are computationally expensive and require significant pre-processing to evaluate the performance of alternative refrigerants. This paper presents a new approach to modeling compressor performance when alternative refrigerants are used. The new modeling concept relies on using existing compressor performance to create an approximate model that captures the dependence of compressor performance on key operating parameters and fluid properties. The model can be built using a myriad of approximation techniques. This paper focuses on Kriging-based techniques to develop higher fidelity approximate compressor models. Baseline and at least one alternative refrigerant performance data are used to build the model. The model accuracy was evaluated by comparing the model results with compressor performance data using other refrigerants. Preliminary results show that the approximate model can predict the compressor mass flow rate and power consumption within 5%.
B73 : Filtrage bayesien et approximation particulaire TP 4 : Navigation d'un robot mobile
LeGland, François
B73 : Filtrage bay´esien et approximation particulaire TP 4 : Navigation d'un robot mobile lundi 15 octobre 2007 Un robot mobile se d´eplace `a l'int´erieur d'un b^atiment dont le plan est],transpose(map)); hold on; colormap('gray'); axis xy; axis off; Figure 1: Plan(s) du b^atiment Le robot est rep
Aggelen, Helen van; Department of Chemistry, Duke University, Durham, North Carolina 27708 ; Yang, Yang; Yang, Weitao
2014-05-14
Despite their unmatched success for many applications, commonly used local, semi-local, and hybrid density functionals still face challenges when it comes to describing long-range interactions, static correlation, and electron delocalization. Density functionals of both the occupied and virtual orbitals are able to address these problems. The particle-hole (ph-) Random Phase Approximation (RPA), a functional of occupied and virtual orbitals, has recently known a revival within the density functional theory community. Following up on an idea introduced in our recent communication [H. van Aggelen, Y. Yang, and W. Yang, Phys. Rev. A 88, 030501 (2013)], we formulate more general adiabatic connections for the correlation energy in terms of pairing matrix fluctuations described by the particle-particle (pp-) propagator. With numerical examples of the pp-RPA, the lowest-order approximation to the pp-propagator, we illustrate the potential of density functional approximations based on pairing matrix fluctuations. The pp-RPA is size-extensive, self-interaction free, fully anti-symmetric, describes the strong static correlation limit in H{sub 2}, and eliminates delocalization errors in H{sub 2}{sup +} and other single-bond systems. It gives surprisingly good non-bonded interaction energies competitive with the ph-RPA with the correct R{sup ?6} asymptotic decay as a function of the separation R, which we argue is mainly attributable to its correct second-order energy term. While the pp-RPA tends to underestimate absolute correlation energies, it gives good relative energies: much better atomization energies than the ph-RPA, as it has no tendency to underbind, and reaction energies of similar quality. The adiabatic connection in terms of pairing matrix fluctuation paves the way for promising new density functional approximations.
Energy identity of approximate biharmonic maps to Riemannian manifolds and its application
Wang, Changyou
2011-01-01
We consider in dimension four weakly convergent sequences of approximate biharmonic maps to a Riemannian manifold with bi-tension fields bounded in $L^p$ for $p>\\frac43$. We prove an energy identity that accounts for the loss of hessian energies by the sum of hessian energies over finitely many nontrivial biharmonic maps on $\\mathbb R^4$. As a corollary, we obtain an energy identity for the heat flow of biharmonic maps at time infinity.
AN EFFICIENT SECOND ORDER IN TIME SCHEME FOR APPROXIMATING LONG TIME STATISTICAL PROPERTIES OF
AN EFFICIENT SECOND ORDER IN TIME SCHEME FOR APPROXIMATING LONG TIME STATISTICAL PROPERTIES of the following efficient second order in time scheme for the 2D Navier-Stokes equation in a periodic box: 3n+1 - 4n + n-1 2k + (2n - n-1 ) (2n - n-1 ) - n+1 = fn+1 , -n = n . The scheme is a combination of a 2
A. Frommer; K. Kahl; Th. Lippert; H. Rittich
2012-12-03
The Lanczos process constructs a sequence of orthonormal vectors v_m spanning a nested sequence of Krylov subspaces generated by a hermitian matrix A and some starting vector b. In this paper we show how to cheaply recover a secondary Lanczos process starting at an arbitrary Lanczos vector v_m. This secondary process is then used to efficiently obtain computable error estimates and error bounds for the Lanczos approximations to the action of a rational matrix function on a vector. This includes, as a special case, the Lanczos approximation to the solution of a linear system Ax = b. Our approach uses the relation between the Lanczos process and quadrature as developed by Golub and Meurant. It is different from methods known so far because of its use of the secondary Lanczos process. With our approach, it is now in particular possible to efficiently obtain {\\em upper bounds} for the error in the {\\em 2-norm}, provided a lower bound on the smallest eigenvalue of $A$ is known. This holds in particular for a large class of rational matrix functions including best rational approximations to the inverse square root and the sign function. We compare our approach to other existing error estimates and bounds known from the literature and include results of several numerical experiments.
Eikonal approximation in the theory of energy loss by fast charged particles
Matveev, V. I., E-mail: matveev.victor@pomorsu.ru; Makarov, D. N.; Gusarevich, E. S. [Lomonosov Pomor State University (Russian Federation)
2011-05-15
Energy losses in fast charged particles as a result of collisions with atoms are considered in the eikonal approximation. It is shown that the nonperturbative contribution to effective stopping in the range of intermediate impact parameters (comparable with the characteristic sizes of the electron shells of the target atoms) may turn out to be significant as compared to shell corrections to the Bethe-Bloch formula calculated in perturbation theory. The simplifying assumptions are formulated under which the Bethe-Bloch formula can be derived in the eikonal approximation. It is shown that the allowance for nonperturbative effects may lead to considerable (up to 50%) corrections to the Bethe-Bloch formula. The applicability range for the Bethe-Bloch formula is analyzed. It is concluded that calculation of the energy loss in the eikonal approximation (in the range of impact parameters for which the Bethe-Bloch formula is normally used) is much more advantageous than analysis based on the Bethe-Bloch formula and its modifications because not only the Bloch correction is included in the former calculations, the range of intermediate impact parameters is also taken into account nonperturbatively; in addition, direct generalization to the cases of collisions of complex projectiles and targets is possible in this case.
Testing the validity of the Kirkwood approximation using an extended Sznajd model
Timpanaro, Andr Martin
2015-01-01
We revisit the deduction of the exit probability of the one dimensional Sznajd model through the Kirkwood approximation [F. Slanina et al., Europhys. Lett. 82, 18006 (2008)]. This approximation is peculiar in that in spite of the agreement with simulation results [F. Slanina et al., Europhys. Lett. 82, 18006 (2008), R. Lambiotte and S. Redner, Europhys. Lett. 82, 18007 (2008), A. M. Timpanaro and C. P. C. Prado, 89, 052808 (2014)] the hypothesis about the correlation lenghts behind it are inconsistent and fixing these inconsistencies leads to the same results as a simple mean field. We use an extended version of the Sznajd model to test the Kirkwood approximation in a wider context. This model includes the voter, Sznajd and "United we Stand, Divided we Fall" (USDF) models [R. A. Holley and T. M. Liggett, Ann. Prob. 3, 643 (1975), K. Sznajd-Weron and J. Sznajd, Int. Journ. Mod. Phys. C 11, 1157 (2000)] as different parameter combinations, meaning that some analytical results from these models can be used to ev...
Validity of the linear coupling approximation in heavy-ion fusion reactions at sub barrier energies
K. Hagino; N. Takigawa; M. Dasgupta; D. J. Hinde; J. R. Leigh
1996-07-26
The role of higher order coupling of surface vibrations to the relative motion in heavy-ion fusion reactions at near-barrier energies is investigated. The coupled channels equations are solved to all orders, and also in the linear and the quadratic coupling approximations. Taking $^{64}$Ni + $^{92,96}$Zr reactions as examples, it is shown that all order couplings lead to considerably improved agreement with the experimentally measured fusion cross sections and average angular momenta of the compound nucleus for such heavy nearly symmetric systems. The importance of higher order coupling is also examined for asymmetric systems like $^{16}$O + $^{112}$Cd, $^{144}$Sm, for which previous calculations of the fusion cross section seemed to indicate that the linear coupling approximation was adequate. It is shown that the shape of the barrier distributions and the energy dependence of the average angular momentum can change significantly when the higher order couplings are included, even for systems where measured fusion cross sections may seem to be well reproduced by the linear coupling approximation.