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An Iterative Discontinuous Galerkin Method for Solving the Nonlinear Poisson Boltzmann Equation

Communications in computational Physics 2014年第7期16卷 491-515页

作者： Peimeng Yin Yunqing Huang Hailiang Liu Hunan Key Laboratory for Computation and Simulation in Science and Engineering School of Mathematics and Computational ScienceXiangtan UniversityXiangtan 411105P.R.China Iowa State University Mathematics DepartmentAmesIA 50011USA.

An iterative discontinuous Galerkin(DG)method is proposed to solve the nonlinear Poisson Boltzmann(PB)*** first identify a function space inwhich the solution of the nonlinear PB equation is iteratively approximated through a series of linear PB equations,while an appropriate initial guess and a suitable iterative parameter are selected so that the solutions of linear PB equations are monotone within the identified solution *** the spatial discretization we apply the direct discontinuous Galerkin method to those linear PB *** precisely,we use one initial guess when the Debye parameter l=O(1),and a special initial guess for l≪1 to ensure *** iterative parameter is carefully chosen to guarantee the existence,uniqueness,and convergence of the *** particular,iteration steps can be reduced for a variable iterative *** one and two-dimensional numerical results are carried out to demonstrate both accuracy and capacity of the iterative DG method for both cases of l=O(1)and l≪***(m+1)th order of accuracy for L2 and mth order of accuracy for H1 for Pm elements are numerically obtained.

关键词： Poisson-Boltzmann equation nonlinear existence uniqueness DDG methods numerical flux.

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Mathematical analysis of a PML model obtained with stretched coordinates and its application to backward wave propagation in metamaterials

Mathematical analysis of a PML model obtained with stretched...

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作者： Huang, Yunqing Li, Jichun Yang, Wei Hunan Key Laboratory for Computation and Simulation in Science Engineering Xiangtan University Hunan 411105 China Department of Mathematical Sciences University of Nevada Las Vegas Las Vegas NV 89154-4020 United States

We investigate the well-posedness of a perfectly matched layer model developed by Cohen and Monk [Comput Methods Appl Mech Eng 169 (1999), 197-217]. A new time-domain finite element method is proposed to solve the model. A novel feature of the scheme is that the number of unknowns is reduced to two from four in the original form. The scheme's effectiveness is demonstrated through numerical experiments. © 2013 Wiley Periodicals, Inc.

关键词： Maxwell equations

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Two classes of implicit–explicit multistep methods for nonlinear stiff initial-value problems

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Applied Mathematics and computation 2014年 247卷 47-60页

作者： Aiguo Xiao Gengen Zhang Xing Yi School of Mathematics and Computational Science Hunan Key Laboratory for Computation and Simulation in Science and Engineering Xiangtan University Xiangtan Hunan 411105 China

The initial value problems of nonlinear ordinary differential equations which contain stiff and nonstiff terms often arise from many applications. In order to reduce the computation cost, implicit–explicit (IMEX) methods are often applied to these problems, i.e. the stiff and non-stiff terms are discretized by using implicit and explicit methods, respectively. In this paper, we mainly consider the nonlinear stiff initial-value problems satisfying the one-sided Lipschitz condition and a class of singularly perturbed initial-value problems, and present two classes of the IMEX multistep methods by combining implicit one-leg methods with explicit linear multistep methods and explicit one-leg methods, respectively. The order conditions and the convergence results of these methods are obtained. Some efficient methods are constructed. Some numerical examples are given to verify the validity of the obtained theoretical results.

关键词： Stiff problems Singular perturbation problems Implicit–explicit multistep methods One-leg methods Linear multistep methods Convergence

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Time-splitting finite difference method with the wavelet-adaptive grids for semiclassical Gross–Pitaevskii equation in supercritical case

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Journal of computational Physics 2014年 267卷 146-161页

作者： Xueyang Li Aiguo Xiao School of Mathematics and Computational Science Hunan Key Laboratory for Computation and Simulation in Science and Engineering Xiangtan University Xiangtan Hunan 411105 PR China

The Gross–Pitaevskii equation is the model equation of the single-particle wave function in a Bose–Einstein condensation. A computation difficulty of the Gross–Pitaevskii equation comes from the semiclassical problem in supercritical case. In this paper, we apply a diffeomorphism to transform the original one-dimensional Gross–Pitaevskii equation into a modified equation. The adaptive grids are constructed through the interpolating wavelet method. Then, we use the time-splitting finite difference method with the wavelet-adaptive grids to solve the modified Gross–Pitaevskii equation, where the approximation to the second-order derivative is given by the Lagrange interpolation method. At last, the numerical results are given. It is shown that the obtained time-splitting finite difference method with the wavelet-adaptive grids is very efficient for solving the one-dimensional semiclassical Gross–Pitaevskii equation in supercritical case and it is suitable to deal with the local high oscillation of the solution.

关键词： Gross–Pitaevskii equation Wavelet-adaptive grids Time-splitting finite difference method Interpolating wavelet Lagrange interpolation method

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Parallelization of a DEM code based on CPU-GPU heterogeneous architecture

Parallelization of a DEM code based on CPU-GPU heterogeneous...

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26th International Conference on Parallel computational Fluid Dynamics, ParCFD 2013

作者： Yue, Xiaoqiang Zhang, Hao Luo, Congshu Shu, Shi Feng, Chunsheng School of Mathematics and Computational Science Xiangtan University 411105 Hunan China Heat and Mass Transfer Technological Center Technical University of Catalonia 08222 Terrassa Spain Hunan Key Laboratory for Computation and Simulation in Science and Engineering Key Laboratory of Intelligent Computing and Information Processing of Ministry of Education Xiangtan University 411105 Hunan China

ISBN: (纸本)9783642539619

Particulate flows are commonly encountered in both engineering and environmental applications. The discrete element method (DEM) has attracted plentiful attentions since it can predict the whole motion of the particulate flow by monitoring every single particle. However the computational capability of the method relies strongly on the numerical scheme as well as the hardware environment. In this study, a parallelization of a DEM based code titled Trubal was implemented. Numerical simulations were carried out to show the benefits of this research. It is shown that the final parallel code gave a substantial acceleration on the Trubal. By simulating 6,000 particles using a NVIDIA Tesla C2050 card together with Intel Core-Dual 2.93 GHz CPU, an average speedup of 4.69 in computational time was obtained. © Springer-Verlag Berlin Heidelberg 2014.

关键词： Finite difference method

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Underlying scaling relationships between solar activity and geomagnetic activity revealed by multifractal analyses

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Journal of Geophysical Research: Space Physics 2014年第9期119卷 7577-7586页

作者： Yu, Zu-Guo Anh, Vo Eastes, Richard Hunan Key Laboratory for Computation and Simulation in Science and Engineering Ministry of Education Xiangtan University Xiangtan Hunan China School of Mathematical Sciences Queensland University of Technology Brisbane QLD Australia Florida Space Institute University of Central Florida Orlando FL United States

This paper identifies some scaling relationships between solar activity and geomagnetic activity. We examine the scaling properties of hourly data for two geomagnetic indices (a_p and AE), two solar indices (solar X-rays X_l and solar flux F10.7), and two inner heliospheric indices (ion density Ni and flow speed Vs) over the period 1995-2001 by the universal multifractal approach and the traditional multifractal analysis. We found that the universal multifractal model (UMM) provides a good fit to the empirical K(q) and τ(q) curves of these time series. The estimated values of the Lévy index α in the UMM indicate that multifractality exists in the time series for a_p, AE, X_l, and Ni, while those for F10.7 and Vs are monofractal. The estimated values of the nonconservation parameter H of this model confirm that these time series are conservative which indicate that the mean value of the process is constant for varying resolution. Additionally, the multifractal K(q) and τ(q) curves, and the estimated values of the sparseness parameter C₁ of the UMM indicate that there are three pairs of indices displaying similar scaling properties, namely a_p and X_l, AE and Ni, and F10.7 and Vs. The similarity in the scaling properties of pairs (a_p,X_l) and (AE,Ni) suggests that a_p and X_l, AE and Ni are better correlated - in terms of scaling - than previous thought, respectively. But our results still cannot be used to advance forecasting of a_p and AE by X_l and Ni, respectively, due to some reasons. key Points The scaling properties of the geomagnetic and the solar indices are examinedThe results suggest that multifractality exists in a_p, AE, Xl, and ion densityThe scaling similarity of the a_p and Xl data suggests flare-storm dependence ©2014. American Geophysical Union. All Rights Reserved.

关键词： geomagnetic indices multifractal analysis scaling property solar indices universal multifractal model

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26th Annual computational Neuroscience Meeting (CNS*2017): Part 3 Antwerp, Belgium. 15-20 July 2017 Abstracts

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BMC NEUROscience 2017年第SUPPL 1期18卷 95-176页

作者： [Anonymous] Department of Neuroscience Yale University New Haven CT 06520 USA Department Physiology & Pharmacology SUNY Downstate Brooklyn NY 11203 USA NYU School of Engineering 6 MetroTech Center Brooklyn NY 11201 USA Departament de Matemàtica Aplicada Universitat Politècnica de Catalunya Barcelona 08028 Spain Institut de Neurobiologie de la Méditerrannée (INMED) INSERM UMR901 Aix-Marseille Univ Marseille France Center of Neural Science New York University New York NY USA Aix-Marseille Univ INSERM INS Inst Neurosci Syst Marseille France Laboratoire de Physique Théorique et Modélisation CNRS UMR 8089 Université de Cergy-Pontoise 95300 Cergy-Pontoise Cedex France Department of Mathematics and Computer Science ENSAT Abdelmalek Essaadi’s University Tangier Morocco Laboratory of Natural Computation Department of Information and Electrical Engineering and Applied Mathematics University of Salerno 84084 Fisciano SA Italy Department of Medicine University of Salerno 84083 Lancusi SA Italy Dipartimento di Fisica Università degli Studi Aldo Moro Bari and INFN Sezione Di Bari Italy Data Analysis Department Ghent University Ghent Belgium Coma Science Group University of Liège Liège Belgium Cruces Hospital and Ikerbasque Research Center Bilbao Spain BIOtech Department of Industrial Engineering University of Trento and IRCS-PAT FBK 38010 Trento Italy Department of Data Analysis Ghent University Ghent 9000 Belgium The Wellcome Trust Centre for Neuroimaging University College London London WC1N 3BG UK Department of Electronic Engineering NED University of Engineering and Technology Karachi Pakistan Blue Brain Project École Polytechnique Fédérale de Lausanne Lausanne Switzerland Departement of Mathematics Swansea University Swansea Wales UK Laboratory for Topology and Neuroscience at the Brain Mind Institute École polytechnique fédérale de Lausanne Lausanne Switzerland Institute of Mathematics University of Aberdeen Aberdeen Scotland UK Department of Integrativ

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Firefly algorithm solving equal-task multiple traveling salesman problem

Communications in Computer and Information Science

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Communications in Computer and Information science 2014年 472卷 304-307页

作者： Ma, Jianhua Li, Mingfu Zhang, Yuyan Zhou, Houming School of Mechanical Engineering Xiangtan University Xiangtan China Hunan Key Laboratory for Computation and Simulation in Science and Engineering Xiangtan China

ISBN: (纸本)9783662450482

A kind of equal-task multiple traveling salesman problem (ET-mTSP) was proposed based on the mTSP and its corresponding mathematical model was constructed;Then, a series of discrete operations for firefly algorithm (FA) were conducted to solve this problem;Finally, the results and analysis of experiments showed that the improved algorithm was efficient and suitable for solving such ET-mTSP. © Springer-Verlag Berlin Heidelberg 2014.

关键词： Problem solving

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Jacobi spectral Galerkin methods for fractional integro-differential equations

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Calcolo 2014年第4期52卷 519-542页

作者： Yang, Yin Hunan Key Laboratory for Computation and Simulation in Science and Engineering School of Mathematics and Computational Science Xiangtan University Xiangtan People’s Republic of China

We propose general spectral and pseudo-spectral Jacobi–Galerkin methods for fractional order integro-differential equations of Volterra type. The fractional derivative is described in the Caputo sense. We provide rigorous error analysis for spectral and pseudo-spectral Jacobi–Galerkin methods, which show that the errors of the approximate solution decay exponentially in $$L^\infty $$ norm and weighted $$L^2$$ -norm. The numerical examples are given to illustrate the theoretical results.

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New upper and lower eigenvalue bounds for the solution of the continuous algebraic riccati equation

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Asian Journal of Control 2014年第1期16卷 284-291页

作者： Liu, Jianzhou Zhang, Juan Department of Mathematics and Computational Science Xiangtan University Xiangtan Hunan 411105 China Hunan Key Laboratory for Computation and Simulation in Science and Engineering Xiangtan University Hunan 411105 China

In this paper, applying majorization inequalities, new upper and lower bounds for summation of eigenvalues (including the trace) of the solution of the continuous algebraic Riccati equation are presented. Corresponding numerical examples illustrate that our new bounds extend some of the recent results. © 2012 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society.

关键词： Eigenvalues and eigenfunctions

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