检索结果-内蒙古大学图书馆

Special Issue for Image Processing and numerical linear algebra

numerical Mathematics(theory,methods and applications) 2009年第4期 5-6页

作者： Michael K.Ng Eugene Tyrtyshnikov Department of Mathematics and Centre for Mathematical Imaging and Vision Hong Kong Baptist University Institute of Numerical Mathematics of the Russian Academy of Sciences and Institute for Computational Mathematics Hong Kong Baptist University

The Third International conference on Scientific Computing and Partial Differential Equations(SCPDE) was held from December 8 to December 12,2008 at Hong Kong Baptist *** was a sequel to similar conferences held in Hong Kong(2002 and 2005). The conference aims to promote research interests in scientific *** SCPDE 2008,two workshops on image processing and numerical linear algebra are organized to review recent scientific developments and explore exciting new directions in mathematical modeling and computational methods in these two *** are twenty one invited speakers in these two workshops(http://***/SCPDE08/).

关键词： Special Issue for Image Processing and numerical linear algebra

来源：评论

学校读者我要写书评

暂无评论

Stability Criterions for Switched linear Systems Based on Matrix Measure

Stability Criterions for Switched Linear Systems Based on Ma...

引用

4th IEEE conference on Industrial Electronics and applications

作者： Zou, Hongbo Li, Han Xu, Ouguan Hangzhou Dianzi Univ Inst Informat & Control Hangzhou 310018 Zhejiang Peoples R China China Bldg Tech Grp Co Ltd Inst Design 3 Beijing 100013 Peoples R China Zhejiang Univ Technol Hangzhou 310024 Peoples R China

ISBN: (纸本)9781424427994

The problem of stability analysis for a class of switched linear systems is studied in this paper based on the theory of matrix measure. The matrix measures of all subsystems are used to determine the stability of the switched linear systems. Based on this, sufficient conditions are reached, which can be used to determine the stability or instability of switched linear systems under arbitrary switching law. If a switching sequence satisfies some conditions, a theorem in this paper can be used to verify if it can stabilize the systems. The obtained conditions are simpler than the reported methods such as multi-Lyapunov functions and hence are easier to check. numerical examples are used to demonstrate these conditions.

关键词： Hybrid systems Switched Systems Matrix Measure

来源：评论

学校读者我要写书评

暂无评论

Output feedback SSR damping controller design based on modular discrete-time dynamic model of TCSC

引用

IET GENERATION TRANSMISSION & DISTRIBUTION 2009年第6期3卷 561-573页

作者： Joshi, S. R. Cheriyan, E. P. Kulkarni, A. M. Indian Inst Technol Bombay 400076 Maharashtra India

This paper presents the use of a modular, sample invariant, six samples per cycle, discrete-time model of a thyristor controlled series capacitor (TCSC) for output feedback-based subsynchronous resonance (SSR) damping controller (SSDC) design. An SSDC is used to alleviate the instability of torsional modes caused by external fixed capacitors used in conjunction with a TCSC. It is found that damping torque analysis-based design of an SSDC using a non-local signal like generator slip is straightforward and the resulting SSDC has a simple compensator structure. On the other hand, the residues and pole-zero configuration with the line current magnitude as a feedback signal are such that it is relatively more difficult to obtain a robust design, especially if several subsynchronous torsional modes are present. Eigenvalue analysis and digital simulation studies indicate that the TCSC model can accurately predict the behaviour of a TCSC with and without a damping controller.

关键词： pole-zero configuration Control of electric power systems linear algebra (numerical analysis) feedback Discrete control systems damping torque analysis Power convertors and power supplies to apparatus output feedback SSR damping controller design modular discrete-time dynamic model damping Control system analysis and synthesis methods eigenvalues and eigenfunctions torsional mode instability TCSC Stability in control theory eigenvalue analysis control system synthesis poles and zeros stability thyristor controlled series capacitor Other power apparatus and electric machines power capacitors subsynchronous resonance thyristor applications discrete time systems

来源：评论

学校读者我要写书评

暂无评论

A Coordinate Gradient Descent Method for Nonsmooth Nonseparable Minimization

引用

numerical Mathematics(theory,methods and applications) 2009年第4期2卷 377-402页

作者： Zheng-Jian Bai Michael K. Ng Liqun Qi School of Mathematical Sciences Xiamen University Xiamen 361005 China Centre for Mathematical Imaging and Vision and Department of Mathematics Hong Kong Baptist University Kowloon Tong Hong Kong Department of Applied Mathematics The Hong Kong Polytechnic University Hung Horn Hong Kong

This paper presents a coordinate gradient descent approach for minimizing the sum of a smooth function and a nonseparable convex *** find a search direction by solving a subproblem obtained by a second-order approximation of the smooth function and adding a separable convex *** a local Lipschitzian error bound assumption,we show that the algorithm possesses global and local linear convergence *** also give some numerical tests(including image recovery examples) to illustrate the efficiency of the proposed method.

关键词： Coordinate descent global convergence linear convergence rate

来源：评论

学校读者我要写书评

暂无评论

A High-Quality Preconditioning Technique for Multi-Length-Scale Symmetric Positive Definite linear Systems

引用

numerical Mathematics(theory,methods and applications) 2009年第4期2卷 469-484页

作者： Ichitaro Yamazaki Zhaojun Bai Wenbin Chen Richard Scalettar Department of Computer Science University of California Davis CA 95616 USA School of Mathematical Sciences Fudan University Shanghai 200433 China Department of Physics University of California Davis CA95616 USA

We study preconditioning techniques used in conjunction with the conjugate gradient method for solving multi-length-scale symmetric positive definite linear systems originating from the quantum Monte Carlo simulation of electron interaction of correlated materials. Existing preconditioning techniques are not designed to be adaptive to varying numerical properties of the multi-length-scale systems. In this paper, we propose a hybrid incomplete Cholesky （HIC） preconditioner and demonstrate its adaptivity to the multi-length-scale systems. In addition, we propose an extension of the compressed sparse column with row access （CSCR） sparse matrix storage format to efficiently accommodate the data access pattem to compute the HIC preconditioner. We show that for moderately correlated materials, the HIC preconditioner achieves the optimal linear scaling of the simulation. The development of a linear-scaling preconditioner for strongly correlated materials remains an open topic.

关键词： Preconditioning multi-length-scale incomplete Cholesky factorization quantum MonteCarlo simulation.

来源：评论

学校读者我要写书评

暂无评论

Computing quadratic approximations for the isochrons of oscillators: A general theory and advanced numerical methods

Computing quadratic approximations for the isochrons of osci...

引用

2009 IEEE/ACM International conference on Computer-Aided Design, ICCAD 2009

作者： Şuvak, Önder Demir, Alper Koç University Istanbul Turkey

ISBN: (纸本)9781605588001

We first review the notion of isochrons for oscillators, which has been developed and heavily utilized in mathematical biology in studying biological oscillations. Isochrons were instrumental in introducing a notion of generalized phase for an oscillation and form the basis for oscillator perturbation analysis formulations. Calculating the isochrons of an oscillator is a very difficult task. Except for some very simple planar oscillators, isochrons can not be calculated analytically and one has to resort to numerical techniques. Previously proposed numerical methods for computing isochrons can be regarded as brute-force, which become totally impractical for non-planar oscillators with dimension more than two. In this paper, we present a precise and carefully developed theory and advanced numerical techniques for computing local but quadratic approximations for isochrons. Previous work offers the theory and the numerical methods needed for computing only linear approximations for isochrons. Our treatment is general and applicable to oscillators with large dimension. We present examples for isochron computations, verify our results against exact calculations in a simple case, and allude to several applications among many where quadratic approximations of isochrons will be of use. Copyright 2009 ACM.

关键词： numerical methods

来源：评论

学校读者我要写书评

暂无评论

A Review of Vector Convergence Acceleration methods, With applications to linear algebra Problems

引用

INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY 2009年第8期109卷 1631-1639页

作者： Brezinski, C. Redivo-Zaglia, M. Univ Padua Dipartimento Matemat Pura & Applicata I-35121 Padua Italy Univ Sci & Tech Lille Flandres Artois CNRS UFR Math Pures & Appl Lab Paul PainleveUMR 8524 F-59655 Villeneuve Dascq France

In this article, in a few pages, we will try to give an idea of convergence acceleration methods and extrapolation procedures for vector sequences, and to present some applications to linear algebra problems and to the treatment of the Gibbs phenomenon for Fourier series in order to show their effectiveness. The interested reader is referred to the literature for more details. In the bibliography, due to space limitation, we will only give the more recent items, and, for older ones, we refer to Brezinski and Redivo-Zaglia, Extrapolation methods. (Extrapolation methods. theory and practice, North-Holland, 1991). This book also contains, on a magnetic support, a library (in Fortran 77 language) for convergence acceleration algorithms and extrapolation methods. (C) 2008 Wiley Periodicals, Inc. Int J Quantum Chem 109: 1631-1639, 2009

关键词： extrapolation projection sequence transformations linear algebra linear systems regularization Fourier series Gibbs phenomenon

来源：评论

学校读者我要写书评

暂无评论

Dependence modelling with copula in probabilistic studies, a practical approach based on numerical experiments

引用

作者： Dutfoy, Anne Lebrun, Régis EDF-RandD France EADS-IW France

ISBN: (纸本)9780415485135

Taking into account the stochastic dependence between sources of uncertainties is of uttermost importance in reliability studies. Most of the time, the practitioner has a handful of scalars measuring correlations between these sources, and he is faced to the challenge of describing the dependence structure based on this information. In this communication, we show that this approach might be irrelevant in the general case, but may be improved with some additional work. In the first section, we show that the use of the linear correlation coefficient should be avoided as a general way to represent stochastic dependence. We introduce the notion of copula as the most exhaustive representation of stochastic dependence, then we define the notion of measure of association. We confirm that the linear correlation is not such a measure, and we present three such measures (Spearman's rho, Kendall's tau and coefficients of tail dependence) that can be viewed as replacements of the usual linear correlation data. Then, in the context of an aeronautic application dedicated to the risks induced by the use of electronic protable devices during a flight, we perform a numerical experiment in order to check within which bounds we can rely on measure of association for the description of the stochastic dependence. The conclusion aims at giving some experimental guidelines for stochastic modelling based on such measures. © 2009 Taylor & Francis Group.

关键词： Risk assessment

来源：评论

学校读者我要写书评

暂无评论

numerical methods for palindromic eigenvalue problems: Computing the anti-triangular Schur form

引用

numerical linear algebra WITH applications 2009年第1期16卷 63-86页

作者： Mackey, D. Steven Mackey, Niloufer Mehl, Christian Mehrmann, Volker Tech Univ Berlin Inst Math D-10623 Berlin Germany Western Michigan Univ Dept Math Kalamazoo MI 49008 USA Univ Birmingham Sch Math Birmingham B15 2TT W Midlands England

We present structure-preserving numerical methods for the eigenvalue problem of complex palindromic pencils. Such problems arise in control theory, as well as from palindromic linearizations of higher degree palindromic matrix polynomials. A key ingredient of these methods is the development of an appropriate condensed form-the anti-triangular Schur form. Ill-conditioned problems with eigenvalues near the unit circle, in particular near +/- 1, are discussed. We show how a combination of unstructured methods followed by a structured refinement can be used to solve such problems accurately. Copyright (C) 2008 John Wiley & Sons, Ltd.

关键词： nonlinear eigenvalue problem palindromic matrix polynomial palindromic pencil Schur form anti-triangular form Jacobi algorithm structured deflation method palindromic QR-algorithm

来源：评论

学校读者我要写书评

暂无评论

A class of approximate inverse preconditioners for solving linear systems

引用

INTERNATIONAL JOURNAL OF COMPUTER MATHEMATICS 2009年第7期86卷 1243-1252页

作者： Zhang, Yong Huang, Ting-Zhu Liu, Xing-Ping Gu, Tong-Xiang Univ Elect Sci & Technol China Sch Appl Math Chengdu 610054 Sichuan Peoples R China Inst Appl Phys & Computat Math Lab Computat Phys Beijing 100088 Peoples R China

Some preconditioners for accelerating the classical iterative methods are given in Zhang et al. [Y. Zhang and T.Z. Huang, A class of optimal preconditioners and their applications, Proceedings of the Seventh International conference on Matrix theory and Its applications in China, 2006. Y. Zhang, T.Z. Huang, and X.P. Liu, Modified iterative methods for nonnegative matrices and M-matrices linear systems, Comput. Math. Appl. 50 (2005), pp. 1587-1602. Y. Zhang, T.Z. Huang, X.P. Liu, A class of preconditioners based on the (I+S())-type preconditioning matrices for solving linear systems, Appl. Math. Comp. 189 (2007), pp. 1737-1748]. Another kind of preconditioners approximating the inverse of a symmetric positive definite matrix was given in Simons and Yao [G. Simons, Y. Yao, Approximating the inverse of a symmetric positive definite matrix, linear algebra Appl. 281 (1998), pp. 97-103]. Zhang et al. 's preconditioners and Simons and Yao's are generalized in this paper. These preconditioners are all of low construction cost, which all could be taken as approximate inverse of M-matrices. numerical experiments of these preconditioners applied with Krylov subspace methods show the effectiveness and performance, which also show that the preconditioners proposed in this paper are better approximate inverse for M-matrices than Simons'.

关键词： preconditioning M-matrix Krylov subspace method sparse approximate inverse

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：