检索结果-内蒙古大学图书馆

On the use of simplex methods in constructing quadratic models

Science China Mathematics 2007年第7期50卷 913-924页

作者： Qing-hua ZHOU 1 College of Mathematics and Computer,Hebei University,Baoding 071002,China 2 State key laboratory of scientific and engineering computing,Institute of Computational Mathematics and scientific/engineering computing,Academy of Mathematics and Systems Science,Chinese Academy of Sciences,Beijing 100080,China College of Mathematics Computer Hebei University Baoding 071002 China State Key Laboratory of Scientific Engineering Computing Institute of Computational Mathematics Scientific/Engineering Computing Academy of Mathematics Systems Science Chinese Academy of Sciences Beijing 100080 China

In this paper, we investigate the quadratic approximation methods. After studying the basic idea of simplex methods, we construct several new search directions by combining the local information progressively obtained during the iterates of the algorithm to form new subspaces. And the quadratic model is solved in the new subspaces. The motivation is to use the information disclosed by the former steps to construct more promising directions. For most tested problems, the number of functions evaluations have been reduced obviously through our algorithms.

关键词： unconstrained optimization trust region method quadratic model Lagrange function simplex methods direct methods 90C56

来源：评论

学校读者我要写书评

暂无评论

Splitting iteration methods for non-Hermitian positive definite systems of linear equations

引用

Hokkaido Mathematical Journal 2007年第4期36卷 801-814页

作者： Bai, Zhong-Zhi State Key Laboratory of Scientific/Engineering Computing Institute of Computational Mathematics and Scientific/Engineering Computing Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100080 P.O. Box 2719 China

For large sparse system of linear equations with a non-Hermitian positive definite coefficient matrix, we review the recently developed Hermitian/skew-Hermitian splitting (HSS) iteration, normal/skew-Hermitian splitting (NSS) iteration, positive-definite/ skew-Hermitian splitting (PSS) iteration, and block triangular/skew-Hermitian splitting (BTSS) iteration. These methods converge unconditionally to the exact solution of the linearsystem, with the upper bounds of their convergence factors being only dependent on the spectrum of the Hermitian (or normal, or positive-definite) splitting matrix, but independent of the spectrum of the skew-Hermitian splitting matrix as well as the eigenvectors of all matrices involved. © 2007 by the University of Notre Dame. All rights reserved.

关键词： Block triangular matrix Hermitian and skew-Hermitian splitting Non-Hermitian matrix Normal/Skew-Hermitian splitting Positive definite matrix Positivedefinite/Skew-Hermitian splitting Splitting iteration method

来源：评论

学校读者我要写书评

暂无评论

Explicit Multi-Symplectic Methods for Hamiltonian Wave Equations

引用

Communications in Computational Physics 2007年第4期2卷 662-683页

作者： Jialin Hong Shanshan Jiang Chun Li Hongyu Liu State Key Laboratory of Scientific and Engineering Computing Institute of Computational MathematicsAcademy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100080P.R.China Graduate School Chinese Academy of SciencesBeijing 100080P.R.China Department of Mathematics The Chinese University of Hong KongShatinN.T.Hong Kong.

In this paper,based on the multi-symplecticity of concatenating symplectic Runge-Kutta-Nystrom(SRKN)methods and symplectic Runge-Kutta-type methods for numerically solving Hamiltonian PDEs,explicit multi-symplectic schemes are constructed and investigated,where the nonlinear wave equation is taken as a model *** comparisons are made to illustrate the effectiveness of our newly derived explicit multi-symplectic integrators.

关键词： Hamiltonian wave equations multi-symplectic integration symplectic Runge-Kutta methods symplectic Runge-Kutta-Nystrom methods.

来源：评论

学校读者我要写书评

暂无评论

Quality Assessment for Image Coding Based on Matching Pursuit

Quality Assessment for Image Coding Based on Matching Pursui...

引用

IEEE International Conference on Multimedia and Expo (ICME)

作者： Jianxin Pang Rong Zhang Lu Lu Zhengkai Liu MOE-Microsoft Key Laboratory of Multimedia Computing and Communication Department of Electronic Engineering and Information Science University of Science and Technology Hefei Anhui China

Valuation of image coding relies on not only the efficiency of the coding, but also the quality of the coded image. We present a new objective quality assessment metric for image coding based on matching pursuit. First of all, we get the characteristics of the most important structure by projecting the reference image onto the base functions from a dictionary using matching pursuit. Secondly, we process the reference image and gain the structure information of the images in the order of importance, projecting the images onto the structural characteristics. Finally the objective quality score is given by comparing the differences of structure information between the reference and coded images. Experimental results show that the proposed approach is well consistent with the subjective quality score.

关键词： Quality assessment Image coding Matching pursuit algorithms Image quality Humans Layout Image segmentation PSNR Laboratories Multimedia computing

来源：评论

学校读者我要写书评

暂无评论

AN ITERATIVE ALGORITHM FOR ROBUST KERNEL PRINCIPAL COMPONENT ANALYSIS

AN ITERATIVE ALGORITHM FOR ROBUST KERNEL PRINCIPAL COMPONENT...

引用

2007 International Conference on Machine Learning and Cybernetics(IEEE第六届机器学习与控制论国际会议)

作者： LEI WANG NENG-HAI YU DAO-YI SHEN YAN-WEI PANG MOE-MS Key Laboratory of Multimedia Computing and Communication Department of Electronic Engineerin School of Electronic Information Engineering Tianjin University Tianjin 300072 China

Principal Component Analysis (PCA) has been proven to be an efficient method in dimensionality reduction, feature extraction and pattern *** Principal Component Analysis (KPCA) can be considered as a natural nonlinear generalization of PCA, which performs linear PCA in a high dimensional space implicitly by using kernel ***, both conventional PCA and KPCA suffer from the deficiency of being sensitive to *** robust KPCA has to eigen-decompose the Gram matrix directly in each step and is much more computationally infeasible due to the large size of the matrix when the number of training samples is *** extending existing robust PCA algorithm using kernel methods, we present a novel robust adaptive algorithm for calculating the kernel principal *** proposed method not only preserves the characteristic of capturing underlying nonlinear structure of KPCA but also is robust against outliers by restraining the effect of outlying *** with existing robust KPCA methods, our method is performed without having to store the kernel matrix, which can reduce significantly the storage *** addition, our method shows the potential of expansibility to the incremental learning *** results on synthetic data indicate that our improved algorithm is effective and promising.

关键词： Robust principal component analysis Robust kernel principal component analysis Outliers Dimensionality reduction Feature extraction

来源：评论

学校读者我要写书评

暂无评论

A series of non-Noether conservative quantities and Mei symmetries of nonconservative systems

引用

Chinese Physics B 2007年第3期16卷 599-604页

作者：刘鸿基傅景礼唐贻发 Institute of Mathematical Physics Shangqiu Teacher's College Shangqiu 476000 China Department of Physics Zhejiang Sci-Tech University Hangzhou 310018 China State Key Laboratory of Scientific and Engineering Computing Chinese Academy of Sciences Beijing 100080 China Shanghai University Shanghai Institute of Applied Mathematics and Mechanics Shanghai 200072 China

In this paper Mei symmetry is introduced for a nonconservative system. The necessary and sufficient condition for a Mei symmetry to be also a Lie symmetry is derived. It is proved that the Mei symmetry leads to a non-Noether conservative quantity via a Lie symmetry, and deduces a Lutzky conservative quantity via a Lie point symmetry.

关键词： Mei symmetry non-Noether conservative quantity Lutzky conservative quantity nonconservative system

来源：评论

学校读者我要写书评

暂无评论

keywords Extracting as Text Chance Discovery

Keywords Extracting as Text Chance Discovery

引用

International Conference on Fuzzy Systems and Knowledge Discovery (FSKD)

作者： Zhenya Zhang Honemei Cheng Schoold of Electronic and Information Engineering Anhui Institute of Architecture and Industry Hefei China MOE-Microsoft Key Laboratory of Multimedia Computing and Communication University of Science and Technology Hefei China Department of AIA Hefei China

keyword auto-extracting is focused by researchers on information retrieval, data mining, chance discovery and others application. In this paper, new algorithm, CCG(Cognition & Concept Graph, for text chance discovery is presented based on cognition with data depth as measurement. When the keywords in a document are treated as chances in the document, those keywords can be extracted by CGC automatically. In CGC, concepts of a document are represented as maximum connected sub graphs of the basic graph for the document and the cognition of reader/author on a term is weighted with data depth. The correlation for word and concept is defined and the formula for the correlation calculating is given. Experimental results show that keywords extracted by CCG can describe the document and author/reader's cognition much better than keywords extracted by others technologies such as frequency accumulating or key Graph.

关键词： Data mining Cognition Frequency Data engineering Information retrieval Visualization Man machine systems Laboratories Multimedia computing Industrial electronics

来源：评论

学校读者我要写书评

暂无评论

Discrete variational principle and first integrals for Lagrange-Maxwell mechanico-electrical systems

引用

Chinese Physics B 2007年第3期16卷 570-577页

作者：傅景礼戴桂冬萨尔瓦多·希梅尼斯唐贻发 Department of Physics Zhejiang Sci-Tech University Hangzhou 310018 China State Key Laboratory of Scientific and Engineering Computing ICMSEC Academy of Mathematies and System Science Chinese Academy of Sciences Beijing 100080 China Departament de Matematica Aplicáda TTII E. T.S.I. Telecomunicación Universidad Politécnica de Madrid 28040-Madrid Spain Graduate School of the Chinese Academy of Sciences Beijing 100080 China

This paper presents a discrete vaxiational principle and a method to build first-integrals for finite dimensional Lagrange-Maxwell mechanico-electrical systems with nonconservative forces and a dissipation function. The discrete variational principle and the corresponding Euler-Lagrange equations are derived from a discrete action associated to these systems. The first-integrals are obtained by introducing the infinitesimal transformation with respect to the generalized coordinates and electric quantities of the systems. This work also extends discrete Noether symmetries to mechanico-electrical dynamical systems. A practical example is presented to illustrate the results.

关键词： discrete variational principle first integral mechanico-electrical systems

来源：评论

学校读者我要写书评

暂无评论

Monotone projected gradient methods for large-scale box-constrained quadratic programming

引用

Science China Mathematics 2006年第5期49卷 688-702页

作者： ZHOU Bin, GAO Li & DAI Yuhong School of Mathematical Sciences and LMAM, Peking University, Beijing 100871, China State key laboratory of scientific and engineering computing, Institute of Computational Mathematics and scientific/engineering computing, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing 100080, China School of Mathematical Sciences LMAM Peking University Beijing 100871 China State Key Laboratory of Scientific Engineering Computing Institute of Computational Mathematics Scientific/Engineering Computing Academy of Mathematics Systems Science Chinese Academy of Sciences Beijing 100080 China

Inspired by the success of the projected Barzilai-Borwein (PBB) method for largescale box-constrained quadratic programming, we propose and analyze the monotone projected gradient methods in this paper. We show by experiments and analyses that for the new methods,it is generally a bad option to compute steplengths based on the negative gradients. Thus in our algorithms, some continuous or discontinuous projected gradients are used instead to compute the steplengths. Numerical experiments on a wide variety of test problems are presented, indicating that the new methods usually outperform the PBB method.

关键词： projected gradients, monotone gradient methods, box-constrained quadratic programming, large-scale problems.

来源：评论

学校读者我要写书评

暂无评论

Conformal Invariant Asymptotic Expansion Approach for Solving （3＋1）-Dimensional JM Equation

引用

Communications in Theoretical Physics 2006年第6期45卷 979-984页

作者： LI Zhi-Fang RUAN Hang-Yu Department of Physics Ningbo University Ningbo 315211 China Nonlinear Science Center and Physics Department Ningbo University Ningbo 315211 China State Key Laboratory of Scientific and Engineering Computing Institute of Computational Mathematics and Scientific Engineering Computing Academy of Mathematics and System Sciences the Chinese Academy of Sciences P.O. Box 2719 Beijing 100080 China

The （3＋1）-dimensional Jimbo-Miwa （JM） equation is solved approximately by using the conformal invariant asymptotic expansion approach presented by Ruan. By solving the new （3＋1）-dimensional integrable models, which are conformal invariant and possess Painlevé property, the approximate solutions are obtained for the JM equation, containing not only one-soliton solutions but also periodic solutions and multi-soliton solutions. Some approximate solutions happen to be exact and some approximate solutions can become exact by choosing relations between the parameters properly.

关键词：（3＋1）-dimensional Jimbo-Miwa （JM） equation conformal invariant asymptotic expansion approach Painlevé property approximate and exact solutions

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：