求实对称三对角矩阵特征值的递归算法

许多对称矩阵特征值问题最后归结为解实对称三对角矩阵特征值问题。在文章中为区间分半法(二分法)求实对称三对角矩阵特征值设计了一个递归算法。用一个递归函数可以求出所有特征值,且能求重特征值。     

关于矩阵秩的一个重要不等式的改进

根据Sylvester不等式、矩阵秩的性质、线性子空间的性质及矩阵的满秩分解,给出了一个重要不等式的一个改进形式.     

Using diagrams as tools for the solution of non-routine mathematical problems

The Mathematics education community has long recognized the importance of diagrams in the solution of mathematical problems. Particularly, it is stated that diagrams facilitate the solution of mathematical problems because they represent problems’ structure and information (Novick & Hurley, 2001; Diezmann, 2005). Novick and Hurley were the first to introduce three well-defined types of diagrams, that is, network, hierarchy, and matrix, which represent different problematic situations. In the present study, we investigated the effects of these types of diagrams in non-routine mathematical problem solving by contrasting students’ abilities to solve problems with and without the presence of diagrams. Structural equation modeling affirmed the existence of two first-order factors indicating the differential effects of the problems’ representation, i.e., text with diagrams and without diagrams, and a second-order factor representing general non-routine problem solving ability in mathematics. Implicative analysis showed the influence of the presence of diagrams in the problems’ hierarchical ordering. Furthermore, results provided support for other studies (e.g. Diezman & English, 2001) which documented some students’ difficulties to use diagrams efficiently for the solution of problems. We discuss the findings and provide suggestions for the efficient use of diagrams in the problem solving situation.     

采用自相似分析进行视频中的背景识别

当今的视频监控系统已经越来越智能化,从中涌现的各种最新技术研究都预示着它的广阔前景.这些新技术中,视频场景的背景识别技术拥有着相当可观的实际应用价值.本文提出了一种对视频序列进行自相似分析,从而进行背景识别的方法.该方法比起传统的使用帧间柱状图差分的方法,在实时性和直观性上都做得非常好.     

外资在华制药企业技术战略分析

生物制药行业是21世纪的前瞻性行业,也是外资大力争夺创新资源的行业。本文基于1985—2005年的专利数据,主要从创新范围和创新规模两方面分析了制药行业外资技术竞争以及创新活动的特点。本文原创性地运用聚类的统计方法,定义了规模-范围矩阵(简称为双 S 矩阵),对外资技术策略的特点进行分类,进而识别各类外资的角色。本文的研究结论为行业相关政策以及企业战略的制定提供参考。     

Slip energy recovery of a rotor-side field oriented controlled wound rotor induction motor fed by matrix converter

This paper investigates rotor-side field oriented control of a wound-rotor induction motor using the slip energy recovery principle. The proposed drive system uses a matrix converter to transfer the slip energy from the rotor into the mains instead of using ac-dc-ac converter whilst the stator side is fixed to the grid. Operation at both subsynchronous and supersynchronous regions is possible with the proposed drive system. Simulation studies of the proposed doubly fed induction motor drive system verify the good control performance of the system in transient and steady-state conditions.     

矩阵乘法的来源和意义

本文依据矩阵的乘法规则探寻出它的实际意义 ,再联系理论上的价值 ,揭示了矩阵乘法的必要性     

一类特殊矩阵的特征值

本文利用矩阵A =αβT 的特征值, 对与矩阵k1 I + k2αβT 的特征值相关的一些典型题     

基于波士顿咨询集团矩阵的大学学科规划研究

波士顿咨询集团矩阵是对企业经营的全部产品或者业务组合进行整体分析的一种重要的战略工具。本文分析大学利用波士顿咨询集团矩阵进行学科规划的情况,并且对大学利用波士顿咨询集团矩阵进行学科和专业规划的情况进行评价。     

Delay-dependent robust<Emphasis Type="Italic">H</Emphasis><Subscript>∞</Subscript> control for a class of uncertain switched systems with time delay

For linear switched system with both parameter uncertainties and time delay, a delay-dependent sufficient condition for the existence of a new robustH _∞ feedback controller was formulated in nonlinear matrix inequalities solvable by an LMI-based iterative algorithm. Compared with the conventional state-feedback controller, the proposed controller can achieve better robust control performance since the delayed state is utilized as additional feedback information and the parameters of the proposed controllers are changed synchronously with the dynamical characteristic of the system. This design method was also extended to the case where only delayed state is available for the controller. The example of balancing an inverted pendulum on a cart demonstrates the effectiveness and applicability of the proposed design methods. Project (No. 2002CB312200) supported by the National Basic Research Program (973) of China