与对合矩阵可交换的反对合矩阵

讨论与对合矩阵可交换的反对合矩阵。主。要结果如下：（1）给出了与n阶对合矩阵可交换的反对合矩阵的一种表示;（2）对于2阶对合矩阵A,如果A≠±I（I是单位矩阵）。那么与A可交换的反对合矩阵一共有4个,它们是±玎和±进;（3）对于3阶对合矩阵A,如果A≠±I,那么与A可交换的全体反对合矩阵为±iI和±iA,以及±[iik-i]p^-1,±P[-iik-i]P^-1,±P[ikl1＋k^2/l-k]P^-1,P[-ikl-1＋k^2/l-k]P^-1其中k是任意复数,l是任意非零复数;当廿（A）=-1时,P是A与diag{1,-1,-1,这一对相似矩阵之间的相似因子;当tr（A）=1时,P是A与diag{-1,1,1}之间的相似因子。     

高校体育教学“三自主”选课模式的现状与思考

"三自主"选课模式是在科学发展教育观的指导下进行的"以人为本、健康第一"的现代体育教育观念的探索,但在高校体育课程设置、课程教学、课程评价等方面存在有悖于"健康第一"的指导思想的地方,有待改进。     

Variance and Invariance in Expert and Novice Triple Junipers

Abstract

The purpose of this study was to examine relative timing, relative distance, and effector independence characteristics of the triple jump. We videotaped expert and novice triple jumpers using standing and running starts. On some trials, the triple jumpers were required to take off from their nondominant leg. Gentner's (1987) interaction test was used to assess the proportional duration model in describing the timing of the component submovements. For both experts and novices, the proportional durations varied with the type of start. For experts, the relative timing of the jump components was independent of the take-off leg. The findings were mixed for the novices. Similar results were obtained when relative distance was examined. These results are discussed with respect to constructs related to variability in skilled performance.     

Linear Algebra Students' Understanding of Similar Matrices and Matrix Representations of Linear Transformations in a MATLAB-Assisted Learning Environment

Abstract

The purpose of this research study was to understand how mathematics majors make sense of similar matrices, a linear algebra topic that is rich in internal and external connections, in a series of in-depth qualitative interviews in a technology-assisted (MATLAB) learning environment. The study was also an attempt to develop a cognitive theory in mathematics majors’ treatment of similar matrices and matrix representations of linear transformations in a computer-assisted learning environment by drawing primarily on three aspects of the experimental mathematics methodology, made possible by using modern digital tools to enhance learning: testing conjectures, suggesting proofs, and, computing lengthy hand derivations (Borwein &; Bailey, 2003 Borwein, J. M., &; Bailey, D. H. (2003). Experiments in mathematics: Computational paths to discovery. Natick, MA: AK Peters. [Google Scholar]). The analysis revealed a diversity of innovative ways by which research participants coordinated analytic and computational (MATLAB) methods for understanding matrix similarity and its connections to the rest of linear algebra. The paper concludes by offering pedagogical implications and recommendations for further research.     

基于波士顿矩阵的科研产出均衡度评价

将波士顿矩阵引入到研究所的科研产出均衡度评价. 根据科研管理的实际情况,将波士顿矩阵的象限内容,以及矩阵的横、纵坐标进行重新定义,并通过中国科学院ARP系统数据计算得出的科研产出基尼系数进行均衡度评价分析.     

基于改进局部空间自相关分析的萝北县耕地保护分区

本文通过结合耕地面积与距离修正反距离空间权重矩阵,首次构建改进的局部空间自相关分析方法,并运用空间计量模型的信息准则验证其合理性和可行性;以耕地质量指数为空间变量,运用改进的局部空间自相关分析法,分析黑龙江省萝北县不同类型耕地质量的空间聚集特征及空间关联结果,并据此提出详细的耕地保护分区方案。研究结果表明：①验证了改进的空间自相关分析方法的合理性和准确性;②不同类型耕地质量在空间分布上呈现相似的集聚性规律。正相关类型（HH型和LL型）多以带状或片区形式出现,聚集性较强;负相关类型（HL和LH型）无明显集中区域,面积较小,且零星分布;③将耕地保护划分为核心保护区、重点改良区、适度保护区和综合改良区4个一级类和11个二级类,并分别从耕地自然条件、利用水平和产出效益角度提出了相应的耕地保护措施。     

专业领域知识环境中数据摄取工具设计与实现

专业领域知识环境(SKE)以本体作为知识组织体系与传统数据组织结构存在的差异,导致底层数据无法直接调用,从而引出数据摄取工具的讨论。首先介绍Virto系统的数据摄取工具,在此基础上提出SKE数据摄取工具的设计理念,重点阐述工具实现过程中的关键技术点,并描述工具的应用场景和工具的效果评价。最后总结工具的可操作性及改进思路。     

基于电压闭环控制的矩阵变换器仿真研究

针对矩阵变换器开环控制碰到扰动输出电压波形不能自动调节的问题,采取电压闭环的控制方式,通过坐标系变换将输出电压采样变换得到空间矢量,与目标电压矢量进行比较得到偏差量,以此来进行反馈控制,并运用MATLAB软件进行器件建模及控制策略、电压闭环控制方法的仿真。通过对两种典型干扰仿真研究,表明电压闭环控制方法对于输入干扰抑制的有效性。     

一类分块Hermite矩阵特征值的简便求法及其推广

给出求解一类特殊分块Hermite矩阵的特征值与特征向量的简便方法,并对该方法作了进一步的推广．