钢-混凝土连续组合梁的变曲变形计算

基于奇异函数表示钢-混凝土连续组合梁的抗弯刚度,推出了钢-混凝土连续组合梁发生弯曲变形时的挠曲线通解.并通过算例验证该方法的正确性及通用性.     

Distributional Equivalence and Subcompositional Coherence in the Analysis of Compositional Data,Contingency Tables and Ratio-Scale Measurements

We consider two fundamental properties in the analysis of two-way tables of positive data: the principle of distributional equivalence, one of the cornerstones of correspondence analysis of contingency tables, and the principle of subcompositional coherence, which forms the basis of compositional data analysis. For an analysis to be subcompositionally coherent, it suffices to analyze the ratios of the data values. A common approach to dimension reduction in compositional data analysis is to perform principal component analysis on the logarithms of ratios, but this method does not obey the principle of distributional equivalence. We show that by introducing weights for the rows and columns, the method achieves this desirable property and can be applied to a wider class of methods. This weighted log-ratio analysis is theoretically equivalent to “spectral mapping”, a multivariate method developed almost 30 years ago for displaying ratio-scale data from biological activity spectra. The close relationship between spectral mapping and correspondence analysis is also explained, as well as their connection with association modeling. The weighted log-ratio methodology is used here to visualize frequency data in linguistics and chemical compositional data in archeology. The first author acknowledges research support from the Fundación BBVA in Madrid as well as partial support by the Spanish Ministry of Education and Science, grant MEC-SEJ2006-14098. The constructive comments of the referees, who also brought additional relevant literature to our attention, significantly improved our article.     

求解一类四阶奇异边值问题的新算法

在再生核空间W5[0,1]中求解一类四阶奇异边值,给出精确解的级数形式的精确表达式.证明近似解一致收敛于精确解.数值算例验证了算法的有效性.     

高阶线性常微分方程非振动解的零点个数问题

研究了含有一个参数的高阶线性常微分方程的有界非振动解零点个数问题,将二阶线性常微分方程中有界非振动解零点个数问题的结论推广到高阶线性常微分方程情况上。     

求解含有转向点的奇异扰动问题的新算法

本文在再生核空间W3[0,1]中研究含有两个二阶转向点的奇异扰动问题,给出了这类方程精确解的表达式,算例表明近似解的误差随着结点数的增加单调递减.     

计算机辅助网络计划图中单代号网络到双代号网络的算法实现

在利用计算机技术辅助网络图自动生成工具的研制过程中,必然遇到的一个关键问题是单代号网络到双代号网络图的转化问题。通过引入７条关联矩阵变换规则,首次实现了单代号网络到双代号网络的计算机算法     

一类分阶段传播的广义SIS传染病模型的全局分析与控制

通过构造Liapunov函数,应用微分方程定性理论,得到一类分阶段传播的广义SIS传染病模型的全局稳定性的充分条件.对系统的不稳定情况,通过线性化和极点配置,得到了使系统在无病平衡点处稳定的控制率.最后用数值模拟验证了结论的合理性.     

不确定离散广义时滞系统的鲁棒H2控制

基于线性矩阵不等式法讨论了不确定离散广义时滞系统的鲁棒H2控制问题.目的是设计一个可容许的状态反馈控制律,对系统所有容许的不确定参数,使得闭环系统是容许的且满足所要求H2性能,即闭环系统的H2范数小于一个给定的正数γ.在分析的基础上,给出了该问题可解的一个矩阵不等式的充分条件及控制器的一个代数表达式.     

有界三次系统（Ⅱ）

本文是《有界三次系统[Ⅰ]》的继续,用讨论三次系统无穷远奇点的方法,得到了无穷远处只有一个奇点时,由三次系统的系数直接给出了判断该三次系统有界性的充分条件。     

奇摄动拟线性系统狄利克雷问题的一个定理的证明

改进文［１］定理７．４的证明．