Optimizing Ridge Generalized Least Squares for Structural Equation Modeling

Ridge generalized least squares (RGLS) is a recently proposed estimation procedure for structural equation modeling. In the formulation of RGLS, there is a key element, ridge tuning parameter, whose value determines the efficiency of parameter estimates. This article aims to optimize RGLS by developing formulas for the ridge tuning parameter to yield the most efficient parameter estimates in practice. For the formulas to have a wide scope of applicability, they are calibrated using empirical efficiency and via many conditions on population distribution, sample size, number of variables, and model structure. Results show that RGLS with the tuning parameter determined by the formulas can substantially improve the efficiency of parameter estimates over commonly used procedures with real data being typically nonnormally distributed.     

单纯阵的分类及特征值估计

本文给出了单纯阵新的等价条件,从对角形的角度建立起单纯阵的一种分类方法。按照这种分类法,我们研究了某些特殊单纯阵的特征值的估计,推广并改进了[2—6]的有关结果。     

Learning from history for teaching in the future

Reflecting on the learning process of topologist Stephen Smale, certain properties and characteristics of that process are selected and analysed: the question and anticipation of future mathematics, the generalising potential thereof, and the shift from after-image or `model of ...' to pre-image or `model for ...'. These features are explored for the benefit of the design of learning-teaching sequences in mathematics education, and are illustrated in a variety of examples. This revised version was published online in August 2006 with corrections to the Cover Date.     

面向成本的设计中成本估算方法的研究

设计阶段决定了产品成本的60%-70%。日益加剧的市场竞争促使人们愈来愈重视对设计阶段的产品成本估算方法的研究。本文论述了近几十年来国内外在这一领域的发展概况及趋势,从并行设计的角度提出面向成本的设计(design for cost, DFC)的思想,在分析DFC中全生命周期成本的构成及其估算方法的基础上,建立基于CAD/CAPP模型的成本估算框架体系,在产品设计阶段不但考虑产品的技术性能,还考虑产品的经济性能,实现参数化成本估算,从而实现了考虑成本的优化设计,使得设计出的产品更加适应市场的需求,有助于提高企业在市场上的竞争力。     

多元模糊线性回归模型的参数估计

该文考虑了多元模糊线性回归模型,先将一元模糊线性回归模型的参数估计的结果加以推广,接着给出了多元线性回归模型参数的h-最优线性相关估计。     

离散线性时变系统的状态观测器

放弃Luenberger状态观测器理论对系统完全可观测性的要求 ,提出了一般离散线性时变系统的状态观测器的设计方法。对j =i,i- 1,给出了系统完全 (i,j,Ti)可重构的新概念 ,且给出了可重构的充要条件     

一般Gauss-Markov模型中参数岭估计的可容许性的一个证明

讨论一般Gauss-Markov模型中参数岭估计的有关问题，并在均方误差矩阵意义下，证明了一般岭估计在线性估计类中是否容许估计。     

基于自适应约简相关向量机的光照色度估计

提出了一种新的自适应约简相关向量机回归算法来估计图像的光照色度以达到色彩一致性目的.在稀疏贝叶斯学习的框架下,该算法首先以多核形式自适应结合全局核函数和局部核函数扩展相关向量机,然后应用改进的保局投影来约简多核输入矩阵的列维数以减少训练时间.为了估计光照色度,通过图像色度直方图的模糊中心值和其相应光源值训练算法.基于真实图像的实验表明所提算法优于支持向量机和相关向量机且其训练时间小于相关向量机.     

An improved channel estimation with multipath search for MIMO-OFDM systems

INTRODUCTION Multimedia wireless services require reliable high-bit-rate transmission over mobile radio channels. One of the challenges in designing such systems is the mitigation of fading propagation effects within the prescribed bandwidth and power limitations. Multi- ple-input and multiple-output (MIMO) techniques can be implemented to obtain a capacity gain in rich scattering environments without increasing the bandwidth or transmit power and/or to obtain the diversity gain to comba…     

光学仪器结构可靠性设计

分析了光学仪器中结构主要失效模式，提出了结构可靠性分布函数及基本的设计方法。对结构可靠性的设计与分配做了详细的研究和分析并给出了结论性的结果。