软件可靠性模型及其参数估值技术

软件产品的可靠性评估主要取决于软件可靠性模型及其参数估值技术。本文探讨了六种软件可靠性增长模型的内在关系,提出了一个统一的软件可靠性增长模型,并从数理统计角度介绍了两种可靠性模型参数估值方法:最大似然估值法和最小均方误差估值法。最后,通过实例说明了软件可靠性模型及其参数估值技术在软件产品的可靠性评估方面的具体应用。     

The dynamic and stochastic instability of betas: Implications for forecasting stock returns

The purpose of this paper is to simultaneously investigate several important issues that feature the dynamic and stochastic behavior of beta coefficients for individual stocks and affect the forecasting of stock returns. The issues include randomness, nonstantionarity, and shifts in the mean and variance parameters of the beta coefficient, and are addressed within the framework of variable-mean-response (VMR) random coefficients models in which the problem of heteroscedasticity is present. Estimation is done using a four-step generalized least squares method. The hypotheses concerning randomness and nonstationarity of betas are tested. The time paths, sizes, and marginal rates of mean shifts are determined. The issue of variance shift is examined on the basis of five special tests, called T*, B, S', G and W. Then the impacts of the dynamic and stochastic instability on the estimation of betas is tested by a nonparametric procedure. Finally, the VMR models' ability of forecasting stock returns is evaluated against the standard capital asset pricing model. The empirical findings shed new light on the continuing debate as to whether the beta coefficient is random and nonstationary and have important implications for modeling and forecasting the measurement of performance and the determination of stock returns.     

OPTIMAL SWITCHING AND IMPULSE CONTROLS FOR DISTRIBUTED PARAMETER SYSTEMS

Optimal switching and impulse controls for a distributed parameter systems are considered.We prove that the value functions u_u(·) of approximating problems approach to the value functionu(·) of the original problem,while u_u(·) is the unique viscosity solution of the correspondingHamilton-Jacobi-Bellman system.We also construct an optimal control for the original problem viathe value function u(·).     

基于最佳均方预报的自相关过程控制图

给出一阶自回归过程的参数估计公式,利用估计的参数构建了基于最佳均方预报误差的控制图,并给出了过程启动后才发生漂移的平均运行链长（ARL）计算公式.将此控制图与利用估计的参数构建的单值控制图进行了比较,结果表明误差控制图总体上优于单值控制图.     

交流自动调速系统

介绍了交流调速系统基本结构、调试功能与方法及如何进行系统的参数设定，电机识别及调试中故障处理的方法。     

用矩阵法导出反馈放大器的基本放大电路

本文基于网络理论用矩阵法导出四种基本类型反馈放大器的基本放大电路,得出矩阵法导出基本放大电路的方法。     

大容量学科单项多项混合选择题的编程技术

本文详细地介绍了 Authorware中使用 ODBC数据源构建大容量学科单项、多项混合选择题的编程技术 ,文中对于系统数据源的自动注册、单项多项混合选择题库结构的构建、Authorware中库调用的方法与参数传递以及随机抽选算法都作了详细地介绍 ,为信息时代的教师快速制作单项多项混合选择题提供的一种便利快捷的途径。     

试析序参量与役使原理的整体方法论意义

本文在梳理序参量及其役使原理的具体含义的基础上,主要分析了序参量与役使原理之于整体论的意义:1.序参量作为一种总的规则所具有的支配性,表明了整体与部分之间不是同质的,具有等级差异;2.使高层次的整体对低层次的部分的控制能力、协调能力、选择能力等,建立在了更加牢固的定量化的基础之上,很好地表明了整体性质的可理解性;3.作为一种达到整体与部分之间沟通的方法,它体现了整体与部分间不可分割的互补联系。     

随机连续动态系统的连续时间随机逼近辨识的数值实现

本文讨论随机连续动态系统的连续时间随机逼近(CSA)辨识的数值实现及仿真.文中首先回顾了随机连续动态系统辨识的算法和理论分析结果,然后基于数值积分技术和常微分方程的数值解的欧拉法和龙格一库塔法,给出了CSA法的两种数值实现方法.仿真结果显示了本文方法的有效性.     

振动系统参数识别的最小二乘频域法

本文根据模态分析中的复模态理论,在频域中用最小二乘法拟合振动系统的传递函数,并用微型计算机识别结构的模态参数.