恒定应力加速寿命试验的贝叶士方法

恒定应力加速寿命试验已在实践中广泛应用。但大多在已知失效分布和加速寿命试验模型下讨论、本文在失效分布未知条件下,用贝叶士方法首先给出各应力下失效率的估计。然后用这些估计值给出加速寿命模型,从而外推正常应力下的失效率估计。本文最后给出一个完整的例子,详细地叙述了使用这个方法的全过程。     

几何分布产品全样本场合步进应力加速寿命试验TFR模型下的统计分析

讨论了几何分布产品在步进应力加速试验TFR模型下寿命分布.给出了其寿命分布函数步进形式,在全样本场合利用极大似然估计方法和矩估计方法求出了未知参数的点估计,最后利用计算机模拟说明本文方法的可行性.     

几何分布截尾样本场合步进应力加速寿命试验TFR模型下的统计分析

讨论了几何分布产品在步进应力加速试验TFR模型下寿命分布.给出了其寿命分布函数步进形式,在截尾样本场合利用极大似然估计方法和拟矩估计方法求出了未知参数的点估计,最后利用计算机模拟考察了说明本文方法的可行性.     

威布尔分布场合下步进应力加速寿命试验的统计分析

本文对寿命分布为两参数威布尔分布,加速模型为逆幂律的情况,由定数截尾步进应力加速寿命试验数据获得加速模型中未知参数的点估计和区间估计,进而给出了加速系数的区间估计,并用一个模拟例子说明方法的应用．     

威布尔分布场合下进步应力加速寿命试验的统计分析

本文对寿命分布为两参数威布尔分布,加速模型为逆幂律的情况,由定数截尾步进应力加速寿命试验数据获得加速模型中未知参数的点估计和区间估计,进而给出了加速系数的区间估计,并用一个模拟例子说明方法的应用。     

混合加速寿命试验模型及其统计分析

本文结合序进应力加速寿命试验和恒定应力加速寿命试验提出了一种混合加速寿命试验,讨论了这种加速寿命试验的模型及其在寿命分布为指数分布和对数正态分布时的参数估计,导出了参数的最大的似然估计。     

Weibull分布恒定应力加速寿命试验的Bayes估计

对定时和定数截尾样本情形CE模型下Weibull分布场合恒定应力加速寿命试验进行了Bayes统计分析,利用Laplace方法给出了该模型的近似Bayes估计.最后通过模拟实例表明该Bayes估计是有效的.     

Weibull分布步进应力加速寿命试验的Bayes估计

本文研究了定时和定数截尾情形CE模型下Weibull分布场合步进应力加速寿命试验的Bayes估计.利用加速系数和加速方程将各种加速应力水平下的尺度参数换算为正常应力水平下的尺度参数,从而获得含正常应力下尺度参数的似然函数.在参数先验的选取时,尺度参数和加速系数分别取共轭先验和无信息先验,当形状参数m<1和m>1时分别取Beta分布和Gamma分布作为其先验.在平方损失下,利用Gibbs抽样和切片抽样给出了该模型参数的Bayes估计.最后,通过Monte Carlo模拟表明该Bayes估计是有效的.     

基于维纳过程步进应力加速退化试验的客观贝叶斯分析

高可靠性产品在加速寿命试验中其失效数据经常比较少,利用步进应力加速退化试验来评估产品寿命分布是一种非常好的方法.本文基于维纳过程的步进应力加速退化试验模型利用客观贝叶斯方法获得了其模型参数的无信息先验(Jefferys先验和Reference先验).并证明了对应的后验分布都是正常的.对于Jefferys先验和Reference先验下的后验提出相应的Gibbs抽样算法.最后,我们模拟对比了客观贝叶斯估计、贝叶斯估计和极大似然估计,模拟结果揭示了客观贝叶斯方法的优良性.     

WEIBULL分布步进应力加速寿命试验损伤失效率模型参数的近似极大似然估计和逆矩估计

Bhattacharyya和Soejoeti(1980)对步进应力加速寿命试验提出损伤失效率模型(TFR模型)．本针对TFR模型，对两参数Weibull分布，在步进应力加速试验下给出了参数的近似极大似然估计和逆矩估计，并通过Montr-Carlo模拟考察了估计的精度，比较了各估计的优劣。     

Local asymptotic normality and asymptotical minimax efficiency of the MLE under random censorship

Here we study the problems of local asymptotic normality of the parametric family of distributions and asymptotic minimax efficient estimators when the observations are subject to right censoring. Local asymptotic normality will be established under some mild regularity conditions. A lower bound for local asymptotic minimax risk is given with respect to a bowl-shaped loss function, and furthermore a necessary and sufficient condition is given in order to achieve this lower bound. Finally, we show that this lower bound can be attained by the maximum likelihood estimator in the censored case and hence it is local asymptotic minimax efficient.     

ANALYSIS OF THE PERIODIC VOLTERRA PREDATOR-PREY MODEL WITH UNDERCROWDING EFFECT

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Asymptotic distribution of the weighted least squares estimator

This paper derives the asymptotic distribution of the weighted least squares estimator (WLSE) in a heteroscedastic linear regression model. A consistent estimator of the asymptotic covariance matrix of the WLSE is also obtained. The results are obtained under weak conditions on the design matrix and some moment conditions on the error distributions. It is shown that most of the error distributions encountered in practice satisfy these moment conditions. Some examples of the asymptotic covariance matrices are also given.     

关于一类五阶常微分方程解的渐近性质

给出了一类五阶常微分方程所有解一致有界和当t→∞时收敛于零的充分条件。得到的结果包含并改善了Abou-El-Ela和Sadek1999年关于非自治微分方程渐近解的结果。     

关于线性秩统计量的渐近正态性及其收敛速度

本文讨论线性秩统计量的渐近正态性的条件及其收敛速度．推广了Hajek关于线性秩统计量收敛于正态分布的条件的重要定理，并得出了一个较易验证的充分条件．对于一般形式的计分函数，在一定条件下得出了相应线性秩统计量收敛于正态分布的速度．     

GLOBAL ASYMPTOTIC STABILITY OF THE PERIODIC LOTKA-VOLTERRA SYSTEM WITH TWO-PREDATORS AND ONE-PREY

The three species Lotka-Volterra periodic model with two predators and one prey is considered. A set of easily verifiable sufficient conditions is obtained. Finally, an example is given to illustrate the feasibility of these conditious.     

A STABILITY THEOREM FOR A CERTAIN FOURH-ORDER VECTOR DIFFERENTIAL FQUATION

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On pathwise super-exponential decay rates of solutions of scalar nonlinear stochastic differential equations

This paper studies the pathwise asymptotic stability of the zero solution of scalar stochastic differential equation of Itô type. In particular, we provide conditions for solutions to converge to zero at a given rate, which is faster than any exponential rate of decay. The results completely classify the rates of decay of many parameterised families of stochastic differential equations.     

具有三个成长阶段的单种群时滞模型的永久持续生存和全局稳定性

该文研究具有分布时滞和三个成长阶段的单种群模型,得到了系统永久持续生存的充分条件;同时通过构造Lyapunov 函数得到了系统全局渐近稳定的充分条件;最后建立具体模型说明所得结果的可行性.     

Joint asymptotic multinormality for a class of rank order statistics in multivariate paired comparisons

The joint asymptotic multinormality of certain linear signed-rank statistics introduced by Shane and Puri (1969) is established for the nonidentically distributed case; moreover, the usual restriction forbidding constant score generating functions is dropped. In addition, sufficient conditions more general than those of Shane and Puri are given for the convergence of certain dispersion matrices, and these conditions guarantee the asymptotic independence of the statistics under consideration.