Estimation of parameters of mixed failure time distribution

The problem of estimation of parameters of a mixture of degenerate and exponential distributions is considered. A new sampling scheme is proposed and the exact bias and the mean square error (MSE) of the maximum likelihood estimators of the parameters is derived. Moment estimators, their approximate biases and the MSE are obtained. Asymptotic distributions of the estimators are also obtained for both the cases.     

Bayes prediction of number of failures in weibull samples

This work is concerned with the Bayesian prediction problem of the number of components which will fail in a future time interval, when the failure times are Weibull distributed. Both the 1-sample and the 2-sample prediction problems are dealed with, and some choices of the prior densities on the distribution parameters are discussed which are relatively easy to work with and allow different degrees of knowledge on the failure mechanism to be incorporated in the predictive procedure. Useful relations between the predictive distribution on the number of future failures and the predictive distribution on the future failure times are derived. Numerical examples are also given.     

大学生志愿精神与校园文化建设探讨

近年来，随着奥运会、世博会等一系列重大活动的成功举办，志愿者活动获得了社会公众的广泛认可，受到了越来越多的重视和支持。在志愿者队伍中，大学生是一支非常重要的力量，他们秉承奉献、友爱、互助、进步的志愿精神在志愿活动的各个领域发挥了积极作用。大学生志愿者活动已经成为高校校园文化建设的重要内容，弘扬大学生志愿精神也逐渐成为了推进大学校园文化建设的重要途径之一。针对弘扬大学生志愿精神，促进校园文化建设进行探讨，以期为高校校园文化建设提供新思路。     

认知语境视角下社交语用失误成因分析

跨文化交际的本质是人与人之间的交际,对社交语用失误的解读必须考虑交际参与者的主观能动性和认知能力.在跨文化交际中,若认知心理状态不同的交际者对彼此制约交际的社交文化规约的心理可及程度较低,加上交际的瞬时性和省力原则的作用,说话人对听话人的认知语境假设选择的判断可能与听话人的真实认知语境假设选择不符,使得听话人推理出的说话人交际意图和说话人真实的交际意图不一致,从而导致社交语用失误.     

Voluntary Siting and Equity: The MRS Facility Experience in Native America

This article focuses on aspects of intragenerational and intergenerational equity in the context of a unique policy experiment: the effort of the U.S. government to site a monitored, retrievable storage (MRS) facility for high-level civilian nuclear waste. This process and its outcomes are examined from both normative and subjective perspectives. While the MRS siting process was designed to be equitable, its eventual focus on Native American communities raises profound questions about environmental justice, as well as procedural, outcome, and intergenerational equity in cross-cultural contexts. The diverse reactions among Native American tribes demonstrate that translating theoretical concepts of equity into practice is an extraordinarily complex exercise. The MRS siting process, instead of being a bold policy experiment that promoted equity, emerges substantially flawed after its implementation in the Native American context.     

Human resource development in small organizations

This article draws upon case-study research into human resource development (HRD) within three small organizations in the north west of England. It positions the case-study work within an overall framework of doctoral research and summarizes the research design; discusses the characteristics and values of small organizations and how they influence HRD policies and practices: presents findings and conclusions about HRD in the case-study organizations, focusing in particular upon one case in the voluntary sector; compares and contrasts the different models of HRD in the three cases; and concludes with some suggestions for further research.     

跨文化交际中的语用失误及策略研究

随着跨国交际日益增多,跨文化交际中的语用失误问题突显,由于思维方向不同,文化背景差异、母语负迁移等原因造成交际的冲突和失败。跨文化交际的语用失误需要依靠交际双方的顺应和宽容,提高对目的语文化的领悟力和敏感性去解决。     

三牙轮钻头滑动轴承失效分析

三牙轮钻头轴承的使用寿命直接决定了钻头的寿命。为了弄清三牙轮钻头轴承的失效形式、原因及机理，进一步提高三牙轮钻头轴承的寿命，分别对现场失效的三牙轮钻头轴承进行宏观和微观分析。结果表明，密封系统失效是轴承失效的主要原因之一。同时，轴承所受载荷过大且分布不均，温度过高导致材料表面金属强度和耐磨性降低，以及轴承与牙轮之间配合间隙过大，工作时晃动导致受力不均等原因也是造成牙轮钻头轴承的快速失效的主要原因。     

Reliability Research of Dependent Failure Systems Using Copula

The computation of reliability characteristics of a system that consists of dependent components sometimes becomes difficult, especially when a specific type of dependence is not identified. In this paper, some systems with arbitrary dependent components are studied using copula. In the system, the components are dependent on each other and the dependent relations may be either linear or nonlinear correlation. The efficient formulas are presented to compute the reliability characteristics, such as reliability function, failure rate and meantime to failure of series, parallel and k-out-of-n systems. The reliability functions of dependant systems are compared with independent system. At last, the numerical examples are presented to illustrate the results obtained in this paper.     

A class of semiparametric transormation frailty models with application to estimating treatment effects and heterogenity in aids clinical traials

Muitivariate failure time data are common in medical research; com¬monly used statistical models for such correlated failure-time data include frailty and marginal models. Both types of models most often assume pro¬portional hazards (Cox, 1972); but the Cox model may not fit the data well This article presents a class of linear transformation frailty models that in¬cludes, as a special case, the proportional hazards model with frailty. We then propose approximate procedures to derive the best linear unbiased es¬timates and predictors of the regression parameters and frailties. We apply the proposed methods to analyze results of a clinical trial of different dose levels of didansine (ddl) among HIV-infected patients who were intolerant of zidovudine (ZDV). These methods yield estimates of treatment effects and of frailties corresponding to patient groups defined by clinical history prior to entry into the trial.