On Upshifted Reversed Mean Residual Life Order

Recently, the concept of reversed mean residual life order based on the mean of the random variable X _t  = (t ? X | X ≤ t), t > 0, called the reversed residual life, defined for the nonnegative random variable X, has been introduced in the literature. In this paper, a stochastic order based on the shifted version of the reversed mean residual life is proposed, based on the reversed mean residual life function for a random variable X with support (l _X , ∞), where l _X may be negative infinity, and its properties are studied. Closure under the Poisson shock model and properties for spare allocation are also discussed.     

Statistical analysis of a two-unit dependent repairable system

Maximum likelihood estimators are investigated a for lr-out-of 2:G repairable system when failures and repairs are statistically dependent. Under two censoring schemes Accelerated Life Testing Procedure (ALTP) is used to obtain the estimates. Information matrices are supplied and a special case when the failure and repair phenomenon are independent of each other is considered.     

Bathtub distributions: a review

Bathtub distributions are characterized by bathtub failure rate functions . These are possibly more realisitic models than the monotone failure rate models . A systematic account of such distributions is not available and this review aims to give such an account . We give some easily verifiable conditions to check the bathtub property of a distribution along with methods to construct such distributions . We also discuss some stochastic and reliablity mechanisms which lead to bathtub distributions. These include mixtures ( stochastic failure rate models ) , series system , stochastic differential equation models and so on. We also review inference on bathtub distributions. The paper concludes with a rather exhaustive list of bathtub distributions.     

Bayes estimators of the average failure rates

In the present paper we have proposed a Bayesian approach for making inferences from accelerated life tests which do not require distributional assumptions     

Estimation of parameters and reliability from generalized life models

Simultaneous estimation of parameters with p (≥ 2) components, where each component has a generalized life distribution, is considered under a sum of squared error loss function. Improved estimators are obtained which dominate the maximum likelihood and the niinimum mean square estimators. Robustness of the improved estimators is shown even when the component distributions are dependent. The result is extended to the estimation of the system reliability when the components are connected in series. Several numerical studies are performed to demonstrate the risk improvement and the Pitman closeness of the new estimators.     

Characterizations of the poisson process using,the variance

Let γ(t) be the residual life at time t of the renewal process {A(t), t > 0}, which has F as the common distribution function of the inter-arrival times. In this article we prove that if Var(γ(t)) is constant, then F will be exponentially or geometrically distributed under the assumption F is continuous or discrete respectively. An application and a related example also are given.     

冷却剂参数对铣槽喷管低周疲劳寿命的影响

采用有限体积流固耦合计算方法、非线性有限元热结构耦合分析方法和局部应变法研究大面积比铣槽喷管三维再生冷却槽道在循环工作条件下的热结构变形与低周疲劳寿命,并对比分析了冷却剂质量流量与入口温度对铣槽喷管疲劳使用寿命的影响。计算结果表明,铣槽喷管热结构响应呈现复杂的三维效应,应变较大位置主要分布在与肋连接的内衬区域,喷管中部的残余应变量最大;冷却槽道低周疲劳寿命分布和热结构响应基本一致,最小寿命位于喷管中部与肋相连的内衬区域燃气侧;随冷却剂质量流量增加,铣槽喷管低周疲劳寿命不断提高;随冷却剂入口温度增加喷管尾部低周疲劳寿命值不断降低,而喷管中前部的低周疲劳寿命值却不断提高,当冷却剂入口温度为280K左右时,本文的铣槽喷管总体使用寿命达到最大。      

BATHTUB-TYPE CURVES IN RELIABILITY AND BEYOND

Finding optimal, or at least good, maintenance and repair policies is crucial in reliability engineering. Likewise, describing life phases of human mortality is important when determining social policy or insurance premiums. In these tasks, one searches for distributions to fit data and then makes inferences about the population(s). In the present paper, we focus on bathtub‐type distributions and provide a view of certain problems, methods and solutions, and a few challenges, that can be encountered in reliability engineering, survival analysis, demography and actuarial science.     

荷兰居民生活质量调查方法研究及对中国的启示

通过对荷兰居民生活质量调查方法的研究，旨在分析总结其值得借鉴之处，并在此基础上针对中国正在探索中的居民生活质量调查，提出构建中国居民生活质量调查体系应拓宽其调查信息来源、实现数据共享、积极提高回应率、培养高素质调查队伍以及定期发布调查报告。     

后现代思潮中青年学子的生命教育

后现代思潮张扬＂颠覆＂和＂解构＂,宣扬＂边缘＂,追求＂另类＂,躲避＂崇高＂,倡导生活＂无厘头＂化。受其消极影响,一些青年学子失去了对生命存在的敬畏感,否定了生命延续的神圣意义,导致了一系列自杀、自残、施虐和杀人的极端行为发生。而当前我国高校中的生命教育却存在着教育体系不完善、教育方式不科学、教育内容缺乏针对性等不足。因此,在后现代思潮中应该有针对性地强化青年学子的生命意义教育：一是批判后现代思潮的虚妄性,教育青年学子正确认识历史和现实;二是尊重青年学子的个性差异,引导学子学会达成社会共识和担负生存责任;三是以马克思主义引导青年学子的＂三观＂成长,塑造青年学子正确的生命观。