Accelerated Burn-In Procedures and System Maintenance Policies

Burn-in is a widely used engineering method which is adopted to eliminate defective items before they are shipped to customers or put into field operation. In order to shorten the burn-in process, burn-in is most often accomplished in an accelerated environment. However, there have been few probabilistic or stochastic models for the burn-in procedures in accelerated environment. In this article, under a new stochastic model for accelerated burn-in procedure, the problems of determining both optimal accelerated burn-in time and optimal replacement policy are considered. Components are burned-in under an accelerated environment, then those surviving the burn-in procedure are put into field operation and they are maintained under a replacement policy. The properties of the optimal accelerated burn-in time and optimal replacement policy are obtained and a numerical example which illustrates the usage of obtained results will be presented.     

专家系统与过程控制系统的整体式集成方法研究

本文对专家系统与传统过程控制系统的集成方法进行了系统的研究与分析，提出了递阶式集成方法和实施框架，该方法通过面向对的递阶建模方法将启发式知识和基于模型的知识按照工厂的递阶结构组织成类层次的，实现了多种类型知识的有效集成。     

Analysis of reliability characteristics in the acceptance sampling tests

Until now, various acceptance reliability sampling plans have been developed based on different life tests of items. However, the statistical effect of the acceptance sampling tests on the reliability characteristic of the lots accepted in the test has not been appropriately addressed. In this paper, we deal with an acceptance reliability sampling plan under a ‘general framework’ and discuss the corresponding statistical effect of the acceptance sampling tests. The lifetime of the population before the acceptance test and that of population ‘conditional on the acceptance’ in the sampling test are stochastically compared. The improvement of reliability characteristics of the population conditional on the acceptance in the sampling test is precisely analyzed.     

Burn-in for Eliminating Weak Items in Heterogeneous Populations

Burn-in is a method of eliminating early failures in populations of manufactured items. To burn-in a component or a system means to subject it to a ‘‘simulated operation’’ for some time (prior to its actual field use). Various optimal burn-in problems have been intensively studied in the literature under the assumption of decreasing or bathtub-shaped failure rates. However, most of these studies have been conducted for homogeneous populations. In this paper, we discuss burn-in for heterogeneous populations and develop approaches that minimize the risks of selecting items with large levels of individual failure rates. Using simple examples, we consider the optimal burn-in time, which minimizes these risks.     

关于强化社会遗属保障的探讨

我国现行遗属补助制度框架陈旧,碎片化严重,并且支付标准偏低,不能满足经济社会发展需要和难以实现抵御经济风险的目的。因此有必要将遗属保障社会化,建立社会遗属保险制度。结合我国实际分析,遗属保险制度是具有可行性的:在微观层面上可以操作,在宏观层面与我国经济社会发展水平相适应。     

大学生在高校教学质量管理中的主体地位和作用

教师授课质量是影响大学生学习主体性的主要因素 ,大学生参与教学管理有助于提高教师授课质量 ,参与的核心环节包括教学评价、方法研讨和课程优化。学生参与教学质量管理 ,必须以转变观念为先导、以政策和制度为保障、以组织建设抓落实。     

《焦仲卿妻》中之"东南"考辨

《焦仲卿妻》中的“东南”并非表示确切地理位置的方位词,而是特殊的艺术“东”、“南”分别同八卦中的“震”、“离”;家庭成员中的“长男”、“中女”;四季中的“春”、“夏”;五行中的“木”、“火”;五色中的“青”、“赤”和 五味中的 “酸”“苦”形成了对应关系。“东南”既象征着爱情婚姻,又象征着痛苦哀愁。《焦仲卿妻》以“东南”意象起兴和作结,奠定和强化了该诗赋艳和悲剧的色彩,产生了爱情悲剧的震撼力。     

Gender Difference in Sleep Problems: Focused on Time Use in Daily Life of Korea

Korea is well-known as one of the most sleepless country on the globe. Given the fact that sleep is closely connected with various health outcomes, we examined which group is more likely to experience sleep disorder problems within the context of time use. This study sets out to describe the differences in sleep disorder patterns between Korean men and women. In this study, we also tried to identify important socio-demoraphic factors and wake activity time use factors that might account for the sleep problem (short sleep/oversleep) and gender differences in sleep. Data from the original 2004 Korean Time Use Survey were used for this study (n = 16,958). Fifty-two percent of the respondents were women; the age range of the sample was 25–59 years. Results showed us that there was no gender differences found in dimension of short sleep. Still, women were less likely to be over sleeper rather than men, implying the existence of gender inequality in rest/free time. Results from the multinomial regression model showed that, although there were similarities in the impact of relevant factors, men’s sleep was more likely to be disturbed by their work role, while women’s sleep was affected by their work and family role. In this study, it was found that the gender difference in sleep problems was associated with time use, and especially the social roles that men and women occupied.     

Accelerated Life Test Data Analysis for Repairable Systems

In this article, the imperfect maintenance model and proportional intensity model are used to analyze failure data of repairable systems in accelerated life testing. In the design and development phase of products, we should collect and analyze failure data quickly with small proto-type products. Thus, we test the products under accelerated conditions and if the products fail, then we repair and use those continuously in the life testing. Acceleration and repair models are needed to analyze the failure data. An age reduction model (Brown et al.'s Brown et al. 1983 Brown , J. F. , Mahoney , J. F. , Sivazlian , B. D. ( 1983 ). Hysteresis repair in discounted replacement problems . IIE Trans. 15 : 156 – 165 . [CSA] [Taylor & Francis Online], [Web of Science ®] , [Google Scholar], model) and relationship between scale parameter and stress level are assumed. The stress acts multiplicatively on the baseline cumulative intensity. The maximum likelihood method is used, the log-likelihood function is derived, and a maximizing procedure is proposed. In simulation studies, we investigate the accuracy and trends of the maximum likelihood estimator.     

一种扩频PN码的混合同步系统

提出一种１０２４位码长，混合使用ＳＡＷ．ＭＦ与延时锁定环技术的扩频ＰＮ码同步方案，适用于长码、需快速同步的场合，文中对其工作原理作了介绍，并对其同步时间性能作了分析。