Availability analysis for general repairable systems with repair time threshold

Availability analysis is an important issue in many practical fields. This paper investigates the availability for general repairable systems with repair time threshold. Based on practical applications, a repair time threshold is introduced. If the period of a repair is less than a predefined time threshold, then the system may be considered as working during this period, i.e., the effect of the repair could be neglected. Otherwise, if the period of a repair is longer than the given threshold, then the system is considered as working from the beginning of the system failure until the repair time exceeding the threshold, i.e., the time point of the system down could be delayed. We consider both constant and random repair time threshold. This paper valuates the user-perceived availability, when the user does not experience any service interruption because the duration of repair is too short. The results can be applied in reliability engineering, queueing theory and many other fields. A numerical example for ventilator system is presented to demonstrate the application of the developed approach.     

A Study on Reliability for A Two-Item Cold Standby Markov Repairable System with Neglected Failures

This article studies reliability for a Markov repairable two-item cold standby system with neglected failures. In the system, if a failed time of the system is too short (less than a given critical value) to cause the system to fail, then the failed time may be omitted from the downtime record, i.e., the failure effect could be neglected. In ion-channel modeling, this situation is called the time interval omission problem. The availability indices and the mean downtime are presented as two measures of reliability for this repairable system. Some numerical examples are shown to illustrate the results obtained in this article.     

中国会计制度改革及其主要变化

1992～ 1993年 ,中国进行了重大财务制度改革 ,以《企业会计准则一基本准则》和《企业财务通则》 ,以及 13项行业财务制度、10项行业会计制度 (以下简称“两则两制”)的发布为标志 ,初步建立了资产、负债、所有者权益、收入、费用和利润六大会计要素 ,实现了我国会计核算模式的转换 ,为企业引进外资 ,走出国门奠定了财务会计基础。经过近十年的运作 ,这套财务制度已经得到基本贯彻 ,在现实管理中起到良好作用 ,为进一步的会计改革奠定了基础。面对国际环境的快速变化 ,以及中国加入ＷＴＯ后将迅速融入经济全球化的现实要求 ,上述经初步改革…     

Some aspects of the mean past lifetime of a parallel system under double regularly checking

In this paper, a parallel system consisting of a finite number of identical components with independent lifetimes having a common distribution function is considered, when the failure time of the system is restricted to a finite interval (double regularly checking). Under these conditions, the mean past lifetime (MPL) of the system is presented and some of its properties are derived. It is shown that the underlying distribution function can be recovered from the proposed MPL. Then, a consistent estimator for MPL is presented and some of its properties are studied. This estimator also could be used for the single monitoring case or ordinary MPL. Finally, some properties of the MPL of a parallel system with nonidentical components are discussed.     

Bayesian analysis of competing risks with partially masked cause of failure

Summary. Bayesian analysis of system failure data from engineering applications under a competing risks framework is considered when the cause of failure may not have been exactly identified but has only been narrowed down to a subset of all potential risks. In statistical literature, such data are termed masked failure data. In addition to masking, failure times could be right censored owing to the removal of prototypes at a prespecified time or could be interval censored in the case of periodically acquired readings. In this setting, a general Bayesian formulation is investigated that includes most commonly used parametric lifetime distributions and that is sufficiently flexible to handle complex forms of censoring. The methodology is illustrated in two engineering applications with a special focus on model comparison issues.     

社会资本与我国经济和谐发展

摘　　要:社会资本可以降低交易成本,提高经济活动的效率。本文将社会资本引入投资模型和市场经济发展的均衡模型,构建了社会资本-交易成本-市场经济发展的研究框架和研究模型,实证检验了社会资本对我国市场经济发展的重要作用。教育水平和法律体制的效率作为制度背景变量也被引入模型。模型预测社会资本、法律体制效率和教育水平与市场经济发展正相关     

影响中国城乡收入差距的制度系统分析——基于1983-2009年中国城乡收入差距和人均GDP数据

伴随中国经济高速增长的是城乡收入差距的不断扩大,制度是其重要根源。在公平与效率的目标下构建Logistics制度系统演化模型,城乡收入差距和人均GDP数据分别代表公平与效率,对所构建模型进行拟合,验证了公平与效率的交叉影响。利用1983-1997年和1997-2009年数据分别进行拟合,通过对比两个时间段制度系统参数和均衡点的估计值,发现前一个时期的制度系统要优于后一个。所以,缩小城乡收入差距的制度改革如果能够对制度系统均衡点作出调整,就更加合理。     

Shipman's statistical legacy

Harold Shipman, who in January committed suicide in prison, has become notorious the world over as one of the most prolific serial killers of all time. His case has also seriously dented public confidence in doctors. David Spiegelhalter and Nicky Best explain how industrial quality control techniques could be adapted to signal when death rates among a doctor's patients are surprisingly high, and the tricky issues that would arise in implementing such a monitoring system.     

基于云理论的高校职员绩效评价研究

职员的绩效评估是企事业单位人事考核的重要组成部分。在高等院校职员的评价体系中存在大量的定性描述指标,如何科学地实现定性指标向定量指标的转换,是使评估更加准确、科学的重要因素。云理论是在对传统模糊集理论和概率论进行交叉渗透的基础上,形成自然语言值表示的某个定性概念与其定量表示之间的转换模型。本文将云重心评价法引入到高校职员绩效评估方法中,建立了高校职员绩效评价体系,并通过实例,证明了运用该方法能方便有效地解决高校职员绩效评价中的指标转换问题。     

The use of semantic knowledge to enhance statistical software

The shortcomings of conventional statistical packages are discussed to illustrate the need to develop software which is able to exhibit a greater degree of statistical expertise, thereby reducing the misuse of statistical methods by those not well versed in the art of statistical analysis. Up to now the majority of the research into developing knowledge-based statistical software has concentrated on moving away from conventional architectures by adopting what can be termed expert systems approaches. This paper proposes an approach which is based upon the concept of semantic modelling. By representing some of the semantic meaning of data, it is conceived that a system could examine a request to apply a statistical technique and check if the use of the chosen technique was semantically sound, i.e. will the results obtained be meaningful. Current systems, in contrast, can only perform what can be considered as syntactic checks. The prototype system that has been implemented to explore the feasibility of such an approach is presented; the system has been designed as an enhanced variant of a conventional style statistical package.     

ANALYSIS OF A GI/G Y /1 SYSTEM IN DISCRETE-TIME

ABSTRACT

We consider a class of single server queueing systems in which customers arrive singly and service is provided in batches, depending on the number of customers waiting when the server becomes free. Service is independent of the batch size. This system could also be considered as a batch service queue in which a server visits the queue at arbitrary times and collects a batch of waiting customers for service, or waits for a customer to arrive if there are no waiting customers. A waiting server immediately collects and processes the first arriving customer. The system is considered in discrete time. The interarrival times of customers and the inter-visit times of the server, which we call the service time, have general distributions and are represented as remaining time Markov chains. We analyze this system using the matrix-geometric method and show that the resulting R matrix can be determined explicitly in some special cases and the stationary distributions are known semi-explicitly in some other special cases.     

县域城乡居民消费结构与收入关系分析

 本文利用福建省县域居民消费样本调查数据,基于空间相关性和扩展线性支出系统,对我国县域居民消费结构与收入关系进行实证分析。结果表明：可支配(纯)收入对居民的各类消费具有显著的影响,而且对八类消费的作用强度不同;旨在提高居民收入的收入分配制度改革能够促进消费需求,针对不同边际消费倾向的政策可以更有效地引导居民消费。本文的分析不同于以往对居民消费结构的研究在于：一是直接使用居民生活状况调查的微观数据进行ELES模型的参数估计,改变了仅使用七类收入群体数据的局限;二是在ELES模型中引入空间因素,考虑了因地理相邻对居民消费结构的影响,分析更为客观合理。     

Improving the contributions of technology assessment to the health care system of the U.S.A.

Summary Based on 14 case studies of highly effective therapies and the reasons they succeeded less frequently than they could, we propose a variety of steps to improve the health care system of the U.S.A. Whatever proposal emerges from current national debates until innovations are shown to be safe and effective, they should not be supported; when slightly better technologies are much more expensive than other good ones we need to consider appropriate choices carefully; simplified billing and bookkeping would reduce our costs; when a technology is rapidly introduced cautionnary measures may be needed; tracking immunization and repairing their omissions requires a new system; educational programs such as seen effective in hypertension should be applied in other areas such as vaccination; in organ transplantation the nation should consider “presumed consent”; our payment system sometimes creates perverse incentives and therefore needs review; and the preferences of the public in allocation of health resources need to be discovered once the public is informed about the issues. Research supported by Andrew W. Mellon Foundation.     

灰色斜率相似关联度研究及其应用

根据灰色关联分析的基本思想,基于灰色斜率关联度的计算模型,提出了一种新的灰色斜率相似关联度计算模型,它满足相似性。该计算模型充分利用了序列在各个时点的信息和正、负相关性,得出的关联分析结果比较客观可靠。实例分析表明：该模型简单,且具有良好的应用性。     

中央及地方财政格局下公路收费的影响、成因及对策

本文采用混合组平均（PMG）及广义矩估计（GMM）方法实证检验了当前公路收费制度对我国经济发展的影响并探索其作用机制。我们发现过高收费水平已经不利于经济增长：收费水平每提高1%会导致GDP增长率放缓0.005%、人均GDP降低0.04%。由此计算出该制度在2012年新增社会经济成本约为1660亿元,大于其收益。该制度的作用机制通过促进路网建设、降低国内贸易总量及市场整合程度两个相反作用实现。本研究将高收费归咎于分税制改革之后地方预算内财力的不足。这些发现为政策制定者改革该制度提供了必要的参考：中央财政应加大在路网建设中的作用,同时通过预算内转移支付的方式补偿改革过程中地方政府的损失。     

Markov Systems in a General State Space

In this article, we introduce and study Markov systems on general spaces (MSGS) as a first step of an entire theory on the subject. Also, all the concepts and basic results needed for this scope are given and analyzed. This could be thought of as an extension of the theory of a non homogeneous Markov system (NHMS) and that of a non homogeneous semi-Markov system on countable spaces, which has realized an interesting growth in the last thirty years. In addition, we study the asymptotic behaviour or ergodicity of Markov systems on general state spaces. The problem of asymptotic behaviour of Markov chains has been central for finite or countable spaces since the foundation of the subject. It has also been basic in the theory of NHMS and NHSMS. Two basic theorems are provided in answering the important problem of the asymptotic distribution of the population of the memberships of a Markov system that lives in the general space (X, ?(X)). Finally, we study the total variability from the invariant measure of the Markov system given that there exists an asymptotic behaviour. We prove a theorem which states that the total variation is finite. This problem is known also as the coupling problem.     

Third order point process intensity estimation for reaction time experiment data

The authors consider a simple parametric model for data from a point process version of a reaction time experiment to test the nature of thinning mechanisms in the presence of nonlinear inhibition in the eye‐brain‐hand system. In particular, they study the effects of two such mechanisms on the third order intensity estimate. An alternative nonparametric estimate is also considered in this context. These various approaches are applied on twelve runs of real data, but the analysis turns out to be inconclusive: neither mechanism can be ruled out, nor the possibility that their effects could be combined.     

Optimal Maintenance Time for Repairable Systems Under Two Types of Failures

Determination of preventive maintenance is an important issue for systems under degradation. A typical maintenance policy calls for complete preventive repair actions at pre-scheduled times and minimal repair actions whenever a failure occurs. Under minimal repair, failures are modeled according to a non homogeneous Poisson process. A perfect preventive maintenance restores the system to the as good as new condition. The motivation for this article was a maintenance data set related to power switch disconnectors. Two different types of failures could be observed for these systems according to their causes. The major difference between these types of failures is their costs. Assuming that the system will be in operation for an infinite time, we find the expected cost per unit of time for each preventive maintenance policy and hence obtain the optimal strategy as a function of the processes intensities. Assuming a parametrical form for the intensity function, large sample estimates for the optimal maintenance check points are obtained and discussed.     

论股息收益率指标在我国证券市场中的运用

从目前的现状看,我国上市公司与成熟资本市场相比存在现金分红普遍偏低的问题,运用股息收益率指标分析股票内在投资价值的策略在我国证券市场上还不是很广泛,这使市场的投机行为不能得到很好的控制。本文分析了股息收益率指标的优点,提出建立股息收益率为核心的股价评估体系,从而树立理性价值投资理念的可行性。     

EXPLORA:content interpretation of data

Most approaches to applying knowledge-based techniques for data analyses concentrate on the context-independent statistical support. EXPLORA however is developed for the subject-specific interpretation with regard to the contents of the data to be analyzed (i.e. content interpretation). Therefore its knowledge base includes also the objects and semantic relations of the real system that produces the data. In this paper we describe the functional model representing the process of content interpretation, summarize the software architecture of the system and give some examples of its applications by pilot-users in survey analysis. EXPLORA addresses applications with data produced regularly which have to be analyzed in a routine way. The system systematically searches for statistical results (facts) to detect relations which possibly could be overlooked by a human analyst. On the other hand EXPLORA will help overcome the large bulk of information which today is usually still produced when presenting the data. Therefore a second knowledge process of content interpretation consists in discovering messages about the data by condensing the facts. Approaches for inductive generalization which have been developed for machine learning are utilized to identify common values of attributes of the objects to which the facts relate. At a later stage the system searches for interesting facts by applying redundancy rules and domaindependent selection rules. EXPLORA formulates the messages in terms of the domain, groups and orders them and even provides flexible navigations in the fact spaces.