On the Failure Probability of Used Coherent Systems

In analyzing the lifetime properties of a coherent system, the concept of “signature” is a useful tool. Let T be the lifetime of a coherent system having n iid components. The signature of the system is a probability vector s=(s₁, s₂, …, s_n), such that s_i=P(T=X_i:n), where, X_i:n, i=1, 2, …, n denote the ordered lifetimes of the components. In this note, we assume that the system is working at time t>0. We consider the conditional signature of the system as a vector in which the ith element is defined as p_i(t)=P(T=X_i:n|T>t) and investigate its properties as a function of time.     

On Estimating the Residual Rényi Entropy under Progressive Censoring

In this article, the residual Rényi entropy (RRE) as a measure of uncertainty is considered in progressively Type II censored samples and some properties of it are investigated. The RRE of sth order statistic from a continuous distribution function is represented in terms of the RRE of the sth order statistic from uniform distribution. In general, we do not have a closed form for RRE of order statistics in most of distributions. This gives us a motivation for obtaining some bounds for RRE in progressively censored samples. In addition, two estimators are proposed for RRE. The performance of these estimators is compared using simulation studies.     

Bivariate copulas on the Hotelling's T2 control chart

In this paper, we propose five types of copulas on the Hotelling's T² control chart when observations are from exponential distribution and use the Monte Carlo simulation to compare the performance of the control chart, which is based on the Average Run Length (ARL) for each copula. Five types of copulas function for specifying dependence between random variables are used and measured by Kendall's tau. The results show that the copula approach can be fitted the observation and we can use copula as an option for application on Hotelling's T² control chart.     

A new adaptive EWMA control chart using auxiliary information for monitoring the process mean

The adaptive memory-type control charts, including the adaptive exponentially weighted moving average (EWMA) and cumulative sum (CUSUM) charts, have gained considerable attention because of their excellent speed in providing overall good detection over a range of mean shift sizes. In this paper, we propose a new adaptive EWMA (AEWMA) chart using the auxiliary information for efficiently monitoring the infrequent changes in the process mean. The idea is to first estimate the unknown process mean shift using an auxiliary information based mean estimator, and then adaptively update the smoothing constant of the EWMA chart. Using extensive Monte Carlo simulations, the run length profiles of the AEWMA chart are computed and explored. The AEWMA chart is compared with the existing control charts, including the classical EWMA, CUSUM, synthetic EWMA and synthetic CUSUM charts, in terms of the run length characteristics. It turns out that the AEWMA chart performs uniformly better than these control charts when detecting a range of mean shift sizes. An illustrative example is also presented to demonstrate the working and implementation of the proposed and existing control charts.     

关于按揭购房柔性还贷的构想

等额本息还款法,等额本金还款法,等比累进还款法,等额累进还款法是国内外比较常见的按揭购房还贷计息方式。但每种还贷方式都规定贷款人必须在还款期限内的某个时刻向银行缴纳一定的还款额。在本金确定还贷方式确定的情况下该还款额是一个确定的数值,贷款人须按时向银行缴纳该数值的还款额而没有任何还款时间和数量上的柔性空间。根据技术经济学资金等值的概念,按揭购房柔性还贷的构想应该是可行的。     

A combined control scheme for monitoring the frequency and size of an attribute event

A traffic accident can be considered as an example of the attribute events, and the number of the injured in each accident is called the event size. Some control charts have been developed for monitoring either the time interval (T) between the occurrences of an event or the event size (C) in each occurrence. This article studies the statistical monitoring of the attribute events in which T and C are monitored simultaneously and C is an integer. Essentially, it integrates a T chart and a C chart, and is therefore referred to as a T&C scheme. Our studies show that the new chart is more effective than an individual T chart or C chart for detecting the out-of-control status of the event, in particular for detecting downward shifts (sparse occurrence and/or small size). Another desirable feature of the T&C scheme is that its detection effectiveness is more invariable against different types of shifts (i.e. T shift, C shift and joint shift in T&C) compared with an individual T or C chart. The improvement in performance is achieved due to the simultaneous monitoring of T and C. The T&C scheme can be applied in manufacturing systems and especially in non-manufacturing sectors (e.g. supply chain management, health care industry, disaster management and security control).     

A side sensitive modified group runs control chart to detect shifts in the process mean

Gadre and Rattihalli [5 Gadre, M. P. and Rattihalli, R. N. 2006. Modified group runs control charts to detect increases in fraction non-conforming and shifts in the process mean. Commun. Stat. Simul. Comput., 35: 225–240. [Taylor & Francis Online], [Web of Science ®] [Google Scholar]] have introduced the Modified Group Runs (MGR) control chart to identify the increases in fraction non-conforming and to detect shifts in the process mean. The MGR chart reduces the out-of-control average time-to-signal (ATS), as compared with most of the well-known control charts. In this article, we develop the Side Sensitive Modified Group Runs (SSMGR) chart to detect shifts in the process mean. With the help of numerical examples, it is illustrated that the SSMGR chart performs better than the Shewhart's X¯ chart, the synthetic chart [12 Wu, Z. and Spedding, T. A. 2000. A synthetic control chart for detecting small shifts in the process mean. J. Qual. Technol., 32: 32–38. [Taylor & Francis Online], [Web of Science ®] [Google Scholar]], the Group Runs chart [4 Gadre, M. P. and Rattihalli, R. N. 2004. A group runs control chart for detecting shifts in the process mean. Econ. Qual. Control, 19: 29–43. [Crossref] [Google Scholar]], the Side Sensitive Group Runs chart [6 Gadre, M. P. and Rattihalli, R. N. 2007. A side sensitive group runs control chart for detecting shifts in the process mean. Stat. Methods Appl., 16: 27–37. [Crossref], [Web of Science ®] [Google Scholar]], as well as the MGR chart [5 Gadre, M. P. and Rattihalli, R. N. 2006. Modified group runs control charts to detect increases in fraction non-conforming and shifts in the process mean. Commun. Stat. Simul. Comput., 35: 225–240. [Taylor & Francis Online], [Web of Science ®] [Google Scholar]]. In some situations it is also superior to the Cumulative Sum chart p9 Page, E. S. 1954. Continuous inspection schemes. Biometrika, 41: 100–114. [Crossref], [Web of Science ®] [Google Scholar]] and the exponentially weighed moving average chart [10 Roberts, S. W. 1959. Control chart tests based on geometric moving averages. Technometrics, 1: 239–250. [Taylor & Francis Online] [Google Scholar]]. In the steady state also, its performance is better than the above charts.     

Mean residual life ordering

A new partial ordering among life distributions in terms of their mean residual life is introduced. This ordering is weaker than the hazard rate ordering but it is stronger than the variability ordering. Characterizations of the DMRL and NBUE distribution are given.     

When social work students meet workers with mental-health lived-experience: a case study

Current social work education in India reflects globalization priorities and tendencies of neo-colonialism that emulate curriculum priorities and duplicate content developed in countries like the USA. Social work education as implemented by countries like the USA, has limited success in transnational training of social workers and their ability to address emerging social problems and deep rooted structural imbalances within non-USA social contexts. Yet, the concept of the world being an emerging global village is used to justify and reaffirm the colonial goals of universal education and pedagogies within social work and its application to starkly different contexts, such as India. This paper argues against the imperialist nature of social work education through examples from social work syllabi from Indian schools of social work. Secondly, this paper examines the role of academic collaborations and international organizations in addressing the challenges in curriculum development. Finally, through an example from a Curriculum Development Project undertaken in a sub-Saharan African country by one of the authors, the paper demonstrates ways of generating more local content for curricula that would create culturally sensitive social services.     

图谱类文献在南宋目录学中的定位及其影响

中国古代目录学的研究对象,大多是以文字写成,用于明理、叙事、抒情之＂书＂,而很少涉及以直观、简明为形式特点的＂图＂和＂谱＂。在目录学史中,图谱类文献时隐时显,合而复分,总体上可分为三个发展阶段：南宋前,《七志》确立＂图谱志＂,而《七录》分散图谱、各归部类,是第一阶段;南宋时,从郑樵《通志》对图谱功能、地位的理论建设,到尤袤《遂初堂书目》去＂图＂留＂谱＂,设立＂谱录类＂,是第二阶段;南宋后,特别是清代以降,图学和谱录分道扬镳,各立门户,是第三阶段。这三个阶段中,南宋时期图谱类文献得到的理论关注和转型发展,最为关键。研究这一问题,可以深入认识此类文献的特点和功能,以一个特殊的角度了解不同时代、不同学者在目录学分类原则上的差异。同时,古人对图谱的理论阐释,会为当今处于＂读图时代＂的读者和学人,提供有益的启示和借鉴。