Optimal step-stress testing for progressively Type-I censored data from exponential distribution

In this paper, a k  -step-stress accelerated life-testing is considered with an equal step duration τ$\tau$. For small to moderate sample sizes, a practical modification is made to the model previously considered by Gouno et al. [2004. Optimal step-stress test under progressive Type-I censoring. IEEE Trans. Reliability 53, 383–393] in order to guarantee a feasible k  -step-stress test under progressive Type-I censoring, and the optimal τ$\tau$ is determined under this model. Next, we discuss the determination of optimal τ$\tau$ under the condition that the step-stress test proceeds to the k  -th stress level, and the efficiency of this conditional inference is compared to that of the previous case. In all cases considered, censoring is allowed at each point of stress change (viz., iτ$i\tau$, i=1,2,…,k$i=1,2,\dots ,k$). The determination of optimal τ$\tau$ is discussed under C-optimality, D-optimality, and A-optimality criteria. We investigate in detail the case of progressively Type-I right censored data from an exponential distribution with a single stress variable.     

Confidence limits and prediction limits for a Weibull distribution based on the generalized variable approach

In this article, we consider the problems of constructing confidence interval for a Weibull mean and setting prediction limits for future samples. Specifically, we construct upper prediction limits that include at least l$l$ of m$m$ samples from a Weibull distribution at each of r$r$ locations. The methods are based on the concept of generalized variable approach. The procedures can be easily extended to the type II censored samples, and they can be used to find approximate inferential procedures for type I censored samples. The proposed methods are conceptually simple and easy to use. The results are illustrated using some practical examples.     

原生态智慧的“他者”想像与文化多样性

现代背景下环境问题日益突出,原生态智慧成为当前研究较多的一个主题.原生态智慧的神话其实是"他者"与"我者"合谋的产物,通过"他者"想像得以构建.但"他者"的智慧同样可以为"我者"的前行提供参考,而通过"他者"与"我者"的互渗来保持文化多样性,不失为一条可选择的较为可靠的道路.     

Identity,accent aim,and motivation in second language users: New Scottish Gaelic speakers’ use of phonetic variation

This paper examines the use of phonetic variation in word‐final rhotics among nineteen adult new speakers of Scottish Gaelic, i.e. speakers who did not acquire the language through intergenerational transmission. Our speakers learned Gaelic as adults and are now highly advanced users of the language. We consider variation in their rhotic productions compared to the productions of six older, traditional speakers. Previous approaches to variation in second language users have either focussed on how variable production will eventually result in native‐like ‘target’ forms (Type 1 study), or have investigated the extent to which second language users reproduce patterns of variation similar to ‘native speakers’ (Type 2 study). We additionally draw on sociocultural approaches to Second Language Acquisition and apply notions of accent aim, identity construction, and learning motivation in order to fully explore the data. In doing so, we advocate a ‘Type 3’ approach to variation in second language users.     

Education and income inequality: The role of a social protection system

In this paper we aim to understand the role a welfare state can play in stimulating risky but profitable activities like investment in education, and in reducing income inequality. We analyze how unemployment benefits may affect investment in education when the latter is characterized by uncertain returns. This is done in an overlapping generations model in which endogenous growth is introduced through human capital accumulation. We develop a numerical example of the model in order to reproduce some key differences between the European versus the North American economy; differences that, according to this model, result from the different degree of social protection characterizing both economies. Received: 02 June 1999/Accepted: 22 February 2000     

意识有什么世界就有什么

哲学的现代转向是从世界形而上学转向意识形而上学,产生了探究意识的先验论哲学。先验论意识哲学经历了从笛卡尔到康德再到胡塞尔的三次里程碑式的问题推进:笛卡尔力图证明意识是理解一切问题的唯一可靠出发点;康德力图证明意识具备构造有效知识的能力,并且证明意识具备指导正当行为的能力;胡塞尔则力图证明意识内在地拥有完整的客观对象,相当于拥有属于意识自己的世界。经过这三次伟大而艰巨的努力,先验论意识哲学完成了求证我思和所思的唯心论论证,特别是关于内置于主观性的客观性的论证。但是从根本上说,先验论意识哲学的这些工作只是辩护性的,仍然没有达到奠基性的论证,因此仍然对世界无所解释。     

Breastfeeding practices in women with type 1 diabetes: A discussion of the psychosocial factors and policies in Sweden and Australia

BackgroundWomen with type 1 diabetes (T1DM) face many challenges during their pregnancy, birth and in the postnatal period, including breastfeeding initiation and continuation while maintaining stable glycaemic control. In both Sweden and Australia the rates of breastfeeding initiation are high. However, overall there is limited information about the breastfeeding practices of women with T1DM and the factors affecting them. Similarities in demographics, birth rates and health systems create bases for discussion.AimThe aim of this paper is to discuss psychosocial factors, policies and practices that impact on the breastfeeding practices of women with T1DM.FindingsSwedish research indicates that the overall breastfeeding rate in women with T1DM remains significantly lower than in women without diabetes in the first 2 and 6 months after childbirth with no differences in exclusive breastfeeding. Breastfeeding initiation and continuation among women with T1DM in Sweden has been shown to be influenced by health services delivery, supportive breastfeeding polices and socio-economic factors, particular perceived support from social networks and health professionals.ConclusionThere is limited research on the impact of attitudes towards breastfeeding, emotional and social well-being and diabetes-related stress on the decision of women with T1DM to initiate and continue to breastfeed for at least 6 months. A more comprehensive understanding of the breastfeeding practices and psychosocial factors operating during the first 6 months after birth for women with T1DM will be instrumental in the future design of interventions promoting initiation and continuation of breastfeeding in Sweden, Australia and elsewhere.     

中国现代故事学的滥觞——20世纪二三十年代故事学成就评述

初期的现代故事学在三个方面取得了引人注目的成就:首先,建立了中国民间故事体裁学;其次,初步编制出民间故事分类体系;再次,受进化论影响,运用历史地理学派分析方法,深入讨论了民间故事演进状态。这些成就给后来的研究工作奠定了坚实的理论和实践基础。     

Imposing the Regular Ultra Passum law in DEA models

Recently there has been some discussion in the literature concerning the nature of scale properties in the Data Envelopment Model (DEA). It has been argued that DEA may not be able to provide reliable estimates of the optimal scale size. We argue in this paper that DEA is well suited to estimate optimal scale size, if DEA is augmented with two additional maintained hypotheses which imply that the DEA-frontier is consistent with smooth curves along rays in input and in output space that obey the Regular Ultra Passum (RUP) law, i.e. monotonically decreasing scale elasticities. A necessary condition for a smooth curve passing through all vertices to obey the RUP-law is presented. If this condition is satisfied then upper and lower bounds for the marginal product at each vertex are presented. It is shown that any set of feasible marginal products will correspond to a smooth curve passing through all points with a monotonic decreasing scale elasticity. The proof is constructive in the sense that an estimator of the curve is provided with the desired properties. A typical DEA based return to scale analysis simply reports whether or not a DMU is at the optimal scale based on point estimates of scale efficiency. A contribution of this paper is that we provide a method which allows us to determine in what interval optimal scale is located.     

E-Bayesian estimation for the proportional hazard rate model based on record values

In this article, a new parameter estimation method, named E-Bayesian method, is considered to obtain the estimates of the unknown parameter and reliability function based on record values. The maximum likelihood, Bayesian, E-Bayesian, and hierarchical Bayesian estimates of the unknown parameter and reliability function are obtained when the underlying distribution belongs to the proportional hazard rate model. The Bayesian estimates are obtained based on squared error and linear-exponential loss functions. The previously obtained some relations for the E-Bayesian estimates are improved. The relationship between E-Bayesian and hierarchical Bayesian estimations are obtained under the same loss functions. The comparison of the derived estimates are carried out by using Monte Carlo simulations. Real data are analyzed for an illustration of the findings.