Accurate computation of single and product moments of order statistics under progressive censoring

An accurate procedure is proposed to calculate approximate moments of progressive order statistics in the context of statistical inference for lifetime models. The study analyses the performance of power series expansion to approximate the moments for location and scale distributions with high precision and smaller deviations with respect to the exact values. A comparative analysis between exact and approximate methods is shown using some tables and figures. The different approximations are applied in two situations. First, we consider the problem of computing the large sample variance–covariance matrix of maximum likelihood estimators. We also use the approximations to obtain progressively censored sampling plans for log-normal distributed data. These problems illustrate that the presented procedure is highly useful to compute the moments with precision for numerous censoring patterns and, in many cases, is the only valid method because the exact calculation may not be applicable.     

Ordering results for series and parallel systems comprising heterogeneous exponentiated Weibull components

In this paper, we discuss the usual stochastic and reversed hazard rate orders between the series and parallel systems from two sets of independent heterogeneous exponentiated Weibull components. We also obtain the results concerning the convex transform orders between parallel systems and obtain necessary and sufficient conditions under which the dispersive and usual stochastic orders, and the right spread and increasing convex orders between the lifetimes of the two systems are equivalent. Finally, in the multiple-outlier exponentiated Weibull models, based on weak majorization and p-larger orders between the vectors of scale and shape parameters, some characterization results for comparing the lifetimes of parallel and series systems are also established, respectively. The results of this paper can be used in practical situations to find various bounds for the important aging characteristics of these systems.     

Prediction of future failures times based on Type-I hybrid censored samples of random sample sizes

In this article, we consider the prediction of future failure times based on Type-I hybrid censored samples. Point predictors and prediction intervals using different procedures are discussed for a general model. The exponential and Rayleigh distributions are used as illustrative examples to show the most simplified forms of the so obtained predictors as well as prediction intervals. Intensive simulation study and a real life dataset are presented to illustrate our findings and results.     

Depoliticising literature,politicising diversity: ethno-racial boundaries in Dutch literary professionals’ aesthetic repertoires

Although still a neglected area, over the years a growing body of sociological research on the position of ethno-racial minorities in Western artistic fields has emerged. With this article we aim to contribute to this research area by focusing on ethno-racial diversity in the Dutch literary field. Through in-depth interviews, we analyse how gatekeepers mobilise specific cultural repertoires and by doing so draw ethno-racial boundaries when discussing acquisition, assessing quality and positioning themselves in the literary field. We argue that literary publishers and other professionals (selectively) employ an ‘old school’ modernist repertoire that especially values the formal aspects of literary products, by which non-white writers and publishers concerned with diversity are often positioned in an identity politics framework. Their work is said to take in a less prestigious ‘political’/’subjective’ position rather than a ‘literary’/‘universal’ one. As such, this paper informs on how gatekeepers’ practices shape the position of non-white authors in the Dutch literary field.     

Elementary School-age Children's Attitudes Toward Children in Same-Sex Parent Families

As numbers of families with same-sex parents increase in the United States, children are more likely to encounter diverse family structures. Given that young children can demonstrate in-group bias, prejudicial attitudes, and social exclusion, it is important to understand how children perceive their peers in diverse families. To our knowledge, no studies have assessed elementary-school-age children's attitudes about same-sex parent families. Here, 131 elementary school students (M_age = 7.79 years; 61 girls) viewed images of same-sex (female and male) and other-sex couples with a child and then were asked about their perceptions of these families, particularly the children. Results indicated participants' preferences toward children with other-sex versus same-sex parents. Developmental and practical implications about children's attitudes toward sexual minority parent families are discussed.     

Parents’ perspectives of social support and social cohesion in urban contexts of diversity

Although provisions for young children are increasingly considered as ideal places to foster an inclusive and socially just society by embracing issues of social support and social cohesion, there is no in-depth understanding of the role these provisions can play in enabling supportive and cohesive encounters in contexts of diversity. Even more striking is the absence of parents’ voices in this discussion. Based on an analysis of qualitative interviews with 18 parents who use childcare services in urban contexts of diversity, our findings show the relevance of ephemeral contacts with diverse people that could offer bridging opportunities in terms of social connectedness to familiarise within diversity while decoding the other in urban contexts of diversity. However, neither bonding nor bridging contacts appear as self-evident. Our research shows that the role of childcare services might be vital in creating light and temporal communities as the prerequisite for social cohesion to flourish, in both individual as well as collective dimensions.     

《民族学刊》2014~2018年影响因子比较分析——基于《中国学术期刊影响因子年报（人文社会科学）》数据

《民族学刊》于2010年6月创刊,相继入选“复印报刊资料重要转载来源期刊”“北大核心期刊”“人文社科核心期刊”和“CSSCI来源期刊”,表明了《民族学刊》在学界和期刊界的学术影响,其期刊的影响因子值得研究和探讨。本文基于《中国学术期刊影响因子年报（人文社会科学）》公布的影响因子、各类计量指标和人文社科类影响因子、被引频次及可被引文献量等数据,对《民族学刊》的相应数据与C95民族学类期刊在期刊影响力指数、影响因子均值及量效指数均值、各类计量指标均值和人文社科类影响因子、被引频次及可被引文献量均值等方面进行统计对比,分析《民族学刊》2014~2018年五年间的影响因子数据在民族学类期刊位置及其学术影响。     

文化多样性研究述评

文化多样性是当前学术界研究的前沿问题。本文以国内外学者关于文化多样性的研究文献为基础,对文化多样性的形成与影响、文化的发展方向、文化多样性的保护等方面进行总结和回顾。     

基于遗传算法的进化支持向量机研究

支持向量机是最近发展起来的一种新的通用的机器学习方法 ,其理论基础是统计学习理论 ,支持向量机无论在模式识别还是在函数拟合方面均显示了其优越性 ,并越来越受到国内外研究者的广泛关注 .但是 ,对支持向量机的推广预测能力具有很大影响的核函数和参数C一直没有一个很好的确定方法 ,针对这一问题 ,将遗传算法和支持向量机结合 ,提出了一种自动选择支持向量机参数的方法 ,结果表明 ,这种方法是科学有效的 .     

学校乒乓球业余训练的研究

乒乓球运动需要人才辈出。“塔基”式的人才培养是在众多的基层单位有组织管理的全民健身运动活动中形成和发展起来的。学校开展业余训练工作 ,需要在完成教学工作量的前提下 ,利用课余时间、两个假期以及双休日有目的地培养和发现有潜力的运动员人才。培训过程需要专业性、系统性和长期性 ,这样做有利于少儿运动员身心健康成长 ,有利于基本功形成专业化 ,并且能够活跃校园体育文化活动。同时 ,业余训练能够出成绩 ,能够参加各级各类比赛活动