Nonparametric density estimation from censored data

Nonparametric estimation of the probability density function f° of a lifetime distribution based on arbitrarily right-censor-ed observations from f° has been studied extensively in recent years. In this paper the density estimators from censored data that have been obtained to date are outlined. Histogram, kernel-type, maximum likelihood, series-type, and Bayesian nonparametric estimators are included. Since estimation of the hazard rate function can be considered as giving a density estimate, all known results concerning nonparametric hazard rate estimation from censored samples are also briefly mentioned.     

Stochastic properties of conditionally independent mixture models

This paper deals with aging properties and stochastic comparisons of multivariate mixture models, having conditionally independent marginal distributions.     

Quantile-based Chernoff distance for truncated random variables

Several probability distributions such as power-Pareto distribution (see Gilchrist 2000 Gilchrist, W. 2000. Statistical modelling with quantile functions. Boca Raton, FL: Chapman and Hall/CRC.[Crossref] , [Google Scholar] and Hankin and Lee 2006 Hankin, R. K. S., and A. Lee. 2006. A new family of non-negative distributions. Australian and New Zealand Journal of Statistics 48:67–78.[Crossref], [Web of Science ®] , [Google Scholar]), various forms of lambda distributions (see Ramberg and Schmeiser 1974 Ramberg, J. S., and B. W. Schmeiser. 1974. An appropriate method for generating asymmetric random variables. Communications of the ACM 17:78–82.[Crossref], [Web of Science ®] , [Google Scholar] and Freimer et al. 1988 Freimer, M., S. Mudholkar, G. Kollia, and C. T. Lin. 1988. A study of the generalized lambda family. Communications in Statistics - Theory and Methods 17:3547–67.[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]), Govindarajulu distribution (see Nair, Sankaran, and Vineshkumar 2012 Nair, U. N., P. G. Sankaran, and B. Vineshkumar. 2012. The Govindarajulu distribution: some properties and applications. Communications in Statistics—Theory and Methods 41:4391–406.[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]), etc., do not have manageable distribution functions, though they have tractable quantile functions. Hence, analytical study of the properties of Chernoff distance of two random variables associated with these distributions via traditional distribution function-based tool becomes difficult. To make this simple, in this paper, we introduce quantile-based Chernoff distance for (left or right) truncated random variables and study its various properties. Some useful bounds as well as characterization results are obtained.     

A maximum likelihood estimator for left-truncated lifetimes based on probabilistic prior information about time of occurrence

In forestry, many processes of interest are binary and they can be modeled using lifetime analysis. However, available data are often incomplete, being interval- and right-censored as well as left-truncated, which may lead to biased parameter estimates. While censoring can be easily considered in lifetime analysis, left truncation is more complicated when individual age at selection is unknown. In this study, we designed and tested a maximum likelihood estimator that deals with left truncation by taking advantage of prior knowledge about the time when the individuals enter the experiment. Whenever a model is available for predicting the time of selection, the distribution of the delayed entries can be obtained using Bayes' theorem. It is then possible to marginalize the likelihood function over the distribution of the delayed entries in the experiment to assess the joint distribution of time of selection and time to event. This estimator was tested with continuous and discrete Gompertz-distributed lifetimes. It was then compared with two other estimators: a standard one in which left truncation was not considered and a second estimator that implemented an analytical correction. Our new estimator yielded unbiased parameter estimates with empirical coverage of confidence intervals close to their nominal value. The standard estimator leaded to an overestimation of the long-term probability of survival.     

Bivariate extension of generalized cumulative past entropy

The cumulative past entropy (CPE) of order α, a dual measure of cumulative residual entropy (CRE) of order α, has recently been proposed as a suitable extension of CPE. In this article, we extend the definition of (dynamic) CPE of order α (DCPE(α)) to bivariate setup and obtain some of its properties including bounds. We also look into the problem of extending DCPE(α) for conditionally specified models. Several properties, including monotonicity, and bounds of DCPE(α) are obtained for conditional distributions. Along with some characterization results it is shown that the proposed generalized measure uniquely determines the distribution function. Moreover, we also propose a stochastic order based on this measure and prove interrelation with some existing stochastic orders.     

关于非英语专业学生英语写作教学的几点思考

本文主要探讨了非英语专业学生在英语写作方面的现状、存在问题及其原因，以及为提高学生写作能力所采取的几项措施。     

运动训练专业可持续发展研究

在可持续发展的全球战略中,体育作为人类社会文化的一个重要领域也发生着相应的发展与变革,如何有效地实现体育事业的良性发展,值得每个体育工作者认真思考.作为支柱专业的运动训练,必须确立运动训练专业"为奥运增光和全民健身战略服务的宗旨,培养各类高素质体育专门人才"的可持续发展指导思想,用可持续发展的办学理念迎来运动训练专业的新发展.     

严师风骨 良师风范 大师风采——忆著名水稻学家杨守仁教授

杨守仁教授（1912~2005）,江苏丹阳人,著名水稻学家和农业教育家,在水稻籼粳交育种理论、水稻理想株形研究,水稻超高产育种等领域取得重大科技突破,获国家科技进步二等奖和重点科技攻关奖,1998年获何梁何利基金科学与技术进步奖。杨守仁教授在沈阳农业大学素有严师风骨、良师风范和大师风采,他在水稻科学研究方面许多重要的科学发现大部分在《沈阳农业大学学报》公布,他对科研论文字词句章、段落结构和内容表述要求极为严谨、慎密和准确,体现了稻界泰斗事必求是、理必求真和辩证出新的科学精神。甚至在耄耋之年仍虚心学习,诲人不倦,辛勤耕耘,科教育人,较早地建立了国家超级稻育种科技创新团队,并指导团队在水稻研究方面取得了突破性进展。特别是杨守仁教授在科学研究、人才培养和科研团队建设方面显示出来的管理智慧,值得后来者研究、思考和学习。