Estimation of parameters and reliability from generalized life models

Simultaneous estimation of parameters with p (≥ 2) components, where each component has a generalized life distribution, is considered under a sum of squared error loss function. Improved estimators are obtained which dominate the maximum likelihood and the niinimum mean square estimators. Robustness of the improved estimators is shown even when the component distributions are dependent. The result is extended to the estimation of the system reliability when the components are connected in series. Several numerical studies are performed to demonstrate the risk improvement and the Pitman closeness of the new estimators.     

Bayes estimators of the average failure rates

In the present paper we have proposed a Bayesian approach for making inferences from accelerated life tests which do not require distributional assumptions     

Models for two-way contingency tables

We derive a theoretical and parametrized form for a two-way contingency table by using matrix calculus and Kronecker products.     

Characterizations of the poisson process using,the variance

Let γ(t) be the residual life at time t of the renewal process {A(t), t > 0}, which has F as the common distribution function of the inter-arrival times. In this article we prove that if Var(γ(t)) is constant, then F will be exponentially or geometrically distributed under the assumption F is continuous or discrete respectively. An application and a related example also are given.     

The limitations of using school league tables to inform school choice

Summary. In England, so-called 'league tables' based on examination results and test scores are published annually, ostensibly to inform parental choice of secondary schools. A crucial limitation of these tables is that the most recent published information is based on the current performance of a cohort of pupils who entered secondary schools several years earlier, whereas for choosing a school it is the future performance of the current cohort that is of interest. We show that there is substantial uncertainty in predicting such future performance and that incorporating this uncertainty leads to a situation where only a handful of schools' future performances can be separated from both the overall mean and from one another with an acceptable degree of precision. This suggests that school league tables, including value-added tables, have very little to offer as guides to school choice.     

Some results on generalized ageing classes

In this paper we provide new results about generalized ageing classes on the excess lifetime of a renewal process. We also obtain some characterizations of generalized ageing classes by means of the residual life at random time.     

Missing item imputation for quality-of-life instruments with application to asthma quality-of-life questionnaires

There has been increasing use of quality-of-life (QoL) instruments in drug development. Missing item values often occur in QoL data. A common approach to solve this problem is to impute the missing values before scoring. Several imputation procedures, such as imputing with the most correlated item and imputing with a row/column model or an item response model, have been proposed. We examine these procedures using data from two clinical trials, in which the original asthma quality-of-life questionnaire (AQLQ) and the miniAQLQ were used. We propose two modifications to existing procedures: truncating the imputed values to eliminate outliers and using the proportional odds model as the item response model for imputation. We also propose a novel imputation method based on a semi-parametric beta regression so that the imputed value is always in the correct range and illustrate how this approach can easily be implemented in commonly used statistical software. To compare these approaches, we deleted 5% of item values in the data according to three different missingness mechanisms, imputed them using these approaches and compared the imputed values with the true values. Our comparison showed that the row/column-model-based imputation with truncation generally performed better, whereas our new approach had better performance under a number scenarios.     

将生命还给社会:传记法作为一种总体叙事方式

在田野民族志和历史编纂学中，传记法是一种重要的叙事方式。本文从分析林耀华的作品入手，将其置于20世纪20年代以来的社会学和人类学思想脉络中，并在此基础上探讨传记法在中国历史和社会研究中的潜力与可能性。本文将谱系法、个人生命史和社会生命论归纳为“传记法三角”。在（扩展）谱系法和社会结构论的基础上，生命传记法可以呈现一个或多个人的生命历史，作为大历史中的片段。不过，现象学路径有其自身的限度，不能离开对中央政权本身和总体结构的考察。在“时势”和“社会结构”的变迁过程中呈现生命传记，才不会只是个体的故事，而有希望成为一种对中国“总体”社会生活的有力叙事方式。     

生命信息的交融互渗——中国花鸟画审美初探

自然界的有生命之物,以其不同的形状、色彩、气息和动静之态,而有着不同的审美价值.它们的美是生命之美.中国花鸟画不以再现自然对象的外形为目的,而以思想、情感、意趣等生命现象的高级形式反映在作品中.作者根据主观的审美理想和自我生命的节律加以重新创造,使其固定为物化状态,给人以美的滋养.     

论孙犁创作的民族化特色

孙犁的文学创作具有鲜明的民族化特色。他的作品呈现了中华民族特有的民族心理、民族精神和民族生活，对中国文学的优秀民族形式加以借鉴、吸收和创新。另外，孙犁创作的民族化特色还表现在他对“五四”传统的继承和发扬上。