Semiparametric median residual life model and inference

For randomly censored data, the authors propose a general class of semiparametric median residual life models. They incorporate covariates in a generalized linear form while leaving the baseline median residual life function completely unspecified. Despite the non‐identifiability of the survival function for a given median residual life function, a simple and natural procedure is proposed to estimate the regression parameters and the baseline median residual life function. The authors derive the asymptotic properties for the estimators, and demonstrate the numerical performance of the proposed method through simulation studies. The median residual life model can be easily generalized to model other quantiles, and the estimation method can also be applied to the mean residual life model. The Canadian Journal of Statistics 38: 665–679; 2010 © 2010 Statistical Society of Canada     

Smoothed empirical likelihood confidence intervals for the relative distribution with left‐truncated and right‐censored data

The study of differences among groups is an interesting statistical topic in many applied fields. It is very common in this context to have data that are subject to mechanisms of loss of information, such as censoring and truncation. In the setting of a two‐sample problem with data subject to left truncation and right censoring, we develop an empirical likelihood method to do inference for the relative distribution. We obtain a nonparametric generalization of Wilks' theorem and construct nonparametric pointwise confidence intervals for the relative distribution. Finally, we analyse the coverage probability and length of these confidence intervals through a simulation study and illustrate their use with a real data set on gastric cancer. The Canadian Journal of Statistics 38: 453–473; 2010 © 2010 Statistical Society of Canada     

Optimal Composite Markers for Time‐Dependent Receiver Operating Characteristic Curves with Censored Survival Data

Abstract. To increase the predictive abilities of several plasma biomarkers on the coronary artery disease (CAD)‐related vital statuses over time, our research interest mainly focuses on seeking combinations of these biomarkers with the highest time‐dependent receiver operating characteristic curves. An extended generalized linear model (EGLM) with time‐varying coefficients and an unknown bivariate link function is used to characterize the conditional distribution of time to CAD‐related death. Based on censored survival data, two non‐parametric procedures are proposed to estimate the optimal composite markers, linear predictors in the EGLM model. Estimation methods for the classification accuracies of the optimal composite markers are also proposed. In the article we establish theoretical results of the estimators and examine the corresponding finite‐sample properties through a series of simulations with different sample sizes, censoring rates and censoring mechanisms. Our optimization procedures and estimators are further shown to be useful through an application to a prospective cohort study of patients undergoing angiography.     

On Loss Distributions from Installment-Repaid Loans

The banks have been accumulating huge data bases for many years and are increasingly turning to statistics to provide insight into customer behaviour, among other things. Credit risk is an important issue and certain stochastic models have been developed in recent years to describe and predict loan default. Two of the major models currently used in the industry are considered here, and various ways of extending their application to the case where a loan is repaid in installments are explored. The aspect of interest is the probability distribution of the total loss due to repayment default at some time. Thus, the loss distribution is determined by the distribution of times to default, here regarded as a discrete-time survival distribution. In particular, the probabilities of large losses are to be assessed for insurance purposes.     

A Semi-parametric Bayesian Analysis of Survival Data Based on Lévy-driven Processes

In the presence of covariate information, the proportional hazards model is one of the most popular models. In this paper, in a Bayesian nonparametric framework, we use a Markov (Lévy-driven) process to model the baseline hazard rate. Previous Bayesian nonparametric models have been based on neutral to the right processes, which have a number of drawbacks, such as discreteness of the cumulative hazard function. We allow the covariates to be time dependent functions and develop a full posterior analysis via substitution sampling. A detailed illustration is presented.     

Tree-structured subgroup analysis for censored survival data: Validation of computationally inexpensive model selection criteria

The performance of computationally inexpensive model selection criteria in the context of tree-structured subgroup analysis is investigated. It is shown through simulation that no single model selection criterion exhibits a uniformly superior performance over a wide range of scenarios. Therefore, a two-stage approach for model selection is proposed and shown to perform satisfactorily. Applied example of subgroup analysis is presented. Problems associated with tree-structured subgroup analysis are discussed and practical solutions are suggested.     

在碎片中破土——从“震惊”看《发达资本主义时代的抒情诗人》

本雅明《发达资本主义时代的抒情诗人》一书充满了形形色色的人与物,但在纷繁复杂的意象中,震惊一以贯之,成为探寻问题的一个起点和动因。文章从震惊的心理溯源开始来梳理本雅明的美学思想和社会学思想,以期从这一特定角度对本雅明的现代性思想有一个较为明晰的理解。心理层面,人们以牺牲事物的完整性和鲜活性为代价,发展出一套针对震惊的戒备机制。美学领域,震惊剥夺了传统艺术的光晕,而波德莱尔的伟大之处正在于把震惊引入了抒情诗。震惊还引发了新的社会现象,这就是以游荡者为代表的人群,以及以摄影为代表的物象,人的异化不可避免地产生了。     

“秩序审美”的伦理向度——以群体性事件生成机制为解读路径

文章通过透视热点新闻,揭示其背后的始作俑者——"秩序审美"的冲动,以群体性事件生成机制为解读路径,探讨冲突的暴力化、群体化折射出的价值取向,从而引出"秩序审美"的伦理向度问题,以理性、善为载体,反思新闻背后的社会机理,并提出幸福城市的伦理生态构建。     

有根的诗学 ——叶维廉诗学与道家美学

叶维廉先生是公认的中国现代诗学大家,其诗学的根深植于诗歌创作和中华文化,同时又极富理论智慧和世界眼光。叶维廉诗学的特点在于其把诗学建设自觉纳入一种道家文化的话语体系进行诠释,或者也可以说是从一种道家文化的眼光来诠释诗学问题。有根的诗学使叶维廉先生的诗学进一步超越了对于文学规律的寻求,而进入到真正意义上的诗歌美学和诗的哲学的境界。     

身体与治理术--基于近代以来妇女解放运动的考察

身体从来都不是纯粹的物质存在,而是带着福柯所说的被形形色色的权力所规训和干预的烙印。女性的身体由于其柔弱性、可变性及可塑性,成为近代以来民族与国家叙事下妇女解放运动的符号载体。革命时期解放妇女的种种政策,是服务于革命对“文明、进步”符号意义的需求和革命补充后备力量的需要;建设时期“男女各顶半边天”的意识形态,本质上是为了最大程度动员女性劳动力参与迫在眉睫的生产建设;而新时期塑造“新妇女”形象的号召,则是为市场转型扫除障碍,使女性成为父权制和资本谋利的对象。当代社会消费主义盛行,身体的美学化成为流行趋势,女性看似在积极地塑造出符合标准的身体,然而却再一次落入权力的游戏中。