Fitting competing risks data to bivariate Pareto models

This paper revisits two bivariate Pareto models for fitting competing risks data. The first model is the Frank copula model, and the second one is a bivariate Pareto model introduced by Sankaran and Nair (1993 Sankaran, P. G., and N. U. Nair. 1993. A bivariate Pareto model and its applications to reliability. Naval Research Logistics 40 (7):1013–1020. doi:10.1002/1520-6750(199312)40:7%3c1013::AID-NAV3220400711%3e3.0.CO;2-7.[Crossref], [Web of Science ®] , [Google Scholar]). We discuss the identifiability issues of these models and develop the maximum likelihood estimation procedures including their computational algorithms and model-diagnostic procedures. Simulations are conducted to examine the performance of the maximum likelihood estimation. Real data are analyzed for illustration.     

论新媒体冲击下纸媒的生存与发展——以报纸为例

互联网的发展、智能手机的普及使传统的传媒环境和格局发生了翻天覆地的变化。新媒体的崛起与壮大给以纸媒为代表的传统媒体带来了前所未有的冲击，但不可否认的是，纸媒自身依然有不可替代的优势。本文主要以报纸为例，从纸媒传播内容的深度和可信度、纸媒对于受众文化素质的要求以及纸媒的表现形式、和受众的互动等方面的特点入手，分析在新媒体的冲击下纸媒所面临的生存现状，并且在此基础上指出将来纸媒应该如何利用新媒体的技术来促进自身的发展，更好地实现新媒体与传统媒体的融合。     

A goodness of fit test for multilevel survival data

No satisfactory goodness of fit test is available for multilevel survival data which occur when survival data are clustered or hierarchical in nature. Hence the aim of this research is to develop a new goodness of fit test for multilevel survival data and to examine the properties of the newly developed test. Simulation studies were carried out to evaluate the type ? error and the power. The results showed that the type I error holds for every combination tested and that the test is powerful against the alternative hypothesis of nonproportional hazards for all combinations tested.     

能源安全体系建构的理论与实践

在我国能源安全面临的一系列重大问题中，能源领域的政策规划薄弱，法律保障制度建设与管理体制改革滞后，能源供应与能源安全保障体系缺乏相关政策、法律和制度的保障。只有真正做到政策、法律和管理体制“三位一体”，才能确保国家能源安全。本文从能源安全体系建构的理论和实践出发，借鉴西方能源安全战略实践，从政策、法律和管理体制等角度，对我国能源安全体系的内在机制建构进行分析，旨在为我国与中东能源合作提供借鉴与参考。     

综述和讨论:关于小民族的生存及前景

作为人类社会、人类文化重要组成部分的小民族的生存及未来前景问题,他们因传统文化特点、因外部社会因素而引发的带有小民族特有特点的现实生存难题,早已引起人类学以及相关学科的高度重视,我国近些年对国内小民族的研究也渐成气象。那么,国内就小民族生存、发展问题的关注和实证研究状况如何?近数十年来,整个学界围绕小民族生存和未来前景以及影响因素的探讨,主要关注了哪些层面?提出了哪些主要观点?从问题意识出发,并结合自己有限的田野工作经验,本文尝试进行初步的综述和讨论。     

Semiparametric Estimation of a Change-point for Recurrent Events Data

One particular recurrent events data scenario involves patients experiencing events according to a common intensity rate, and then a treatment may be applied. The treatment might be effective for a limited amount of time, so that the intensity rate would be expected to change abruptly when the effect of the treatment wears out. In particular, we allow models for the intensity rate, post-treatment, to be at first decreasing and then change to increasing (and vice versa). Two estimators of the location of this change are proposed.     

试析中国与沙特阿拉伯的石油合作

沙特阿拉伯是世界第一大原油生产国和出口国,中国是世界第二大石油消费国和消费量增长最快的石油进口国.沙特需要为其巨大的能源储量寻找新的市场,中国需要海外能源满足经济增长的需要.因此,两国在能源领域存在着相互依赖关系.正是这种相互依赖关系推动着中沙关系的稳步发展,本文力图运用政治经济学的分析法对中沙石油合作做出理性分析与判断.     

Factors influencing Soay sheep survival

We present a survival analysis of Soay sheep mark recapture and recovery data. Unlike previous conditional analyses, it is not necessary to assume equality of recovery and recapture probabilities; instead these are estimated by maximum likelihood. Male and female sheep are treated separately, with the higher numbers and survival probabilities of the females resulting in a more complex model than that used for the males. In both cases, however, age and time aspects need to be included and there is a strong indication of a reduction in survival for sheep aged 7 years or more. Time variation in survival is related to the size of the population and selected weather variables, by using logistic regression. The size of the population significantly affects the survival probabilities of male and female lambs, and of female sheep aged 7 or more years. March rainfall and a measure of the North Atlantic oscillation are found to influence survival significantly for all age groups considered, for both males and females. Either of these weather variables can be used in a model. Several phenotypic and genotypic individual covariates are also fitted. The only covariate which is found to influence survival significantly is the type of horn of first-year female sheep. There is a substantial variation in the recovery probabilities over time, reflecting in part the increased effort when a population crash was expected. The goodness of fit of the model is checked by using graphical procedures.     

Macro-Economic Factors in Credit Risk Calculations: Including Time-Varying Covariates in Mixture Cure Models

The prediction of the time of default in a credit risk setting via survival analysis needs to take a high censoring rate into account. This rate is because default does not occur for the majority of debtors. Mixture cure models allow the part of the loan population that is unsusceptible to default to be modeled, distinct from time of default for the susceptible population. In this article, we extend the mixture cure model to include time-varying covariates. We illustrate the method via simulations and by incorporating macro-economic factors as predictors for an actual bank dataset.     

The politics of gender in the UN Security Council resolutions on women,peace and security

Women’s groups have worked diligently to place gender and women’s vulnerability on the transnational security agenda. This article departs from the idea that negotiating and codifying gender and women’s vulnerability in terms of security represent a challenge to mainstream security contexts. By contrasting the UN Security Council resolutions on women, peace and security with feminist theory, this article aims to analyze what is considered to be threatened when women’s vulnerability is negotiated. The article identifies two approaches to the gender/security nexus: gendering security, which involves introducing ideas regarding gender-sensitive policies and equal representation, and securitizing gender, which proceeds by locating rape and sexual violence in the context of war regulations. We demonstrate that, although these measures are encouraged with reference to women’s vulnerability, they serve to legitimize war and the male soldier and both approaches depoliticize gender relations.