Estimation of the marginal expected shortfall under asymptotic independence

We study the asymptotic behavior of the marginal expected shortfall when the two random variables are asymptotic independent but positively associated, which is modeled by the so-called tail dependent coefficient. We construct an estimator of the marginal expected shortfall, which is shown to be asymptotically normal. The finite sample performance of the estimator is investigated in a small simulation study. The method is also applied to estimate the expected amount of rainfall at a weather station given that there is a once every 100 years rainfall at another weather station nearby.     

冷战后的中美政治安全关系

冷战结束十年以来 ,美国的对华政策依然摇摆不定。之所以如此 ,是因为十年来美国视中国为敌还是为友 ,或者非敌非友 ,至今还未定性。而美国难于在其国际政治安全战略中给中国定性的原因 ,则与以下的三个层次密切相关 ,即美国的国内政治层次、中美关系的发展层次和全球层次。     

On a Dualization of Graphical Gaussian Models: A Correction Note

Abstract.  We correct two proofs concerning Markov properties for graphs representing marginal independence relations.     

谈激发大学生政治理论课的学习兴趣

政治理论课是大学生必修的一门课程,它不仅向学生讲授马克思主义的理论知识,还要帮助学生树立科学的世界观、人生观和价值观。政治理论课的教学质量如何,不仅影响到每个学生的未来,而且关系到国家的前途。所以我们要大力改进课堂教学,用教学的高质量来培养学生的高素质。如今大学生普遍不喜欢上政治理论课,极大地影响该课程的教学效果,更难以实现政治理论课的智育和德育双重功能。我们认为,针对目前大学政治理论课的低效性现状,可以通过激发学生的学习兴趣来提高政治理论课的教学效果。     

两个随机变量的独立性和相关性之比较

从随机变量的独立性和相关性概念出发,运用反例和定理的形式详细探讨二者的区别和联系.     

Weakly implementable social choice rules

Previous investigations have shown that a social choice function which is partially implementable must be characterized by pervasive veto power. This paper investigates how much additional latitude in the design of social choice functions, and how much relief from this vetoers result, can be achieved by examining multi-valued social choice rules and relaxing the requirement of partial implementability to a requirement that we call weak partial implementability. We find that the power structures which characterize partially implementable social choice functions, including the veto properties, also characterize weakly partially implementable social choice rules. The conclusion is that invoking multi-valuedness and implementation of appealing social choice rules in strong Nash equilibria. Our results apparently exhaust the possibilities for implementation in strong Nash equilibrium. If any implementation possibility results are to be achieved, they can apparently come only by weakening the equilibrium requirement.     

国家权力与城市空间:当代中国城市基层社会治理变革

确立和调整城市治理的空间策略是现代国家的重要任务。改革前中国的单位体制,使国家能够依靠单位实现“单元分隔”式的治理模式。改革以来,这种整齐划一的空间战略无法适应新的城市社会变迁。在城市社区管理体制改革中,出现了三种不同的国家空间战略,即“政党国家”,“行政国家”和“社会化国家”模式。当前城市社区改革的困难和复杂性体现了以上三种空间战略的对立和冲突。     

Social identities and political cleavages: the role of political context

Summary. Using a novel method, the paper investigates the influence of social group identities on attitudes and on voting in a variety of political contexts. Examining the major regions of Britain, Canada and the USA, we find considerable national and regional diversity in the nature of social cleavages. For example, social class and race had widely different effects across societies, but within societies their effects on attitudes and on voting were very similar. However, despite that, age and religion had a similar effect on attitudes across societies; the effects on voting varied considerably. The significant within-country differences underline the importance of using region, rather than country, as the unit of analysis. More importantly, these results highlight the role of political context, especially competing cleavages and the structure of party competition, in the establishment of politically relevant social cleavages.