Nonparametric Tests for Stratum Effects in the Cox Model

Thispaper considers the stratified proportional hazards model witha focus on the assessment of stratum effects. The assessmentof such effects is often of interest, for example, in clinicaltrials. In this case, two relevant tests are the test of stratuminteraction with covariates and the test of stratum interactionwith baseline hazard functions. For the test of stratum interactionwith covariates, one can use the partial likelihood method (Kalbfleischand Prentice, 1980; Lin, 1994). For the test of stratum interactionwith baseline hazard functions, however, there seems to be noformal test available. We consider this problem and propose aclass of nonparametric tests. The asymptotic distributions ofthe tests are derived using the martingale theory. The proposedtests can also be used for survival comparisons which need tobe adjusted for covariate effects. The method is illustratedwith data from a lung cancer clinical trial.     

当代中国美育观念演变历程考察

从建国以来到 2 0世纪末中国政府有关教育的政策、法规和文件中可以看出 :当代中国美育观念的演变历程是进步、后退 ,此起彼伏 ;到 90年代末 ,国家教育部相继出台的政策、法规再次把美育观念历程推向历史的制高点 ,正式把美育写进教育方针。通过当代中国美育观念的变化轨迹 ,找到症结 ,为 2 1世纪中国美育的理论和实践奠定思想基础。     

卢作孚教育思想及其实践活动述论

近代实业家卢作孚同时也是一位著名的教育家。在 192 5年筹建民生公司以前 ,他是典型而真诚的教育救国论者 ,致力于实业建设后仍以教育为实业的核心。卢作孚的教育活动多姿多彩 ,涉及了民众教育、学校教育、企业教育、社会教育、职业教育等诸多领域 ,期间恰是中国教育转折、反思并通过争鸣和实验而走向中国化探索的关键时期。在我国近现代教育史上 ,卢作孚作为教育家应占有重要地位。     

试析辛提卡的语言博弈论

辛提卡提出语言博弈理论旨在建立一种能用于系统分析或摹拟人的认识活动的过程及其结果的理论。这一理论以可能世界理论为基础 ,它把形式逻辑的模型集合建构看做一种特殊的博弈活动 ,用“寻找且找到博弈”描述以现实为对象的语言活动 ,并刻画了两种博弈之间的联系。“寻找且找到博弈”不同于运算 ,它的结局不是预先可断定的 ;而这一博弈规则是制约着语句F的整个证实过程的规则。     

教育本体论的嬗变与素质 教育本体论命题的创化

本文在教育本体论层面上考辩了教育思想史上关于教育起源的生命本能说、心理模仿说、劳动说、社会交往说等教育原生态的论争,论证了素质教育本体论关于“人体潜能素质的发现、破译和开发”命题假说革新现代教育理论的创化功能     

Social mobility and personal satisfaction: evidence from ten countries

This paper examines survey data relating class mobility to satisfaction and dissatisfaction with seven different domains of everyday life among nationally representative samples of men and women living in ten industrialized nations. The evidence is set against competing pessimistic and optimistic accounts of the mobility experience found in earlier literature. Results show that individuals who move from working-class origins to middle-class destinations are no more likely to be systematically satisfied or dissatisfied with life than are the socially immobile or even those downwardly mobile from advantaged backgrounds into the working class. Indeed, in all nations, the overall association between class experience and satisfaction with life is both weak and uneven across the different life-domains. The study also serves to illustrate an important principle of research methodology more generally.     

Mixed Levels of Uncertainty in Complex Policy Models

The characterization and treatment of uncertainty poses special challenges when modeling indeterminate or complex coupled systems such as those involved in the interactions between human activity, climate and the ecosystem. Uncertainty about model structure may become as, or more important than, uncertainty about parameter values. When uncertainty grows so large that prediction or optimization no longer makes sense, it may still be possible to use the model as a behavioral test bed to examine the relative robustness of alternative observational and behavioral strategies. When models must be run into portions of their phase space that are not well understood, different submodels may become unreliable at different rates. A common example involves running a time stepped model far into the future. Several strategies can be used to deal with such situations. The probability of model failure can be reported as a function of time. Possible alternative surprises can be assigned probabilities, modeled separately, and combined. Finally, through the use of subjective judgments, one may be able to combine, and over time shift between models, moving from more detailed to progressively simpler order-of-magnitude models, and perhaps ultimately, on to simple bounding analysis.     

布莱克─肖尔斯期权定价模型在公司价值评估中的应用

公司股票、债券在本质上可看成是基于公司资产的期权,因而可用期权定价方法对其价值进行评估。本文介绍了最典型的期权定价模型─布莱克一肖尔斯期权定价模型,分析了该模型在公司证券价值评估中的应用。     

魏晋南北朝文学表现家族观念的情感模式

魏晋南北朝时作家多出于世家大族 ,这些作家在他们的作品中表现了强烈的家族观念。家族观念是魏晋南北朝诗文作品表现的一种常见主题 ,但这一主题所呈现出来的情感色彩却有着明显的区别。纵观魏晋南北朝文学创作 ,我们可以将家族观念所表现的情感概括为几种模式 ,一是寄托式 ,二是追忆式 ,三是幻灭式     

“人类灵魂工程师”的教育价值观反思

人们常把教师喻为人类灵魂的工程师。这种理念把教育看作一项工程 ,把学生当作可以改造和加工的“毛坯” ,把教学作为执行建筑蓝图的过程 ,则具有工业时代教育自身无法克服的缺陷 ,值得当今教育工作者反思