On pooling data summaries in the absence of interactions “response-by-study”

The standard hypothesis testing procedure in meta-analysis (or multi-center clinical trials) in the absence of treatment-by-center interaction relies on approximating the null distribution of the standard test statistic by a standard normal distribution. For relatively small sample sizes, the standard procedure has been shown by various authors to have poor control of the type I error probability, leading to too many liberal decisions. In this article, two test procedures are proposed, which rely on thet—distribution as the reference distribution. A simulation study indicates that the proposed procedures attain significance levels closer to the nominal level compared with the standard procedure.     

对我国即将推出"股指期货"的思考

中国加入WTO后，中国的金融业正面临着巨大的挑战。金 融市场的国际化趋势给中国的证券市场提出了更高的要求，单一的投资工具已远远不能满足 投资者的需要。为了更好地与国际接轨，参与国际竞争，中国引入创新的金融衍生工具势在 必行。本文就开发中国股指期货的必要性及由此可能产生的问题提出见解。     

On Block Updating in Markov Random Field Models for Disease Mapping

Gaussian Markov random field (GMRF) models are commonly used to model spatial correlation in disease mapping applications. For Bayesian inference by MCMC, so far mainly single-site updating algorithms have been considered. However, convergence and mixing properties of such algorithms can be extremely poor due to strong dependencies of parameters in the posterior distribution. In this paper, we propose various block sampling algorithms in order to improve the MCMC performance. The methodology is rather general, allows for non-standard full conditionals, and can be applied in a modular fashion in a large number of different scenarios. For illustration we consider three different applications: two formulations for spatial modelling of a single disease (with and without additional unstructured parameters respectively), and one formulation for the joint analysis of two diseases. The results indicate that the largest benefits are obtained if parameters and the corresponding hyperparameter are updated jointly in one large block. Implementation of such block algorithms is relatively easy using methods for fast sampling of Gaussian Markov random fields ( Rue, 2001 ). By comparison, Monte Carlo estimates based on single-site updating can be rather misleading, even for very long runs. Our results may have wider relevance for efficient MCMC simulation in hierarchical models with Markov random field components.     

Conditions for Non-confounding and Collapsibility without Knowledge of Completely Constructed Causal Diagrams

In this paper, we discuss several concepts in causal inference in terms of causal diagrams proposed by Pearl (1993 , 1995a , b ), and we give conditions for non-confounding, homogeneity and collapsibility for causal effects without knowledge of a completely constructed causal diagram. We first introduce the concepts of non-confounding, conditional non-confounding, uniform non-confounding, homogeneity, collapsibility and strong collapsibility for causal effects, then we present necessary and sufficient conditions for uniform non-confounding, homegeneity and collapsibilities, and finally we show sufficient conditions for non-confounding, conditional non-confounding and uniform non-confounding.     

多元化计量模式的现实思考--历史成本与公允价值择优并存

多元化计量模式的现实思考——历史成本与公允价值择优并存@谢桂芬$宁波高等专科学校经管系!浙江宁波315010~~     

血管的三维重建

构建了血管的三维重建模型 ,并给出了模型的算法及其求解结果 .     

存在品牌转移者和品牌忠诚者的产品差异模型

分析了存在品牌转移者和忠诚者两类特殊消费群情况下的两阶段水平差异模型，其中品牌转移者在选择产品时只考虑价格因素而不考虑运输成本，品牌忠诚者总是选择某一品牌的产品而不管价格和运输成本。讨论了在两阶段选址－定价博弈模型中纯战略均衡存在的条件。     

并行编程模式及分析

讨论了主从模型、单控制流多数据流、分治策略、数据流水线、投机策略、混合模型六种并行编程模型的结构和工作方式、性能及特点,分析统计了大量应用程序。指出了并行程序设计中,并行编程模式的选择直接影响了并行程序的正确性和效率,而主从模型和单控制流多数据流在整体性能上最优,程序执行效率也最好,是两种最常用的并行编程模型。     

企业知识创新的整合模式

企业知识创新的模式问题一直是知识管理理论中探讨的热点。本文从知识管理理论视角阐述了知识的概念和结构 ,分析了企业知识管理的涵义与战略 ,并在评述现有的企业知识创新模式的基础上 ,提出自己的企业知识创新的整合模式     

商业银行贷款定价模型构造研究

本文从贷款定价的原则和因素分析着手 ,提出贷款价格由核心价格、风险附加价格和可折让价格三部分组成 ,并建立了贷款定价数学模型。同时 ,利用决策树实现了贷款定价决策。