完全检查下预防维修模型建立及案例分析

为了解决维修间隔期确定的难题,建立了维修间隔期和总停机时间之间关系的目标函数,以及时间延迟维修模型.根据故障记录数据和预防维修活动的检查数据,采用最大似然法估计有关缺陷发生率和时间延迟分布等参数.在所建立目标函数和估计参数的基础上,计算出最优的维修间隔期.     

对中国区域经济条件收敛性的实证检验

中国的区域经济是否存在收敛一直是一个争论不休的话题。国内的研究主要偏重于检验中国的区域经济是否存在绝对收敛和俱乐部收敛。本文基于曼昆,罗默和韦尔在1992年提出的分析方法,将人力资本项加入到经典的索洛模型中,通过构造一个面板数据模型,检验结果表明在统计意义上不能拒斥中国区域经济的条件收敛性。     

英汉语篇文化对比分析三例

外语学习者在正确使用目的语语法规则的同时，还必须具备目的语的语用能力。从跨文化交际的角度来讲，习得目的语的语用规范比习得目的语语言形式规范更重要、更困难。本文试图以语篇分析和语用学的理论为依据，对三类语篇实例进行文化对比分析，从而验证“过渡语篇”的语用失误。     

高可用性系统的研究与实现

研究了高可用系统的结构，介绍了一种高可用系统的实现。在分析系统失效因素和高可用系统结构的基础上，对主要的失效部分（软硬件）进行冗余以提高服务器、磁盘、网络可靠性，据此采用有效的失效探测与恢复机制，实现了一个能够保证整机容错，无单点失效的高可靠系统。     

论“九八”抗洪精神的鲜明时代特征

“九八”抗洪精神具有鲜明的时代特征。它以共产主义精神为灵魂，以大局意识为核心，以社会主义大协作精神为纽带，以革命英雄主义精神为旗帜，以科技、法制和效率意识为动力。这种精神植根于社会主义和改革开放的新时代又推动其发展。     

数据仓库技术与应用

数据仓库是９０年代初提出的概念，是一个作为决策支持系统和联机分析（ＯＬＡＰ）的结构化数据环境，数据仓库对传统数据库的数据进行清理、抽取和转换，并按决策主题的需要进行重新组织，它在发达国家的金融、电讯、证券、保险、零售业也广泛应用，随着我国经济体制的变化、在我国有广泛的应用前景。     

城市社会的时间地理学研究

时间地理学是结合地理学与社会学的研究方法则一种从各种时空制约条件下人的行为研究入手，以全新的视角来解释人地关系的方法，作者在概括地介绍时间地理学的产生背景及方法特色的基础上，重点说明了城市社会研究中时间地理学方法的应用状况，并展望了未来的研究方向。     

Adaptive interval estimation in one-way random effects models

Two-stage procedures are introduced to control the width and coverage (validity) of confidence intervals for the estimation of the mean, the between groups variance component and certain ratios of the variance components in one-way random effects models. The procedures use the pilot sample data to estimate an “optimal” group size and then proceed to determine the number of groups by a stopping rule. Such sampling plans give rise to unbalanced data, which are consequently analyzed by the harmonic mean method. Several asymptotic results concerning the proposed procedures are given along with simulation results to assess their performance in moderate sample size situations. The proposed procedures were found to effectively control the width and probability of coverage of the resulting confidence intervals in all cases and were also found to be robust in the presence of missing observations. From a practical point of view, the procedures are illustrated using a real data set and it is shown that the resulting unbalanced designs tend to require smaller sample sizes than is needed in a corresponding balanced design where the group size is arbitrarily pre-specified.     

Structural Nested Models and Standard Software: A Mathematical Foundation through Partial Likelihood

Abstract.  In observational studies treatment may be adapted to the patient's state during the course of time. These covariates may in turn also react on the treatment under study, and so on. This makes it hard to distinguish between treatment effect and selection bias. Structural nested models aim at estimating treatment effect in such complicated situations, even when treatment may change at any time. We show that structural nested models can often be calculated with standard software, by using standard models to predict treatment as a tool to estimate treatment effect. Robins ( Survival analysis, Volume 6 of Encyclopedia of Biostatistics , John Wiley and Sons, Chichester, 1998) conjectured this, but so far it was unproven. We use a partial likelihood approach to choose the estimators and tests as a subclass of the estimators and tests in Lok (math. ST/0410271 at http://arXiv.org , 2004). We show that this is the class of estimators and tests that can be calculated with standard software. The estimators are consistent and asymptotically normal, and have interesting asymptotic properties.     

Estimation of the Force of Infection from Current Status Data Using Generalized Linear Mixed Models

Based on sero-prevalence data of rubella, mumps in the UK and varicella in Belgium, we show how the force of infection, the age-specific rate at which susceptible individuals contract infection, can be estimated using generalized linear mixed models (McCulloch & Searle, 2001). Modelling the dependency of the force of infection on age by penalized splines, which involve fixed and random effects, allows us to use generalized linear mixed models techniques to estimate both the cumulative probability of being infected before a given age and the force of infection. Moreover, these models permit an automatic selection of the smoothing parameter. The smoothness of the estimated force of infection can be influenced by the number of knots and the degree of the penalized spline used. To determine these, a different number of knots and different degrees are used and the results are compared to establish this sensitivity. Simulations with a different number of knots and polynomial spline bases of different degrees suggest - for estimating the force of infection from serological data - the use of a quadratic penalized spline based on about 10 knots.