Multivariate Life Testing in Variably Scaled Environments

This paper examines modeling and inference questions for experiments in which different subsets of a set of k possibly dependent components are tested in r different environments. In each environment, the failure times of the set of components on test is assumed to be governed by a particular type of multivariate exponential (MVE) distribution. For any given component tested in several environments, it is assumed that its marginal failure rate varies from one environment to another via a change of scale between the environments, resulting in a joint MVE model which links in a natural way the applicable MVE distributions describing component behavior in each fixed environment. This study thus extends the work of Proschan and Sullo (1976) to multiple environments and the work of Kvam and Samaniego (1993) to dependent data. The problem of estimating model parameters via the method of maximum likelihood is examined in detail. First, necessary and sufficient conditions for the identifiability of model parameters are established. We then treat the derivation of the MLE via a numerically-augmented application of the EM algorithm. The feasibility of the estimation method is demonstrated in an example in which the likelihood ratio test of the hypothesis of equal component failure rates within any given environment is carried out.     

低渗气藏多次应力敏感测试及应用

低渗透气田在我国已开发气藏中占有相当大比例，应力敏感性对气田开发的影响已逐渐引起人们重视。针对目前大多数低渗透气田应力敏感测试仍然采用定内压变围压测试方式所存在的与实际气田开发过程中内压变化上覆压力恒定的变化规律不一致的问题，研究提出了变内压定围压测试方法，采用该方式测试低渗透岩芯在净上覆压力六升六降过程中应力敏感性,并应用测试的应力敏感曲线对低渗透气井试井特征及单井生产动态进行研究。结果表明：变内压定围压测试方法更接近于气田实际压力变化过程；（不）考虑应力敏感试井分析两者在试井特征曲线第II阶段相差较大，五开五关试井分析表明渗透率应力敏感效应的存在对气藏的开发是不利的；应力敏感对单井模拟井底流压影响很大，考虑应力敏感时，气井生产压差明显增大。因此，在低渗透气田开发过程中，必须注意应力敏感对气田开发的影响。     

经济增长由投资拉动转向消费拉动的现实选择——基于税收政策效应的实证分析

消费是影响和决定国民收入的重要因素，如何实现经济增长由投资拉动向消费拉动的转变，是当前经济形势下迫切需要解决的问题。通过引入虚拟变量，从税收政策视角建立消费函数计量模型，对影响中国居民消费行为的因素进行了量化和深入分析，并基于模型的分析结果给出了政策界面。     

英语口语训练课外“源环境”塑造的几种途径

当前，高校学生英语口语能力总体薄弱，而口语“源环境”的匮乏又使口语训练变得困难，文章主要探讨在这一现实状况下，高校英语教师如何利用现有的资源，帮助学生打造口语训练的课外“源环境”；如何让学生通过“英语寝室”。“自言自语”等容易组织、容易上手的平台，自觉形成说英语的习惯，并持续以良好的能动的状态，由浅人深地进行英语口语的自我训练。     

Nonparametric tests of hypotheses for umbrella alternatives

The author proposes a general method for constructing nonparametric tests of hypotheses for umbrella alternatives. Such alternatives are relevant when the treatment effect changes in direction after reaching a peak. The author's class of tests is based on the ranks of the observations. His general approach consists of defining two sets of rankings: the first is induced by the alternative and the other by the data itself. His test statistic measures the distance between the two sets. The author determines the asymptotic distribution for some special cases of distances under both the null and the alternative hypothesis when the location of the peak is known or unknown. He shows the good power of his tests through a limited simulation study     

中美高校知识产业化影响因素的比较和启示

对中美大学知识产业化的现状和知识产业化的法律环境、技术转让机构和从业人员、技术信息服务等方面的因素进行了比较,并提出我国高校科研成果转化中应注意的几点启示。     

基于网络环境下馆员服务观念要深化和拓展

从高校图书馆的信息优势和资源优势出发,对文献资源的开发利用和共享问题进行了探讨。     

我国国债回购利率基本特征与统计检验

通过对我国国债回购市场利率的基本特征进行分析,指出了我国国债回购利率的统计特征,为人们对利率模型进行进一步的分析,给出一些基础性结论。     

商业银行利率风险管理技术综述

一、引言(一)现实背景从2000年9月21日起,我国利率市场化改革进入实质性阶段,预计三年内完成。利率市场化是一场系统性的金融革命,必将对经济金融领域的方方面面产生重要影响。商业银行应积极采取措施,应对利率市场化将带来的一系列风险。近几年,我国发行了大量的国债和金融债,     

计算机网络实验教学研究

针对计算机网络实验条件差这一状况,作者结合实际情况,编写了实验教材和网络实验环境的建设方案,并在以下几个方面提高学生的专业能力:分析软、硬件产品的能力;维修软、硬件产品的能力;设计软、硬件和试验开发的能力;学习、掌握和应用现有设备的能力,特别是组织构造系统应用环境的集成能力。为此,计算机网络实验教材应将计算机网络的理论基础与实验教学内容有机地组织起来,以适应社会发展的需要。