RELIABILITY PROPERTIES OF SERIES AND PARALLEL SYSTEMS FROM BIVARIATE EXPONENTIAL MODELS

ABSTRACT

In this paper we study the classification of the generalized mixtures of two or three exponential distributions, in the ILR and DLR classes, and consequently in the IFR and DFR classes. We apply these results to classify the aging of the series and parallel systems, in accord with some common bivariate exponential models of their components.     

有限宽裂纹板受一对集中剪力时弹塑性解

针对运用断裂力学传统方法进行裂纹尖端的弹塑性应力场分析均为小范围塑性区的假定，不能准确反映塑性区应力情况的问题，利用裂纹线场分析方法，对理想弹塑性材料的有限宽平面板在裂纹面受到一对集中剪力作用时裂纹线附近的应力场及弹塑性边界进行了分析。不采用小范围塑性区的假设，直接通过将裂纹线附近弹塑性边界上弹性应力场与塑性应力场的匹配，获得了裂纹线附近弹塑性应力场的解析解以及弹塑性边界上单位法向量的表达式。用裂纹线分析方法可以准确地反映裂纹附近的弹塑性应力分布，该种方法的应用将成为断裂力学的一个重要发展方向，对石油天然气构造应力分析、材料力学分析具有参考价值。     

Heterogeneity in Parent‐reported Social Skill Development in Early Elementary School Children

Despite known risks associated with aberrant social skill development, there has been a relative dearth of literature on typical developmental changes in social skills over time. In this study, we examine systematic changes in social skills from kindergarten (typical age of 5–6 years) to third grade (typical age of 8–9 years), and focus on systematic heterogeneity across these developmental trajectories. Data came from the National Head Start—Public School Early Childhood Transition Demonstration Project (N = 6964). Mixture models provide evidence for multiple classes of individuals representing heterogeneity in the development of social skills. Classes were defined as a majority class (whose trajectories remained relatively stable over time), an increasing class (whose trajectories increased at a faster rate than the majority class), and a decreasing class (whose trajectories decreased at a faster rate than the majority class). Developmental trends accounted for a substantial proportion of the variance in social skill components. Implications and limitations of the study are discussed.     

Estimation on Varying-Coefficient Partially Linear Model With Different Smoothing Variables

The authors give the estimation on the varying-coefficient partially linear regression model with different smoothing variables. The efficient estimators of the intercept function and the coefficient functions are obtained by a one-step back-fitting technique based on their initial estimators given by local linear technique and the averaged method. Furthermore, their asymptotic normalities are given. Some simulation studies are used to illustrate the performances of the estimation.     

Overdispersed negative binomial regression models

Overdispersion is a common phenomenon in actual data sets. It is important to have methods of dealing with extra variation in regression situations. This article develops tests for extra-negative binomial variation and gives some numerical methods to deal with it. Simulations show power comparisons between some of the overdispersion tests discussed. Finally, an example is given to demonstrate the methods.     

李家坝煤矿斜井开拓局部冻结关键技术研究

斜井冻结技术尚处于摸索研究阶段，国内无统一的施工规范。在李家坝煤矿斜井冻结工程实践的基础上开展应用性研究，详细阐述了斜井局部冻结的设计原则、施工关键技术，尤其是快速造孔施工及冻结管保温层施工工艺，提出了冻结管保温接头处理方式，成功应用了斜井冻结步进式投入法，解决了斜井局部冻结关键技术，为类似局部冻结工程提供了借鉴和参考。     

《中国文化史》教学的思考

在新的历史时期,加强和改进人文素质教育,对于高等教育的人才培养工作具有重要意义。"中国文化史"作为高校人文素质教育的一门基础课程,针对不同的教育教学环境,在内容的设计上要注意系统性与灵活性相协调,注意深入与浅出相结合。在课堂教学方式方面,要尽可能让学生参与教学活动,引导他们融入课堂、感受文化,同时要探索多样化的教学媒介,在提升学生学习兴趣的前提下,推动其学习能力不断向广度和深度发展。     

虐童的刑法规制及儿童福利体系的构建

基于虐童现象的普遍性以及后果的严重性，虐童行为的规制成为必要，但方式应该是通过立法，而非司法。对于实践中以司法方式实现虐童入罪的做法，应当摒弃，并肃清其背后的理念、逻辑。虐童入罪固然必要，但是问题的解决更应该走向刑法之外，通过儿童保护及福利体系的建立，从根本上减少虐童现象的发生。     

基于科学发展观的人类发展指标体系研究——以苏州市为例

科学发展观是统领我国社会经济发展的重要指导思想。而要将此重要理念付诸实施,贯彻落实到政府部门具体的行政工作中,建立科学的人类发展评价体系和正确的政府工作引导机制至关重要。本课题试图以苏州为例,以科学发展观为指导,通过对现有的人类发展指数及其相关指标的应用评估,提出新的基于科学发展的人类发展指标体系,并运用实际资料通过横向和纵向比较来评估新世纪以来苏州在人类发展中所取得的进展以及新的人类发展指标体系的应用状况。     

Accent on Teaching Materials

A linear combination test for combining several tests of the correlation coefficient in the bivariate normal distribution is proposed. The linear combination test is compared with the well-known Fisher method of combining tests. It is shown by a Monte Carlo study that the linear combination test has a larger power.