Divergence-based estimation and testing with misclassified data

The well-known chi-squared goodness-of-fit test for a multinomial distribution is generally biased when the observations are subject to misclassification. In Pardo and Zografos (2000) the problem was considered using a double sampling scheme and ø-divergence test statistics. A new problem appears if the null hypothesis is not simple because it is necessary to give estimators for the unknown parameters. In this paper the minimum ø-divergence estimators are considered and some of their properties are established. The proposed ø-divergence test statistics are obtained by calculating ø-divergences between probability density functions and by replacing parameters by their minimum ø-divergence estimators in the derived expressions. Asymptotic distributions of the new test statistics are also obtained. The testing procedure is illustrated with an example.     

Assessing accuracy of a continuous screening test in the presence of verification bias

Summary.  In studies to assess the accuracy of a screening test, often definitive disease assessment is too invasive or expensive to be ascertained on all the study subjects. Although it may be more ethical or cost effective to ascertain the true disease status with a higher rate in study subjects where the screening test or additional information is suggestive of disease, estimates of accuracy can be biased in a study with such a design. This bias is known as verification bias. Verification bias correction methods that accommodate screening tests with binary or ordinal responses have been developed; however, no verification bias correction methods exist for tests with continuous results. We propose and compare imputation and reweighting bias-corrected estimators of true and false positive rates, receiver operating characteristic curves and area under the receiver operating characteristic curve for continuous tests. Distribution theory and simulation studies are used to compare the proposed estimators with respect to bias, relative efficiency and robustness to model misspecification. The bias correction estimators proposed are applied to data from a study of screening tests for neonatal hearing loss.     

Influence diagnostics and outlier tests for semiparametric mixed models

Summary. Semiparametric mixed models are useful in biometric and econometric applications, especially for longitudinal data. Maximum penalized likelihood estimators (MPLEs) have been shown to work well by Zhang and co-workers for both linear coefficients and nonparametric functions. This paper considers the role of influence diagnostics in the MPLE by extending the case deletion and subject deletion analysis of linear models to accommodate the inclusion of a nonparametric component. We focus on influence measures for the fixed effects and provide formulae that are analogous to those for simpler models and readily computable with the MPLE algorithm. We also establish an equivalence between the case or subject deletion model and a mean shift outlier model from which we derive tests for outliers. The influence diagnostics proposed are illustrated through a longitudinal hormone study on progesterone and a simulated example.     

对网络教学的分析和探讨

随着知识经济的发展 ,网络已经日渐走入人们的生活并且开始显示其重要性。同时 ,社会对教育模式、教育手段都提出了新的要求。网络教学作为一种新型的教育方式 ,在我国迅速发展起来 ,并且成为远程教育的重要形式之一。本文就网络教学的学习理论、特点、定位以及现阶段我国网络教学与发达国家网络教学的差距进行了分析和探讨 ,并对我国网络教学今后的发展方向和需要解决的问题 ,提出了个人的见解。     

Internet与未来教育

Internet是20世纪末世界上最激动人心的发现,它将我们带入了一个完全信息化的时代,它正在改变着人们的生活和工作方式,也必将对中国未来教育发生深远的影响。从教育的内容、教育的方式方法、教育的观念等诸方面阐述了Internet对未来教育的影响,分析了未来教育将向着终身化、远程化和多媒体化、大众化、个性化、产业化和市场化等方向发展的趋势,同时提出了我们应采取的对策。     

贫困地区低保动态管理探析

本文从贫困人口需求获得经济利益与主体管理部门动态性控制二者的矛盾入手,对贫困地区低保动态管理的内涵进行了探析,并将低保动态管理分为三个类型:一是对象平行动态,二是实行标准上下动态,三是需求类型变化动态,进而提出了解决低保动态管理问题的路径及措施.     

深化多媒体教学推进远程教育的发展

本文通过对国内外现代远程教育的探讨,对多媒体教学的分析,提出了我国高等教育要赶超世界先进水平、发展远程教育目前所面临的主要问题及对策.     

师生人际距离新论

人际距离是影响人际关系的一个重要因素,贯穿于整个教育过程中的师生距离是人际关系的重要内容,是影响师生交往,进而影响教育教学效果的一个关键因素.师生距离到底该近还是该远,一直是教育理论界热衷的话题.本文结合多年实践中的教育实例,就师生距离的远近问题作一新探讨与解读.     

一类非线性混合整规划的无约束连续化解法

将整系数多项式 0 - 1混合整规划问题化成无约束多项式规划问题。通过解该问题 ,能得到原问题的近似解。处理方法的特点是能够直接处理不等式约束情形 ,而不需要先将不等式约束化成等式约束再来处理