关于n维单形宽度的一个结果

证明了关于ｎ维单形宽度的一个不等式，结果是Ｗ≤（ｓｉｎθ）１／２αｎ１ｎ＋１ｎ＋１ｉ＝１Ｒ２ｉ１／２．这一结果蕴含并推广了Ｓａｌｅｅ－Ａｌｅｘａｎｄｅｒ定理     

Estimation for u-shaped beta distributions: minimum hellinger distance and related methods

We compare minimum Hellinger distance and minimum Heiiinger disparity estimates for U-shaped beta distributions. Given suitable density estimates, both methods are known to be asymptotically efficient when the data come from the assumed model family, and robust to small perturbations from the model family. Most implementations use kernel density estimates, which may not be appropriate for U-shaped distributions. We compare fixed binwidth histograms, percentile mesh histograms, and averaged shifted histograms. Minimum disparity estimates are less sensitive to the choice of density estimate than are minimum distance estimates, and the percentile mesh histogram gives the best results for both minimum distance and minimum disparity estimates. Minimum distance estimates are biased and a bias-corrected method is proposed. Minimum disparity estimates and bias-corrected minimum distance estimates are comparable to maximum likelihood estimates when the model holds, and give better results than either method of moments or maximum likelihood when the data are discretized or contaminated, Although our re¬sults are for the beta density, the implementations are easily modified for other U-shaped distributions such as the Dirkhlet or normal generated distribution.     

Bayesian estimation and influence diagnostics of generalized partially linear mixed-effects models for longitudinal data

This paper develops a Bayesian approach to obtain the joint estimates of unknown parameters, nonparametric functions and random effects in generalized partially linear mixed models (GPLMMs), and presents three case deletion influence measures to identify influential observations based on the φ-divergence, Cook's posterior mean distance and Cook's posterior mode distance of parameters. Fisher's iterative scoring algorithm is developed to evaluate the posterior modes of parameters in GPLMMs. The first-order approximation to Cook's posterior mode distance is presented. The computationally feasible formulae for the φ-divergence diagnostic and Cook's posterior mean distance are given. Several simulation studies and an example are presented to illustrate our proposed methodologies.     

Detection of outliers in simple circular regression models using the mean circular error statistic

The investigation on the identification of outliers in linear regression models can be extended to those for circular regression case. In this paper, we propose a new numerical statistic called mean circular error to identify possible outliers in circular regression models by using a row deletion approach. Through intensive simulation studies, the cut-off points of the statistic are obtained and its power of performance investigated. It is found that the performance improves as the concentration parameter of circular residuals becomes larger or the sample size becomes smaller. As an illustration, the statistic is applied to a wind direction data set.     

基于有效预测区域的模糊数据关联

多目标多传感器跟踪系统由数据关联和目标状态估计两部分组成,数据关联是多目标跟踪系统研究的核心。数据关联和目标状态估计两部分既有一定的独立性又有密切的联系,而将两部分合理地结合对提高跟踪系统的性能是重要的。该文以跟踪目标的有效预测区域为依据,利用基于Mahalanobis距离的模糊均值聚类方法解决数据关联问题,在一定程度上将数据关联和目标状态估计两个不同的过程相结合,仿真计算说明了其有效性。     

网络教学与教育技术学学科建设

教育是社会进步的标志,教育技术是教育过程中的重要环节。它包括的内容甚广,从材料、工具到系统和方法。随着科学技术的发展,网络教育代替了旧时代的传统教育,无论从内容和形式上都是受教育者接受教育的最好,最捷径的方式之一,但它也有待管理,在未来的网络教育中将发挥更大作用。     

Psychic distance, psychic distance paradox and behavioral economics: Modeling MNC entry behavior in foreign markets

Assuming that MNCs face a much more complex environment that local enterprizes, the paper begins by discussing what economist Beckerman called psychic distance. After a historical discussion of this concept, I also discuss what O’Gardy and Lane called psychic distance paradox. Then, I argue that these two concepts have a great deal of relevance beyond their original intent of international trade-they are also relevant to FDI and all other formas of international production and exchange. Next, I argue, as I have done in several previous papers, that behavioral economics has a great deal of relevance to FDI and international productive activity; I also argue that behavioral economics can be utilized to describe the concepts of psychic distance and psychic distance paradox. Then, I develop a behavioral economics-based model that can explain the concepts of psychic distance and psychic distance paradox, and their relevance to the modes of entry of MNCs in international markets. In doing so, I argue that FDI and MNC behavior in general need not be explained outside of economics, since, in contrast to neo-classical economics, behavioral economics is capable of capturing the complexities of global markets.     

基于Web的远程网络教学平台设计

文章针对网络教育发展的需要和国内远程网络教学平台的实际情况,对远程网络教学平台的设计思路及总体结构设计进行了研究与探讨,并介绍了远程网络教学平台的功能模块设计与开发设计采用的关键技术。     

网络远程学习中的低绩效现象及解决方案

在网络远程学习中，由于师生时空分离，学生面对大量的信息会出现无所适从、信息迷航现象，从而造成学习的低绩效。这既有来自学习者自身的原因，也有来自于学习资源和学习支持方面的原因，教育部门应通过培养学生主动学习习惯、改善教学设计、营造良好的人文环境三方面，来有效解决这一问题。     

Ranking opportunity sets in the space of functionings

We develop a ranking of compact, convex and comprehensive opportunity sets defined in the evaluative space of individual functionings. We suppose the existence of a target, that is a multi-dimensional bliss point in terms of functionings. This leads us to define concepts such as essentiality and freedomin a novel way. As a main result, we give an axiomatic characterization of the ranking obtained by minimizing the Euclidean distance between each opportunity set and the target.