The approximate null distribution of the likelihood ratio test for a mixture of two bivariate normal distributions with equal co variance

We define the mixture likelihood approach to clustering by discussing the sampling distribution of the likelihood ratio test of the null hypothesis that we have observed a sample of observations of a variable having the bivariate normal distribution versus the alternative that the variable has the bivariate normal mixture with unequal means and common within component covariance matrix. The empirical distribution of the likelihood ratio test indicates that convergence to the chi-squared distribution with 2 df is at best very slow, that the sample size should be 5000 or more for the chi-squared result to hold, and that for correlations between 0.1 and 0.9 there is little, if any, dependence of the null distribution on the correlation. Our simulation study suggests a heuristic function based on the gamma.     

Empirical bayes methods for a two-way multiplicative-interaction model

Empirical Bayes methods are used to estimate cell probabi-lities under a multiplicative-Interaction model for a two-way contingency table. The methods assign uniform and normal priors with unknown variances to the main effects and the separable scores. A priori the analysis assumes exchangeability of sets of parameters. The unknown variance components are estimated empirically from the data via the EM algorithm as discussed by Laird (1978)and Dempster, Laird and Rubin (1977). An example Is Included.     

象征性社会秩序探究

本研究探究了一种不同于当下主流社会秩序的象征性社会秩序,其所表现出的缓冲社会变迁剧烈程度、维持社会整合状态的社会作用,具有一定的积极意义。但这种象征性社会秩序及与之伴生的生产机制的存在,会在一定程度上延缓甚至阻碍社会秩序的更替与进步,并形成对当下主流社会秩序的冲击和影响,进而成为众多社会问题的直接根源。     

TOA折叠平面特征点无监督聚类

为提高雷达脉冲分选效率以及将分选和辐射源识别统一完成,探索仅在时域进行重频分选与辐射源特征提取.将雷达脉冲序列的到达时间(TOA)在时间上进行折叠,使得交错在一起的雷达脉冲序列在TOA折叠平面上所形成点迹图.不同雷达由于重频特征不同使得属于一部雷达的脉冲在TOA折叠平面上的点迹形成较强的规律性.文中应用改进的方法通过对点迹的聚类来完成对上述规律的提取,实现将雷达脉冲分选和重频特性识别统一完成.     

农村企业环境成本与社会效益评价探析

随着经济的发展,环境污染越来越严重。环境成本与经济效益的关系一直是农村企业战略管理研究中所关注的重要问题。以企业环境成本的核算与控制为切入点,制定出以绿色供应链为基础的控制方法,将有效建立农村企业的社会效益评价体系。     

Do social allowance transfers crowd out private transfers? An analysis of responses among elderly households in Taiwan

Chuang JCC. Do social allowance transfers crowd out private transfers? An analysis of responses among elderly households in Taiwan This article examines whether public transfers ‘crowd out’ private inter‐household transfers in Taiwan, focusing on two old age social allowance schemes (old age allowance and old age farmer allowance) during the 2002–2008 period. This study used a data set from the Survey of Family Income and Expenditure in Taiwan. Empirical evidence suggests that Taiwanese donors are strongly motivated by altruism, and that the increase of public transfers will crowd out private transfers, and vice versa. Besides, altruism is more likely to dominate among poorer elderly recipients, whereas the exchange motive would dominate among richer recipients. Thus, the response of Taiwanese donors is likely to neutralise the distributional impact of public transfers. Finally, the elderly are not a homogenous group, and the effect of public transfers on private transfers varies significantly by household characteristics, in particular depending on age, marital status and living arrangements.     

“两课”教学中大学生考评体系构建的基本思路

“两课”教学传统考评模式,以理论知识为主要内容,以考试为主要手段,不利于“两课”教学目标的实现。客观、公正、科学的“两课”考评,主要内容应包含政治理论素养、思想品德修养、创新精神与实践能力。考评方式应做到动态评价与静态评价相结合,校内评价与校外评价相结合,相对评价与绝对评价相结合,教师评价与自评互评相结合,定性评价与定量评价相结合。     

网络信息产品免费定价策略研究

网络信息厂商的利润有两个来源,一是来自产品本身的直接利润,这与消费者的支付意愿相关;二是以其他间接方式获得,这通常与用户数量相关,因此网络信息产品的定价策略必须同时解决获得用户数量和区分消费者支付意愿这两个问题.网络外部性、体验式商品以及特殊的成本结构等技术特性使网络信息产品的定价和竞争策略与传统行业有本质区别,如何获得用户数量和有效区分不同消费者的支付意愿是网络信息产品定价策略必须解决的两个问题.基于零边际成本和低产品差异化成本,免费定价策略能够首先解决体验式商品的定价难题,获得用户数量,然后通过多种形式对消费者支付意愿进行区分,以直接或间接的方式获得利润.免费定价策略不同于传统行业中的低价竞争,是一种基于网络信息产品技术特性的有效竞争方式.     

Lessons from meta‐analyses of randomized clinical trials for analysis of distributed networks of observational databases

Networks of constellations of longitudinal observational databases, often electronic medical records or transactional insurance claims or both, are increasingly being used for studying the effects of medicinal products in real‐world use. Such databases are frequently configured as distributed networks. That is, patient‐level data are kept behind firewalls and not communicated outside of the data vendor other than in aggregate form. Instead, data are standardized across the network, and queries of the network are executed locally by data partners, and summary results provided to a central research partner(s) for amalgamation, aggregation, and summarization. Such networks can be huge covering years of data on upwards of 100 million patients. Examples of such networks include the FDA Sentinel Network, ASPEN, CNODES, and EU‐ADR. As this is a new emerging field, we note in this paper the conceptual similarities and differences between the analysis of distributed networks and the now well‐established field of meta‐analysis of randomized clinical trials (RCTs). We recommend, wherever appropriate, to apply learnings from meta‐analysis to help guide the development of distributed network analyses of longitudinal observational databases.     

将德育进行到底——小、中、大学德育衔接管见

德育居于学校教育的首位。要改变当前小、中、大学三个阶段德育不相衔接的状况 ,应从德育教材、道德认识、道德责任、道德人格四个方面的衔接着手 ,从而形成三个阶段相互联系、栉比鳞次、层层提升的学校教育的德育系统