The breakdown and influence properties of outlier rejection-plus-mean procedures

In a recent paper, Hampel (1985) studied the properties of rejection-plus-mean procedures as estimators of a location parameter. He reported that these procedures have low breakdown and high variance. In this article it is pointed out that these results are due to the outliers being rejected in a forwards-stepping manner, and when a more appropriate backwards-stepping approach is used, rejection-plus-mean procedures lead to estimators with high breakdown and high variance. In this article it is pointed out that these results are due to the outliers being rejected in a forwards-stepping manner, and when a more appropriate backwards-stepping approach is used, rejection-plus-mean procedures lead to estimator with high breakdown and redescending theoretical influence function.     

元代的回回乐器与乐曲

本文就元代东传的火不思、兴隆笙、七十二弦琵琶等阿拉伯-伊斯兰乐器进行了详细考述,并论述了东来回回艺人在华的活动及回回乐曲的传播与影响。     

十九世纪蒙汉文化交流的一面镜子--《泣红亭》及其汉译本述评

本文就蒙古族古典文学名著<一层楼>的姊妹篇<泣红亭>的创作受汉文化及<镜花缘>等古典文学影响的情形进行了简略评述,并着重对<泣红亭>汉译本的得失进行了分析评论.     

关于霍集斯的几个问题

霍集斯(1710年-1781年)①,乌什维吾尔人,清朝统一新疆过程中归顺,曾扮演清朝军政生活中的重要角色,并对清朝统一新疆大业的顺利进行产生过重要影响。本文拟就霍集斯的宗教派别,其家族在新疆的地位,其家族投清对清朝统一新疆大业的影响及投清后的授官封爵情况等问题进行浅述,以期弥补这方面研究的不足。     

微技术传播对青年人信仰的影响研究

以微博和微信为代表的微技术深刻影响着青年人的思维方式、行为方式、价值方式。同时,微技术在传播信仰过程中改变了传统的信仰格局,打破了政治输入和输出的传统信仰架构。青年不但成为了微技术信仰语言的创造者,也有着强烈的信仰平等诉求。在微技术时代,实现信仰治理的优化刻不容缓。     

我国粮食价格形成机制沿革的历史回顾与探讨

粮食价格形成机制的核心是政府及其市场主体在粮食价格水平决定中的作用机制.改革开放前,政府影响力在我国粮食价格形成中起着决定性作用.改革开放后,我国粮食价格形成机制的变迁以不断调适政府对粮食价格水平决定的影响力为主线,经历了从政府直接控制价格水平到间接影响价格水平形成的转折.总体而言,在粮食供求关系偏紧时,往往通过政府强势的价格影响力来实现粮食增产,而当粮食供求关系偏松时,政府强势影响价格的弊端就会累积性呈现.从改革开放以来粮食价格形成机制的变化及其调整来看,我国一直没有找到粮食供求关系偏松状况下有效的粮食价格形成机制.未来我国粮食价格形成机制改革的关键是政府在粮食价格水平决定中应发挥怎样的作用,而不是放任粮食市场自发形成价格,否则我国粮食市场过度波动难以避免,粮食生产长期稳定发展难免受到影响.     

毛竹林单户经营规模效率及影响因素分析--基于福建三明的调查

基于福建省三明市的163户农户调查数据,采用DEA-Tobit模型分析了毛竹林地经营规模效率及其影响因素。在效率测算方面,福建省样本调查地区单户经营的毛竹林的总体规模效率平均为0.91,而林地平均规模效率为0.86。可以看出,毛竹林总体经营规模效率较高,但林地这一要素的规模效率较低。单户经营林地最优规模为60~70亩(4~4.67 hm2),总体投入产出要素配置比例相对协调,但中小规模经营面积的农户经营效率仍有待提高。在分析影响因素方面,家庭劳动力数量、从事林业经营活动经验、林地面积与毛竹林经营规模效率存在正相关关系;户主性别、年龄、生产周期投工费用与规模效率呈反向变动关系。提出因地制宜确立林地经营效率最优适度规模、加大力度扶持中小规模林地经营农户、加强林业经营者队伍质量建设等建议。     

公立高校教师心理契约违背的影响因素分析

基于心理契约理论,对高校教师心理契约形成过程、心理契约违背发生、发生心理契约违背对高校教师行为的具体影响等方面进行了深入分析。先后选取了东中西部十余所公立高校的230名高校教师进行调查,结果发现：影响公立高校教师心理契约违背的重要因素主要包括稳定的工作保障、良好的行政服务和高效完成工作任务等九项重要指标。     

Influence diagnostics for the Weibull-Negative-Binomial regression model with cure rate under latent failure causes

In this paper, we propose a flexible cure rate survival model by assuming that the number of competing causes of the event of interest follows the Negative Binomial distribution and the time to event follows a Weibull distribution. Indeed, we introduce the Weibull-Negative-Binomial (WNB) distribution, which can be used in order to model survival data when the hazard rate function is increasing, decreasing and some non-monotonous shaped. Another advantage of the proposed model is that it has some distributions commonly used in lifetime analysis as particular cases. Moreover, the proposed model includes as special cases some of the well-know cure rate models discussed in the literature. We consider a frequentist analysis for parameter estimation of a WNB model with cure rate. Then, we derive the appropriate matrices for assessing local influence on the parameter estimates under different perturbation schemes and present some ways to perform global influence analysis. Finally, the methodology is illustrated on a medical data.     

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.