Discriminant coordinates analysis for multivariate functional data

Abstract

One of the basic statistical methods of dimensionality reduction is analysis of discriminant coordinates given by Fisher (1936 Fisher, R. A. 1936. The use of multiple measurements in taxonomic problem. Annals of Eugenics 7 (2):179–88. doi:10.1111/j.1469-1809.1936.tb02137.x.[Crossref] , [Google Scholar]) and Rao (1948). The space of discriminant coordinates is a space convenient for presenting multidimensional data originating from multiple groups and for the use of various classification methods (methods of discriminant analysis). In the present paper, we adapt the classical discriminant coordinates analysis to multivariate functional data. The theory has been applied to analysis of textural properties of apples of six varieties, measured over a period of 180?days, stored in two types of refrigeration chamber.     

Simultaneous sparse model selection and coefficient estimation for heavy-tailed autoregressive processes

We propose a sparse coefficient estimation and automated model selection procedure for autoregressive processes with heavy-tailed innovations based on penalized conditional maximum likelihood. Under mild moment conditions on the innovation processes, the penalized conditional maximum likelihood estimator satisfies a strong consistency, O_P(N^?1/2) consistency, and the oracle properties, where N is the sample size. We have the freedom in choosing penalty functions based on the weak conditions on them. Two penalty functions, least absolute shrinkage and selection operator and smoothly clipped average deviation, are compared. The proposed method provides a distribution-based penalized inference to AR models, which is especially useful when the other estimation methods fail or under perform for AR processes with heavy-tailed innovations [Feigin, Resnick. Pitfalls of fitting autoregressive models for heavy-tailed time series. Extremes. 1999;1:391–422]. A simulation study confirms our theoretical results. At the end, we apply our method to a historical price data of the US Industrial Production Index for consumer goods, and obtain very promising results.     

学前儿童基于重量和声音进行因果推理的发展研究

儿童的推理能力历来都是考察儿童认知发展的重点。本研究探讨了在多种属性刺激下3~5岁儿童基于重量和声音进行 因果推理的表现。结果发现：4岁和5岁儿童选择正确目标物的准确率显著高于3岁儿童；和同时使用声音与重量判断目标物相 比，儿童在单独使用重量或声音的情况下更容易区分目标物。总之，儿童因果推理能力发展的关键期在4岁并且当任务难度较高 的情况下其因果机制极易受到干扰。     

A quantile-based study on ageing intensity function

Jiang, Ji, and Xiao (2003 Jiang, R., P. Ji, and X. Xiao. 2003. Aging property of unimodal failure rate models. Reliability Engineering and System Safety 79(1):113–6.[Crossref], [Web of Science ®] , [Google Scholar]) has introduced a quantitative measure known as the ageing intensity function for evaluating the ageing properties of a component/system. In recent years, there has been a great interest on the study of quantile function, an equivalent alternative to the distribution function approach. Unlike the distribution function approach, the quantile method possess some unique properties (see Gilchrist 2000 Gilchrist, W. 2000. Statistical modelling with quantile functions. Boca Raton, Florida: Chapman and Hall/CRC.[Crossref] , [Google Scholar], Nair, Sankaran, and Balakrishnan 2013 Nair N. U., P. G. Sankaran, N. Balakrishnan. 2013. Quantile-based reliability concepts. In: Quantile-Based Reliability Analysis. Statistics for Industry and Technology. New York, NY: Birkhäuser.[Crossref] , [Google Scholar]). Motivated with this, in the present paper we introduce a quantile-based ageing intensity function and study its various ageing properties. We also study some stochastic comparison of random variables based on the proposed measure.     

Stochastic properties of the mixed accelerated hazard models

The accelerated hazard model in survival analysis assumes that the covariate effect acts the time scale of the baseline hazard rate. In this paper, we study the stochastic properties of the mixed accelerated hazard model since the covariate is considered basically unobservable. We build dependence structure between the population variable and the covariate, and also present some preservation properties. Using some well-known stochastic orders, we compare two mixed accelerated hazards models arising out of different choices of distributions for unobservable covariates or different baseline hazard rate functions.     

基于层次分析法的股票内在价值研究

分析股票的内在价值有利于投资者做出准确的投资判断,规避投资风险,获取稳定收益。采用层次分析法对影响股票内在价值的各项指标进行分类排序,构建了股票内在价值评估的递阶层次结构和综合评价模型,并结合实际案例对该模型进行了验证。     

高职可持续发展的基础：“双师型”师资队伍建设

加强教师队伍建设是教育事业发展最重要的基础工作。高等职业教育同时具有＂高等教育＂和＂职业教育＂的双重属性,因此加强＂双师型＂师资队伍建设是高等职业教育事业发展的最重要的基础工作,对高等职业教育的可持续发展具有十分重要的意义。     

内生和外生视角下组织激励问题的研究综述及展望

当前,对外生和内生激励的研究已取得了一定的成果。外生激励与内生激励存在着概念、本质和功效上的差异。内生激励是指人们发现该行为本身有趣并且可以从行为中获得满足,而外生激励是指人们在行为发生之后,会从与行为本身无关的一些外界回报（如物质奖励）中获得满足,两种激励机制下的管理风格各不相同。外生激励对内生激励可能存在着“挤入”或“挤出”两种效应。随着个体对外部的认知能力提升以及自我的发展的需要,外生激励会逐步内化。未来应该在个体感知的外生激励信息反馈、外生激励内化的情景因素、外生激励内化的个体因素、外生激励与内生激励的组织实证研究这四个方向进一步加以研究。     

橡胶缓冲垫受偏心冲击特性的数值研究

气动钉枪缓冲垫在工作过程中常受到来自枪针组件的偏心冲击。文章以气动钉枪工作状态为基础,通过ANSYS/LS-DYNA软件对缓冲垫承受偏心冲击的特性进行数值模拟研究。研究表明,在偏心冲击下,橡胶缓冲垫的损坏将加剧,提高枪针组件的对中性将有助于橡胶缓冲垫寿命的提高