Mixtures of Gaussian copula factor analyzers for clustering high dimensional data

Mixtures of factor analyzers is a useful model-based clustering method which can avoid the curse of dimensionality in high-dimensional clustering. However, this approach is sensitive to both diverse non-normalities of marginal variables and outliers, which are commonly observed in multivariate experiments. We propose mixtures of Gaussian copula factor analyzers (MGCFA) for clustering high-dimensional clustering. This model has two advantages; (1) it allows different marginal distributions to facilitate fitting flexibility of the mixture model, (2) it can avoid the curse of dimensionality by embedding the factor-analytic structure in the component-correlation matrices of the mixture distribution.An EM algorithm is developed for the fitting of MGCFA. The proposed method is free of the curse of dimensionality and allows any parametric marginal distribution which fits best to the data. It is applied to both synthetic data and a microarray gene expression data for clustering and shows its better performance over several existing methods.     

Values and happiness among Asian adolescents: a cross-national study

Despite policy efforts to increase adolescent happiness, their impact has been unsatisfactory. Their limited impact may be rooted from a discrepancy between values that adolescents pursued and those that the policies were based on. To provide policy implications, our study aims to identify prevailing values for South Korean, Japanese, and Chinese adolescents and to examine the relationship between the values and self-rated happiness (SRH). A cross-sectional study was conducted using survey data collected on approximately 2000 middle and high school students (7th to 12th school grade) from each country in 2008. Firstly, an explanatory factor analysis was conducted to identify salient adolescent values from each country. Subsequently, a multiple logistic regression analysis was conducted for each population group to examine the relationship between the identified values and adolescent SRH after controlling for sociodemographic characteristics. We found that benevolence and altruism were positively associated with adolescent SRH in all three population groups. Patriarchy was associated with SRH positively in Chinese yet inversely in Japanese. Success pursuit was inversely associated with SRH in Korean. Policy efforts based on values of communities or social harmony may benefit adolescents’ SRH in these three countries.     

Adaptation of the short version of the Psychological Capital Questionnaire (PCQ-12) into Spanish / Adaptación al español de la versión reducida del Cuestionario de Capital Psicológico (PCQ-12)

Psychological capital (PsyCap) has been a topic of increasing interest in the last decade. However, there is a lack of validated instruments in Spanish to map PsyCap and its consequences for individuals’ well-being. Consequently, the goal of this study is to adapt the 12-item short version of the Psychological Capital Questionnaire (PCQ-12) to the Spanish context by analysing its internal consistency and reliability, factor solution and external validity. Results indicated that the PCQ-12 exhibited good Cronbach’s alpha (.87) and omega coefficient (.93) values in a sample from a vehicle inspection company (n = 798). As expected, results also revealed that a second-order factor structure provided the best fit. Moreover, PsyCap is associated with increased job engagement (β = .579; R²_adjusted = .333), decreased job burnout (β = ?.409; R²_adjusted = .166), and lower psychological distress (β = ?.349; R²_adjusted = .121) (all p < .01), which provided additional support for using the PCQ-12 in the Spanish context. Implications for theory and practice are discussed.     

On the mathematics of the Jeffreys–Lindley paradox

This paper is concerned with the well known Jeffreys–Lindley paradox. In a Bayesian set up, the so-called paradox arises when a point null hypothesis is tested and an objective prior is sought for the alternative hypothesis. In particular, the posterior for the null hypothesis tends to one when the uncertainty, i.e., the variance, for the parameter value goes to infinity. We argue that the appropriate way to deal with the paradox is to use simple mathematics, and that any philosophical argument is to be regarded as irrelevant.     

中国旅游上市公司全要素生产率研究

旅游上市公司是旅游业发展的微观主体,其全要素生产率全面反映了该行业的实际经营效率和发展趋势。本文基于Malmquist指数探讨了20家中国旅游上市公司2004-2009年的全要素生产率。Malmquist指数及其分解结果显示:中国旅游上市公司Malmquist指数年均增长率为-0.4%,其中纯技术效率的增长显著,年均增幅为1.3%;时间跨度层面,中国旅游上市公司的全要素生产率的年度波动性较大。此外,样本中旅游上市公司Malmquist指数与营业收入增长率未能兼顾;2008-2009年度粗放型增长的特征显著。     

Marginal likelihood estimation from the Metropolis output: tips and tricks for efficient implementation in generalized linear latent variable models

The marginal likelihood can be notoriously difficult to compute, and particularly so in high-dimensional problems. Chib and Jeliazkov employed the local reversibility of the Metropolis–Hastings algorithm to construct an estimator in models where full conditional densities are not available analytically. The estimator is free of distributional assumptions and is directly linked to the simulation algorithm. However, it generally requires a sequence of reduced Markov chain Monte Carlo runs which makes the method computationally demanding especially in cases when the parameter space is large. In this article, we study the implementation of this estimator on latent variable models which embed independence of the responses to the observables given the latent variables (conditional or local independence). This property is employed in the construction of a multi-block Metropolis-within-Gibbs algorithm that allows to compute the estimator in a single run, regardless of the dimensionality of the parameter space. The counterpart one-block algorithm is also considered here, by pointing out the difference between the two approaches. The paper closes with the illustration of the estimator in simulated and real-life data sets.     

正常商品的替代效应与收入效应研究

目前,国内外的微观经济学教科书中,关于正常商品的替代效应和收入效应的图形说明很不一致。主要是关于正常商品降价后新的预算线上的均衡点和原始预算线上的均衡点的位置不同。为此,在给定消费者效用函数和预算线方程的基础上,通过对正常商品降价(涨价)后带来的总效应、替代效应以及收入效应进行数理分析,使人们达到完整准确地理解和掌握正常商品的替代效应和收入效应的目的。     

商业信用风险管理绩效影响因素的实证分析

近年来,Jianmin Jia等学者对"我国信用风险管理现状"及其相关问题进行研究,取得一定的研究成果,但相应研究中存在着"简单使用线性回归,未能消除变量间的相互影响"等局限。基于对已有相关研究成果的评析,并运用因子分析和Pearson相关分析方法,对我国商业信用风险管理绩效的影响因素进行实证研究。研究表明:商业信用风险管理绩效的关键影响因素为"信用管理职能设置"、"客户资信评估"和"信用政策制定",我国企业应从"完善信用风险管理职能"、"改善信息不对称状况"和"提高信用政策制定水平"三方面提高风险管理绩效。     

西部地区工业竞争力综合评价

本文基于面板数据的因子分析,从经济效益、科技与人才、能源与环保三个维度对西部十一省工业综合竞争力进行评估。结果表明,西部地区工业竞争力总体水平不高且不平衡明显。其中四川、重庆、陕西、广西、云南是西部具有较强的工业竞争力的地区,而贵州、甘肃、内蒙古、新疆、青海、宁夏竞争力较弱。因此要有针对性地实施发展规划,以促进西部地区工业差距缩小与总体发展水平的提升。     

A bibliographic study of public relations in Spanish media and communication journals, 2000–2012

This study analyses the trends and visibility of research on public relations in the most relevant Spanish media and communication journals between the years 2000 and 2012. Bibliometrics and content analysis are used to show the reduced presence of articles on public relations in these publications. A trend towards gender parity in authorship is confirmed in the sample, as well as a plurality of universities and a variety of research themes. The study also proves preference for generic questions rather than for specialised topics. Another finding is that almost one fourth of the specific articles on this discipline do not contain the term “public relations”. This can hint towards the need to have a specific high-impact publication on public relations to bring together and provide visibility to the contributions of researchers in this field.