A consistent estimator for the supremum of the projection index based on sliced inverse regression

To seek the nonlinear structure hidden in data points of high-dimension, a transformation related to projection pursuit method and a projection index were proposed by Li (1989, 1990 ). In this paper, we present a consistent estimator of the supremum of the projection index based sliced inverse regression technique. This estimator also suggests a method to obtain approximately the most interesting projection in the general case.     

Logistic processes involving markovian minimization

The class of logistic processes involving geometric minimization introduced by Arnold (1989) is extended by replacing the Bernoulli sequence used in the definition of the process by a Markovian (0,1) sequence. A more flexible range of dependence structures is thus introduced. Parameter estimation and related processes are discussed.     

On some special birth processes in biology

This paper presents some theorems on distributions associated with some special birth processes in biology.     

行政“前决策过程”中社会影响评价的立法确认简

近年来,关于前决策过程的考察和解析日益成为我国政策科学乃至诸社会科学相关研究领域中的重心之一。卖践表明,如“撤点并校”的行政决策历经十年所显现出的消极后果同样在不断警示着：前决策阶段走向开放形态和协同流程,并在其中引入和确立社会影响评价的必要性、重要性和紧迫性。前决策阶段进行更加富于民主性和增强科学性的程序阶段和技术方法的运用和设置,切实提高行政决策的可接受性与可实施性,是行政决策法律规范的创设与完善进程中的一个应有着力点和效用关键点。由湖南省行政程序规定以来,政府的前决策过程中进行吸纳和涵盖社会影响评价制度的立法确认,将成为我国行政程序法治化的选项和趋势。而这需要在科学的政府决策观念指导下行政决策程序规范愈加精细化的立法设计。     

中国离婚人口性别比：时期变化与空间差异

我国离婚率除存在时期差异还存在城乡差异。1990-2000年间15岁以上人口离婚率增幅显著,男性离婚率先降后升,变化幅度不大,女性自1990年起呈剧烈增长,20年增长了3倍。全国15岁以上离婚人口的性别比自1982年来出现陡降,由378降至127。2010年离婚人口性别比由城市到乡村依次升高,性别空间不均衡矛盾突出。离婚人口的年龄分布具有显著的错峰效应。乡村离婚高峰到来最早,城镇次之,再次是城市,越往后峰形越陡峻。     

高原高山区人口分布特征及影响机制研究——基于空间计量经济学视角

提出并评述了关于人口分布传统研究的三个衍生问题:空间尺度不同可能产生"人口分布悖论"现象、空间相互独立的假设不尽合理、特定空间区域人口分布的复杂性。以此为切入点,通过空间计量分析方法,探讨中国川西高原高山区人口分布特征。研究表明,全局Moran's I值为0.7404,指示川西复杂地形区人口分布有十分显著的集群特征。以川西48个县域单元为对象,建立人口密度与相关影响因子的OLS估计、SLM估计和SEM估计,经空间依赖性检验,发现空间计量回归模型明显优于普通最小二乘回归模型,表明考虑了空间依赖性的估计方法能更好的刻画人口空间分布特征;经相关判别检验,确立SLM为最优模型,其纠正了OLS模型总体上高估自然环境因子而低估经济社会因子对人口密度影响的缺陷。并以SLM估计结果为基础分析了川西人口分布特征,特别解析了川西"人口分布悖论"的事实和原因。     

Before and after science: Admissions process to Australian university social work courses

Abstract

Application processes to Australian university social work courses provide an explicit example through which to explore the influence of two schools of thought — social work as an art and as a science — on social work processes. Using admissions literature and questionnaire data provided by Australian schools of social work, this qualitative study explored the extent to which these perspectives are reflected in admissions processes. It was found that in terms of both qualities sought and techniques utilised, schools are operating essentially from a social work as science perspective, although there exists a desire to access qualities from an art perspective. This is perceived as being the result of institutional requirements, resource constraints, academic conventions and lack of knowledge about how to effectively assess the latter qualities. It is argued that social work needs to assert its unique perspectives in claiming a right to determine application processes for social work courses.     

An agent-based random-utility-maximization model to generate social networks with transitivity in geographic space

Stochastic actor-based approaches receive increasing interest in the generation of social networks for simulation in time and space. Existing models however cannot be readily integrated in agent-based models that assume random-utility-maximizing behavior of agents. We propose an agent-based model to generate social networks explicitly in geographic space which is formulated in the random-utility-maximizing (RUM) framework. The proposed model consists of a friendship formation mechanism and a component to simulate social encounters in a population. We show how transitivity can be incorporated in both components and how the model can be estimated based on data of personal networks using likelihood estimation. In an application to the Swiss context, we demonstrate the estimation and ability of the model to reproduce relevant characteristics of networks, such as geographic proximity, attribute similarity (homophily), size of personal networks (degree distribution) and clustering (transitivity). We conclude that the proposed social-network model fits seamlessly in existing large-scale micro-simulation systems which assume RUM behavior of agents.     

Ethnic inequalities at the transition from school to work in Belgium and Spain: Discrimination or self-exclusion?

In the labor market, net disadvantages of immigrants, so-called “ethnic penalties”, may stem from rather different sources, among them discrimination by employers or self-exclusion processes. This paper attempts to indirectly disentangle these two mechanisms by studying ethnic penalties from a time-related perspective. Using the EULFS 2000 ad hoc module on school-to-work transitions, a comparative event-history analysis of entry into stable higher status employment is conducted for two European countries, Belgium and Spain. These countries differ considerably in their immigration contexts and patterns of school-to-work transitions, requiring different hypotheses about the relevance of the self-exclusion mechanism. The results show that in Belgium ethnic penalties for non-EU immigrants exist and remain constant irrespective of the length of the job search. In Spain the gap between non-EU immigrants and the native-born is even more pronounced and, importantly, increases significantly over time. This leads to the conclusion that discrimination seems to be relevant in both contexts and that self-exclusion resulting from early abandonment of job search activities is a further important factor in Spain.