我国流动人口的流入地分布变动趋势研究

利用1982年以来的历次全国人口普查和1%人口抽样调查的数据,本文从区域、省份、城市等层面分析了流动人口流入地分布的变动趋势。流动人口的流入地分布呈现明显的集中趋势。从区域层面来说,流动人口越来越向东部地区集中,越来越向东部和南部沿海地区集中;从省级层面来说,流动人口越来越集中流向少数省份,前5个流动人口最多的省(市、区)吸纳了全国一半的流动人口;从城市层面来说,流动人口越来越集中流向少数城市,表现出突出的极化现象;进入新世纪以来,我国正在形成一个由35个左右城市构成的沿海城市带,它们吸收了全国半数以上的流动人口。流动人口流入地分布的这种集中趋势将会继续保持下去,此乃制定与流动人口相关政策和制度的基本出发点和前提。     

国有股和法人股对公司业绩的影响--公用事业型上市公司的实证研究

公司的股份集中于少数几个大股东手中是中国公司股权结构的一个普遍特征,研究这些大股东如何凭借其持股地位影响公司业绩是中国公司股权结构研究的一个非常重要的问题.本文选取了在上交所上市的公用事业型公司1998年至2002年的平行数据进行实证研究,结果表明,法人股对公司业绩有积极影响,国有股对公司业绩的影响视具体情况而定.     

Saddlepoint approximations for some models of circular data

In this article we provide saddlepoint approximations for some important models of circular data. The particularity of these saddlepoint approximations is that they do not require solving the saddlepoint equation iteratively, so their evaluation is immediate. We first give very accurate approximations to P-values, critical values and power functions for some optimal tests regarding the concentration parameter under wrapped symmetric α-stable and circular normal models. Then, we consider an approximation to the distribution of a projection of the two-dimensional Pearson random walk with exponential step sizes.     

Concentration Ellipsoids,Their Planes of Support,and the Linear Regression Model

The relationship between the concentration ellipsoid of a random vector and its planes of support is exploited to provide a geometric derivation and interpretation of existing results for a general form of the linear regression model. In particular, the planes of support whose points of tangency to the ellipsoid are contained in the range (or column space) of the design matrix are the source of all linear unbiased minimum variance estimators. The connection between this idea and estimators based on projections is explored, as is also its use in obtaining and interpreting some existing relative efficiency results.     

与收入相关的老人健康不平等及其分解——基于中国城镇和农村的经验研究

本文使用“中国老年人健康长寿影响因素调查”（CLHLS）数据,测度了中国老人健康不平等程度,重点计算了收入、婚姻状况、居住安排等因素对健康不平等的贡献。回归基础上的集中系数及其分解结果显示：我国存在亲富人的健康不平等,高收入人群的健康状况更好;城镇地区,健康不平等主要的贡献因素为收入、婚姻状况、医疗保险、经常锻炼,居住安排对健康不平等的贡献为负。农村地区,收入因素对于健康不平等的贡献最大,这就意味着消除农村健康不平等的关键是要降低收入不平等。在城镇和农村地区医疗保险的不平等程度更甚,进一步强化了健康不平等。因此如果政策想要降低健康不平等,首先要降低穷人获得医疗保险的经济门槛,增加医疗保健服务的可及性。     

Low-pass filter design using locally weighted polynomial regression and discrete prolate spheroidal sequences

The paper concerns the design of nonparametric low-pass filters that have the property of reproducing a polynomial of a given degree. Two approaches are considered. The first is locally weighted polynomial regression (LWPR), which leads to linear filters depending on three parameters: the bandwidth, the order of the fitting polynomial, and the kernel. We find a remarkable linear (hyperbolic) relationship between the cut-off period (frequency) and the bandwidth, conditional on the choices of the order and the kernel, upon which we build the design of a low-pass filter.The second hinges on a generalization of the maximum concentration approach, leading to filters related to discrete prolate spheroidal sequences (DPSS). In particular, we propose a new class of low-pass filters that maximize the concentration over a specified frequency range, subject to polynomial reproducing constraints. The design of generalized DPSS filters depends on three parameters: the bandwidth, the polynomial order, and the concentration frequency. We discuss the properties of the corresponding filters in relation to the LWPR filters, and illustrate their use for the design of low-pass filters by investigating how the three parameters are related to the cut-off frequency.     

中国育龄妇女生育集中度变化分析——基于“五普”、“六普”数据

新中国成立以来,结束了上千年的封建制度给妇女带来的桎梏,妇女的社会地位有了明显的提升,具体表现在社会活动的参与率有了显著的提高,同时妇女在生育行为方面也发生了巨大的变化。本文利用最近两次中国人口普查数据来分析育龄妇女的生育集中度变化情况,并以此对中国目前TFR很低的现象做了解释,据此推断中国在未来几年的时间,总和生育率在一定程度上会呈上升的变化趋势,但不可能在短期内回升到更替水平。     

社会服务供给集约化发展思路探索

针对我国目前社会服务供给主体发展现状和社会服务供给特性,结合市场集中度和集约化管理理论,分析我国社会服务供给主体存在的主要问题,论述社会服务供给市场集中度与社会服务供给集约化的关系,提出通过降低准入门槛、鼓励主体竞合、强化规模运营、培育大型主体、理顺主体关系、完善竞争机制及优化市场结构等策略与措施,来推动社会服务供给集约化管理。     

Half-normal approximation for statistics of symmetric simple random walk

In 2013, Döbler used Stein’s method to obtain the uniform bounds in half-normal approximation for three statistics of a symmetric simple random walk; the maximum value, the number of returns to the origin and the number of sign changes up to a given time n. In this paper, we give the non-uniform bounds for these statistics by using Stein’s method and the concentration inequality approach.