老龄化对储蓄和社会养老保障的影响研究

本文从一个两期的世代交叠模型入手,分析了人口老龄化对储蓄和社会养老保障支出的影响。在此基础上运用动态GMM模型对我国2000～2008年地区面板数据进行实证分析。研究结果表明:第一,人均居民储蓄滞后项对基期储蓄的影响作用较大且高度显著;当期老年人口抚养比对人均居民储蓄的影响为负,上期老年人口抚养比对居民储蓄并没有显著影响。第二,人均养老保障支出滞后项对当期人均养老保障支出影响作用较大且高度显著;当期老年人口抚养比对人均养老保障支出有促进作用,而上期老年人口抚养比抑制了人均养老保障支出的增加。     

试论时期总和生育率、终身生育率与政策生育率的关系

通过对总和生育率(TFR)、终身生育率(CFR)与政策生育率(PFR)的概念及相关数据分析,论证总和生育率与政策生育率是完全不同的概念,不可直接比较。在特定条件下TFR、CFR和政策生育率会产生差异,在一个国家生育水平下降的历史时期,TFR必然小于当年49岁组女性的CFR;"超生率"、"未婚率"、"未育率"和"不孕率"的变化,决定了政策生育率与终身生育率的差异。借鉴日本经济与人口发展相关数据,可以相信由平均初婚年龄推迟、女性有偶率下降导致的生育水平下降很可能成为对我国人口均衡发展的最大潜在威胁。因此,当前以及今后相当的时期内,我国的政策生育率应高于1.8。     

“转城村”儿童忽视现状及影响因素分析

城市化进程中,"转城村"数量的增加引起众多的经济和社会问题,由此带来的儿童忽视问题越来越严重。采用分层整群抽样方法,对河北省秦皇岛市代表性"转城村"的儿童及家长进行问卷调查,统计分析结果表明,"转城村"儿童的教育忽视较为严重,影响儿童忽视率与忽视度的主要因素有父母的文化程度、家庭月均收入、抚养人与孩子关系等因素。     

Estimating monotone convex functions via sequential shape modification

We propose a sequential method to estimate monotone convex functions that consists of: (i) monotone regression via solving a constrained least square (LS) problem and (ii) convexification of the monotone regression estimate via solving a uniform approximation problem with associated constraints. We show that this method is faster than the constrained LS method. The ratio of computation time increases as data size increases. Moreover, we show that, under an appropriate smoothness condition, the uniform convergence rate achieved by the proposed method is nearly comparable to the best achievable rate for a non-parametric estimate which ignores the shape constraint. Simulation studies show that our method is comparable to the constrained LS method in estimation error. We illustrate our method by analysing ground water level data of wells in Korea.     

Evaluating lifetime performance for the Pareto model with censored and imprecise information

A lifetime capability index L _tp has been proposed to measure the business lifetime performance, wherein output lifetime measurements are assumed to be precise from the Pareto model with censored information. In the present study, we study a more realistic situation where the lifetime output data are imprecise. The approach developed by Buckley [Fuzzy system, Soft Comput. 9 (2005), pp. 757–760; Fuzzy statistics: Regression and prediction, Soft Comput. 9 (2005), pp. 769–775] incorporated with some extensions (a set of confidence intervals, one on top of the other), is used to construct the triangular-shaped fuzzy number for the fuzzy estimate of the L _tp. With the sampling distribution of the unbiased estimator of the L _tp, two useful fuzzy inference criteria, its critical value and fuzzy p-value are obtained to assess the lifetime performance. The presented methodology can handle the lifetime performance assessment on the condition that sample lifetime data are involved with imprecise information, classifying the lifetime performance with the three-decision rule. With different preset requirements and a certain degree of imprecise data, we also develop a four quadrants decision-making plot where managers can easily simultaneously visualize several important features of lifetime performance for making a decision. An example of business lifetime data is given to illustrate the applicability of the proposed method.     

A- and D-optimal progressive Type-II censoring designs based on Fisher information

Fisher information about multiple parameters in a progressively Type-II censored sample is discussed. A representation of the Fisher information matrix in terms of the hazard rate of the baseline distribution is established which can be used for efficient computation of the Fisher information. This expression generalizes a result of Zheng and Park [On the Fisher information in multiply censored and progressively censored data, Comm. Statist. Theory Methods 33 (2004), pp. 1821–1835] for Fisher information about a single parameter. The result is applied to identify A- and D-optimal censoring plans in a progressively Type-II censored experiment. For illustration, extreme value, normal, and Lomax distributions are considered.     

Power and stability comparisons of multiple testing procedures with false discovery rate control

High-throughput data analyses are widely used for examining differential gene expression, identifying single nucleotide polymorphisms, and detecting methylation loci. False discovery rate (FDR) has been considered a proper type I error rate to control for discovery-based high-throughput data analysis. Various multiple testing procedures have been proposed to control the FDR. The power and stability properties of some commonly used multiple testing procedures have not been extensively investigated yet, however. Simulation studies were conducted to compare power and stability properties of five widely used multiple testing procedures at different proportions of true discoveries for various sample sizes for both independent and dependent test statistics. Storey's two linear step-up procedures showed the best performance among all tested procedures considering FDR control, power, and variance of true discoveries. Leukaemia and ovarian cancer microarray studies were used to illustrate the power and stability characteristics of these five multiple testing procedures with FDR control.     

Estimation of the extended Weibull parameters and acceleration factors in the step-stress accelerated life tests under an adaptive progressively hybrid censoring data

ABSTRACT

Based on the tampered failure rate model under the adaptive Type-II progressively hybrid censoring data, we discuss the maximum likelihood estimators of the unknown parameters and acceleration factors in the general step-stress accelerated life tests in this paper. We also construct the exact and unique confidence interval for the extended Weibull shape parameter. In the numerical analysis, we describe the simulation procedures to obtain the adaptive Type-II progressively hybrid censoring data in the step-stress accelerated life tests and present an experimental data to illustrate the performance of the estimators.     

从及物性视角看英语“中性”新闻

系统功能语言学中的及物性理论是对新闻语篇进行批评性分析的有效工具,试图利用这一工具对鲜有问津的貌似客观公正的"中性"自然灾害类报道进行分析,揭示出语言、意识形态和权利之间的密切关系存在于任何形式的新闻语篇中。以期读者提高批评阅读意识,增强在阅读国外强势媒体新闻时的判断力,从而有效抵御西方话语霸权对中国本土文化的侵蚀。     

上海城市街道命名的语言理据研究

上海城市街道命名的语言理据来自行政地名、地理实体、经济生活中的典型事例、历史人物与历史事件以及社会需求等,是近现代时期上海的自然环境信息和人文环境信息在语言中的沉淀,是语言社会生活的一部分。