农村地区工业化与人力资本的作用——以河南省回乡创业为例

人力资本对于农村地区实现工业化和现代化至关重要,但所需要的人力资本从哪里来?近年来"回乡创业"已经成为继"民工潮"之后又一个新现象.从农村来到城市的农民工带着在城市工作中获得的资金、技术、知识和企业家精神等,回乡创建自己的企业.回乡者带来的人力资本对农村地区的创业活动(或创建企业的发展)做出了重大贡献.对地方政府来说,鼓励和支持回乡创业是促进农村地区实现工业化和现代化的重要途径.     

A Multisample Rank Test for Location-Scale Parameters

One of the multisample problems is discussed in this article. A new multisample rank tests based on a k-sample Baumgartner statistic are proposed for testing the location-scale parameters. The exact critical values of proposed statistics are calculated. Simulations are used to investigate the power of proposed statistics for various population distributions.     

寻找儒学者姜沆的足迹

姜沆(1567-1618),朝鲜李朝时代的儒学者,出生于全罗道灵光郡流峰里,1597年9月23日被日军囚禁.他著有《看羊录》痛斥日本侵略者的罪恶,姜沆以虏囚之身,用他的学识和精神给日本留下了伟大的文化之光.     

Positive-definite modification of a covariance matrix by minimizing the matrix $$\ell_{\infty}$$ ℓ ∞ norm with applications to portfolio optimization

AStA Advances in Statistical Analysis - The covariance matrix, which should be estimated from the data, plays an important role in many multivariate procedures, and its positive definiteness...     

北京和东京居民的时间分配比较研究

本文以时间作为测量人类生活的计量单位，运用北京和东京两市居民的生活时间分配调查资料，对北京和东京两市居民的生活时间分配以及变动趋势进行了比较研究，反映了两市居民的生活方式的差异及其变化，探讨了形成这些差异和变化的主要原因。     

The power of the modified Wilcoxon rank-sum test for the one-sided alternative

When testing hypotheses in two-sample problems, the Wilcoxon rank-sum test is often used to test the location parameter, and this test has been discussed by many authors over the years. One modification of the Wilcoxon rank-sum test was proposed by Tamura [On a modification of certain rank tests. Ann Math Stat. 1963;34:1101–1103]. Deriving the exact critical value of the statistic is difficult when the sample sizes are increased. The normal approximation, the Edgeworth expansion, the saddlepoint approximation, and the permutation test were used to evaluate the upper tail probability for the modified Wilcoxon rank-sum test given finite sample sizes. The accuracy of various approximations to the probability of the modified Wilcoxon statistic was investigated. Simulations were used to investigate the power of the modified Wilcoxon rank-sum test for the one-sided alternative with various population distributions for small sample sizes. The method was illustrated by the analysis of real data.     

Asymptotic properties of the maximum smoothed partial likelihood estimator in the change-plane Cox model

The change-plane Cox model is a popular tool for the subgroup analysis of survival data. Despite the rich literature on this model, there has been limited investigation into the asymptotic properties of the estimators of the finite-dimensional parameter. Particularly, the convergence rate, not to mention the asymptotic distribution, has not been fully characterized for the general model where classification is based on multiple covariates. To bridge this theoretical gap, this study proposes a maximum smoothed partial likelihood estimator and establishes the following asymptotic properties. First, it shows that the convergence rate for the classification parameter can be arbitrarily close to $n^{-1}$ up to a logarithmic factor under a certain condition on covariates and the choice of tuning parameter. Given this convergence rate result, it also establishes the asymptotic normality for the regression parameter.