Feasible algorithm for linear mixed model for massive data

This article studies computation problem in the context of estimating parameters of linear mixed model for massive data. Our algorithms combine the factored spectrally transformed linear mixed model method with a sequential singular value decomposition calculation algorithm. This combination solves the operation limitation of the method and also makes this algorithm feasible to big dataset, especially when the data has a tall and thin design matrix. Our simulation studies show that our algorithms make the calculation of linear mixed model feasible for massive data on ordinary desktop and have same estimating accuracy with the method based on the whole data.     

职业特征对中国城镇就业人员收入差别的影响(英文)

职业是决定就业人员劳动收入,继而影响居民收入差距程度的重要变量。本文利用国家统计局2005年全国1％人口抽样调查数据中的子样本,对职业与收入差别之间的关系做了经验分析,结果发现职业间收入差距可以解释城镇就业人员收入总体差距的12-17％。造成这种差别的主要原因有二：一是由于各职业对就业人员人力资本上的要求有差异,从而导致了职业间劳动要素报酬上的差异;二是劳动力市场、地区分割所带来的不同职业问人员自由流动的障碍,造成了这种收入差别。前一种原因强调了人力资本的作用,这应当是市场化改革的积极成效;而后一种原因反映的却是现阶段的市场化改革还不彻底。因此,为了缩小职业间不合理的收入差距,我们还应进一步深化改革,尽可能地排除由于市场、地区分割造成的不同职业间人员自由流动的障碍。     

基于Benders分解算法的跨区互联电力系统协调规划模型

研究跨区互联电力系统的协调规划,对于提高投资效率实现更大范围的资源配置具有较强现实意义。本文首先描述多区域电力系统扩张规划问题,并建立多区域扩张规划模型,旨在寻求最优的扩容方案,以最小投入来满足多区域电力系统负荷增长需求;其次,采用Benders分解算法将多区域扩张规划问题分解为一个规划主问题和一个运行子问题,通过主子问题之间的迭代求解,获得最终的最优解;最后,对某个典型的包含7个区域的多区域电力系统进行模拟仿真,验证了本文所构建模型及算法的有效性。     

Restricted maximum likelihood estimation of joint mean‐covariance models

The class of joint mean‐covariance models uses the modified Cholesky decomposition of the within subject covariance matrix in order to arrive to an unconstrained, statistically meaningful reparameterisation. The new parameterisation of the covariance matrix has two sets of parameters that separately describe the variances and correlations. Thus, with the mean or regression parameters, these models have three sets of distinct parameters. In order to alleviate the problem of inefficient estimation and downward bias in the variance estimates, inherent in the maximum likelihood estimation procedure, the usual REML estimation procedure adjusts for the degrees of freedom lost due to the estimation of the mean parameters. Because of the parameterisation of the joint mean covariance models, it is possible to adapt the usual REML procedure in order to estimate the variance (correlation) parameters by taking into account the degrees of freedom lost by the estimation of both the mean and correlation (variance) parameters. To this end, here we propose adjustments to the estimation procedures based on the modified and adjusted profile likelihoods. The methods are illustrated by an application to a real data set and simulation studies. The Canadian Journal of Statistics 40: 225–242; 2012 © 2012 Statistical Society of Canada     

Decomposing the complete graph into dodecahedra

We prove that the complete graph K_v can be decomposed into dodecahedra if and only if v≡ 1, 16, 25 or 40 (mod 60), v≠16.     

农村居民消费不平等的微观结构分析

提出了个体微观数据基尼系数的组群、要素统一分解式,并利用该分解式考察消费结构、区域结构和收入不平等对农村居民消费不平等的影响.采用了2009年福建省农村居民生活状况调查数据进行分析,得出结论:食品、衣着类消费的增长可以降低农村居民的消费不平等,其中谷物、薯类、食用油、蔬菜及制品、肉禽蛋奶及制品的消费增长对消费公平性的提高产生积极的作用;组内不平等在总体消费不平等中占80％以上,消费差异主要表现为内部的差异;农村居民的消费不平等受收入不平等影响显著.     

陕西省二氧化碳库兹涅茨曲线的形状、拐点与影响因素

以中国首批低碳试点地区——陕西省为研究对象,利用1978—2010年的时间序列数据,对人均二氧化碳排放的库兹涅茨曲线进行了经验估计,发现曲线形状为N型,两个拐点分别在人均GDP为3 370.31元和4 070.06元处。对影响人均二氧化碳排放的因素进行研究,利用迪式分解法进行短期分析,发现经济收入和能源消耗强度对人均二氧化碳的排放影响较大,而能源结构的影响很小;利用协整方程进行长期分析,结果表明,能源消耗强度、能源结构和第二产业结构对人均二氧化碳排放量的影响作用都比较大,其中最大的是能源结构。     

Marriage,Marital History,and Black – White Wealth Differentials Among Older Women

This study investigated the impact of union history and marital transitions on wealth inequality between older Black and White women (N = 7,026). Cohort data from the Health and Retirement Study show large and increasing Black – White differences in wealth. Marital and relationship histories are associated with the wealth accumulation process among older women. Women who married and stay married accumulated levels of wealth that exceeded those of other women with disrupted family lives. The marriage – wealth nexus is sensitive to a woman's position in the wealth distribution. Quantile regression results revealed that racial differences in total wealth holdings between Black and White women exist throughout the wealth distribution, whereas the relationship between current union history and wealth differentials is significant at the lower tail and middle of the distribution. Decomposition analyses highlighted the nontrivial role of racial disparities in marital histories in accounting for the racial wealth gap. As members of the baby boom generation enter their retirement years, it will be more important than ever to monitor the wealth accumulation process among older single and racial/ethnic minority women.     

The Level and Age Pattern of Mortality in Bandafassi (Eastern Senegal): Results From a Small-Scale and Intensive Multi-Round Survey

The data collected in the Bandafassi demographic study in Eastern Senegal, a small-scale intensive and experimental follow-up survey of a population of about 7,000 in 1983, were analysed to derive an estimated life table. The use of multi-round surveys, combined with anthropological methods to estimate ages and collect genealogies, has resulted in unusually reliable data. Taking into account the uncertainty of the estimates due to the small size of the population, mortality was high, with life-expectancy at birth close to 31 years; a pattern of infant and child mortality close to that observed in other rural areas of Senegal, with a very high level or mortality between ages six months and three years; a seasonal pattern in child mortality with two high-risk periods, the rainy season and the end of the dry season; an adult mortality pattern similar to that described in model life tables for developed countries; no significant difference by sex or ethnic group. The Bandafassi population study and a few similar studies suggest that one possible way to improve demographic estimates in countries where vital registration systems are defective would be to set up a sample of population laboratories where intensive methods of data collection would continue for extended periods.     

Inter‐industry Inequality: An Important Source of the Urban Income Gap—Regression‐based Decomposition

基于回归方程的收入差距分解发现,1988年、1995年和2002年,行业间收入不平等对中国城镇居民收入差距的贡献越来越大,而且这主要是由一些收入迅速提高的垄断行业造成的。同时,区位、教育、所有制和职业类型以及是否有第二职业对收入差距的贡献也在提高,是否完全就业和年龄对收入差距的贡献明显下降。因此,缩小中国城镇收入差距,亟需打破劳动力市场进入壁垒和产品市场行业垄断。此外,减轻地区间的劳动力流动障碍、普遍提高劳动者的受教育水平等措施也将是未来政府缩小城镇收入差距的重要政策着力点。

关键词: 行业垄断?收入差距分解?夏普里值

Regression‐based decomposition of inter‐industry earnings differentials shows that in 1988, 1995 and 2002, inter‐industry earnings differentials made an increasing contribution to urban earnings inequality in China. The primary reason for the widening gap lay in monopoly industries. At the same time, geographical location, educational level, type of enterprise ownership, type of occupation and whether the individual had a second job also contributed to rising earnings inequality, while age and being fully employed made a decreasing contribution. Therefore, if China is to reduce the earnings gap it is imperative that we remove barriers to labor market entry and break down some monopoly industries in the product market. Additionally, reducing obstacles to the free movement of labor and improving workers' educational level should also be important elements of the government's strategy for reducing the urban income gap in future.