Finite mixture of regression models for a stratified sample

Despite the popularity and importance, there is limited work on modelling data which come from complex survey design using finite mixture models. In this work, we explored the use of finite mixture regression models when the samples were drawn using a complex survey design. In particular, we considered modelling data collected based on stratified sampling design. We developed a new design-based inference where we integrated sampling weights in the complete-data log-likelihood function. The expectation–maximisation algorithm was developed accordingly. A simulation study was conducted to compare the new methodology with the usual finite mixture of a regression model. The comparison was done using bias-variance components of mean square error. Additionally, a simulation study was conducted to assess the ability of the Bayesian information criterion to select the optimal number of components under the proposed modelling approach. The methodology was implemented on real data with good results.     

Robust nonparametric estimation with missing data

In this paper, under a nonparametric regression model, we introduce two families of robust procedures to estimate the regression function when missing data occur in the response. The first proposal is based on a local M$M$-functional applied to the conditional distribution function estimate adapted to the presence of missing data. The second proposal imputes the missing responses using the local M$M$-smoother based on the observed sample and then estimates the regression function with the completed sample. We show that the robust procedures considered are consistent and asymptotically normally distributed. A robust procedure to select the smoothing parameter is also discussed.     

区域知识资源配置结构和谐指数测度分析

通过分析知识资源配置结构和谐的内涵和构成,构建国家区域知识资源配置结构和谐指数测量的二阶段模型,以2000年至2007年我国31个省市的知识分布为研究对象,结合熵权TOPSIS和扩展的基尼系数方法,测量我国区域人力资本知识资源结构和谐指数、知识资源投入运行结构和谐指数、区域知识经济环境和谐指数和区域总体知识资源配置结构和谐指数,主要得出以下结论:人力资本知识资源结构较为和谐,指数变化幅度较小,但没有优化趋势;知识资源投入运行结构非常和谐,且愈趋优化;区域知识经济环境和谐指数相对最不和谐,区域间存在较大差异;区域总体知识资源配置结构较为和谐,但变化幅度较大,尚没有显著优化趋向。     

我国城镇居民家庭纯收入和生活消费支出的典型相关分析

文章介绍了两组随机变量相关性的一种统计分析方法———典型相关分析(canonicalcorrelationanalysis),然后利用这种方法,借助SAS软件研究了我国31个省市自治区城镇居民家庭纯收入与生活消费支出的相关关系。     

实现蔡氏电路族的两种新的规范电路

本文介绍了两种新的规范电路。导出了计算这两种规范电路参数的显式公式,还推广了两位学者的有关定理,使之也适用于新的规范电路。本文设计的规范电路表明,实现蔡氏电路族的规范电路不是唯一的。而其中改造的蔡氏电路也许是最好的一种。     

具有多元权值约束的鲁棒 LPM 积极投资组合

在用方差控制投资组合风险的同时,由于方差的对称性导致投资组合的收益也受到限制． 相比之下,下偏距 (lower partial moment: LPM) 由于具有只控制风险,而不限制收益的特点,在近年来倍受关注． 但在非正态假设下,LPM 无法获得良好的解析性质． 在对资产收益分布未知的假设下,通过使用最坏情形下的LPM来度量投资组合的损失,提出了具有多元权值约束的鲁棒积极投资组合问题,并获得了具有m( m=0,1,2) -阶 LPM 约束的鲁棒积极投资组合问题的解析解． 通过分析解的性质和比较问题的有效前沿,得到了许多有趣的和新颖的结果． 数值结果比较表明,鲁棒LPM模型比经典的均值－方差模型具有许多更好的性能．     

基于可变区间权重的中期用电量半参数预测模型

由于数据变化规律的多样性,中期电力负荷的波动有着不同于短期、长期负荷的特点。基于电力系统复杂性的研究视角,重点讨论了中期负荷预测过程中模型的不确定性、参数的时变特性以及负荷波动的周期性规律。根据中期负荷的数据特性,建立了基于非参数修匀的半参数模型,定义了函数区间的划分粒度以及模型权重的求解方法,提出了基于可变区间权重的动态预测方法,给出了基于经验模态分解和波动能量分析的噪声序列提取、检验方法。试验研究结果表明,气候因素对用电消耗的影响最大,经济因素次之;从选取的指标来看,不同时期的影响因素对于模型的解释能力是时变的;所提方法能够对电力负荷进行精确的多粒度、多维度分析,进而掌握其局部变化规律,可有效用于电力系统中期负荷预测。     

Reducing differences between profiles of weights: A “peer-restricted” cross-efficiency evaluation

This paper deals with the selection of the profiles of weights to be used in cross-efficiency evaluations. In an attempt to prevent unrealistic weighting schemes, one of the issues of main interest that we address here is that of the zero weights, since their use implies that some of the variables considered are excluded from the assessments to be made. In the calculation of cross-efficiency scores, we propose to ignore the profiles of weights of the DMUs that cannot make a choice of non-zero weights among their alternate optima. The different units are therefore assessed in a peer-evaluation that does not consider the profiles of weights of some inefficient DMUs. This approach is referred to as “peer-restricted” cross-efficiency evaluation. Aside from avoiding zero weights, the choice of weights that we make also seeks to reduce the differences between the weights profiles selected as much as possible. Thus, in the “peer-restricted” cross-efficiency evaluation in the present paper we also try to avoid that the different DMUs attach very different weights to the same variable. Finally, we extend this approach to derive a common set of weights by exploiting the idea of similarity between profiles of weights.     

民国上海度政始末

度量衡与天文立法、音律三者是我国中华古老文明的基础,是民众从事经济活动的重要凭借,是百物制度的标准,也是国家政权统一的象征与经济社会发展的保障. 民国时期,地处东部沿海的上海市,开始了全市度量衡标准的划一与度量衡新器的推行工作,最终完成了划一工作,促进了民国时期上海经济社会的发展.     

农业纵向分工：服务外包的影响因子测度——基于专家问卷的定量评估

将农户的农业生产经营分为9个环节,基于农业生产环节交易特性与农户行为能力两个层面,测度农业生产环节进行服务外包的影响因子。农业生产环节的交易特性细分为专用性、规模性与风险性3个维度,农户行为能力则由排他能力、处置能力和交易能力3个维度表达。基于专家问卷,借助模糊数学和层次分析方法,对影响因子的权重进行定量评估。结果显示,同样的影响因素在不同的农业生产环节中表现出不同的特征,不同的影响因素在同一个农业生产环节中表现出的特征也有所差异。