Frailty modelling approaches for semi-competing risks data

Lifetime Data Analysis - In the semi-competing risks situation where only a terminal event censors a non-terminal event, observed event times can be correlated. Recently, frailty models with an...     

基于微信平台艺术品拍卖的对策与建议

近年来,艺术品的微信拍卖逐渐成为人们热议的一个话题。2014年3月,“艺麦微拍”推出的朱新建的《美人图》以16.1万元的价格成交,创下微信平台拍卖艺术品的最高纪录。随着中国新媒体发展进一步呈现移动化、融合化和社会化加速的态势,微信拍卖的群体也在迅速扩大。一方面,微拍的现象越来越普遍,另一方面,作为一种新型的拍卖方式也饱受人们争议。由此探讨了艺术品微信拍卖的优势和存在的一些问题,在此基础之上结合实际情况提出了一些具体的对策与建议。     

中国由ICT渠道获取的国际R&D溢出门槛效应

采用2003-2012年中国除西藏外30个省市自治区的面板数据,考察信息通信技术渠道国际R & D溢出效应。运用面板单位根检验、协整检验、相关性分析、格兰杰因果检验、随机效应模型等计量方法,研究中国通过信息通信技术渠道获得的国际R & D溢出与当地全要素生产率之间的关系;建立Hansen非动态面板门槛模型,采用稳健标准差回归,检验各省份由信息通信技术渠道获得的国际R & D溢出门槛效应,并从产业转型升级和信息化建设角度分析存在门槛效应的原因。结果表明,中国大部分省份通过信息通信技术渠道获取的国际R & D溢出与全要素生产率有正相关关系;通过信息通信技术渠道获得的国际R & D溢出对当地技术进步的影响存在明显的地区差异和门槛效应。     

Statistical inference for homologous gene pairs between two circular genomes: a new circular–circular regression model

In this paper, we investigate the problem of determining the relationship, represented by similarity of the homologous gene configuration, between paired circular genomes using a regression analysis. We propose a new regression model for studying two circular genomes, where the Möbius transformation naturally arises and is taken as the link function, and propose the least circular distance estimation method, as an appropriate method for analyzing circular variables. The main utility of the new regression model is in identification of a new angular location of one of a homologous gene pair between two circular genomes, for various types of possible gene mutations, given that of the other gene. Furthermore, we demonstrate the utility of our new regression model for grouping of various genomes based on closeness of their relationship. Using angular locations of homologous genes from the five pairs of circular genomes (Horimoto et al. in Bioinformatics 14:789–802, 1998), the new model is compared with the existing models.     

一基于SEM的经济发展与社会发展关系——以济南市为例

利用济南市2001—2013年的数据,构建济南市经济与社会发展关系的结构方程模型(SEM),考量经济发展的4个潜变量(经济水平、经济结构、经济增速、经济物耗)与社会发展的4个潜变量(居民的生活质量、社会稳定、人口素质、生态环境)间的相互影响,结果表明,居民生活质量正相关于人口素质和经济水平,人口素质正相关于经济水平;居民生活质量作用于社会稳定,而社会稳定是生活质量的固有要求;生态环境负相关于经济增速和经济物耗。     

基于改进突变级数法的农产品物流产业评估模型研究

对农产品物流产业发展水平进行客观、准确的分析与评估,可为政府部门优化与调整产业发展、合理制定产业规划提供科学依据。运用突变级数法与离差最大化法构建农产品物流产业评估模型,并选取广东和山东两省20102014年相关数据对构建的评估模型进行实例分析。结果表明：广东省农产品物流产业发展的优势主要体现在信息化水平与经济基础两方面,基础设施建设则是当前制约其产业发展的关键因素;而庞大的产业规模是现阶段支撑山东省农产品物流产业发展的重要力量。改进的突变级数评估模型既克服了主观赋权的局限,又不失科学性和合理性,计算简单,具有重要实用价值。     

基于G1连续的圆弧与B样条分段区间确定及重构方法

在逆向工程中,截面曲线重构质量的高低决定了能否更好地反映物体的初始设计意图。高精度分段点的提取则 是提高重构质量的关键。针对圆弧与B样条曲线重构过程中,无法确定分段点所在区间问题,提出了圆弧与B样条线 性化处理方法,并结合基于数理统计原理的分段点区间确定办法和基于黄金分割法的重构方法,提取了圆弧与B样条间 的高精度分段点。实例证明该方法能在现存数据之间搜寻精度更高的分段点。该方法有效地解决了圆弧与B样条高精 度分段点提取问题。     

A Necessary Condition for the Strong Oracle Property

A problem of using a non‐convex penalty for sparse regression is that there are multiple local minima of the penalized sum of squared residuals, and it is not known which one is a good estimator. The aim of this paper is to give a guide to design a non‐convex penalty that has the strong oracle property. Here, the strong oracle property means that the oracle estimator is the unique local minimum of the objective function. We summarize three definitions of the oracle property – the global, weak and strong oracle properties. Then, we give sufficient conditions for the weak oracle property, which means that the oracle estimator becomes a local minimum. We give an example of non‐convex penalties that possess the weak oracle property but not the strong oracle property. Finally, we give a necessary condition for the strong oracle property.     

A nonparametric hypothesis test for heteroscedasticity

In this paper, a hypothesis test for heteroscedasticity is proposed in a nonparametric regression model. The test statistic, which uses the residuals from a nonparametric fit of the mean function, is based on an adaptation of the well-known Levene's test. Using the recent theory for analysis of variance when the number of factor levels goes to infinity, the asymptotic distribution of the test statistic is established under the null hypothesis of homocedasticity and under local alternatives. Simulations suggest that the proposed test performs well in several situations, especially when the variance is a nonlinear function of the predictor.     

中国城市化进程效率估算及影响因素分析

本文基于2008—2012年中国285个地级市的数据,运用双边随机前沿模型测算了中国城市化进程的前沿水平以及实际水平相对前沿水平的偏离程度。结果发现,下偏效应大于上偏效应,即中国城市化进程整体表现为滞后,并且发现投资作用和政府作用在影响城市化进程中的表现为负向,另外城市化进程也表现出地区间的不平衡。最后根据本文的发现,提出相应的建议。