Nonparametric covariate adjustment for receiver operating characteristic curves

The accuracy of a diagnostic test is typically characterized using the receiver operating characteristic (ROC) curve. Summarizing indexes such as the area under the ROC curve (AUC) are used to compare different tests as well as to measure the difference between two populations. Often additional information is available on some of the covariates which are known to influence the accuracy of such measures. The authors propose nonparametric methods for covariate adjustment of the AUC. Models with normal errors and possibly non‐normal errors are discussed and analyzed separately. Nonparametric regression is used for estimating mean and variance functions in both scenarios. In the model that relaxes the assumption of normality, the authors propose a covariate‐adjusted Mann–Whitney estimator for AUC estimation which effectively uses available data to construct working samples at any covariate value of interest and is computationally efficient for implementation. This provides a generalization of the Mann–Whitney approach for comparing two populations by taking covariate effects into account. The authors derive asymptotic properties for the AUC estimators in both settings, including asymptotic normality, optimal strong uniform convergence rates and mean squared error (MSE) consistency. The MSE of the AUC estimators was also assessed in smaller samples by simulation. Data from an agricultural study were used to illustrate the methods of analysis. The Canadian Journal of Statistics 38:27–46; 2010 © 2009 Statistical Society of Canada     

Nonparametric M-regression with free knot splines

Many problems of practical interest can be formulated as the nonparametric estimation of a certain function such as a regression function, logistic or other generalized regression function, density function, conditional density function, hazard function, or conditional hazard function. Extended linear modeling provides a convenient theoretical framework for using polynomial splines and their selected tensor products in such function estimation problems and especially for obtaining rates of convergence of the resulting estimates in a unified manner. For a long time the theoretical results were restricted to fixed knot splines and to log-likelihood functions that were twice continuously differentiable. Recently, Stone and Huang extended the theory to handle free knot splines. In the present paper, the theory is further extended to handle contexts in which the log-likelihood function may not be differentiable. Specifically, we establish rates of convergence for estimation based on free knot splines in the context of nonparametric regression corresponding to M-estimates, which includes least absolute deviations (LAD) regression, quantile regression, and robust regression as special cases.     

Law of iterated logarithm and almost sure limit points for random sums

Let {X_n,n≥1} be a sequence of independent identically distributed (i.i.d) random variables with a common distribution function F. When F belongs to the domain of partial attraction of a Semi-Stable law with index ,0<<2, we give complete solution to the results of R. Vasudeva and G. Divanji [Law of iterated logarithm for random subsequences, Statist. Probab. Lett. 12 (1991) 189–194], where they obtained Chover’s form of the law of iterated logarithm for random subsequences. Further, we extended the situation in obtaining almost sure limit points for random subsequences.     

山西省区域经济差距变动趋势与原因探析——基于1978年-2009年山西省数据的实证分析

长期以来,山西省的区域经济差距显著。δ收敛检验表明,整体上看,1978年到2009年间山西省的区域经济差距呈现“趋异一趋同”的变化过程。然而,β收敛检验表明,在此期间山西省区域经济并没有发生绝对或相对β收敛。基于资本产出比分解法的增长核算分析表明,资本产出弹性是影响山西区域经济差距的重要因素。要素投入对地区差距的影响逐渐下降,而全要素生产率的影响逐渐上升。2003年到2009年,要素投入实际上是缩小区域差距的力量,山西省的区域差距完全来自于全要素生产率。山西省要继续缩小区域差距,必须从提高低收入地区的全要素生产率着手。     

论现代产业体系的构建

理解现代产业体系应该从三个方面出发：第一,现代产业体系是一个可持续发展、循环的产业体系;第二,现代产业体系是一个开放的、动态的创新型产业体系;第三,产业边界的模糊与产业间的融合是现代产业体系的根本特征。因此,现代产业体系的构建,必须在可持续发展的条件约束下,通过产业融合分化、解体和重组传统产业体系,并将其建设成一个开放式的创新型产业体系。最后,现代产业体系的构建还需要相应的支撑平台。     

3G业务融合创新的品牌策略研究

随着通信技术的进步,网络融合将给世界通信产业带来一系列的机遇和挑战。寻求一种有效的业务模式,顺利实现3G业务市场的推进则成为当前我国运营商战略转型关注的焦点。为此,通过设计3G业务融合创新的品牌架构模型,试图以品牌的建立、拓展和延伸三个阶段的营销策略的制定来探索2G业务向3G业务平滑演进的创新业务模式。     

会计国际化及我国应采取的对策

会计国际化是大势所趋,潮流所向,各国都要参与到这个协调过程中来。会计国际化过程体现了相关利益方经济利益的争夺,相应地就表现为一个政治过程。欧盟、澳大利亚、美国等国家先后宣布遵循或有意向接受国际财务报告准则很明确的体现了这一特征。探讨会计国际化的实质及发展趋势,并结合我国的实际,提出我国所面临的问题及应当采取的对策。     

中国绿色农业技术效率及其省际差异分析——基于1998—2012年的面板数据

基于1998—2012年面板数据,运用熵值法和DEA模型测算中国绿色农业产出和绿色农业技术效率,并分析其省际差异。研究表明,中国农业已经初具绿色转型的趋势,除东北地区外,其他地区绿色农业技术效率均上升;中国绿色农业技术效率有所提升,但整体水平仍然低下。东部、西部、东北、中部地区效率依次递减;全国省域间效率绝对差距没有缩小趋势,但相对差距明显缩小。东部、中部、西部和东北地区各地区内省域间绝对差距均没有缩小趋势,但东部、中部地区各地区内省域间相对差距存在缩小趋势,而西部、东北地区没有缩小趋势。全国2/3的省份绿色农业技术效率低下但处于增长态势;东北三省和内蒙古、宁夏、新疆陷入效率低下且呈下降态势的双重困境。     

媒介融合时代地方高校新闻教育的路向

新闻教育要服务于新闻实践,就必须不断调整教学目标和培养方向。当下,媒介形态、生态环境都促使各种媒介趋向融合,也对媒介从业者提出了新要求。新闻教育尤其是地方高校单一学科、单一技能的新闻人才培养模式已不能适应当前媒介融合的需要。地方高校新闻教育要紧跟媒介融合的趋势及新闻实践的变化,就必须打造以新媒体技术为基础的新闻实践教学平台,打破人才评价机制和引进机制,构建适合自身的学科架构,推行特色教育,积极探索融入地方经济社会发展的路径,培养具有融合理念、多种学科知识、多种媒介传播能力的高素质新闻人才。     

对《涉外民事关系法律适用法》的“两点论”评析

已于2011年4月1日正式施行的《中华人民共和国涉外民事关系法律适用法》从我国实际情况出发,改变了以往我国国际私法立法体系分散、法律规定不明确、相关制度规定不科学的状况,进一步完善了我国涉外民事关系法律适用制度。无论在立法体系,还是在编排体例、相关制度方面该法都体现了“两点论”的指导原则和影响,既充分借鉴了当今世界国际私法制度的先进理念,同时又从中国经济发展的实际情况出发,一定程度上体现了中国特色。