Covariate Selection for the Semiparametric Additive Risk Model

Abstract.  This paper considers covariate selection for the additive hazards model. This model is particularly simple to study theoretically and its practical implementation has several major advantages to the similar methodology for the proportional hazards model. One complication compared with the proportional model is, however, that there is no simple likelihood to work with. We here study a least squares criterion with desirable properties and show how this criterion can be interpreted as a prediction error. Given this criterion, we define ridge and Lasso estimators as well as an adaptive Lasso and study their large sample properties for the situation where the number of covariates p is smaller than the number of observations. We also show that the adaptive Lasso has the oracle property. In many practical situations, it is more relevant to tackle the situation with large p compared with the number of observations. We do this by studying the properties of the so-called Dantzig selector in the setting of the additive risk model. Specifically, we establish a bound on how close the solution is to a true sparse signal in the case where the number of covariates is large. In a simulation study, we also compare the Dantzig and adaptive Lasso for a moderate to small number of covariates. The methods are applied to a breast cancer data set with gene expression recordings and to the primary biliary cirrhosis clinical data.     

严羽和戴复古身世行迹诸问题考——对《严羽评传》的几点商榷性意见

严羽和戴复古订交的时间在绍定五年 (12 32 )而非嘉定十四年 (12 2 1) ;严羽避乱返乡时间在绍定四年而非元年 ;严羽的《平寇颂》写于端平元年 (12 34 )五月之后而非绍定三年间 ;戴复古布衣一生 ,并未任过邵武军学教授     

李贺诗的"内热"探源

李贺诗外表"冷艳"实则"内热","冷艳"是其外在表现,而内中却蕴含着诗人矫世的热情、人生的眷恋、个性的张扬.这些构成了李贺诗创作的内驱力.文章从蹭蹬不遇的苦闷、对世事的忧虑和愤概、对生死问题的困惑三个方面出发,揭示了李贺创作的心理背景和内在依据.     

Distribution and density functions of the feasible generalized ridge regression estimator

In this paper, we derive the distribution and density functions of the feasible generalized ridge regression (GRR) estimator. It is shown that when the absolute value of a regression coefficient is close to zero, the distribution of the feasible GRR estimator is bimodal and has thinner tails than that of the OLS estimator.     

On the analysis of multivariate repeated measures designs

The relationship between the mixed-model analysis and multivariate approach to a repeated measures design with multiple responses is presented. It is shown that by taking the trace of the appropriate submatrix of the hypothesis (error) sums of squares and crossproducts (SSCP) matrix obtained from the multivariate approach, one can get the hypothesis (error) SSCP matrix for the mixed-model analysis. Thus, when analyzing data from a multivariate repeated measures design, it is advantageous to use the multivariate approach because the result of the mixed-model analysis can also be obtained without additional computation.     

元好问《续夷坚志》与金末元初的文坛

元好问《续夷坚志》 ,以“小说存史” ,记叙文人行踪的故事 ,保留了金代文人交往的重要资料 ,具有较高的文学价值和文学史料价值     

试论合同解除

本文作者通过考察大陆法系及英美法系关于合同解除的相关规定和司法实践,对这一概念进行界定。并在分析德国新立法动向的基础上,对两大法系中合同解除制度的构成作分类比较。尔后对合同解约权的行使条件进行论述并进一步探讨了相关国际公约的规定。最后作者在小结该制度的基础上对某些问题及发展动向提出了一些见解。     

"唐山流寓话巢痕"--杨若萍《台湾与大陆文学关系简史》评述

简要评述杨若萍博士<台湾与大陆文学关系简史>一书,指出:杨著以详实的史料勾勒两岸文学发展的互动关系,并将大陆文学看作是台湾文学的母体,以批驳强行将两岸文学分割开来的"本土文学论"者的错误论调,其立论之平实,论证之谨严,足为细辨"巢痕"之力作,也使我们这些置身岛外的人们对台湾文学的发展与走向有了相当清晰的了解.     

国际碳市场价格驱动力研究——以欧盟排放交易体系为例

探索碳市场价格驱动力是能源经济领域关注的焦点问题之一。基于欧盟排放交易体系（EU ETS）碳期货价格,综合运用结构性断点检验、协整技术和岭回归方法分析碳市场价格驱动因素和驱动模式。结果表明:2007年巴厘行动计划、2008年全球金融危机和2011年欧债危机,均对碳市场价格走势产生了显著影响,导致了碳市场价格发生结构性变化;碳市场价格与能源价格、工业生产、气温条件等因素间存在协整关系;自2009年10月以来,碳市场价格观测值低于均衡值,未来碳市场价格仍将倾向于贬值。     

远古湖湘水文化的时空透视与洞庭湖船文化溯源

洞庭湖远在华夏文明伊始之前即为汪洋大泽。居住在水边的湖湘远古各族先民们所创造的灿烂水文化在中国乃至世界的文明史上占有重要的地位。湖湘文明孕育出了洞庭湖船文化 ,它是世界船文化和中国龙舟文化的发祥地之一。“轩辕作舟”之说不可靠。它同视洞庭湖地区为蒙昧的“南蛮”地区一样 ,都是受了所谓中原正统文化观念的局囿。湖湘远古居民的灵感、智慧、思维和创造力 ,对中华文化构成了独特的历史贡献