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作者：Song, Qifan; Liang, Faming
作者单位：Purdue University System; Purdue University; State University System of Florida; University of Florida
摘要：During the past decade, penalized likelihood methods have been widely used in variable selection problems, where the penalty functions are typically symmetric about 0, continuous and nondecreasing in (0, infinity). We propose a new penalized likelihood method, reciprocal Lasso (or in short, rLasso), based on a new class of penalty functions that are decreasing in (0,infinity), discontinuous at 0, and converge to infinity when the coefficients approach zero. The new penalty functions give nearl...
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作者：Cao, Hongyuan; Churpek, Mathew M.; Zeng, Donglin; Fine, Jason P.
作者单位：University of Missouri System; University of Missouri Columbia; University of Chicago; University of Chicago; University of North Carolina; University of North Carolina Chapel Hill
摘要：Regression analysis of censored failure observations via the proportional hazards model permits time-varying covariates that are observed at death times. In practice, such longitudinal covariates are typically sparse and only measured at infrequent and irregularly spaced follow-up times. Full likelihood analyses of joint models for longitudinal and survival data impose stringent modeling assumptions that are difficult to verify in practice and that are complicated both inferentially and comput...
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作者：Fan, Jianqing; Tong, Xin; Zeng, Yao
作者单位：Princeton University; Capital University of Economics & Business; University of Southern California; Harvard University
摘要：When people in a society want to make inference about some parameter, each person may want to use data collected by other people. Information (data) exchange in social networks is usually costly, so to make reliable statistical decisions, people need to weigh the benefits and costs of information acquisition. Conflicts of interests and coordination problems will arise in the process. Classical statistics does not consider people's incentives and interactions in the data-collection process. To ...
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作者：Ma, Shujie; Song, Peter X. -K.
作者单位：University of California System; University of California Riverside; University of Michigan System; University of Michigan
摘要：It has been a long history of using interactions in regression analysis to investigate alterations in covariate-effects on response variables. In this article, we aim to address two kinds of new challenges arising from the inclusion of such high-order effects in the regression model for complex data. The first kind concerns a situation where interaction effects of individual covariates are weak but those of combined covariates are strong, and the other kind pertains to the presence of nonlinea...
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作者：Wikle, Christopher K.; Holan, Scott H.
作者单位：University of Missouri System; University of Missouri Columbia
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作者：Heaton, Matthew J.; Sain, Stephan R.; Monaghan, Andrew J.; Wilhelmi, Olga V.; Hayden, Mary H.
作者单位：Brigham Young University; National Center Atmospheric Research (NCAR) - USA
摘要：We analyze an incomplete marked point pattern of heat-related 911 calls between the years 2006-2010 in Houston, TX, to primarily investigate conditions that are associated with increased vulnerability to heat-related morbidity and, secondarily, build a statistical model that can be used as a public health tool to predict the volume of 911 calls given a time frame and heat exposure. We model the calls as arising from a nonhomogenous Cox process with unknown intensity measure. By using the kerne...
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作者：Zhu, Jian; Raghunathan, Trivellore E.
作者单位：University of Michigan System; University of Michigan
摘要：A sequential regression or chained equations imputation approach uses a Gibbs sampling-type iterative algorithm that imputes the missing values using a sequence of conditional regression models. It is a flexible approach for handling different types of variables and complex data structures. Many simulation studies have shown that the multiple imputation inferences based on this procedure have desirable repeated sampling properties. However, a theoretical weakness of this approach is that the s...
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作者：Ma, We; Hu, Feifang; Zhang, Lixin
作者单位：University of Virginia; George Washington University; Zhejiang University
摘要：Covariate-adaptive designs are often implemented to balance important covariates in clinical trials. However, the theoretical properties of conventional testing hypotheses are usually unknown under covariate-adaptive randomized clinical trials. In the literature, most studies are based on simulations. In this article, we provide theoretical foundation of hypothesis testing under covariate-adaptive designs based on linear models. We derive the asymptotic distributions of the test statistics of ...
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作者：Ke, Zheng Tracy; Fan, Jianqing; Wu, Yichao
作者单位：Princeton University; North Carolina State University
摘要：This article explores the homogeneity of coefficients in high-dimensional regression, which extends the sparsity concept and is more general and suitable for many applications. Homogeneity arises when regression coefficients corresponding to neighboring geographical regions or a similar cluster of covariates are expected to be approximately the same. Sparsity corresponds to a special case of homogeneity with a large cluster of known atom zero. In this article, we propose a new method called cl...
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作者：Leeb, Hannes
作者单位：University of Vienna
