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作者：Antoniano-Villalobos, Isadora; Wade, Sara; Walker, Stephen G.
作者单位：Bocconi University; University of Cambridge; University of Texas System; University of Texas Austin; University of Texas System; University of Texas Austin
摘要：Hippocampal volume is one of the best established biomarkers for Alzheimer's disease. However, for appropriate use in clinical trials research, the evolution of hippocampal volume needs to be well understood. Recent theoretical models propose a sigmoidal pattern for its evolution. To support this theory, the use of Bayesian nonparametric regression mixture models seems particularly suitable due to the flexibility that models of this type can achieve and the unsatisfactory predictive properties...
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作者：Li, Ruosha; Cheng, Yu; Fine, Jason P.
作者单位：Pennsylvania Commonwealth System of Higher Education (PCSHE); University of Pittsburgh; Pennsylvania Commonwealth System of Higher Education (PCSHE); University of Pittsburgh; Pennsylvania Commonwealth System of Higher Education (PCSHE); University of Pittsburgh; University of North Carolina; University of North Carolina Chapel Hill
摘要：It is often important to study the association between two continuous variables. In this work, we propose a novel regression framework for assessing conditional associations on quantiles. We develop general methodology which permits covariate effects on both the marginal quantile models for the two variables and their quantile associations. The proposed quantile copula models have straightforward interpretation, facilitating a comprehensive view of association structure which is much richer th...
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作者：Zhou, Yong-Dao; Xu, Hongquan
作者单位：Sichuan University; University of California System; University of California Los Angeles
摘要：Fractional factorial designs are widely used in various scientific investigations and industrial applications. Level permutation of factors could alter their geometrical structures and statistical properties. This article studies space-filling properties of fractional factorial designs under two commonly used space-filling measures, discrepancy and maximin distance. When all possible level permutations are considered, the average discrepancy is expressed as a linear combination of generalized ...
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作者：Lei, Jing
作者单位：Carnegie Mellon University
摘要：This article studies global testing of the slope function in functional linear regression models. A major challenge in functional global testing is to choose the dimension of projection when approximating the functional regression model by a finite dimensional multivariate linear regression model. We develop a new method that simultaneously tests the slope vectors in a sequence of functional principal components regression models. The sequence of models being tested is determined by the sample...
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作者：Lijoi, Antonio; Nipoti, Bernardo
作者单位：University of Pavia; University of Turin; Collegio Carlo Alberto
摘要：Mixture models for hazard rate functions are widely used tools for addressing the statistical analysis of survival data subject to a censoring mechanism. The present article introduced a new class of vectors of random hazard rate functions that are expressed as kernel mixtures of dependent completely random measures. This leads to define dependent nonparametric prior processes that are suitably tailored to draw inferences in the presence of heterogenous observations. Besides its flexibility, a...
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作者：Huang, Hui; Ma, Xiamei; Waagepetersen, Rasmus; Holford, Theodore R.; Wang, Rong; Risch, Harvey; Mueller, Lloyd; Guan, Yongtao
作者单位：University of Miami; Yale University; Aalborg University
摘要：We propose a novel two-step procedure to combine epidemiological data obtained from diverse sources with the aim to quantify risk factors affecting the probability that an individual develops certain disease such as cancer. In the first step, we derive all possible unbiased estimating functions based on a group of cases and a group of controls each time. In the second step, we combine these estimating functions efficiently to make full use of the information contained in data. Our approach is ...
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作者：Graham, Daniel J.; McCoy, Emma J.; Stephens, David A.
作者单位：Imperial College London; Imperial College London; McGill University
摘要：Road network capacity expansions are frequently proposed as solutions to urban traffic congestion but are controversial because it is thought that they can directly induce growth in traffic volumes. This article quantifies causal effects of road network capacity expansions on aggregate urban traffic volume and density in U.S. cities using a mixed model propensity score (PS) estimator. The motivation for this approach is that we seek to estimate a dose-response relationship between capacity and...
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作者：Tian, Lu; Alizadeh, Ash A.; Gentles, Andrew J.; Tibshirani, Robert
作者单位：Stanford University; Stanford University; Stanford University; Stanford University
摘要：We consider a setting in which we have a treatment and a potentially large number of covariates for a set of observations, and wish to model their relationship with an outcome of interest. We propose a simple method for modeling interactions between the treatment and covariates. The idea is to modify the covariate in a simple way, and then fit a standard model using the modified covariates and no main effects. We show that coupled with an efficiency augmentation procedure, this method produces...
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作者：Cai, T. Tony; Low, Mark; Ma, Zongming
作者单位：University of Pennsylvania
摘要：This article proposes a new formulation for the construction of adaptive confidence bands (CBs) in nonparametric function estimation problems. CBs, which have size that adapts to the smoothness of the function while guaranteeing that both the relative excess mass of the function lying outside the band and the measure of the set of points where the function lies outside the band are small. It is shown that the bands adapt over a maximum range of Lipschitz classes. The adaptive CB can be easily ...
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作者：Liang, Faming; Cheng, Yichen; Lin, Guang
作者单位：Texas A&M University System; Texas A&M University College Station; United States Department of Energy (DOE); Pacific Northwest National Laboratory
摘要：Simulated annealing has been widely used in the solution of optimization problems. As known by many researchers, the global optima cannot be guaranteed to be located by simulated annealing unless a logarithmic cooling schedule is used. However, the logarithmic cooling schedule is so slow that no one can afford to use this much CPU time. This article proposes a new stochastic optimization algorithm, the so-called simulated stochastic approximation annealing algorithm, which is a combination of ...
