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作者：Jin, Ick Hoon; Liu, Suyu; Thall, Peter F.; Yuan, Ying
作者单位：University of Texas System; UTMD Anderson Cancer Center
摘要：A practical impediment in adaptive clinical trials is that outcomes must be observed soon enough to apply decision rules to choose treatments for new patients. For example, if outcomes take up to six weeks to evaluate and the accrual rate is one patient per week, on average three new patients will be accrued while waiting to evaluate the outcomes of the previous three patients. The question is how to treat the new patients. This logistical problem persists throughout the trial. Various ad hoc ...
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作者：Xiao, Yongling; Abrahamowicz, Michal; Moodie, Erica E. M.; Weber, Rainer; Young, James
作者单位：McGill University; University of Zurich; University Zurich Hospital; University of Basel; Swiss School of Public Health (SSPH+)
摘要：The association between antiretroviral treatment and cardiovascular disease (CVD) risk in HIV-positive persons has been the subject of much debate since the Data collection on Adverse events of Anti-HIV Drugs (D: A: D) study reported that recent use of two antiretroviral drugs, abacavir (ABC) and didanosine (DDI), was associated with increased risk. We focus on the potential impact of DDI use, as this drug has not been as studied intensively as ABC. We propose a flexible marginal structural Co...
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作者：Fronczyk, Kassandra; Kottas, Athanasios
作者单位：University of California System; University of California Santa Cruz
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作者：Patilea, Valentin; Raissi, Hamdi
作者单位：Ecole Nationale de la Statistique et de l'Analyse de l'Information (ENSAI)
摘要：This article considers the volatility modeling for autoregressive univariate time series. A benchmark approach is the stationary autoregressive conditional heteroscedasticity (ARCH) model of Engle. Motivated by real data evidence, processes with nonconstant unconditional variance and ARCH effects have been recently introduced. We take into account this type of nonstationarity in variance and propose simple testing procedures for ARCH effects. Adaptive McLeod and Li's portmanteau and ARCH-LM te...
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作者：Xiao, Luo; Thurston, Sally W.; Ruppert, David; Love, Tanzy M. T.; Davidson, Philip W.
作者单位：Johns Hopkins University; University of Rochester; Cornell University; Cornell University; University of Rochester; University of Rochester; University of Rochester
摘要：The Seychelles Child Development Study (SCDS) examines the effects of prenatal exposure to methylmercury on the functioning of the central nervous system. The SCDS data include 20 outcomes measured on 9-year-old children that can be classified broadly in four outcome classes or domains: cognition, memory, motor, and social behavior. Previous analyses and scientific theory suggest that these outcomes may belong to more than one of these domains, rather than only a single domain as is frequently...
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作者：Jones, Bradley; Majumdar, Dibyen
作者单位：University of Antwerp; SAS Institute Inc; University of Illinois System; University of Illinois Chicago; University of Illinois Chicago Hospital
摘要：We consider screening experiments where an investigator wishes to study many factors using fewer observations. Our focus is on experiments with two-level factors and a main effects model with intercept. Since the number of parameters is larger than the number of observations, traditional methods of inference and design are unavailable. In 1959, Box suggested the use of supersaturated designs and in 1962, Booth and Cox introduced measures for efficiency of these designs including E(s(2)), which...
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作者：Zhou, Qing
作者单位：University of California System; University of California Los Angeles
摘要：Regularized linear regression under the l(1) penalty, such as the Lasso, has been shown to be effective in variable selection and sparse modeling. The sampling distribution of an l(1)-penalized estimator (beta) over cap is hard to determine as the estimator is defined by an optimization problem that in general can only be solved numerically and many of its components may be exactly zero. Let S be the subgradient of the (1) norm of the coefficient vector beta evaluated at (beta) over cap. We fi...
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作者：Luo, Shan; Chen, Zehua
作者单位：Shanghai Jiao Tong University; National University of Singapore
摘要：In this article, we propose a method called sequential Lasso (SLasso) for feature selection in sparse high-dimensional linear models. The SLasso selects features by sequentially solving partially penalized least squares problems where the features selected in earlier steps are not penalized. The SLasso uses extended BIC (EBIC) as the stopping rule. The procedure stops when EBIC reaches a minimum. The asymptotic properties of SLasso are considered when the dimension of the feature space is ultr...
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作者：Rosenbaum, Paul R.
作者单位：University of Pennsylvania
摘要：In a nonrandomized or observational study, a weak association between receipt of the treatment and an outcome may be explained not as effects caused by the treatment but rather by a small bias in the assignment of individuals to treatment or control; however, a strong association may be explained as noncausal only by a large bias. The strength of the association between treatment and outcome is not uniform across the data from a study, and this motivates giving greater weight where the associa...
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作者：Wang, Bo; Shi, Jian Qing
作者单位：University of Leicester; Newcastle University - UK
摘要：In this article, we propose a generalized Gaussian process concurrent regression model for functional data, where the functional response variable has a binomial, Poisson, or other non-Gaussian distribution from an exponential family, while the covariates are mixed functional and scalar variables. The proposed model offers a nonparametric generalized concurrent regression method for functional data with multidimensional covariates, and provides a natural framework on modeling common mean struc...
