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作者：Bouman, Peter; Meng, Xiao-Li; Dignam, James; Dukic, Vanja
作者单位：Northwestern University; Harvard University; University of Chicago
摘要：In multicenter studies, one often needs to make inference about a population survival curve based on multiple, possibly heterogeneous survival data from individual centers. We investigate a flexible Bayesian method for estimating a population survival curve based on a semiparametric multiresolution hazard model that can incorporate covariates and account for center heterogeneity. The method yields a smooth estimate of the survival curve for multiple resolutions or time scales of interest. The ...
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作者：Fried, Roland; Einbeck, Jochen; Gather, Ursula
作者单位：Dortmund University of Technology; Durham University
摘要：We propose weighted repeated median filters and smoothers for robust nonparametric regression in general and for robust online signal extraction from time series in particular. The new methods allow us to remove outlying sequences and to preserve discontinuities (shifts) in the underlying regression function (the signal) in the presence of local linear trends. Suitable weighting of the observations according to their distances in the design space reduces the bias arising from nonlinearities an...
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作者：Lazar, Nicole A.
作者单位：University System of Georgia; University of Georgia
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作者：Cheung, Ying Kuen
作者单位：Columbia University
摘要：This article considers the problem of finding the maximum tolerated dose (MTD) of a drug in human trials. The MTD is defined as the maximum test dose with toxicity probability less than or equal to a target toxicity rate. We adopt the multiple test framework, with step-down tests used in an escalation stage and step-up tests used in a deescalation stage, to allow sequential dose assignments for ethical purposes. By formulating the estimation problem as a testing problem, the proposed procedure...
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作者：Guan, Yongtao; Loh, Ji Meng
作者单位：Yale University; Columbia University
摘要：When modeling inhomogeneous spatial point patterns, it is of interest to fit a parametric model for the first-order intensity function (FOIF) of the process in terms of some measured covariates. Estimates for the regression coefficients, say, can be obtained by maximizing a Poisson maximum likelihood criterion. Little work has been done on the asymptotic distribution of except in some special cases. In this article we show that is asymptotically normal for a general class of mixing processes. ...
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作者：Mandel, Micha; Gauthier, Susan A.; Guttmann, Charles R. G.; Weiner, Howard L.; Betensky, Rebecca A.
作者单位：Hebrew University of Jerusalem; Harvard University; Harvard Medical School; Harvard University Medical Affiliates; Brigham & Women's Hospital; Harvard University; Harvard University Medical Affiliates; Brigham & Women's Hospital; Harvard Medical School; Harvard University; Harvard University Medical Affiliates; Brigham & Women's Hospital; Harvard Medical School; Harvard University; Harvard Medical School
摘要：The expanded disability status scale (EDSS) is an ordinal score that measures progression in multiple sclerosis (MS). Progression is defined as reaching EDSS of a certain level (absolute progression) or increasing EDSS by one point (relative progression). Survival methods for time to progression are not adequate for such data because they do not exploit the EDSS level at the end of follow-up. Instead, we suggest a Markov transitional model applicable for repeated categorical or ordinal data. T...
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作者：Zhu, Hongtu; Zhang, Heping; Ibrahim, Joseph G.; Peterson, Bradley S.
作者单位：University of North Carolina; University of North Carolina Chapel Hill; Yale University; University of North Carolina; University of North Carolina Chapel Hill; Columbia University; New York State Psychiatry Institute
摘要：Diffusion tensor imaging has been widely used to reconstruct the structure and orientation of fibers in biological tissues, particularly in the white matter of the brain, because it can track the effective diffusion of water along those fibers. The raw diffusion-weighted images from which diffusion tensors are estimated, however, inherently contain noise. Noise in the images produces uncertainty in the estimation of the tensors (which are 3 x 3 positive-definite matrices) and of their derived ...
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作者：Zeng, Donglin; Lin, D. Y.
作者单位：University of North Carolina; University of North Carolina Chapel Hill
摘要：The accelerated failure time model provides a natural formulation of the effects of covariates on potentially censored response variable. The existing semiparametric estimators are computationally intractable and statistically inefficient. In this article we propose an approximate nonparametric maximum likelihood method for the accelerated failure time model with possibly time-dependent covariates. We estimate the regression parameters by maximizing a kernel-smoothed profile likelihood functio...
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作者：Patton, Andrew J.; Timmermann, Allan
作者单位：University of Oxford; University of California System; University of California San Diego
摘要：Empirical tests of forecast optimality have traditionally been conducted under the assumption of mean squared error loss or some other known loss function. In this article we establish new testable properties that hold when the forecaster's loss function is unknown but testable restrictions can be imposed on the data-generating process, trading off conditions on the data-generating process against conditions on the loss function. We propose flexible estimation of the forecaster's loss function...
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作者：Bednorz, Witold; Latuszynski, Krzysztof
作者单位：University of Warsaw; Warsaw School of Economics
