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作者：Wang, Xiao; Walker, Matthew; Pal, Jayanta; Woodroofe, Michael; Mateo, Mario
作者单位：University System of Maryland; University of Maryland Baltimore; University of Cambridge; University of Michigan System; University of Michigan; University of Michigan System; University of Michigan
摘要：A new nonparametric method is described to estimate the distribution of mass within spherical galaxies. The problem of estimating the mass, M(r), within radius r is converted into a problem of estimating a regression function nonparametrically, subject to shape restriction. We represent the restrictions by the interception of quadratic cones and use the second-order cone programming to estimate the unknown parameters. We establish asymptotic results that are used to construct confidence interv...
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作者：Zhou, Yong; Wan, Alan T. K.; Wang, Xiaojing
作者单位：Shanghai University of Finance & Economics; Chinese Academy of Sciences; Academy of Mathematics & System Sciences, CAS; City University of Hong Kong
摘要：There is a large and growing body of literature on estimating equation (EE) as an estimation approach. One basic property of EE that has been universely adopted in practice is that of unbiasedness, and there are deep conceptual reasons why unbiasedness is a desirable EE characteristic. This article deals with inference from EEs generally leads to EEs that are biased and thus, violates a basic assumption of the EE approach. The main contribution of this article is that it goes beyond existing i...
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作者：Luo, Sheng; Crainiceanu, Ciprian M.; Louis, Thomas A.; Chatterjee, Nilanjan
作者单位：Johns Hopkins University; National Institutes of Health (NIH) - USA; NIH National Cancer Institute (NCI); NIH National Cancer Institute- Division of Cancer Epidemiology & Genetics
摘要：We develop a mixed model to capture the complex stochastic nature of tobacco abuse and dependence. This model describes transition processes among addiction and nonaddiction stages. An important innovation of our model is allowing an unobserved cure state, or permanent quitting, in contrast to transient quitting. This distinction is necessary to model data from situations where censoring prevents unambiguous determination that a person has been cured, Moreover, the processes that described tra...
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作者：Hung, Ying; Zarnitsyna, Veronika; Zhang, Yan; Zhu, Cheng; Wu, C. F. Jeff
作者单位：Rutgers University System; Rutgers University New Brunswick; University System of Georgia; Georgia Institute of Technology; University System of Georgia; Georgia Institute of Technology
摘要：Repeated adhesion frequency assay is the only published method for measuring the kinetic rates of cell adhesion. Cell adhesion plays an important role in many physiological and pathological processes. Traditional analysis of adhesion frequency experiments assumes that the adhesion test cycles are independent Bernoulli trials. This assumption often can be violated in practice. Motivated by the analysis of repeated adhesion tests, a binary time series model incorporating random effects is develo...
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作者：Small, Dylan S.; Rosenbaum, Paul R.
作者单位：University of Pennsylvania
摘要：An instrument manipulates a treatment that it does not entirely control, but the instrument affects the outcome only indirectly through its maipulation of the treatment. The idealized prototype is the randomized encouragement design, in which subjects are randomly assigned to receive either encouragement to accept the treatment or no such encouragement, but not all subjects comply by doing what they are encouraged to do, and the situation is such that only the treatment itself, not disregarded...
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作者：Iversen, Edwin S.; Parmigiani, Giovanni; Chen, Sining
作者单位：Duke University; Johns Hopkins University; Johns Hopkins University; Johns Hopkins University; Johns Hopkins University; Johns Hopkins University
摘要：We describe a method for evaluating an ensemble of predictive models given a sample of observations comprising the model predictions and the outcome event measured with error. Our formulation allows us to simultaneously estimate measurement error parameters, true outcome-the gold standard-and a relative weighting of the predictive scores. We describe conditions necessary to estimate the gold standard and to calibrate these estimates and detail how our approach is related to, but distinct from,...
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作者：Rodriguez, Abel; Dunson, David B.; Gelfand, Alan E.
作者单位：University of California System; University of California Santa Cruz; National Institutes of Health (NIH) - USA; NIH National Institute of Environmental Health Sciences (NIEHS); Duke University
摘要：In multicenter studies subjects in different centers may have different outcome distribution. This article is motivated by the problem of nonparametric modeling of these distributions, borrowing information across centers while also allowing centers to be clustered, Starting with a stick-breaking representation of the Dricichlet process (DP). we replace that random atoms with random probability measures drawn from a DP. This results in a nested DP prior, which can be placed on the collection o...
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作者：Gillen, Daniel L.; Johnson, Wesley O.
作者单位：University of California System; University of California Irvine
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作者：MacEachern, Steven N.
作者单位：University System of Ohio; Ohio State University
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作者：Manuel Pavia, Jose; Larraz, Beatriz; Maria Montero, Jose
作者单位：University of Valencia; Universidad de Castilla-La Mancha
摘要：There exists a large literature on the problem of forecasting election results. But none of the published methods take spatial information into account, although there is clear evidence of geographic trends. To fill this gap, we use geostatical procedures to build a spatial model of voting patterns. We test the model in three close elections and find that it outperforms rival methods in current use. We apply kriging (a spatial model) and cokriging (in a spatiotemporal model version) to improve...
