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作者：Kleiber, William; Katz, Richard W.; Rajagopalan, Balaji
作者单位：University of Colorado System; University of Colorado Boulder; National Center Atmospheric Research (NCAR) - USA; University of Colorado System; University of Colorado Boulder
摘要：Spatiotemporal simulation of minimum and maximum temperature is a fundamental requirement for climate impact studies and hydrological or agricultural models. Particularly over regions with variable orography, these simulations are difficult to produce due to terrain driven nonstationarity. We develop a bivariate stochastic model for the spatiotemporal field of minimum and maximum temperature. The proposed framework splits the bivariate field into two components of local climate and weather. Th...
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作者：Jiang, Xun; Dey, Dipak K.; Prunier, Rachel; Wilson, Adam M.; Holsinger, Kent E.
作者单位：University of Connecticut; Yale University; Connecticut State University System; Western Connecticut State University; University of Connecticut
摘要：Understanding the mechanisms that allow biological species to co-occur is of great interest to ecologists. Here we investigate the factors that influence co-occurrence of members of the genus Protea in the Cape Floristic Region of southwestern Africa, a global hot spot of biodiversity. Due to the binomial nature of our response, a critical issue is to choose appropriate link functions for the regression model. In this paper we propose a new family of flexible link functions for modeling binomi...
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作者：Imai, Kosuke; Ratkovic, Marc
作者单位：Princeton University
摘要：When evaluating the efficacy of social programs and medical treatments using randomized experiments, the estimated overall average causal effect alone is often of limited value and the researchers must investigate when the treatments do and do not work. Indeed, the estimation of treatment effect heterogeneity plays an essential role in (1) selecting the most effective treatment from a large number of available treatments, (2) ascertaining subpopulations for which a treatment is effective or ha...
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作者：Fu, Audrey Qiuyan; Russell, Steven; Bray, Sarah J.; Tavare, Simon
作者单位：University of Cambridge; University of Cambridge; University of Cambridge; University of Southern California
摘要：To identify novel dynamic patterns of gene expression, we develop a statistical method to cluster noisy measurements of gene expression collected from multiple replicates at multiple time points, with an unknown number of clusters. We propose a random-effects mixture model coupled with a Dirichlet-process prior for clustering. The mixture model formulation allows for probabilistic cluster assignments. The random-effects formulation allows for attributing the total variability in the data to th...
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作者：Rusch, Thomas; Lee, Ilro; Hornik, Kurt; Jank, Wolfgang; Zeileis, Achim
作者单位：Vienna University of Economics & Business; Vienna University of Economics & Business; University of New South Wales Sydney; State University System of Florida; University of South Florida; University of Innsbruck
摘要：In political campaigning substantial resources are spent on voter mobilization, that is, on identifying and influencing as many people as possible to vote. Campaigns use statistical tools for deciding whom to target (microtargeting). In this paper we describe a nonpartisan campaign that aims at increasing overall turnout using the example of the 2004 US presidential election. Based on a real data set of 19,634 eligible voters from Ohio, we introduce a modern statistical framework well suited f...
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作者：Chandler, Richard B.; Royle, J. Andrew
作者单位：United States Department of the Interior; United States Geological Survey
摘要：Recently developed spatial capture-recapture (SCR) models represent a major advance over traditional capture-recapture (CR) models because they yield explicit estimates of animal density instead of population size within an unknown area. Furthermore, unlike nonspatial CR methods, SCR models account for heterogeneity in capture probability arising from the juxtaposition of animal activity centers and sample locations. Although the utility of SCR methods is gaining recognition, the requirement t...
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作者：Gramacy, Robert B.; Taddy, Matt; Wild, Stefan M.
作者单位：University of Chicago; United States Department of Energy (DOE); Argonne National Laboratory; University of Chicago; University of Chicago
摘要：We investigate an application in the automatic tuning of computer codes, an area of research that has come to prominence alongside the recent rise of distributed scientific processing and heterogeneity in high-performance computing environments. Here, the response function is nonlinear and noisy and may not be smooth or stationary. Clearly needed are variable selection, decomposition of influence, and analysis of main and secondary effects for both real-valued and binary inputs and outputs. Ou...
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作者：Gaydos, Travis L.; Heckman, Nancy E.; Kirkpatrick, Mark; Stinchcombe, J. R.; Schmitt, Johanna; Kingsolver, Joel; Marron, J. S.
作者单位：MITRE Corporation; University of British Columbia; University of Texas System; University of Texas Austin; University of Toronto; University of California System; University of California Davis; University of North Carolina; University of North Carolina Chapel Hill; University of North Carolina; University of North Carolina Chapel Hill
摘要：Principal Components Analysis (PCA) is a common way to study the sources of variation in a high-dimensional data set. Typically, the leading principal components are used to understand the variation in the data or to reduce the dimension of the data for subsequent analysis. The remaining principal components are ignored since they explain little of the variation in the data. However, evolutionary biologists gain important insights from these low variation directions. Specifically, they are int...
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作者：Kleiber, William; Sain, Stephan R.; Heaton, Matthew J.; Wiltberger, Michael; Reese, C. Shane; Bingham, Derek
作者单位：University of Colorado System; University of Colorado Boulder; Brigham Young University; Brigham Young University; Simon Fraser University
摘要：Geomagnetic storms play a critical role in space weather physics with the potential for far reaching economic impacts including power grid outages, air traffic rerouting, satellite damage and GPS disruption. The LFM-MIX is a state-of-the-art coupled magnetospheric-ionospheric model capable of simulating geomagnetic storms. Imbedded in this model are physical equations for turning the magnetohydrodynamic state parameters into energy and flux of electrons entering the ionosphere, involving a set...
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作者：Stein, Michael L.; Chen, Jie; Anitescu, Mihai
作者单位：University of Chicago; United States Department of Energy (DOE); Argonne National Laboratory
摘要：We discuss the statistical properties of a recently introduced unbiased stochastic approximation to the score equations for maximum likelihood calculation for Gaussian processes. Under certain conditions, including bounded condition number of the covariance matrix, the approach achieves O(n) storage and nearly O(n) computational effort per optimization step, where n is the number of data sites. Here, we prove that if the condition number of the covariance matrix is bounded, then the approximat...
