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作者：Dass, SC; Nair, VN
作者单位：Michigan State University; University of Michigan System; University of Michigan
摘要：Situations with incomplete multivariate spatial data on a lattice are considered. The goal is to impute the missing data in the presence of edges or boundaries and recover the image. Two methods based on Bayesian hierarchical models that iterate between edge detection and spatial smoothing to impute the missing data within identified homogeneous regions are examined. Their performance is compared with another method that imputes the missing values using edge-preserving spatial smoothers with l...
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作者：Ollila, E; Oja, H; Koivunen, V
作者单位：Aalto University; University of Jyvaskyla
摘要：We introduce a new equivariant estimation method of the parameters of the multivariate regression model with q responses and p regressors. The estimate matrix is derived from the lift rank covariance matrix (LRCM) where the lift rank vectors are based on the Oja criterion function. The k = p + q variate ranks and k + I variate lift ranks are constructed using hyperplanes (or fits) going through k observations. The new LRCM regression estimate and the least squares (LS) estimate are shown to be...
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作者：Miglioretti, DL; McCulloch, C; Zeger, SL
作者单位：Group Health Cooperative; General Electric; Johns Hopkins University
摘要：This article introduces a Bayesian hierarchical model for combining information across multiple images, Our work was motivated by an invasive functional brain mapping technique called direct cortical electrical interference that gives a sparse set of binary observations of an underlying ''true'' region at multiple sites on the brain surface. To model region shapes that may vary widely across individuals, we use mixtures of simple templates, for example, circles. These subject-specific template...
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作者：Arcones, MA; Kvam, PH; Samaniego, FJ
作者单位：State University of New York (SUNY) System; Binghamton University, SUNY; University System of Georgia; Georgia Institute of Technology; University of California System; University of California Davis
摘要：For any two random variables X and Y with distributions F and G defined on [0, infinity), X is said to stochastically precede I' if P(X less than or equal to Y) greater than or equal to 1/2. For independent X and 1, stochastic precedence (denoted by X less than or equal to(sp) Y) is equivalent to E[G(X-)] less than or equal to 1/2. The applicability of stochastic precedence in various statistical contexts, including reliability modeling, tests for distributional equality versus various alterna...
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作者：Henderson, R; Shimakura, S; Gorst, D
作者单位：Lancaster University; Universidade Federal do Parana
摘要：In this article we combine ideas from spatial statistics with lifetime data analysis techniques to investigate possible spatial variation in survival of adult acute myeloid leukemia patients in northwest England. Exploratory analysis suggests both clinically and statistically significant variation in survival rates across the region. A multivariate gamma frailty model incorporating spatial dependence is proposed and applied, with results confirming the dependence of hazard on location.
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作者：Stock, JH; Watson, MW
作者单位：Harvard University; National Bureau of Economic Research; Princeton University; Princeton University
摘要：This article considers forecasting a single time series when there are many predictors (N) and time series observations (T). When the data follow an approximate factor model, the predictors can be summarized by a small number of indexes, which we estimate using principal components; Feasible forecasts are shown to be asymptotically efficient in the sense that the difference between the feasible forecasts and the infeasible forecasts constructed using the actual values of the factors converges ...
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作者：Hawkins, DM; Olive, DJ
作者单位：Southern Illinois University System; Southern Illinois University
摘要：Because high-breakdown estimators (HBEs) are impractical to compute exactly in large samples, approximate algorithms are used. The algorithm generally produces an estimator with a lower consistency rate and breakdown value than the exact theoretical estimator. This discrepancy grows with the sample size, with the implication that huge computations are needed for good approximations in large high-dimension samples, The workhorse for HBEs has been the ''elemental set,'' or ''basic resampling,'' ...
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作者：Bartolucci, F; Forcina, A
作者单位：University of Perugia
摘要：In the context of two-way contingency tables, the RC model may be seen as a way of modeling the set of log-odds ratios for adjacent 2 x 2 subtables through row and column scores. This article presents an extended class of RC models that allows simultaneous modeling of the marginal distributions and the association between two categorical variables; these components are parameterized with logits and log-odds ratios that may be of different types (e.g., global or continuation) to suit the nature...
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作者：Reilly, C; Schacker, T; Haase, AT; Wietgrefe, S; Krason, D
作者单位：University of Minnesota System; University of Minnesota Twin Cities; University of Minnesota System; University of Minnesota Twin Cities; University of Minnesota System; University of Minnesota Twin Cities
摘要：Here we investigate the clustering of simian immunodeficiency virus (SIV)-infected cells in a lymphatic tissue sample taken from a rhesus macaque to test a spatial proximity model of the spread of infection. We see that standard methods for analysis of the clustering of point processes are not entirely satisfactory for this application, so we define a novel statistic to understand the clustering in the data. This statistic examines how events spread out from certain points deemed cluster cente...
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作者：Qin, J; Leung, D; Shao, J
作者单位：Memorial Sloan Kettering Cancer Center; Singapore Management University; University of Wisconsin System; University of Wisconsin Madison
摘要：Nonresponse is a very common phenomenon in survey sampling, Nonignorable nonresponse-that is, a response mechanism that depends on the values of the variable having nonresponse-is the most difficult type of nonresponse to handle. This article studies a likelihood-based estimation method for data with nonignorable nonresponse. The likelihood is semiparametric in the sense that it consists of a parametric component for the response mechanism (such as a logistic model) and a nonparametric compone...
