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作者：Paparoditis, E; Politis, DN
作者单位：University of Cyprus; University of California System; University of California San Diego
摘要：The theory developed for bootstrapping unit root tests in an autoregressive (AR) context has been concerned mainly with the large-sample behavior of the methods proposed under the assumption that the null hypothesis is true. No results exist for the relative performance and the power behavior of the bootstrap methods under the alternative. This article studies the properties of different AR bootstrap schemes of the unit root hypothesis, including a new proposal based on unrestricted residuals....
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作者：Farrington, CP; Whitaker, HJ
作者单位：Open University - UK
摘要：Controlling of infectious diseases requires information about the rates at which individuals make contact. We propose a novel approach to modeling contact rates via a continuous contact surface. This provides a more realistic and flexible representation of contact rates than currently used methods. Our approach allows modeling of sources of heterogeneity due to age, individual effects, and gender. The models are fitted to serologic survey data by maximum likelihood. This involves solving an in...
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作者：Yao, F; Müller, HG; Wang, JL
作者单位：Colorado State University System; Colorado State University Fort Collins; University of California System; University of California Davis
摘要：We propose a nonparametric method to perform functional principal components analysis for the case of sparse longitudinal data. The method aims at irregularly spaced longitudinal data, where the number of repeated measurements available per subject is small. In contrast, classical functional data analysis requires a large number of regularly spaced measurements per subject. We assume that the repeated measurements are located randomly with a random number of repetitions for each subject and ar...
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作者：He, SY; Yang, GL; Fang, KT; Widmann, JF
作者单位：Peking University; Peking University; University System of Maryland; University of Maryland College Park; National Institute of Standards & Technology (NIST) - USA; Hong Kong Baptist University; National Institute of Standards & Technology (NIST) - USA
摘要：Phase Doppler interferometry (PDI) is a nonintrusive technique frequently used to obtain information about spray characteristics. Understanding spray characteristics is of critical importance in many areas of science, including liquid fuel spray combustion, spray coatings, fire suppression, and pesticides. PDI measures the size and velocity of individual droplets in a spray. Due to the design of the instrument, recordings of the PDI contain gaps, called dead times. The presence of recurring de...
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作者：Ombao, H; von Sachs, R; Guo, WS
作者单位：University of Illinois System; University of Illinois Urbana-Champaign; University of Illinois System; University of Illinois Urbana-Champaign
摘要：We develop a procedure for analyzing multivariate nonstationary time series using the SLEX library (smooth localized complex exponentials), which is a collection of bases, each basis consisting of waveforms that are orthogonal and time-localized versions of the Fourier complex exponentials. Under the SLEX framework, we build a family of multivariate models that can explicitly characterize the time-varying spectral and coherence properties. Every model has a spectral representation in terms of ...
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作者：Tadesse, MG; Sha, N; Vannucci, M
作者单位：University of Pennsylvania; University of Texas System; University of Texas El Paso; Texas A&M University System; Texas A&M University College Station
摘要：Over the last decade, technological advances have generated an explosion of data with substantially smaller sample size relative to the number of covariates (p >> n). A common goal in the analysis of such data involves uncovering the group structure of the observations and identifying the discriminating variables. In this article we propose a methodology for addressing these problems simultaneously. Given a set of variables, we formulate the clustering problem in terms of a multivariate normal...
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作者：Kim, HM; Mallick, BK; Holmes, CC
作者单位：Konkuk University; Texas A&M University System; Texas A&M University College Station; University of Oxford
摘要：In many problems in geostatistics the response variable of interest is strongly related to the underlying geology of the spatial location. In these situations there is often little correlation in the responses found in different rock strata, so the underlying covariance structure shows sharp changes at the boundaries of the rock types. Conventional stationary and nonstationary spatial methods are inappropriate, because they typically assume that the covariance between points is a smooth functi...
