-
作者：Ibrahim, JG; Chen, MH; Lipsitz, SR; Herring, AH
作者单位：University of North Carolina; University of North Carolina Chapel Hill; University of Connecticut; Medical University of South Carolina
摘要：Missing data is a major issue in many applied problems, especially in the biomedical sciences. We review four common approaches for inference in generalized linear models (GLMs) with missing covariate data: maximum likelihood (ML), multiple imputation (MI), fully Bayesian (FB), and weighted estimating equations (WEEs). There is considerable interest in how these four methodologies are related, the properties of each approach, the advantages and disadvantages of each methodology, and computatio...
-
作者：Sánchez, BN; Budtz-Jorgensen, E; Ryan, LM; Hu, H
作者单位：Harvard University; Harvard T.H. Chan School of Public Health; University of Copenhagen
摘要：Structural equation models (SEMs) have been discussed extensively in the psychometrics and quantitative behavioral sciences literature. However, many statisticians and researchers in other areas of application are relatively unfamiliar with their implementation. Here we review some of the SEM literature and describe basic methods, using examples from environmental epidemiology. We make connections to recent work on latent variable models for multivariate outcomes and to measurement error metho...
-
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...
-
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 ...
-
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...
-
作者：Song, PXK; Fan, YQ; Kalbfleisch, JD
作者单位：University of Waterloo; Vanderbilt University; University of Michigan System; University of Michigan
摘要：This article presents and examines a new algorithm for solving a score equation for the maximum likelihood estimate in certain problems of practical interest. The method circumvents the need to compute second-order derivatives of the full likelihood function. It exploits the structure of certain models that yield a natural decomposition of a very complicated likelihood function. In this decomposition, the first part is a log-likelihood from a simply analyzed model, and the second part is used ...
-
作者：Lee, BL; Kosorok, MR; Fine, JP
作者单位：National University of Singapore; University of Wisconsin System; University of Wisconsin Madison; University of Wisconsin System; University of Wisconsin Madison
摘要：We consider frequentist inference for the parametric component 0 separately from the nuisance parameter eta in semiparametric models based on sampling from the posterior of the profile likelihood. We prove that this procedure gives a first-order-correct approximation to the maximum likelihood estimator 0,, and consistent estimation of the efficient Fisher information for 0, without computing derivatives or using complicated numerical approximations. An exact Bayesian interpretation is establis...
-
作者：Lou, XY; Casella, G; Todhunter, RJ; Yang, MCK; Wu, RL
作者单位：State University System of Florida; University of Florida; Cornell University; Zhejiang A&F University
摘要：The nonrandom association between different genes, termed linkage disequilibrium (LD), provides a powerful tool for high-resolution mapping of quantitative trait loci (QTL) underlying complex traits. This LD-based mapping approach can be made more efficient when it is coupled with interval mapping characterizing the genetic distance between markers and QTL. This article describes a general statistical framework for simultaneously estimating the linkage and LD that are related in a two-stage hi...
-
作者：Xu, K; Wikle, CK; Fox, NI
作者单位：University of Missouri System; University of Missouri Columbia; University of Missouri System; University of Missouri Columbia
摘要：A good short-period forecast of heavy rainfall is essential for many meteorological and hydrological applications. Traditional deterministic and stochastic nowcasting methodologies have been inadequate in their characterization of pixelwise rainfall reflectivity propagation, intensity, and uncertainty. The methodology presented herein uses an approach that efficiently parameterizes spatio-temporal dynamic models in terms of integro-difference equations within a hierarchical framework. The appr...
-
作者：Peña, D; Sánchez, I
摘要：This article presents a new procedure for multifold predictive validation in time series. The procedure is based on the so-called filtered residuals, in-sample prediction errors evaluated in such a way that they are similar to out-of-sample ones. The filtered residuals are obtained from parameters estimated by eliminating from the estimation process the estimated innovations at the points to be predicted. Thus, instead of using the deletion of observations to validate the predictions, as in cl...
