Biometrika

最新文章

• Semiparametric estimation for the additive hazards model with left-truncated and right-censored data AI翻译
  作者：Huang, Chiung-Yu; Qin, Jing
  作者单位：Johns Hopkins University; Johns Hopkins Medicine; National Institutes of Health (NIH) - USA; NIH National Institute of Allergy & Infectious Diseases (NIAID)
  摘要：Survival data from prevalent cases collected under a cross-sectional sampling scheme are subject to left-truncation. When fitting an additive hazards model to left-truncated data, the conditional estimating equation method (Lin & Ying, 1994), obtained by modifying the risk sets to account for left-truncation, can be very inefficient, as the marginal likelihood of the truncation times is not used in the estimation procedure. In this paper, we use a pairwise pseudolikelihood to eliminate nuisanc...
• Statistics of orthogonal axial frames AI翻译
  作者：Arnold, R.; Jupp, P. E.
  作者单位：Victoria University Wellington; University of St Andrews
  摘要：An orthogonal axial frame is a set of orthonormal unit vectors which are known only up to sign. Such frames arise in crystallography and seismology and as principal axes of multivariate data or of some physical tensors. We develop methods for analysing data of this form. A test of uniformity is given. Parametric models for orthogonal axial frames are presented and tests of location are considered. A brief illustrative example involving earthquakes is given.
• Estimating time-varying effects for overdispersed recurrent events data with treatment switching AI翻译
  作者：Chen, Qingxia; Zeng, Donglin; Ibrahim, Joseph G.; Akacha, Mouna; Schmidli, Heinz
  作者单位：Vanderbilt University; University of North Carolina; University of North Carolina Chapel Hill; Novartis
  摘要：In the analysis of multivariate event times, frailty models assuming time-independent regression coefficients are often considered, mainly due to their mathematical convenience. In practice, regression coefficients are often time dependent and the temporal effects are of clinical interest. Motivated by a phase III clinical trial in multiple sclerosis, we develop a semiparametric frailty modelling approach to estimate time-varying effects for overdispersed recurrent events data with treatment s...
• Inverse probability weighting with error-prone covariates AI翻译
  作者：McCaffrey, Daniel F.; Lockwood, J. R.; Setodji, Claude M.
  作者单位：RAND Corporation
  摘要：Inverse probability-weighted estimators are widely used in applications where data are missing due to nonresponse or censoring and in the estimation of causal effects from observational studies. Current estimators rely on ignorability assumptions for response indicators or treatment assignment and outcomes being conditional on observed covariates which are assumed to be measured without error. However, measurement error is common for the variables collected in many applications. For example, i...
• Bridging the ensemble Kalman and particle filters AI翻译
  作者：Frei, M.; Kuensch, H. R.
  作者单位：Swiss Federal Institutes of Technology Domain; ETH Zurich
  摘要：In many applications of Monte Carlo nonlinear filtering, the propagation step is computationally expensive, and hence the sample size is limited. With small sample sizes, the update step becomes crucial. Particle filtering suffers from the well-known problem of sample degeneracy. Ensemble Kalman filtering avoids this, at the expense of treating non-Gaussian features of the forecast distribution incorrectly. Here we introduce a procedure that makes a continuous transition indexed by gamma[0,1] ...
• Nonparametric estimation of the mean function for recurrent event data with missing event category AI翻译
  作者：Lin, Feng-Chang; Cai, Jianwen; Fine, Jason P.; Lai, Huichuan J.
  作者单位：University of North Carolina; University of North Carolina Chapel Hill; University of Wisconsin System; University of Wisconsin Madison
  摘要：Recurrent event data frequently arise in longitudinal studies when study subjects possibly experience more than one event during the observation period. Often, such recurrent events can be categorized. However, part of the categorization may be missing due to technical difficulties. If the event types are missing completely at random, then a complete case analysis may provide consistent estimates of regression parameters in certain regression models, but estimates of the baseline event rates a...
• Strong orthogonal arrays and associated Latin hypercubes for computer experiments AI翻译
  作者：He, Yuanzhen; Tang, Boxin
  作者单位：Chinese Academy of Sciences; Academy of Mathematics & System Sciences, CAS; Simon Fraser University
  摘要：This paper introduces, constructs and studies a new class of arrays, called strong orthogonal arrays, as suitable designs for computer experiments. A strong orthogonal array of strength t enjoys better space-filling properties than a comparable orthogonal array in all dimensions lower than t while retaining the space-filling properties of the latter in t dimensions. Latin hypercubes based on strong orthogonal arrays of strength t are more space-filling than comparable orthogonal array-based La...
• Blocked two-level regular factorial designs with weak minimum aberration AI翻译
  作者：Zhao, Shengli; Li, Pengfei; Karunamuni, Rohana
  作者单位：Qufu Normal University; University of Waterloo; University of Alberta
  摘要：This paper considers the construction of blocked two-level regular designs with weak minimum aberration. We first obtain the minimum value of the number of two-factor interactions which are aliased with the block effects. Based on this result, two methods are then proposed in two different scenarios to construct weak minimum aberration blocked two-level designs with respect to some existing combined wordlength patterns.
• Two-sample rank tests under complex sampling AI翻译
  作者：Lumley, Thomas; Scott, Alastair J.
  作者单位：University of Auckland
  摘要：Rank tests are widely used for exploratory and formal inference in the health and social sciences. With the widespread use of data from complex survey samples in medical and social research, there is increasing demand for versions of rank tests that account for the sampling design. We propose a general approach to constructing design-based rank tests when comparing groups within a complex sample and when using a national survey as a reference distribution, and illustrate both scenarios with ex...
• Estimation of a sparse group of sparse vectors AI翻译
  作者：Abramovich, Felix; Grinshtein, Vadim
  作者单位：Tel Aviv University; Open University Israel
  摘要：We consider estimating a sparse group of sparse normal mean vectors, based on penalized likelihood estimation with complexity penalties on the number of nonzero mean vectors and the numbers of their significant components, which can be performed by a fast algorithm. The resulting estimators are developed within a Bayesian framework and can be viewed as maximum a posteriori estimators. We establish their adaptive minimaxity over a wide range of sparse and dense settings. A simulation study demo...