Journal of Computational & Graphical Statistics articles from December 2000

Journal of Computational & Graphical Statistics archives from December 2000

An S-Plus Implementation of Hidden Markov Models in Continuous Time.
December 1, 2000... Hidden Markov models (HMM) can be applied to the study of time varying unobserved categorical variables for which only indirect measurements are available. An S-Plus module to fit HMMs in continuous time to this type of longitudinal data is...

Constrained Nonparametric Maximum Likelihood via Mixtures.
December 1, 2000... This article discusses a new technique for calculating maximum likelihood estimators (MLEs) of probability measures when it is assumed the measures are constrained to a compact, convex set. Measures in such sets can be represented as mixtures...

An Algorithm for Robust Inference for the Cox Model With Frailties.
December 1, 2000... This article proposes a robust method of statistical inference for the Cox's proportional hazards model with frailties. We use the Metropolis-Hastings algorithm and the bootstrap method. We present a computationally efficient algorithm with a...

Image Restoration Using Modifications of Simulated Annealing.
December 1, 2000... This article uses a modified version of the simulated annealing algorithm to restore degraded spatial patterns. Standard simulated annealing is used to find an image that is a posterior mode when the number of images under consideration...

Cluster Analysis for Large Datasets: An Effective Algorithm for Maximizing the Mixture Likelihood.
December 1, 2000... The primary model for cluster analysis is the latent class model. This model yields the mixture likelihood. Due to numerous local maxima, the success of the EM algorithm in maximizing the mixture likelihood depends on the initial starting point...

The Simplified Component Technique: An Alternative to Rotated Principal Components.
December 1, 2000... It is fairly common, following a principal component analysis, to rotate components in order to simplify their structure. Here, we propose an alternative to this two-stage procedure which involves only one stage and combines the objectives of...

Computational Aspects of Nonparametric Bayesian Analysis With Applications to the Modeling of Multiple Binary Sequences.
December 1, 2000... We consider Markov mixture models for multiple longitudinal binary sequences. Prior uncertainty in the mixing distribution is characterized by a Dirichlet process centered on a matrix beta measure. We use this setting to evaluate and compare...

Graphical Exploratory Analysis of Survival Data.
December 1, 2000... We present dynamic and static graphs for exploratory analysis of survival data. These graphs are based on a smooth semiparametric estimate of the survival probability as a function of time and a covariate. We overlay a contour plot of the...

The Partial Scatterplot Matrix.
December 1, 2000... The marginal dependence structure of a dataset y is displayed by a scatterplot matrix, a matrix whose elements are scatterplots of each pair of variables. A natural way to view the conditional dependence structure of y is through a partial...

The Histogram and Boxplot for the Display of Lifetime Data.
December 1, 2000... The importance of histograms and boxplots as exploratory data analysis (EDA) tools has been well established. Yet, adopting them for lifetime data is not straightforward. The first problem, particularly in histograms, is how to deal with...

Bayesian Inference With Missing Data Using Bound and Collapse.
December 1, 2000... Current Bayesian methods to estimate conditional probabilities from samples with missing data pose serious problems of robustness and computational efficiency. This article introduces a new method, called bound and collapse (BC) to tackle these...