Now showing items 1-10 of 10
Costlets: A Generalized Approach to Cost Functions for Automated Optimization of IMRT Treatment Plans
(Kluwer Academic Publishers; Springer Science + Business Media, Inc., 2005-12)
We present the creation and use of a generalized cost function methodology based on costlets for automated optimization for conformal and intensity modulated radiotherapy treatment plans. In our approach, cost functions ...
Semiparametric Modeling of Longitudinal Measurements and Time-to-Event Data–A Two-Stage Regression Calibration Approach
(Blackwell Publishing Inc, 2008-12)
In this article we investigate regression calibration methods to jointly model longitudinal and survival data using a semiparametric longitudinal model and a proportional hazards model. In the longitudinal model, a biomarker ...
Doubly Penalized Buckley–James Method for Survival Data with High-Dimensional Covariates
(Blackwell Publishing Inc, 2008-03)
Recent interest in cancer research focuses on predicting patients' survival by investigating gene expression profiles based on microarray analysis. We propose a doubly penalized Buckley–James method for the semiparametric ...
A Nonlinear Model with Latent Process for Cognitive Evolution Using Multivariate Longitudinal Data
(Blackwell Publishing Inc, 2006-12)
Cognition is not directly measurable. It is assessed using psychometric tests, which can be viewed as quantitative measures of cognition with error. The aim of this article is to propose a model to describe the evolution ...
Survival Analysis Using Auxiliary Variables Via Multiple Imputation, with Application to AIDS Clinical Trial Data
(Blackwell Publishing Ltd, 2002-03)
We develop an approach, based on multiple imputation, to using auxiliary variables to recover information from censored observations in survival analysis. We apply the approach to data from an AIDS clinical trial comparing ...
Multiple Imputation and Posterior Simulation for Multivariate Missing Data in Longitudinal Studies
(Blackwell Publishing Ltd, 2000-12)
This paper outlines a multiple imputation method for handling missing data in designed longitudinal studies. A random coefficients model is developed to accommodate incomplete multivariate continuous longitudinal data. ...
Counterfactual Links to the Proportion of Treatment Effect Explained by a Surrogate Marker
(Blackwell Publishing, 2005-12)
In a randomized clinical trial, a statistic that measures the proportion of treatment effect on the primary clinical outcome that is explained by the treatment effect on a surrogate outcome is a useful concept. We investigate ...
Direct measurements of thermal vacancies in BCC 4 He
(Kluwer Academic Publishers-Plenum Publishers; Plenum Publishing Corporation ; Springer Science+Business Media, 1987-06)
X-ray lattice parameters of bcc 4 He crystals in contact with superfluid 4 He were measured with 300 ppm accuracy in the temperature range 1.494–1.711 K, corresponding to solid molar volumes between 20.88 and 21.09 cm 3 . ...
A Measure of the Proportion of Treatment Effect Explained by a Surrogate Marker
(Blackwell Publishing Ltd, 2002-12)
Randomized clinical trials with rare primary endpoints or long duration times are costly. Because of this, there has been increasing interest in replacing the true endpoint with an earlier measured marker. However, surrogate ...
Estimation in a Cox Proportional Hazards Cure Model
(Blackwell Publishing Ltd, 2000-03)
Some failure time data come from a population that consists of some subjects who are susceptible to and others who are nonsusceptible to the event of interest. The data typically have heavy censoring at the end of the ...