We study nonparametric maximum likelihood estimation of a log–concave probability density and its distribution and hazard function. Some general properties of these estimators are derived from two characterizations. It is shown that the rate of convergence with respect to supremum norm on a compact interval for the density and hazard rate estimator is at… (More)
Maximum likelihood estimation of a log-concave density has attracted considerable attention over the last few years. Several algorithms have been proposed to estimate such a density. Two of those algorithms, an iterative convex minorant and an active set algorithm , are implemented in the R package logcondens. While these algorithms are discussed elsewhere,… (More)
Dissociative disorders are frequent comorbid conditions of other mental disorders. Yet, there is controversy about their clinical relevance, and little systematic research has been done on how they influence global functioning. Outpatients and day care patients (N=160) of several psychiatric units in Switzerland were assessed with the Structured Clinical… (More)
We develop an active set algorithm for the maximum likelihood estimation of a log–concave density based on complete data. Building on this fast algorithm, we introduce an EM algorithm to treat arbitrarily censored data, e.g. right–censored or interval–censored data.
We find limiting distributions of the nonparametric maximum likelihood estimator (MLE) of a log-concave density, i.e. a density of the form f(0) = exp varphi(0) where varphi(0) is a concave function on R. Existence, form, characterizations and uniform rates of convergence of the MLE are given by Rufibach (2006) and Dümbgen and Rufibach (2007). The… (More)
The study of chronic brain diseases including Alzheimer's disease in patients is typically limited to brain imaging or psychometric testing. Given the epidemic rise and insufficient knowledge about pathological pathways in sporadic Alzheimer's disease, new tools are required to identify the molecular changes underlying this disease. We hypothesize that… (More)
Marshall's [Nonparametric Techniques in Statistical Inference (1970) 174–176] lemma is an analytical result which implies √ n–consistency of the distribution function corresponding to the Grenander [Skand. Aktuari-etidskr. 39 (1956) 125–153] estimator of a non-decreasing probability density. The present paper derives analogous results for the setting of… (More)
INTRODUCTION Erosions of the sacroiliac joints (SIJ) on pelvic radiographs of patients with ankylosing spondylitis (AS) are an important feature of the modified New York classification criteria. However, radiographic SIJ erosions are often difficult to identify. Recent studies have shown that erosions can be detected also on magnetic resonance imaging (MRI)… (More)
OBJECTIVE To assess intra-, inter-reader agreement, and the agreement between two software packages for magnetic resonance diffusion tensor imaging (DTI) measurements of the median nerve. MATERIALS AND METHODS Fifteen healthy volunteers (seven men, eight women; mean age, 31.2 years) underwent DTI of both wrists at 1.5 T. Fractional anisotropy (FA) and… (More)
In statistical analysis reports, tables with descriptive statistics are routinely presented. We introduce the R package reporttools containing functions to efficiently generate such tables when compiling statistical analyses reports by combining L A T E X and R via Sweave.