It is well known that unobserved heterogeneity can produce misleading estimates in survival analysis (see for example, Allison, 1995, p.233). The goal of this paper is to show how to estimate and apply a single event timing model with heterogeneity to real data with SAS. We consider three different models: An Exponential-gamma model, when individual-level time-to-event is exponentially distribu...

Nowadays, the search for a distribution capable of modeling the probability density function (PDF) of irradiance data under all conditions of atmospheric turbulence in the presence of aperture averaging still continues. Here, a family of PDFs alternative to the widely accepted Log-Normal and Gamma-Gamma distributions is proposed to model the PDF of the received optical power in free-space optic...

A method for probability density function (PDF) estimation using Bayesian mixtures of weighted gamma distributions, called the Dirichlet process gamma mixture model (DP-GaMM), is presented and applied to the analysis of a laser beam in turbulence. The problem is cast in a Bayesian setting, with the mixture model itself treated as random process. A stick-breaking interpretation of the Dirichlet ...

The generalized master equation or the equivalent continuous time random walk equations can be used to compute the macroscopic first passage time distribution (FPTD) of a complex stochastic system from short-term microscopic simulation data. The computation of the mean first passage time and additional low-order FPTD moments can be simplified by directly relating the FPTD moment generating func...

A multivariate probability model possessing a dependence structure that is reflected in its variance–covariance structure and gamma distributed univariate margins is introduced and studied. In particular, the higher order moments and cumulants, Chebyshevtype inequalities and multivariate probability density functions are derived. The model suggested herein is believed to be capable of describin...

parameter estimation is an important task in the modeling, classification, and detection of radar clutters. radar clutters have stochastic characteristics. therefore, statistical distributions are usually used to describe the features of clutters better. k distribution is one of the most common models utilized to the simulation of clutters. this distribution, which consists of scale and shape p...

Actin is of fundamental importance to all eukaryotic cells. Of the six mammalian actins, beta (beta) and gamma (gamma) cytoplasmic are the isoforms found in all nonmuscle cells and differ by only four amino acids at the amino-terminal region. Both genes are regulated temporally and spatially, though no differences in protein function have been described. Using fluorescent double in situ hybridi...

simulation of gamma and hadron showers in the energy range 100gev- 25tev has been carried out. for a big ideal cherenkov light array, characteristics of lateral distribution of cherenkov photon density have been studied. results from this ideal detector are compared with those simulated for a real tunka- like array to investigate experimental potential of using existence of a hump in lateral di...

The confluent hypergeometric function kind 1 distribution with the probability density function pdf proportional to x −11F1 α; β;−x , x > 0 occurs as the distribution of the ratio of independent gamma and beta variables. In this article, a multivariate generalization of this distribution is defined and derived. Several pertinent properties of this multivariate distribution are discussed that sh...