The gamma-Weibull distribution revisited

The gamma–Weibull distribution revisited

The five parameter gamma–Weibull distribution has been introduced by Leipnik and Pearce (2004). Nadarajah and Kotz (2007) have simplified it into four parameter form, using hypergeometric functions in some special cases. We show that the probability distribution function, all moments of positive order and the characteristic function of gamma–Weibull distribution of a random variable can be expl...

The Gamma-Exponentiated Weibull Distribution

We study the gamma-exponentiated Weibull distribution which includes as special cases several models such as the exponential, Weibull, exponentiatedWeibull, gamma-exponentiated exponential and exponentiated exponential distributions. This new distribution might be useful for failure time data analysis. We demonstrate that its density function is an infinite linear combination of Weibull densiti...

Weibull-Gamma composite distribution: An alternative multipath/shadowing fading model

Weibull-gamma composite distribution: alternative multipath/shadowing fading model

The Weibull-gamma (WG) distribution, which is appropriate for modelling fading environments when multipath is superimposed on shadowing, is introduced and studied. For this composite distribution the probability density, cumulative distribution, characteristic functions and the moments are derived in closed form. Furthermore, the average bit error and outage probabilities of a receiver operatin...

Hot duplication versus survivor equivalence in Gamma-Weibull distribution

The reliability of composite system (series, parallel) is improved by (i) reduction method, and by (ii) hot duplication, considering the systems survivor function. Related survivor equivalence functions and pointwise survivor equivalence factors are derived in all cases when the components lifetime distribution follow the gamma–Weibull distribution introduced recently by Leipnik and Pearce.