Mean life of k-to-l-out-of-n systems with nonidentical Weibull distribution components

A k-to-l-out-of-n system is a noncoherent system in which no fewer than k and no more than l out of n units are to function for the successful operation of the system. Examples of noncoherent systems are found in communication, multiprocessor and transportation systems. A noncoherent system is very general and includes the parallel, series and N-Modular Redundancy (NMR) systems as special cases. In this paper presents the formulas for calculating the reliability and the mean life of a k-to-l-out-of-n system with non-identical weibull distribution components.