Ammar M. Sarhan

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The exponential, Rayleigh, linear failure rate and Weibull distributions are the most commonly used distributions for analyzing lifetime data. These distributions have several desirable properties and nice physical interpretations. This paper introduces a new distribution named modified Weibull distribution. This distribution generalizes the following(More)
The reliability equivalence factors of a parallel system with n independent and identical components are obtained. The failure rates of the system’s components are assumed to be constant. Three different methods are used to improve the given system. The mean times to failures of the original and improved systems are obtained. A comparison between the mean(More)
The aim of this work is to generalize reliability equivalence technique to apply it to a general series-parallel system consists of n subsystems connected in series, and each subsystem i has i m components connected in parallel system, with mixing life time and delayed time. We derive the reliability and mean time to failure of the original and improved(More)
This paper extends the concept of reliability equivalence from simple series and parallel systems to some complex systems. The reliability equivalence factors of a complex system are obtained. We consider a radar system in an aircraft, which consists of three independent and non-identical components. Both survival function and mean time to failure are used(More)
In this paper we study equivalence of different designs of a four independent and identical components series–parallel system. The failure rates of the system components are assumed to be constant. Then two types of reliability equivalence factors of the system are obtained. Numerical studies are given in order to explain how one can utilize the theoretical(More)
This paper is concerned with the development of a production inventory model for both ameliorating and deteriorating items. Given an inventory goal level and a production goal rate set by the production facility, and given penalties for the inventory level and for the production rate to deviate from their respective targets, a system total cost objective(More)