

Articles
by
M. Salah ELSherbeny 
Total Records (
3 ) for
M. Salah ELSherbeny 





G.S. Mokaddis
,
M. Salah ELSherbeny
and
Y. Mahmoud Ayid


Problem statement: In this study we investigated the probabilistic analysis of a twounit warm standby system with constant failure rate and two types of repairmen and patience time. The first repairman, usually called regular repairman, always remained with the repair facility, with the known fact that he might not be able to do some complex repairs within some tolerable (patience) time. An expert repairman was called for the system if and only if the regular repairman is unable to do the job, within some fixed time or on system failure, whichever occurs first. Approach: Techniques of regenerative point processes had been used to measure the system effectiveness Results: The timedependent availability, steadystate availability, reliability, (MTTF) and profit function were obtained numerically and graphically. Conclusion: The availability and profit decreased with respect to the increase of failure rate. 




G.S. Mokaddis
,
M. Salah ELSherbeny
and
Entesar AlEsayeh


Problem statement: This study presented the reliability and Mean Time To System Failure (MTTF) analysis of a twostate complex with repairable system, consisting of two subsystems A and B arranged in series, incorporating the concept of hardware and human failures. The failure times of operating units and repair time of failed units were exponential distributed. Approach: Markovrenewal processes and properties of Laplace transforms had been used to measure the system effectiveness Results: Laplace transforms of the various state probabilities had been derived and then reliability of the complex system, at any time t, had been computed by inversion process. MTTF had also been evaluated; availability and steadystate availability for system was derived. Certain important result had been evaluated as special cases. Also, few graphical illustrations were also given at the end to highlight the important results. Conclusion: The additional repair led to improve the values of the MTTF and the reliability at any time t. 





Mervat M.K. Elshafei
and
M. Salah ELSherbeny


In this study, consider Bilevel multiobjective stochastic integer linear programming (BLMOILP) problem with chance constraints. Assume that there is randomness in the righthand sides of the constraints only and that the random variables are normal distributed. An interactive algorithm for solving such problem is presented. By using the chanceconstrained programming technique, the problem converted from probalistic into deterministic bilevel multiobjective integer linear programming (DBLMOILP) problem. This problem can be transform into separate multiobjective decision making problems and solving it by using εconstraint method. Finally, an illustrative numerical example is given to demonstrate the obtained results. 





