Random search algorithms for redundancy allocation problem of a queuing system with maintenance considerations

• Published in: Reliability engineering & system safety 2019-05, Vol.185, p.144-162
• Main Authors: Sabri-Laghaie, Kamyar, Karimi-Nasab, Mehdi
• Format: Article
• Language: English
• Subjects: Algorithms; Queues; Queuing system; Queuing theory; Random search algorithm; Redundancy; Redundancy Allocation Problem (RAP); Reliability analysis; Reliability engineering; Repairman; Search algorithms; Standby server; System reliability
• ISSN: 0951-8320; 1879-0836
• DOI: 10.1016/j.ress.2018.12.010

•In this paper a Redundancy Allocation problem (RAP) for a queueing system is modeled.•Optimal number of repairmen and redundant servers are found by which queueing and maintenance costs are minimized.•Four random search algorithms are developed to deal with different structures of solution space.•Two algorithms for unimodal objective functions and two algorithms for multimodal objective functions are developed. The Redundancy Allocation Problem (RAP) is becoming all the time more important in system reliability design. Therefore, RAP has been studied vastly for different systems and under various assumptions. One of the important systems that RAP can be applied to them is queuing systems. In many applications, reliability of queuing systems need to be improved with regard to some queuing and reliability cost constraints. Despite the importance of queuing systems in real world situations, RAP of these systems have not gained attention in the literature. Therefore, RAP of a queuing system with maintenance considerations and including queueing costs in the modeling of RAP is considered in this paper. To find optimal solutions of the problem, four random search algorithms are developed and compared based on the problem structures. According to the experiments, for unimodal solution spaces algorithms 1 and 2 and for multimodal solution spaces algorithms 3 and 4 are recommended.