MULTI– OBJECTIVE FLEXIBLE OPEN SHOP SCHEDULING PROBLEM USING MODIFIED DISCRETE FIREFLY ALGORITHM (MFOSSP)

ABSTRACT In this paper, flexible open shop scheduling problem using modified discrete firefly algorithm(MFOSSP-DFA) is studied in the case of optimizing different contradictory objectives consisting of (i) make span (ii) maximal machine workload (iii) total workload (iv) machine idle time (v) total tardiness. The main constraints of this scheduling problem are that each operation has to be processed without preemptive by exactly only one machine at one stage (i.e) no ordering constraints on operations. It is very difficult to adopt the situations where the undertakings making up an occupation can be performed in any request. Despite the fact that it is unrealistic to convey out more than one task at any particular time. It is non polynomial- hard problem. So its complexity is more. Because of its high complexity many researchers found difficult to solve using classical optimization methods. In this study, firefly algorithm is embraced to take care of the issue in which the machine task and operation arrangement are handled by constructing a correct conversion of the continuous functions as attractiveness, distance and movement into new discrete functions. Benchmark problems are used to evaluate and study the performance of the firefly algorithm. The final result shows that the firefly algorithm produced better results than other author's algorithm