A Heuristic Method for Solving Bi-Objective Two-Stage Hybrid Flow Shop Scheduling Problem

Abstract

Hybrid flow shop problems are the most widely used in scheduling problems. A two-stage hybrid flow shop can be considered as part of a larger problem we have studied the scheduling of a two-stage hybrid flow shop problem which contains one machine at the first stage and two machines at the second stage with two objectives, the average flow time ( F ) and the average tardiness ( T ). In this paper a heuristic method has been introduced and it has been compared to a multi-objective decision making (lexicography) using simulated annealing (SA) Algorithm on both objective. Eventually, obtained solutions have been solved by simple additive weighting (SAW) method. The weight of criteria have been obtained based on the Shannon Entropy. The result indicated that the proposed heuristic method solution in 90.4% problems has led to better than solutions based on SA Algorithm. The solutions obtained out of 500 problems in heuristic method is 15.04% better than the solutions obtained according to SA Algorithm. And also in heuristic method, the obtained solutions were 58 times faster than SA Algorithm method.