Heuristics for Scheduling in Flexible Flowshops Minimize the Makespan and Total Flowtime of Jobs

摘要

This research attempts to solve a flexible flowshop bicriteria scheduling problem, in which the objective function is to minimize a weighted sum of total flowtime and makespan. Because of the NP-hardness of the integer linear programming model of the considered problem, heuristics within two major groups based on modifying two better performing flowshop heuristics for their performances of makespan namely NEH and CDS are proposed. Computational experiments show that the best NEH based heuristics perform better than the best CDS based heuristics. The experiments also show that the best NEH based heuristics are relatively efficient when their results are compared with the lower bounds proposed in this study.