Bicriteria Scheduling Problem on the Two-Machine Flowshop Using Simulated Annealing

Real life scheduling problems require the decision maker to consider a number of criteria before arriving at any decision. The trade-offs involved in considering several different criteria provide useful insights for the decision maker. Surprisingly, research in the field of multi-objective scheduling has been quite limited when compared to research in single criterion scheduling. The subject of this paper is the bicriteria scheduling problem in a two-machine flowshop. The objective is to find a job sequence that minimizes sum of weighted total flowtime and total tardiness. Based on the problem characteristics, a Simulated Annealing algorithm is developed. The proposed meta-heuristic is compared with the branch and bound enumeration algorithm of the integer programming model as well as a modified version of the well-known NEH algorithm. During these evaluations, the experimental design approach and careful statistical analysis have been used to validate the effectiveness of the simulated annealing approach.