Multi-Objective Optimization Issues in Short-Term Batch Scheduling

In this article, we propose a multiple objective optimization based approach for the short term scheduling of batch plants to select superior solutions when compared to the single objective problem. Two alternate approaches to optimality, viz. lexicographic and pareto-optimality based formulations are considered here. We demonstrate the suitability of lexicographic optimization for the case when the importance associated with the objectives is known a priori. Next, we also show the practicality of the pareto-optimization based approach when an explicit precedence ordering of the objectives is not known. Case studies involving the objectives of make-span minimization and profit maximization problem are considered here in the discrete state task network representation of (Kondili et al., 1993), to demonstrate the practicality of the above approaches, towards deciding on operating schedules.