Multi-objective optimization in an identical parallel flow shop scheduling problem with waiting time constraint

The Operations Research community has grown interested in scheduling problems within flow shop systems. Despite this, the Identical Parallel Flow Shop Scheduling Problem (IPFSSP) remains underexplored, especially with multiple objective functions. This paper aims to bridge this gap by developing a scheduling strategy for an Identical Parallel Flow Shop Scheduling Problem with a bicriteria objective, focusing on Makespan and the total Earliness and Tardiness of jobs while considering Waiting time constraint. The study employs both a priori and a posteriori methods to address the problem. The main contribution of this work is the integration of algorithmic components designed to balance the loads across flow shop lines within the proposed algorithms. A series of test instances are utilized to evaluate the performance of the proposed algorithms, which is then compared to a lower bound. Experimental results demonstrate that each method presents distinct advantages and limitations regarding convergence, optimality, and computation time for addressing multi-objective IPFSSP challenges.