FH 2(P 2,P 2) hybrid flow shop scheduling with recirculation of jobs

Abstract

In this paper, two hybrid flow shop scheduling problems to minimize the makespan are presented. The first is the hybrid flow shop on two stages with only one machine on each stage and recirculation of jobs. This problem is polynomial. The second one is the hybrid flow shop on two stages such as each one contains two identical parallel machines and every job recirculates a finite number of times. This problem is NP- hard in general. Linear mathematical formulation and heuristics are also presented with numerical experimentations