아웃소싱 리드타임을 고려하는 두 단계 흐름작업라인에서 완료시간의 가중총합을 최소화하는 유전 알고리즘 연구

This paper considers a scheduling problem of two machine flowshop system with outsourcing strategy. There are two machines in this model, and each job has two tasks. When a job is outsourced, the first task is outsourced to a subcontractor, but the second task must be delivered from the subcontractor and processed in-house. Outsourcing jobs incur outsourcing lead-time as well as costs, and the lead-time menas constraints on the possibility of starting a second task of outsourcing job after the outsourcing lead-time. The objective of this paper is to find a solution that minimizes the weighted sum of outsourcing costs and total weighted completion times. For this problem, we investigate the properties of optimal solutions and propose some heuristics and a Biased Random Key Genetic Algorithm. We then conduct extensive computational experiments on various settings, and show that the derived algorithms find efficient solutions in reasonable time.