https://scholars.lib.ntu.edu.tw/handle/123456789/625532
標題: | Production control under process queue time constraints in systems with a common downstream workstation | 作者: | Chen Y.-T CHENG-HUNG WU Tien Y.-J Yu C.-J. |
關鍵字: | Common machines; Dynamic programming; Equipment health; Production control; Queue time constraints | 公開日期: | 2016 | 卷: | 23 | 期: | 5 | 起(迄)頁: | 349-371 | 來源出版物: | International Journal of Industrial Engineering : Theory Applications and Practice | 摘要: | This research develops a dynamic production control method for two-product manufacturing systems under process queue time (PQT) constraints. In which, while two different products are being processed at two upstream workstations, a common downstream workstation is shared by both products. PQT constraints before the downstream common workstation are assumed. Under PQT constraints, waiting time of jobs in the downstream queue is constrained by predefined upper limits. When a work-in-process (WIP) waits in the downstream queue longer than the predefined upper limit, the WIP may be scrapped or the yield quality may deteriorate seriously. When machines are unreliable, random machine failures cause high waiting time variance and significantly increase the risk of violating PQT constraints. Therefore, for production systems with PQT constraints, a robust dynamic scheduling method with real time machine reliability considerations is critical. In this research, a Markov decision process (MDP) model is developed to explicitly consider real time machine reliability status and real time WIP distribution. The objective is to find optimal dynamic admission control policies for the upstream workstations and optimal priority control policies for the downstream common workstation. The MDP model aims to minimize expected long-run average production costs, which are the sum of waiting costs and scrap costs. To minimize total costs, a good control model should balance the need for low scrap rates and low waiting costs. In our numerical study, the robustness of the proposed control method is shown by discrete event simulation. Compared with other control methods in literature, the proposed method reduces production costs by at least 27.6% on average. © International Journal of Industrial Engineerings. |
URI: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-85016008202&partnerID=40&md5=eaafe3cb0d182ae6c5c42034cd9e4426 https://scholars.lib.ntu.edu.tw/handle/123456789/625532 |
ISSN: | 10724761 | SDG/關鍵字: | Costs; Discrete event simulation; Dynamic programming; Industrial research; Markov processes; Numerical methods; Production control; Queueing theory; Real time systems; Semiconductor device manufacture; Control methods; Dynamic production; Dynamic scheduling methods; Markov Decision Processes; Optimal dynamics; Priority control; Production system; Queue time constraint; Process control |
顯示於: | 工業工程學研究所 |
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