Supply Chain Monitoring Schemes for Echelon WIP Inventory Considering Capacity Limitation

• Main Authors: Mei-Shian Guo, 郭美��
• Other Authors: 郭瑞祥
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/02275200717097495648

碩士 === 國立臺灣大學 === 工業工程學研究所 === 95 === With fiercer and fiercer competition, the integration among the enterprises is getting more and more important. The power which the members owned in the supply chain is not equal and the goals of the members of supply chain always pursue for their own profits, not the profits of whole supply chain. As a result, this leads to poor performance of supply chain. Besides, capacity utilization effects on some other performance indexes with each other. Too high or low capacity utilization makes negative effects. Therefore, considering capacity limitation, in order to enhance the service levels and improve the performance of the whole supply chain, it is essential for all members to share their information and synchronize their operations. This research attempts to develop a supply chain monitoring scheme based on the concepts of echelon WIP inventory and CONWIP system. The first step in the proposed scheme is to construct a two-echelon model which takes the features of the production system into consideration with the goal of minimizing the echelon WIP inventory control limits of the supply chain under the service level constraints. Next, the model is extended to a multi-echelon model through raising the service levels of the internal echelons and solving the model iteratively. The algorithm searches the proper internal service level with the concept of binary search. With the resulting echelon WIP inventory control limits from the model, the proposed monitoring scheme has been validated through simulation study. Based on the simulation validation results, the conclusions are drawn as follows: (1) By raising the service levels of internal echelons, the proposed scheme can effectively derive the multi-echelon WIP inventory limits, which is lower than the stage-based WIP inventory limits of the supply chain which is predominated by the back-end members but higher than the front-end members; (2) Compared to the traditional stage-based inventory monitoring scheme, the proposed echelon-based monitoring scheme can obtain a higher service level under the lower inventory levels. This is the result of reallocating of the WIP limits and the utilizing of overall information.