Summary: | 碩士 === 國立交通大學 === 工業工程與管理系所 === 101 === Theory of Constraints proposed using demand-pull replenishment policy and buffer management to manage supply chain inventory. Compared with traditional replenishment policy such as (s, S)、(s, Q)、(R, S)、(R, s, S), this policy better suits for a dynamic production environment by taking immediate demand information into consideration. Moreover, in this policy, there is no need to concern a complicated parameter setting. However, in the semiconductor industry, most of the products have short product life cycle, long production lead time and protean demand characteristics. In this situation, if we only use the replenishment policy and buffer adjustment method proposed by TOC, it may be unable to respond to changes in demand timely and result in the risks of too much inventory or out of stock. This study proposes a method by integrating historical demand and the rolling forecast from market demand by exponentially weighted moving average (EWMA) to observe the demand trends and decide the timing of buffer adjustment according to the inventory level.
To test the validity and feasibility of the method the study proposed, we apply the method to the real historical data from Taiwanese wafer foundry plant and other simulation data. The results show that compared with the past studies concerning the historical demand information or forecasting information individually, the method we proposed has lower average inventory and higher service level, making demand-pull replenishment policy more suitable for the products with long production lead time and protean demand characteristics.
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