產能受限定期盤存制之研究

Abstract

本計畫探討產能受限之定期盤存制。定期盤存制在實務上廣泛使用，特別是當許多 商品向同一供應商購買時更是如此。但大部分定期盤存模式皆假設產能是無限的，而實 務上產能卻可能為有限。此現象肇因於供應鏈中之供應商之產能有限(產品外購時)，或 廠商本身之產能受限(產品自己生產時)。 定期盤存文獻雖已有探討產能受限之定期生產模式，並顯示最適政策為一修正之訂 購後水準政策，但對訂購後水準之性質與計算卻無太多著墨。 本計畫使用動態規劃來處理上述定期盤存制。本計畫假設每期需求為獨立且同質分 配，初步研究結果顯示最適訂購後水準應可使用一簡單定理來計算，且可與傳統產能無 限定期盤存制之最適訂購後水準作一比較。本計畫所發展之生產模式易於為業界所應 用。

Periodic review inventory control models are widely used in practice, especially for inventory systems in which many different items are purchased from the same supplier. However, all periodic review models have assumed that the periodic order quantity can be fulfilled. In practice, the periodic order quantity may not be completely fulfilled. Such periodic systems result mainly from the limited production capacity of the upstream supplier (when the item is purchased outside) or the firm itself (when the item is produced in house). Although the production/inventory literature has investigated the capacitated periodic production systems, and showed that the optimal policy is of the modified order-up-to type. The issue of computing the optimal order-up-to level remained unanswered. In this research, we use dynamic programming to model capacitated periodic production systems. We assume that the period demand is independently and identically distributed. Preliminary results show that the optimal order-up-to level can be computed by using a convergence theorem. In addition, we compare it to the ordinary order-up-to level for periodic production systems with unlimited capacity. We believe that the proposed model can be immediately applied in practice.