本研究探討二階層存貨配銷系統中，當零售點之間可利用水平緊急轉運機制之上下兩階層存貨控制問題，其中第一階層有一個中央倉儲，第二階層包含多個零售點。俱水平轉運之存貨問題近年來逐漸受到重視，目前探討水平轉運的相關存貨文獻中，大多在既定或已知的存貨控制政策下決定水平轉運之機制，本研究則針對俱水平轉運之二階層存貨問題建立其最佳或近似最佳存貨政策模式，以決定上下階層之最適再訂購點與訂購批量。
　　本研究發展水平緊急轉運之二階層再訂購點暨固定訂購批量期望成本模式，依據隨機理論中之重新報酬過程與定理，進而建構中央倉儲及零售點之庫存與缺貨相關成本，以及重新過程中之期望週期時間，建立單位時間期望總庫存相關成本模式。本研究目的在決定中央倉儲及零售點之最佳再訂購點與訂購批量，使單位時間庫存相關總成本最小化。模式之成本結構包含：中央倉儲訂購成本、中央倉儲存貨持有成本、中央倉儲遇缺補貨成本、零售點訂購成本、零售點存貨持有成本、零售點遇缺補貨成本及零售點發生缺貨時利用水平轉運產生之緊急水平轉運成本。
　　依據所建立俱水平轉運之二階層再訂購點暨固定訂購量期望成本模式，本研究延伸多維搜尋演算法，求得中央倉儲及零售點之最佳再訂購點與訂購批量，使單位時間相關總成本最小化。由演算實驗結果可以發現，在存貨系統總成本表現上，俱水平轉運之二階層存貨系統明顯優於古典之二階層存貨系統，當中央倉儲缺貨成本越低，零售點前置時間越長，水平轉運時間越短，零售點存貨持有成本越高，或零售點缺貨成本越高以及水平轉運成本越低時，使用水平轉運系統的效益越顯著。

　　We consider a two-echelon inventory system with one warehouse and N identical retailers, where lateral transshipment is allowed when stockout occurs in the second echelon. A reorder-point, fixed order-quantity (s, Q) inventory policy is implemented in the system. Leadtimes of the warehouse, the retailers and that of lateral transshipment are all constant, and the retailers face Poisson demand processes. The reorder point and order-quantity of the warehouse are multiples of the retailer order-quantity.
　　The expected total relevant cost model for the described system is developed in the thesis. It includes ordering cost, inventory carrying cost and shortage cost at the warehouse, and ordering cost, inventory carrying cost, shortage cost and lateral transshipment cost at the retailers. A geometric approximation scheme is used to estimate the expected demand rate when retailer faces shortage and transshipment of stock is used to satisfy the demand.
　　A discrete-search heuristic is developed to find the optimal inventory policy. The cost model and its solution procedure is illustrated by a numerical example. Numerical experiments based on fractional factorial design, have shown that the expected operating cost of the system with lateral transshipment is significantly lower than that in the classical model without transshipment. It is advantageous to implement the transshipment policy when the shortage cost of the warehouse is low, the shortage cost of the retailer is high, the retailer lead time is long, the lateral transshipment cost is low, or the lateral transshipment lead time is short.

一、中文部分
彭薇聿，民國九十二年。兩階層可維修商品庫存系統批次存貨模式發展，國立成功大學工業管理研究所碩士論文。
黃俊寧，民國九十三年。二階存貨配銷系統轉運之研究，國立交通大學工業工程與管理研究所博士論文。
李駿宏，民國八十七年。平行供貨二階(S-1, S)存貨系統之研究，國立交通大學工業工程與管理研究所碩士論文。
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