多階層供應鏈存貨策略之績效研究

A Study on Performance of Inventory Policies in a Multi-Stage Supply Chain System

陳勝杰(Sheng-Chieh Chen)

指導教授 ： 洪弘祈

朝陽科技大學/理工學院/工業工程與管理系/碩士(2010年)

摘要

存貨策略的制定直接影響了企業的營運，在市場需求不確定性下，存貨不足易造成銷售損失。尤其是短生命週期產品，一旦錯過了需求高峰期，便失去了產品在市場上販售的價值。本研究將探討採用不同存貨策略對供應鏈績效之影響，並透過系統模擬的方式探討三種不同需求型態的存貨策略，提出最適合的存貨策略。
本研究中採用系統模擬建構四階層的供應鏈系統，分別為供應商、製造商、物流中心以及零售商，並將供應商、製造商與物流中心歸類為上游，零售商則歸類為下游，研究中探討需求集中於期初、期中或期末的產品生命週期型態較佳的存貨策略。主要考慮的策略為RQ、TS；以及上下游分別為RQ或TS之混合策略。本研究最後針對不同產品生命週期產品之三種需求型態，進行敏感度分析。
本研究結果顯示：1. RQ策略之平均持有量較低，但其缺貨量較高，原因在於該策略是以經濟訂購量(EOQ)為基礎，當需求變化較大時，RQ策略並無法及時修正訂購量易造成缺貨。2. TS策略之平均缺貨量較低，但其持有量較高，原因在於該策略在固定週期下監控存貨水準，且對整個週期預測之需求計算一個最高存貨量，每次訂購都滿足此最高存貨，但當需求量小於存貨量時易造成存貨之堆積。3.敏感度分析，主要探討成本的變動是否會改變最佳策略之選取，在經過模擬實驗後發現持有成本與缺貨成本，在不同系統參數設定上均會對系統執行績效造成影響，因此為選取最佳存貨策略，運用PSR圖形的分析，找出在各需求型態的成本參數設定下最佳存貨策略。

關鍵字

產品生命週期 ； 多階層供應鏈 ； 系統模擬 ； 存貨策略

並列摘要

The establishment of inventory policy will affect an enterprise’s operation directly. Under the uncertainty of market demand, lack of inventory stock tends to result in loss on sales. Especially for the products with short lifecycles, once the peak demand period has been missed, the products’ value for being sold on the market will lose.
In this study, system simulation was adopted in the construction of a four-echelon supply chain system comprising suppliers, manufacturers, logistics centers, and retailers respectively. The exploration was undertaken, aimed at the inventory policies for better patterns of product life cycles with demand centered on early stage, middle stage or final stage. The main policies that had been taken into account mainly were RQ and TS, as well as the mixed policy of RQ or TS respectively for the upstream and the downstream. Finally, the Sensitivity Analysis was performed in this study, aimed at the three kinds of demand patterns for the products with different product lifecycles.
The research findings indicated: 1. The RQ policy had lower average holding quantity, but had higher shortage quantity. When the changes in demand were greater, the order quantity could not be modified timely via the RQ policy, and hence running out of stock easily.
2. The TS policy had lower average shortage quantity, but had higher holding quantity. When the quantity demanded was fewer than the inventory, the accumulation of inventory tended to occur.
3. In terms of Sensitivity Analysis, it was mainly used for exploring whether the changes in cost would vary the selection of best policy or not. Through simulation experiments, the findings showed that both holding cost and shortage cost would cause influence on the system’s implementation performance in different settings of system parameters. Therefore, in order to select the best inventory policy, the PSR graphic analysis was utilized, to find out the best inventory policy for each demand pattern under the setting of cost parameter.

並列關鍵字

System Simulation ； Product Lifecycle ； Multi-Stage Supply Chain ； Inventory Policies

參考文獻

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