整合數量與運輸折扣之機率性存貨模型

Stochastic inventory model with quantity and freight discounts integration

傅科瑜(Fu.KoYu)

指導教授 ： 張宏吉

國立臺中科技大學/商管學群/事業經營研究所/碩士(2008年)

摘要

在供應鏈管理的概念下，整合運輸與存貨控制問題是相當值得探究的議題。以往的存貨管理模式中，若考慮到運輸成本時，通常假設運輸成本由供應商管理，當成單位成本的一部分；或是視為固定訂購成本的一部分，且與運送批量大小無關，使得運輸成本的影響無法完整的反應在管理決策上。本文針對隨機需求環境，考量缺貨時為完全欠撥的情況，建構整合數量折扣與運輸折扣之連續盤查存貨模型，並且建立各種折扣組合類型的求解程序，以求取全年期望總成本為最小之最佳存貨策略。此外，本研究分別在前置時間內需求量服從常態分配與均勻分配之假設下，探討模型之最佳解，並藉由數值範例說明求解的結果、總成本節省的績效，與各參數值變動對訂購量、再訂購點及期望總成本的影響。研究的結果顯示，本文所提出的模型與獨立決策的模型相較，皆具有一定的成本節省效果，其中又以雙全單位折扣型最為顯著。

關鍵字

數量折扣 ； 運輸折扣 ； 連續盤查存貨模型

並列摘要

In supply chain management, transportation and inventory problems are very important. In the traditional inventory models, transportation cost is implicitly assumed being controlled by the supplier, so it is treated as a part of unit cost or included in the ordering cost, which is independent of delivery lot size. Thus, the effect of transportation cost could not reflect on management strategy completely. This study considers the continuous review inventory system with backorders, where various mixed types of freight discounts (all-weight/incremental weight) and quantity discounts (all-units/increment) are incorporated. Also, two special distributions, normal and uniform, are adopted to formulate the stochastic demand during lead time. For each discount policies, we develop solution procedures to find the optimal order quantity and reorder point such that the expected total annual cost is minimized. Furthermore, the results of proposed models are illustrated by numerical experiments, and sensitivity analysis is performed to examine the effect of problem parameters on the optimal policies. Comparing with the results of independent decision model where transportation cost is considered separately, the cost savings can be obtained using the proposed models in this study, and the case of dual all-units discounts has the great effect on cost savings.

並列關鍵字

quantity discounts ； freight discounts ； continuous review inventory model

參考文獻

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