一般化信用交易條件下某些生產存貨模型之研究

A study of some production inventory models under generalized trade credit

黃千修(Chien-Hsiu Huang)

指導教授 ： 歐陽良裕

共同指導教授 ： 楊志德(Chih-Te Yang)

淡江大學/商管學院/管理科學學系博士班/博士(2020年)

https://doi.org/10.6846/TKU.2020.00811

摘要

存貨管理是企業經營者掌握適當物品，在適當的時間，以適當的數量，有效整合上、下游作業流程，賺取最大利潤或付出最少成本的一種經營管理模式。完善的存貨管理需考量許多實務的議題，例如在實際商業交易行為中，供應商為了吸引新顧客上門，或希望零售商增加訂購量，通常會允許買方在收到物品的一段時間後才支付貨款。另外，在進貨物品中，對於物品的完好度或新鮮度而言，假若物品因退化或腐敗而造成缺陷或新鮮度不足，會使需求率下滑。
面對激烈的市場競爭及產銷環境的瞬息變化，企業必須透過供應鏈體系的整合，減少不良品，提高品質，全面提升運作效率。進一步，為了降低物品的不良率，通常供應商會投資資金改善製程或設備，但若所投資的資金過於龐大，供應商便會降低投資意願。從供應鏈管理的角度思考，如果供應鏈成員能協議共同分擔資金投資來共同改善生產製程或設備，不僅可提高供應商的投資意願；當不良率降低到某一水準或以下時，零售商亦可對收到物品進行免檢而節省檢驗成本。
又當生產成本很高或採購金額很大時，供應商會要求零售商預先支付一部分金額作為訂單履約的保障；接著，在零售商收到物品時再支付一部分的購買費用，剩餘的貨款則允許可以無息在一段信用交易期間後才付清。這種一般化的信用交易條件，稱之為預付-現金-信用交易。
本文是在供應商提供信用交易的條件下考慮一些存貨模型。在第二章，我們探討供應商提供二選一信用交易條件下物品中含有不良品並且允許缺貨的供應鏈生產和存貨模型，模型中假設如果零售商每次訂購量超過規定的門檻，則運輸費用全數由供應商自行吸收；否則，由零售商負擔。第三章在供應商提供零售商預付-現金-信用交易條件下，考慮市場需求率同時與零售商存貨水準以及售價有關之退化性物品的存貨問題。其中零售商對其顧客也提供信用交易，並且貨架上物品陳列空間有限制。第四章主要是在供應商提供零售商預付-現金-信用交易付款條件並且零售商也對其顧客提供信用交易的情況下，探討含有不良品的供應鏈生產與存貨模型。其中，物品的不良率可藉由供應商和零售商雙方的共同投資資金加以改善。對以上各章，我們以計量方法建立適當的數學模型，並透過數量分析，分別求得最佳的生產與訂購策略(第二章)；最佳的銷售價格與訂購策略(第三章)，和最佳的投資、生產與訂購策略(第四章)，使得對應的目標函數總利潤有最大值。每章均分別舉例說明其求解過程，並做敏感度分析以瞭解參數值變動對最佳解所造成的影響。最後，第五章則提出本研究的結論及未來的研究方向。

關鍵字

供應鏈 ； 生產與存貨 ； 不良品 ； 退化 ； 預付-現金-信用交易

並列摘要

Inventory management is an operation and management model in which enterprise managers master the right items, at the right time, in the right quantity, and effectively integrate the upstream and downstream operation processes to earn maximum profit or pay minimum cost. To do a good job in inventory management, many practical issues need to be considered. For example, in the actual business transaction, to attract new customers or increase the order quantity, the supplier usually allows the retailer to pay for the goods after a period of time. In addition, if the item is defective or lacks freshness due to deterioration or decay, the demand will decline.
In the face of fierce market competition and rapid changes in the production and marketing environment, enterprises must try to reduce defective products, improve quality, and improve overall operational efficiency through the integration of supply chain systems. However, reducing defective products or improving quality requires investment. If the investment amount is huge, it will reduce the supplier’s willingness invest. Thinking from the perspective of supply chain management, if the members of the supply chain can agree to share the capital investment to improve the production process or equipment, it not only can promote the supplier’s willingness to invest but also can save the retailer’s cost of the goods received without inspection as the proportion of defective products drops to a certain level or below.
When the production cost is high or the purchase amount is large, the supplier will ask the retailer to pay a part of the amount in advance to ensure the order fulfillment; then, he will pay a part of purchase fee as receiving the items, and the remaining payment is allowed to be paid off after a period of credit transaction without interest. This generalized credit transaction procedure is called 'Advance-Cash-Credit payments'.
This dissertation studies some inventory models utilizing the condition that suppliers provide credit transactions. In Chapter 2, it discusses the supply chain production and inventory system where the supplier provides two-part trade credit policy conditions, the goods contain defective products and the shortages are allowed. The proposed model assumes that if the retailer's order quantity exceeds the specified threshold, then all transportation costs are absorbed by the suppliers themselves; otherwise, they are paid by the retailers. Chapter 3 considers the inventory problem of deteriorating items with stock-and price-dependent demand under Advance-Cash-Credit payments. Additionally, the retailer also provides trade credit to its customers, and there is limited space for the display space of items on the shelves. Chapter 4 mainly develops the supply chain production and inventory model with defective products when the supplier provides the retailer Advance-Cash-Credit payments and the retailer also provides trade credit to its customers. In the model, the rate of defective goods can be reduced by the joint investment of both the supplier and retailer. For the above chapters, we establish appropriate mathematical models by measurement method, and obtain the optimal production and ordering strategies (Chapter 2); the optimal pricing and ordering strategies (Chapter 3) and optimal investing, production and ordering strategies (Chapter 4) to maximize the corresponding total profits. Each chapter separately illustrates the solution process and sensitivity analysis to understand the impact of changes of parameters on the optimal solution. Finally, Chapter 5 presents the conclusions and future research directions of this study.

並列關鍵字

supply chain ； production and inventory ； defective products ； deterioration ； Advance-Cash-Credit payments

參考文獻

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