Optimal Ordering and Trade Credit Policy for EOQ Model

Trade credit is the most prevailing economic phenomena used by the suppliers for encouraging the retailers to increase their ordering quantity. In this article, an attempt is made to derive a mathematical model to find optimal credit policy and hence ordering quantity to minimize the cost. Even though, credit period is offered by the supplier, both parties (supplier and retailer) sit together to agree upon the permissible credit for settlement of the accounts by the retailer. A numerical example is given to support the analytical arguments.Trade Credit, Optimal ordering quantity, Lot-size

Trade Credit Policies for Supplier, Manufacturer, and Retailer: An Imperfect Production-Inventory System with Rework

In this study, we developed a trade credit policy for a three-layer supply chain consisting of a supplier, a manufacturer and a retailer. We propose an optimal production rate and selling price for the manufacturer and the retailer under an imperfect production system. The suggested coordination policy optimizes the profit of each supply chain member. Two models were formulated for two real-life strategies respectively. The first one is a collaborative (integrated) system and the second one is a Stackelberg leadership system. Both strategies were analyzed for various credit periods, respectively offered by the supplier to the manufacturer, by the manufacturer to the retailer, and by the retailer to the customers, by considering price-sensitive demand and a certain replenishment rate. Finally, we concluded which strategy will be better for inventory management under the given restrictions in the form of propositions. The concavity property for the net profit function was established with respect to the selling price and the production rate, which was also described graphically and analyzed by numerical examples

Trade Credit Policies for Supplier, Manufacturer, and Retailer: An Imperfect Production-Inventory System with Rework

In this study, we developed a trade credit policy for a three-layer supply chain consisting of a supplier, a manufacturer and a retailer. We propose an optimal production rate and selling price for the manufacturer and the retailer under an imperfect production system. The suggested coordination policy optimizes the profit of each supply chain member. Two models were formulated for two real-life strategies respectively. The first one is a collaborative (integrated) system and the second one is a Stackelberg leadership system. Both strategies were analyzed for various credit periods, respectively offered by the supplier to the manufacturer, by the manufacturer to the retailer, and by the retailer to the customers, by considering price-sensitive demand and a certain replenishment rate. Finally, we concluded which strategy will be better for inventory management under the given restrictions in the form of propositions. The concavity property for the net profit function was established with respect to the selling price and the production rate, which was also described graphically and analyzed by numerical examples

Stackcelberg Game Inventory Model With Progressive Permissible Delay of Payment Scheme

Supplier has many schemes to motivate retailer to buy more and of them one is a progressive permissible delay of payment. Instead of analyst from the retailer side alone, in this chapter, we develop the inventory model of supplier and retailer. In reality, some suppliers and retailers cannot have collaboration and they try to optimize their own decision so we develop a Stackelberg Game model. Two models are developed wherein the first model supplier acts as the leader and in the second model, the retailer acts a leader. Since the models are complex, a hybrid Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) is developed to solve the model. A numerical analysis and sensitivity analysis are conducted to get management insights of the model. The results show that a Stackelberg Game model for progressive permissible delay of payment is sensitive in varies values of the first and second delay interest rate if supplier acts as a leader. The retailer gets less inventory cost when he acts as a leader compared to when vendor acts a leader at high interest rate of the first and second delay period

[[alternative]]The Study of Supply Chain Inventory Model with Price-Sensitive Demand and Trade Credit

計畫編號：NSC96-2416-H032-007研究期間：200708~200807研究經費：460,000[[abstract]]在現今競爭性的市場環境，企業已經由獨立決策改變為協同合作來制定策略。為降 低成本及改善服務水準，有效的供應鏈策略必須考慮在供應鏈中不同層級之間的互動關 係。在複雜的供應鏈中，存貨的控制是相當困難的工作，而且對顧客的服務水準及整體 供應鏈系統的成本有顯著的影響。因此，在供應鏈管理（Supply Chain Management, SCM）模式下建立適當的整合存貨模型，如何決定同一供應鏈上合作夥伴的最適庫存/ 訂購策略，使得存貨相關總成本為最小或總利潤為最大，是本研究的主要內容。 本研究為二年期的研究計畫，將在考量商品的需求量隨價格變動(即需求率為銷售 價格的遞減函數)，且允許信用交易(供應商允許零售商延遲付款)下，分別建立適當的 整合存貨模型，以決定供應鏈中供應商與零售商的最適存貨策略。第一年在需求率固 定、且供應商允許零售商延遲付款的情況下，嘗試建立分別以供應商為領導者（零售商 為跟隨者）、零售商為領導者（供應商為跟隨者）及雙方合作的供應鏈存貨模型，並求 出Stackelberg 均衡解。。第二年在市場需求率為零售商銷售價格的遞減函數，且供應商 允許零售商延遲付款的情況下，考量非合作與合作賽局策略，建立並求解供應商與零售 商的最佳存貨決策模式。我們將嘗試利用數學證明最佳解存在的充分且必要條件，接著 建立一個演算法求出使得單位時間總利潤有最大值的最適解。最後，以數值範例說明求 解過程，並對重要的參數值進行敏感性分析。[[sponsorship]]行政院國家科學委員

Inventory Policy for Retail Stores: A Multi-Item EOQ Model Considering Permissible Delay in Payment and Limited Warehouse Capacity

The retail industry such as minimarkets has many products consisting of several types of products that have expiration dates. Their warehouses have limited capacity, making it difficult to make decision about optimum inventory. Most of the suppliers will give permissible delay in payment, that can be used to increase income potential through earned by considering the risk of fines imposed if payments are exceeded and help companies raise capital before generating sales. These three factors must be considered when developing the inventory model. The purpose of this study is to develop a multi-item inventory model by considering perishable or damaged products, permissible delay in payment in limited warehouse. Model development is carried out in 2 stages. The first stage was the development of a multi-item EOQ model by considering product defects and permissible delay in payment. The second stage model is by adding a capacity constraint factor to the model.  The results obtained are getting the optimal order quantity by considering the number of product types, product damage factors, late payments in limited warehouses, the best ordering policy can be found, and it is known that the total inventory costs to changes in parameters are good and sensitive to changes in percentage, interest percentage, payment allowances, and warehouse capacity through sensitivity tests

Three-echelon supply chain delivery policy with trade credit consideration

In recent years, collaboration in supply chain approach widely discussed in the literature; but most have dealt with the two-echelon systems. This study focuses on the just-in-time delivery policy of three-echelon supply chain by collaborative approach, where any of the information from the supply chain is available to all the subsystems involved; manufacturer, distribution center and retailer. In the first part of the study a simple model has been developed for a three-echelon supply system that consists of a single manufacturer, a single distribution center and a single retailer. The other part of the study extends this model by considering a upstream integrated delivery supply chain system consisting of a single manufacturer, multiple distribution centers and multiple retailers. In both cases the retailer enjoys a permissible delay in payment. The joint annual cost of the supply chain is obtained by summing the annual relevant costs at all the subsystems. Using the convex property of the cost function, the optimum values of the decision values are initially obtained that minimizes the total cost. Then, these values are adjusted according to feasibility criteria of the credit conditions and other constraints using an algorithm. A numerical example illustrating the solution reveals that total supply chain cost is less by the presented collaborative approach compared to typical delivery policy. A sensitivity analysis also showed the robustness of the new model. This model considers lot-splitting and deferred payment simultaneously. That has not been studied for three-echelon system before. Future extension of this study involves assumption of random demand with cross-transfer delivery, unequal cycle time, shortage consideration, etc