همکاری مدل موجودی در زنجیره تامین
|کد مقاله||سال انتشار||مقاله انگلیسی||ترجمه فارسی||تعداد کلمات|
|20722||2012||8 صفحه PDF||سفارش دهید||محاسبه نشده|
Publisher : Elsevier - Science Direct (الزویر - ساینس دایرکت)
Journal : Economic Modelling, Volume 29, Issue 5, September 2012, Pages 2016–2023
The present article investigates an economic order quantity/ economic production quantity model in three-layer (manufacturer, vendor and retailer) supply chain management. In each stage, the products may undergo non-conforming quality items which have less value in the market. This model maximizes a collaborating expected profit function while production rate, order quantity, number of shipments with equal sizes are decision variables and unit production cost is a function of production rate. Numerical example is illustrated to test the model.
Management Scientists, Researchers as well as Practitioners in manufacturing industries have emphasized to develop production-inventory control problems in supply chain management. A good management is trying always to coordinate the business process and activities of the channel members to improve overall performance of the chain. All steps from supply of raw materials to end customers can be included into a supply chain, involving raw materials supplier, manufacturer, vendor, retailer and finally customers. Better supply chain performance in terms of cost depends on the development and implementation of various strategies such as timely supply, quantity discount, buyback/return policies, quantity flexibility, commitment of purchase quantity, fill rate order size, etc. In competitive marketing environment, every company/management keeps the brand image regarding quality issue with fair prices to capture the market. Consequently, the non-conforming quality (defective) products of each members of the chain are sold at second shop or buyback/return at less price to the market or predecessor member of the chain. In traditional EPQ (economic production quantity) and EOQ (economic order quantity) model, all items are perfect quality(good). It is rational to all enterprises that all items are not perfect, a certain percent of the products are non-conforming quality. These non-conforming quality items may be reworked at a cost or sold at reduced price. For example, in marble, granite, tiles and glass industries; at manufacturer, a certain percent of produced items are defective regarding a particular size, design, etc. These defective items are not used in original purpose but these items are sold at less price for the other purpose such as land/road developing, small size of those items which have less market value. At vendor; a certain percent of good items, supplied from manufacturer to vendor may undergo into nonconforming quality due to transportation and preservation, which have less market value. Similarly, a certain percent of good items, supplied from vendor to retailer may undergo defective due to transportation and preservation, which have less market value at retailer. Generally, in collaborating system, the defective items are sent back at reduced price to the member where it was purchased. This article considers the real-life businesses ( building construction materials such as marbles, tiles, granite and glass, etc.) involving manufacturer, vendor and retailer as members of the chain. Manufacturer produces the nQ batch with variable production rate P while unit production cost is a convex function of the production rate. A certain percent of production rate is non-conforming quality products which are not sold by vendor, but it has a less market value. The vendor purchases Q lot size per order until the inventory level reaches to zero level and the lot size (q) per shipment is delivered to the retailers. The quantity q is delivered from vendor to retailer until the inventory level of retailer reaches at zero level. A certain percent of items of both the vendor and retailer are defective due to transportation and preservation system of them. In their agreement of business partners of the chain, it is mentioned that the defective items at each member to be sent back to the predecessor member at a price and all other price parameters would be fixed for a fixed period. Also, each has to purchase the amount of items at fixed price throughout the contract period as mentioned in the agreement. Finally, an integrated/collaborating expected average profit function is maximized to obtain optimal shipments, order sizes and production rate of the collaborating system. The rest of the paper is organized as follows: Section 2 provides literature survey, Section 3 provides fundamental assumptions and notation. Section 4 describes the formulation of the model. Numerical example is illustrated in Section 5. Section 6 concludes the paper. Section 7 provides references.
نتیجه گیری انگلیسی
Optimal inventory control and quality issues are significant tasks in supply chain management, among other important factors. The optimal inventory control methodologies intend to decrease the SC (supply chain) cost by controlling the inventory in an effective manner so that the members of the chain will not be suffered by surplus as well as shortage of inventory. Most of the industries have shifted from isolated decision-making to a collaborative decision alliance due to increasing competitive pressure, shortened life-cycle products, rigorous quality and quicker response requirements. Collaborating systems in SC are generally based on centralized and decentralized decision-making process.In centralized decision-making process, the whole SC is managed by a unique decision-maker. In this case, the main goal is to maximize(minimize) the total supply chain profit(cost). In the case of decentralized decision-making in a SC while each decision-maker tries to optimize own performance leading to an inefficient system. To avoid this inefficiency, a proper collaborating mechanism should be adopted. Examples of such mechanisms include quantity flexibility contracts, the payback/return policies, transportation agreements and revenue sharing contracts, etc. In this paper, the centralized decision-making process is adapted as a scheme for coordination in SC model where manufacturer, vendor and retailer are the members of the chain. In their agreement, the defective items are buy back to the members from where it is supplied. The probabilities of defective items at each stage follow probability density functions. The production rate at manufacturer is flexible which controls the unit production cost as well as the total cost of the system. The number of shipments of order with equal lot size is different at each sector. This paper focused on the volume flexibility and replenishment lot size problem in a collaborating system where the number of batches, number of transfer order , production rate, order sizes are decision variables rather than an input parameters. These are the new major contribution of the present article compared to the existing literature. The present article can be extended further, considering stochastic demand for manufacturing, supplier and retailer. The rework of the defective items in each stage of the supply chain can be incorporated in future extension of the present article.