کنترل موجودی در زنجیره تامین دو رده بندی شده دو کاناله با راه اندازی تولید و تحویل

This paper considers a two-echelon dual-channel supply chain model with setup of production and delivery and develops a new inventory control policy for the supply chain. Previously, a two-echelon supply chain model without setup of production and delivery is considered and a one-for-one inventory control policy is applied to the supply chain. In the inventory control policy, production is stopped when the warehouse inventory reaches the upper limit and is started again immediately after the inventory drops below the limit. Moreover, delivery to the retailer is stopped when the store inventory reaches the upper limit and is started again immediately after the inventory drops below the limit. The total cost that consists of inventory holding costs and lost sales cost is considered, and setup costs are not considered in the total cost. Once setup costs are introduced, the one-for-one inventory control policy is no longer appropriate. Then, this paper develops a new control policy for the two-echelon dual-channel supply chain with setup of production and delivery. As performance measure, the total cost that consists of inventory holding costs, lost sales cost, and production and delivery setup costs is considered, and the total cost calculated on the basis of Markov analysis demonstrates the effectiveness of the proposed control policy.

This paper considers a two-echelon dual-channel supply chain model with setup of production and delivery and develops a new inventory control policy for the supply chain. Recently, in the SCM field, new channels for supply chains have attracted much interest (see for example, Agatz et al., 2008, Chen et al., 2008, Huang and Swaminathan, 2009, Kumar and Ruan, 2006, Tsay and Agrawal, 2004 and Yao and Liu, 2003). Retailers comprise a traditional channel in supply chains. However, since the internet made on-line shopping easy, it has become an important retail channel as well. Dual-channel supply chains are thus becoming more common. In dual-channel supply chains, customers select the channel through which to buy goods, so dual channels mean more shopping choices and potential cost savings to customers. To traditional retailers and manufacturers, however, the implications for their strategic and operational decisions are not clear. Traditional supply chain models are not sufficient for developing insights into the equilibrium performance of such supply chains. Therefore, several models for addressing these issues have been developed. For example, Chiang et al. (2003) considered the design of dual channels in SCM. Lee et al. (2000) and Li (2002) estimated the value of information sharing in two-level supply chains and in a supply chain with horizontal competition. Yue and Liu (2006) considered demand forecast sharing in dual-channel SCM. Although they considered dual-channel SCM, they did not develop a dual-channel supply chain model or inventory control methods. Dumrongsiri et al. (2008) develop a dual-channel supply chain model in which a manufacturer sells the same product to a retailer as well as directly to consumers, and consumers choose which channel to use to buy the product. Their exact analysis led to conditions for dual-channel equilibrium, and further analysis revealed the effects of demand variability on the supply chain structure. They showed that adding a direct channel increases the total profit if adding such a channel is feasible. However, in considering the profit, they did not consider control of inventory in each channel. Inventory control problems with multiple channels have been considered as a two-echelon inventory system with a central warehouse and a number of retailers. There have been many studies of the two-echelon inventory system (see for example, Schwarz, 1973, Schwarz et al., 1985 and Anily and Federgruen, 1990, and recently Levi et al., 2008). The difference between the original two-echelon inventory system and the more recent dual-sales-channel system is direct upstream demand. Axsäter et al. (2001) considered the relationship between the original and recent systems and proposed a technique for handling the direct upstream demand in the original two-echelon inventory system. Their technique obtains an optimal reorder point for a pre-specified order size. Chiang and Monahan (2005) presented a two-echelon dual-channel supply chain model in which stocks are kept at both a manufacturer warehouse and a retail store and applied a one-for-one replenishment policy (Svoronos and Zipkin, 1991) to the supply chain. Under the control policy, production is stopped when the inventory at the warehouse reaches the upper limit and is started again immediately after the inventory drops below the limit. Moreover, delivery to the store is stopped when the inventory at the retailer reaches the upper limit and is started again immediately after the inventory drops below the limit. They defined the total cost as the sum of inventory holding costs and lost sales cost, and they have not considered setup costs. Once setup costs are introduced, their control policy is no longer appropriate. In this paper, we consider a two-echelon dual-channel supply chain model with setup of production and delivery and develop a new inventory control policy for the supply chain. In the supply chain, the product is available through two channels, and customer demand is stochastic. The demand by retail store customers is met with the inventory at the retailer while the demand by internet-customers is met through direct delivery with the inventory at the manufacturer. When a stockout occurs in either channel, customers shift to the other channel with a known probability. The total cost consisting inventory holding costs, lost sales cost, and production and delivery setup costs is considered. Calculation of the total cost using Markov analysis and numerical calculations demonstrated the effectiveness of the proposed control policy. The rest of this paper is organized as follows. In Section 2, a two-echelon dual-channel supply chain model is described defining the model assumptions and the inventory control policy. A Markov chain model and flow balance equations for the previous and proposed policies are described in Section 3. In addition, the performance measures for the policies are formulated. In Section 4, the numerically calculated performance of each policy under various conditions is presented, and the effects of rates and cost parameters are described. Finally, in Section 5, the key points are summarized and future research work is mentioned.

In this paper, we considered a two-echelon dual-channel supply chain model with setup of production and delivery. Previously, the one-for-one inventory control policy has been proposed for a two-echelon dual-channel supply chain model without setup of production and delivery. Once setups are introduced, the one-for-one inventory control policy is no longer appropriate. Then, we proposed a new inventory control policy for the supply chain model. The total cost that consists of inventory holding costs, lost sales cost, and production and delivery setup costs was calculated using Markov analysis, and the numerical calculation showed the effectiveness of the proposed control policy. The proposed policy can reduce the number of setups without increasing so much the inventories at the warehouse and the retailer, and the proposed policy can reduce the total cost under all conditions, especially under conditions where the unit setup costs of production and delivery are significant and customers arrive through both channels. The model assumes Poisson arrivals and Poisson services of production and delivery, which is rather limiting. However, the proposed policy is nevertheless effective and thus applicable to other situations. In this paper, we considered the setup costs only in terms of the number of production and delivery setups and neglected the setup time. Moreover, rather than assuming one-for-one replenishment, we assumed one-by-one production and one-by-one delivery. The production and delivery lot sizes were not considered. Consideration of the setup time and/or lot sizes of production and delivery are left for future work.