هماهنگی زنجیره تامین با یک تولید کننده و چند خرده فروش رقیب تحت تقاضای همزمان و اختلالات هزینه

This paper develops a coordination mechanism for a supply chain consisting of one manufacturer and n Cournot competing retailers when the production cost and demands are simultaneously disrupted. This differs from traditional supply chain coordination models under a static case and the case with only demand or cost disruption. The coordination mechanism with revenue sharing is considered, and the effects of production cost and demand disruptions on revenue sharing contract are discussed to investigate the optimal strategies of players with disruptions. The penalty cost is introduced explicitly to obtain the production deviation cost caused by the disruptions. In this study, it is obtained that the coordination contract considering the production deviation cost differs from that without disruption. Besides that, the disruptions may affect the order quantities, wholesale prices as well as revenue sharing contract. Then, the optimal strategies for different disruption levels under the centralized decision-making mode are proposed. Concerning the decentralized mode, the improved revenue sharing contract can be used to coordinate the decentralized decision-making supply chain effectively. Finally, the theoretical results are illustrated by conducting some numerical examples.

With the development of technology and globalization of the economy, the ways that firms compete with each other have become competition in supply chains. Supply chain coordination has emerged as a focused opportunity in recent years. Generally, the conventional research on supply chain coordination focused on the decision making under normal environment, where the demand was deterministic and known, the manufacturer had perfect information about the market, and the operational costs could be excluded from the analysis. However, after the production and sell plan have been settled down, the environment is often disrupted by some unexpected haphazard events, such as terrorism, earthquake, SARS epidemic, financial crisis, labor strikes, raw material shortage, new tax or tariff policy, machine breakdown, and so on. The disruption caused by these unexpected haphazard events has made the members of supply chain aware of the need for active disruption management and focus on whether and how to promise the originally planned coordination scheme valid in the new disrupted environment. Disruption events can affect the performance of a supply chain significantly. These disruptions may destroy facilities and cause that the supply chain cannot be coordinated any more. Therefore, it is meaningful to know how the supply chain can still be coordinated under different levels of disruptions. Handling unexpected disruptions in an efficient and effective way is becoming increasingly important to the success of supply chain management. While the conventional study on supply chain coordination management has developed a static coordination mechanism under a deterministic environment with a known market demand and production cost (Cachon, 2003). In contrast to many traditional studies on the design of supply chain coordination scheme, this paper will address another two aspects of the problem: how disruptions affect the coordination scheme and how to coordinate the supply chain after disruptions. In particular, this paper focuses on both production cost and demands disruptions simultaneously. Generally speaking, production cost disruption is defined as the production cost changes from its estimated value used to design the original coordination scheme. Production cost disruption can occur in various forms at every stage of the production process with different consequences (Xu et al., 2006), for example, raw material prices and transportation costs change, certain equipments fail, and interest rates fluctuate. As such, different solutions are needed to deal with different situations. Practically, unexpected changes of the market demands are very common. For instance, the outbreak of earthquake may cause a large sudden demand for tent; the epidemic of mad cow disease reduces the demand for beef consumption; the execution of new environment legislations can affect the demand of some electrical and electronic products. These cost and demand disruptions have great influence on consumers, retailers, wholesalers, and manufacturers in the entire supply chain. Therefore, new models and effective coordination mechanisms for supply chain coordination are required to handle the disruptions. In this paper, the production cost and demand disruptions are considered in a supply chain with a single manufacturer and n retailers competing in a Cournot market. The particular purpose of the study is to coordinate the disrupted supply chain, especially regarding how the supply chain can be coordinated under production cost and demand disruptions for the manufacturer; and the effects of the production cost and demand disruptions on supply chain coordination with revenue sharing between the manufacturer and the retailers will be investigated. To the best of our knowledge, such a case is considered the first time in this paper. The decision process is expressed as follows. First, the manufacturer makes an initial production plan before the selling season based on a market forecasting. When the selling season arrives, the real market demands and production cost may be found to be different from the forecasted one. Thus, the manufacturer has to adjust the production plan, which will usually cause deviation cost. Consequently, the manufacturer must decide how to adjust the production plan and how to design a new revenue sharing contract, by means of which the manufacturer can induce the retailers to order the proper quantity of products and maximize the profit of the whole supply chain system. So far, there is no research on coordination mechanism for supply chain that consists of a manufacture and n competing retailers in terms of dealing with the simultaneous cost and demands disruptions. The rest of the paper is organized as follows. The related literature is reviewed in Section 2. Section 3 introduces the basic coordination model when n retailers competing in a Cournot market without any disruption. Section 4 studies the coordination of a centralized supply chain with revenue sharing contract in which the manufacturer bears the deviation cost when the demand for every retailer and production cost for manufacturer are disrupted simultaneously. In Section 5, the coordination of a decentralized supply chain with improved revenue sharing contract under both cost and demand disruptions is investigated in detail. The analytical results are illustrated by numerical examples in Section 6. Finally, this paper is summarized in Section 7.

In this paper, we have developed the revenue sharing coordination contract of a supply chain with one manufacturer and n Cournot competing retailers when demand and production cost are disrupted simultaneously. The influences of the demands and cost disruptions on optimal decisions and coordination are analyzed comprehensively. In particular, when the cost and demand disruptions occur simultaneously, if the degree of disruptions are within a certain range, the order and supply plans do not need to change, and only the revenue sharing fraction for the retailers should be changed; if the degree of disruptions exceeds the range, both the plans and the revenue sharing fraction should be changed for the possible coordination of the supply chain. We clearly show that if the manufacturer is able to adjust his revenue sharing contract according to the demands and cost disruptions in a timely way, the supply chain can achieve optimal profit and realize arbitrary allocation of optimal supply chain profit. Furthermore, the revenue sharing contract has demonstrated a certain degree of robustness, and it is optimal for the supply chain to keep the original coordination mechanism if the variation of disruptions is sufficiently small. There are several extensions of this work that could be considered for future research. It would be meaningful to introduce other contracts to coordinate a multi-retailers or multi-suppliers supply chain under disruptions. Another interesting aspect for future research is to consider supply chain disruption management under asymmetric information.