Abstract: Industrial symbiosis is an effective way to achieve sustainable production and reduce waste emissions. Unlike traditional emission reduction technologies that focus on reducing waste generation in the production process, it pays more attention to the reuse of waste between different entities or supply chains. From the perspective of operations and supply chain management, also different from the traditional reverse supply chain, which focuses on the recycling of waste or used products in the supply chain, symbiotic supply chain is concerned with the reuse of waste between originally independent supply chains. In a symbiotic supply chain, the core business of the symbiotic supplier is not to provide recycled materials to the manufacturer, but to provide the final product to its end market. This leads to an uncertainty in the supply of recycled materials and thus creates decision-making difficulties for the symbiotic supplier. Additionally, the emergence of symbiotic suppliers has also changed the structure of manufacturers’ supply sides, which brings operational and supply chain management challenges to manufacturers. It is worth considering how to choose between recycled materials and raw materials. Furthermore, designing contracts to coordinate symbiotic supply chains to balance production among all parties and maximize profits for all are an important and complex issue. Differing from the traditional coordination focused on the intra-supply chain, a symbiotic supply chain essentially involves the coordination between two supply chains, and there is little existing research focusing on this coordination issues.
This paper studies the optimal pricing of recycled materials and the optimal production decisions of all parties in a symbiotic supply chain, based on the potential for symbiotic cooperation between two manufacturers, and designs contracts to coordinate the supply chain. First, we construct a symbiotic model consisting of two supply chains that reach symbiotic cooperation, with a symbiotic supplier in a dominant position, a manufacturer in the following position, and the wholesale price of raw materials as an exogenous variable. Second, we concentrate on the production decisions of the manufacturer and symbiotic supplier and the pricing of recycled materials. Finally, a revenue-sharing contract is designed to coordinate the supply chain, and the feasible region of the contract under different conditions, as well as the impact of various parameters on the feasible region, is analyzed.
The results indicate that: 1.When the price sensitivity coefficient faced by the manufacturer is relatively low, there will be a shortage of recycled materials; when this price sensitivity coefficient is moderately increased, supply and demand will reach equilibrium; until this point, the symbiotic supply chain operates in a fully symbiotic mode. When this price sensitivity coefficient further increase, it will lead to an oversupply, at which point a partially symbiotic mode is formed. 2.In the decentralized decision scenario, the manufacturer decides the optimal production quantity according to its conditions. The symbiotic supplier, on the other hand, may not reach the optimal production quantity. 3.Under certain conditions (e.g., manufacturers face a medium price sensitivity factor), symbiotic cooperation may have a disruptive impact on the operation decisions of the symbiotic supplier, i.e., the primary business of the symbiotic supplier shifts from supplying the product for its end market and “incidentally” supplying recycled materials for the manufacturer, to primarily supplying recycled materials for the manufacturer and “incidentally” providing products for the end market. In other words, for the symbiotic supplier, the utilization of recycled materials not only brings additional revenue but also fundamentally changes the operational decision. 4.For the manufacturer, there will be no difference between centralized and decentralized decision-making scenarios only when the manufacturer is faced with a very small price sensitivity factor. For the symbiotic supplier, there will be no difference between the two scenarios when the manufacturer is faced with a very small or a very large price sensitivity factor. In other scenarios, the manufacturer’s final product quantity is smaller than that in the centralized decision-making scenario. 5. Under certain conditions (e.g., the manufacturer is faced with a large price sensitivity factor), a revenue-sharing contract enables the symbiotic supply chain to achieve the desired results in the decentralized decision-making scenario. A revenue-sharing contract is more beneficial to the symbiotic supplier, i.e., it can achieve the coordination effect when the supply of recycled materials exceeds the demand, or otherwise, it cannot.

Key words: symbiotic supply chain, revenue sharing contract, pricing decision, production decision

摘要： 共生供应链上再生材料定价和各方生产决策问题,是共生供应链实践需要解决的核心问题。针对这些问题,构建由两条原本相互独立的供应链因再生材料利用而形成的共生供应链模型,分别对分散和集中决策下的均衡决策问题进行分析,探讨完全共生与部分共生的条件以及各个参数对再生材料定价和双方生产决策的影响。研究发现:在分散决策情景下,制造商面临的价格敏感系数较小时共生供应链达成完全共生模式,当价格敏感系数增大到一定程度后,则达成部分共生模式。比较分散和集中决策发现,当且仅当制造商面临的价格敏感系数非常小时共生供应链无须协调,其他情景下均需协调。最后,设计收入共享契约协调共生供应链以达到帕累托改进,给出了契约可行域并分析了各参数对契约可行域的影响。

关键词: 共生供应链, 收入共享契约, 定价决策, 生产决策