在新兴电子商务环境中，线上与线下服务水平往往影响各自的客户需求，由此产生线上线下需求相互迁移而影响供应链系统的利润。本文考虑供应链O2O系统中客户需求受线上与线下服务影响，分别建立客户需求迁移和不迁移两种情形下，线下门店为品牌商自营门店的集中式服务决策模型，以及线下门店为品牌商加盟门店的分散式服务决策模型；计算集中式决策下使得O2O系统利润最大化的最优服务水平，以及分散式决策下使得品牌商与线下加盟商达到Nash均衡的最优服务水平以及所需条件，并通过算例仿真对所建模型结果进行验证和分析。研究结果表明，在集中式决策下，当且仅当线上或线下一方提供服务时，需求迁移或不迁移两种情形下的供应链O2O系统利润均可达到最优；当线上线下均提供服务时，只有需求不迁移情形可达到O2O系统最优。而分散式决策下，线上或线下单方提供服务及双方均提供服务时，若满足一定条件，需求不迁移和需求迁移两种情形始终存在Nash均衡解。

With the development of mobile internet, the emerging e-commerce O2O (Online to Offline) business strategy with the support of the widespread use of mobile apps and e-transactions has gained significant popularity in the retail industry. As a business strategy, O2O commerce draws potential customers from online channels to physical stores according to offline stores' service level,vice versa. Therefore, some of customers change their buying channel from one to the other when service level of online or offline changes, which is called demand shift. Thus, channel demand will be affected, as well as O2O system's profit.
In this paper, with the consideration of impact of the service levels to demand in both online channel and offline channel, the optimal service decisions in supply chain O2O system are studied. The two kinds of situations are discussed, one situation is that demand does not shift, although affected by the levels of service; the other is that demand shift from one channel to the other with the change of service levels. In each situation, there exist two different decision models, i.e., the centralized and decentralized service decision models of O2O system, respectively. The centralized decision model means the brand supplier provides products to self-own stores; while the decentralized decision model means the brand supplier provides products to its franchise stores. The optimal service strategy of centralized system and decentralized system are investigated, respectively. More specifically, a two-echelon supply chain O2O system with one brand supplier and offline stores is considered. The brand not only sells the product to the offline stores but also sells directly to the end customer through its online stores. For centralized system, the total profit model is established to discuss the optimal service levels to maximize the total profit of the system. Further, similar to the centralized system, for the decentralized system, the profit models of the brand supplier and the offline franchisee are established, respectively. Then, the optimal service levels that make the brand and the franchisee achieve Nash equilibrium are discussed. Accordingly, the condition for Nash equilibrium solution is obtained.
The research results show:1) for the centralized system, when one of online and offline provides services, the O2O system can achieve the optimal no matter demand no shift or not. If both online and offline services are provided, only in the case that the demand is not shift between online and offline, the O2O system can obtain optimal profits. 2) for the decentralized system, whether one of online and offline provides services or both provide services, only if some conditions are met, the O2O system always achieve Nash equilibrium both in demand shift and no shift situation. Finally, a typical clothing brand M in China is taken as an example for numerical analysis. Some parameters are assumed, and the impact of service levels on profits is discussed. Our research is helpful to companies who make optimal service decision as they practice the emerging O2O commerce.