Abstract: An assembly system with two suppliers and one assembler was considered. The demand of complete and assembly products was uncertain, and the products were sold over a single selling season. The operation mechanism of the assembly system under Vendor Managed Inventory (VMI) was discussed. Based on analysis of the model in which the suppliers produced parts only once, a twice production mode was introduced, and the suppliers'optimal inventory decisions were discussed. The results showed that the performance of the supply chain was improved after introduction of a twice production mode. And conclusions were illustrated by a numerical example.

Key words: supply chains, assembly system, vendor managed inventory, twice production mode, Pareto improvement

摘要： 考虑一个由两个供应商和一个装配商所组成的装配系统，装配商所面临的需求是不确定的，并且产品具有季节性销售的特征。研究了供应商管理库存模式下装配系统的运作机制，在分析传统的单次生产模式基础上，引入了两次生产模式。分析了在两次生产模式下，供应商对库存的最优决策。论证了两次生产模式对装配系统性能所产生的积极作用。通过算例对结论进行了说明。

关键词: 供应链, 装配系统, 供应商管理库存, 两次生产模式, Pareto改进