中文摘要：

供货商在订购量达到一定水平时，一般会为订购者提供免运费服务，以达到促销商品的目的．结合这一实际情况，在多阶段易腐品库存问题中引入运费因素，应用集成专家意见的在线序列预测算法研究该问题的竞争性订购策略．基于静态专家意见构建在线订购策略：并证明该策略能够实现与最优专家意见相当的累积收益．数值算例进一步说明策略具有较强的竞争性能及免运费的最小订购量对策略竞争性能的影响．

英文摘要：

The suppliers usually provide free shipping when order quantities reach a certain level. Considering this, this paper introduces shipping into the multi-period perishable inventory problem. Online sequential prediction algorithm of aggregating expert advices is used to study the competitive ordering strategies. Based on stationary expert advices, the online ordering strategy is built. Moreover, the conclusion that the cumulative gain of the online ordering strategy is as large as that of the best expert advice is proved. Numerical examples are further presented to show the great competitive performance of the proposed online strategy and the impact of the minimum ordering quantity of free shipping on a strategy＇s competitive performance.