The traditional way of procurement, using long-term contract and capacity reservation, is competing with the escalating global spot market. Considering the variability of the spot prices, the flexibility of combined sourcing can be used to benefit from occasional low short-term spot price levels...

We consider a perishable inventory system with bonus service for certain customers. The maximum inventory level is S. The ordering policy is (0, S) policy and the lead time is zero. The life time of each items is assumed to be exponential. Arrivals of customers follow a Poisson process with...