An EOQ model for inventory cost depending on storage time and shortage deteriorating items

Inventory costs are supposed to be stable in most of the researches on inventory.Taking the change rate in inventory costs as the function for the storage time,the paper develops economic order quantity models with the demand rate as a polynomial function of the retailer's current inventory level.Moreover,it works out the conditions for the models to be only,whole and the best when shortage is allowed and belated,illustrating the influence by the change in inventory costs on optimal ordering policies in inventory syestem.At last,some numerical examples are presented to illustrate the application of the model.