Abstract: The amelioration items ordering problem has not caused enough attention of the scholars. This paper establishes the inventory model of not-allowable shortages and allowable shortages for ameliorating items with non-instantaneous replenishment, and analyzes the correlation between the amelioration rate and the replenishment cycle, various parameters of cost. The results show that the amelioration rate is negatively related with the replenishment cycle and the storage cost per unit time, and is positively related with the amelioration rate and the order cost per unit time and the amelioration cost per unit time and the shortage cost per unit time and the total cost per unit time. Moreover, the paper compares not-allowable shortages model with allowable shortages model about the total cost per unit time, and analyzes the effects of various parameters to the difference of the total cost per unit time of two inventory models. The results show that the difference of the total cost per unit time is positively related with the amelioration rate and the replenishment rate and the order cost per time and the unit storage cost and the unit amelioration cost, and is positively related with the unit shortage cost, and exists the correlation with the demand rate dependent on the ratio relationship of the replenishment rate and the demand rate.

Key words: ameliorating items, inventory, non-instantaneous replenishment, amelioration rate

摘要： 改良品的订货问题一直没有引起足够的重视。分别建立持续补货模式下不允许缺货与允许缺货的改良品库存模型，并分析改良率与补货周期、各种费用参数的相关关系，研究表明：改良率与补货周期、单位时间存储费用呈负相关关系，与单位时间订货费用、单位时间改良费用、单位时间缺货费用、单位时间总费用呈正相关关系。同时，对不允许缺货与允许缺货的改良品库存模型单位时间总费用进行比较，并分析库存模型各参数对两种库存模型单位时间总费用差值的影响方式，研究表明：单位时间总费用差值与改良率、补充速率、单次订货费用、单位存储费用、单位改良费用呈正相关关系，与单位缺货费用成呈负相关关系，与需求速率的相关关系取决于补充速率与需求速率的大小关系。

关键词: 改良品, 库存, 持续补货, 改良率