连续库存补充策略订货点水平确定方法比较

考虑顾客需求满足一阶自回归和滑动平均即ARMA(1,1)过程情形下,建立连续库存补充策略中的变动订货点水平确定模型,并将此模型与其它两种模型(基于时点需求的模型、传统模型)从理论和仿真角度进行比较分析。理论分析得出,在需求呈正相关且随机误差项平滑系数为正数时,变化订货点水平确定模型得出的安全库存低于根据时点需求得出的安全库存,而高于传统模型得出的安全库存。最后结合具体数例对不同模型情形下的库存成本进行仿真分析,结果表明,变化订货点模型所引起的平均缺货率、平均库存成本均低于其它两种模型,从而验证所提出模型的优越性和有效性。

Comparison of determination approaches of reorder level in a continuous replenishment strategy

Based on a first order autoregressive and moving average (i.e. ARMA(1,1)) demand process, an optimization model of the variable reorder level in a continuous replenishment strategy is developed. A theoretical comparison is conducted to demonstrate that when autocorrelation coefficient and moving average coefficient are positive, the safety stock with a variable reorder level is less than that determined by means of moments of demand, but more than that with traditional reorder point approach. Furthermore, the safety stock level difference between using a variable reorder level and based on moments of demand, as well as that between using a variable reorder level and based on traditional reorder points are increasing in replenishment lead time, demand autocorrelation degree and random error moving average coefficient. At last, a numerical simulation experiment is made to compare the inventory costs with different models. It is shown that the average stockout rate and average inventory cost based on variable reorder level are less than those based on the other two reorder levels.