考虑相关采购提前期的成本服务均衡模型及订货批量决策

A Cost Service Equilibrium Model and Order Quantity Decision Considering Correlated Procurement Lead Time

异常事件可能导致供应链中断或订单延迟,由此形成的异常采购提前期(procurement lead time,PLT)往往比正常的PLT要长。为了应对异常状态,企业需要权衡成本和服务水平以制定最优的订货策略。较高水平的订货批量会降低订货次数,形成稳健的订货策略;较低水平的订货批量可以形成灵活的订货策略。本研究将PLTs相关性定义为异常与正常PLTs差异乘数项的均值,基于两个相关PLTs构建零售商库存决策的成本服务均衡模型,研究订货批量决策。研究结果表明,当周期服务水平较高时,PLTs相关性变化并不会影响企业的订货策略;当周期服务水平小于某一值时,PLTs相关性增大,企业倾向于较高的订货批量,从而形成稳健的订货策略。同时,PLT波动对订货批量影响存在多个服务水平阈值,在不同的服务水平范围内,企业可采取的最佳订货策略不同。这个发现与独立PLTs假设中,PLT波动对订货批量影响只有一个服务水平阈值有明显区别。随着PLT波动增大,企业会采取与独立PLTs条件下不同的对策。

Abnormal events may cause supply chain disruptions or order delays,with the result that an abnormal,procurement lead time(PLT)is usually longer than a normal one.Enterprises need to balance the cost and service level to develop the optimal ordering strategy to deal with abnormal events.A higher level of order quantity can reduce the number of orders and form a robust ordering strategy;a lower level of order quantity can form a flexible ordering strategy.The correlation of PLTs is defined as the mean of the differential multiplier terms between abnormal and normal PLTs.Based on the two correlated PLTs,a cost service equilibrium model is established for retailer inventory decisions to study the decision-making of order batches.Results show that when the cycle service level is high,PLTs correlation does not affect the ordering strategy of an enterprise;when the cycle service level is lower than a certain value,enterprises tend to order higher quantity,as PLTs correlation increases,so as to form a robust ordering strategy.Simultaneously,there are multiple service level thresholds for the impact of PLT fluctuations on order batch quantity.In different service level ranges,enterprises can adopt different optimal ordering strategies.This finding is significantly different from that only one service level threshold for the impact of PLT fluctuations on order quantity in the independent PLT hypotheses.As PLT fluctuations increase,enterprises may adopt different strategies from those with independent PLT hypotheses.