Abstract: Optimizing the coordinated service levels of product entry and exit processes is becoming a crucial task for modern manufacturers to improve the efficiency of warehouse service, reduce enterprise logistics cost, and balance the workload of employees. Thus here the queuing processes of both the product entry and exit services are studied, and a two-stage collaborative queuing model is built to assist the optimal configuration of workforces under a control target of waiting time. The model introduces overflow mechanism and tandem-service mechanism to enable the coordination between the two parts of the warehouse service. Three scenarios are modeled, such as, both front and back services have vacancy, busy in the front while vacant at the back service, vacant(or busy)in the front while the back desks are busy. At all these scenarios, this paper describes each state-transition model, the probability of all system states, as well as the system performance measures such as the rate of workforce usage, queue length, waiting time, and the probability that waiting time exceeds any given operational target. A case of manufacturing enterprise warehouse management of finished product is studied to validate the model. The study shows, in comparison with the existing practice of M/M/S queuing system of the enterprise, the two-stage collaborative queuing system with an overflow mechanism can effectively improve the service efficiency, reduce the average waiting-time and the internal logistics cost resulted from the imbalanced workload of product entry and exit services. Therefore, applying such a model can become an important practice for enhancing the collaborative management level of enterprise internal logistics, as well as the level of automation.

Key words: logistics management, collaborative queuing model, simulation optimization, warehouse logistics, balanced efficiency

摘要： 优化企业成品出入库协同服务水平、平衡工作负荷,从而提高企业仓储服务效率、降低物流成本,是现代制造企业亟待解决的一个重要的管理细节问题。针对这个问题,本研究以仓储入库和出库两个排队过程为研究对象,建立出入库等待时间溢出情景下的两级排队协同服务模型,分析了在排队等待时间控制目标下,出入库员工优化配置方案。该模型引入溢出和串联两个协同服务机制,分三种情景即前方与后方服务台都有空闲,前方繁忙与后方空闲,前方空闲(或繁忙)与后方繁忙,建立了各情景下的系统状态转移方程,求解系统状态的概率,并进而推算出反映系统表现的各项指标,如员工使用率,队列长度,等待时间,以及等待时间超过溢出界值的概率。用制造企业成品出入库管理案例进行验证分析,对企业目前采用的M/M/S出入库排队系统与两级排队协同服务系统进行了数值计算对比。结果表明后者能有效提升出入库服务效率,减少出入库排队系统平均等待时间,降低由于入库和出库两个服务过程效率不均衡而产生的企业内部物流成本,是提升企业内部物流协同管理水平的一个重要方法。其应用可以服务于仓储出入库协同管理的信息化与自动化水平的提高。

关键词: 物流管理, 协同排队模型, 仿真优化, 仓储物流, 效率均衡