Modelling flow and jobbing shops as a queueing network for workload control
Modelling flow and jobbing shops as a queueing network for workload control
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DOI：
10.1016/s0925-5273(01)00117-7
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发表时间：
2002-08
影响因子：
12
通讯作者：
A. Haskose;B. Kingsman;D. Worthington
中科院分区：
文献类型：
--
作者：
A. Haskose;B. Kingsman;D. Worthington
工作负载控制是一种生产计划和控制方法，旨在管理制造提前期，而不是将其视为预测问题。它特别适合工业按订单生产领域的分批作业和流水车间。它基于排队论中著名的利特尔公式：到达在系统中花费的时间是系统中的平均数量除以到达率。然而，工作负载控制方法将作业车间视为单个实体，因此忽略了由于竞争作业同时到达工作站从而形成队列而造成的复杂性。本文描述了如何将作业车间环境构建为开放式排队网络。如果工作站超过三四个，则在计算上不可能精确求解模型。描述了工作站三角形配置的精确马尔可夫过程模型的结果。初步结果表明，将每个工作站视为独立的排队系统会导致制造提前期的严重低估，即使对于如此简单的制造系统也是如此。还讨论了一些关于推导精确模型的近似值以覆盖更大系统的初步想法。
Workload control is an approach for production planning and control that attempts to manage manufacturing lead times rather than treat them as a forecasting problem. It is particularly appropriate for jobbing and flow shops in the make-to-order sector of industry. It is based on Little's well known formula in queueing theory that the time an arrival spends in the system is the average number in the system divided by the arrival rate. However, the workload control approach treats the jobbing shop as a single entity and thus ignores the complexities caused by competing jobs arriving at a work station at the same time thus forming queues. This paper describes how the job shop environment may be formulated as an open queueing network. It is computationally impossible to solve the model exactly if there are more than three or four work stations. Results for an exact Markov process model for a triangular configuration of work stations are described. Initial results suggest that treating each work station as an independent queueing system leads to significant under-estimation of the manufacturing lead times, even for such a simple manufacturing system. Some initial ideas on deriving an approximation of the exact model to cover larger systems are also discussed.