Minimum Inventory Variability Dispatching Policies - MIVP®

This paper illustrates the use of discrete event stochastic simulation modeling to compare two scheduling (dispatching) policies for machines in a factory when a machine becomes available for processing. The two policies are first-in-first-out (FIFO) and Minimum Inventory Variability Policies® (MIVP®), both control the items in the queue (buffers) in front of the machine or resource ^8,9,10,11®. The simulation model is run with FIFO for each queue for 100 days to establish a baseline set of data. This baseline cycle time and work-in-progress (WIP) data are collected for comparison to MIVP®. The only change between the model runs is that the queues in the model are switched to run the rule set of MIVP®. With discrete event simulation modeling, the user can play "what if" scenarios without expended a lot of capital ^{4,5,8,9,10,11,19,20}®. The results from simulation give the user an additional input in making decisions. Examples of such a simulator use include the analysis of machine utilization, queue statistics, mean cycle time and mean WIP and production throughput, etc. This analysis can serve to push the bottleneck capacity to its limit, setup and test scheduling rules and preventive maintenance schedules, and determine personnel (operator) availability requirements. Thus, a good simulator allows for the investigation of complex "what-if" scenarios at a minimal cost, high speed, and without disturbing the normal production.