자동창고시스템의 성능평가를 위한 M/G/1 대기모형

Abstract

Most of the techniques for the performance estimation of unit-load AS/RS are a static model or computer simulation. Especially, their models have been developed under the assumption that the Storage/Retrieval (S/R) machine performs either single command(SC) or dual cormnand{DC) only. In reality, depending on the operating policy and the status of the system at a particular time, the S/R machine perfonns a SC or a DC, or becomes idle. In order to resolve this weak point, we propose a stochastic model for the performance estimation of unit-load AS/RS by using a M/G/l queueing model with a single server and two queues. Server utilization, expected numbers of waiting storage and retrieval commands and mean time spent in queue and system are found.