Manufacturing systems with machine vacations, arbitrary topology and finite buffers

We consider a manufacturing system with finite buffer and arbitrary topolog y where a machine takes a vacation (i.e, is unavailable for processing due to the processing of secondary jobs or maintenance of machines) of random d uration every time the machine becomes idle. To this end, we develop an app roximation (analytical) methodology to calculate the throughput of the syst em using queueing networks together with decomposition, isolation and expan sion methodologies. The methodology was tested rigorously covering a large experimental region. We used orthogonal arrays to design the experiments in order to keep the number of experiments manageable. The results obtained u sing the approximation methodology were compared to simulation results. The t-tests carried out to investigate the differences between tbe two results showed that the proposed methodology is very accurate as well as robust. ( C) 1999 Elsevier Science B.V. All rights reserved.