ISSN:
1572-9338
Keywords:
Automated manufacturing
;
computerized manufacturing
;
flexible manufacturing systems
;
manufacturing systems
;
measures of congestion
;
queuing formulae
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mathematics
,
Economics
Notes:
Abstract This paper calls attention to two of the more successful queuing approximation formulae — one by Kramer and one by Marchal. The analytic solution of a range of single server Erlang cases is compared to the two approximation formulae. Then a family of H2/M/1 cases is similarly considered. Maximum errors are seen to be about three percent. The Kramer formula seems to be better when the interarrival coefficient of variation is less than 0.66 and the Marchal formula is better for larger interarrival coefficients of variation. Finally, a multiserver refinement function (the ratio of G/G/1 results to M/M/1 results) is proposed to scale M/M/s as an approximation for G/G/s. In most of these multiple channel cases, the maximum error is less than six percent. The last section of this paper presents a simple, representative FMS. It is modelled as an open queuing network. Then the approximation procedure is applied node by node to illustrate the estimation of system performance measures such as machine utilizations and throughput.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02024743
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