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This can be rewritten by factoring e-r from both numerator and denominator, leaving:
0616-01.gif
Observe that for n = 1 (and m = 1):
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For n = 2:
0616-03.gif
and for n = 3:
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For each of the preceding cases:
0616-05.gif
and
0616-06.gif
where
0616-07.gif
Outside the single-server, low-population cases, the asymptotic model is generally consistent with the exact Kobayashi model (error usually less than 10%). It offers the following advantages:
1. It is computationally easier, especially for large n.
2. It is based on M/G/1, not M/M/1, and allows appropriate use of c2 when known or estimated.
Figure 9.14 plots the error between the asymptotic model and the finite population model (both for c2 = 1).
For the remainder of the chapter, we generally use the asymptotic model except in the special cases (n = 1, or n = 2 and c2 = 1) where the exact (M/M/1) result is used.

 
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