I am going to shamelessly quote my own paper here :-) Our INFOCOM paper
(http://www.cs.wisc.edu/~cao/papers/zipf-implications.html)
calculated the alpha value for UC Berkeley traces, DEC Corporate traces,
as well as a few others. The values range from 0.64 to 0.83; the alpha
values are calculated using MatLab's curve-fitting tool, excluding the top
100 documents. They are slightly higher than the NLANR logs. But there
was a paper from last year's WCW conference arguing that as one goes up
the caching hierarchy, the alpha value actually decreases, which matches the
results here.
I think 0.6 is a good choice. If one is really concerned about high memory
hit ratio, I would say go with 0.4, which are below 90% of the data points
on the curve at http://www.ircache.net/Cache/Statistics/Popularity-Index/.
Any thoughts?
Pei
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