Preprint version. Published in International ACH/ALLC Conference Proceedings: Victoria, Canada, June 1, 2005.
NOTE: At the time of publication, the author Alex Dekhtyar was not yet affiliated with Cal Poly.
This is the author's version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. The definitive version was published in International ACH/ALLC Conference Proceedings.