The first author is partially supported by NSERC grant OGP-0172859, STR-0181014, and DARPA grant MDA972-97-1-0016. The second author is partially supported by NSF grant IRI-9510112, DARPA grant MDA972-97-1-0016, and grants from Intel and Hewlett-Packard. Our thanks are also due to the DIOM implementation team at University of Alberta, especially David Buttler, Yooshin Lee, Kirill Richine, and Wei Tang.