In table 1, page 5 of the published version on IJCNLP04: 180 million should be 1.8 million 2500 million should be 25 million 52000 million should be 520 million The first paragraph of section 5 "Experiment": PIII 1G MHz CPU should be PIII 1G Hz CPU The electrical version on this site has been corrected. Sorry for inconvenience. Zhang Le April 10, 2004