Affiliation: | (1) Computer Science Department, University of Alabama in Birmingham, 35294 Birmingham, Alabama;(2) Present address: Lawrence Berkeley Laboratory, University of California, MS 50B-3238, 94720 Berkeley, CA;(3) Computer Science Department, University of Southwestern Louisiana, 70504 Lafayette, Louisiana;(4) Present address: IBM T. J. Watson Research Center, P.O. Box 218, 10598 Yorktown Heights, New York |