Department of Computer Science, Stony Brook University, Stony Brook, NY 11794-4400 USA. sajjad@cs.sunysb.edu|Department of Computer Science, Stony Brook University, Stony Brook, NY 11794-4400 USA. sajjad@cs.sunysb.edu|Department of Computer Science, Stony Brook University, Stony Brook, NY 11794-4400 USA. sajjad@cs.sunysb.edu