Department of Computer Science, State University of New York at Albany, LI67A, 1400 Washington Avenue, Albany, NY 12222. e-mail: kapur@cs.albany.edu;Department of Computer Science, LIFIA–IMAG–CNRS, 46, avenue Felix Viallet, 38031 Grenoble Cedex, France. e-mail: Dongming.Wang@imag.fr