Affiliation: | (1) COPPE, Prog. Eng. Sistemas, Universidade Federal do Rio de Janeiro, Cidade Universitária, C.T., Sala H319, Rio de Janeiro, RJ, 21945-970, Brazil, E-mail: esperanc@lcg.ufrj.br , BR;(2) Computer Science Department and Center for Automation Research and the Institute for Advanced Computer Science, University of Maryland at College Park, College Park, MD 20742, USA, E-mail: hjs@umiacs.umd.edu, US |