Systems Engineering and Computer Science Program, COPPE, Federal University of Rio de Janeiro, Caixa Postal 68511, 21941-972 Rio de Janeiro, Brazil. paulo@pcarvalho.com|Systems Engineering and Computer Science Program, COPPE, Federal University of Rio de Janeiro, Caixa Postal 68511, 21941-972 Rio de Janeiro, Brazil. paulo@pcarvalho.com|Systems Engineering and Computer Science Program, COPPE, Federal University of Rio de Janeiro, Caixa Postal 68511, 21941-972 Rio de Janeiro, Brazil. paulo@pcarvalho.com|Systems Engineering and Computer Science Program, COPPE, Federal University of Rio de Janeiro, Caixa Postal 68511, 21941-972 Rio de Janeiro, Brazil. paulo@pcarvalho.com|Systems Engineering and Computer Science Program, COPPE, Federal University of Rio de Janeiro, Caixa Postal 68511, 21941-972 Rio de Janeiro, Brazil. paulo@pcarvalho.com|Systems Engineering and Computer Science Program, COPPE, Federal University of Rio de Janeiro, Caixa Postal 68511, 21941-972 Rio de Janeiro, Brazil. paulo@pcarvalho.com|Systems Engineering and Computer Science Program, COPPE, Federal University of Rio de Janeiro, Caixa Postal 68511, 21941-972 Rio de Janeiro, Brazil. paulo@pcarvalho.com