Affiliation: | 1. Dept. Matemàtica Aplicada III, ETSECCPB and CRNE , Universitat Politècnica de Catalunya , Jordi Girona 1-3, 08034 Barcelona, Spain a.serra@upc.edu;3. Department of Engineering , University of Liverpool , Brownlow Hill, Liverpool L69 3GH, UK;4. Computer Science and Mathematics Division , Oak Ridge National Laboratory , P.O. Box 2008, Oak Ridge, TN 37831-6138, USA |