1. Department of Process Engineering, University of Veszprem, P.O. Box 158, H-8201, Hungary, Department of Information Technology and Systems and Control Engineering Laboratory, Delft University of Technology, P.O. Box 5031 2600 GA Delft, The Netherlands, and Instituto Superior and Department of Mechanical Engineering, Technical University of Lisbon, GCAR Avenida Rovisco Pais, 1049-001 Lisboa, Portugal