1. INRIA Comore, 2004 Route des Lucioles, B.P. 93, 06902 Sophia-Antipolis Cedex, France, (E-mail: )
2. Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge,MA 02139-4307, USA, (E-mail: )
3. Department of Chemical Engineering, University of Santiago de Compostela, rúa Lope Gómez de Marzoa s/n ES-15782 Santiago de Compostela, Spain, (E-mail: )