1. Laboratoire I3S; University of Nice Sophia Antipolis, CNRS, Les Algorithmes - Bât. Euclide B; 2000 Route des lucioles, B.P. 121-06903 Sophia Antipolis; Cedex; France
2. Gipsa-Lab, Systems Control Department; University Joseph Fourier, CNRS; 961 rue de la Houille Blanche, B.P. 46-38402 Grenoble; Cedex; France