1. INRIA Sophia Antipolis, OPALE Project Team, 2004 Route des Lucioles, 06902 Sophia Antipolis, France
2. University Nice Sophia Antipolis, Mathematics Department, 28 Avenue de Valrose, 06103 Nice Cedex 2, France
3. ArcelorMittal Global R&D, route de St. Leu, 60761 Montataire Cedex, France