[1] Univ Lyon, CNRS, Lab Ampere, Ecole Cent Lyon, F-69134 Ecully, France
[2] Univ Lyon, CNRS, Inst Camille Jordan, Ecole Cent Lyon, F-69134 Ecully, France
[3] INRIA, Team NACHOS, F-06902 Sophia Antipolis, France
[4] Univ Limoges, CNRS, XLIM, F-87060 Limoges, France
[5] Univ Toulouse, CNRS, LAPLACE, F-31071 Toulouse, France