1. Georgia Institute of Technology, School of Electrical and Computer Engineering, GT-Lorraine, 57070 Metz, France
2. CNRS, UMI 2958, G T - CNRS, 2 rue Marconi, 57070 Metz, France
3. GT Lorraine, 2 rue Marconi, 57070 Metz, France
4. Institut Lafayette, 2 rue Marconi, 57070 Metz, France