1. Postdoctoral Research Fellow, Dept. of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139.
2. Esther and Harold E. Edgerton Associate Professor, Dept. of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139.
3. Professor of Engineering Mechanics, Ecole Nationale des Ponts et Chaussées, LMSGC (LCPC-ENPC-CNRS UMR113), 77455 Marne-la-Vallée, France.