Affiliation: | a Laboratoire Jacques-Louis Lions, Université Pierre et Marie Curie, BP 187, 75252 Paris Cedex 05, France b Division of Applied Mathematics, Brown University, 182 George Street, Providence, RI 02912, USA c Applied Mathematics and Systems Laboratory, Ecole Centrale Paris, Grande Voie des Vignes, 92295 Chatenay Malabry Cedex, France |