[1] Washington University, Department of Computer Science and Engineering, Campus Box 1045, One Brookings Drive, St. Louis, MO 63130, United States
[2] Osaka University, Graduate School of Information Science and Technology, 1-5 Yamadaoka, Suita 5650871, Japan
[3] University of Bordeaux, LaBRI, 351 cours de la Libération, 33405 Talence, France