Affiliation: | 1. Département d’Informatique, Université Laval, Québec, Québec, Canada G1V 0A6;2. Google Inc., 2400 Bayshore Parkway, Mountain View, CA 94043, USA;3. School of CTI, De Paul University, Chicago, IL 60604-2287, USA;4. School of Computer Science, McGill University, Montréal, Québec, Canada H3A 2A7 |