1. Department of Decision Science, HEC Montréal, Montréal, Québec H3T 2A7, Canada;
2. École de Technologie Supérieure, Montréal, Québec H3C 1K3, Canada;
3. GERAD, Montréal, Québec H3T 1J4, Canada;
4. Department of Mathematics and Industrial Engineering, Polytechnique Montréal, Montréal, Québec H3T 1J4, Canada;
5. CIRRELT, Montréal, Québec H3C 3A7, Canada;
6. Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milano, Italy