1. Research Assistant, Dept. of Management Information Science and Operations Management, Faculty of Economics and Business Administration, Ghent Univ., Tweekerkenstraat 2, 9000 Ghent, Belgium.
2. Full Professor, Dept. of Management Information Science and Operations Management, Faculty of Economics and Business Administration, Ghent Univ., Tweekerkenstraat 2, 9000 Ghent, Belgium (corresponding author).