1. Concordia Institute for Information Systems Engineering, Concordia University, 1515 Ste-Catherine Street West, EV. 7.640, Montreal, H3G 2W1, Quebec, Canada
2. Interactive Systems, Department of Computer and Cognitive Science, Faculty of Engineering, University of Duisburg-Essen, 47057 Duisburg, North Rhine-Westphalia, Germany
3. Department of Electrical, Electronics and Systems Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor, Malaysia
4. Department of Computer Science, Toulouse 1 University and IRIT Laboratory, 2 rue Doyen Gabriel Marty, 31042 Toulouse Cedex, France