1. CNRS, Centrale Lille, Institut Mines-Télécom, UMR 9189 CRIStAL, University of Lille, F-59000 Lille, France
2. IMT Nord Europe, Institut Mines-Télécom, Centre for Digital Systems, F-59000 Lille, France
3. Department of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia, 41100 Modena, Italy
4. Department of Computer Science and Engineering, University of Bologna, 47521 Cesena, Italy
5. Department of Engineering and Architecture, University of Parma, 43121 Parma, Italy
6. Department of Education and Humanities, University of Modena and Reggio Emilia, 42121 Reggio Emilia, Italy
7. Media Integration and Communication Center, University of Florence, 50100 Florence, Italy
8. Dipartimento di Ingegneria dell’Informazione e Scienze Matematiche, University of Siena, 53100 Siena, Italy
9. Department of Computer Science, Aalto University, 02130 Espoo, Finland