1. Department of Computer Science, Universitat de València, 46100 Burjassot, Spain
2. Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milano, Italy
3. Institute of Computer Science (ICS), Foundation for Research & Technology-Hellas (FORTH), Heraklion, 70013 Crete, Greece
4. Department of Computer Science, University of Crete, Heraklion, 70013 Crete, Greece
5. Department of Electronic Engineering, Inha University, Incheon 22212, Republic of Korea