1. CERI Numerique, IMT Lille Douai, University of Lille, 59500 Douai, France
2. Dip. Ingegneria Dell’ Impresa, University of Rome “Tor Vergata”, 00133 Rome, Italy
3. Department of Computer Science and Engineering (DISI) Alma Mater Studiorum—Universit´ di Bologna, 40126 Bologna, Italy
4. Centre for Intelligent Information Technologies (CETINIA), University Rey Juan Carlos, 28933 Madrid, Spain