1. a ELEDIA Research Group, Department of Information Engineering and Computer Science, University of Trento, Via Sommarive 14, Trento 38050, Italy
2. b ELEDIA Research Group, Department of Information Engineering and Computer Science, University of Trento, Via Sommarive 14, Trento 38050, Italy
3. c ELEDIA Research Group, Department of Information Engineering and Computer Science, University of Trento, Via Sommarive 14, Trento 38050, Italy
4. d ELEDIA Research Group, Department of Information Engineering and Computer Science, University of Trento, Via Sommarive 14, Trento 38050, Italy
5. e ELEDIA Research Group, Department of Information Engineering and Computer Science, University of Trento, Via Sommarive 14, Trento 38050, Italy;, Email: andrea.massa@ing.unitn.it