1. Department of Mechanical and Aerospace Engineering , Sapienza University , Via Eudossiana 18, 00184 Roma
2. Institute for System Analysis and Computer Science “Antonio Ruberti” (IASI-CNR) , Piazzale A. Moro, 7 00185 Roma - Italy
3. Department of Basic and Applied Sciences for Engineering , Sapienza University , Via Antonio Scarpa 16, 00161 Roma
4. Department of Economics , Roma Tre University , via Silvio D’Amico 77, 00145 Rome , Italy