1. Artificial and Mechanical Intelligence, Istituto Italiano di Tecnologia, Genoa, Italy.
2. iCub Tech Facility, Istituto Italiano di Tecnologia, Genoa, Italy.
3. School of Computer Science, University of Manchester, Manchester, UK.
4. Department of Computer, Control, and Management Engineering, Sapienza Università di Roma, Rome, Italy.
5. Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA, USA.
6. Department of Medicine, Epidemiology, Occupational and Environmental Hygiene, Istituto Nazionale Assicurazione Infortuni sul Lavoro (INAIL), Rome, Italy.