1. Department of Computer, Control and Management Engineering, Sapienza University of Rome, 00185 Roma, Italy
2. Institute for Systems Analysis and Computer Science, Italian National Research Council, 00185 Roma, Italy
3. Department of Psychology, Sapienza University of Rome, 00185 Roma, Italy
4. Department of Computational Intelligence, Czestochowa University of Technology, 42-201 Czestochowa, Poland