1 EmoRe Research Group, Department of Mathematics and Computer Science, University of Perugia, Perugia, Italy.
2 Department of Engineering and Architecture, University of Parma, Parma, Italy.
3 Artificial Intelligence and Robotics Research Group, Department of Computer, Control and Management Engineering, La Sapienza University of Rome, Rome, Italy.
4 Department of Computer Science, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China.
5 Department of Computer Science, University of Bari "Aldo Moro", Bari, Italy.
6 ICREA Acadèmia, Department of Philosophy, Universitat Autònoma de Barcelona, Barcelona, Catalonia, Spain.