1. CIMA Research Foundation, Via Magliotto 2, 17100 Savona, Italy
2. Department of Engineering Production, Thermoenergetic and Mathematical Models, DIPTEM, University of Genoa, Piazzale Kennedy, Pad. D, 16129 Genoa, Italy
3. Department of Communication Computer and System Sciences, DIST, University of Genoa, Via Opera Pia 13, 16145 Genoa, Italy