1. Department of Industrial Engineering, University of Florence, 50121 Florence, Italy
2. CEMMPRE, Department of Mechanical Engineering, University of Coimbra, 3030-788 Coimbra, Portugal
3. LIDA-ESAD.CR, Polytechnic University of Leiria, 2500-321 Caldas da Rainha, Portugal
4. UnIRE, ISEL, Polytechnic University of Lisbon, 1959-007 Lisbon, Portugal