1. CINTECX, Universidade de Vigo, Rúa Maxwell s/n, 36310 Vigo, Spain
2. Universidade de Vigo, Industrial Engineering School, Rúa Maxwell s/n, 36310 Vigo, Spain
3. GECAD–Knowledge Engineering and Decision Support Research Center, Polytechnic of Porto, School of Engineering, Rúa Dr. António Bernardino de Almeida, 431, 4200-072 Porto, Portugal