1. School of Technology and Management, Computer Science and Communication Research Centre, Polytechnic Institute of Leiria, Leiria, Portugal
2. School of Technology and Management, Computer Science and Communication Research Centre, Polytechnic Institute of Leiria, Leiria, Portugal & TEMA - Centre for Mechanical Technology and Automation, University of Aveiro, Aveiro, Portugal
3. University of Vigo, Ourense, Spain