1. Institute of Electronics and Informatics Engineering of Aveiro (IEETA), University of Aveiro, 3810-193 Aveiro, Portugal
2. School of Health Sciences (ESSUA), University of Aveiro, 3810-193 Aveiro, Portugal
3. Department of Mathematics (DMat), University of Aveiro, 3810-193 Aveiro, Portugal
4. Department of Electrical and Computer Engineering, University of Porto, 4200-465 Porto, Portugal