1. Applied Mathematics II Department, Universitat Politecnica de Catalunya, Jordi Girona 1-3, Barcelona 08034, Spain
2. Automatic Control and Computer Engineering Department, Universitat Politecnica de Catalunya, Jordi Girona 1-3, Barcelona 08034, Spain
3. Dipartimento di Elettronica, Politecnico di Torino, Corso Duca degli Abruzzi, 24 Torino 10129, Italy
4. Pathology Department, Sant Pau Hospital, Autonomous University of Barcelona, Sant Antoni Maria Claret, 167 Barcelona 08025, Spain