Dipartimento di Elettronica e Informazione Politecnico di Milano e-mail: mara.tanelli@polimi.itpostal address: piazza Leonardo da Vinci 32, 20133 Milano, Italyphysical address: via Ponzio 34/5 (how to reach on http://www.dei.polimi.it) phone +39.02-2399-3621 fax +39.02-2399-3412