1. Department of Electrical, Computer, and Systems Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
2. Hilti Group, Feldkircherstrasse 100, Postfach 333, Schaan, Liechtenstein
3. Department of Electrical and Computer Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
4. Department of Information Technology, Uppsala University, Uppsala, Sweden