1. Department of Intelligent Systems, Jožef Stefan Institute, Jamova 39, Slovenia
2. Department of Electrical Engineering, Chalmers University of Technology, Gothenburg, 41296, Sweden
3. Philips Research, Eindhoven, The Netherlands
4. Polytechnical School, Catholic University of Murcia, Campus de Los Jerónimos, Murcia, Spain
5. Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, China