1. Department of Biophysical and Electronic Engineering, University of Genoa, Via Opera Pia 11a, 16145 Genoa, Italy
2. Computer Vision & Graphics, Image Processing Department, Heinrich-Hertz-Institute Berlin, Fraunhofer-Institute for Telecommunications, 10587 Berlin, Germany
3. R&D Department, Exent Technologies Ltd., 25 Bazel Street, P.O. Box 2645, Petach Tikva 49125, Israel
4. Converging Networks Laboratory, VTT Technical Research Centre of Finland, 90571 Oulu, Finland
5. Department of Psychology, Goldsmiths, University of London, New Cross, London SE14 6N, UK
6. Research Unit 6, Research Academic Computer Technology Institute, N. Kazantzaki, Panepistimioupoli, 26504 Rion, Greece
7. Computer Engineering and Informatics Department, University of Patras, 26500 Patras, Greece
8. Software Architectures and Platforms Department, VTT Technical Research Centre of Finland, 02044 VTT, Espoo, Finland