[1] Department of Computer Engineering, Bogaziçi University, Bebek, Istanbul,34342, Turkey
[2] Delft University of Technology, Faculty of Engineering, Mathematics, and Computer Science, Mekelweg 4, Delft,2628CD, Netherlands
[3] Idiap Research Institute, Rue Marconi 19, Martigny,CH-1920, Switzerland
[4] Queen Mary University of London, School of Electronic Engineering and Computer Science, Mile End Road, London,E1 4NS, United Kingdom
[5] Department of Computer Science, University of California, Santa Barbara,CA,93110, United States