1. Department of Computer Science, University of Calgary, 2500 University Dr. NW, Calgary, Canada and University of Munich (LMU), Institut für Informatik, LFE Medieninformatik, Amalienstrasse 17, 80333, Munich, Germany
2. Department of Computer Science, University of Calgary, 2500 University Dr. NW, Calgary, Canada
3. University of Munich (LMU), Institut für Informatik, LFE Medieninformatik, Amalienstrasse 17, 80333, Munich, Germany