1. Realistic Media Research Platform Center, Korea Electronics Technologies Institute, 11 Worldcup buk-ro-54-gil, Mapo-gu, Seoul, 121-835, Republic of Korea
2. Computer Science, University of Illinois at Chicago, 851 S. Morgan, Chicago, IL, 60607, USA
3. HCI Institute, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, PA, 15213, USA