1. State Key Laboratory of Virtual Reality Technology and Systems, School of Computer Science and Engineering, Beihang University, Beijing, China
2. State Key Laboratory of Virtual Reality Technology and Systems, School of Computer Science and Engineering, Beihang University & Zhongguancun Laboratory, Beijing, China
3. Shenzhen International Graduate School, Tsinghua University, Beijing, China
4. Jindal School of Management, The University of Texas at Dallas, Richardson, TX, USA