1. School of Computer Science, Carnegie Mellon University, Pittsburgh, PA 15213, USA
2. Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, MD 21218, USA
3. The Robotics Institute, Carnegie Mellon University, Pittsburgh, PA 15213, USA
4. Department of Computational Mathematics, Science, and Engineering, Michigan State University, East Lansing, MI 48824, USA
5. School of Information and Communications Engineering, Xi’an Jiaotong University, Xi’an 710049, China