1. Coordinated Science Laboratory and Department of Electrical and Computer Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois, USA;,
2. Laboratory for Information and Decision Systems and Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
3. Current affiliation: Department of Electrical and Computer Engineering and Institute for Systems Research, University of Maryland, College Park, Maryland, USA;
4. School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA;
5. Department of Aeronautics and Astronautics, University of Washington, Seattle, Washington, USA;
6. Department of Electrical and Computer Engineering, University of Washington, Seattle, Washington, USA;