[1] Rutgers State Univ, Elect & Comp Engn Dept, New Brunswick, NJ 08902 USA
[2] Arizona State Univ, Dept Elect Comp & Energy Engn, Tempe, AZ 85287 USA
[3] Univ Washington, Dept Elect Engn, Seattle, WA 98195 USA
[4] Korea Univ, Dept Comp Sci & Engn, Seoul 136713, South Korea
[5] ETH, Dept Comp Sci, CH-8092 Zurich, Switzerland