1. Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, United States of America, 19104 (e-mail: luizf@seas.upenn.edu)
2. Electrical Engineering and Computer Science, University of Pennsylvania, St. Louis, MO, United States of America, 63141 (e-mail: amice@seas.upenn.edu)
3. Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, United States of America, 19104 (e-mail: aribeiro@seas.upenn.edu)