1. Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
2. Institute for Human and Machine Cognition, 40 Alcaniz Street, Pensacola, Florida 32502, USA
3. University of Texas at Austin, 5706 Jeff Davis Ave, Austin, Texas 78756, USA
4. Deutsches Zentrum für Luft und Raumfahrt, Linder Höhe, 51147 Köln, Germany