1. a Intelligent Autonomous Systems Group, Technische Universität München, 85748 Garching, Germany
2. b Department of Neural Information Processing, University of Ulm, 89069 Ulm, Germany
3. c Intelligent Autonomous Systems Group, Technische Universität München, 85748 Garching, Germany
4. d Department of Neural Information Processing, University of Ulm, 89069 Ulm, Germany