Institute for Innovation and Technology (IIT) Berlin, Germany.|Center of Excellence: Cognitive Interaction Technology (CITEC), University of Bielefeld, Bielefeld, Germany.|Center of Excellence: Cognitive Interaction Technology (CITEC), University of Bielefeld, Bielefeld, Germany.|Center of Excellence: Cognitive Interaction Technology (CITEC), University of Bielefeld, Bielefeld, Germany.|Center of Excellence: Cognitive Interaction Technology (CITEC), University of Bielefeld, Bielefeld, Germany.