1. NTT Communication Science Laboratories, Atsugi, Kanagawa, Japan
2. FRANKA EMIKA GmbH, Muenchen, Germany
3. School of Electrical Engineering and Computer Science, School of Health and Rehabilitation Sciences, The University of Queensland, St Lucia, QLD, Australia
4. Institute of Intelligent Systems and Robotics, Sorbonne Université, Paris, France
5. UM-CNRS Laboratoire d'Informatique, de Robotique et de Microélectronique de Montpellier (LIRMM), Montpellier, France
6. Imperial College of Science, Technology and Medicine, London, U.K.