1. Department of Mechanical Engineering; National Taiwan University of Science and Technology; 43, Sec. 4, Keelung Rd.; Taipei; 106; Taiwan
2. Centre for Robotics Research; King's College London; Strand; London; WC2R 2LS; UK
3. Department of Urology; Guy's and St Thomas' Hospitals NHS Foundation Trust; Guy's Hospital, St. Thomas Street; London; SE1 9RT; UK