1. Faculty of Applied Sciences, Macao Polytechnic University, Macao SAR, China
2. Department of Computer Science and Engineering—DISI, University of Bologna, 47521 Cesena, Italy
3. Centre for Continuing Education, Macao Polytechnic University, Macao SAR, China
4. Autonomous Robotics Research Center, Technology Innovation Institute (TII), Abu Dhabi P.O. Box 9639, United Arab Emirates
5. Department of Computer Science, University of California, Los Angeles, CA 90095, USA