1. Lecturer, Faculty of Science and Technology, State Key Laboratory of Internet of Things for Smart City, Univ. of Macau, Macao 999078, China; Academic Visitor, Dept. of Engineering Science, Univ. of Oxford, Oxford OX1 2JD, UK.
2. Professor, Faculty of Science and Technology, State Key Laboratory of Internet of Things for Smart City, Univ. of Macau, Macao 999078, China (corresponding author).