1. Division of Science, Engineering and Health Studies, College of Professional and Continuing Education, The Hong Kong Polytechnic University, Hong Kong
2. Division of Business and Hospitality Management, College of Professional and Continuing Education, The Hong Kong Polytechnic University, Hong Kong
3. Department of Computer Science, University of St Andrews, St. Andrews KY16 9AJ, UK
4. College of Automation & College of Artificial Intelligence, Nanjing University of Posts and Telecommunication, Nanjing 210023, China