1. Department of Computer Science, City University of Hong Kong, Kowloon, Hong Kong
2. DAAI Research Group, Department of Computing and Data Science, School of Computing and Digital Technology, Birmingham City University, Birmingham B4 7XG, UK
3. UTM Big Data Centre, Ibnu Sina Institute for Scientific and Industrial Research, Universiti Teknologi Malaysia, Johor Bahru 81310, Johor, Malaysia
4. College of Computing, Georgia Institute of Technology, Atlanta, GA 30332, USA