1. Institute of Information Science and the Beijing Key Laboratory of Advanced Information Science and Network Technology, Beijing Jiaotong University, Beijing, China
2. School of Computer Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore
3. Institute of High Performance Computing, A*STAR, #16-16 Connexis, Singapore
4. School of Computer Science and Technology and the Key Laboratory of Big Data Mining and Knowledge Management, University of Chinese Academy of Sciences, Beijing, China
5. Department of Computer Science, City University of Hong Kong, Hong Kong, SAR, China