1. School of Software Engineering, South China University of Technology, Guangdong, China
2. Department of Computer Science and Engineering, The Chinese University of Hong Kong and Department of Sociology, The Chinese University of Hong Kong, Hong Kong SAR, China
3. Department of Computer Science, National University of Singapore, Singapore
4. School of Software Engineering, South China University of Technology and Key Laboratory of Big Data and Intelligent Robot (South China University of Technology), Ministry of Education, Guangzhou, Guangdong, China