1. Key Laboratory for Ubiquitous Network and Service Software of Liaoning Province, School of Software, Dalian University of Technology, Dalian, China
2. Amazon, Atlanta, GA, USA
3. Department of Communication Engineering, Institute of Information Science Technology, Dalian Maritime University, Dalian, China
4. School of Computing Technologies, RMIT University, Melbourne, VIC, Australia
5. Research Institute of Artificial Intelligence, Zhejiang Lab, Hangzhou, China
6. IBM T. J. Watson Research Center, Hawthorne, NY, USA