1. School of Software, and Key Laboratory for Ubiquitous Network and Service Software of Liaoning Province, Dalian University of Technology, Dalian, China
2. School of Information Science and Technology, Dalian Maritime University, Dalian, China
3. School of Software, and Key Laboratory for Ubiquitous Network and Service Software of Liaoning Province, Dalian Key Laboratory of Artificial Intelligence, Dalian University of Technology, Dalian, China