1. Key Laboratory for Ubiquitous Network and Service Software of Liaoning Province, and the School of Software Technology, Dalian University of Technology, Dalian, China
2. School of Software Technology, Dalian University of Technology, Dalian, China
3. Department of Information Systems and Cyber Security and the Department of Electrical and Computer Engineering, University of Texas at San Antonio, San Antonio, TX, USA
4. Guangxi Key Laboratory of Trusted Software, Guilin University of Electronic Technology, Guilin, China