1. School of Software, Northwestern Polytechnical University, Xian, China
2. Department of Math and Computer Science, Brandon University, Brandon, MB, Canada
3. National Engineering Laboratory for Big Data System Computing Technology, Shenzhen University, Shenzhen, P. R. China
4. Department of Electrical Engineering and Computer Science, Embry-Riddle Aeronautical University, Daytona Beach, FL, USA