1. School of Management, Northwestern Polytechnical University, 710072 Xi’an, China;
2. Department of Mathematics, Simon Fraser University Surrey, Surrey, British Columbia V3T 0A3, Canada;
3. Department of Civil Engineering and Applied Mechanics, McGill University, Montreal, Quebec H3A 0G4, Canada;
4. School of Software and Communication Engineering, Jiangxi University of Finance and Economics, 330032 Nanchang, China;
5. School of Computer Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China