1. Faculty of Engineering, University of Toyama, Toyama-shi 930-8555, Japan
2. Faculty of Electrical Engineering and Computer Science, Ningbo University, Ningbo, Zhejiang 315211, China
3. Department of Computer Science & Technology, Beijing University of Civil Engineering and Architecture, Beijing 100044, China
4. School of Information, Renmin University of China, Beijing, China
5. Faculty of Electrical, Information and Communication Engineering, Kanazawa University, Kanazawa, Ishikawa 9201192, Japan