1. School of Computer Science and Technology, Nanjing Normal University, Nanjing, Jiangsu 210023, China. wangshuihua@njnu.edu.cn
2. Department of Mechanical Engineering, Sardar Vallabhbhai National Institute of Technology, Ichchanath, Surat-395 007, Gujarat State, India
3. Department of Electrical Engineering, Columbia University, New York, NY 10027, USA
4. Jiangsu Key Laboratory of 3D Printing Equipment and Manufacturing, Nanjing, Jiangsu 210042, China. zhangyudong@njnu.edu.cn
5. W.P. Carey School of Business, Arizona State University, Tempe, AZ 85287, USA
6. School of Electronic Information & Electrical Engineering, Shanghai Jiaotong University, Shanghai 200030, China