1. Jiangsu Key Laboratory of 3-D Printing Equipment and Manufacturing, School of Electrical and Automation Engineering, Nanjing Normal University, Nanjing, China
2. Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Macau, Macau, China
3. Department of Electrical, Electronic, and Computer Engineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, U.K.