Jiaxin Zhong is a postdoctoral researcher at University of Technology Sydney, Australia. Xiaojun Qiu is a Professor at Nanjing University, China. He is a Fellow of the Audio Engineering Society and the International Institute of Acoustics and Vibration. He is author of An Introduction to Virtual Sound Barriers, and co-author of Active Control of Noise and Vibration, 2nd edition, also published by CRC Press.