On Mar.29, 2007, American Professor Yao Kung, from Electrical Engineering Department, University of California Los Angeles (UCLA), was invited to give a report in our institute. The Seminar was anchored by Director Tian Jing. Deputy Director Zhang Chunhua, Director Assistant Ma Xiaochuan, Director Li Xiaodong of Communication Acoustics Lab, Director Liu Ke of Noise and Vibration Lab attended the seminar.

Dr. Yao received the B.S.E. (the highest honor), M.A. and Ph.D. degrees in electrical engineering all from Princeton University, Princeton, N.J. He was a NAS-NRC Post-Doctoral Research Fellow at the University of California, Berkeley. Presently, he is a Distinguished Professor in the Electrical Engineering Department at UCLA. He is a Life Fellow of IEEE.

His research and professional interests include sensor array system, digital communication theory and system, smart antenna and wireless radio system, digital and array signal and array processing, systolic and VLSI algorithms, architectures and systems, radar system, satellite system, and simulation. He has published over 300 journal and conference papers.

The report Dr. Yao gave us titled "Analysis, Design, Implementation and Applications of Microphone Arrays". In his report, Dr. Yao reviewed three different classes of microphone arrays for various applications. The first array used four uniformly-spaced hearing aid microphones to perform a steerable array based on the maximum-energy criterion. A system implemented with a DSP processor board collected various experimental data in an anechoic chamber and a regular room for hearing aid applications. The second array used randomly distributed microphones to perform wideband beamforming based on a maximum eigenvector array for vehicle detection, localization, and signal enhancement. The third array was based on the Approximate Maximum-Likelihood criterion to estimate single or multiple acoustic sources for near-field localization and far-field direction-of-arrival estimations. This array was able to carry out various beamforming and nulling operations. Several wired wireless experimental arrays have been implemented for various applications. In his report, Dr. Yao presented a great amount of data obtained from the experiments, which made the whole report more vivid and convincing. After the report, Dr. Yao had a warm discussion with the audience.

After the seminar, companied by Director Li Xiaodong, Dr. Yao paid a visit to the reverberation room, sound insulation room, anechoic room and semi-anechoic room of Communication Acoustics Lab. During the visit, Dr. Yao showed great interest in our measuring microphone and the active anti-noise microphone, and had a discussion with Director Li Xiaodong on architecture acoustics and microperforated panel muffler. Dr. Yao highly praised the acoustic equipment devices and research condition in our institute and said he was deeply impressed by this visit.