Topic:
Graph Fourier Transform and Graph Filter (圖形傅立葉轉換和圖形濾波器)

Speaker:
曾建誠 教授
Prof. Chien-Cheng Tseng
國立高雄科技大學電腦與通訊工程系
Dept. of Computer and Communication Engineering, NKUST

Language :
Chinese

Date:
2019/04/12

Time:
14:20~16:20

Location: Delta building R215, NTHU

Abstract:
In recent years, the signal processing on graphs have received great attentions. The conventional regular temporal and spatial signal processing algorithms have been extended to irregular graph signal processing (GSP) algorithms. The applications of GSP include social, economic, sensor, transportation, neural, brain, molecular and biological networks. In this talk, two basic tools in GSP are presented. One is graph Fourier transform, the other is graph filter. Firstly, the graph Laplacian matrix which is the fundamental building block of GSP is described. Secondly, the graph Fourier transforms is defined. The eigenvalues and eigenvectors of graph Laplacian matrix correspond to the frequencies and spectral Fourier basis. The application of missing data recovery of temperature data is used to show the effectiveness of graph Fourier transform. Thirdly, the generalization of the filtering operation in the vertex domain over graphs is studied. The frequency-selective graph filters (low-pass, band-pass and high-pass filters) are defined and designed. Fourthly, an adaptive graph filter based on least mean squared (LMS) algorithm is presented such that the unknown time-varying graph filter can be tracked and identified. Finally, conclusions are made.

Biography:
Chien-Cheng Tseng received his Ph.D. degree from the National Taiwan University in Electrical Engineering in 1994. He was an Associate Research Engineer at Telecommunication Laboratories, Chunghwa Telecom Company, from 1995 to 1997. He was the Professor and Chairman of the Department of Computer and Communication Engineering, National Kaohsiung First University of Science and Technology, from 2006 to 2009. He is currently the Dean of the College of Electrical Engineering and Computer Science, National Kaohsiung University of Science and Technology. He has served an Associate Editor of IEEE Trans. on Circuits and Systems-I: Regular Papers, an Editorial Board Member of IET Signal Processing, and an Editorial Board Member of the EURASIP Signal Processing Journal. His research interests include digital signal processing and digital image processing.