Plenary Lecture

Plenary Lecture

On Robust Fuzzy Clustering and Validity Indexes

Professor Miin-Shen Yang
Department of Applied Mathematics
Chung Yuan Christian University
Chung-Li 32023, Taiwan

Abstract: Cluster analysis is a method for finding clusters of a data set with the most similarity within the same cluster and the most dissimilarity between different clusters. It is unsupervised learning in pattern recognition. Since Zadeh [1] proposed fuzzy sets that introduced the idea of partial memberships described by the membership functions, fuzzy clustering has been widely studied and applied in a variety of substantive areas (see [2-5]). In fuzzy clustering, the FCM algorithm and its variations are well known and the most used in various applications. We know that the robustness is important for clustering (see [6]) However, the robustness for these FCM and various extended fuzzy clustering algorithms still needs for further study. In this talk, we shall focus the robustness for these fuzzy clustering algorithms. We use the function of M-estimate to analyze the robustness for fuzzy clustering algorithms and then propose their improvements. On the other hand, cluster validity indexes can be used to evaluate the fitness of data partitions produced by a fuzzy clustering algorithm (see [7-9]). However, the values of validity indexes may be heavily influenced by noise and outliers. In the literature, there is little discussion about the robustness of cluster validity indexes. In this talk, we also analyze the robustness of a validity index using the function of M-estimate. We then improve most fuzzy cluster validity indexes so that they will be more robust for noise and outliers. Some comparative examples with numerical and real data sets will be presented.

Brief Biography of the Speaker:
Miin-Shen Yang received the BS degree in mathematics from the Chung Yuan Christian University, Chungli, Taiwan, in 1977, the MS degree in applied mathematics from the National Chiao-Tung University, Hsinchu, Taiwan, in 1980, and the PhD degree in statistics from the University of South Carolina, Columbia, USA, in 1989.
In 1989, he joined the faculty of the Department of Mathematics in the Chung Yuan Christian University as an Associate Professor, where, since 1994, he has been a Professor. From 1997 to 1998, he was a Visiting Professor with the Department of Industrial Engineering, University of Washington, Seattle. During 2001-2005, he was the Chairman of the Department of Applied Mathematics in the Chung Yuan Christian University. His current research interests include applications of statistics, fuzzy clustering, neural fuzzy systems, pattern recognition and machine learning.
Dr. Yang is an Associate Editor of the IEEE Transactions on Fuzzy Systems, and an Associate Editor of the Applied Computational Intelligence and Soft Computing. He was recently awarded with 2008 Outstanding Associate Editor of IEEE Transactions on Fuzzy Systems, IEEE, and 2009 Outstanding Research Professor of Chung Yuan Christian University.




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