Abstract: Rough set based clustering has been applied widely in soft clustering since proposed,but the threshhold is oft en given subjectively,fails to consider the characteristics of the data set itself. hhis study based on shadowed sets opti mization theory gave an objective thereshold selection method, and applied it to rough fuzzy GMeans clustering algo rithm. Artificial data and UCI data experimental results show the effectiveness of the proposed method.

Key words: Shadowed sets,Rough clustering,Rough-fuzzy clustering