Hard-fuzzy clustering: A cooperative approach

Data clustering plays an important role in many disciplines, where there is a need to learn the inherent grouping structure of the data in an unsupervised manner. It is well known that no clustering method can adequately handle all sorts of cluster structures and properties (e.g. shape, size, overlapping, and density). Combining multiple clustering methods is an approach to overcome the deficiency of single algorithms and further enhance their performances. Current approaches to multiple clusterings use ensemble clustering to generate aggregated solution from multiple clusterings or using a hybrid cascaded refinement to enhance the end-result clusters produced by a former clustering algorithm(s). A disadvantage of the cluster ensemble is the highly computational load of combing the clustering results especially for large and high dimensional datasets. A drawback of the hybrid approaches is that, one (or more) of the clustering algorithms stays idle until the previous algorithm(s) finishes its clustering. In this paper we propose a Cooperative Hard-Fuzzy Clustering (CHFC) model based on intermediate cooperation between the hard c-means (KM) and fuzzy c-means (FCM) to produce better clustering solutions. Our experimental results over artificial, real, and text documents datasets show that the quality of the clustering solutions obtained from the CHFC model is better than those obtained from both the KM and the FCM and also better than those obtained from hybrid cascaded models.