The Improved Hierarchical Clustering Algorithm by a P System with Active Membranes

In this paper an improved hierarchical clustering algorithm by a P system with active membranes is proposed which provides new ideas and methods for cluster analysis. The membrane system has great parallelism. It could reduce the computational time complexity and is suitable for the clustering problem. Firstly an improved hierarchical algorithm was presented which introduced the K-medoids algorithm. The distance of clusters is defined as the distance between the medoids of these clusters instead of the mean distance between them. Secondly a P system with all the rules to solve the above hierarchical algorithm was constructed. The specific P system is designed for the dissimilarity matrix associated with n objects. The computation of the system can obtain one possible classifications in a non-deterministic way. Through example test, the proposed algorithm is appropriate for cluster analysis. This is a new attempt in applications of membrane system. Key-Words: Clustering algorithm; the hierarchical clustering; K-medoids algorithm; Membrane computing; P System; Membrane system