Hierarchical Clustering for Complex Data

In this paper we introduce a new tree-structured self-organizing neural network called a dynamical growing self-organizing tree (DGSOT). This DGSOT algorithm constructs a hierarchy from top to bottom by division. At each hierarchical level, the DGSOT optimizes the number of clusters, from which the proper hierarchical structure of the underlying data set can be found. We propose a Klevel up distribution (KLD) mechanism. This KLD scheme increases the scope for data distribution in the hierarchy, which allows the data mis-clustered in the early stages to be re-evaluated at a later stage increasing the accuracy of the final clustering result. The DGSOT algorithm, combined with the KLD mechanism, overcomes the drawbacks of traditional hierarchical clustering algorithms (e.g., hierarchical agglomerative clustering). The DGSOT algorithm has been tested on two benchmark data sets including gene expression complex data set and we observe that our algorithm extracts patterns with different levels of abstraction. Furthermore, our approach is useful on recognizing features in complex gene expression data. As a dendrogram, these results can be easily displayed for visualization.