Extended Self-Organizing Map on Transactional Data

Abstract

In many application domains, transactions are the records of personal activities. Transactions always reveal personal behavior customs, so clustering the transactional data can divide individuals into different segments. Transactional data are often accompanied with a concept hierarchy, which defines the relevancy among all of the possible items in transactional data. However, most of clustering methods in transactional data ignore the existing of the concept hierarchy. Owing to the lack of the relevancy provided by the concept hierarchy, clustering algorithms tend to separate some similar patterns into different clusters. Besides, their clustering results are not easy to be viewed by users. The purpose of this study is to propose an extended SOM model which can handle transactional data accompanied with a concept hierarchy. The new SOM model is named as SetSOM. It can project the transactional data into a two-dimensional map; in the meanwhile, the topological order of the transactional data can be preserved and visualized in the 2-D map. Experiments on synthetic and real datasets were conducted, and the results demonstrated the SetSOM outperforms other SOM models in execution time, and the qualities of visualization, mapping and clustering.