2IBGSOM: interior and irregular boundaries growing self-organizing maps

In this paper, we introduce a new variant of growing self-organizing maps (GSOM) based on Alahakoon´s algorithm for SOM training; so called 2IBGSOM (interior and irregular boundaries growing self-organizing maps). It´s dynamically evolving structure for SOM, which allocates map size and shape during the unsupervised training process. 2IBGSOM starts with a small number of initial nodes and generates new nodes from the boundary and the interior of the network. 2IBGSOM represents the structure of the training data as accurately as possible. Our proposed method was tested on real world databases and showed better performance than the classical SOM and the growing grid (GG) algorithms. Three criteria were used to compare the above algorithms with our proposed method; the quantization error; the topological error and the labeling error to have more accuracy on the produced structure. Results report that 2IBGSOM shows a very good capacity of estimation for the training data based on the three tested factors.