2009 IEEE International Conference on
Systems, Man, and Cybernetics |
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Abstract
An unsupervised competitive learning
algorithm based on the classical k-means clustering algorithm is
proposed. The proposed learning algorithm called the centroid
neural network (CNN) estimates centroids of the related cluster
groups in training date. It is based on the observation that
synaptic vectors converge to the centroids of clusters as learning
proceeds in conventional unsupervised competitive learning
algorithms such as SOM or DCL. The centroid, or conditional
expectation, can minimize the mean-squared error of the vector
quantization. As is the case with SOM or DCL, the synaptic
vectors converge to the centroids of clusters as learning proceeds
in CNN. However, the CNN finds locally optimal synaptic vectors
for each datum presented and consequently converges to the
centroids of clusters much faster than conventional algorithms.
This centroid neural network can be used for generating the
clusters using user data. The data may either image pixels or
tables of information. One of the very advantageous features in
the CNN algorithm is that the CNN does not require a schedule
for learning coefficients. The CNN rather finds its optimal
learning coefficient in each representation of data vectors. The
CNN can also reward and punish by learning coefficients for
winners and losers, respectively. Unlike SOM or DCL, the CNN
also does not require the total number of iteration in advance.