others, one problem with the standard
competitive learning
update scheme 1s that some neurons may
never win the competition as never learn.
A phenomenon of monopoly is a
common problem. A monopoly is
defined as a state in which a small
number of output cells respond to all the
input patterns and the other remaining
cells never respond to any of the input
patterns.
unsupervised
To avoid the state of monopoly,
some networks set the initial synaptic
connection to be random ([18]). Other
modifications, monopoly can be avoided
in several ways by using two other
unsupervised learning paradigms,
Kohonen learning and conscience
learning. Kohonen learning is that the
weights of all neurons in a neighborhood
of the winning neuron are updated and
the size of this neighborhood is
gradually ^ decreased over time.
Conscience learning is that a conscience
is added to frequently winning neurons
to feel "guilty" and reduce their winning
rate.
Numerous ANNs studies have
been performed with discrete, class-
separable data. Classification of remote
sensing satellite data in high dimension
is a challenge for using ANNs technique
because most researches have been
performed on low-dimensional statistical
data, and a few researches have been
performed on high-dimensional artificial
or reality data. Although the study of
neural network techniques for
classifying multispectral and multisource
satellite data is in the beginning stage
and this level of performance of
competitive learning network is not
expected at this research stage, neural
network appears some advantages as
inherently parallel, self-organization,
good generalization to be feasible
classifier for every large multichannel
images, and it can be an alternative
method for land-cover classification by
improving its learning capability.
Reference
1. Ahalt, S. C., Krishnamurthy, A. K,,
Chen,P. and Melton, D. E.; 1990.
Competitive Learning
Algorithms for Vector Quan-
tization, Neural Networks, Vol.
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2. Balakrishnan, P. V., Cooper, M. C.,
Jacob, V. S. and Lewis, P. A;
1993. A Study of the Classific-
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Networks Using Unsupervised
Learning: A Comparison with K-
Means Clustering, Ohio State
University, College of Business,
Working Paper Series, No. 61,
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3. Benediktsson, J. A., Swain, P. H., and
Ersoy, O., K.; 1990. Neural
Network Approaches Versus
Statistical Methods in Classific-
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pp. 540-552.
4. Burke, L. I.; 1991. Introduction to
Artificial Neural Systems for
Pattern Recognition, Computers
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International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B7. Vienna 1996