Nawwaf Kharma,
Faten Hussein, Rabab Ward
Feature weighting is
the general case of feature selection, and hence should perform better
than feature selection, at least in some situations. The initial purpose
of this study was to test the validity of this hypothesis within the
context of character recognition systems. However, we ended up carrying
out two sets of studies, which in turn produced some unexpected but
justified results. The first set compares the performance of Genetic
Algorithm (GA)-based feature selection to GA-based feature weighting,
under various conditions. The second set of studies evaluates the
performance of the better method (which turned out to be feature
selection) in terms of optimal performance and time. The results of
these studies show that (a) feature set selection prior to
classification is important for k-nearest neighbour classifiers, in the
presence of redundant or irrelevant features; and (b) that GAs are
effective methods for feature selection. However, their scalability to
highly-dimensional problems, in practice, is still an open problem.
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