
6 Spectral Feature Selection for Data Mining
tion by removing these irrelevant and redundant features. To achieve this, a
feature evaluation criterion is used with a search strategy to identify the rel-
evant features. And a selection matrix W is used to filter the original data
set and generate a reduced data set containing only the relevant features.
1
Unlike feature selection, feature extraction achieves dimensionality reduction
by combining the original features with a weight matrix W
0
to generate a
smaller set of new features.
2
In the combination process, the irrelevant and
redundant features usually receive zero or very small coefficients, therefore ...