A hybrid approach for feature reduction

In this thesis, currently available feature selection and dimension reduction methods are analyzed on three different datasets. Particular emphasis is given to filtering-based feature selection methods, which are popular in machine learning area due to their speed. In addition, a linear generalization of the features is obtained by applying dimension reduction in case the scores of the features are close to each other. The feature selection methods that are examined in this thesis evaluate features individually by ignoring correlation between them. At this stage, features marked as redundant are accepted completely irrelevant. Hence, in this thesis, a hybrid feature reduction approach is proposed. In this approach, unchosen features have also opportunity to be involved in classification and clustering by providing a linear projection. Hence, with this approach both the most relevant features selected by feature selection algorithm and projection of unchosen features are utilized. The results obtained in terms of f-measurement show that, besides selecting the best feature subset consisting of top-n features, giving a perfect-fit chance to unchosen features may lead to satisfactory classification results.