Adaptive boosting for spatial functions with unstable driving attributes

Abstract

Combining multiple global models (e.g. back-propagation based neural networks) is an effective technique for improving classification accuracy by reducing a variance through manipulating training data distributions. Standard combining methods do not improve local classifiers (e.g. k-nearest neighbors) due to their low sensitivity to data perturbation. Here, we propose an adaptive attribute boosting technique to coalesce multiple local classifiers each using different relevant attribute information. In addition, a modification of boosting method is developed for heterogeneous spatial databases with unstable driving attributes by drawing spatial blocks of data at each boosting round. To reduce the computational costs of k-nearest neighbor (k-NN) classifiers, a novel fast k-NN algorithm is designed. The adaptive attribute boosting applied to real life spatial data and artificial spatial data show observable improvements in prediction accuracy for both local and global classifiers when unstable driving attributes are present in the data. The “spatial” variant of boosting applied to the same data sets resulted in highly significant improvements for the k-NN classifier, making it competitive to boosted neural networks.