DATE: Wed, Msy 9, 2018
TIME: 1 pm
PLACE: SITE 5084
TITLE: Fast Hoeffding and McDiarmid Drift Detection Methods for Adaptive Learning from Evolving Data Streams
PRESENTER: Ali Pesaranghader
University of Ottawa
ABSTRACT:

Learning from evolving data streams is a challenging task due to the distributional changes in data, i.e., the 'concept drift' phenomenon. Learning algorithms have to adapt themselves to the new distributions for keeping the accuracy of classification high. Drift detection methods, as the main component of adaptive learning algorithms, are responsible for detecting concept drifts, with the least delay, as soon as they appear in data streams. Such methods should also avoid high false positive and false negative rates while the input data are processed. False positive refers to false alarms for a concept drift, whereas false negative means ignoring a real concept drift. False positive entails keeping more resources busy, whereas false negative causes loss in the classification accuracy. Additionally, based on the probably approximately correct (PAC) learning model, a high false positive rate may not let accuracy increase as an insignificant amount of data would be used for training. The drift detection methods should not assume the input data, e.g., prediction results, follow a specific distribution function as the nature of streaming data is dynamic. Finally, an adaptive learning algorithm has to obtain a higher accuracy, compared to a non-adaptive algorithm, to be considered beneficial for a learning task from evolving data streams. To address these challenges, we introduce three kinds of sliding window-based methods, which use Hoeffding's and McDiarmid's inequalities, for detecting drift points in a data stream. We experimentally show that our methods outperform the state-of-the-art.