Using unlabeled data to help supervised learning has become an increasingly attractive methodology and proven to be effective in many applications. This paper applies semi-supervised classification algorithms, based on hidden Markov models (HMMs), to classify sequences. For model-based classification, semisupervised learning amounts to using both labeled and unlabeled data to train model parameters. We examine three different strategies of using labeled and unlabeled data in the model training process. These strategies differ in how and when labeled and unlabeled data contribute in the whole model training process. Our experimental results on synthetic and real EEG time-series show that substantially improved classification accuracy can be achieved by these semi-supervised learning strategies.
Published Date: May 2004
Registration: ISBN 978-1-57735-201-3
Copyright: Published by The AAAI Press, Menlo Park, California.