A Semi-Supervised Approach to Improve Classification of Infrequent Discourse Relations Using Feature Vector Extension Hugo Hernault author Danushka Bollegala author Mitsuru Ishizuka author 2010-10 text Proceedings of the 2010 Conference on Empirical Methods in Natural Language Processing Hang Li editor Lluís Màrquez editor Association for Computational Linguistics Cambridge, MA conference publication hernault-etal-2010-semi https://aclanthology.org/D10-1039/ 2010-10 399 409