Active Learning by Labeling Features Gregory Druck author Burr Settles author Andrew McCallum author 2009-08 text Proceedings of the 2009 Conference on Empirical Methods in Natural Language Processing Philipp Koehn editor Rada Mihalcea editor Association for Computational Linguistics Singapore conference publication druck-etal-2009-active https://aclanthology.org/D09-1009/ 2009-08 81 90