Identifying Web Search Query Reformulation using Concept based Matching Ahmed Hassan author 2013-10 text Proceedings of the 2013 Conference on Empirical Methods in Natural Language Processing David Yarowsky editor Timothy Baldwin editor Anna Korhonen editor Karen Livescu editor Steven Bethard editor Association for Computational Linguistics Seattle, Washington, USA conference publication hassan-2013-identifying https://aclanthology.org/D13-1102/ 2013-10 1000 1010