Minimum Bayes Risk based Answer Re-ranking for Question Answering Nan Duan author 2013-08 text Proceedings of the 51st Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers) Hinrich Schuetze editor Pascale Fung editor Massimo Poesio editor Association for Computational Linguistics Sofia, Bulgaria conference publication duan-2013-minimum https://aclanthology.org/P13-2075/ 2013-08 424 428