Unpacking and Transforming Feature Functions: New Ways to Smooth Phrase Tables Boxing Chen author Roland Kuhn author George Foster author Howard Johnson author 2011-sep 19-23 text Proceedings of Machine Translation Summit XIII: Papers Xiamen, China conference publication chen-etal-2011-unpacking https://aclanthology.org/2011.mtsummit-papers.30/ 2011-sep 19-23