Extracting date/time expressions in super‐function based Japanese–English machine translation

Super‐function based machine translation (SFBMT), which is a type of example‐based machine translation, has a feature which makes it possible to expand the coverage of examples by changing nouns into variables. However, there have been problems extracting entire date/time expressions containing parts‐of‐speech other than nouns, because only nouns/numbers were changed into variables. We describe a method of extracting date/time expressions for SFBMT. SFBMT uses noun determination rules to extract nouns and a bilingual dictionary to obtain the correspondence of the extracted nouns between the source and the target languages. In this method, we add a rule to extract date/time expressions and then extract date/time expressions from a Japanese–English bilingual corpus. The evaluation results shows that the precision of this method for Japanese sentences is 96.7%, with a recall of 98.2%, and the precision for English sentences is 94.7%, with a recall of 92.7%. © 2011 Wiley Periodicals, Inc. Electron Comm Jpn, 94(4): 44–54, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/ecj.10262