Identification of Non-referential Zero Pronouns for Korean-English Machine Translation

摘要

The common use of null arguments is one of the most critical issues in pro-drop languages. When translating Korean into other languages, the omitted elements should be replaced with appropriate pronouns to get grammatical target sentences. One of the most important issues when dealing with zero pronouns is to determine the referentiality of zero pronouns. Since, like expletive 'it' in English, omitted elements do not have always explicit referents, it is important to determine whether a zero pronoun is referential or not. In this paper, we focus on identifying non-referential zero pronouns. Since non-referential zero pronouns are likely to occur in similar contexts, referentiality determination in this paper is regarded as the identification of clauses containing non-referential zero pronouns. Our method outperforms the baseline systems using n-grams and bag of words, and achieves the F-measure of 0.51 and 0.78.