Annotation of Focus for Negation in Japanese Text

Abstract

This paper proposes an annotation scheme for the focus of negation in Japanese text. Negation has a scope, and its focus falls within this scope. The scope of negation is the part of the sentence that is negated. The focus of negation is the part of the scope that is prominently negated. In natural language processing, correct interpretation of negated statements requires precise detection of the focus of negation in the statements. As a foundation for developing a focus detector, we have annotated a part of "Rakuten Travel: User Review Data" and a part of a newspaper subcorpus of the "Balanced Corpus of Contemporary Written Japanese," with our annotation scheme. In this scheme, a negation cue in the text data is linked to the focus by annotation with identifying clues. These clues include focus particles such as "wa" and "shika," and other expressions in the context. We report 1,327 negation cues and the foci in the corpora.