We constructed a Japanese opinion extraction system for Japanese newspaper articles using a machinelearning method for the system. We used opinionannotated articles as learning data for the machinelearning method. The system extracts opinionated sentences from newspaper articles, and specifies opinion holders and opinion polarities of the extracted sentences. The system also evaluates whether o...

Opinion analysis is an important research topic in recent years. However, there are no common methods to create evaluation corpora. This paper introduces a method for developing opinion corpora involving multiple annotators. The characteristics of the created corpus are discussed, and the methodologies to select more consistent testing collections and their corresponding gold standards are prop...