file - ChaSen - 奈良先端科学技術大学院大学

• Varying annotated expressions so that cannot be acquired rules state descriptiontypes. Therefore it is necessary to gather automatically corpusand to extract features of description types.Some interesting leading studies have been conducted on discourse analysison the Japanese language [51, 95, 170, 175]. However, for actual answer corpusof question-answering in Japanese, previous work is merely found. Maynard [88]explored the structures of answers in Q&A of radio programs and tried to typifythem.4.2.3 Answering proceduresIn recent open domain question-answering, I have seen many studies that respondswith definitions, reasons, and reputations. However, there have beenonly a few leading researches on question-answering that responds with methods.Studies on method retrieval with limited text styles and domains such assearching for patents [32, 122] and cooking recipes [40, 121, 125] have been conductedfor a long time. Questions related to all procedures were addressed by anexpert system [9]. However, only a few studies have been conducted on questionansweringthat responds by searching for methods from an open domain text setsuch as Web texts [5, 135–137, 163]. Additionally, such kind of question-answeringsystem requires a more flexible and more machine-operable approach because ofthe diversity and changeable nature of the information resources. Recently, themost successful approach has been to combine many shallow clues in the textsand occasionally in other linguistic resources. In this approach, the performanceof passage retrieval and categorization is vital for the performance of the entiresystem. In particular, the productiveness of the knowledge of expressions correspondingto each question type, which is principally exploited in retrieval andcategorization, is important. In this sense, the requirements for categorizationin such applications are different from those in previous categorizations. In textcategorization research, feature selection has been discussed [120, 130, 132, 162].However, most of the research dealt with categorization into taxonomy relatedto domain and genre. The features that are used are primarily content words,such as nouns, verbs, and adjectives; functional words and frequent formative50