Abstract:
In information retrieval and natural language processing (NLP), question answering (QA) is the task of automatically answering a question posed in natural language. To find the answer to a question, a QA computer program may use either a pre-structured database or a collection of natural language documents (a text corpus such as the World Wide Web or some local collection). QA research attempts to deal with a wide range of question types including: fact, list, definition, How, Why, hypothetical, semantically constrained, and cross-lingual questions. Search collections vary from small local document collections, to internal organization documents, to compiled newswire reports, to the World Wide Web. QA is regarded as requiring more complex natural language processing (NLP) techniques than other types of information retrieval such as document retrieval, thus natural language search engines are sometimes regarded as the next step beyond current search engines.