Keyphrases
- question answering
- natural language
- natural language processing
- qa clef
- information extraction
- syntactic information
- information retrieval
- passage retrieval
- natural language questions
- named entities
- question classification
- question answering systems
- open domain question answering
- cross language
- artificial intelligence
- relation extraction
- context free grammars
- semantic analysis
- answer extraction
- machine translation
- expert systems
- search engine