Keyphrases
- question answering
- information retrieval
- passage retrieval
- natural language processing
- qa systems
- question answering systems
- open domain
- question classification
- natural language questions
- qa clef
- natural language
- test collection
- open domain question answering
- information extraction
- semantic roles
- cross language
- retrieval effectiveness
- search engine
- neural network
- biomedical information retrieval
- trec web
- data sets