Keyphrases
- question answering
- natural language processing
- information retrieval
- natural language
- question answering systems
- named entities
- question classification
- passage retrieval
- natural language questions
- information extraction
- syntactic information
- learning algorithm
- cross language
- sentence retrieval
- open domain question answering
- qa clef
- relation extraction
- machine learning
- semantic roles
- answer extraction
- answering questions
- answer validation
- information retrieval systems
- qa systems
- probabilistic model