Keyphrases
- information retrieval
- information retrieval systems
- search engine
- document collections
- learning to rank
- text mining
- language model
- query expansion
- test collection
- artificial intelligence
- question answering
- retrieval systems
- vector space model
- information access
- language modeling
- chinese text
- information extraction
- ir evaluation
- listed companies
- language processing
- information seeking
- learning algorithm
- retrieval model
- neural network
- higher level
- web search
- relevance feedback