Keyphrases
- retrieval model
- language model
- document retrieval
- information retrieval systems
- language modeling
- test collection
- information retrieval
- retrieval effectiveness
- vector space
- query expansion
- text retrieval
- vector space model
- retrieval systems
- european space agency
- retrieval framework
- relevance feedback
- user queries
- statistical language models
- databases
- improvements in retrieval effectiveness
- retrieval functions
- n gram
- probabilistic model
- sentence retrieval
- data sets
- search engine
- feature selection
- pattern recognition
- query terms
- data analysis
- relevant documents
- database