Keyphrases
- information retrieval
- tree structure
- information retrieval systems
- search engine
- information filtering
- text mining
- document retrieval
- tree models
- language modeling
- retrieval effectiveness
- retrieval model
- language model
- information extraction
- index structure
- question answering
- test collection
- query expansion
- hierarchical structure
- text retrieval
- database systems
- r tree
- clustering algorithm
- vector space model
- multimedia
- language processing
- binary tree
- data mining