Keyphrases
- transformation rules
- query processing
- database
- user queries
- response time
- semantically relevant
- semantic meaning
- complex queries
- query expansion
- database queries
- query evaluation
- relevance feedback
- algebraic operations
- query answers
- formal semantics
- model selection
- data sources
- information retrieval systems
- keywords
- co occurrence
- semantically equivalent
- data structure
- retrieval systems
- user interaction
- mixture model
- retrieval method
- query execution
- query formulation
- sparql queries
- probabilistic model
- database systems