Keyphrases
- query processing
- response time
- database
- query evaluation
- user queries
- keywords
- data structure
- databases
- relevance feedback
- query expansion
- query formulation
- complex queries
- user defined
- original query
- database queries
- keyword search
- retrieval systems
- search queries
- information retrieval
- heterogeneous databases
- object retrieval
- answering queries
- multiple queries