Keyphrases
- database
- user queries
- query processing
- query expansion
- response time
- data sources
- relevance feedback
- data sets
- query formulation
- query evaluation
- keywords
- keyword search
- complex queries
- original query
- object retrieval
- boolean queries
- data structure
- database systems
- user defined
- vector space
- range queries
- learning algorithm
- databases
- aggregate queries