Keyphrases
- lower bound
- upper bound
- wide range
- response time
- relevance feedback
- query processing
- range queries
- user queries
- database
- query evaluation
- database queries
- query formulation
- worst case
- data structure
- query expansion
- constant factor
- objective function
- retrieval systems
- complex queries
- sufficiently accurate
- np hard
- query terms
- user interaction
- data objects
- branch and bound algorithm
- data sources
- retrieval method
- relational databases
- optimal solution
- keywords