1. Answering Cross-Source Keyword Queries Over Biological Data Sources
Fan Wang
Gagan Agrawal
Ohio State University

2. Motivation Many biological data sources are deep web
Only the query interface, and not the contents, on the surface web
Easy mechanism needed for finding this information
Approach: simple keyword interface
Need ontology and query planning

3. Our Contribution: SEEDEEP System
Discover data source metadata
Generate query plans for search
Fault Tolerance mechanism
Query caching mechanism

4. Query Planning Problem
Ordinary query format
Entity keywords, attribute keywords, comparison predicates
Standard select-project-join SQL query style
Formulation
Sub-graph set cover problem, NP-hard
Target data source
subgraph, can have disconnected components
which nodes cover what terms
the size should be minimal, our cost model
This problem is NP hard
we have node and edge ranking functions
Starting data source