Tracking RDF Graph Provenance using RDF Molecules Li

Tracking RDF Graph Provenance using RDF Molecules Li Ding, Tim Finin, Yun Peng and Anupam Joshi University of Maryland, Baltimore County The Semantic Web knowledge onion Paulo Pinheiro da Silva and Deborah L. Mc. Guinness Stanford University The role of RDF molecule in tracking provenance RDF document level? Low recall: G 2, G 3 missed! RDF triple level? Low precision: G 4 got matched! Hence RDF Molecule is needed. Lossless RDF graph decompositions An RDF graph decomposition has three elements • W, the background ontology • d(G, W), a function that decomposes an RDF graph G into sub-graphs Ĝ = {G 1, . . . , Gn } using W • m(Ĝ, W), a function that merges all Ĝ's elements into a unified RDF graph G' using W. It is lossless iff G G = m(d(G, W) We identified three types of lossless RDF decompositions: 1. Naive decomposition • blank nodes connect triples • G 1 =>(t 1) and (t 2, t 3, t 4, t 5). 2. Functional decomposition • use functional dependency semantics • (W is empty) G 1 => (t 1) and (t 2, t 3, t 4, t 5). • (W asserts foaf: mbox is IFP) G 1=> (t 1), (t 2, t 5), (t 3, t 5), (t 4, t 5) 3. Heuristic decomposition • use extend functional dependency • (W asserts foaf: first. Name + foaf: surname together functionally decide a person instance) G 1=> (t 1), (t 2, t 3, t 4), (t 3, t 4, t 5) RDF molecule and its applications An RDF molecule of an RDF graph G is the finest, lossless sub-graph of G given a lossless RDF graph decomposition (W, d, m). • lossless - it can be used to restore graph G w/o adding new triples • finest - it cannot be further decomposed into lossless sub-graphs Tracking Web provenance with Swoogle Given an RDF graph, we decompose it into RDF molecules and track its provenance over 680 K online RDF documents indexed by Swoogle. Evaluating trustworthiness of aggregated FOAF profile With the provenance tracking service provided by Swoogle, we may further compute trust to each piece of fused FOAF profile. Finding additional (partial) explanations in Inference Web Given an expression encoded as an RDF graph, we may search for proofs whose conclusions imply corresponding molecules, and then generate additional (partial) explanations to the expression. Partial research support was provided by DARPA contract F 30602 -00 -0591 and by NSF by awards NSF-ITR-IIS-0326460 and NSF-ITR-IDM-0219649.