Tools for DAML-Based Services, Query Answering, and Ontology Development Richard Fikes Deborah McGuinness Sheila McIlraith Gleb Frank Jessica Jenkins Yulin Li Son Tran Honglei Zee Knowledge Systems Laboratory Stanford University www.ksl.stanford.edu 7/19/01

Knowledge Systems Laboratory, Stanford University Project Overview Hot DAML-enabled Web services Hot Reasoning with knowledge represented in DAML DAML language development Member of joint markup language committee Proposed co-chair of W3C WebOnt committee Developed and maintain axiomatic semantics Ontology development environments Chimaera ontology diagnosis tool Translators to enable interoperation with OKBC tools Knowledge Systems Laboratory, Stanford University

Reasoning With DAML Knowledge Bases JTP – a DAML+OIL reasoner Richard Fikes, Gleb Frank, Yulin Li Hybrid reasoning architecture FOL model elimination theorem prover Suite of special purpose reasoners Special purpose DAML+OIL reasoner Efficient storage of RDF statements (triples) Linking of property value sets Based on the axiomatic semantics Implemented in JAVA Knowledge Systems Laboratory, Stanford University

Forward Chaining Infers RDF Statements Assumed assertions (PropertyValue subClassOf Restriction Class) (PropertyValue subClassOf Class rdfs:Class) (Type subClassOf TransitiveProperty) (PropertyValue disjointWith Property rdfs:Class) Forward chaining rules (=> (and (Type ?p TransitiveProperty) (PropertyValue ?p ?x ?y) (PropertyValue ?p ?y ?z)) (PropertyValue ?p ?x ?z)) (=> (and (PropertyValue disjointWith ?cl ?super) (PropertyValue subClassOf ?sub ?super)) (PropertyValue disjointWith ?cl ?sub)) Inferred assertions (PropertyValue subClassOf Restriction rdfs:Class) (PropertyValue disjointWith Property Restriction) Knowledge Systems Laboratory, Stanford University

Forward Chaining Infers Inconsistencies Incorrect portion of translated Wines KB (Type color Property) (PropertyValue maxCardinality color 1) Assumed assertion (PropertyValue domain maxCardinality Restriction) Forward chaining rules (=> (and (PropertyValue domain ?prop ?dm) (PropertyValue ?prop ?fr ?val)) (Type ?fr ?dm)) (=> (and (PropertyValue disjointWith ?c1 ?c2) (Type ?i ?c1) (Type ?i ?c2)) false) Inferences (Type color Restriction) (PropertyValue disjointWith Property Restriction) false  Knowledge Systems Laboratory, Stanford University

Current Challenges for JTP Decrease time for loading knowledge bases Add functionality to backward chainer DAML query language DAML rationale language for explaining query answers More at Friday morning’s breakout session on reasoning Knowledge Systems Laboratory, Stanford University