Enriching OWL with Instance Recognition Semantics for Automated Semantic Annotation Stephen W. Liddle Information Systems Department Yihong Ding & David W. Embley Computer Science Department Brigham Young University, Provo, Utah

2 of 20 6 November 2007 ONISW 2007, Auckland, New Zealand Outline Background Instance recognition semantics Automated semantic annotation OWL-AA: OWL for Automated Annotation Related work Conclusion

3 of 20 6 November 2007 ONISW 2007, Auckland, New Zealand Motivation Big Hairy Audacious Goal: deliver a machine- processable semantic web that will let us build agents to work intelligently on our behalf Realistic Shorter-term Goal: provide automatic semantic annotation machinery that turns ordinary web pages into semantic web pages by adding appropriate metadata Goal of this Paper: Show that we can extend OWL with epistemological declarations that let us use our data extraction engine to provide a solid automatic annotator that works with standard ontologies

4 of 20 6 November 2007 ONISW 2007, Auckland, New Zealand Typical Approach Typical approach to automatic annotation: Use existing data extraction engine to wrap and annotate pages BUT these approaches do not match extracted data with an ontology Main drawback: Post-processing step to map extracted data to the ontology

5 of 20 6 November 2007 ONISW 2007, Auckland, New Zealand Our Approach Our data extraction engine is ontology based and does not need a post-processing alignment step We have demonstrated that our approach works (Ding/Embley/Liddle 2006, LNCS 4185) But our ontology language is not a W3C standard OWL is a standard (W3C recommendation) But lacks sufficient declarative instance- recognition semantics for automatic annotation

6 of 20 6 November 2007 ONISW 2007, Auckland, New Zealand A Solution Extend OWL with declarative instance- recognition semantics Call this OWL for Automated Annotation (OWL-AA) OWL-AA extension is epistemological in nature Ontological definitions should be independent of the form of knowledge representation Epistemological definitions may be sensitive to the form of knowledge representation

7 of 20 6 November 2007 ONISW 2007, Auckland, New Zealand Our Contributions OWL-AA extends OWL to provide for automated semantic annotation that Embeds instance-recognition semantics declarations in ontologies and data extraction tools Provides enhanced knowledge sharing and reuse via semantic web Separates domain knowledge creation from semantic annotation process Thus maintaining separation between concerns of domain experts and software developers

8 of 20 6 November 2007 ONISW 2007, Auckland, New Zealand Instance Recognition Semantics Instance Semantics Recognizers (ISR’s) Formal specifications that identify instances of a concept in unstructured, semistructured, or structured text Example: Concept: PhoneNumber Text: “Call me at ” ISR should recognize that in the text has the intensional meaning of PhoneNumber.

9 of 20 6 November 2007 ONISW 2007, Auckland, New Zealand ISR Declarations in Data Frames BedroomNr internal representation: Integer external representation: [1-9]|10 left context phrase: \b right context phrase:.*r(oo)?ms? exception phrase: \s.*ba(th)?s?\b.*r(oo)?ms? context keywords: b(r|d)s?|bdrms?|bed(rooms?)?... LessThan(p1: Price, p2: Price) returns (Boolean) context keywords: less than|<|or less|fewer| end Feature external representation: ApartmentFeature.lexicon... end

10 of 20 6 November 2007 ONISW 2007, Auckland, New Zealand Resiliency There are no document layout dependencies in our ISR declarations Other approaches typically use page layout information for extraction Layout independence (resiliency) is a major benefit Page layouts change periodically on the web Different publishers in the same domain generally use different page layouts Rewriting wrappers is costly

11 of 20 6 November 2007 ONISW 2007, Auckland, New Zealand Annotation (Apartment Rental) Feature External Representation BedroomNr External Representation Context Phrase BathNr External Representation Context Phrase MonthRate External Representation Context Phrase ContactPhone External Representation Context Keyword CAPITOL HILL Luxury 2 bdrm 2 bath, 2 grg, w/d, views, 1700 sq ft. $1250 mo. Call

12 of 20 6 November 2007 ONISW 2007, Auckland, New Zealand ISR-Based Annotation Demo demos section

13 of 20 6 November 2007 ONISW 2007, Auckland, New Zealand extractionPattern P RDFS Graph of OWL-AA ISR ExternalRepresentation ContextualRepresentation subClassOf domain &xsd;string range RegularExpression ContextPhrase LexiconList subClassOf ContextKeyword subClassOf LeftContextPhrase RightContextPhrase subClassOf Exception ISRvalue P subClassOf domain range domain owl:Class range domain hasException P extractionRightContext P extractionKeyword P extractionLeftContext P

14 of 20 6 November 2007 ONISW 2007, Auckland, New Zealand OWL-AA Details (1) Add namespace xmlns:owlaa=“ Add properties to OWL classes associating ISR declarations

15 of 20 6 November 2007 ONISW 2007, Auckland, New Zealand OWL-AA Details (2) Declare ISR value and contextual restriction [1-9]|10 <owlaa:extractionLeftContext rdf:resource=“#leftContext-1”/> <owlaa:extractionRightContext rdf:resource=“#rightContext-1”/> <owlaa:extractionKeyword rdf:resource=“#contextKeyword-1”/>

16 of 20 6 November 2007 ONISW 2007, Auckland, New Zealand OWL-AA Details (3) Add context phrases, context keywords, and exceptions \b... (see our paper for the rest of the details)

17 of 20 6 November 2007 ONISW 2007, Auckland, New Zealand OWL-AA Features Syntactically, OWL-AA is attachment- independent w.r.t. OWL No need to change a single line of existing OWL ontologies Semantically, OWL-AA is also attachment- independent w.r.t. OWL ISR declarations do not change meaning of existing ontology concepts at conceptual level Prototype implementation translates OWL-AA to our own internal format for processing

18 of 20 6 November 2007 ONISW 2007, Auckland, New Zealand Related Work We aren’t the first to work on ISR declarations IBM’s Unstructured Information Management Architecture There are many proposals for extending OWL Two extensions related to ours Context OWL (C-OWL) Extension for ontology mapping that localizes ontology content for global visibility OWL-Eu Extension that enriches OWL with customized datatypes, a significant need Not attachment-independent, unfortunately But our approach is compatible with OWL-Eu too

19 of 20 6 November 2007 ONISW 2007, Auckland, New Zealand Conclusion Automated semantic annotation is an important and fundamental problem for the semantic web Key to automated annotation is ISR declaration Our epistemological OWL-AA extension augments OWL to formalize ISR declarations

20 of 20 6 November 2007 ONISW 2007, Auckland, New Zealand Conclusion (cont.) OWL-AA is fully compatible with ordinary OWL Attachable/detachable OWL-AA does not introduce complexity or decidability issues into OWL Prototype implementation demonstrates that our approach works well Embedding epistemological declarations in OWL is a fruitful area meriting further research