Sem Ref An Evaluation Reference Model for Semantic

Sem. Ref: An Evaluation Reference Model for Semantic Metadata IST-FP 6 -26978 Introduction A crucial condition for realizing the Semantic Web vision is the existence of high quality semantic metadata that enrich web resources or denote real world objects. The key contribution of this poster is an evaluation reference model, Sem. Ref, which proposes some foundations for the evaluation of semantic metadata. The term quality refers to the fitness of semantic metadata in: • capturing the meaning of the data sources they describe • instantiating the ontologies they subscribe to. An Overview Described real-world objects: People: Neil Benn, Simon Buckingham Shum, Bertrand Sereno, Murray Altheim, Clara Mancini, David Kolb Organizations: University of Nottingham, ACM Real World Describing Modelling AKT Support Ontology AKT Portal Ontology Describing KMi Ontology Ontologies Data Sources KMi Semantic Web Instantiating Annotating Semantic Metadata <ksw: kmi-planet-news-item rdf: ID="planet-news-story 263"> <akt: has-author rdf: resource="#kmi-reporter" /> … <ksw: mentions-kmi-person rdf: resource="#Clara Mancini"/> <ksw: mentions-kmi-person rdf: resource="#Clara"/> <ksw: mentions-kmi-person rdf: resource="#Neil Benn"/> <ksw: mentions-non-kmi-person rdf: resource="#Neil Benn"/> <ksw: mentions-kmi-person rdf: resource="#Simon Buckingham"/> <ksw: mentions-organization rdf: resource="#international-workshop"/> <ksw: mentions-organization rdf: resource="#workshop-chair"/> <ksw: mentions-organization rdf: resource="#university-of-edinburgh"/> </ksw: kmi-planet-news-item> Reference Elements The Data Sources The Real World The data sources depict various information about the world and need to be properly annotated. Deficiency examples: Data Source The Underlying Ontologies The real world is constituted by abstract concepts, instances of the abstract concepts, and their relations. Deficiency example: Deficiency examples: Semantic Metadata Real World The underlying ontologies model the real world in a domain specific context. Semantic Metadata C 1 R 2 Incomplete Annotation Data Source Semantic Metadata R 2 C 3 Spurious Representation Real World Ontology Semantic Metadata Inconsistent Representation. Imagine the underlying ontology specifies that instances of the class C 1 should only contain one value in relation R 2. When an instance contains two values, the representation is inconsistent with the constraint. Ambiguous Annotation Duplicate Representation Contacts: Yuangui Lei, Victoria Uren, Enrico Motta Knowledge Media Institute, the Open University, Milton Keynes, UK, MK 7 6 AA Tel: +44 (0) 1908 659835 Fax: +44 (0) 1908 653169 Email: {y. lei, v. s. uren, e. motta}@open. ac. uk