Knowledge Organisation Systems Doug Tudhope Hypermedia Research Unit University of Glamorgan Schemas and Ontologies Workshop, NeSC, May 2003

Presentation Introduce Knowledge Organisation Systems (KOS) Review some current DL work on KOS Research Issues –draw connections with Ontologies and Semantic Grid General sources –NKOS: Networked Knowledge Organization Systems/Services –SEMKOS FP6 IP Proposal

Taxonomy of Knowledge Organisation Systems Term Lists –Authority Files, Glossaries, Gazetteers, Dictionaries Classification and Categorization –Subject Headings –Classification Schemes and Taxonomies eg DDC, scientific taxonomies Relationship Schemes –Thesauri –Semantic Networks –(Ontologies) Hodg00,

KOS ctd. Thesauri –3 Standard Relationships between concepts Equivalence, Hierarchical, Associative –Domain (lead-in) vocabulary –Concept definitions and warrant (Scope Notes) Ontologies –Higher level conceptualisation formal definition of relationships inference rules and definition of roles KOS an element of ontologies and schemas Jaco03, Ontologies and the Semantic Web,. ASIST Bulletin, April/May 2003, Special Issue on Semantic Web

KOS Legacy Large (multilingual) vocabularies, indexed multimedia (and print) collections, scientific taxonomy initiatives Product of peer review and follow standards Network of practice, training and mechanisms for evolution However Cannot currently be utilised to full potential –Designed for human inspection, semantic structure not explicitly represented –May be inconsistently evolved from various sources Opportunity to formalise / enrich –exploiting semantic web technologies

International Thesaurus Standards Ongoing initiatives to revise thesaurus standards ANSI/NISO Z39.19 (monolingual) IFLA (multilingual) BS 5723 and BS 6723 (both) - BSI public draft soon Extended scope, comparisons, interoperability Various proposals to extend current relationships by specialisation, enriching standards but maintaining compatibility (eg Tudh01)

Representation of KOS in RDF/XML Various RDF/XML KOS-based projects Eg Voc-ML XML Schema RDF Thesaurus Interchange Format Limber Project - ELSST multilingual thesaurus l DESIRE II - RDF Thesaurus Specification

NKOS Registry - draft proposal for KOS-level metadata Follows Dublin Core, data elements include: KOS - Title, Creator, Publisher, Date, Type, Format, Identifier, Language KOS - Subject, Description, Application, Rights Need for for more definition of purpose and usage? - the point of view KOS - Relation (URI etc) KOS - Entity Types, Info Given, Relationships Relationships defined via a standard Namespace? Uniquely identify both the KOS and relationships within the KOS.

Cross - mapping/browsing/searching KOS Cross Mapping and semi-automatic KOS correlation –Related KOS versioning and update tools eg obsoletion, sibling addition, change of meaning –CIDOC Conceptual Reference Model Cultural heritage metadata framework (ISO/CD 21127) Renardus - common classification/browsing structure and cross-browsing service

Research issues KOS services for DL and Semantic Grid Facet analysis and foundational concepts - complementary approaches? Whole lifecycle considerations

KOS integration into DL services Linda Hill Research Agenda for ASIST SigCR Workshop General KOS service protocol from which protocols for specific types of KOS can be derived Robust linking model in which DL entities (collections, objects, and services) can refer to KOS entities (concepts, labels, and relationships) Visualization tools that fully use and display the rich semantics embedded in KOS => move towards a model of search service flow? - how semantic search services combine

Standard protocols for distributed access ADL Thesaurus Protocol (and Gazetteer Protocol) –lightweight, stateless, based on XML, HTTP Services include: download -> list of all terms query -> list of matching terms (equals/contains/fuzzy etc matches) get-broader(starting-term, max-levels, format) -> hierarchy –format: "term", "term-description", or "extended" get-narrower([starting-term,] max-levels, format) -> hierarchy see also Zthes Z39.50 protocol -

Possible KOS-based Terminology Server within JISC Information Environment

Enriching / Formalising KOS Not only a matter of representation in RDF/XML - may be inconsistencies in logical structure eg combination of different hierarchical relationships --> deconstruction and ontological formalisation --> mutually exclusive concept structures suitable for automatic methods Facet analysis techniques relevant Faceted (analytico-synthetic) approaches –based on fundamental, high-level categories –synthetic rather than enumerative combine facets when indexing/querying

Facet Analysis UK Classification Research Group extended Ranganathan's set of fundamental categories Entity, Part, Property, Material, Process, Operation, Product, Agent, Space, Time,... Mapped to facets for particular KOS Basis of several scientific and industrial KOS Useful for cleaning KOS, multi-concept indexing and potential for precision in search However Synthesis rules for facet combination lack formal expression

Foundational concepts and facets Foundational concepts and relations in ontologies similar fundamental categories to CRG (and CRM) but logically expressed and axiomatised can provide Additional formalisms to logically express 'syntactical' combination of facets (eg Bech01) can assist Automatic generalisation (expansion) of faceted multi-concept queries/descriptors

Faceted multi-concept generalisation (Tudh02)

Need to consider whole lifecycle Importance of indexing for retrieval performance Inter-relation of different stages of lifecycle (eg Bate02; Soer94) Make indexing practice more explicit? –KOS Registry include description of indexing praxis? Differences in granularity, exhaustivity, specificity in usage of different kinds of KOS –eg Classification Vs Thesaurus (indexing language) Automatic KOS-based indexing/classification –DESIRE II, Scorpion Projects

Need to consider whole lifecycle ctd. Cost/benefit issues when enriching KOS? Different levels specialisation of standard relationships first step? Application dependent User interface critical move beyond minimal assumptions of current web search engines on users, query structure, collections

NKOS Workshops at ECDL and JCDL on related themes to this NeSC workshop NKOS Workshop - Evolving Standards ECDL2003, Trondheim, 21 August 2003 cfp soon - or see & NKOS Workshop - Building a Meaningful Web JCDL03, Houston, Texas, May 31 see Selected papers from the NKOS workshops will be considered for forthcoming special issues of journals JoDI and NRHM

References Bates, Marcia The Cascade of Interactions in the Digital Library Interface. Information Processing and Management 38 (2002): Bechofer S., Goble C Thesaurus construction through knowledge representation. Data & Knowledge Engineering, 37, CIDOC Conceptual Reference Model, Cross P., Brickley D., Koch. T Conceptual relationships for encoding thesauri … Doerr M Semantic Problems of Thesaurus Mapping. Journal of Digital Information, 1(8) - FACET Project. Global Taxonomy Initiative. Hill et al Integration of Knowledge Organization Systems into Digital Library Architectures. ASIST SigCR - Hodge Gail, Systems of Knowledge Organization for Digital Libraries: Beyond Traditional Authority Files. CLIR Pub91. April Jacob Elin Ontologies and the Semantic Web. ASIST Bulletin, April/May 2003, Special Issue on Semantic Web. Janée G., Ikeda S., Hill L ADL Thesaurus Protocol v and Koch T., Ardoe A DESIRE II Overview of Results and Demo.

References ctd. Renardus Project - NKOS: Networked Knowledge Organization Systems/Services, NKOS Registry - draft proposal for KOS-level metadata SEMKOS FP6 IP Proposal, Soergel D Indexing and retrieval performance: The logical evidence. Journal of American Society for Information Science, 45(8): Taylor M Zthes: a Z39.50 Profile for Thesaurus Navigation Version Tudhope D., Alani H., Jones C Augmenting thesaurus relationships: possibilities for retrieval. Journal of Digital Information, 1(8) - Tudhope D., Binding C., Blocks D., Cunliffe D Compound Descriptors in Context: A Matching Function for Classifications and Thesauri. Proc. 2 nd Joint Conference on Digital Libraries. ACM Press VocML Vocabulary ML Project. and Wilson M., Matthews B Migrating Thesauri to the Semantic Web.

Contact Information Doug Tudhope School of Computing University of Glamorgan Pontypridd CF37 1DL Wales, UK