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• http://nkos.slis.kent.edu/

– SEMKOS FP6 IP Proposal • http://www.lub.lu.se/SEMKOS/

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, http://www.clir.org/pubs/abstract/pub91abst.html

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 schemasJaco03, 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

http://nkos.slis.kent.edu/VOCML-1.DOC

http://www.lub.lu.se/netlab/conf/busch.ppt

• RDF Thesaurus Interchange FormatLimber Project - ELSST multilingual thesaurushttp://www.ercim.org/publication/Ercim_News/enw51/wilson.html

• DESIRE II - RDF Thesaurus Specificationhttp://ilrt.org/discovery/2001/01/rdf-thes/

NKOS Registry - draft proposal for KOS-level metadata http://staff.oclc.org/~vizine/NKOS/Thesaurus_Registry_version3_rev.htm

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, RelationshipsRelationships 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 correlationhttp://jodi.ecs.soton.ac.uk/Articles/v01/i08/Doerr/

– Related KOS versioning and update tools

eg obsoletion, sibling addition, change of meaning

– CIDOC Conceptual Reference Model Cultural heritage metadata framework (ISO/CD 21127)

http://www.cultivate-int.org/issue9/chios/

• Renardus - common classification/browsing structure and cross-browsing service

http://www.renardus.org

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 Workshophttp://www.lub.lu.se/SEMKOS/docs/Hill_KOSpaper7-2-final.doc

• 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

• http://www.alexandria.ucsb.edu/thesaurus/protocol

see also

• Zthes Z39.50 protocol - http://zthes.z3950.org/index.html

Possible KOS-based Terminology Server within JISC Information Environment

Broker / Aggregator

Port al Port al

Content providers

End-user

Port al

Broker / Aggregator

Authenticat ion

Author isation

Resolver

I nst’n Profi le

Shared servicesProvisionlayer

Fusionlayer

Presentationlayer

Serviceregistry

Terminologyservice

1

2

3

4 5

Enriching / Formalising KOS

• Not only a matter of representation in RDF/XML

- may be inconsistencies in logical structureeg 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 ontologiessimilar 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)http://www.glam.ac.uk/soc/research/hypermedia/facet_proj/

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

http://www.lub.lu.se/desire/DESIRE36a-overview.html

Need to consider whole lifecycle ctd.

• Cost/benefit issues when enriching KOS?Different levels

specialisation of standard relationships first step?

Application dependent

• User interface criticalmove beyond minimal assumptions

of current web search engines on

users, query structure, collections

NKOS Workshops at ECDL and JCDLon related themes to this NeSC workshop

• NKOS Workshop - Evolving StandardsECDL2003, Trondheim, 21 August 2003

cfp soon - email dstudhope@glam.ac.uk

or see http://www.ecdl2003.org & http://nkos.slis.kent.edu

• NKOS Workshop - Building a Meaningful WebJCDL03, Houston, Texas, May 31

see http://nkos.slis.kent.edu

• 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):381-400.

Bechofer S., Goble C. 2001. Thesaurus construction through knowledge representation. Data & Knowledge Engineering, 37, 25-45.

CIDOC Conceptual Reference Model, http://www.cultivate-int.org/issue9/chios/

Cross P., Brickley D., Koch. T. 2000. Conceptual relationships for encoding thesauri … http://www.desire.org/results/discovery/rdfthesschema.html

Doerr M. 2001. Semantic Problems of Thesaurus Mapping. Journal of Digital Information, 1(8) -http://jodi.ecs.soton.ac.uk/Articles/v01/i08/Doerr/

FACET Project. http://www.glam.ac.uk/soc/research/hypermedia/facet_proj/

Global Taxonomy Initiative. http://www.biodiv.org/programmes/cross-cutting/taxonomy/gef-gti.asp

Hill et al. 2002. Integration of Knowledge Organization Systems into Digital Library Architectures. ASIST SigCR - http://www.lub.lu.se/SEMKOS/docs/Hill_KOSpaper7-2-final.doc

Hodge Gail, 2000. Systems of Knowledge Organization for Digital Libraries: Beyond Traditional Authority Files. CLIR Pub91. April 2000. http://www.clir.org/pubs/abstract/pub91abst.html

Jacob Elin. 2003. Ontologies and the Semantic Web. ASIST Bulletin, April/May 2003, Special Issue on Semantic Web. http://www.asis.org/Bulletin/Apr-03/BulletinAprMay03.pdf

Janée G., Ikeda S., Hill L. 2002. ADL Thesaurus Protocol v1.0. http://www.alexandria.ucsb.edu/thesaurus/protocol and http://nkos.slis.kent.edu/2002workshop/janee.ppt

Koch T., Ardoe A. 2000. DESIRE II Overview of Results and Demo. http://www.lub.lu.se/desire/DESIRE36a-overview.html

References ctd.

Renardus Project - http://www.renardus.org

NKOS: Networked Knowledge Organization Systems/Services, http://nkos.slis.kent.edu/

NKOS Registry - draft proposal for KOS-level metadata http://staff.oclc.org/~vizine/NKOS/Thesaurus_Registry_version3_rev.htm

SEMKOS FP6 IP Proposal, http://www.lub.lu.se/SEMKOS/

Soergel D. 1994 Indexing and retrieval performance: The logical evidence. Journal of American Society for Information Science, 45(8): 589-599.

Taylor M. 2000. Zthes: a Z39.50 Profile for Thesaurus Navigation Version 0.4. http://lcweb.loc.gov/z3950/agency/profiles/zthes-04.html

Tudhope D., Alani H., Jones C. 2001. Augmenting thesaurus relationships: possibilities for retrieval. Journal of Digital Information, 1(8) - http://jodi.ecs.soton.ac.uk/Articles/v01/i08/Tudhope/

Tudhope D., Binding C., Blocks D., Cunliffe D. 2002. Compound Descriptors in Context: A Matching Function for Classifications and Thesauri. Proc. 2nd Joint Conference on Digital Libraries. ACM Press. 84-93 http://www.glam.ac.uk/soc/research/hypermedia/publications/jcdl02.pdf

VocML. 2000. Vocabulary ML Project. http://nkos.slis.kent.edu/VOCML-1.DOC and http://www.lub.lu.se/netlab/conf/busch.ppt

Wilson M., Matthews B. 2002. Migrating Thesauri to the Semantic Web. http://www.ercim.org/publication/Ercim_News/enw51/wilson.html

Contact Information

Doug Tudhope

School of Computing

University of Glamorgan

Pontypridd CF37 1DL

Wales, UK

dstudhope@glam.ac.uk

http://www.comp.glam.ac.uk/pages/staff/dstudhope