1 Dublin Core and its implementation in RDF/XML Paul Miller Interoperability Focus UK Office for Library & Information Networking (UKOLN) UKOLN is funded by the Library and Information Commission, the Joint Information Systems Committee (JISC) of the Higher Education Funding Councils, as well as by project funding from the JISC and the European Union. UKOLN also receives support from the Universities of Bath and Hull where staff are based.

2 Introducing the Dublin Core An attempt to improve resource discovery on the Web –now adopted more broadly Building an interdisciplinary consensus about a core element set for resource discovery –simple and intuitive –cross–disciplinary — not just libraries!! –international –open and consensual –flexible. See

3 15 elements of descriptive metadata All elements optional All elements repeatable The whole is extensible –offers a starting point for semantically richer descriptions Interdisciplinary –libraries, government, museums, archives… International –available in more than 20 languages, with more on the way... Introducing the Dublin Core

4 Title Creator Subject Description Publisher Contributor Date Type Format Identifier Source Language Relation Coverage Rights Introducing the Dublin Core

5 Introducing XML eXtensible Markup Language World Wide Web Consortium recommendation Simplified subset of SGML for use on Web Addresses HTML’s lack of evolvability Easily extended Supported by major vendors Increasingly used as a transfer syntax, but capable of far more…. See

6 Introducing RDF Resource Description Framework W3C Recommendation Improves upon XML, HTML, PICS… Machine understandable metadata! XML as syntax Locally defined semantics Supports structure Increasing interest. See dc/datamodel/WD–dc–rdf/ See dc/datamodel/WD–dc–rdf/ See

7 Extending DC (semantic) Improve descriptive precision by adding sub–structure (subelements and schemes) –Greater precision = lesser interoperability Should ‘dumb down’ gracefully Creator First Name Surname Contact Info Affiliation Based on a slide by Stu Weibel Element qualifierValue qualifier

8 Extending DC (modularity) Modular extensibility… Additional elements to support local needs Complementary packages of metadata …but only if we get the building blocks right! DescriptionSpatial character Terms & Conditions Based on a slide by Stu Weibel

9 Data Integration “The author of this document is Paul” “Paul is the author of this document” “This document is authored by Paul” “The author of this document is Paul” At least 3 Representation(s) in XML: Paul Paul <document href = “ author = “Paul” />

10 Data Integration Querying XML documents is hard N ways of mapping XML to logical structure Requires the normalization of all possible representations for effective query Mean the same thing to a person Mean very different things to a machine RDF much less flexible less flexible = more interoperable! consistent way of representing statements.

11 RDF Data Model basics Resource Property Value Resource Statement

12 A simple example Resource Author “Paul”

13 DC in RDF Draft proposal of Dublin Core community’s Data Model working group Guidance on expressing the Dublin Core within the Resource Description Framework (RDF) dc/datamodel/WD-dc-rdf/

14 Dublin Core ‘Data Model’ rdf:Valuedc : element Resource dcq:elementType (element qualifier) dcq:elementScheme (value qualifier) Based on a slide by Stu Weibel

15 A simple example “Created” dcq:dateType “ ” rdf:Valuedc:date Resource “ISO 8601” dcq : dateScheme Based on a slide by Stu Weibel

16 A simple example Guidance on expressing the Dublin Core within the Resource Description Framework (RDF) Eric Miller Paul Miller Dan Brickley Dublin Core; Resource Description Framework; RDF; eXtensible Markup Language; XML Dublin Core Metadata Initiative Dublin Core Data Model Working Group text/html en

17 A scary example… part 1 Guidance on expressing the Dublin Core within the Resource Description Framework (RDF) Veiledning å uttrykke Dublin Core innenfor rammen av Resource Description Framework (RDF) Dublin Core in RDF: Eine Anleitung

18 A scary example… part 2! Eric Miller Paul Miller Dan Brickley This document describes work carried out by the Data Model Working Group of the Dublin Core Metadata Initiative… Dette dokumentet beskriver arbeide utført av arbeidsgruppen for datamodellering knyttet til Dublin Core- initiativet. Spesifikt diskuterer dokumentet hvordan de femten elementene i Dublin Core …

19 A scary example… part 3!! Dublin Core; Resource Description Framework; RDF; eXtensible Markup Language; XML Dublin Core Metadata Initiative Dublin Core Data Model Working Group WTN IMT text/html

20 A scary example… part 4!!! RFC1766 en

21 Useful Links Dublin Core RDF XML DC–Dot SiRPAC DC Datamodel Document dc/datamodel/WD-dc-rdf/