Everything you wanted to know about Dublin Core metadata

Everything you wanted to know about Dublin Core metadata but… Tutorial for Eduserv Staff, Bath

Dublin Core, the DCMI Abstract Model & DC Application Profiles Title slide photo “ Orange flavour” by Flickr user kinderu See http://www.flickr.com/photos/kinderu/2328911735/ Made available under CC Attribution- NonCommercial -Share-Alike 2.0 license

Show of Hands Designing/developing metadata applications? Designing/developing Dublin Core metadata applications? Heard of the DCMI Abstract Model? Read the DCMI Abstract Model? Familiar with RDF? Designing/developing RDF applications?

Everything you wanted to know about Dublin Core metadata but... “ Dublin Core” in c.2003 The DCMI Abstract Model DCAM & RDF Syntax: “Encoding” Dublin Core metadata Context & Constraints: “DC Application Profiles” & the Singapore Framework Example: The Scholarly Works (ePrints) DC Application Profile (SWAP) “ Dublin Core” in 2008

“ Dublin Core” in c.2003 Metadata vocabularies … but what is a DC “element”? Syntax independence & encoding guidelines … but what are we “encoding”? “ Simple” and “Qualified” DC … vocabularies? … formats? (e.g. oai_dc) … constraints on use of vocabularies? On which vocabularies? DC application profiles … “ (re)using” terms? But what “terms” can we “(re)use”? Grammatical Principles DC & the Resource Description Framework Absence of domain model(s) the “checklist” approach to DC implementation

The DCMI Abstract Model Work on DCAM by DCMI Architecture Community from mid-2003, initiated by Andy Powell Initial Version, DCMI Recommendation, 2005-03-07 Second Version, DCMI Recommendation, 2007-06-04 http://dublincore.org/documents/2007/06/04/abstract-model/

DCAM and Resources DCAM concerned with description of resources DCAM adopts Web Architecture/RFC3986 definition of resource the term "resource" is used in a general sense for whatever might be identified by a URI. Familiar examples include an electronic document, an image, a source of information with consistent purpose (e.g., "today's weather report for Los Angeles"), a service (e.g., an HTTP to SMS gateway), a collection of other resources, and so on. A resource is not necessarily accessible via the Internet; e.g., human beings, corporations, and bound books in a library can also be resources. Likewise, abstract concepts can be resources, such as the operators and operands of a mathematical equation, the types of a relationship (e.g., "parent" or "employee"), or numeric values (e.g., zero, one, and infinity). RFC3986 URI Syntax

The DCMI Abstract Model DCAM describes Components and constructs that make up an information structure (“DC description set”) How that information structure is to be interpreted Made up of three related “information models” Resource model Description set model Vocabulary model

The DCMI Abstract Model DCAM describes an information structure called a “description set”… … but does not describe how to represent DC description set in concrete form DCMI-defined “Encoding guidelines” Formats defined by others, e.g. Eprints DC-XML DCAM describes various types of metadata term… … but does not specify the use of any fixed set of terms DCMI-owned metadata vocabularies Vocabularies owned/defined by other agencies

DCAM Resource Model The “view of the world” on which DC metadata is based a described resource is described using one or more property-value pairs a property-value pair is made up of exactly one property and exactly one value a value is a resource a value is either a literal value or a non-literal value i.e. similar to RDF model of binary relations between resources; simplified entity-relational model

DCAM Description Set Model The structure of “DC metadata” Uses URIs to refer to resources described & to metadata terms (like RDF) a description set is made up of one or more descriptions , each of which describes one resource a description is made up of zero or one described resource URI identifies described resource one or more statements a statement is made up of exactly one property URI identifies property exactly one value surrogate a value surrogate is either a literal value surrogate or a non-literal value surrogate

Resource URI Resource URI Description Set Description Statement Property URI Literal Value Surrogate Description Statement Property URI Non-Literal Value Surrogate Statement Property URI Non-Literal Value Surrogate

DCAM Description Set Model a literal value surrogate is made up of exactly one value string encodes value a non-literal value surrogate is made up of zero or one value URIs identifies value zero or one vocabulary encoding scheme URI identifies a set of which the value is a member zero or more value strings represents value a value string is either a plain value string or a typed value string a plain value string may have an associated value string language a typed value string is associated with a syntax encoding scheme URI

Value URI Description Set Description Statement Property URI Resource URI Literal Value Surrogate Description Statement Property URI Resource URI Non-Literal Value Surrogate Statement Property URI Non-Literal Value Surrogate Vocab Enc Scheme URI Value URI Value string Value string Syntax Enc Scheme URI Language Value string Language

DCAM Description Set Model a value may be described by another description

Description Set Description Statement Property URI Resource URI Literal Value Surrogate Description Statement Property URI Resource URI Non-Literal Value Surrogate Statement Property URI Non-Literal Value Surrogate Value URI Vocab Enc Scheme URI Value URI Value string Value string Value string Syntax Enc Scheme URI Language Language

Description Set Description Statement Property URI Literal Value Surrogate Description Statement Property URI Resource URI Non-Literal Value Surrogate Statement Property URI Non-Literal Value Surrogate Vocab Enc Scheme URI Value URI Value string Value string Value string Syntax Enc Scheme URI Language Language

Description sets & RDBMS Not a perfect analogy, but… URIs as keys to tables Each description = (roughly) a row in a table Each statement = (roughly) a field name and field content Each literal value surrogate = field content (possibly typed) Each non-literal value surrogate = secondary key (value URI) and/or data from secondary table Description set = some set of rows which it is useful to bundle together

Description Set Description Property URI Resource URI Example: Description set with two descriptions, statements with non-literal value surrogates & literal value surrogates Statement Property URI Non-Literal Value Surrogate Non-Literal Value Surrogate Vocab Enc Scheme URI Value URI Value string Value string Value URI Language Language Description Resource URI Property URI Literal Value Surrogate Value string Language Statement Statement

Description Set Description Statement <http:/purl.org/dc/terms/subject> Non-Literal Value Surrogate Non-Literal Value Surrogate <http://example.org/terms/mySH> “ Metadata” "Métadonnées" en fr <http://purl.org/dc/terms/publisher> <http://dublincore.org/documents/abstract-model/> <http://example.org/org/DCMI> Property URI Value URI <http://example.org/org/mySH/h123> Value URI Property URI Vocab Enc Scheme URI Value String Value String Description <http://example.org/org/DCMI> <http://xmlns.com/foaf/ 0.1/name> Literal Value Surrogate “ Dublin Core Metadata Initiative” en Value String Property URI Example: Description set with two descriptions, statements with non-literal value surrogates & literal value surrogates Statement Statement

@prefix dcterms <http://purl.org/dc/terms/> . @prefix foaf <http://xmlns.com/foaf/0.1/> . DescriptionSet ( Description ( ResourceURI ( <http://dublincore.org/documents/abstract-model/> ) Statement ( PropertyURI ( dcterms:publisher ) ValueURI (<http://example.org/org/DCMI> ) ) Statement ( PropertyURI ( dcterms:subject ) ValueURI (<http://example.org/mySH/h123> ) VocabEncSchemeURI (<http://example.org/terms/mySH> ) ValueString ( “Metadata” Language (en ) ) ValueString ( "Métadonnées" Language (fr ) ) ) ) Description ( ResourceURI ( <http://example.org/org/DCMI> ) Statement ( PropertyURI ( foaf:name ) LiteralValueString ( “Dublin Core Metadata Initiative” Language (en) ) ) ) )

DCAM & RDF A history of co-evolution DCAM grounded in concepts of RDF i.e. assertions of binary relationships between resources (rather informally!) shares RDF Semantics basis for merging, inferencing DCAM Vocabulary Model is RDF Schema Doesn’t explicitly use “description model” of RDF (triple, graph) Mapping from DCAM description model to RDF graph provided by “Expressing DC metadata using RDF”, DCMI Recommendation, 2008-01-14 (Tentative) plans to revise DCAM to base more formally on RDF model

Further references Powell, Nilsson, Naeve, Johnston, Baker. DCMI Abstract Model http://dublincore.org/documents/2007/06/04/abstract-model/ Klyne, Carroll. RDF Concepts and Abstract Syntax http://www.w3.org/TR/rdf-concepts/ Nilsson, Johnston, Naeve, Powell. “Towards an Interoperability Framework for Metadata Standards”. DC-2006 http://www.dublincore.go.kr/dcpapers/pdf/2006/Paper39.pdf Nilsson (ed), Harmonization of Metadata Standards. ProLEARN Project http://ariadne.cs.kuleuven.be/lomi/images/5/52/D4.7-prolearn.pdf

Syntax: “Encoding” Dublin Core metadata

“ Encoding” Dublin Core metadata DCAM description model is syntax-independent For transfer between applications, descriptions must be encoded as digital objects (records) “ Encoding Guidelines” describe how abstract information structure is serialised/encoded using a metadata format how instances of a metadata format are decoded/interpreted in terms of abstract information structure Provider and consumer need shared rules for encoding/decoding DCAM description set as “interface”; concrete syntax as implementation

System A DC Description Set DC-XML Instance Encode using Binding Construct using DCAM & DSP Decode using Binding DC Description Set Interpret using DCAM System B DC-XML Instance <?xml version="1.0"?> <dcx:descriptionSet>

“ Encoding” Dublin Core metadata Multiple syntaxes available Defined by DCMI Defined by other parties Different syntaxes may be appropriate for different contexts “Encoding guidelines” specify what subset of DCAM description model supported how each supported feature of DCAM encoded as syntactic constructs how syntactic constructs interpreted as DCAM features

“ Encoding” Dublin Core metadata Warning! Some of current DCMI “Encoding Guidelines” specs Pre-date development of DCAM Use earlier, simpler “DC abstract models” Not fully compatible with DCAM description set model Updating of specs in progress (2008) Meanwhile, some formats defined outside of DCMI e.g. Eprints DC-XML

DC-RDF “ Expressing DC metadata using RDF”, DCMI Recommendation, 2008-01-14 http://dublincore.org/documents/2008/01/14/dc-rdf/ Uses RDF abstract syntax Supports full DCAM description model Multiple concrete syntaxes available for RDF RDF/XML, N3, Turtle, RDFa etc Stable, complete Example RDF/XML instance

DC-XML-Full “ Expressing DC metadata using XML (DC-XML-Full)”, Working Draft, 2007-06-19 http://dublincore.org/architecturewiki/DCXMLRevision/DCXMLFGuidelines/2007-06-19 Supports full DCAM description model Verbose, but easily processable GRDDL Namespace Transformation to generate RDF/XML To be moved forward (as Proposed Recommendation?), err, some time soon…. Example instance documents http://dublincore.org/architecturewiki/DCXMLRevision/DCXMLFInstances/2007-06-19

DC-XML-Min “ Expressing DC metadata using XML (DC-XML-Min)”, Working Draft, 2007-06-19 http://dublincore.org/architecturewiki/DCXMLRevision/DCXMLMGuidelines/2007-06-19 Supports subset of DCAM description model More compact, but more options to handle Use of QNames for URIs makes it slightly difficult to use with W3C XML Schema GRDDL Namespace Transformation to generate RDF/XML To be revised, need clearer requirements Example instance document http://dublincore.org/architecturewiki/DCXMLRevision/DCXMLMInstances/2007-06-19

DC-HTML “ Expressing DC metadata using HTML/XHTML meta and link elements”, Proposed Recommendation, 2007-11-05 http://dublincore.org/documents/2007/11/05/dc-html/ Supports subset of DCAM description model DC metadata in HTML document describes that document or at least document of which HTML page is representation An HTML meta-data profile GRDDL Profile Transformation to generate RDF/XML Minor amendments required To be moved forward as Proposed Recommendation soon…. Example instance document http://dublincore.org/documents/2007/11/05/dc-html/ex34/ Triples

DC-Text “ Expressing DC metadata using DC-Text”, DCMI Recommended Resource, 2007-12-03 http://dublincore.org/documents/2007/12/03/dc-text/ Supports full DCAM description model Intended for human-readability rather than machine-processing Used in documentation etc Stable, complete (Example instance earlier in presentation)

Further references Nilsson. Basic Syntaxes. Tutorial at DC-2007 http://dc2007.sg/T2-BasicSyntaxes.pdf DCMI Architecture Community Jiscmail list http://www.jiscmail.ac.uk/lists/DC-ARCHITECTURE.html

Context & Constraints: The DCAM & “DC application profiles”

“ DC application profiles” Notion of “DC application profile” widely used within DCMI and by DC implementers Customisation to meet needs of community/domain Typically annotated lists of selected terms to be used in DC metadata Terms defined by DCMI or by other agencies But… Absence of “domain model” Tendency to model of world of homogeneous objects Focus exclusively on vocabulary A “checklist” approach to DCAPs Over-emphasis on 15 properties of DCMES/”Simple DC” Tendency to try to bend/extend 15 properties beyond their intended use…. … or reject DC as not useful

The DCAM & DC Application Profiles Specification of how to construct description sets (descriptions, statements) to serve some purpose At core, a profile of a “description set” a set of constraints based on E-R model of problem space A DC Application Profile is “packet of documentation” which consists of: Functional requirements (desirable) Domain model (mandatory) Description Set Profile (DSP) (mandatory) Usage guidelines (optional) Encoding syntax guidelines (optional)

DCMI Description Set Profile (DSP) A way of describing structural constraints on a description set the resources that may be described by descriptions in the description set the properties that may be referenced in statements the ways a value surrogate may be given Description templates, statement templates Model & XML Syntax for DSP Working draft by Mikael Nilsson ( Royal Institute of Technology, Sweden) http://dublincore.org/documents/2008/03/31/dc-dsp/

Foundation standards Domain standards Application Profile The “Singapore Framework”

Further references Nilsson, Baker, Johnston. The Singapore Framework for Dublin Core Application Profiles http://dublincore.org/documents/2008/01/14/singapore-framework/ Nilsson. Description Set Profiles: A constraint language for Dublin Core Application Profiles http://dublincore.org/documents/2008/03/31/dc-dsp/

Example: The Scholarly Works (ePrints) DC Application Profile (SWAP)

Background to the Eprints DCAP Eprints AP development funded by JISC, Summer 2006 Co-ordinated by Julie Allinson (UKOLN) & Andy Powell (Eduserv Foundation) "eprint": a ''scientific or scholarly research text'‘ (Budapest Open Access Initiative)‏ e.g. peer-reviewed journal article, preprint, working paper, thesis, book chapter, report, etc. Specification for using DC metadata for eprints that overcomes limitations of "Simple DC“ especially relationships between “versions” “ what is being described?”

Components Functional requirements specification Domain model Based on subset of FRBR The "eprints DCAP" a "Description Set Profile" plus human-readable commentary, usage guidelines New vocabularies of metadata terms With URIs like http://purl.org/eprint/terms/xyz Eprints DC-XML XML format Based on DC-XML-Full, Version 2006-09-18

Report of IFLA Study Group, 1998 Entity-Relational model for the “world” that bibliographic records describe FRBR models the world using 4 key entities (Group 1 Entities): a work is a distinct intellectual or artistic creation. A work is an abstract entity an expression is the intellectual or artistic realization of a work a manifestation is the physical embodiment of an expression of a work an item is a single exemplar of a manifestation. The entity defined as item is a concrete entity Primary relationships Work -- is realized through --> Expression Expression -- is embodied in --> Manifestation Manifestation -- is exemplified by --> Item Functional Requirements for Bibliographic Records (FRBR)

FRBR Group 1 Entities Work Expression 1..∞ isRealisedThrough Manifestation isEmbodiedIn ∞ ..∞ Copy isExemplifiedBy 1..∞

Work-Work Relationships Successor, Supplement, Adaptation etc Whole-Part Expression-Expression Relationships Abridgement, Revision, Translation etc Whole-Part Manifestation-Manifestation Relationships Reproduction, Alternate Whole-Part Item-Item Relationships Reconfiguration, Reproduction Whole-Part Functional Requirements for Bibliographic Records (FRBR)

Group 2 Entities: Person, Corporate body Responsibility relationships Work is-Created-By Person/CB Expression is-Realised-By Person/CB Manifestation is-Produced-By Person/CB Item is-Owned-By Person/CB Group 3 Entities: Concept, Object, Event and Place Subject relationships Work has-as-Subject Work/Expression/Manifestation/Item Work has-as-Subject Person/CB Work has-as-Subject Concept/Object/Event/Place Functional Requirements for Bibliographic Records (FRBR)

The eprints DCAP Domain Model ScholarlyWork Expression 0..∞ isExpressedAs Manifestation isManifestedAs 0..∞ Copy isAvailableAs 0..∞ 0..∞ 0..∞ isCreatedBy isPublishedBy 0..∞ isEditedBy 0..∞ isFundedBy isSupervisedBy AffiliatedInstitution Agent

The eprints DCAP Domain Model Expression isExpressedAs Expression isExpressedAs Manifestation Manifestation isManifestedAs isManifestedAs hasAdaptation ScholarlyWork hasVersion hasTranslation Copy isAvailableAs Copy isAvailableAs Copy isAvailableAs

ePrints DCAP attributes/properties (sample) ScholarlyWork: title subject abstract affiliated institution identifier Agent: name type of agent date of birth mailbox homepage identifier Expression: title date available status version number language genre / type copyright holder bibliographic citation identifier Manifestation: format date modified Copy: date available access rights licence identifier

The eprints DCAP as DSP Developed initially using "traditional" "tabular" DCAP presentation Retrospectively used as test case for DSP model Document divided into five sections/tables, one for description of each entity type -> DSP Description Template Each section/table divided into rows, one for each statement type within description -> DSP Statement Template For statement referencing Literal Value -> DSP Literal Value Constraint For statement referencing Non-Literal Value -> DSP Non-Literal Value Constraint http:// www.ukoln.ac.uk/repositories/digirep /index/ EPrints_Application_Profile

Thoughts on the Approach (Julie Allinson) Driven by the functional requirements identified Makes it easier to rationalise ‘traditional’ and ‘modern’ citations traditional citations tend to be made between eprint ‘expressions’ hypertext links tend to be made between eprint ‘copies’ (or ‘items’ in FRBR terms)‏ A complex underlying model may be manifest in relatively simple cataloguer and/or end-user interfaces Existing eprint systems may well capture this level of detail currently – but emphasis on simple DC stops them exposing it to others!

Further references Allinson, Powell. Eprints Application Profile http://www.ukoln.ac.uk/repositories/digirep/index/Eprints_Application_Profile Allinson, Johnston, Powell. “A Dublin Core Application Profile for Scholarly Works” Ariadne 50 (Jan 2007) http://www.ariadne.ac.uk/issue50/allinson-et-al/ IFLA. Functional Requirements for Bibliographic Records. 1998, 2007 http://www.ifla.org/VII/s13/frbr/

Dublin Core in 2008 a framework (the DCAM) which describes how to use certain types of terms ... to make statements ... ... that form descriptions (of resources) … that can be grouped together as description sets a set of specifications for encoding description sets using various formats a managed vocabulary of widely useful terms which can be referenced in statements a vocabulary model & support for defining additional vocabularies of terms which can be referenced in statements a profile model & support for defining DC application profiles which describe how to construct description sets for some particular set of requirements extensibility, modularity, structural validation, compatibility with Semantic Web

Dublin Core in 2008 Current DCMI work in progress Generally, shift from focus on vocabularies to framework and its use in DCAPs Updating “encoding guidelines” for DC-XML, DC-HTML Finalising Description Set Profile model & syntax Developing guidelines for creating DCAPs (including DSPs) Working with IEEE LOM community on expressing LOM metadata using DCAM Working with library community on revision of core library metadata standards in RDA initiative (using FRBR & DCAM) Future? Sort out messy documentation! Clarify formal relationship between DCAM and RDF? New “encoding guidelines” for e.g. RDFa? DC metadata as Linked Data? Relationship to “informal metadata” (tagging etc)?

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