Application profiles

Tutorial session

Rachel Heery, UKOLN, University of Bath

www.ukoln.ac.uk

DC-2003, Seattle, Washington, USA

28 September – 2 October, 2003

                                                             

Contents

What problem are we solving? Way forward?

DC Application Profile Guidelines

Case study 1 : DC Library Application ProfileCase study 2: DC Government Application Profile

Summing Up

                                                             

What problem are we solving?

                                                             

Proliferation of metadata

Increase in requirement for metadata

– Corporate portals– Subject gateways– eCommerce– eScience– Rights– Web Services

Appropriate terms must be identified wherever metadata is needed

                                                             

Proliferation of standards

Descriptive metadata – DCMI – IEEE LOM– GILS– METS– MODS– MARC 21– UNIMARC– MPEG-7

                                                             

Implementor perspective

Implementors are seeking a standard for their particular service or system

• Implementors approve of re-use • Implementors acknowledge importance of

interoperability• …. but there is pressure to satisfy local

requirements and to be innovative

Tension between using a standard and localisation

                                                             

Proliferation of localised extensions

• Metadata standards are publishedbut

• Implementor adaptations and extensions are not made widely available

Sharing semantics will reduce duplication and repetition

                                                             

Way forward….

                                                             

Exchange data about new terms

What terms does your metadata use?

Express in structured way• Which standard terms are used in an

application• How terms are adapted or used locally• Other related usage constraints

Caveat: first step is human readable !

                                                             

Aims of application profiles

• To provide authoritative specification of term usage

• To facilitate interoperability by informing unknown targets

• To support evolution of vocabulary

• To encourage alignment

                                                             

Profiling is not new…

• MARC local fields– 9XX and XX9 tags

• Z39.50 application profiles– sub-sets of standard appropriate for application

area

• IEEE LOM– UK Common Metadata Format

• Project specific activity– Defining schema

                                                             

What does an application profile express?

Implementors need to declare various characteristics of their schema

• Terms in use• Whether a term is mandatory• Any refinement of standard definitions of terms • Schemes for values • Other rules for content

                                                             

Examples of application profiles• RSLP Collection Level description• TEL (The European Library)• Australian Government Locator Service• Food and Agricultural Organisation• European Environment Agency• Various UK educational initiatives

– UK CMF, Qualifications and Curriculum Authority, Virtual Teacher Centre,

• DCMI Application Profiles– Libraries, Education

                                                             

RSLP Collection Level Description

• Enabling RSLP projects to describe collections in a consistent and machine readable way

• For simple description of collections, locations and related people

• Uses qualified DC with additional local RSLP terms

http://www.ukoln.ac.uk/metadata/rslp/

                                                             

The European Library (TEL) application profile

• Starting point was DC-Lib AP• TEL-specific additions to support desired

functionality e.g.– OpenURL (get local services for this record) – RecordId (get original record) – Thumbnail (thumbnail image)

• Why? acknowledged need for controlled evolution of metadata terms– the ability to add future functionality may depend on additional terms– new sectors/collections may require specific terms

http://www.europeanlibrary.org/

                                                             

Virtual Teacher Centre

• Virtual Teacher Centre (VTC) Metadata Standard

• To describe educational resources, including the content of the Virtual Teacher Centre website

• Based on DCMI terms, National Curriculum Metadata Standard and local VTC terms

http://vtc.ngfl.gov.uk/

                                                             

Format of DCAPs

• Normalized and readable view of Dublin Core based schemas for use by humans– No particular format mandated: plain text, Web

pages, Powerpoint…

• Enough structure for future conversion into machine-processable expressions (eg, RDF)– Future conversion not assumed to be automatic– Caveat: normalized documentation does not in

itself address deeper problems of interoperability between metadata models.

                                                             

CEN Workshop Agreement 1485526 September 2003

Dublin Core Application Profile Guidelines Final DraftThomas Baker, Makx Dekkers, Thomas Fischer, Rachel Heery

www.cenorm.be/sh/mmi-dcftp://ftp.cenorm.be/PUBLIC/ws-mmi-dc/

                                                             With acknowledgement to Tom Baker….

                                                             

DC Application Profiles

• Declaration specifying which metadata terms an information provider uses in metadata– Identifies source of terms used– May provide additional documentation

• Designed to promote interoperability within constraints of Dublin Core model– Many purposes in practice – harmonization,

"emerging semantics", interpreting legacy metadata…

– May evolve over time through incremental improvement

                                                             

DCAPs “by definition”

• Based (in part) on Dublin Core• Follow DCMI Grammatical Principles

– Simple model of a resource with a flat set of properties

• Consist of Descriptive Header and Term Usages– Descriptive Header

• DC-based description • Optional Preamble

– Term Usage• Terms used identified with "appropriate precision"• May be annotated with additional attributes and constraints

                                                             

Attributes of Term Usages

• Identifying attributes– Term URI, Name, Label, Defined By

• Definitional attributes– Definition, Comments, Type of Term

• Relational attributes– Refines, Refined By, Encoding Scheme For,

Uses Encoding Scheme, Similar To

• Constraints– Obligation, Condition, Datatype, Occurrence

                                                             

Principle of Appropriate Identification

Terms should be identified "as precisely as possible" ("appropriate precision")– In accordance with CORES Resolution,

URIs should be used when available– Terms to which URIs have not (or not yet)

been assigned should be identified using other attributes as appropriate

                                                             

Identifying terms

• Term used in a Term Usage should be identified with appropriate precision

• Preferred: cite term's URI if available– Term URI http://purl.org/dc/terms/audience

• Or if a term has been declared somewhere, cite the defining document and its name– Name attendancePattern– Label Attendance Pattern– Defined By http://someones-project.org/schema.html

• If term has not been declared elsewhere, Defined By should cite the DCAP itself– Name starRatings– Label Star Ratings– Defined By http://myproject.org/profile.html

                                                             

Principle of Readability

• "DCAP should include enough information in Term Usages to be of optimal usefulness for the intended audience"– Even if this redundantly includes information

which, in a machine-processable schema, might be fetched dynamically from another source

– Order of attributes may be changed for readability (though it may make visual comparison harder)

– Unused attributes can simply be omitted from display

                                                             

Readability of Term Usages

Principle of Readability allows flexibility in presentational style

• Redundant attributes do not need to be displayed (as blank)

• Order of attributes may be altered for visual effect (not significant for future machine-processable representations)

• DCAP may want to group terms by Type of Term

• Attributes should be repeated as necessary

                                                             

Controlled vocabulary terms

• Generally not the role of DCAPs to declare controlled vocabularies of values

• Ideally, should be declared in separately citable documents external to a DCAP

• However, short lists of possible values may be documented in a Comment field

                                                             

Using Encoding Schemes

Options– Can be declared one-by-one in the Term Usage

of an Element in the field "Has Encoding Scheme"

– Field "Has Encoding Scheme" can point to a list of encoding schemes somewhere (e.g. "use RDN Subject Encoding Schemes…")

– If Encoding Schemes need to be annotated, a separate Term Usage may be created for each

                                                             

Using Element Refinements

Options– Blanket statements in a "Refined By" field ("all

terms in Vocabulary D can be used as element refinements for Contributor")

– Cite Element Refinements one-by-one using the attribute Refined By under the Term Usage of an Element

– Create a separate Term Usage for each Element Refinement

                                                             

Term URIs

• URIs are (ideally) unique and unambiguous:– Example: http://purl.org/dc/elements/1.1/title

• Qualified Names use a prefix standing for a namespace

• For readability (and by popular demand), Qualified Names can be cited in Name field– Example: dc:title – Explain in the Preamble that this is the case– Also cite the URIs

                                                             

Examples

• RDN OAI application profilehttp://www.rdn.ac.uk/oai/rdn_dc/

• Renardus Application Profilehttp://renardus.sub.uni-goettingen.de/renap/renap.html

• UK e-Government Metadata Standard Application Profile

http://purl.oclc.org/NET/e-GMS-AP_v1

                                                             

RDN OAI Application Profile - header

Title RDN OAI Application Profile

Contributor Andy Powell

Date 2003-03-23

Identifier

Description This document expresses the application profile established by the Resource Discovery Network (RDN) to be used by RDN partners for harvesting of records using the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH). The Application Profile is expressed according to guidelines published by the CEN/ISSS [Reference]. Full user documentation for the Application Profile, together with associated XML schemas, is available at http://www.rdn.ac.uk/oai/rdn_dc/

                                                             

Name Subject

Term URI http://purl.org/dc/elements/1.1/subject

Has Encoding Scheme

DC Subject Encoding Schemes

Has Encoding Scheme

RDN Subject Encoding Schemes

Comment RDN Subject Encoding Schemes are available from http://www.rdn.ac.uk/publications/cat-guide/subject-schemes/

Obligation Recommended

RDN OAI Application Profile – term usage

                                                             

Further reading

Rachel Heery & Manjula Patel, Application Profiles: mixing and matching metadata schemas. Ariadne, September 2000. http://www.ariadne.ac.uk/issue25/app-profiles/http://jodi.ecs.soton.ac.uk/Articles/v02/i02/Baker/

Thomas Baker, Makx Dekkers, Rachel Heery, Manjula Patel, Gauri Salokhe, What Terms Does Your Metadata Use? Application Profiles as Machine-Understandable Narratives. Journal of Digital Information, Vol.2, no. 2, November 2001. http://jodi.ecs.soton.ac.uk/Articles/v02/i02/Baker/

Heike Neuroth and Traugott Koch, Metadata mapping and application profiles: approaches to providing the cross-searching of heterogeneous resources in the EU project Renardus. DC-2001: proceedings of the International Conference on Dublin Core and Metadata Applications, Tokyo. http://www.nii.ac.jp/dc2001/proceedings/

Thomas Baker and Makx Dekkers, Identifying metadata elements with URIs: the CORES Resolution. D-Lib magazine, July/August 2003.http://www.dlib.org/dlib/july03/baker/07baker.html

                                                             

Questions?

                                                             Case studies….

                                                             

Terminology

• Data Element: A formally defined term used to describe an attribute of a resource. A unit of data for which the definition, identification, representation, and permissible values can be specified.

• Element Set: A coherent bounded set of

Elements formulated as a basis for metadata creation. An Element Set is managed as an entity.

                                                             

More terminology• Element Usage: A deployment of a (previously defined)

metadata Element in the context of a particular domain or application.

• Application Profile: A set of Element Usages optimised

for the resource description requirements of a particular application or context. An Application Profile is managed as an entity.

• Schema: A structured representation of one or more Element Sets, Application Profiles or Encoding Schemes.