Presentation on theme: "Application profiles Tutorial session Rachel Heery, UKOLN, University of Bath www.ukoln.ac.uk DC-2003, Seattle, Washington, USA 28 September – 2 October,"— Presentation transcript:
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 Profile Case study 2: DC Government Application Profile Summing Up
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
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 published but Implementor adaptations and extensions are not made widely available Sharing semantics will reduce duplication and repetition
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 14855 26 September 2003 Dublin Core Application Profile Guidelines Final Draft Thomas Baker, Makx Dekkers, Thomas Fischer, Rachel Heery www.cenorm.be/sh/mmi-dc ftp://ftp.cenorm.be/PUBLIC/ws-mmi-dc/
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 profile http://www.rdn.ac.uk/oai/rdn_dc/ Renardus Application Profile http://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 TitleRDN OAI Application Profile ContributorAndy Powell Date2003-03-23 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/http://www.rdn.ac.uk/oai/rdn_dc/
NameSubject Term URIhttp://purl.org/dc/elements/1.1/subject Has Encoding Scheme DC Subject Encoding Schemes Has Encoding Scheme RDN Subject Encoding Schemes CommentRDN Subject Encoding Schemes are available from http://www.rdn.ac.uk/publications/cat- guide/subject-schemes/ http://www.rdn.ac.uk/publications/cat- guide/subject-schemes/ ObligationRecommended 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/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/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/ 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
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.