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v 3.3.8

Overview

The Dublin Core Metadata Initiative's Metadata Registry is an application designed to promote the discovery and reuse of exiting metadata definitions. Discovery and reuse are essential to standardization, and promote greater interoperability between metadata element sets.

The DCMI Metadata Registry provides users and applications with an authoritative source of information about the Dublin Core element set and related vocabularies. This information is intended to simplify the discovery of terms, and their definitions, and to illustrate the relationship between terms.

The Registry is comprised of two primary sections; a preferences component where users can specify their language preferences, and a 'browse | search' component for exploring the registry contents. Each of these components is described in more detail in the following sections.

I. Language Preferences
1.1 User Interface Language
1.2 Metadata Language
II. Browsing The Registry
III. Searching The Registry
3.1 Understanding Results
IV. Multilingual Issues
V. Application Interface
5.1 Registry REST Application Interface
5.2 Registry SOAP Application Interface
VI. Acknowledgements

I. Language Preferences

The language preference component enables users to customize their environment by offering them a choice of user interface language and result-set language. Click on the 'Language preference' link found on the 'Browse | Search' screen.

1.1 User Interface Language

This option is used to select from a list of available user interface languages.

1.2 Metadata Language

The 'Display Results In' option is used to select the language for displaying metadata results. Select from the list of available languages.

Figure 1: Selecting language preferences

II. Browsing The Registry

The browse component provides a number of pre-generated queries that can be selected from a drop-down box. These can be used to display summary listings of:

Figure 2: Browse interface

Clicking on any of the items in the summary listing will generate a query for that particular item.

III. Searching The Registry

Text Searching

The search form enables users to search for metadata that matches specific words or phrases. The form supports both case-sensitive and case-insensitive searching and enables users to restrict their search to terms that match:

Figure 3: Search interface

3.1 Understanding Results

Query results are produced by clicking on one of the items returned from a text search, or included in a summary display. The query results include all of the known properties for that item. These can include both text literals and resources. Resources are displayed as hyperlinks that either resolve to that resource definition, or that generate a new query for that particular resource. for example, a query result-set that included the term 'title' would produce a display similar to:

Figure 4: Item detail

Each of the resources in the result-set above are displayed as hyperlinks that provide the user with a simple means to navigate between terms and their relationships. Clicking on any of the property labels (i.e., Label, Definition, Description, etc.) would resolve to the definition of that resource. Likewise, clicking on 'Property' would resolve to the definition of a 'property'. However, clicking on resources known locally to the Registry (such as 'http://purl.org/dc/elements/1.1/' and 'alternative') would generate a new query for that particular resource. This is true for all resources that are displayed. Users can quickly differentiate between these two types of links by their 'hover' color. This is the color a link changes to when the mouse (or other pointing device) is placed over the link. Local links are displayed in blue and remote links in green. For example, clicking on alternative in the above result-set would generate a new query with the following results:

Figure 5: Navigating relationships between terms

IV. Miltilingual Issues

The language preference information (selected on the preferences screen) is stored as a 'cookie' on the client session. This requires that cookies be enabled on your browser. This is the default setting for both IE and Netscape. Cookies are not required to use the Registry, but they are required to view the language translations.

User interface and term translations are encoded in UTF-8 encoding. Set your browser's character coding to 'Unicode - UTF8' to display the translations. You may also require additional fonts for some languages. Newer versions of many browsers include support for this. It is recommended that you use a recent release of your browser. For example: Netscape 6.2 (or higher) or Internet Explorer 5.5 (or higher).

The Dublin Core elements and qualifiers have been translated in dozens of languages and the Registry provides support for many of these. However, there is only one official (or canonical) definition for a term. For this reason, all items in result-sets that are displayed in languages other than their 'official' translation will include a 'quick-link' option that enables users to quickly compare the 'canonical' version to the translated version. Click on the Canonical Translation link to view the canonical translation of an item.

Term translations are made by translating the label, definition and (optional) comment fields for each term. Additional information is associated with each translated property. This includes a description and right-management properties, and when available, a creator, date, publisher and source properties. This is accomplished by providing a link to this information next to each translation.

For example: the following is displayed for the German translation of the term 'title':

Figure 6: Accessing provenance for term translations

Clicking on the [ de-DE ] links will display provenance information about that translation.

V. Application Interface

The Registry application interface provides information about the Registry contents in a format that is suitable for applications and other registries. This is accomplished thru a collection of Web services, collectively known as the Registry application interface. The two principal approaches to Web services are SOAP and REST. The Registry currently supports both approaches. Each of the services will return results in RDF/XML format that can be parsed by applications. Each approach is described below, along with information regarding how to use each service.

5.1 Registry REST Application Interface

The REpresentational State Transfer (REST) approach uses URLs to identify resources, which are then accessed using simple HTTP GET and POST requests. The RESTwiki site is a great source of information about REST. The remainder of this section describes the REST style services and how to invoke them.

http://dublincore.org/dcregistry/listItemSummary
Summary: This service returns a list of all resources that are registered.
Parameters: No input parameters are required.
Sample Call: http://dublincore.org/dcregistry/listItemSummary

http://dublincore.org/dcregistry/listSupportedLanguages
Summary: This service returns a list of all supported languages.
Parameters: No input parameters are required.
Sample Call: http://dublincore.org/dcregistry/listSupportedLanguages

http://dublincore.org/dcregistry/listItemDetail
Summary: This service returns all known information about a resource in a requested language.
Parameters: A resource name (i.g., http://purl.org/dc/elements/1.1/creator) and a (optional) language code (i.g., en-US). Note that omitting the language code will return detail about the requested item in all supported languages.
Sample Call: http://dublincore.org/dcregistry/listItemDetail?item=http://purl.org/dc/elements/1.1/creator&lang=en-US

http://dublincore.org/dcregistry/getUpdates
Summary: This service returns a list of all changes to the Registry, in a specific language, since a specific date.
Parameters: This interface requires a date and a language (i.g., 20021015 en-US).
Sample Call: http://dublincore.org/dcregistry/getUpdates?date=20030101&lang=en-US

http://dublincore.org/dcregistry/listElements
Summary: This service returns a list of all registered elements.
Parameters: No input parameters are required.
Sample Call: http://dublincore.org/dcregistry/listElements

http://dublincore.org/dcregistry/listElementRefinements
Summary: This service returns a list of all registered element refinements.
Parameters: No input parameters are required.
Sample Call: http://dublincore.org/dcregistry/listElementRefinements

http://dublincore.org/dcregistry/listVocabularyTerms
Summary: This service returns a list of all registered controlled vocabulary terms.
Parameters: No input parameters are required.
Sample Call: http://dublincore.org/dcregistry/listVocabularyTerms

http://dublincore.org/dcregistry/listEncodingSchemes
Summary: This service returns a list of all registered encoding schemes.
Parameters: No input parameters are required.
Sample Call: http://dublincore.org/dcregistry/listEncodingSchemes

5.2 Registry SOAP Application Interface

The Registry SOAP application interface is a collection of Web services that were developed with the Apache Axis toolkit. The available services are listed below. Each of these services publishes Web Services Description Language (WSDL), which provides a degree of platform and language neutrality to the service. The WSDL can be used by a growing number of tools, such as Mind Electric's GLUE and Alphaworks Web Services Toolkit, to automatically generate client code with which to access the service. Sample client code, generated using GLUE, for the itemSummary and itemDetail services, can be found here. Clients for the remaining services can easily be modeled from the itemSummary and itemDetail examples.

Service discovery is an important aspect of Web services. The Web Services Inspection Language (WSIL) is a distributed discovery mechanism that provides references to service descriptions. WSIL documents are XML documents which rely on conventions, not only for specifying the service description syntax, but also for specifying the name and location within a Web site that should be inspected for service descriptions.

The DCMI Registry follows these conventions by providing a WSIL service desctiption document at the following address: http://dublincore.org/services/inspection.wsil. Sample source code which demonstrates how to read and use a WSIL document can be found here.

ItemSummary
This service returns a list of all resources that are registered. No input parameters are required. The WSDL for this service can be found at: http://dublincore.org/axis/services/itemSummary?wsdl

ItemDetail
This interface requires a resource name (i.g., http://purl.org/dc/elements/1.1/creator) and a language code (i.g., en-US). It returns all known information about the resource in the requested language. The WSDL for this service can be found at: http://dublincore.org/axis/services/itemDetail?wsdl

encodingSchemesSummary
This service returns a list of all registered encoding schemes. No input parameters are required. http://dublincore.org/axis/services/encodingSchemesSummary?wsdl

refinementsSummary
This service returns a list of all registered element refinements. No input parameters are required. The WSDL for this service can be found at: http://dublincore.org/axis/services/refinementsSummary?wsdl

termUpdates
This service returns a list of all changes to the Registry, in a specific language, since a specific date. This interface requires a date and a language (i.g., 20021015 en-US). The WSDL for this service can be found at: http://dublincore.org/axis/services/termUpdates?wsdl

vocabularyTermsSummary
This service returns a list of all registered controlled vocabulary terms. No input parameters are required. The WSDL for this service can be found at: http://dublincore.org/axis/services/vocabularyTermsSummary?wsdl

languagesSummary
This service returns a list of all supported languages. No input parameters are required. The WSDL for this service can be found at: http://dublincore.org/axis/services/languagesSummary?wsdl

elementSummary
This service returns a list of all registered elements. No input parameters are required. The WSDL for this service can be found at: http://dublincore.org/axis/services/elementSummary?wsdl

 

VI. Acknowledgements

The Dublin Core Metadata Initiative and the DCMI Registry Working Group would like to express their appreciation to the following volunteers who have contributed their time, ideas, expertise and support in the development of this application:

Antonio Alba, OCLC
Leif Andresen, Danish National Library Authority
Thomas Baker, Institutszentrum Schloss Birlinghoven, Sankt Augustin, Germany
Miroslav Bartosek, MU v Brně - Ústav výpočetní techniky, Czech Republic
Maria Bruna Baldacci, Istituto di Elaborazione dell'Informazione, Italy
Ольга Барышева (Olga Barysheva), The National Library of Russia
Biblioteca de Catalunya, Spain
José Luis Borbinha, Biblioteca Nacional, Portugal
Marcela Calderon, Universidad de Chile
陳雪華 (Dr. Hsueh-hua Chen), National Taiwan University
Yong Cho, OCLC
Lyn Lewis Dafis, Llyfrgell Genedlaethol Cymru (National Library of Wales)
Stina Degerstedt, National Library of Sweden
Makx Dekkers, DCMI
طارق أسامة المراغي (Tarik Osama El-Maraghy)
Stefan Farrenkopf, State and University Library at Göettingen, Germany
Thomas Fischer, State and University Library at Göettingen, Germany
Juha Hakala, Helsinki University Library, Finland
Dr. Hachim Haddouti, Arabic
Frank B. Haugen, Den norske katalogkomité, Norway
Баньківська Ірина (Bankovskay Irina), Lesya Ukrainka Public Library
Istituto Centrale per il Catalogo Unico delle Biblioteche Italiane e per le Informazioni Bibliografiche - ICCU, Italy
Pete Johnston, UKOLN
鞠放 (Fang Ju), OCLC, USA
Σαράντος Καπιδάκης (Sarantos Kapidakis), Ionian University, Greece
Traugott Koch, NetLab Lund University Libraries, Sweden
Javi Masa Marin, RedIRIS. Edificio CICA, Spain
Maria Moreno, Spain
永森光晴 (Mitsuharu Nagamori), University of Library and Information Science, Japan
शुभदा नगरकर (Shubhada Nagarkar), Bioinformatics Centre, University of Pune, India
Marek Nahotko, Energoprojekt - Kraków S.A., Poland
Heike Neuroth, State and University Library at Göettingen, Germany
오삼균 (Dr. Sam-Gyun Oh), SungKyunKwan University, Korea
Lawrence Olszewski, OCLC
Shaochun Ouyang, OCLC
Hubert Padiou, France
สิทธิพร ประภาวัต (Sittiporn Prabhavat), Technical Information Access Center - TIAC, Thailand
Karen Rollitt, National Library of New Zealand Te Puna Mātauranga o Aotearoa
Diann Rusch-Feja, Max-Planck-Institut für Bildungsforschung, Germany
Kanya Saengswang, OCLC
Світлана Санжак(Svetlana Sanzhak), Lesya Ukrainka Public Library
Roland Schwäenzl, Universität Osnabrück, Germany
ประดิษฐา ศิริพันธ์ (Praditta Siripan), Technical Information Access Center - TIAC, Thailand
Jani Stenvall, Helsinki University Library, Finland
杉本重雄 (Shigeo Sugimoto), University of Library and Information Science, Japan
Carol van Nuys, Den norske katalogkomité, Norway
Anne-Marie.Vercoustre, Inria Rocquencourt, France
Herve de Villemeur, France
Ганна Воскресенська (Hanna Voskresenska), National Parliamentary Library of Ukraine
Liu Wei, Shanghai Library
Petr Zabicka, MU v Brně - Ústav výpočetní techniky, Czech Republic
Klaus Zaepke, State and University Library at Göettingen, Germany