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- Network Working Group S. Weibel
- Request for Comments: 2413 OCLC Online Computer Library Center, Inc.
- Category: Informational J. Kunze
- University of California, San Francisco
- C. Lagoze
- Cornell University
- M. Wolf
- Reuters Limited
- September 1998
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- Dublin Core Metadata for Resource Discovery
-
- 1. Status of this Memo
-
- This memo provides information for the Internet community. It does
- not specify an Internet standard of any kind. Distribution of this
- memo is unlimited.
-
- Copyright Notice
-
- Copyright (C) The Internet Society (1998). All Rights Reserved.
-
- 2. Abstract
-
- The Dublin Core Metadata Workshop Series began in 1995 with an
- invitational workshop which brought together librarians, digital
- library researchers, content experts, and text-markup experts to
- promote better discovery standards for electronic resources. The
- Dublin Core is a 15-element set of descriptors that has emerged from
- this effort in interdisciplinary and international consensus
- building. This is the first of a set of Informational RFCs
- describing the Dublin Core. Its purpose is to introduce the Dublin
- Core and to describe the consensus reached on the semantics of each
- of the 15 elements.
-
- 3. Introduction
-
- Finding relevant information on the World Wide Web has become
- increasingly problematic due to the explosive growth of networked
- resources. Current Web indexing evolved rapidly to fill the demand
- for resource discovery tools, but that indexing, while useful, is a
- poor substitute for richer varieties of resource description.
-
- An invitational workshop held in March of 1995 brought together
- librarians, digital library researchers, and text-markup specialists
- to address the problem of resource discovery for networked resources.
-
-
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- Weibel, et. al. Informational [Page 1]
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- RFC 2413 Dublin Core Metadata for Resource Discovery September 1998
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- This activity evolved into a series of related workshops and
- ancillary activities that have become known collectively as the
- Dublin Core Metadata Workshop Series.
-
- The goals that motivate the Dublin Core effort are:
-
- - Simplicity of creation and maintenance
- - Commonly understood semantics
- - Conformance to existing and emerging standards
- - International scope and applicability
- - Extensibility
- - Interoperability among collections and indexing systems
-
- These requirements work at cross purposes to some degree, but all are
- desirable goals. Much of the effort of the Workshop Series has been
- directed at minimizing the tensions among these goals.
-
- One of the primary deliverables of this effort is a set of elements
- that are judged by the collective participants of these workshops to
- be the core elements for cross-disciplinary resource discovery. The
- term "Dublin Core" applies to this core of descriptive elements.
-
- Early experience with Dublin Core deployment has made clear the need
- to support qualification of elements for some applications. Thus, a
- Dublin Core element may be expressed without qualification (as
- described in this RFC) or with qualifiers that refine its semantics
- (the subject of future RFCs). For the sake of interoperability,
- simple indexing and discovery tools should be able to ignore any
- qualifiers provided, while more advanced, semantically richer tools
- should be able to use qualifiers to support more specialized or
- precise discovery.
-
- The broad agreements about syntax and semantics that have emerged
- from the workshop series will be expressed in a series of
- Informational RFCs, of which this document is the first.
-
- 4. Description of Dublin Core Elements
-
- The following is the reference definition of the Dublin Core Metadata
- Element Set. Further information about the Dublin Core Metadata
- Element Set is available at [1]:
-
- http://purl.org/metadata/dublin_core
-
- In the element descriptions below, each element has a descriptive
- name intended to convey a common semantic understanding of the
- element, as well as a formal single-word label intended to make the
- syntactic specification of elements simpler for encoding schemes.
-
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- Weibel, et. al. Informational [Page 2]
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- RFC 2413 Dublin Core Metadata for Resource Discovery September 1998
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- Although some environments, such as HTML, are not case-sensitive, it
- is recommended best practice always to adhere to the case conventions
- in the element labels given below to avoid conflicts in the event
- that the metadata is subsequently extracted or converted to a case-
- sensitive environment, such as XML (Extensible Markup Language) [2].
-
- Each element is optional and repeatable. Metadata elements may
- appear in any order. The ordering of multiple occurrences of the
- same element (e.g., Creator) may have a significance intended by the
- provider, but ordering is not guaranteed to be preserved in every
- system.
-
- To promote global interoperability, a number of the element
- descriptions suggest a controlled vocabulary for the respective
- element values. It is assumed that other controlled vocabularies
- will be developed for interoperability within certain local domains.
-
- The metadata elements fall into three groups which roughly indicate
- the class or scope of information stored in them: (1) elements
- related mainly to the Content of the resource, (2) elements related
- mainly to the resource when viewed as Intellectual Property, and (3)
- elements related mainly to the Instantiation of the resource.
-
- Content Intellectual Property Instantiation
- ----------- --------------------- -------------
- Title Creator Date
- Subject Publisher Format
- Description Contributor Identifier
- Type Rights Language
- Source
- Relation
- Coverage
-
- 4.1. Title Label: "Title"
-
- The name given to the resource, usually by the Creator or Publisher.
-
- 4.2. Author or Creator Label: "Creator"
-
- The person or organization primarily responsible for creating the
- intellectual content of the resource. For example, authors in the
- case of written documents, artists, photographers, or illustrators in
- the case of visual resources.
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- RFC 2413 Dublin Core Metadata for Resource Discovery September 1998
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- 4.3. Subject and Keywords Label: "Subject"
-
- The topic of the resource. Typically, subject will be expressed as
- keywords or phrases that describe the subject or content of the
- resource. The use of controlled vocabularies and formal
- classification schemes is encouraged.
-
- 4.4. Description Label: "Description"
-
- A textual description of the content of the resource, including
- abstracts in the case of document-like objects or content
- descriptions in the case of visual resources.
-
- 4.5. Publisher Label: "Publisher"
-
- The entity responsible for making the resource available in its
- present form, such as a publishing house, a university department, or
- a corporate entity.
-
- 4.6. Other Contributor Label: "Contributor"
-
- A person or organization not specified in a Creator element who has
- made significant intellectual contributions to the resource but whose
- contribution is secondary to any person or organization specified in
- a Creator element (for example, editor, transcriber, and
- illustrator).
-
- 4.7. Date Label: "Date"
-
- A date associated with the creation or availability of the resource.
- Recommended best practice is defined in a profile of ISO 8601 [3]
- that includes (among others) dates of the forms YYYY and YYYY-MM-DD.
- In this scheme, for example, the date 1994-11-05 corresponds to
- November 5, 1994.
-
- 4.8. Resource Type Label: "Type"
-
- The category of the resource, such as home page, novel, poem, working
- paper, technical report, essay, dictionary. For the sake of
- interoperability, Type should be selected from an enumerated list
- that is currently under development in the workshop series.
-
- 4.9. Format Label: "Format"
-
- The data format and, optionally, dimensions (e.g., size, duration) of
- the resource. The format is used to identify the software and
- possibly hardware that might be needed to display or operate the
-
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- Weibel, et. al. Informational [Page 4]
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- RFC 2413 Dublin Core Metadata for Resource Discovery September 1998
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- resource. For the sake of interoperability, the format should be
- selected from an enumerated list that is currently under development
- in the workshop series.
-
- 4.10. Resource Identifier Label: "Identifier"
-
- A string or number used to uniquely identify the resource. Examples
- for networked resources include URLs and URNs (when implemented).
- Other globally-unique identifiers, such as International Standard
- Book Numbers (ISBN) or other formal names are also candidates for
- this element.
-
- 4.11. Source Label: "Source"
-
- Information about a second resource from which the present resource
- is derived. While it is generally recommended that elements contain
- information about the present resource only, this element may contain
- metadata for the second resource when it is considered important for
- discovery of the present resource.
-
- 4.12. Language Label: "Language"
-
- The language of the intellectual content of the resource.
- Recommended best practice is defined in RFC 1766 [4].
-
- 4.13. Relation Label: "Relation"
-
- An identifier of a second resource and its relationship to the
- present resource. This element is used to express linkages among
- related resources. For the sake of interoperability, relationships
- should be selected from an enumerated list that is currently under
- development in the workshop series.
-
- 4.14. Coverage Label: "Coverage"
-
- The spatial or temporal characteristics of the intellectual content
- of the resource. Spatial coverage refers to a physical region (e.g.,
- celestial sector) using place names or coordinates (e.g., longitude
- and latitude). Temporal coverage refers to what the resource is
- about rather than when it was created or made available (the latter
- belonging in the Date element). Temporal coverage is typically
- specified using named time periods (e.g., neolithic) or the same
- date/time format [3] as recommended for the Date element.
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- Weibel, et. al. Informational [Page 5]
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- RFC 2413 Dublin Core Metadata for Resource Discovery September 1998
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- 4.15. Rights Management Label: "Rights"
-
- A rights management statement, an identifier that links to a rights
- management statement, or an identifier that links to a service
- providing information about rights management for the resource.
-
- 5. Security Considerations
-
- The Dublin Core element set poses no risk to computers and networks.
- It poses minimal risk to searchers who obtain incorrect or private
- information due to careless mapping from rich data descriptions to
- the simple Dublin Core scheme. No other security concerns are likely
- to be raised by the element description consensus documented here.
-
- 6. References
-
- [1] Further information about the Dublin Core Metadata Element Set,
- http://purl.org/metadata/dublin_core
-
- [2] Extensible Markup Language (XML), http://www.w3.org/TR/REC-xml
-
- [3] Date and Time Formats (based on ISO 8601), W3C Technical Note,
- http://www.w3.org/TR/NOTE-datetime
-
- [4] Alvestrand, H., "Tags for the Identification of Languages", RFC
- 1766, March 1995.
-
- 7. Authors' Addresses
-
- Stuart L. Weibel
- OCLC Online Computer Library Center, Inc.
- Office of Research
- 6565 Frantz Rd.
- Dublin, Ohio, 43017, USA
-
- Phone: +1 614-764-6081
- Fax: +1 614-764-2344
- EMail: weibel@oclc.org
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- Weibel, et. al. Informational [Page 6]
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- RFC 2413 Dublin Core Metadata for Resource Discovery September 1998
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- John A. Kunze
- Center for Knowledge Management
- University of California, San Francisco
- 530 Parnassus Ave, Box 0840
- San Francisco, CA 94143-0840, USA
-
- Phone: +1 510-525-8575
- Fax: +1 415-476-4653
- EMail: jak@ckm.ucsf.edu
-
-
- Carl Lagoze
- University Library and Department of Computer Science
- Cornell University
- Ithaca, NY 14853, USA
-
- Phone: +1 607-255-6046
- Fax: +1 607-255-4428
- EMail: lagoze@cs.cornell.edu
-
-
- Misha Wolf
- Reuters Limited
- 85 Fleet Street
- London EC4P 4AJ, UK
-
- Phone: +44 171-542-6722
- Fax: +44 171-542-8314
- EMail: misha.wolf@reuters.com
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- Weibel, et. al. Informational [Page 7]
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- RFC 2413 Dublin Core Metadata for Resource Discovery September 1998
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- 8. Full Copyright Statement
-
- Copyright (C) The Internet Society (1998). All Rights Reserved.
-
- This document and translations of it may be copied and furnished to
- others, and derivative works that comment on or otherwise explain it
- or assist in its implementation may be prepared, copied, published
- and distributed, in whole or in part, without restriction of any
- kind, provided that the above copyright notice and this paragraph are
- included on all such copies and derivative works. However, this
- document itself may not be modified in any way, such as by removing
- the copyright notice or references to the Internet Society or other
- Internet organizations, except as needed for the purpose of
- developing Internet standards in which case the procedures for
- copyrights defined in the Internet Standards process must be
- followed, or as required to translate it into languages other than
- English.
-
- The limited permissions granted above are perpetual and will not be
- revoked by the Internet Society or its successors or assigns.
-
- This document and the information contained herein is provided on an
- "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
- TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
- BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
- HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
- MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
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