Please review this new draft of the Dublin Core element descriptions.
It's been revised in accordance with understandings reached in Helsinki
and is ready for discussion and comments on the meta2 list.
The aim is to iron out details (the Finnish Finish?) of the basic element
semantics, publish a new Internet-Draft, and issue a final call for
comments before forwarding it to the Internet Engineering Steering Group
(IESG) with a recommendation to publish it as an internet informational RFC.
-John
PS. There were too many small changes for a "diffs" file (detailing the
differences) to be meaningful, but all changes were in sections 2.5 and 3.
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
John A. Kunze +1 415-502-6660 Mgr, Advanced Tech Group
530 Parnassus Ave, Box 0840 [log in to unmask] Library and Center for
San Francisco, CA 94143-0840 Fax: 415-476-4653 Knowledge Management
=-=-=-=-=-=-=-= University of California, San Francisco =-=-=-=-=-=-=-=
Dublin Core Workshop Series S. Weibel
Internet-Draft J. Kunze
draft-kunze-dc-02.txt C. Lagoze
27 October 1997
Expires in six months
Dublin Core Metadata for Simple Resource Discovery
1. Status of this Document
This document is an Internet-Draft. Internet-Drafts are working
documents of the Internet Engineering Task Force (IETF), its areas, and
its working groups. Note that other groups may also distribute working
documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as ``work in progress.''
To learn the current status of any Internet-Draft, please check the
``1id-abstracts.txt'' listing contained in the Internet-Drafts Shadow
Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe),
munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or
ftp.isi.edu (US West Coast).
Distribution of this document is unlimited. Please send comments
to [log in to unmask], or to the discussion list [log in to unmask]
2. Introduction
Finding relevant information on the World Wide Web has become
increasingly problematic in proportion 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.
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
- 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 additional qualification of elements for some applications.
Thus, Dublin Core elements may be expressed in simple unqualified ways
that minimal discovery and retrieval tools can use, or they may be
expressed with additional structure to support semantics-sharpening
qualifiers that minimal tools can safely ignore but that more complex
tools can employ to increase discovery precision.
The broad agreements about syntax and semantics that have emerged from
the workshop series will be expressed in a series of five Informational
RFCs, of which this document is the first. These RFCs (currently they
are Internet-Drafts) will comprise the following documents.
2.1. Dublin Core Metadata for Simple Resource Discovery
An introduction to the Dublin Core and a description of the intended
semantics of the 15-element Dublin Core element set without qualifiers.
This is the present document.
2.2. Encoding Dublin Core Metadata in HTML
A formal description of the convention for embedding unqualified Dublin
Core metadata in HTML.
2.3. Qualified Dublin Core Metadata for Simple Resource Discovery
The principles of element qualification and the semantics of Dublin Core
metadata when expressed with a recommended qualifier set known as the
Canberra Qualifiers.
2.4. Encoding Qualified Dublin Core Metadata in HTML
A formal description of the convention for embedding qualified Dublin
Core metadata in HTML.
2.5. Dublin Core on the Web: RDF Compliance and DC Extensions
A formal description for encoding Dublin Core metadata with qualifiers
in RDF compliant metadata, and how to extend the core element set.
3. Description of Dublin Core Elements
The following is the reference definition of the Dublin Core Metadata
Element Set. It is expected that practice will evolve to include
qualifiers for certain of the elements. The reference description of
the elements resides at [1]:
http://purl.org/metadata/dublin_core_elements
Note that elements have a descriptive name intended to convey a common
semantic understanding of the element. 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. Further note that each element is optional and repeatable.
In the element descriptions below, a formal single-word label is specified
to make the syntactic specification of elements simpler for encoding schemes.
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 names given below to avoid conflicts in the event that the metadata
is subsequently converted to a case-sensitive environment, such as XML/RDF.
3.1. Title Label: "Title"
The name given to the resource by the Creator or Publisher.
3.2. 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.
3.3. 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.
3.4. 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.
3.5. 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.
3.6. 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).
3.7. Date Label: "Date"
A date associated with the creation or availability of the resource.
Such a date is not to be confused with one belonging in the Coverage
element, which would be associated with the resource only insofar as
the intellectual content is somehow about that date. Recommended
best practice is defined in a profile of ISO 8601 [2] 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.
3.8. 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.
3.9. Format Label: "Format"
The data format of the resource, used to identify the software
and possibly hardware that might be needed to display or operate
the resource. For the sake of interoperability, Format should be
selected from an enumerated list that is currently under development
in the workshop series.
3.10. 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.
3.11. Source Label: "Source"
Information about a second resource from which this resource is
derived. This element may contain a date, format, identifier, or
other information pertaining to the second resource. This element
is not applicable for a resource that appears in its original form.
It may be desirable to have a separate metadata package for the
second resource; in that case, use of the Relation element is
recommended.
3.12. Language Label: "Language"
The language of the intellectual content of the resource.
Where practical, the content of this field should coincide with
RFC 1766 [3]; examples include en, de, es, fi, fr, ja, th, and zh.
3.13. Relation Label: "Relation"
An identifier of a second resource and its relationship to this
resource. This element is a means of linking separate metadata
packages of related resources. Examples include a translation of
a work, a chapter of a book, or a mechanical transformation.
For the sake of interoperability, relationships should be selected
from an enumerated list that is currently under development in the
workshop series.
3.14. Coverage Label: "Coverage"
The spatial and/or temporal characteristics of the intellectual content
of the resource. Any date in this element is concerned with what the
resource is about rather than when it was created or made available, the
latter belonging in the Date element. Formal specification of Coverage
is currently under development.
3.15. Rights Management Label: "Rights"
A rights management statement, an identifier that links to a
rights management statement, or an identifier that links a service
providing information about rights management for the resource.
4. 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
simple Dublin Core scheme. No other security concerns are likely
to be raised by the element description consensus documented here.
5. References
[1] Dublin Core Metadata Element Set: Reference Description,
http://purl.org/metadata/dublin_core_elements
[2] ISO 8601 Profile for the Dublin Core,
http://purl.org/metadata/dublin_core_date_formats
[3] RFC 1766, Tags for the Identification of Languages,
http://ds.internic.net/rfc/rfc1766.txt language tags
7. Authors' Addresses
Stuart L. Weibel
OCLC Online Computer Library Center, Inc.
Office of Research
6565 Frantz Rd.
Dublin, Ohio, 43017, USA
Email: [log in to unmask]
Voice: +1 614-764-6081
Fax: +1 614-764-2344
John A. Kunze
Center for Knowledge Management
University of California, San Francisco
530 Parnassus Ave, Box 0840
San Francisco, CA 94143-0840, USA
Email: [log in to unmask]
Voice: +1 415-502-6660
Fax: +1 415-476-4653
Carl Lagoze
Digital Library Research Group
Department of Computer Science
Cornell University
Ithaca, NY 14853, USA
Email: [log in to unmask]
Voice: +1-607-255-6046
Fax: +1-607-255-4428
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