Dublin Core Workshop Series S. Weibel Internet-Draft J. Kunze draft-kunze-dc-01.txt C. Lagoze 27 August 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 weibel@oclc.org, or to the discussion list meta2@mrrl.lut.ac.uk. 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 HTML 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. In the element descriptions below, a formal single-word label is specified to make the syntactic specification of elements simpler for encoding schemes. Each element is optional and repeatable. 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 schemas 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 The date the resource was made available in its present form. Recommended best practice is an 8 digit number in the form YYYY-MM-DD as defined in [2], a profile of ISO 8601. In this scheme, the date element 1994-11-05 corresponds to November 5, 1994. Many other schema are possible, but if used, they should be identified in an unambiguous manner. 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 under development in the workshop series at the time of publication of this draft. 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 under development in the workshop series at the time of publication of this draft. 3.10. Resource Identifier Label: IDENTIFIER 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 A string or number used to uniquely identify the work from which this resource was derived, if applicable. For example, a PDF version of the novel ``Gone with the Wind'' might have a SOURCE element containing an ISBN number for the physical book from which the PDF version was derived. 3.12. Language Label: LANGUAGE Language(s) of the intellectual content of the resource. Where practical, the content of this field should coincide with the NISO Z39.53 three character codes for written languages. 3.13. Relation (experimental) Label: RELATION The relationship of this resource to other resources. The intent of this element is to provide a means to express relationships among resources that have formal relationships to others, but exist as discrete resources themselves. For example, images in a document, chapters in a book, or items in a collection. Formal specification of RELATION is currently under development. Users and developers should understand that use of this element is currently considered to be experimental. 3.14. Coverage (experimental) Label: COVERAGE The spatial and/or temporal characteristics of the resource. Formal specification of COVERAGE is currently under development. Users and developers should understand that use of this element is currently considered to be experimental. 3.15. Rights Management (experimental) Label: RIGHTS A link to a copyright notice, to a rights-management statement, or to a service that would provide information about terms of access to the resource. Formal specification of RIGHTS is currently under development. Users and developers should understand that use of this element is currently considered to be experimental. 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 7. Authors' Addresses Stuart L. Weibel OCLC Online Computer Library Center, Inc. Office of Research 6565 Frantz Rd. Dublin, Ohio, 43017, USA Email: weibel@oclc.org 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: jak@ckm.ucsf.edu 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: lagoze@cs.cornell.edu Voice: +1-607-255-6046 Fax: +1-607-255-4428