Internet-Draft R. Iannella draft-iannella-admin-00.txt DSTC 08 September 1998 D. Campbell Expires in six months NLA Admin Core - Administrative Container Metadata 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 view the entire list of current Internet-Drafts, please check the "1id-abstracts.txt" listing contained in the Internet-Drafts Shadow Directories on ftp.is.co.za (Africa), ftp.nordu.net (Northern Europe), ftp.nis.garr.it (Southern Europe), munnari.oz.au (Pacific Rim), ftp.ietf.org (US East Coast), or ftp.isi.edu (US West Coast). Distribution of this document is unlimited. Please send comments to <renato@dstc.edu.au> and <dcampbel@nla.gov.au>. 2. Introduction Administrative metadata - referred to as 'Admin Core' - is useful to designate information about the creation and availability of other sets of metadata. The objective of Admin Core is to provide simple authentication to verify the integrity and provenance of information retrieved from networked resources. The Admin Core elements are utilised to associate date and creator information about metadata. It is important to recognise that Admin Core is a "container" metadata element set as opposed to a "content" metadata element set - its purpose is to describe metadata instances. The Admin Core, as with other metadata elements sets, is a "core" set. That is, it is extensible by allowing the addition of new elements that are specific to a community's needs. This is similar to the model presented by the Dublin Core Metadata Element Set [2]. Admin Core is not useful by itself. It must be used in association with at least one other metadata element set. For example, Dublin Core [2], or Privacy [3] metadata. This amalgamation of different metadata sets is supported by a number of metadata encoding systems, such as the Resource Description Framework [1] and the HTML META tag [6]. Examples are given in Section 5. Admin Core metadata will be used by systems and users to determine the currency of metadata, expired metadata, and how to contact creators of metadata. 3. Description of Admin Core Elements The following is the reference definition of the Admin Core Metadata Element Set. The evolving reference description can be found at: http://metadata.net/admin 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. The recommended best practice is to be case-sensitive to avoid complications in case-sensitive environments such as RDF [1]. The element descriptions also indicate the obligations, encoding, and repeatability characteristics for each Admin Core element in accordance with the ISO Standard 11179 [8]. 3.1 Personal Creator Name: CreatorPersonal Definition: The person responsible for creating or modifying the metadata pertaining to a resource. Obligation: Conditional. Either "Personal Creator" or "Corporate Creator" element must appear, or both. Datatype: Character String Maximum Occurrence: Unlimited Comment: If possible, the comma (,) is used to separate the surname first followed by firstname. For example; "Crystal, Mary" 3.2 Corporate Creator Name: CreatorCorporate Definition: The name of the organisation by which the metadata creator is employed. Obligation: Conditional. Either "Personal Creator" or "Corporate Creator" element must appear or both. Datatype: Character String Maximum Occurrence: Unlimited Comment: The organisation may be a trusted third party for the source of the metadata. The organisation is not necessarily the entity making the resource available. 3.3 Creator Email Address Name: CreatorEmail Definition: The email address of the metadata Creator. Obligation: Mandatory Datatype: Character String. Encoded to be consistent with Internet Address standard RFC822 [7] Maximum Occurrence: Unlimited. Comment: None 3.4 Creator Contact Information Name: CreatorContact Definition: Information on how to contact the creator. Obligation: Optional Datatype: Character String Maximum Occurrence: Unlimited Comment: The information should be one or more of: a street or postal address, a telephone number, a facsimile number, and the homepage address of the creator. This provides additional evidence for the existence of a trusted third party. 3.5 Date Created Name: DateCreated Definition: The date/time the metadata was created by the Personal or Corporate Creator. Obligation: Mandatory Datatype: Character String. Encoded to Date and Time Format ISO 8601 [4] Maximum Occurrence: Unlimited Comment: None 3.6 Date Modified Name: DateModified Definition: The date/time the metadata was most recently modified by the Personal or Corporate Creator. Obligation: Optional Datatype: Character String. Encoded to Date and Time Format ISO 8601 [4]. Maximum Occurrence: Unlimited Comment: None 3.7 Date Valid From Name: DateValidFrom Definition: The commencing date of the validity of the metadata description. Obligation: Conditional. Single occurrence only is permissible otherwise must appear in pairs with "Date Valid To" element. Datatype: Character String. Encoded to Date and Time Format ISO 8601 [4]. Maximum Occurrence: Unlimited Comment: Non-administrative metadata accessed before this date should be considered to be invalid. 3.8 Date Valid To Name: DateValidTo Definition: The end date of the validity of the metadata description. Obligation: Conditional. Single occurrence only is permissible otherwise must appear in pairs with "Date Valid From" element. Datatype: Character String. Encoded to Date and Time Format ISO 8601 [4]. Maximum Occurrence: Unlimited. Comment: Non-administrative metadata accessed after this date should be considered to be invalid. 4. Internationalisation All the Admin Core elements can be associated with language information using RFC 1766 [5]. The Admin Core labels are used in the communication of metadata between systems, with human-readable names being available in multiple languages for client systems. 5. Admin Core Examples 5.1 HTML META Syntax Below is an example of the use of the Admin Core metadata elements with the bibliographic style Dublin Core metadata elements. This example shows the HTML META syntax [6]. Admin Core elements will be assigned the namespace of "ADMIN" for the META tag syntax encodings. <META NAME="DC.Title" LANG="en" CONTENT="Admin Core Metadata Element Specification"> <META NAME="DC.Creator" LANG="en" CONTENT="Crystal, Jacky"> <META NAME="DC.Date" SCHEME="ISO8601" LANG="en" CONTENT="1998-01-01"> <META NAME="DC.Identifier" SCHEME="URI" LANG="en" CONTENT="http://metadata.net/ADMIN/elements.html"> <META NAME="ADMIN.CreatorPersonal" LANG="en" CONTENT="Rubble, Barney"> <META NAME="ADMIN.CreatorEmail" LANG="en" CONTENT="barn@metadata.net"> <META NAME="ADMIN.DateCreated" SCHEME="ISO8601" CONTENT="1998-01-15"> 5.2 RDF/XML Syntax Below is another example of the use of Admin Core metadata elements with the bibliographic style Dublin Core metadata elements. This example shows the use of RDF syntax [1]. The RDF XML Namespace for Admin Core will be defined as: <http://metadata.net/admin/#> <? xml version="1.0" ?> <RDF xmlns = "http://www.w3.org/TR/WD-rdf-syntax#" xmlns:DC = "http://metadata.net/dc/#" xmlns:ADMIN = "http://metadata.net/admin/#" > <Description xml:lang="en" about = "http://metadata.net/admin/elements.html"> <DC:Title> Admin Core Metadata Element Specification </DC:Title> <DC:Creator> Crystal, Jacky </DC:Creator> <DC:Date> 1998-01-01 </DC:Date> <ADMIN:CreatorCorporate> Rubble Corp <ADMIN:CreatorCorporate> <ADMIN:CreatorEmail> info@rubble.com </ADMIN:CreatorEmail> <ADMIN:DateCreated> 1998-01-15 </ADMIN:DateCreated> <ADMIN:DateValidFrom> 1998-02-01 </ADMIN:DateValidFrom> <ADMIN:DateValidTo > 1999-02-01 </ADMIN:DateValidTo> </Description> </RDF> 6. Security Considerations The Admin Core element set poses no risk to computers and networks. Human clients who obtain metadata that has been incorrectly described (by humans) may face minimal risk in determining the correctness of the metadata. The application of Digital Signature technology is recommended by systems requiring high levels of authentication. 7. Acknowledgements The work reported in this paper has been funded in part by the Cooperative Research Centres Program through the Department of the Prime Minister and Cabinet of Australia and from the National Priority (Reserve) Fund allocation for Improved Library Infrastructure administered by the AV-CC Standing Committee on Information Resources. 8. References [1] Resource Description Framework (RDF) Model and Syntax <http://www.w3.org/TR/WD-rdf-syntax> [2] RFC 2413, Dublin Core Metadata for Resource Discovery <ftp://ftp.isi.edu/in-notes/rfc2413.txt> [3] Platform for Privacy Preferences Metadata <http://www.w3.org/P3P> [4] Date and Time Formats (based on ISO 8601), W3C Technical Note <http://www.w3.org/TR/NOTE-datetime> [5] RFC 1766, Tags for the Identification of Languages <ftp://ftp.isi.edu/in-notes/rfc1766.txt> [6] A Proposed Convention for Embedding Metadata in HTML <http://purl.oclc.org/docs/metadata/dublin_core/approach.html> [7] RFC822 Standard for the Format of ARPA Internet Text Messages <ftp://ftp.isi.edu/in-notes/rfc822.txt> [8] ISO 11179 Parts 1-6, Specification and Standardization of Data Elements <ftp://sdct-sunsrv1.ncsl.nist.gov/x3l8/11179/> 9. Authors' Addresses Renato Iannella DSTC Pty Ltd The University of Queensland Qld, 4072, AUSTRALIA Email: renato@dstc.edu.au Voice: +61 7 3365 4310 Fax: +61 7 3365 4311 Debbie Campbell National Library of Australia Canberra ACT, 2600, AUSTRALIA Email: dcampbel@nla.gov.au Voice: +61 2 6262 1673 Fax: +61 2 6273 4535