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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
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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


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