Title: DC Subject and Description Working Group Review of RFC2413

Date: 1999-03-08

Status: Report to DC Technical Advisory Group

New defintions for Subject and Description. The main changes are:

• Adoption of ISO 11179 representation
• Separation of "Definition" from "Comment"
• Ensuring definitions are not self-referential i.e. not allowing inclusion of the defined term in the definition. So in the Subject definition use of 'topic' rather than 'subject'; in the Description definition use of 'account' rather than 'description'.
• Broadening the definitions to ensure they are not overly focused on textual data:
  • removing 'textual' from the definition of description (was 'textual description')
  • adding non-text example in comment on description (graphical representation)

Proposed Definitions

  Name:        Subject and Keywords
  Identifier:  Subject
  Definition:  The topic of the resource
  Obligation:  Optional
  Datatype:    Character String
  Maximum
  Occurrence:  Unlimited
  Comment:     Typically, subject will be expressed as keywords,
               phrases or classmarks that describe the topic of the resource.
               The use of controlled vocabularies and formal classification
               schemes is encouraged.

  Name:        Description
  Identifier:  Description
  Definition:  An account of the content of the resource
  Obligation:  Optional
  Datatype:    Character String; Binary string
  Maximum
  Occurrence:  Unlimited
  Comment:     The Description may include, but is not limited to: abstract,
               table of contents, graphical representation of content,or a free-text 
	       account of content.													account of the content.
		

Issues List

1. It was suggested that ISO11179 is more suited to describing how metadata is used in a particular implementation rather than for providing 'the canonical definition'. Individual implementations may have limits on obligation, datatypes and maximum occurrence which differ from the canonical definition. Implementors may want to express these implementation specific limits in ISO11179 format too. How will such representations be identified?
2. There is a need to produce an overall statement of the advantages of using ISO 11179 for the DC community. The debate on the pros and cons of ISO 11179 needs to take place in a wider forum than the WG's.
3. It would be useful to have a list of datatypes which might be used e.g. is a classmark a character string? what datatype is a graphical representation? I have assumed all are character strings except 'graphical representation' for which I have added 'binary string'. But maybe as there would always be a level of indirection if a value was a graphical representation (where the data element contains a URL pointing to a graphical representation) then the datatype should be character string as the content is a URL?

Existing RFC-2413 Definitions

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.

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.

Contact the DC Subject and Description Working Group at: http://purl.org/DC/groups/subdesc.htm