ISO/IEC JTC 1/SC 34N0884

ISO/IEC JTC 1/SC 34

Information Technology --
Document Description and Processing Languages

TITLE:	Draft Expressing Dublin Core Metadata Using Topic Maps
SOURCE:	Mr. Steve Pepper; Mr. Motomu Naito; Mr. Patrick Durusau
PROJECT:	WD 29111: Information Technology - Topic Maps - Expressing Dublin Core Metadata using Topic Maps
PROJECT EDITOR:	Dr. Sam Gyun Oh; Mr. Steve Pepper
STATUS:	Draft
ACTION:	Review in preparation for WG3 meeting
DATE:	2007-07-04
DISTRIBUTION:	SC34 and Liaisons
REPLY TO:	Dr. James David Mason (ISO/IEC JTC 1/SC 34 Chairman) Y-12 National Security Complex Bldg. 9113, M.S. 8208 Oak Ridge, TN 37831-8208 U.S.A. Telephone: +1 865 574-6973 Facsimile: +1 865 574-1896 Network: masonjd@y12.doe.gov http://www.y12.doe.gov/sgml/sc34/ ftp://ftp.y12.doe.gov/pub/sgml/sc34/ Mr. G. Ken Holman (ISO/IEC JTC 1/SC 34 Secretariat - Standards Council of Canada) Crane Softwrights Ltd. Box 266, Kars, ON K0A-2E0 CANADA Telephone: +1 613 489-0999 Facsimile: +1 613 489-0995 Network: jtc1sc34@scc.ca http://www.jtc1sc34.org

ISO/IEC PDTR 29111: Information Technology – Topic Maps

Expressing Dublin Core Metadata Using Topic Maps

Working Draft, 2007-06-25

Authors: Steve Pepper, Sam Oh, Patrick Durusau

0. Scope

The Dublin Core Metadata Initiative (DCMI) has produced one of the most successful vocabularies for expressing document metadata and is in widespread use on the World Wide Web, in libraries, and in many other areas. DCMI vocabularies are defined as sets of abstract elements and terms; the syntactic expression of these elements and terms is technology dependent.

This Technical Report defines a standard way of expressing Dublin Core metadata using ISO/IEC 13250 Topic Maps. Its purpose is to ensure a uniform approach to the application of Dublin Core among users of Topic Maps and thus enable seamless integration and improved knowledge aggregation. It covers both the general case of expressing Dublin Core metadata sets and the specific case of assigning Dublin Core metadata to topic maps, i.e., to topic maps viewed as what Dublin Core calls “described resources”.

All four term sets described in [DCMT] are covered, i.e., the Dublin Core Metadata Element Set, Other Elements and Element Refinements, Encoding Schemes, and the DCMI Type Vocabulary.

1. Normative references

[13250-2]

ISO/IEC 13250-2:2006 Topic Maps – Data Model

[15836]

ISO 15836: 2003 Information and documentation – The Dublin Core metadata element set

[DCAM]

DCMI Abstract Model, 2007-06-04, http://dublincore.org/documents/abstract-model/

[DCMT]

DCMI Metadata Terms, 2006-12-18, http://dublincore.org/documents/dcmi-terms/

2. Definitions

For the purposes of this Technical Report the definitions given in ISO/IEC 13250-2 apply.

The following terms defined in [DCAM] are reproduced here for convenience:

property

A specific aspect, characteristic, attribute, or relation used to describe resources.

property/value pair

The combination of a property and a value, used to describe a characteristic of a resource.

resource

Anything that might be identified. Familiar examples include an electronic document, an image, a service (for example, "today's weather report for Los Angeles"), and a collection of other resources. Not all resources are network "retrievable"; for example, human beings, corporations, concepts and bound books in a library can also be considered resources.

syntax encoding scheme

A set of strings and an associated set of rules that describe a mapping between that set of strings and a set of resources. The mapping rules may define how the string is structured (for example DCMI Box) or they may simply enumerate all the strings and the corresponding resources (for example ISO 3166).

value

The physical entity, conceptual entity or literal (a resource) that is associated with a property when a property-value pair is used to describe a resource.

value string

A literal, optionally associated with either a syntax encoding scheme URI or a value string language. In a literal value surrogate a value string encodes the value; in a non-literal value surrogate a value string represents the value.

value string language

An ISO language tag that indicates the language of the value string.

vocabulary encoding scheme

An enumerated set of resources.

3. The DCAM and the TMDM

This Clause describes basic equivalences between the Dublin Core Abstract Model and the Topic Maps Data Model and how concepts are mapped from the one to the other.

3.1 General principles

For the purpose of this Technical Report, a resource in Dublin Core is deemed to be equivalent to a subject in Topic Maps.

The assignment of metadata in the form of property-value pairs to Dublin Core resources is deemed to be the equivalent of making statements about a subject in Topic Maps.

Associations are used to represent property-value pairs whenever possible, which is to say in all cases except those case of:

1. elements that are naming properties (which are represented as topic names);

2. elements whose values consist of descriptive text or structured data types (which are represented as occurrences).

All such associations are binary and use the following pair of role types:

• Role played by the described resource: http://psi.topicmaps.org/iso29111/resource

• Role played by the resource that is the value of the property-value pair: http://psi.topicmaps.org/iso29111/value

When assigning Dublin Core metadata to a topic map, the topic map must first be reified. Statements are then made about the resulting topic.

3.2 Mapping the concepts of the DCAM

[DCAM] describes models for resources described by descriptions and for metadata description sets. The concepts of these models are mapped to concepts of the Topic Maps Data Model as follows:

• A DC described resource is represented by a topic item.

• A DC property-value pair is represented by a Topic Maps statement (i.e., a name item, occurrence item or association item, as specified in Clause 4).

• The property of a DC property-value pair is represented by the [type] property of the statement to which it gives rise.

• The value of a DC property-value pair is represented either by a topic item or by the [value] property of a name or occurrence item, as specified in Clause 4.

• A DC vocabulary encoding scheme or syntax encoding scheme is represented by the [datatype] property of an occurrence item.

• A DC value string language is represented by a [scope] property that consists of a single topic representing the language in question.

4. Dublin Core Metadata Terms

This Clause specifies the Topic Maps representation of every element and term in [DCMT].

4.1 The Dublin Core Metadata Element Set

The following table shows the kind of Topic Maps construct to which each term in the Dublin Core Metadata Element Set should be mapped. The prefix dc is used to represent the URI http://purl.org/dc/elements/1.1/.

4.2 Other Elements and Element Refinements

The following table shows the kind of Topic Maps construct to which each term in the metadata set Other Elements and Element Refinements should be mapped. The prefix dct is used to represent the URI http://purl.org/dc/terms/.

4.3 Encoding Schemes

Each term in the metadata set Encoding Schemes is represented by a topic whose subject identifier is the same as the URI of the term in question.

4.4 The DCMI Type Vocabulary

Each term in the metadata set DCMI Type Vocabulary is represented by a topic whose subject identifier is the same as the URI of the term in question.