DCMI-compliant 'term' decision tree

Andy Powell
UKOLN, University of Bath
July 2005

This decision tree can be used to see if something is a DCMI-compliant element, element refinement or encoding scheme, where "DCMI-compliant" means conformant with the DCMI Abstract Model and therefore suitable for use in DC metadata descriptions.

Note that in the following text, the italicised terms are defined in the terminology section below.

Decision tree

1. Has the thing been explicitly declared as a DCMI element (i.e. as a property)?
   The declaration may take the form of a human-readable statement, e.g.

   X is an 'element' as defined in the DCMI Abstract Model
   

   or as a machine-readable RDFS declaration

   <rdf:Property rdf:about="http://example.org/term/X">
     ...
   </rdf:Property>
   

   • If 'yes', go to question 2.
   • Otherwise, go to question 3.
2. Are the expected values of the element resources that have been assigned 'value URIs' or that can be represented using simple 'value strings' (plain text strings)?
   • If 'yes', go to question 9.
   • Otherwise, go to question 3.
3. Has the thing been explicitly declared as a DCMI element refinement (i.e. as a property)?
   The declaration may take the form of a human-readable statement, e.g.

   X is an 'element refinement' as defined in the DCMI Abstract Model
   

   or as a machine-readable RDFS declaration

   <rdf:Property rdf:about="http://example.org/term/X">
     ...
   </rdf:Property>
   

   • If 'yes', go to question 4.
   • Otherwise, go to question 5.
4. Are the expected values of the element refinement resources that have been assigned 'value URIs' or that can be represented using simple 'value strings' (plain text strings)?
   • If 'yes', go to question 9.
   • Otherwise, go to question 5.
5. Has the thing been explicitly declared as a DCMI syntax encoding scheme?
   The declaration may take the form of a human-readable statement, e.g.

   X is a 'syntax encoding scheme' as defined in the DCMI Abstract Model
   

   or as a machine-readable RDFS declaration

   <rdf:Description rdf:about="http://example.org/term/X">
     <dc:type rdf:resource="http://dublincore.org/usage/documents/principles/#syntax-encoding-scheme"/>
     ...
   </rdf:Description>
   

   • If 'yes', go to question 6.
   • Otherwise, go to question 7.
6. Are all the valid values according to the syntax encoding scheme simple 'value strings' (plain text strings)?
   • If 'yes', go to question 9.
   • Otherwise, go to question 7.
7. Has the thing been explicitly declared as a DCMI vocabulary encoding scheme?
   The declaration may take the form of a human-readable statement, e.g.

   X is a 'vocabulary encoding scheme' as defined in the DCMI Abstract Model
   

   or as a machine-readable RDFS declaration

   <rdfs:Class rdf:about="http://example.org/term/X">
      ...
   </rdfs:Class>
   

   • If 'yes', go to question 9.
   • Otherwise, the thing is not a valid DCMI element, element refinement or encoding scheme.
8. Are all the valid members of the vocabulary encoding scheme resources that have been assigned 'value URIs' or that can be represented using simple 'value strings' (plain text strings)?
   • If 'yes', go to question 9.
   • Otherwise, the thing is not a valid DCMI element, element refinement or encoding scheme.
9. Has the thing been assigned a URI (a property URI or an encoding scheme URI)?
   For example: http://example.org/term/X
   • If 'yes', the thing is a valid DCMI element, element refinement or encoding scheme.
   • Otherwise, the thing is not a valid DCMI element, element refinement or encoding scheme.

Note

The exact details of the RDF declarations about are not fully agreed. The examples used here are based on the current DCMI RDF declarations, with a little modification. The author suggests that the 'term type' URIs used here (e.g. http://dublincore.org/usage/documents/principles/#vocabulary-encoding-scheme) need to be changed.

Terminology

class

A group containing members that have attributes, behaviours, relationships or semantics in common; a kind of category.

class URI

A URI that identifies a class.

element

A property of a resource.

element refinement

A property of a resource that shares the meaning of a particular DCMI property but with narrower semantics. Since element refinements are properties, they can be used in metadata descriptions independently of the properties they refine. In DCMI practice, an element refinement refines just one parent DCMI property.

encoding scheme

A vocabulary encoding scheme or a syntax encoding scheme.

encoding scheme URI

A vocabulary encoding scheme URI or a syntax encoding scheme URI.

property

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

property URI

A URI that identifies a single property.

syntax encoding scheme

A syntax encoding scheme indicates that the value string is formatted in accordance with a formal notation, such as "2000-01-01" as the standard expression of a date.

syntax encoding scheme URI

A URI that identifies a syntax encoding scheme. For all DCMI recommended encoding schemes, the URI is constructed by concatenating the name of the encoding scheme with the http://purl.org/dc/terms/ namespace URI.

term

A property (i.e. element or element refinement), vocabulary encoding scheme, syntax encoding scheme or concept taken from a controlled vocabulary (concept space).

term URI

A URI that identifies a term.

vocabulary encoding scheme

A class that indicates that the value of a property is taken from a controlled vocabulary (or concept-space), such as the Library of Congress Subject Headings.

vocabulary encoding scheme URI

A URI that identifies a vocabulary encoding scheme. For all DCMI recommended encoding schemes, the URI is constructed by concatenating the name of the encoding scheme with the http://purl.org/dc/terms/ namespace URI.