Appendix 2. Explanation of Terminology

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Certain terminology has been applied throughout this report.  Short explanations are provided below. 

Metadata Terms  and Properties

“[metadata] elements”,  “[metadata] fields”, and “attributes [of an entity]” have been widely used by the professionals who are involved in creating, designing, and implementing metadata standards. In a number of metadata structure standards it is the term “elements” that have dominated in the specifications. Some standards (e.g., those used by library, museum, and archives communities) prepared their data structure standards (e.g., MODS, CDWA, VRA Core 4, EAD) using XML schema as the primary medium. 

These specifications modelled the structure with a set of “elements” and sub-elements, related “attributes”, and controlled “attribute values” throughout the element sets.  Nevertheless, as represented by DCMI Metadata Terms (DCTERMS), the RDF terminology instead of the XML terminology is now gaining momentum.  The term “properties” of resources are used in place of “elements” in this report. LODE-BD considers the process of metadata description as the description of properties of a resource. For example, ‘rights’ is considered as a property of a resource. 

Property:                                rights

Because there are various levels of granularity and several corresponding ways that this property can be described, LODE-BD uses “metadata term” for a specific element formally defined by a metadata namespace. For example, property ‘rights’   can be described by metadata terms from different namespaces:

                    Metadata term:                    dc:rights

                    Metadata term:                    dcterms:rights

 

String and URI as values

In the LODE-BD Recommendations, the words ‘string’ and ‘URI’ are used for the most commonly seen values in bibliographic data.  They correspond to the terminology of RDF in the form of ‘literal’ (typically a string of characters) and ‘non-literal’.    

Literal: “The most primitive value type represented in RDF, typically a string of characters. The content of a literal is not interpreted by RDF itself and may contain additional XML markup. Literals are distinguished from Resources in that the RDF model does not permit literals to be the subject of a statement.”[1]

Non-literal value: “A value which is a physical, digital or conceptual entity.”[2]

For example, “rice” is a concept included in the AGROVOC Thesaurus, with a preferred label (in English),  “Rice.” When the thesaurus is published as Linked Data, the concept is considered as a resource and is given a unique URI,  http://aims.fao.org/aos/agrovoc/c_6599.  This means that a URI reference is used to identify this concept as a resource.

In this situation for the property: subject, the metadata terms for encoding this property include dc:subject and dcterms:subject.  Because dcterms:subject “is intended to be used with non-literal values as defined in the DCMI Abstract Model (http://dublincore.org/documents/abstract-model/)”,[3] the value to be used associated with this metadata term should be the URI http://aims.fao.org/aos/agrovoc/c_6599 which represents the concept as a resource instead of “Rice” or other language labels of the concept. 

Based on the definition of these metadata terms, the following examples are provided:

Metadata Term

Value Type

Example

dc:subject 

String

Rice

dcterms:subject

URI

http://aims.fao.org/aos/agrovoc/c_6599

[Bibliographic] Resource

The term “Resource” is used in the conceptual model to denote a general entity, the Bibliographic Resource.  An instance of the bibliographic resource can be an article, monograph, thesis, conference paper, research report, presentation material, learning object, etc., regardless if it is in print or electronic format.  In the flowcharts provided by the LODE-BD Recommendations, the ‘resource’ at the beginning oval box is an instance of the Bibliographic Resource.   


[1] Resource Description Framework (RDF) Model and Syntax Specification (1999-02-22). Glossary for this source http://www.w3.org/2003/glossary/keyword/All/literal.html?keywords=literal Last accessed February 2011  

[2] DCMI Abstract Model.  http://www.dublincore.org/documents/abstract-model/  Last accessed February 2011

[3] DC Terms. http://dublincore.org/documents/dcmi-terms/#terms-subject Last accessed May 28, 2012.

 

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