Dublin+Core

= Dublin Core = toc The **Dublin Core** metadata terms are a set of vocabulary terms which can be used to describe resources for the purposes of discovery. The terms can be used to describe a full range of web resources: video, images, web pages etc and physical resources such as books and objects like artworks. The full set of Dublin Core metadata terms can be found on the [|Dublin Core Metatdata Initiative (DCMI) website]. The original set of 15 classic metadata terms, known as the Dublin Core Metadata Element Set are endorsed in the following standards documents:
 * IETF RFC 5013
 * ISO Standard 15836-2009
 * NISO Standard Z39.85

Dublin Core Metadata can be used for multiple purposes, from simple resource description, to combining metadata vocabularies of different metadata standards, to providing interoperability for metadata vocabularies in the linked data cloud and semantic web implementations.

History and Development
"Dublin" refers to Dublin, Ohio, where the work originated during the 1995 invitational OCLC/NCSA Metadata Workshop, hosted by Online Computer Library Center (OCLC) and the National Center for Supercomputing Applications (NCSA). "Core" refers to the metadata terms as "broad and generic being usable for describing a wide range of resources." The semantics of Dublin Core were established and are maintained by an international, cross-disciplinary group of professionals from librarianship, computer science, text encoding , museums, and other related fields of scholarship and practice. The Dublin Core Metadata Initiative ( DCMI ) incorporated as an independent entity, separating from OCLC, in 2008 that provides an open forum for the development of interoperable online metadata standards for a broad range of purposes and of business models. DCMI's activities include consensus-driven working groups, global conferences and workshops, standards liaison, and educational efforts to promote widespread acceptance of metadata standards and practices.

Dublin Core levels of standardization
The Dublin Core standard includes two levels — Simple and Qualified. **Simple Dublin Core** comprises 15 elements; **Qualified Dublin Core** includes three additional elements;— Audience, Provenance and RightsHolder;— as well as a group of element refinements, also called qualifiers, that refine the semantics of the elements in ways that may be useful in resource discovery.

Simple Dublin Core
The Simple **Dublin Core Metadata Element Set (DCMES)** consists of 15 metadata elements:
 * 1) Title
 * 2) Creator
 * 3) Subject
 * 4) Description
 * 5) Publisher
 * 6) Contributor
 * 7) Date
 * 8) Type
 * 9) Format
 * 10) Identifier
 * 11) Source
 * 12) Language
 * 13) Relation
 * 14) Coverage
 * 15) Rights

Each Dublin Core element is optional and may be repeated. The DCMI has established standard ways to refine elements and encourage the use of encoding and vocabulary schemes. There is no prescribed order in Dublin Core for presenting or using the elements. Full information on element definitions and term relationships can be found in the [|Dublin Core Metadata Registry].


 * Example of code **

Qualified Dublin Core
Subsequent to the specification of the original 15 elements, an ongoing process to develop exemplary terms extending or refining the Dublin Core Metadata Element Set (DCMES) was begun. The additional terms were identified, generally in working groups of the Dublin Core Metadata Initiative, and judged by the DCMI Usage Board to be in conformance with principles of good practice for the qualification of Dublin Core metadata elements. Elements refinements make the meaning of an element narrower or more specific. A refined element shares the meaning of the unqualified element, but with a more restricted scope. The guiding principle for the qualification of Dublin Core elements, colloquially known as the //Dumb-Down Principle,// states that an application that does not understand a specific element refinement term should be able to ignore the qualifier and treat the metadata value as if it were an unqualified (broader) element. While this may result in some loss of specificity, the remaining element value (without the qualifier) should continue to be generally correct and useful for discovery. In addition to element refinements, Qualified Dublin Core includes a set of recommended encoding schemes, designed to aid in the interpretation of an element value. These schemes include controlled vocabularies and formal notations or parsing rules. A value expressed using an encoding scheme may thus be a token selected from a controlled vocabulary or a string formatted in accordance with a formal notation, for example, "2000-12-31" as the ISO standard expression of a date. If an encoding scheme is not understood by an application, the value may still be useful to the human reader. **Audience, Provenance** and **RightsHolder** are elements, but not part of the Simple Dublin Core 15 elements. Use Audience, Provenance and RightsHolder only when using Qualified Dublin Core. DCMI also maintains a small, general vocabulary recommended for use within the element Type. This vocabulary currently consists of 12 terms.