|DCMI Registry Community|
|Dublin Core Metadata Initiative|
Definitions, viewpoints and use cases
Purpose of this page
Every registry development is situated in a unique set of circumstances and thinking. This page is to be used to collect a few perspectives. These might include anything from statement of fact or position to formal use cases (see the Use Cases section on this page).
Anything from attributed quotes to structured description is fine on this page.
Definitions and viewpoints
"Vocabularies are sets of terms used to tag documents. Their use increases both precision and recall of searching. At the simplest level, all Flickr terms form a vocabulary. Richer vocabularies have semantics and structure. Thesauri, taxonomies, ontologies, authority lists and control lists are all more or less the same thing as vocabularies (purists will hate me for saying that). -- Mike Taylor on the Becta VMS
"Creating vocabularies is a pain. Tools are expensive." -- Mike Taylor on the Becta VMS
- "namespace schemas declare (name and define) data elements;
- application profiles describe the use of (previously declared) data elements to meet the requirements of a particular context or application.
A metadata application profile may
- select elements from multiple namespaces (but must not use elements that are not previously declared in a namespace schema);
- refine the definitions of elements by making them narrower or more specific;
- specify constraints on the permitted values of elements by mandating the use of particular controlled vocabularies or formats" Pete Johnston
"What is an application profile? Application profiles consist of data elements drawn from one or more namespace schemas combined together by implementors and optimised for a particular local application." http://www.ariadne.ac.uk/issue25/app-profiles/
"The registry is intended to serve as a discovery mechanism and resolution service, with the goal of promoting the reuse of existing terminologies represented in multiple languages. ... Each of the communities these registries serve is comprised of:
- Read-only users. These include both the humans and applications that are the primary consumers of the registry content. Additionally, the read-only users provide feedback to the registration authority regarding change requests to the registry content.
- A registration authority, responsible for approving registry content. For example, the DCMI Usage Board is the registration authority for the registry available at the Dublin Core Web site. The Usage Board evaluates proposed new terms that are suggested by the larger Dublin Core community. Approved terms are then passed to the registry steward for inclusion in the metadata registry.
- Stewards are responsible for application support and maintenance. Their role is limited to the development, support and ongoing maintenance of the registry software. They rely on the registration authority for decisions regarding the actual registry content." -- Wagner & Weibel, The Dublin Core Metadata Registry: Requirements, Implementation, and Experience. Journal of Digital Information, Volume 6 Issue 2, 2005
"Two main ways to use a vocabulary: 1) Visible to the user. Can be browsed to find suitable search terms. 2) Behind the scenes: non-preferred terms mapped to preferred terms or synonyms expanded ... can include expansion to broader and narrower terms, or translated terms." -- Mike Taylor on the Becta VMS
"The services offered by a metadata schema registry may cover many different functions, and different metadata schema registries may provide different sets of functions depending on their purpose, scope and context; those functions might include:
1. Disclosure/discovery of information about metadata terms
2. Disclosure/discovery of relationships between metadata terms
3. Mapping or inferencing services based on relationships between terms
4. Verification of the provenance or status of metadata terms
5. Disclosure/discovery of related resources (such as functional aggregations of terms, guidelines for use, bindings for metadata instances, etc)" -- Pete Johnston