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DCMI Guidelines for Dublin Core Application Profiles - Overview
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These contents have been obtained from the DCMI official Web site and edited for presentation. Please refer to the DCMI Web site for additional information on terms of use.
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Dublin Core Metadata Initiative
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When it comes to metadata, one size does not fit all. In fact, one size often does not even fit many. The metadata needs of particular communities and applications are very diverse. The result is a great proliferation of metadata formats, even across applications that have metadata needs in common. The Dublin Core Metadata Initiative has addressed this by providing a framework for designing a Dublin Core Application Profile (DCAP). A DCAP defines metadata records which meet specific application needs while providing semantic interoperability with other applications on the basis of globally defined vocabularies and models.
Note that a DCAP is a generic construct for designing metadata records that does not require the use of metadata terms defined by DCMI. A DCAP can use any terms that are defined on the basis of RDF, combining terms from multiple namespaces as needed. A DCAP follows the DCMI Abstract Model, a generic model for metadata records.
A DCAP includes guidance for metadata creators and clear specifications for metadata developers. By articulating what is intended and can be expected from data, application profiles promote the sharing and linking of data within and between communities. The resulting metadata will integrate with a semantic web of linked data. To achieve this it is recommended that application profiles be developed by a team with specialized knowledge of the resources that need to be described, the metadata to be used in the description of those resources, as well as an understanding of the Semantic Web and the linked data environment.
The interoperability of DCAP-based metadata in linked data environments derives from its basis in standards:- Resource Description Framework (RDF), the foundation standard on which domain standards rest,
- the Dublin Core Abstract Model, a generic syntax for metadata records,
- the Dublin Core Description Set Profile, a constraint language for Application Profiles
- DCMI guidelines for implementation encodings.
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| NOTE: The Dublin Core Education Community is developing an DC-Education Application Profile (DC-Ed AP) intended to describe a precise category of "things in the world" that have been deliberately purposed (or re-purposed) for use in the processes of formal and informal teaching and learning. The DC-Ed AP is limited to defining use of properties describing the educational characteristics of a resource. Properties describing general descriptive attributes of a resource or properties describing use of a resource in contexts other than teaching and learning, are outside the scope of the application profile. |
Terms of use
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These contents have been obtained from the DCMI official Web site and edited for presentation. Please refer to the DCMI Web site for additional information on terms of use.
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A DCAP is a document (or set of documents) that specifies and describes the metadata used in a particular application. To accomplish this, a profile:- describes what a community wants to accomplish with its application (Functional Requirements);
- characterizes the types of things described by the metadata and their relationships (Domain Model);
- enumerates the metadata terms to be used and the rules for their use (Description Set Profile and Usage Guidelines); and
- defines the machine syntax that will be used to encode the data (Syntax Guidelines and Data Formats).
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How these standards fit together is illustrated in the Singapore Framework for Dublin Core Application Profiles. The bottom tier, RDF, provides the foundation standards on which domain standards are built. The middle tier defines domain standards that provide structural and semantic stability for Application Profiles. The upper tier holds the design and documentation components of specific metadata applications.
Singapore Framework
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Taking the upper tier of the Singapore Framework as a roadmap, the "DCMI Guidelines for Dublin Core Application Profiles" document walk through the process of creating a DCAP.
- Defining Functional requirements: Functional requirements guide the development of the application profile by providing goals and boundaries and are an essential component of a successful application profile development process. There are methodologies to help in the creation of functional requirements, such as business process modeling, and methods for visualizing requirements, such as the Unified Modeling Language. Some find that the definition of use cases and scenarios for a particular application helps elicit functional requirements that might otherwise be overlooked.
- Selecting or Developing a Domain model: After defining functional requirements, the next step is to select or develop a domain model. A domain model is a description of what things your metadata will describe, and the relationships between those things. The domain model is the basic blueprint for the construction of the application profile.
- Selecting or Defining Metadata Terms: After we have defined the domain model for our metadata, we need to choose properties for describing the things in that model. The next step, then, is to scan available RDF vocabularies to see whether the properties needed have already been declared and are available for use. Using existing properties, when appropriate, requires less effort and increases the interoperability of your metadata. If the properties one needs are not already available, it is possible to declare one's own.
- Designing the Metadata Record with a Description Set Profile: The next step is to describe the metadata record in detail. In the DCMI approach, a metadata record is based on the Description Set Model (itself part of the DCMI Abstract Model), and the record's design is detailed in a Description Set Profile (or DSP) using a DSP constraint language. For each Description and Statement in a record, the DSP defines a template, and each template holds relevant constraints specifying technical details such as the repeatability of elements or restrictions on allowable values.
- Usage Guidelines: A Description Set Profile defines the "what" of the application profile; usage guidelines provide the "how" and "why". Usage guidelines offer instructions to those who will create the metadata records. Ideally, they explain each property and anticipate the decisions that must be made in the course of creating a metadata record. Documentation for metadata creators presents some of the same information that is included in the DSP, but in a more human-understandable form. Those inputting metadata will need to know: is this property required? is it repeatable? am I limited in the values that I can use with the property? Oftentimes a user interface can answer these questions, for example by presenting the metadata creator with a list of valid values from which to choose.
- Syntax Guidelines: To help developers turn their application profiles into functioning software applications, DCMI has developed various encoding guidelines. Description Set Profiles can be deployed using any concrete implementation syntax for which a mapping to the abstract model has been specified. DCMI has developed or is developing guidelines for encoding DCAM-based metadata in HTML/XHTML, XML, and RDF/XML; others could be added in the future. There is no restriction on use of other types of syntax as long as the resulting data format is compatible with the foundation standards and with the DCMI Abstract Model.
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Terms of use
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These contents have been obtained from the DCMI official Web site and edited for presentation. Please refer to the DCMI Web site for additional information on terms of use.
Print
Title: Guidelines for Dublin Core Application Profiles
Version: Not applicable
Release Date: 18 May 2009
Creators: Karen Coyle, Thomas Baker
Status: DCMI Recommended Resource
Electronic version: Available in html format. |
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