The Semantic Web activity is a W3C project whose goal is to enable a 'cooperative' Web where machines and humans can exchange electronic content that has clear-cut, unambiguous meaning. This vision is based on the automated sharing of metadata terms across Web applications. The declaration of schemas in metadata registries advance this vision by providing a common approach for the discovery, understanding, and exchange of semantics. However, many of the issues regarding registries are not clear, and ideas vary regarding their scope and purpose. Additionally, registry issues are often difficult to describe and comprehend without a working example.
ISBN
1082-9873
Critical Arguements
CA "This article will explore the role of metadata registries and will describe three prototypes, written by the Dublin Core Metadata Initiative. The article will outline how the prototypes are being used to demonstrate and evaluate application scope, functional requirements, and technology solutions for metadata registries."
Phrases
<P1> Establishing a common approach for the exchange and re-use of data across the Web would be a major step towards achieving the vision of the Semantic Web. <warrant> <P2> The Semantic Web Activity statement articulates this vision as: 'having data on the Web defined and linked in a way that it can be used for more effective discovery, automation, integration, and reuse across various applications. The Web can reach its full potential if it becomes a place where data can be shared and processed by automated tools as well as by people.' <P3> In parallel with the growth of content on the Web, there have been increases in the amount and variety of metadata to manipulate this content. An inordinate amount of standards-making activity focuses on metadata schemas (also referred to as vocabularies or data element sets), and yet significant differences in schemas remain. <P4> Different domains typically require differentiation in the complexity and semantics of the schemas they use. Indeed, individual implementations often specify local usage, thereby introducing local terms to metadata schemas specified by standards-making bodies. Such differentiation undermines interoperability between systems. <P5> This situation highlights a growing need for access by users to in-depth information about metadata schemas and particular extensions or variations to schemas. Currently, these 'users' are human  people requesting information. <warrant> <P6> It would be helpful to make available easy access to schemas already in use to provide both humans and software with comprehensive, accurate and authoritative information. <warrant> <P7> The W3C Resource Description Framework (RDF) has provided the basis for a common approach to declaring schemas in use. At present the RDF Schema (RDFS) specification offers the basis for a simple declaration of schema. <P8> Even as it stands, an increasing number of initiatives are using RDFS to 'publish' their schemas. <P9> Registries provide 'added value' to users by indexing schemas relevant to a particular 'domain' or 'community of use' and by simplifying the navigation of terms by enabling multiple schemas to be accessed from one view. <warrant> <P10> Additionally, the establishment of registries to index terms actively being used in local implementations facilitates the metadata standards activity by providing implementation experience transferable to the standards-making process. <warrant> <P11> The overriding goal has been the development of a generic registry tool useful for registry applications in general, not just useful for the DCMI. <P12> The formulation of a 'definitive' set of RDF schemas within the DCMI that can serve as the recommended, comprehensive and accurate expression of the DCMI vocabulary has hindered the development of the DCMI registry. To some extent, this has been due to the changing nature of the RDF Schema specification and its W3C candidate recommendation status. However, it should be recognized that the lack of consensus within the DCMI community regarding the RDF schemas has proven to be equally as impeding. <P13> The automated sharing of metadata across applications is an important part of realizing the goal of the Semantic Web. Users and applications need practical solutions for discovering and sharing semantics. Schema registries provide a viable means of achieving this. <warrant>
Conclusions
RQ "Many of the issues regarding metadata registries are unclear and ideas regarding their scope and purpose vary. Additionally, registry issues are often difficult to describe and comprehend without a working example. The DCMI makes use of rapid prototyping to help solve these problems. Prototyping is a process of quickly developing sample applications that can then be used to demonstrate and evaluate functionality and technology."
SOW
DC "New impetus for the development of registries has come with the development activities surrounding creation of the Semantic Web. The motivation for establishing registries arises from domain and standardization communities, and from the knowledge management community." ... "The original charter for the DCMI Registry Working Group was to establish a metadata registry to support the activity of the DCMI. The aim was to enable the registration, discovery, and navigation of semantics defined by the DCMI, in order to provide an authoritative source of information regarding the DCMI vocabulary. Emphasis was placed on promoting the use of the Dublin Core and supporting the management of change and evolution of the DCMI vocabulary." ... "Discussions within the DCMI Registry Working Group (held primarily on the group's mailing list) have produced draft documents regarding application scope and functionality. These discussions and draft documents have been the basis for the development of registry prototypes and continue to play a central role in the iterative process of prototyping and feedback." ... The overall goal of the DCMI Registry Working Group (WG) is to provide a focus for continued development of the DCMI Metadata Registry. The WG will provide a forum for discussing registry-related activities and facilitating cooperation with the ISO 11179 community, the Semantic Web, and other related initiatives on issues of common interest and relevance.
