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1、TEL Milestone Conference 29 - 30 April 2002Die Deutsche Bibliothek Frankfurt am Main, GermanyRachel Heery, UKOLN, University of BathApplication profiles: interoperable friend or foe?Delivered by Michael Day at: The European Library (TEL) - The Gate to Europes Knowledge: Milestone Conference, Die Deu
2、tsche Bibliothek Frankfurt am Main, Germany. AbstractMetadata application profiles provide a simple model to articulate local adaptations of standard schemas and to specify encoding schemes in use in particular implementations. Declaring and sharing such profiles is a positive step towards interoper
3、ability enabling the re-use of existing schemas, and the identification of new terms. The SCHEMAS registry provides an overview of application profiles alongside standard schemas. In this presentation we will consider the extra effort that is required to ensure that declaration of application profil
4、es contributes the interoperability agenda. How might we deal with new metadata terms to avoid duplication within multiple schemas, where are the means to capture emergent semantics? How can standards making bodies work together to harmonise metadata usage? What is our role as implementers and infor
5、mation professionals?TEL is concerned with sharing metadata across a number of organisations. In my presentation to day, I would like to consider what is involved in sharing metadata, in particular the sharing of metadata schemas, and think a little about the processes involved.TerminologyFirst we w
6、ill try to establish shared understanding of terms, although it has to be acknowledged that we are working in area where definitions are evolving, and inevitably the same terms have different nuances for different communities. Certainly within the SCHEMAS project we have been examining our use of te
7、rms such as schema, vocabulary, and namespace and have found that agreeing definitions is an important step in understanding the somewhat confusing landscape of new and emerging metadata standards. An extended glossary of key concepts is available on the SCHEMAS web site 1.The term schema is used in
8、 subtly different ways by different communities, and needs to be treated with care. Sometimes the term is be used in an abstract way to indicate an element set or a vocabulary of terms. However that can be somewhat confusing as for many people a schema implies something more concrete. We prefer to u
9、se element set to denote a coherent, bounded set of metadata terms; whereas we use schema to refer to a structured expression of an element set in a particular syntax (typically the RDF or XML schema language).Application profiles are a type of metadata schema. They can be defined as schemas that co
10、nsist of data elements drawn from one or more element sets, combined together by implementers, and optimised for a particular local application. The usage of the term application profile to capture the implementers perspective on schemas grew out of UKOLNs work on the DESIRE project 2. However, the
11、requirement to describe application specific characteristics of standards is not new, and is used in a somewhat related way by the Z39.50 community where profiles indicate application specific sub-sets of the full standard. Recently use of the term application profile has grown, as it has proved use
12、ful to typify the way implementers mix and match terms from different element sets. Namespaces, we will try to avoid the use of namespaces in this presentation. In brief a namespace is a construct, typically expressed as a URI, that gives a metadata vocabulary term its unique identity. For more deta
13、ils see the SCHEMAS Glossary!Increase in schema creation activityTEL has undergone a quite rigorous consultation exercise in order to reach agreement on a common metadata element set that can be used as the basis for sharing metadata. In this, TEL is facing the same problem as many other emerging in
14、formation services providing access to distributed, diverse metadata sources, whether within the corporate, education or public sector. Parallels can be seen between development of the TEL application profile and similar activity associated with the development of application profiles for corporate
15、portals, networks of subject gateways (e.g. the Renardus application profile 3) and services from international organisations. In fact, there is a requirement to identify an appropriate element set wherever metadata is needed. Given the rapid development of new services, and the number of projects b
16、eing funded to explore innovative approaches to provision of information, this means there is significant widespread activity involving formulating schemas. And we should note that this is often a time consuming, intensive activity undertaken by specialist information professionals comes at a price. There are obvious opportunities for cost saving and quality control by making this process of schema creation more effici
