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Schema Design

"RDF schemas" by Thomas Baker (1st workshop)
[HTML] [Powerpoint]
This brief tutorial presents the rationale for RDF, the Resource Description Framework, covering the general data model and focusing on the function, content, and uses of RDF schemas.

"Defining schemas in use" moderator -Makx Dekkers (Breakout session, 1st workshop)
[HTML] [Powerpoint]
In this break-out session in the first SCHEMAS workshop, it was concluded that it is important to work from local requirements and, from that perspective, to try and find common ground enabling interoperability with others. Interoperability is not a goal in itself but needs to be rooted in a business need or political considerations.

"Making sense of schemas" by Thomas Baker (4th Workshop)
[HTML] [Powerpoint]
Metadata is like language -- it is based on vocabularies used in the context of particular schema grammars. Just as dictionaries provide reference tools for natural language, so registries can be used to share information about the semantics of metadata elements. To enable integrated access to Web resources on a grand scale, the W3C Semantic Web activity has defined the Resource Description Framework (RDF) as a common grammar for partially understanding the sheer diversity of metadata languages on the Web.

"User guide on designing interoperable schemas using RDF" by Thomas Baker
[HTML] [PDF] This document provides guidance to implementers on expressing their information models as a series of RDF statements in the style used by the prototype SCHEMAS Registry.

Application Profiles

"What are Application Profiles?" by Rachel Heery (2nd Workshop)
[HTML] [Powerpoint]

"Introduction to Case Study 1: EULER" by Colm Doyle (2nd Workshop)
[HTML]
The EULER project, funded by the European Commission in 1998-2000, aims to integrate some of the most relevant publications-related resources in the field of mathematics. as the basis for the design of the metadata schema, the EULER partners decided to use the Dublin Core Metadata Element Set (DC). However as a service there was also a wish to describe certain aspects of a resource that could not be expressed in Dublin Core. Therefore, the EULER Application Profile uses both DC and EULER specific namespaces, specifies permitted schemes and values for elements and refines to a certain extent standard DC element descriptions.

"Introduction to Case Study 2: DCMI Education" by Prof. Stuart Sutton (2nd Workshop)
[HTML] [Powerpoint]
From 1996, various groups in the field of Educational Technologies have been looking at common sets of metadata elements. The Dublin Core Metadata Element Set was a common basis for many of these initiatives, but because groups were working by themselves, a Tower of Babel resulted with little interoperability beyond basic Dublin Core. With the creation of the Education Working Group an attempt was made to analyse the situation and propose an Education Application Profile with some additions to the Dublin Core Metadata Element Set and Qualifiers.

"Schemas in the real world: application profiles" by Rachel Heery (4th Workshop)
[HTML] [Powerpoint]
The experience of implementation of resource discovery systems shows that customisation and localisation of standard metadata schemas is widespread. Using the concept of 'application profile' we suggest means to express such variants, and propose best practice guidelines.

"SCHEMAS Third Metadata Watch Report" by Makx Dekkers, November 2000
http://www.schemas-forum.org/metadata-watch/third/
The third Metadata Watch Report concentrated on the issue of the development and use of Application Profiles in the various domains covered by the SCHEMAS Metadata Watch. It describes the concept behind Application Profiles, and gives examples of Application Profiles in various areas. A conclusion is that the work on application profiles is in its early stages, that a number of fundamental questions have only begun to be asked and answers need to be found through further research and experimentation. From further work, conclusions can be reached on how application profiles can help implementers to make the best use of experiences from other activities, thereby reducing the resources in the design and implementation phase, as well as helping further harmonisation to take place.

"Interoperability Profiles -- A Strawman Proposal" by Thomas Baker
[HTML] [PDF]
Drawing lessons from the experience of the SCHEMAS Project, this paper proposes, for discussion in wider circles, a model for application profiles designed to facilitate metadata integration in accordance with the Semantic Web philosophy.

"Application profiles: mixing and matching metadata schemas"
Rachel Heery and Manjula Patel, Ariadne No. 25, September 2000 http://www.ariadne.ac.uk/issue25/app-profiles/

"What Terms Does Your Metadata Use? Application Profiles as Machine-Understandable Narratives"
Thomas Baker, Makx Dekkers, Rachel Heery, Manjula Patel and Gauri Salokhe
Journal of Digital information, volume 2, issue 2. http://jodi.ecs.soton.ac.uk/Articles/v02/i02/Baker/
This paper presents a model for declaring, as a series of simple RDF statements, the information model used in an information service and its relation to existing metadata standards.

Registry set-up and maintenance

"Where does the idea of metadata registries come from?"
"Background" by Rachel Heery (1st Workshop)
[HTML] [Powerpoint]

"ISO/IEC 11179" by Manjula Patel (1st Workshop)
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"DESIRE Registry" by Rachel Heery and Manjula Patel (1st Workshop)
[HTML] [Powerpoint]

"Meta-BIB" by Frank Klaproth (1st Workshop)
http://www2.sub.uni-goettingen.de/

"Some applications of metadata registries" by Matthew Dovey (1st Workshop)
[HTML] [Powerpoint]

"Use of registries by a software tool" by Andy Powell (1st Workshop)
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"Publishing and Harvesting RDF schemas" by Thomas Baker (2nd Workshop)
[HTML] [Powerpoint]
To be scalable, metadata registries must be based on schemas harvested directly from information providers over the Web. This presentation shows how the EOR Toolkit "infuses" schemas from multiple sources and integrates them for query and display.

"Managing schemas: The SCHEMAS Forum Registry" by Manjula Patel (3rd Workshop)
[HTML] [Powerpoint]

"Managing schemas: Microsoft Knowledge Network" by Vivian Bliss (3rd Workshop)
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"Managing schemas: EASEL Project" by Neil Evans-Mudie (3rd Workshop)
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"Using the SCHEMAS Forum Registry" by Manjula Patel (4th Workshop)
[HTML] [Powerpoint]
The SCHEMAS Registry contains several metadata element sets as well as a large number of activity reports which describe and comment on various metadata related activities and initiatives

"SCHEMAS Seventh Metadata Watch Report" by Makx Dekkers, December 2001
http://www.schemas-forum.org/metadata-watch/d28/mwr7.htm
The seventh metadata watch report, apart from continuing assessment of ongoing activities in the various domains, has a special focus on Registry activities. As illustrated in the domain reports, many activities are now starting to realise the usefulness of Registries from an understanding that implementations need to interoperate, and that schemas may be shared by applications. Many are still in the phase where a schema is described for humans to read and understand.

"Best practice guidelines for managing a schema registry" by Rachel Heery, February 2002
[HTML] [PDF]
This document suggests some high level guidelines on best practice on managing a registry. It is based on discussion arising from the SCHEMAS workshops and from experience gained in the wider project.

Metadata Activities

The SCHEMAS Metadata Watch brings together information about projects and programmes related to metadata schema design and implementation. This activity has been conducted by the SCHEMAS partners with a network of domain correspondents. Contributors were Thomas Baker, Laurie Causton, Michael Day, Erik Duval, Christian Eilert, Jerme Gastaldi, Annemieke de Jong, Elisabeth Kamphuis, Walter Koch, Roger Longhorn, Derek Kueter, Manjula Patel, Godfrey Rust, Gauri Salokhe and Elise Sfeir.

During the project period, from early 2000 to early 2002, eight reports have been produced, some with a specific focus as follows:

requirements

development and use of Application Profiles

multilingualism and controlled vocabularies

registry implementations

future outlook

From mid-2002, the Metadata Watch reports have been combined with the Standards Framework reports.

Together with the textual reports that can be found at http://www.schemas-forum.org/metadata-watch/, the information contained in the description of the activities has been entered in the SCHEMAS registry at http://www.schemas-forum.org/registry/. The earlier Standards Framework Reports can be found at http://www.schemas-forum.org/stds-framework/

Metadata Watch:Domain reports
The domains that have been covered by the Metadata Watch are the following:

Audiovisual: film industry, broadcast production and archiving, multimedia production

Cultural Heritage: libraries, library services, museums, museum portals, archives

Education: interactive courseware, life-long learning, distance learning, schools, curricula

Government: e-Government initiatives, public sector information

Publishing: book trade and distribution, music/video/multimedia distribution, music recording industry, scientific journals, news agencies, newspapers, copyright management

Other: geospatial information, industry , environmental information

Academic [1] [2] [3]
Audiovisual [1] [2] [3]
Cultural Heritage [3] [5]
Education [1] [2] [3] [5] [6]
Geographical information [1] [2] [3]
Government [6]
Industry [1] [3]
Publishing [1] [2] [3] [5] [6]
Research [1]

Standards

A clickable map showing the relationships between various standards activites.

Registry Activities

GEM, Gateway to Educational Materials
http://www.thegateway.org
GEM provides access to educational materials such as lesson plans and curriculum units and has been a pioneer in the use of metadata standards and vocabulary control.

World Agricultural Center, Food and Agriculture Organization of the United Nations, Rome
http://www.fao.org/waicent/default.htm
"Fighting Hunger with Information", the World Agricultural Center is redesigning its Web strategy with an emphasis on simple metadata (Dublin Core) and vocabulary control (using RDF) of multilingual subject headings for agriculture and related fields."

Multilingual Registry, University of Library and Information Science, Tsukuba, Japan
http://avalon.ulis.ac.jp/registry/
ULIS is developing an RDF-based registry for linking and indexing metadata vocabularies with together with their translations into multiple languages.

Corporation for National Research Initiatives, Reston,
http://www.cnri.reston.va.us
CNRI is building heterogeneity-tolerant middleware for integrating access to a diversity of metadata schemas.

Other relevant materials

how-to RDF

"User guide on designing interoperable schemas using RDF" by Thomas Baker [HTML] [PDF]

"Dave Beckett's Resource Description Framework (RDF) Resource Guide"
Dave Beckett, Ongoing, January 2002
http://www.ilrt.bris.ac.uk/discovery/rdf/resources
This page, maintained by Dave Beckett at ILRT (the Institute for Learning and Research Technology, University of Bristol), brings together a large amount of links to RDF resources including examples, documents, software, tools and projects that use RDF.

"An Introduction to the Resource Description Framework"
Eric Miller, DLib Magazine, May 1998
http://www.dlib.org/dlib/may98/miller/05miller.html
A useful article on the background of RDF by one of its architects, who is currently the leader of the Semantic Web Activity at W3C. RDF is described as an infrastructure that enables the encoding, exchange and reuse of structured metadata, providing a means for publishing both human-readable and machine-processable vocabularies designed to encourage the reuse and extension of metadata semantics among disparate information communities.

"An Idiot's Guide to the Resource Description Framework"
Renato Iannella, January 1999
An Idiot's Guide to the Resource Description Framework
This article gives a basic overview of RDF with short examples of the various constructs. It concludes that the significant benefit that RDF brings is that it will allow the resource description communities to primarily focus on the issues of semantics rather than the syntax and structure of metadata, and allows for the re-use, extendibility and refinement of established resource description standards in machine-readable form.

"Storing RDF in a relational database"
Sergey Melnik, December 2001
http://www-db.stanford.edu/~melnik/rdf/db.html
This Web page summarizes some approaches to storing RDF in a relational database. Its motivation is that using relational database technology to persistently store and manipulate (large amounts of) RDF data gives the advantage that it provides a scalable off-the-shelf solution.

"What is RDF?"
Tim Bray, January 2001
http://www.xml.com/pub/a/2001/01/24/rdf.html
This introductory article works from some simple, real-world examples of the need for metadata. It describes the rules of RDF and gives some characteristics (e.g. independent and distributed, scalable and fit to be exchanged in XML syntax), pointing out that plain XML breaks down on the scalability issue. Bray expresses the opinion that RDF should make the Web more like a library, or a video store, or a phone book, than it is today.

"Putting RDF to Work"
Edd Dumbill, August 2000
http://www.xml.com/pub/a/2000/08/09/rdfdb/
Dumbill points out that the reality of RDF implementation has been frustrating. Many criticise RDF for a complex and confusing syntax, which more often than not obscures the real value. Dumbill describes a approach to use RDFDB, a database tuned for storing and querying descriptions of resources conceived by R.V. Guha, to integrate an environment into which e-mail, web browser, file system, and so on would enter metadata.

Mixing RDF and XML approaches

"XML-Schemas" by Eliot Christian (1st Workshop)
[HTML] [Powerpoint]

"Combining RDF and XML Schemas to Enhance Interoperability Between Metadata Application Profiles"
Jane Hunter and Carl Lagoze
Proceedings WWW10 Conference, May 2001 http://archive.dstc.edu.au/RDU/staff/jane-hunter/www10/paper.html
In this article, Hunter and Lagoze describe a way that RDF Schemas and XML Schemas can be used together. They propose a web metadata architecture which combines the best features of both XML Schema and RDF Schema to enhance metadata interoperability across the web. In their approach, XML Schemas are used for their ability to explicitly define local usage constraints such as content model, occurrence and datatyping constraints. These features make XML Schema language ideal for defining application profiles. RDF Schemas are used to express the semantics of domain-specific metadata models in a machine-understandable syntax which can be used to merge ontologies from multiple domains. Based on their experiences, they suggest that before either schema language moves to the Proposed Recommendation or Recommendation stage, there is a need for a re-examination of the two schema languages and the formulation of mechanisms which cleanly and smoothly integrate their complementary functionality.

"Bridging the Gap between RDF and XML"
Sergey Melnik, December 1999
http://www-db.stanford.edu/~melnik/rdf/fusion.html
Melnik describes a proposal to allow every "legacy" XML document to have an RDF model. He sees as advantages of this approach that semantics of XML documents can be made explicit, allowing both structural and semantic markup to coexist in the same document, and that RDF can be used to annotate existing XML documents.

"The Cambridge Communiqué" W3C, October 1999
http://www.w3.org/TR/1999/NOTE-schema-arch-19991007
In reaction to confusion among implementers about the relationship between the schema work undertaken in the RDF and XML activities, a group consisting of W3C Member representatives and W3C staff involved in the XML and RDF activities met in August 1999 to discuss the architectural relationship between the schema work being undertaken within these two activities. The goals of this meeting were to articulate a vision of this relationship for the Web community, to feed input into the XML Schema Working Group and other W3C activities in support of this vision, and to resolve issues raised in the Member review of the RDF Schema Proposed Recommendation concerning overlap with XML work.

"The ABC Ontology and Model"
Carl Lagoze and Jane Hunter.
Journal of Digital Information 2(2). November 2001.
http://jodi.ecs.soton.ac.uk/Articles/v02/i02/Lagoze/lagoze-final.pdf
This paper describes the latest version of the ABC metadata model, developed within the Harmony international digital library project to provide a common conceptual model to facilitate interoperability between metadata ontologies from different domains.

"Harmonisation of Metadata for Education and Training Communities: Ottawa Communiqué"
DCMI, IMS, IEEE LOM, August 2001 http://standards.edna.edu.au/reports/20010906-1c-DCMI-IMS-IEEE_LTSC_LOM_WD6_ Communique.doc
In the year 2000, a Memorandum of Understanding was agreed between the Dublin Core Metadata Initiative (DCMI), the IMS Global Learning Consortium (IMS) and the IEEE Learning Technology Standards Committee, Learning Object Metadata Working Group (IEEE, LTSC LOM WG). A subsequent meeting in Ottawa in August 2001 identified specific work items, including the publication of a set of common principles and practicalities that should be of value to metadata practitioners in these respective communities as well as among metadata practitioners in general. Publication of this work is expected in early 2002.

Multilingual issues

"Multilinguality" by Prof. Shigeo Sugimoto, University of Library and Information Science, Tsukuba, Japan (3rd Workshop)
[HTML] [Powerpoint]
This presentation describes the design of an RDF-based registry for linking and indexing metadata vocabularies with together with their translations into multiple languages. Aspects of the challenge include distributed maintenance, character encodings, and the synchronisation of versions.

"Multilinguality:Multilingual Knowledge Management as a Strategy to Defeat Poverty and Hunger" by Stephen Katz, WAICENT/FAO of the UN, Rome (3rd Workshop)
[HTML] [Powerpoint]
The Food and Agriculture Organisation of the United Nations disseminates information in developing countries in English, French, Spanish, Arabic, and Chinese. With the volume of information spiralling out of control, FAO is streamlining its Web strategy with an emphasis on simple metadata (Dublin Core) and the use of RDF for a clearinghouse of multilingual controlled vocabularies in agriculture and related fields.

"Schemas development in the SALT Project - Ongoing Work" by Prof Gerard Budin, ISLE Project (3rd Workshop)
Schemas for multilingual language resources - a report from HLT projects
[HTML] [Powerpoint]

TMF Part 1: Basic concepts
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TMF Part 2: Representing data categories
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TMF Part 3: Designing (schemas and) filters
[HTML] [Powerpoint]
SALT Project is developing XML- and RDF-based formats for representing terminologies such as thesauri, glossaries, and lexicons. The goal is to capture the full complexity of multilingual domain-specific terminological and lexical resources in both XML and RDF.

"SCHEMAS Fifth Metadata Watch Report"
Makx Dekkers, August 2001
http://www.schemas-forum.org/metadata-watch/fifth/
Two particular aspects receive special attention in the fifth Metadata Watch Report: multilingualism and controlled vocabularies. On the issue of multilinguality, it may be expected that the gradual rise in importance of non-English communities and resources on the Internet will have an effect on many metadata communities, and that at least some of them will start providing information in multiple languages. For the implementer community, the emphasis should be on implementation guidelines and best-practice examples in local languages to explain the proper use of a standard metadata set in a specific cultural and linguistic context. The issue of controlled vocabularies is now becoming an important discussion topic within and between metadata standardisation and implementation activities. When appropriate controlled vocabularies are publicly available and are consistently used in metadata creation, more useful search facilities can be built and long-term interoperability can be ensured.

Semantic Web and Interoperability

"SCHEMAS and the Semantic Web" by Thomas Baker (3rd Workshop)
[HTML] [Powerpoint]
This presentation examines the roles of namespace schemas and application profiles in merging access to metadata vocabularies. This goal follows the vision articulated and pursued by the World Wide Web Consortium for a Semantic Web where data can be merged from multiple sources and reused for new and unenvisioned purposes.

"Interoperability across metadata standards" by Makx Dekkers (4th Workshop) [HTML] [Powerpoint]
This presentation looks at the major issues to be addressed to ensure interoperability in a landscape of many metadata standards in order to realise the vision of the Semantic Web. It is argued that first and foremost we need to develop an understanding among the people who develop these standards, and that on this basis implementation experience can be gained, leading to best practice examples and guidelines.

Maintained by: UK Office for Library and Information Networking (UKOLN)
Last updated: 09 July 2002