ERCIM News No.48, January 2002 [contents]

Third DELOS Workshop on Interoperability and Mediation in Heterogeneous Digital Libraries

by Matthias Hemmje and Umeshwar Dayal

The Third DELOS Workshop on Interoperability and Mediation in Heterogeneous Digital Libraries was held in Darmstadt, Germany, 8-9 September 2001 at Fraunhofer IPSI.

Recent years have seen an explosive growth in the number and diversity of networked digital libraries and information sources. Some of these sources provide general content, others are specific to particular domains. Increasingly, users want to transparently and uniformly access information from these different sources, to integrate information from multiple digital libraries, and to exchange content assembled from different sources.

The workshop was intended to bring together researchers and developers working on digital libraries and related areas for in-depth analysis and discussion of new models, theories, frameworks, and solutions to interoperability in digital libraries.

Interoperability and mediation in distributed, heterogeneous digital libraries require a middleware that provides transparent access to inherently heterogeneous digital collections. Among other things, such a middleware must support data translation between different data types, representations, detection of same-objects, and data propagation for ensuring global consistency. There are research and industrial efforts under way to develop techniques for the modelling, creation, and management of metadata and ontologies for integrating and exchanging content. Transparent search (and metasearch) and consolidation of information from multiple digital libraries pose many challenges beyond the typical problems encountered in web searches and distributed heterogeneous databases. Therefore, this workshop provided a forum for discussing these problems and the approaches that have been taken to address them.

The two-day workshop was organised into four regular paper sessions: ‘Semantics’, ‘Metadata’, ‘Mediation’, ‘Applications’, presenting three to four papers each.

The topics of general interest included several aspects:

  • Design and generation of mediators/wrappers/agents for transparent access to heterogeneous data sources, specific methods supporting various degrees of global consistency
  • Scalable architectures, approaches supporting dynamic registration of heterogeneous collections at mediators/ wrappers/agent levels, query planning, processing, and optimisation in (partially) redundant, heterogeneous data sources
  • Indexing, integration, adaptation, and transformation of heterogeneus datatypes, meta-data generation, registration, reconciliation and exchange
  • Web-based end-user oriented mediation, brokering, as well as sharing of and collaboration within heterogeneous collections.

The workshop brought together researchers and practitioners from fourteen countries. Twenty-seven papers were submitted to the workshop; thirteen were accepted, covering a range of topics from semantics, metadata and mediation to applications. The workshop was also fortunate to include invited talks by Leonid Kalinichenko (‘Subject Information Mediation for Integrated Access to Heterogeneous Collections’) and Steffen Staab (‘Metadata for the Semantic Web’). Furthermore, a plenary discussion on Georeferenced Information was presided over by Michael Freeston.

The organisers are grateful to the DELOS Network of Excellence on Digital Libraries and the National Science Foundation whose support made it possible to organise the workshop as a high quality event.

The proceedings are available on the ERCIM website at

Delos website:

Please contact:
Matthias Hemmje, Fraunhofer IPSI
Tel: +49 6151 869 844