OMV

OMV - Ontology Metadata Vocabulary

[edit] Motivation

Ontologies have seen quite an enormous development and application in many domains within the last years, especially in the context of the next web generation, the Semantic Web. Besides the work of countless researchers across the world, industry starts developing ontologies to support their daily operative business. Currently, most ontologies exist in pure form without any additional information, e.g. authorship information, such as provided by Dublin Core for text documents. This burden makes it difficult for academia and industry e.g. to identify, find and apply - basically meaning to reuse - ontologies effectively and efficiently. Our contribution consists of a proposal for a metadata standard, so called Ontology Metadata Vocabulary OMV.

[edit] Overview

Ontologies are intended to be used as a shared means of communication between computers and between humans and computers. A core requirement for the achievement of this goal is the usage of open standards and technologies for the representation, description, access and exchange of the ontological sources. Consider, for example, the W3C standardized Web ontology language OWL. Using this representation language instead of a proprietary format would clearly increase the usability of an ontology at Web scale. The same applies for the means employed to describe existing ontologies or for the technological infrastructure supporting their management and exchange.

In contrast to plain Web documents, the majority of implemented ontologies are currently put into widespread use on the Web without any additional metadata information. This deficiency seriously affects the reusability of Semantic Web ontologies: without any metadata information potential ontology users can not find and deploy them effectively and efficiently. In order to cope with this problem, it is necessary to agree on a standard for ontology metadata, a vocabulary of terms and definitions describing ontologies. Replicating the positive experiences in other information management areas e.g. Digital Libraries, implementing such a vocabulary in conjunction with a solid technological infrastructure for creating, maintaining and distributing metadata is expected to increase the real value of ontologies by facilitating their wide scale sharing and reuse.

[edit] Design Principles

[edit] Core and Extensions

Following the usability constraints identifies during the requirements analysis, we decided to design the OMV scheme modularly; OMV distinguishes between the OMV Core and various OMV Extensions. The former captures information which is expected to be relevant to the majority of ontology reuse settings. However, in order to allow ontology developers and users to specify task- or application-specific ontology-related information we foresee the development of OMV extension modules, which are physically separated from the core scheme, while remaining compatible to its elements.

[edit] Ontological Representation

Due to the high accessibility and interoperability requirements, as well as the nature of the metadata, which is intended to describe Semantic Web ontologies, the conceptual model designed in the previous step was implemented in the OWL language. An implementation as XML-Schema or DTD was estimated to restrict the functionality of the ontology management tools using the metadata information (mainly in terms of retrieval capabilities) and to impede metadata exchange at semantical level. Further on, a language such as RDFS does not provide a means to distinguish between required and optional metadata properties. The implementation was performed manually by means of a common ontology editor.

[edit] Identification, Versioning and Location

In OMV we describes a particular representation of an ontology, i.e. an ontology in a particular version at a particular physical location. That means that every different version of an ontology has a different OMV related metadata and consequently, a particular OMV instance is identified by the URI plus the version of the ontology it is describing. In addition to the issue of versioning, an ontology (or a version of an ontology) can be located at different locations. Thus, ontologies with the same logical URI may exist at different physical locations, possibly even with different content. Similar to approach for versioning, we rely on a composite identifier consisting of the logical identifier (URI plus optional version identifier) and a resource locator that specifies the actual physical location.

Of course, the optional version identifier and the optional resource locator can be combined, such that we end up with a tripartite identifier (URI, version, resource locator).

[edit] Metadata Categories

OMV organize the metadata elements according to:

• the type and purpose of the contained information as follows:
  • General
  • Availability
  • Applicability
  • Format
  • Provenance
  • Relationship
  • Statistics
• the impact on the prospected reusability of the described ontological content as follows:
  • Required
  • Optional
  • Extensional

[edit] Development and Sustainability

OMV was designed based on discussions in the EU IST thematic network of excellence Knowledge Web (http://knowledgeweb.semanticweb.org/). The efforts started in mid 2004 by the University of Karlsruhe and Universidad Politecnica de Madrid and the first version of the OMV core was released in May, 2005. During the last years OMV kept evolving (several extensions has been developed and the core has been refined). OMV also has been reused within the NeOn EU Project (http://www.neon-project.org/) as the standard to model the metadata for networked ontologies. Several semantic web applications use or support OMV, such as:

• Oyster
• Onthology.org
• KaonWeb
• Oyster2
• KaonP2P

Many other applications are planning to support OMV in the near future...

[edit] Publications

• Jens Hartmann1, Raul Palma, York Sure, M. Carmen Su´arez-Figueroa, Peter Haase, Asuncion Gomez-Perez, and Rudi Studer. Ontology Metadata Vocabulary and Applications. In Robert Meersman, Zahir Tari, Pilar Herrero et al., International Conference on Ontologies, Databases and Applications of Semantics. In Workshop on Web Semantics (SWWS), pp. 906-915. Springer, October 2005.

• Jens Hartmann, Raul Palma, York Sure, Peter Haase, Mari del Carmen Suárez-Figueroa. OMV -- Ontology Metadata Vocabulary. In Chris Welty, ISWC 2005 - In Ontology Patterns for the Semantic Web. November 2005

• Raul Palma, Jens Hartmann, Asunción Gomez-Perez, York Sure, Peter Haase, Mari Carmen Suarez Figueroa, Rudi Studer. Towards an Ontology Metadata Standard. Poster at 3rd European Semantic Web Conference 2006. ESWC'06. June, 2006. Budva Montenegro

• Jens Hartmann, Elena Paslaru Bontas, Raul Palma, Asuncion Gomez-Perez. DEMO - Design Environment for Metadata Ontologies. 3rd European Semantic Web Conference ESWC06.

[edit] Additional Information

The complete techinical documentation and the OMV ontology(core and extensions) are available for download at http://ontoware.org/projects/omv/ .

If you have questions, please write an email to omv-info@ontoware.org