OSCAF/NEPOMUK Ontologies

The vision of the Social Semantic Desktop defines a user’s personal information environment as a source and end-point of the Semantic Web: Knowledge workers comprehensively express their information and data with respect to their own conceptualizations. Semantic Web languages and protocols are used to formalize these conceptualizations and for coordinating local and global information access. The Resource Description Framework RDF serves as a common data representation format. We identified several additional requirements for high-level knowledge representation on the social semantic desktop. With a particular focus on addressing certain limitations of RDF, we engineered a novel representational language akin to RDF and the Web Ontology Language OWL, plus a number of other high-level ontologies. Together, they provide a means to build the semantic bridges necessary for data exchange and application integration on distributed social semantic desktops. Although initially designed to fulfill requirements for the NEPOMUK project, these ontologies are useful for the semantic web community in general. 

Ontologies

The specifications for the following published NEPOMUK Ontologies are given below. 

• NRL - NRL is NEPOMUK's Representational Language. Designed on top of RDF, it addresses certain limitations on the part of RDF/S. In particular it includes support for Named Graphs, which although being a widely-popular notion, have not been supported by any representational language so far.  It is also based on a view concept for the tailoring of ontologies. This view concept turned out to be of additional value, as it also provides a mechanism to impose different semantics on the same syntactical structure.
  

• NAO - The NEPOMUK Annotation Ontology is an ontology for annotation, providing vocabulary which is commonly required to annotate resources on the semantic desktop. NAO includes graph metadata vocabulary for describing, or annotating, existing named graphs. 

• NIE - The NEPOMUK Information Element set of ontologies provide vocabulary for describing information elements which are commonly present on the semantic desktop. The following documents collectively make up the complete specifications for the Nepomuk Information Element Ontology Framework: 

• NIE (core) - NEPOMUK Information Element Core Ontology

• NFO - NEPOMUK File Ontology

• NCO - NEPOMUK Contact Ontology

• NMO - NEPOMUK Message Ontology

• NCAL - NEPOMUK Calendar Ontology

• NEXIF - NEPOMUK EXIF Ontology
  

• NID3 - NEPOMUK ID3 Ontology
  

• PIMO - Personal Information Model ontology can be used to express Personal Information Models of individuals.

• TMO - Task Model Ontology can be used to describe personal tasks of individuals, as well known as to-do lists.

Contact & Feedback

The ontology maintainers collaborate using a sourceforge project, to contact responsible ontology maintainers, read communication.

Maintenance and download

The NEPOMUK ontologies are maintained by the OSCA-Foundation and contributors from open source projects. This page and the ontologies are kept in a public subversion repository here. You can download it using subversion clients.

Publications & Presentations

• Distributed Knowledge Representation on the Social Semantic Desktop: Named Graphs, Views and Roles in NRL, by Michael Sintek, Ludger van Elst, Simon Scerri and Siegfried Handschuh. European Semantic Web Conference (ESWC07), Innsbruck, Austria. June 2007. [PDF] [Presentation]
• A Protégé Plug-in Development to Support the NEPOMUK Representational Language, by Milena Caires, Simon Scerri, Siegfried Handschuh, Michael Sintek, Ludger van Elst. 10th International Protégé Conference, Budapest, Hungary. July 2007. [PDF] [Presentation]

Applications

NRL Translator

• Online Service [Link]
• A Downloadable Script
• Protégé NRL Exporter Plugin [Link]

Implementations

• The Aperture Toolkit to extract information.
• The NEPOMUK-KDE semantic desktop.