D6.2.1. Specification of NeOn reference architecture and NeOn APIs

This deliverable describes the NeOn reference architecture, which forms the basis for the software deliverables of the NeOn project. For this architecture important APIs are specified. In the state of the art section we do not aim for a complete description of engineering infrastructures for ontologies. Instead we investigated several technologies, which have the potential to serve as a foundation for the NeOn infrastructure aiming at large-scale, dynamic and networked ontologies. Based on these investigations and on the requirements gathered in the previous deliverable of this NeOn infrastructure work package a reference architecture is developed. In order to serve as the foundation for the software deliverables of the NeOn project emphasis is put on the extensibility and plugability of the infrastructure. Nevertheless it is essential for the usability and scalability goals of NeOn that the architecture has a clear focus in order to allow a good interaction of tools. An example for the realisation of that approach is the adoption of the dual language reasoning by supporting the description language OWL/DL and a rule language. This achieves on the one hand a very good coverage of the almost all ontology language features. On the other hand it has a clear focus on the two most relevant and sufficiently distinct ontology languages instead of trying to have native support for an arbitrary number of ontology languages with minimal differences. For the NeOn reference architecture the important APIs are described. It contains APIs defining lower-level infrastructure functionality. These allow to have different realizations of those components. Additionally it contains APIs which allow to plugin ontology functionality developed in the technical work packages of the NeOn project. Thus a stepwise completion of the NeOn toolkit as the reference implementation for the NeOn architecture is possible. In order to illustrate the architecture finally example components and their assembly to example configurations are given. The example components represents typically category of components as well as typically ontology engineering functionality developed by the technical work packages of the NeOn project.