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Ontologies are mainly known from the Semantic Web. The Semantic Web uses the Web Ontology Language (OWL), which is based on Description Logic (DL). The primary purpose of DL is the modeling of domains, i.e. the description of concepts, roles and instances, and represents a subset of the First-Order Logic. An essential feature of DL is that it follows the Open-World Assumption (OWA). The OWA is based on the assumption that an observer does not have complete knowledge of the world and therefore there are three logical states: true, false and unknown. This approach makes sense for a flexible and open information pool like the Internet. For industrial applications (e.g. SQL), however, the Close-Word Assumption has proven to be the only viable way to have a complete overview of information for non-chaotic processes. For example, an airline must be able to rely on the fact that a passenger has not checked in if a seat has been assigned to him and this seat is empty. This remains open for reasoning with OWL. The approach commonly used to remedy this situation with downstream so-called "closure axioms" (e.g. "man is not woman") would explode the modeling effort for the exemplary unoccupied seat.

• OntoBroker is completely implemented in Java and therefore has a very high performance.

  This is Further ehanced by the high parallelism in the resolution of the logical pathways. In this way, OntoBroker benefits directly from the presence of many cores for complex reasoning. Furthermore, several OntoBroker instances can optimize performance using different load balancing methods.

   

   

OntoBroker has one of its greatest strengths in connectivity to the outside world. The Java API makes almost all internal structures easily accessible and is well documented.

Furthermore, OntoBroker has both a SOAP and a SPARQL server available.

An extensive library of connectors as well as a hot-plugin interface for external programs complete the API offering.