1. An event processing system, comprising: an event bus configured to receive a stream of events, each said event having a predefined event type; an event processing agent including at least one first processor, the event processing agent being configured to execute predefined queries on the events, each said query conforming to a query language, the query language being enhanced via a semantic extension corresponding to an ontology; and an ontology management component in communication with the event processing agent, the ontology management component including: a first storage location storing mappings between concepts of the query language and concepts of the ontology that enhances the query language, and processing resources, including at least one second processor and a memory, configured to translate references to ontology concepts into translated queries processable by the event processing agent in accordance with the query language, without the semantic extension enhancement.