Specifying and Monitoring Composite Events for Semantic Web Services

Execution monitoring of complex web service process models is critical for effective management and control of web services based systems. During the composite process model execution or as part of the after-execution analysis complex event patterns (called composite events) consisting of various primitive events need to be detected. In this paper we introduce the concept of primitive semantic events that are used for monitoring of semantic web services, based on OWL-S. Next, we describe mechanisms for specification and detection of composite events. We present a language based on an event algebra combined with semantic event-filtering expressions using description logics atoms enriched with OWL datatypes and SWRL built-ins. Such a language can be used for specification of composite events allowing a detection of complex event patterns in the flow of primitive events. Furthermore, the semantic filtering allows detection of such events that would otherwise be impossible without the use of semantic descriptions. We also discuss detection mechanisms suitable for runtime execution and after-execution analysis.