Composite Event Detection in Active Databases and Distributed Systems

This report summarizes how Snoop, a composite event detection language for active databases, and Sentinel, an implementation of Snoop, were designed and how one can model an ECA-Rule in Snoop. However, it shows also that, by means of the meta-model for event detection algebras, one can recognize that Snoop is not completely coherent and lacks of symmetry as well as of consistency. Moreover, it presents the approach of composite event detection in distributed systems such as in publisher/subscriber architectures as well as in the wide-area event notification service Siena in contrast to event detection in active databases.