Bry, François; Eckert, Michael
Rule-Based Composite Event Queries. The Language XChangeEQ and its Semantics.
RR 2007: First International Conference on Web Reasoning and Rule Systems, 7. - 8. Juni 2007, Innsbruck, Austria.
Reactive Web systems, Web services, and Web-based publish/
subscribe systems communicate events as XML messages, and in
many cases require composite event detection: it is not sufficient to react
to single event messages, but events have to be considered in relation to
other events that are received over time.
Emphasizing language design and formal semantics, we describe the
rule-based query language XChangeEQ for detecting composite events.
XChangeEQ is designed to completely cover and integrate the four complementary
querying dimensions: event data, event composition, temporal
relationships, and event accumulation. Semantics are provided as
model and fixpoint theories; while this is an established approach for rule
languages, it has not been applied for event queries before.