Modifying Rete to reason temporally

Although researchers stress the importance of relative time representations, most expert system shells with temporal reasoning target real-time domains and use absolute time representations. This ontological assumption limits these systems to domains in which temporal events relate to times of occurrence. A temporal production system (TPS) is a traditional production system augmented with temporal knowledge maintenance routines and a temporal knowledge representation. These additions provide the ability to model relationships between events and they allow, but do not require, events to be associated with times of occurrence. The authors describe a TPS and the modifications of the Rete pattern matching algorithm required to incorporate interval-based temporal semantics and temporal knowledge maintenance routines