Temporal knowledge representation and reasoning model based on Petri nets with time tokens

A new formal model for temporal representation and reasoning is proposed. The model is based on the modification of the Petri nets, called PNTT-Petri Nets with Time Tokens. The PNTT is the main building block of the KRPTT knowledge representation scheme. It integrates the theory of PNTT and Allen´s interval-based temporal logic. The model is suitable for representing activities in temporally rich domains, reasoning as well as planning. The process of reasoning in the scheme is called time dependent event driven reasoning. It includes the ability to reason about the time relationship among actions and/or states, but it also includes the ability to determine the subsequent activities or states based on initial or current activities or states and temporal information associated with each activity or state. An example of the use of the model in temporally rich domain is given.