In discrete-event systems, to save sensor resources, the agent continuously
adjusts sensor activation decisions according to a sensor activation policy
based on the changing observations. However, new challenges arise for sensor
activations in networked discrete-event systems, where observation delays and
control delays exist between the sensor systems and the agent. In this paper, a
new framework for activating sensors in networked discrete-event systems is
established. In this framework, we construct a communication automaton that
explicitly expresses the interaction process between the agent and the sensor
systems over the observation channel and the control channel. Based on the
communication automaton, we can define dynamic observations of a communicated
string. To guarantee that a sensor activation policy is physically
implementable and insensitive to random control delays and observation delays,
we further introduce the definition of delay feasibility. We show that a delay
feasible sensor activation policy can be used to dynamically activate sensors
even if control delays and observation delays exist. A set of algorithms are
developed to minimize sensor activations in a transition-based domain while
ensuring a given specification condition is satisfied. A practical example is
provided to show the application of the developed sensor activation methods.
Finally, we briefly discuss how to extend the proposed framework to a
decentralized sensing architecture