The key point in the "autonomous" example is that the devices operate
as a swarm rather than as subordinates in a logic hierarchy... so a
"consensus" is required for activation, not just a single reading
that might be erroneous or indicate a localized phenomenon (like a
truck driving past). So how about:
"A set of automatic tsunami sirens have been installed along a
popular Northwest beach. The sirens are controlled by a wireless
network of sensor devices colocated with the sirens. When triggered,
each sensor generates a CAP message containing its location and the
sensed data at that location that is needed for the tsunami
determination. Each siren activates when the combination of its own
readings and those reported at by other devices on the network
indicate an immediate tsunami threat. In addition, a network
component assembles a summary CAP message describing the event and
feeds it to regional and national alerting networks."