  Topological event detection allows for the distributed computation of
homology by focusing on local changes occurring in a network over time. In this
paper, a model for the monitoring of topological events in dynamically changing
regions will be developed. Regions are approximated as the connected components
of the communication graph of a sensor network, reducing homology computation
to graph homology. Betti number differences together with cyclic neighbor-rings
are used to categorize topological event types. The focus lies on the correct
detection of non-incremental (i.e., multiple concurrently occurring) events and
the necessary region update process. Network number differences between a
network's state before and after events are spread from event nodes into
network regions, allowing for the conflict-free updating of regions independent
of the update messages' order of arrival.
