- State-change view - an event is a change in the state of something and as such is reported. Its properties: a change must occur, and this change must be reported. Example: An item previously outside the range of RFID reader, is now within the range of this RFID reader.
- Happening view -- an event is anything that happens, or is contemplated as happening (the EPTS glossary definition), in this case, a change must occur, but its reporting to the system is optional, not every event according to this definition is of interest to be reported. Example: A person sending Email
- Detectable-condition view -- an event is a detectable condition that can trigger a notification, in this case a change does not have to occur, but reporting should occur. Example: A GPS devise reporting track location (note -- location may not have changed since last report. since the track driver went for lunch).
This is an interesting observation, some people argue that only the first type is an event, while the other types are not. My view is that all the above are actually events. The question is whether we can come with an inclusive, agreed upon definition of event, maybe the glossary team (co-lead by Roy Schulte) should take this challenge.
More about event types - later.