Mere Moments in Time

Scott Francis
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I think Paul Vincent’s blog on CEP is where it’s at – my favorite place to keep tabs on this interesting space.  It isn’t BPM, but it is related to BPM, and vice versa.  Not only are the markets complementary, sometimes the concepts in one space directly make sense in the other.  A side note: often when having trouble designing a process, I think about the important business (or even system) events that might occur – I may not know the actions that happen inbetween, but the events become useful markers around which to design a process. A recent post from Paul caught my attention: “Do Events Have Duration“.
This might seem an odd question, but there are 2 schools of thought here:
  • An event is a point in time.
  • An event is an activity that can take a period of time.
Taking the latter view, we can say things like: Earthquake MMM took place from date-time D1 to date-time D2 Fraudulant act on account NNN took place from date-time D3 to date-time D4 Flight QQ123 was delayed in the period date-time D3 to date-time D4, when it completed disembarkation time T1 late World War 2, an historical event, took place from 1 September 1939 to 2 September 1945.
Lest this make your head hurt, Paul makes a compelling argument that events should be considered moments in time, and an “event” like World War II is really more of a “state” of being in World War II with a start and an end and many other events in between. I think the principle of Occam’s razor applies here: the simplest explanation is usually best. Another side note: my favorite comment on his blog post is one that almost sounds like a snippet from a Star Trek script: “…’temporal semantics of event processing’. In short — events always have durations, but in many cases, the time granularity that we are interested in a certain application is large enough so that we can approximate the duration to a time point (note that a ‘second’ is also an interval and not a point, since time is not discrete).”  I was waiting for something about reconfiguring the deflector shield…

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