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Re: [ontolog-forum] objects and processes

To: "Smith, Barry" <phismith@xxxxxxxxxxx>
Cc: "[ontolog-forum]" <ontolog-forum@xxxxxxxxxxxxxxxx>
From: Ed Barkmeyer <edbark@xxxxxxxx>
Date: Mon, 11 Jun 2007 18:46:32 -0400
Message-id: <466DD0C8.70001@xxxxxxxx>
I wrote:    (01)

>> In my philosophy:
>>    An Event occurs, but is usually considered to be evanescent, 
>> although its
>> effects may well not be.  But a Process is almost always temporally 
>> continuant
>> over some period of time, and in particular over the time of a query 
>> over the
>> relevant knowledge base.    (02)

Barry Smith asked:    (03)

> Can you give a few concrete examples of each?    (04)

In describing manufacturing processes, which is among our major research 
interests, a "process" is often a set of man/machine activities that converts 
some "workpieces" or "materials" to a new (value-added) form.    (05)

For example, a cast engine block may be carefully bored for the insertion of 
the cylinders.  The manual part of the process is setting up and locking down 
the engine block in a precise position on the workbed of a "milling machine" 
and starting an automatic program that properly positions the cutting tool and 
slowly drives it down to the proper depth for the first cylinder hole and then 
moves on to the next, and so on.  If the block is "near net shape", the hole 
is already there, but its edges are rough and its bottom is shallow, and the 
whole process takes anywhere from 12 to 40 minutes, depending on the number of 
cylinders and the metal alloy of the block.    (06)

During the process, one may inquire what engine block (serial number) is in 
work, how long it has been in work, what operator is responsible, whether 
there are any active machine warnings, etc.  One can also distinguish "states" 
of the process, e.g. before the cutting has actually started, or when the 
process is "interruptible" because the cutting tool has been extracted from 
one hole and not yet entered the next.  If a machine warning goes active, one 
wants to interrupt the process and either fix the machine problem or move the 
block at the next interruptible state.  So these processes behave a bit like 
"objects" -- they have identity and they have attributes, and some attributes 
change over time.    (07)

Events can also occur during such a process:  the cutting tool can break, the 
machine can suffer a power failure, or a control failure (where the machine 
moved to somewhere other than the directed position), or an "intrusion" can 
occur, where some foreign body enters the work volume of the machine, often 
causing an automatic "safety stop".  The events are instantaneous, even when 
the effects are lasting.  They have a sort of identity, but it is purely 
archival -- there is a record of the event in the machine log or the 
operator's log, but there are no "continuant" aspects of the event per se.    (08)

>>   Further, a static Relationship may be as continuant
>> as the participating object.
> There are occurrent relations (kicks, kisses) and continuant relations 
> (hates, loves).    (09)

OK, we have the vocabulary problem again.  If "relation" means the formal 
logical model of an abstraction of actualities, then yes, relations can model 
occurrent or continuant phenomena.  When I use the term "relationship", I mean 
a model of a (locally) static, continuant phenomenon, as distinct from a model 
of an 'occurrent' phenomenon.  But occurrent phenomena that have "nonzero 
duration" can behave as either occurrent or continuant depending on your 
viewpoint.  And that is why "(locally)", where the "locality" is in time and 
viewpoint.  If you see the process as current and ongoing, it may have 
continuant properties from your perspective.  If you see the process as a 
discrete historical or future/planned "event", it probably doesn't.    (010)

-Ed    (011)

Edward J. Barkmeyer                        Email: edbark@xxxxxxxx
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263                FAX: +1 301-975-4694    (012)

"The opinions expressed above do not reflect consensus of NIST,
  and have not been reviewed by any Government authority."    (013)

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