To: | "[ontolog-forum] " <ontolog-forum@xxxxxxxxxxxxxxxx> |
---|---|
From: | "Richard H. McCullough" <rhm@xxxxxxxxxxxxx> |
Date: | Sat, 6 Sep 2008 07:39:39 -0700 |
Message-id: | <805CCC6BB3984D79B1722BF4D5BF9AF7@rhm8200> |
Sean
I have one remaining question -- what does
your
concept hierarchy look like?
In my tabula rasa hierarchy, parts are
characteristics
of the entity
that they are a part of. So you might
have something like this
existent
entity
car
characteristic
part
chassis
engine
proposition
But when the car is disassembled, it would look
like this
existent
entity
chassis
engine
characteristic
part
proposition
Thus my concept hierarchy - my point of view
- changes
with time, as the parts are assembled or
disassembled.
In your case, I would think the designers,
manufacturers,
sales personnel, etc. would have different
hierarchies.
Dick McCullough
Ayn Rand do speak od mKR done; mKE do enhance od Real Intelligence done; knowledge := man do identify od existent done; knowledge haspart proposition list; http://mKRmKE.org/ ----- Original Message -----
From: "Sean Barker" <sean.barker@xxxxxxxxxxxxx>
Sent: Saturday, September 06, 2008 3:44
AM
Subject: [ontolog-forum] Fw: Thing and
Class > Dick, > > In engineering practice (at least as described through ISO > 10303), a part is either an inseparable component or an assembly. An > assembly consists of sub-assemblies (which are assemblies) and > components. The definition of assembly is recursive. > > A product is a part. In ISO 10303, a part is a subtype of a > product, and this is quite distinct from a product concept. Thus, a > product concept might be "Range Rover", a four-wheel drive vehicle, > which is delivered as physically as a part RR1-801/1, or RR1-801/2, or > RR1-803/1, or RR1-805/1, or RR2-810/1, etc, where in RRx-yyy/z, the RRx > is the generic part number, the yyy is the manufacturing assembly suffix > and the /z is the version number. In theory, all parts with the number > RR1-801/1 are completely interchangeable, and should be interchangeable > with parts R1-801/2 (which differs from R1-801/1 in matters not > affecting form, fit or function), however will have some form, fit or > function difference from RR1-803/1. > > The occurrences of the Range Rover concept will also be stamped > with a serial number. A typical maintenance manual will inform you of > changes made in the product standard in terms of the serial numbers that > the change effects - e.g. from 1-100,000 it has a 2.3 litre engine, and > from 100,001 onwards the vehicle has a 2.5 litre engine. In practice, > minor changes which internally generate new part numbers will not be > exposed at the level of the maintence manual. > > Of course, the real situation is rather more complicated, but in > matters of detail, rather than of substance (in the context of this > discussion). > > The point being, that a change approval creates a commitment to > create a new part (car, wheel, bolt, etc) which is either a revision of > an existing part (form, fit, function interchangeable) or a new part. In > the case of an assembly, this may be because it incorporates a new part, > or a new combination of existing parts. Conversely, creating a new > component part has no effect on end product unless it is embodied in the > chain of assemblies which contributes to an actual part (end product), > which in turn requires that a new version of these assemblies is > produced. > > The issue "is a representation of" versus "is-a" versus > "is-an-instance-of" is a question of how we ground these relationships > and how we ground the concept of part. I ground the concept "part" as a > "form, fit, and function equivalence relation", such that two part > designs (which specify the part) are equivalent if the physical part > they specify is form, fit and function interchangeable. This means that > the physical parts are an instance of the class "part", and that a > design is a specification for the part. That is, the meaning of the > concept "part" is grounded in the results of using individual parts. > Consequently, a design office designs many parts, some of which are > instantiated by the manufacturing department as physical parts. In the > design office, parts instantiate the design process outputs, and are > treated as separate individuals, while in the manufacturing world, a > part is a class for producing physical parts. > > I hope this answers the question. > > > Sean Barker > Bristol, UK > > -----Original Message----- > From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx > [mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Richard H. > McCullough > Sent: 05 September 2008 11:24 > To: [ontolog-forum] > Subject: Re: [ontolog-forum] Thing and Class > > Sean & Dan > > It is hard for me to understand what this discussion is about. > When I see things like > part is described by design > and > part is instance of design > I wonder if you are missing the whole concept of > part is part of design > i.e., the part-whole relation. > > In Sean's last email, time dependence is mentioned, and I wonder -- are > you now talking about a part-whole relation which is time-varying? > > Dick McCullough > Ayn Rand do speak od mKR done; > mKE do enhance od Real Intelligence done; knowledge := man do identify > od existent done; knowledge haspart proposition list; http://mKRmKE.org/ > > ----- Original Message ----- > From: "Sean Barker" <sean.barker@xxxxxxxxxxxxx> > To: <ontolog-forum@xxxxxxxxxxxxxxxx> > Sent: Friday, September 05, 2008 12:25 AM > Subject: [ontolog-forum] Fw: Fw: Thing and Class > > >> >> >> Dan, >> >> While I would agree that, say, the CAD model for a part >> describes the shape of a part, the issue is not one of design but of >> configuration management. In particular, the criterion for being a > part >> A123 is that it is fit, form and function identical to the "typical >> part" A123. The design is an "ontological commitment" that some class > of >> thing exists (will exist). To reject this is to reject the concept of >> "is-a" and of labelling things with the concepts they instantiate. >> >> Conversely, penguins do not stop being penguins just because some has >> sequenced their DNA (written down their design). >> >> The fact that engineering systems are concerned with coming-to-be and >> ceasing-to-be suggests that >> engineering ontologies must use a temporal logic. In fact, many >> engineering >> systems >> are based on effectivities and change notices. The first explicitly >> identifies what components >> make up a product at a particular time or at a point in the product > run, >> while th second >> controls when the definitions are changed. >> >> Sean Barker >> BAE SYSTEMS - Advanced Technology CentreBristol, UK >> >> From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx >> [mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Dan > Corwin >> Sent: 01 September 2008 19:46 >> To: [ontolog-forum] >> Subject: Re: [ontolog-forum] Fw: Thing and Class >> >> >> *** WARNING *** >> >> This mail has originated outside your organization, either from an >> external partner or the Global Internet. >> Keep this in mind if you answer this message. >> >> No magic here, just typical abstract and concrete objects. >> >> Sean Barker wrote: >> >>> 2) The product of a design office is designs, instances of the > general >> >>> mathom "design". In the DO, any class/type structure applied to a set >>> of designs is a generalization of the set of design instances - >>> designs are >> > not classes for anything. >> >> A "design" is surely an object in the world of information. >> It describes something, which you portray below as concrete. >> >>> The product of a manufacturing organization is parts, each of >> > which is an instance of a design. >> >> Wrong. Each "part" may be based on the "design", but their >> relation is described/describes, not instance/class. >> >> regards, >> Dan Corwin >> > > > > > _________________________________________________________________ > Message Archives: http://ontolog.cim3.net/forum/ontolog-forum/ > Subscribe/Config: http://ontolog.cim3.net/mailman/listinfo/ontolog-forum/ > Unsubscribe: mailto:ontolog-forum-leave@xxxxxxxxxxxxxxxx > Shared Files: http://ontolog.cim3.net/file/ > Community Wiki: http://ontolog.cim3.net/wiki/ > To Post: mailto:ontolog-forum@xxxxxxxxxxxxxxxx > > > _________________________________________________________________ Message Archives: http://ontolog.cim3.net/forum/ontolog-forum/ Subscribe/Config: http://ontolog.cim3.net/mailman/listinfo/ontolog-forum/ Unsubscribe: mailto:ontolog-forum-leave@xxxxxxxxxxxxxxxx Shared Files: http://ontolog.cim3.net/file/ Community Wiki: http://ontolog.cim3.net/wiki/ To Post: mailto:ontolog-forum@xxxxxxxxxxxxxxxx (01) |
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