To summarise my last message, might one say "In engineering, configuration
management provides a metaphysics for continuants"?
That is, it defines the process of coming-to-be and ceasing-to-be for
engineering parts and assemblies. (01)
----- Original Message -----
From: "Sean Barker" <sean.barker@xxxxxxxxxxxxx>
To: <ontolog-forum@xxxxxxxxxxxxxxxx>
Sent: Saturday, September 06, 2008 11:44 AM
Subject: Fw: [ontolog-forum] Thing and Class (02)
>
> 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
>>
>
>
> (03)
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