-----Original
Message-----
From: David
Price [mailto:david.price@eurostep.com]
Sent: 07 March 2005 14:31
To:
plcs-dex@lists.oasis-open.org
Subject: RE: [plcs-dex]
Classification of type and individual
Please be careful
here. Actual individuals are members of the class defined by their design.
However, actual individuals are not necessarily members of all the classes
of which their design is a member. Classification is not transitive. I
realize that a lot of classification in PLCS replaces subtyping, however
that's not true for all PLCS classifications.
David
-----Original
Message-----
From: Rob
Bodington [mailto:rob.bodington@eurostep.com]
Sent: 07 March 2005 13:38
To: 'Gyllström Leif';
plcs-dex@lists.oasis-open.org
Subject: RE: [plcs-dex]
Classification of type and individual
Thinking about
this a bit more .....
I
think that this approach will get really complicated.
Imagine I have a
bike design classified as an "ordinary" bike.
I
then build an individual bike from this design.
The
individual bike will be classified as an "ordinary"
bike.
I
then make a modification to my individual bike, so it is now a "Souped up
bike".
The
change was not a change to a design, but to my individual bike so "Souped
up bike"
is
not a classification of the design, but a classification of my individual
bike.
So
can we be sure that:
a)
all
classifications of the typical apply equally to the actual thing being
classified.
b)
If we classify a
typical will that classification apply to all of the actual
things
I'm
not convinced (yet)
-----Original
Message-----
From:
Gyllström Leif [mailto:leif.gyllstrom@aerotechtelub.se]
Sent: 07 March 2005 13:11
To:
plcs-dex@lists.oasis-open.org
Subject: SV: [plcs-dex]
Classification of type and individual
I
would suggest that we only classify the typical due to the implications
that the other approach will have on the reference data
library.
We
have agreed that refdata should be regarded as specializations
(subclasses) of PLCS Entities. This would mean that an instance
of
reference data
would have to be defined for both the typical and the actual thing. Yes,
OWL will allow for a class being a subclass of
several Entity
classes. But I'm convinced that this will cause confusion and classes for
typical will only appear as specializations of
the
entity representing the actual etc.
I'm
stongly in favor of keeping the separation of typical and actual,and
exchange both instances, and have a consistent
approach
-----Ursprungligt
meddelande-----
Från:
Rob Bodington [mailto:rob.bodington@eurostep.com]
Skickat: den 18 februari 2005
17:27
Till:
plcs-dex@lists.oasis-open.org
Ämne: [plcs-dex] Classification of
type and individual
Hi
In PLCS we make
a distinction between a typical something and an actual
something.
E.g
Part and
product_as_realized
State_definition
and State_observed
We are also able
to classify things.
E.g.
A Part is
classified as a Bicycle
A
State_definition is classified as a Fault state.
The question is,
if I classify the typical things, do I need to classify the actual
thing?
For example, if
I classify a Part as being a bicycle, do I need to classify the Product
as realised as representing my bike, as a being a bicycle, or do I just
classify the Part?
Similarly for
states.
If we impose a
rule that you only classify the typical - not the actual, then you will
always have to exchange both the typical and the
actual.
Which may be
overkill.
Any
thoughts?
Regards
Rob
-------------------------------------------
Rob
Bodington
Eurostep Limited
Web Page: http://www.eurostep.com
http://www.share-a-space.com
Email:
Rob.Bodington@eurostep.com
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