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Subject: Re: [plcs-dex] Classification of type and individual


Ah. there is a time-lag om the list. Rob adresses (in other or better) 
words what I brought up in a separate mail.

Regards,
Per-Åke

Rob Bodington wrote:
> I knew that I should have worked harder on the example !!!
> 
>  
> 
> I was trying to make the point that I do not believe that the only way 
> in which an individual can be classified is by classifying the type of 
> which it is an individual.
> 
>  
> 
> I think that there may well be classifications of individuals that are 
> not classifications of the type, and vice versa. Or the type at this 
> instance in time.
> 
>  
> 
> I also think that two individuals of the same type may have different 
> classifications to the classification given to the type. It will be 
> confusing to read a Part21 file if the type is where you go to get the 
> classifications.
> 
>  
> 
> This initially arose from the classification of  State_defnition / State 
> and Condition / Condition_evaluated.
> 
> (type / individual)
> 
>  
> 
> The argument is that in these circumstances you only need to classify 
> the typical, i.e. State_defnition and Condition.
> 
>  
> 
> This is probably true, (well I can’t think of a counter example).
> 
>  
> 
> However, I am not convinced tat it is true  for Part and 
> Product_as_individual.
> 
>  
> 
> Regards
> Rob
> 
> -------------------------------------------   
> Rob Bodington
> Eurostep Limited
> Web Page: http://www.eurostep.com http://www.share-a-space.com
> Email: Rob.Bodington@eurostep.com
> Phone: +44 (0)1454 270030
> Mobile: +44 (0)7796 176 401
> 
> -----Original Message-----
> *From:* Les Debenham [mailto:lad@lsc.co.uk]
> *Sent:* 07 March 2005 14:57
> *To:* plcs-dex@lists.oasis-open.org
> *Subject:* RE: [plcs-dex] Classification of type and individual
> 
>  
> 
> Rob,
> 
>  
> 
> As a support engineer I object to what you did in your third paragraph. 
> Under what circumstances in our work of "Supporting" a product are we 
> going to allow you to modify your bicycle to a non-approved 
> configuration.  At the first configuration audit you will be told to 
> de-modify until your product_as_realized (bike) conforms to its correct 
> configuration. You may apply a change to your configuration if that 
> change (Souped Up) is allowable for your realized instance of the 
> product design (effectivity).
> 
>  
> 
> To be more precise "Souped up" is a variant of the design. You are right 
> it is not a classification.
> 
>  
> 
> Yours configuring for ever,
> 
> Les
> 
>     -----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)
> 
>      
> 
>     Regards
>     Rob
> 
>     -------------------------------------------   
>     Rob Bodington
>     Eurostep Limited
>     Web Page: http://www.eurostep.com http://www.share-a-space.com
>     Email: Rob.Bodington@eurostep.com
>     Phone: +44 (0)1454 270030
>     Mobile: +44 (0)7796 176 401
> 
>     -----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
> 
>      
> 
>     Rob
> 
>      
> 
>     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
> 
>     throughout PLCS.
> 
>      
> 
>     Regards
> 
>      
> 
>     Leif
> 
>         -----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
>         Phone: +44 (0)1454 270030
>         Mobile: +44 (0)7796 176 401
> 
>          
> 
> 
> 
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-- 
========================================================
Per-Åke Ling            email: per-ake.ling_AT_eurostep.com
Eurostep AB             mobile: +46 709 566 490
Vasagatan 38            http://www.eurostep.com
SE-111 20 Stockholm



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