RE: XG W3pm Scope

Dear Michel,

I agree that simplicity is a key objective, and see the Dublin Core as a
paradigm for this.

However, complexity often arises from getting the initial design wrong and
then trying to fudge things in afterwards. This is why Matthew said that we
have to be aware that things change with time right from the beginning.

Probably the best approach is - first to do the analysis as correctly as
possible, and then decide what to leave out (or how to simplify) in order to
achieve computability goals.

On the question of quantities and units, we need to put into our ontology
the key concepts defined in standards, such as "quantity", "quantities of
the same kind" and "unit". Whether all these concepts are needed to record
engineering data is another matter, but we have not related our work to the
standards if they are missing.

Best regards,
David

p.s. One of the good things about web work (unlike some standards work) is
that there are continual reality checks in terms of implementation.  This is
why I gave the example of the waterline length of MyShip as:

 <Ship rdf:about="#MyShip">
  <waterlineLength>
   <Length>
    <metre>10</metre>
   </Length>
  </waterlineLength> 
 </Ship>

or equivalently:

 :MyShip :waterlineLength [ :metre 10 ] .

To me it seems simple enough (and is more or less what is in ISO 15926-2).
Evan says that there are problems with this, and it will be good to work on
it under the appropriate topic.

At 23:45 30/05/2008 +0200, you wrote:
>
>wrt:
>"If a primary reason was to support
>reasoning with Description Logic tools, that
>effects what and how you define things in your models.  If you don't
>care about that, you will have more
>freedom."
>
>
>I think not necc. "a primary reason" but certainly it would be quite a
bonus to keep things (if possible) within DL computability....
>
>In general, I hope that we can keep it even more simple than just the
simplicity to keep it in DL. I hoped that we would not just take existing
complex schemas from other initiatives and give them a new syntax only. AS
analogy in models for project mngt.: I prefer Dublin Core above an
owl-version of the OMG PLM Services model of maybe 1000 pages. Well, guess
you see what I mean...
>
>Just to find out the complexities involved: suppose we have a predefined
unit property (not sure how connected to something like an owl:property  or
a ProductProperty class instance etc. but that aside) and the value domain
is an enumeration of existing SI units defined in iso 1000/31...(well, ok,
including exponents for the flexible modelling of algebraic combinations...)
how usefull would this thing already be. Looking at previous communication I
would expect reactions like: "totally useless because...." well and then I
am interested in the arguments to build up complexity in a managed way....
>
>ch/Michel
>
>
>
>
>-----Original Message-----
>From: public-xg-w3pm-request@w3.org on behalf of Evan Wallace
>Sent: Fri 5/30/2008 9:58 PM
>To: Matthew West
>Cc: public-xg-w3pm@w3.org
>Subject: Re: XG W3pm Scope
> 
>
>Matthew West wrote:
>
>> Sorry guys, but I think this is putting the cart before the horse.
>>
>> First I think we need to understand the area we are looking at. It may
well exceed the limitations of any DL.
>>
>> Then we should look at which useful DL subsets there are that can be
exploited by various tools.
>
>I strongly disagree.  First you must know the purpose you have in mind 
>for creating these models in this XG.
>You already had models in EXPRESS to address the sorts of things 
>described by Michel in his scope document. 
>This group was formed because some set of folks wanted to do this in 
>RDFS/OWL.   There can be different
>reasons for wanting to do that.  If a primary reason was to support 
>reasoning with Description Logic tools, that
>effects what and how you define things in your models.  If you don't 
>care about that, you will have more
>freedom.  But you will have made a choice.  Certain design decisions 
>will make DL compatibility quite
>difficult, and some of those choices were already suggested today!  
>(none of this is to say that we don't need
>understand the area we are looking at)
>
>I wasn't saying that you have to go the DL route.  I was merely 
>cautioning that you should understand your
>goals before blindly making decisions that may be implicitly undermining 
>those goals.  It would also be
>helpful to me, as someone who represents the "manufacturing"* community 
>in the OWL WG, to know how
>people from our community want to use the language.  Decisions are made 
>every week in OWL WG changing
>the language design.  I have a perspective on the needs of our domain 
>with respect to OWL, but I am also
>interested in other perspectives from folks motivated enough to work in 
>this XG.
>
>* I am using the term "manufacturing" to broadly refer to design, 
>planning, construction/production, etc. of
>man-made artifacts.  It's the term we tend to use in the Manufacturing 
>Engineering Laboratory :-D .
>
>-Evan
>
>Evan K. Wallace
>Manufacturing Systems Integration Division
>NIST

============================================================
David Leal
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Received on Friday, 30 May 2008 23:44:19 UTC