Re: [regrep-semantic] [UDEF]

["David RR Webber" <david@drrw.info>]

Of course an improved UDEF that is focused on specific
task deliverables - such as identifying alternate or
related spare parts - would not be a bad outcome here.

I think we are all learning - and so having the registry
deliver specific concrete value(s) with UDEF explicitly
is not a bad design goal.

We can worry about a perfect 100% solution once
we've managed to get a useful 20% working first, eh?!

DW.

----- Original Message ----- 
From: <ewallace@cme.nist.gov>
To: <carlmattocks@checkmi.com>
Cc: <regrep-semantic@lists.oasis-open.org>
Sent: Friday, February 06, 2004 5:59 PM
Subject: Re: [regrep-semantic] [UDEF]


>
>
> "Carl Mattocks" <carlmattocks@checkmi.com> wrote:
>
> >This is interesting. I want to now more..
> >
> >Zach:
> >
> >Please expand on the notion of 'UDEF semantic identifiers'.
> >
> >Evan:
> >
> >Please elaborate on 'lattices of these relationships '.
> >
>
> I meant networks rather than strict trees.  A simple example network
> is a class with multiple inheritance.
>
> There are also horizontal relationships like
> synonyms and properties.  Think about a design model of a racecar which
> describes different component systems.  All of these components have
> a partOf relation to the car.  Something like a transmission often
> plays at least two different roles in a hierarchy of component systems
> in a racecar.  It is partOf the drivetrain and may be partOf the load
> bearing structural system.   Twisting all these properties and
> relationships into a strict hierarchy leads to awkward models such as
> the UDEF Object tree.
>
> I didn't mean to imply that supporting lattices was unusual for modeling
> languages.  It isn't.  I was arguing that such expressiveness is necessary
> for useful semantic models.
>
> >Everyone :
> >
> >Please consider if the Semantic Web could leverage "concepts ... denoted
> >by the paths from these nodes to the root rather than the node itself"
>
> To a certain extent they already do.  I was trying to simplify a finer
> distinction.  The path back to the root through subtype relations in an
> RDFS or OWL model of course has implications on a class and instances
> (individuals) of that class.  Just the implications you would expect if
> you have programmed in an Object Orient programming language.  If
> Racecar is a subtypeOf Car is a subtypeOf Vehicle, then any Racecar
> instance is also a Car and a Vehicle instance and inherits the
> characteristics of those supertypes.
>
> By constrast, the relations in the UDEF Object tree do not have any
> explicitly defined implications.  It's only when you have followed the
> path that you might be able to infer what the relations might have been
> along each connection in the path.  This makes the tree hard to navigate
> when looking for a specific concept.  It also can lead to related or
> similar concepts being located quite far apart in the tree.
>
> -Evan
>