[topicmapmail] what I mean by "context" and "bottom-up"

[Mason, James David (MXM)]

I generally second what Martin has said. 

My experience has been that it's important to decide what sort of thing
you're looking for in any taxonomy. "trademark/model/year/type/engine/"
works if your emphasis is on what options are available at a given time for
a particular model, but it isn't a good model for other things. For example,
Volkswagen makes a 1.8L turbo that they put in half a dozen different models
of Audi and VW products. if you're coming into the subject with an interest
on engines, "trademark/model/year/type/engine/" doesn't work, but Martin's
reversed order does work. 

We've found that hierarchies are useful for some contexts, and that it's
important to keep hierarchies structured by consistent principles (i.e.,
keep "isa" hierarchies separate from "isapartof" hierarchies). Most of our
projects have been in various fields of manufaturing, and we find that we
have to have quite a few hierarchies. Some are common across applications-we
use subsets of materials properties hierarchies in numerous places. We find
component breakdowns to be a common type for manufactured products, but for
those we can't just subset some generic collection the way we can for
properties of alloy steel. But we find that our topic maps link into those
trees in many different ways. We haven't done enough projects yet to have a
good sense of what all the kinds of TM links will be.

Jim Mason
Oak Ridge Y-12 Plant

> -----Original Message-----
> From:	Martin Bryan [SMTP:mtbryan@sgml.u-net.com]
> Sent:	Sunday, October 01, 2000 03:38 a.m.
> To:	Bernard VATANT; topicmapmail@infoloom.com
> Subject:	Re: [topicmapmail] what I mean by "context" and "bottom-up"
> 
> > 1. A community of contributors has to manage a context : define its
> > ontology, scope, subjects, topics, names, associations, types, etc ...
> and
> > build the occurences data base.
> 
> Not necessarily "A community" - its often a set of communities, as the
> current ebXML work for electronic business semantics illustrates clearly.
> 
> > I precise what I mean here by "context " : a field of knowledge, or
> > interest, or activity, or experience (whatever) pragmatically bound by
> the
> > community of people sharing it and speaking a common language, meaning
> by
> > that the semantics are non-ambiguous in the community. 
> 
> I have a different view of context. To me it is the way of identifying
> which subunits of the set of communities that built the onotology use the
> topic for which processes. Most communities use a topic for more than one
> process, but to understand accurately what they mean you have to
> understand what process they are associating the term with at each of its
> occurrences.
> 
> >That's of course an
> > idealistic viewpoint, since in detail, semantics are different for each
> of
> > us, as Jack pointed out. But if you don't split hairs, this definition
> is
> > an operational one. Anyway I insist on this point : a context is
> "embodied"
> > in a community. And it's up to this community to build and clarify its
> > ontology. It's an interesting social work in itself.
> > That's what I meant earlier in my answer to Martin (or maybe Jim ?) to
> be a
> > bottom-up approach :
> > the community and its ontology, whatever its size, is the "local" or
> > "ground" or "bottom" level, and if we have to build more general
> > ontologies, we'll have to merge them somehow. It has nothing to do with
> the
> > way you organize things inside context. Sure if you have to deal with
> car
> > pieces, you've better have some neat hierachy such as
> > trademark/model/year/type/engine/... or the one Martin quoted about air
> > travel reservations ...
> 
> But if you are an engine manufacturer it may be more important to define
> engine/type/model/year/trademark if you want to know that your V16 engine
> was used in the 2000 version of the Ventura that General Motors issued
> under its Vauxhall trademark. (Context is very much dependent on the user
> of the information, not on its creator.)
> 
> > I can't imagine how it could be the other way round : local communities
> > refering to some "general ontology" and trying to adapt it to their
> > context. Which means we may have local top-down approach, inside a local
> > context, but not in a "global context" if that expression makes sense.
> My
> > opinion is that it does not make sense anyway, and the arguments for
> that
> > are both technical and political.
> 
> Note that the context does not necessarily change the underlying ontology,
> but can change the order in which items in the ontology are considered
> relevant.
> 
> > The technical view is that whoever sets the "upper level", they are
> > themselves a community (see SUO), and what they will call "general" is
> only
> > what they suppose at the moment to be general in their implicite
> community
> > ontology, which is *always* cultural-context biased, and will most
> > certainly be irrelevant elsewhere.
> > The political view is that their is no universal concept whatsoever, and
> > trying to setting one is de facto trying to impose its own concept as
> > universal. That's what I call "unique thought". It's an old trap we must
> > always be aware of, because it's very temptative. Maybe I'm myself
> falling
> > in it right now, you'll tell me.
> 
> But for global trading you need a "universally accepted terminology", with
> multiple names but one (translatable) definition.
> 
> Martin
> 
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