Re: Fractal communities: Was: Rich semantics and expressiveness

All,

I think one issue that's been missed is that I don't believe the Semantic Web 
is aimed at solving the problem Hans has described. The SW technologies are 
quite useful, but the SW and engineering visions may not be aligned.

Hans, like me, is involved in creating information models, and now ontologies, 
for the engineering disciplines - not for the general public. More precisely, 
these (standard) models are aimed at allowing the integration of information 
across different engineering disciplines, organizations and their supply 
chains and their applications. Engineering applications are typically complex 
and are based on information models/ontologies that have precise 
definitions - i.e. the information models/ontologies themselves are 
engineered. To support the engineering disciplines, evolving, fractal 
ontologies present problems for which there is not currently a solution - or 
at least not a cost effective solution. That's why the top down, upper 
ontology approach can be a solution to "the problem" ... we simply have a 
different problem in the engineering world.

I am, of course, painting a far picture wrt what's in use by engineering 
enterprises today. However, the aims of many are pushing more and more into 
standards of many varieties - even to the point of standardizing the 
applications themselves (e.g. the OMG SysML Systems Modeling Language 
extension to UML).

Cheers,
David

On Saturday 03 March 2007 23:27, Tim Berners-Lee wrote:
> On 2007-03 -03, at 05:19, Hans Teijgeler wrote:
> > Folks,
> >
> > In this context I would like to bring up something that keeps
> > puzzling me.
> >
> > The W3C Semantic Web Activity Statement [1] starts with:
> >
> > "The goal of the Semantic Web initiative is as broad as that of the
> > Web: to create a universal medium for the exchange of data. It is
> > envisaged to smoothly interconnect personal information management,
> > enterprise application integration, and the global sharing of
> > commercial, scientific and cultural data. Facilities to put machine-
> > understandable data on the Web are quickly becoming a high priority
> > for many organizations, individuals and communities."
> >
> > This is great, and it is what we strive for. But it is puzzling how
> > this can ever be achieved without a universal, generic, data-driven
> > model and standard data to drive that model. What I see happening
> > is that everybody can and often does invent instances of owl:Class
> > and owl:ObjectProperty on-the-fly, and then seems to expect that DL
> > will be the band-aid that solves all integration problems. In order
> > to assist the reasoners all sorts of qualifications are added (re
> > OWL1.1), but to me it seems that when this is done, actually a
> > (rather private) data model is created again.
> >
> > Above statement envisages the "smooth interconnection" of a
> > plethora of totally different application domains. That is wise,
> > because we live in one integrated universe (domain), and nobody can
> > dictate where one subdomain stops and the other begins.
>
> Rather than 'domain of discourse' , or set of things considered, I
> think of 'community', set of agents communicating using certain
> terms.  When one thinks in terms of domain of discourse, one tends to
> conclude that everyone who talk at all about a car (say) has cars in
> their domain of discourse and  so everyone must share the model which
> includes the single class Car.
>
> It isn't like that though.  An agent plays a role in many different
> overlapping communities.  When I tag a photo as being of my car, or I
> agree to use my car in a car pool, or when I register the car with
> the Registry of Motor Vehicles, I probably use different
> ontologies.   There is some finite  effort it would take to integrate
> the ontologies, to establish some OWL (or rules, etc) to link them.
>
> - Everyone is encouraged to reuse other people's classes and
> properties to the greatest extent they can.
> - Some ontologies will already exist and by publicly shred by many,
> such as ical:dtstart, geo:longitude, etc.  This is the single global
> community.
> - Some ontologies will be established by smaller communities of many
> sizes.
>
> Why do I think the structure should be will be fractal?  Clearly
> there will be many more small communities, local ontologies, than
> global ones. Why a 1/f distribution? Well, it seems to occur in many
> systems including the web, and may be optimal for some problems.
> That we should design for a fractal distribution of ontologies is a
> hunch.  But it does solve the issue you raise.  Some aspects of the
> web have been shown to be fractal already.
>
> Here are some properties of the interconnections:
>
> - The connections between the ontologies may be made after their
> creation, not necessarily involving the original ontology designers.
> - There is a cost of connecting ontologies, figuring out how they
> connect, which people will pay when and only when they need the
> benefit of extra interoperability.
> - Sometimes when connecting ontologies, it is so awkward there is
> pressure to change the terms that one community uses to fit in better
> with the other community. Again, a finite cost to make the change,
> against a benefit or more interop.
>
> > Hence the need for a universal model as a common denominator. But
> > it is striking that the word "interconnection" was used, rather
> > than "integration". Interconnection reminds me of EAI [2], so hub-
> > based or point-to-point, where Semantic Web integration (as I
> > understand it) involves a web-based distributed data base.
>
> Yes, if web-based means an overlapping set of many ontologies in a
> fractal distribution.
> In his fractal tangle, there wil be several recurring patterns at
> different scales.
> One pattern is a local integration within (say) an enterprise, which
> starts point-point (problems scale as n^2) and then shifts with EIA
> to a hub-and-spoke as you say, where the effort scales as N.    Then
> the hub is converted to use RDF, and that means the hub then plugs
> into a external bus, as it connects to shared ontologies.
>
> > Keeping in mind that, as I wrote before in this thread, application
> > systems store a lot of implicit data (or actually don't store
> > them), the direct mapping of their data to the SW formats will
> > cause more problems than its solves. They are based on their own
> > proprietary data model, and these are unintelligible for other,
> > equally proprietary, data models.
> >
> > The thing puzzling me is how the SW community can see what I cannot
> > see, and that is how on earth you can achieve what your Activity
> > Statement says, without such a standard generic data model and
> > derived standard reference data (taxonomy and ontology). But
> > perhaps not many SW-ers bother about the need of universal
> > integration, and are happily operating within their own subdomain,
> > such as FOAF.
>
> So the idea is that in any one message, some of the terms will be
> from a global ontology, some from subdomains.
> The amount of data which can be reused by another agent will depend
> on how many communities they have in common, how many ontologies they
> share.
>
> In other words, one global ontology is not a solution to the problem,
> and a local subdomain is not a solution either.  But if each agent
> has uses a mix of a few ontologies of different scale, that is forms
> a global solution to the problem.
>
> Tim.
>
> > Can anybody enlighten me, at least by pointing to some useful links?
>
> ummm   http://www.w3.org/DesignIssues/Fractal.html  to which I might
> add this explanation some time.
>
> > Regards,
> > Hans
> >
> > PS The above does not mean that I have no faith in the SW. On the
> > contrary, I preach the SW gospel. But I just want to understand
> > where it is moving to.
> >
> > [1] http://www.w3.org/2001/sw/Activity
> > [2] http://en.wikipedia.org/wiki/Enterprise_Application_Integration
> >
> > ____________________
> > OntoConsult
> > Hans Teijgeler
> > ISO 15926 specialist
> > Netherlands
> > +31-72-509 2005
> > www.InfowebML.ws
> > hans.teijgeler@quicknet.nl
> >
> >
> >
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> > Mar-07 16:19

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Received on Tuesday, 6 March 2007 00:57:57 UTC