W3C home > Mailing lists > Public > semantic-web@w3.org > March 2007

Re: Fractal communities: Was: Rich semantics and expressiveness

From: Golda Velez <w3@webglimpse.org>
Date: Wed, 7 Mar 2007 09:37:27 -0700
To: semantic-web@w3.org
Message-Id: <200703070937.28184.w3@webglimpse.org>


Hello Tim, Matthew, Hans & all

I'm a bit out of the mainstream here, but:

- almost everyone has a personal taxonomy that maps onto parts of many 
different ontologies (most folks haven't coded their taxonomies, but they 
exist nontheless).  Presenting these mappings is a useful way for individuals 
to share experience with other humans and provides grist for fuzzy 
classifiers.  I think its still relevent to semantic web because the more 
humans use classifying tools and learn to navigate existing ontologies, that 
is how the (fuzzy) connections are going to get built.

- about the ISBN: stuff.  Of course we should be able to use those 
identifiers, but yes they need a namespace otherwise someone will be 
referring to the "International Society for Butter Nuts".  That can be solved 
if the info: people or someone else offers to provide a stable URL 
referencing them.  Like, info://ns.info/2007/isbn/NNNNNNN
If the namespace owner is trusted and says they will not reinvent the meaning 
of that URL, that's good enough.  It would be nice if w3 or one other central 
org was in the habit of providing such urls.  Note a web page or HTTP 
anything is not necessary if its not a full ontology - its just a URL to ref 
a concept!

keyword is Mapping!

- tools to go back and forth from the RDF world for us old sql programmers.  I 
have a semi-semantic web type app meant for joe user that has 8000+ 
categories and 80000+ items that can all relate to each other, and needs 
flexible and fast ways to display subsets.  So I have it all in mysql.  There 
is a table with a RELATION field with a small set of allowed relations.  It 
seems to me there should eventually be simple tools for porting this kind of 
data into and out of RDF.   Not everyone wants to use RDF as the back end all 
the time..and not all the features of ontologies are needed for all 
applications, but any valid semantic data should be able to be exposed for 
use.

- it seems to me some relations are pretty universal because they are 
abstract.  I'd like to see a lot of reuse in different ontologies of things 
like
	IS_LOCALIZATION_OF
	IS_PERSONALIZATION_OF
	DEPENDS_ON
	CREATED_BY
and so on, these types of words are abstractions humans can relate to totally 
different fields, and could be used pretty universally, no?

Well, as usual I've probably missed the point, but anyway once all the semweb 
stuff is simple enough for me to use then you know you have something 
happening. 

Last point, probably showing my lack of research - so where is the 
registration place with simple categories for all semweb related things?

bye all

--Golda

ps I wrote a more in-depth (even than the above lengthy mail) explanation of 
these kind of points at http://webglimpse.net/Mapping.pdf . mainly its an 
argument for the info: people or someone trusted to make versioned, 
extensible concept urls for standard concept schemes that haven't been 
webified yet.




On Wednesday 07 March 2007 01:20, matthew.west@shell.com wrote:
> <snip>
> > 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.
> 
> MW: One of the counterbalances I find to this is that it is often
> easier/cheaper to reinvent classes than find them (usually lots of 
> versions) and decide if any of them really meet your needs. I know I 
> see a lot of reinvention.
> 
> > - Some ontologies will already exist and by publicly shred by many,  
> > such as ical:dtstart, geo:longitude, etc.  This is the single global  
> > community.
> 
> MW: This is a pure guess, but if we take longitude as an example I
> would be very surprised if there were not at least 100 publicly
> available ontologies that defined longitude. To reduce this, one
> of the things I think we need to do is to develop a sense of
> authoritative source. We need to ask ourselves the question: who
> "owns" this? What is *their* name/definition? This is something we
> try to do with out own reference data. So we recognise ISO country
> codes, rather than invent our own, we recognise a companies product
> name/code when we buy their product, and the companies registered
> name and number, rather than our abbreviation or version of it.
> 
> > - 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.
> 
> MW: This is close to the dynamic view that I see. I see ontologies
> start in isolation and then grow. Eventually, they bump into adjacent
> ontologies that have also been growing (many will die of course).
> 
> MW: When enough ontologies overlap in a sufficiently annoying and
> expensive way, an effort is undertaken to integrate these ontologies
> to better support integration. This produces an increased centre of
> gravity, and almost immediately small ontologies will spring up at 
> the edges, and bigger ontologies will bump into other big ontologies.
> 
> MW: This process repeats, as far as I can see indefinitely. I observe
> that - within Shell at least - the time between integrating at one
> level and integrating at the next level up is about 10 years.
> > 
> > > 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.
> 
> MW: That same kinds of things will happen with the shared ontologies
> as with the enterprise ontologies (moving to a hub and spoke model
> requires an integrating ontology that at least spans the shared data).
> > 
> > 
> > 
> > >
> > > 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.
> 
> MW: Well if this means that we go out to the authoritative source for
> reference data, rather than reinventing it, then that would be 
> consistent with what I was saying above. But at the moment, the problem
> I see is that just about everyone thinks they have the right to be
> an authoritative source on whatever they please. This is not useful.
> 
> > 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,  
> 
> MW: But interestingly, something that was the sum of the authoritative
> sources I have been talking about, would be something like a global
> ontology (but not the only one of course - just a dominant one).
> 
> > 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.
> 
> MW: I'm not convinced about this, though I will concede that 
> authoritative sources might have small or large ontologies with variation
> in the size and spread of their user base. However, I am quite confident
> that we will only get there if we can find a way to reduce the use
> of non-authoritative sources. Of course the web is the only chance we
> have of being able to share these authoritative sources effectively.
> > 
> > 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 Wednesday, 7 March 2007 15:22:08 UTC

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