[foaf-dev] Re: updated FOAF spec

Henry Story henry.story at bblfish.net
Thu May 31 00:30:47 BST 2007

By the way, thanks for the excellent work. It is really helpful to  
have the content negotiation on terms work again, when explaining the  
semantic web to people. The html page looks a lot better too.

An interesting point against vocabularies that don't use the #term  
btw I noticed now is that it does not make it possible for a click on  
a term such as http://xmlns.com/foaf/0.1/knows to redirect to http:// 
xmlns.com/foaf/spec/#term_knows (or am I wrong?).

The SPARQL example idea sounds good.

I was thinking another interesting thing to do would be to work out  
how to do unit testing of vocabularies and conjunction of  
vocabularies with other vocabularies.  Ontologies should perhaps only  
use the owl:import on ontologies they have done a full bunch of unit  
tests with. (So one should probably never import wordnet). Then a  
vocabulary could specify the other ontologies it had been tested  
with. That would help guide one a little.

Tests could include things like: merging those vocabularies won't  
lead to empty classes, no contradictions, ... (what more?).
One could specify that the vocabularies were tested up to depth n...  
or something.


On 29 May 2007, at 04:24, Dan Brickley wrote:

>> btw, one thing that I sometimes find missing when reading a spec  
>> is some guidance as to which other ontologies play nicely with a  
>> given one. Some ontologies are so minimal it feels like there are  
>> a number of missing properties until one realises that one is  
>> meant to use a dc property for example.
> Yes, ... exactly! Sometimes "finding another way to express  
> yourself" may mean using an alternate namespace/vocab instead.  
> There are many areas that straddle vocabs. Topics are currently a  
> good example; SIOC is stabilising and has its own sioc:topic, there  
> is SKOS, and dc:subject ... and discussions in SKOS scene about how  
> to relate between a thing described as a topic (eg. the topic of  
> Paris) and the "thing itself" (ie. the City). Geography is another  
> one.
> On the SemWeb, describing things in detail will very often involve  
> combining namespaces. And there are no solid conventions for doing  
> so. The Dublin Core community calls these combinations "application  
> profiles" btw. I have some draft ideas floating around from those  
> discussions I should dig out and post. One thought I keep coming  
> back to is the use of a SPARQL query directory (even just a wiki)  
> that keeps some common multi-namespace patterns in a form that  
> allows them to be cited, linked, annotated etc. This appeals to me  
> as a technique that might bridge from human-oriented use cases ("I  
> want to find opening hours of shops that sell XYZ in Bristol, and  
> their telephone number", "I want to find people interested in Iraq,  
> who are qualified as a journalist, and have been there", "I want to  
> find free software that can read this file format" ...) ... with  
> machine-oriented formats. In practice I think a SPARQL directory  
> would have *lots* of queries, rather than one per "application  
> profile", since requirements vary slightly all the time, as do the  
> contents of data-sets. My original thinking was that a single or  
> handful of such queries could capture each "combination" of  
> namespaces, but I now think that a little unrealistic.
> What I'd like to do to explore this further, ... is migrate the  
> FOAF wiki to use openID and (semantic)mediawiki, ... restrict edits  
> to people logging in via openID, ... and make a SPARQL query  
> directory prototype on top of that as a light-ish-weight platform.  
> Plausible?

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