Q: If I can say what I like in a FOAF file, even say nothing, and if I can use any semantic web vocabularies at all, all mixed together, how can we ever know if a FOAF file is 'wrong' (broken, in error)?
A: Which answer do you want...? ;)
One part of the answer relates to the detection of inconsistencies in FOAF data.
In particular, checking for documents that contradict themselves is becoming possible, thanks to our use of W3C's Web Ontology language (OWL).
So I wrote a bit about this in the FOAF wiki, see the FoafContradictions article there. I hope to expand on it with more examples and detail about how OWL works, so am writing in wiki rather than weblog mode this time. It should be readable and hopefully useful now.
A natural topic for further attention would be the discovery of disagreements between documents. That's a rich area to explore, as it combines a variety of techniques, eg. logical (people only have one foaf:dateOfBirth) and statistical (20% of FOAF files think my surname is 'Brinkley', maybe they're right...). This is an important topic as it relates to trust strategies, to dealing with stale / dated information, and to the practical problems inherent in any 'semantic web search engine' efforts. But I didn't write about it yet. Take a look at the FoafContradictions piece and let me know if that's a useful level of detail to attempt...
Posted by danbri at July 13, 2003 03:16 AM