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Re: OWL and LOD

From: Steve Harris <steve.harris@garlik.com>
Date: Tue, 12 May 2009 11:37:01 +0100
Cc: <public-lod@w3.org>, <semantic-web@w3.org>
Message-Id: <2E673A97-A696-43B5-A024-277473D0C2A6@garlik.com>
To: John Goodwin <john.goodwin@ordnancesurvey.co.uk>
On 12 May 2009, at 11:22, John Goodwin wrote:
>>> I've been integrating various LOD resource for a small demo at work
>>> and have come to the realisation than a bit of relatively
>> simple OWL
>>> goes a long way in making the integration process more
>> complete. Not
>>> that is was a great surprise really, but you soon realise that
>>> owl:sameAs only gets you so far. IMHO we really need to get
>> OWL into
>>> the LOD mix for linking vocabularies/ontologies as well as
>> data at the
>>> instance level. RDFS is not enough.
>>>
>> There are some issues around here, my understanding is that
>> owl:sameAs is used a bit liberally in the LOD world as it is.
>> In principle it seems like a good idea though.
>
> Owl:sameAs is used very liberally - maybe used of owl:disjoint will  
> spot
> a few errors. But could it be that owl:sameAs is used liberally  
> because
> the classes are not fully defined enough to give people enough
> information to make the right links?

I was thinking more of this issue: http://lists.w3.org/Archives/Public/semantic-web/2009May/0071.html
re. slide 26. I've seen this done too, and it's quite concerning.

>>> Other simple examples of needing OWL with LOD are genealogy. I've
>>> started to convert my family tree into RDF, e.g.:
>>>
>>> http://www.johngoodwin.me.uk/family/I0265
>>> http://www.johngoodwin.me.uk/family/I0243
>>>
>>> A bit of OWL e.g.:
>>>
>>> Parent = foaf:Person and isParentOf some foaf:Person
>>>
>>> isParentOf o isBrotherOf -> isUncleOf
>>>
>>> Uncle = foaf:Person and isUncleOf some foaf:Person
>>>
>>> Would save me writing long SPARQL queries for find instances of
>>> Parent, Uncle etc.
>>>
>> Sure, seems like a good idea, that can be better done in the
>> local processor I would have thought though, rather than at
>> the LOD level?
>
> Agreed - at least at first!

I think there's a real question about whether you want data providers  
mandating entailment regimes over their data, with OWL it's probably  
harmless, but when you add RIF rules into the mix it gets a bit more  
complex.

Different apps may want to apply different rules, and there's a risk  
of losing the provenance of entailed triples, if the closure is  
computed at the server side. It's something I addressed in the last  
academic (reasoning) store I built, but I don't think there's any  
consensus on how you handle, or represent that information.

- Steve

-- 
Steve Harris
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Received on Tuesday, 12 May 2009 10:37:43 GMT

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