Re: [xdi] Back from ESWC 2011...

[Giovanni Bartolomeo <giovanni.bartolomeo@uniroma2.it>]

Thanks to this very good input from Kaliya I've written the attached  
short paper which has been accepted for poster presentation at ISWC  
2011 (Bonn, Germany, October 23-27, 2011). This time I cc the XRI TC  
since the idea is more about one possible application of XRI cross  
references than about XDI itself :)

Best Regards,
Giovanni

Def. Quota Kaliya <kaliya@mac.com>:

> I just found this surfing around...
> http://www.ibiblio.org/hhalpin/homepage/publications/indefenseofambiguity.html
>
>
> On Jun 11, 2011, at 12:31 PM, Giovanni Bartolomeo wrote:
>
>> Dear colleagues,
>>
>> back from ESWC 2011, here is a brief report of what happened.  
>> Almost all the conference and the annexed summer school was focused  
>> on the success of Linked Open Data (aka the "web of data"): how  
>> much simple is to publish LOD, how many dozens of billions of  
>> triples are in LOD, LOD has finally "killed" ontologies, US and UK  
>> Governments' interests in LOD, etc. etc. To me, this confirms that  
>> we should move on this direction trying to be compatible with the  
>> LOD approach.
>>
>> Introducing my poster, the first issue I faced and clarified was  
>> that the introduction of our "structured" identifiers does not  
>> violate the "URI opaqueness principle" (a longstanding issue  
>> finally solved:). In fact, XRIs are converted into URIs, that the  
>> legacy software can still see as opaque. Nevertheless these URIs  
>> can be still interpreted as identifiers for subjects, predicates  
>> and objects of a given graph (the feature we want to port from XDI  
>> to RDF), by using the traditional RDF reification dictionary, see  
>> below for details on how to.
>>
>> I had the chance to speak with Prof. Chris Bizer, Free University  
>> of Berlin, inventor of DBPedia and one of the founder of the LOD  
>> project. He admitted that our proposed approach is compatible with  
>> the existing LOD infrastructure ("it doesn't break"), but he added  
>> that at the present time they do not have yet figured out  
>> meaningful use cases requiring to address single elements (nodes  
>> and links) inside graphs and statements, as we do in XDI. I  
>> proposed him few possible use cases that our approach could  
>> natively solve (link contracts, versioning, avoiding misuse of  
>> owl:sameAs), etc.
>>
>> Then I discussed with Dr. Denny Vrandecic, Karlsruhe Institute of  
>> Technology (KIT), one of the founder of the semantic media wiki  
>> project; he suggested that the benefits presented in my paper could  
>> have been achieve through a "wise" usage of reification, without  
>> introducing any "structure" inside identifiers. We then elaborated  
>> a bit on this. Actually this is true, but if Danny's approach was  
>> used, then we would need
>>
>> 0- a name for the graph (G)
>> 1- a name for each triple in the graph (T)
>> 2- a statement saying that a given triple T is part of a graph G
>> 3- a name for subject (S), predicate (P) and object (O) of each triple T
>> 4- three statements saying that S, P and O are subject, predicate  
>> and object of the triple T
>>
>> This is computationally expansive when multipled by several  
>> billions of triples in LOD!
>>
>> Another guy from KIT suggested that many RDF triple stores allow to  
>> automatically assign numeric identifiers to triples, subjects,  
>> predicates and objects (_:triple123, _:subject456, _:predicate789,  
>> _:object0123, etc.), without the need of explicitly stating (2) and  
>> (4). However, these numeric identifiers are internal ("local"), and  
>> in general not "understandable" by the rest of the world; on the  
>> contrary the open nature of LOD should drive toward facilities for  
>> "global" access (disambiguating sameness, introducing link  
>> contracts, etc.) and our structured identifiers could fit this goal  
>> better than numeric identifiers.
>>
>> Regarding the demo, it was working also with cross references  
>> (great Mike!); however, people unfamiliar with XDI perceived our  
>> usage of symbols (instead of nouns) as a bit too complex to learn.
>>
>> Take home message: so my final impression was that our proposed  
>> XRI<->URI compatibility mechanism now works fine and seems to have  
>> been understood properly, but we still need to spend time on better  
>> presenting our use cases, if we want a strong point for the  
>> adoption of XRIs and structured identifiers by the semantic  
>> community (in particular by the LOD community). Any volunteer for  
>> this? I'm offering a cohautorship for the next pubblication... :)
>>
>> Best Regards,
>> Giovanni
>>




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iswc11pd_submission_63.pdf