Re: Are you planning to use the Dataset Semantics?

On 9/26/12 1:51 AM, Antoine Zimmermann wrote:
> There are triples stores that do reasoning, and what they contain are 
> datasets. Unfortunately, in this debate, I've not heard from the folks 
> who implement them.
> I'd like to see what, e.g., OWLIM, Virtuoso are doing with named 
> graphs when you switch on inferences, but looking at the 
> documentation, I don't find a clear answer.

We use a pragma in SPARQL. I've published many examples of its use over 
the years [1][2].

Pragma example:
DEFINE input:inference 
"http://dbpedia.org/resource/inference/rules/dbpedia#"

Meaning: conditionally apply this inference context (an ontology URI 
mapped to a rule) as a context lenses to the eventual SPARQL solution. 
Basically, use backward-chained inference to prepare the data to which 
the SPARQL query will apply.

SPARQL Example:

## With Inference Context enabled

DEFINE input:inference 
"http://dbpedia.org/resource/inference/rules/dbpedia#"
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
PREFIX dbpedia-owl: <http://dbpedia.org/ontology/>

SELECT COUNT(*)
FROM <http://dbpedia.org>
WHERE {
?person <http://dbpedia.org/property/dateOfBirth> 
"1967-08-21T00:00:00-04:00"^^xsd:dateTime
}

## Without Inference Context
## DEFINE input:inference 
"http://dbpedia.org/resource/inference/rules/dbpedia#"

PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
PREFIX dbpedia-owl: <http://dbpedia.org/ontology/>

SELECT COUNT(*)
FROM <http://dbpedia.org>
WHERE {
?person <http://dbpedia.org/property/dateOfBirth> 
"1967-08-21T00:00:00-04:00"^^xsd:dateTime
}

Links:

1. http://bit.ly/OEBP7N -- Virtuoso reasoning example using DBpedia instance
2. https://plus.google.com/s/OWL%20Reasoning%20Linked%20Data%20Virtuoso 
-- various G+ posts.

Kingsley
>
> AZ
>
> Le 26/09/2012 00:16, Sandro Hawke a écrit :
>>
>> As we're talking about Dataset Semantics, I'm wondering who will
>> implement reasoners that use them.    I wonder this for two reasons.
>>
>> 1.  We need folks to implement a spec, in order for a spec to become a
>> W3C Recommendation [1].    If it doesn't get implemented, it gets stuck
>> at Candidate Recommendation.   If it's too tied to the other specs, they
>> could all get stuck.  (Fortunately, we can just label the dataset
>> semantics text "at risk" in the spec so we can remove it, if necessary,
>> and let the other specs proceed.)
>>
>> 2.  Some folks might implement it mostly because they like to be feature
>> complete (eg the Jena team, historically) but maybe some other folks
>> will implement it because they want to use it for some application.    I
>> suggest these people should perhaps be given the strongest weight in the
>> Dataset Semantics discussion, if they speak up.    If the proposed
>> semantics solve their problem, they're much more likely to
>> implement-to-spec and be happy.
>>
>> For myself, at this point I'm 70% convinced that I can implement all the
>> dataset use cases I understand (the ones I enumerated in the Federated
>> Phonebook examples, plus SPARQL dump/restore) without any standard
>> dataset semantics beyond having a standard place for metadata (eg the
>> default graph in trig and the service description graph in SPARQL).
>>
>>      -- Sandro
>>
>> [1] http://www.w3.org/2005/10/Process-20051014/tr#cfr
>>
>>
>
>


-- 

Regards,

Kingsley Idehen	
Founder & CEO
OpenLink Software
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