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Re: First crack at profiles in primer

From: Alan Wu <alan.wu@oracle.com>
Date: Mon, 14 Apr 2008 21:29:36 -0400
Message-ID: <48040500.7000507@oracle.com>
To: Ivan Herman <ivan@w3.org>
CC: Bijan Parsia <bparsia@cs.man.ac.uk>, OWL Working Group WG <public-owl-wg@w3.org>

Ivan,

First of all, I must say I appreciate very much Bijan's hard work.
>
> Personally, I consider OWL-R (and at DL Lite, too, actually) as a kind 
> of a minimal set of extra ontology features that I can build on top of 
> RDFS, while keeping it still easy both to comprehend and to implement. 
> Ie, when you say "OWL-R is ideal for enriching RDF data", I think it 
> is not only a true statement but may be _the_ essential feature. 
> Although I would add something like "..  with a set of minimal 
> ontological statements going beyond RDFS."
>
> Also, I also do not understand why the following is true:
>
> "Compared with DL Lite, OWL-R works better when you have already 
> massaged your data into RDF and are working with it as RDF."
>
> (I would not use the word 'massaged' here, b.t.w.) I could very well 
> imagine to (1) have my data in RDF (2) add a minimal set of OWL 
> statements to further characterize my data and... end up in DL Lite. 
> Ie, I do not see that as a differentiating feature from DL Lite. Both 
> are a simple extension that works very well on top of RDF data.
>
> I guess this still reflect a difficulty that I still have in making a 
> clear high level (ie, user level) distinction between the usage of 
> OWL-R and DL Lite. Maybe your remark in OWL-R saying "when the data 
> must be massaged by additional rules" is the strongest distinction 
> here... I am curious to hear Zhe's opinion.
I believe it is definitively one of the distinctions. Apart from that, 
"enriching RDF data" piece makes a lot of sense to me. OWL-R  can indeed 
be viewed as an extension of RDF(S) with a little OWL semantics. If I am 
going to cast a vote on the most distinguishing point for OWL-R, I will 
vote for this "enriching RDF data and extending RDF/RDFS".

Another thing about OWL-R is that there is this set of rules defined. 
The rule set makes it *easier* for implementors to materialize inference 
graphs if they choose to. Queries, including SPARQL, can be executed 
directly against inference graphs. On top of that, it is possible to ask 
queries like "is there a path between these two nodes" or "show me a few 
paths between these two nodes" or "return me nodes that are connected to 
this one by less than 3 hops."

It is true that this is implementation specific. However, the rule set 
in OWL-R  does make certain implementations easier.

Thanks,
Zhe
Received on Tuesday, 15 April 2008 01:31:48 GMT

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