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Re: When does a document acquire (web) semantics?

From: John Madden <john.madden@duke.edu>
Date: Mon, 1 Feb 2010 16:53:30 -0500
Cc: Oliver Ruebenacker <curoli@gmail.com>
Message-Id: <2E61A72C-23C5-4410-A3F5-54CE3E4BA511@duke.edu>
To: w3c semweb HCLS <public-semweb-lifesci@w3.org>
Hi Oliver,

I don't want to speak for Eric, and I'm not even sure I've accurately represented his point here. Nor am I sure that they *are* different scenarios.

Instead of saying they are or aren't, let me throw out a scenario that concerns me, and in the context of which they *might* be different, and ask for people to comment.

Suppose I publish a medical document in English, and purport to attach to it an "official" RDF/OWL graph. 

	A problem (sidebar):

	Is this possiible? If so, what makes it "official"? Not sure. Maybe the graph is connected to the document 
	with grddl transform that I have published, which makes explicit the rules I use to go from English to RDF. 
	Maybe the graph contains some assertions that reference some provenance/trust vocabulary, such that 
	triples are contained in it that assert -- in some way -- that it is a privileged graph. Maybe the RDF/XML 
	document has an XMLSig on it and I've stated to the world that I nobody is allowed, under penalty of my 
	wrath, to represent this document by RDF/OWL graphs except provided that ones I've signed are provably 
	consistent with them (which is an inane thing for me to do, and not only because I don't know anybody who 
	is afraid of my wrath.)

	(For a medical document, it might not be *me* that insists on this claim; it might be my employer/hospital. 
	They don't want people attributing meanings to the document other than those they have had a chance 
	to approve, because they don't want somebody claiming the RDF/OWL they published led to a subsequent 
	adverse event (by, e.g. being used in a decision support system at some later time that attributed a different 
	meaning to some vocabulary item). So for example they might only allow locally defined classes properties 
	to be used in the graph.)

Anyway, I somehow put a stake in the ground and loudly assert that **this** is what it means.

Now later Eric comes along and wants access to my document, and many others in a bunch of different databases, because he is aggregating data about patient encounters for a research project of his. In his SPARQL query, he does a bunch of joins, that in effect are mappings between the local vocabularies in the existing RDF graphs and whatever vocabularies he's attempting to aggregate to. In this process, my "official" RDF triples get left behind.

Is this a possible scenario? Where does it fail? Is it that the SemWeb doesn't support any notion of an "official" graph? Is it that there is no such thing as an "official graph" at all (on the sem web or anywhere else)?

John






On Feb 1, 2010, at 3:14 PM, Oliver Ruebenacker wrote:

>     Hello,
> 
> On Mon, Feb 1, 2010 at 1:30 PM, John Madden <john.madden@duke.edu> wrote:
>> We had an interesting call in TERM today. One of the topics I would like to boil down to the question "When does a document acquire its semantics?" or, "when does a document come to mean something?"
>> 
>> I argued the (admittedly intentionally) radical view that documents have no semantics whatsoever until a reader performs an act of interpretation upon the document, which in the Semantic Web world would be the same as attributing an RDF/OWL graph to the document.
>> 
>> Even if the author of the document attributes a a particular RDF/OWL graph to her won document, I argued that this graph is not privileged in any way. That others could justifiably argue that the author's own RDF/OWL graph is incomplete, or flawed, or irrelevant, or even incorrect. And the same is true of any subsequent interpreters (i.e. authors of RDF/OWL graphs that purport to represent the "meaning" of the same document).
>> 
>> Eric argued a really interesting point. He argued (and Eric, correct me if I'm interpreting you wrong here), that semantics instead come into existence (or perhaps *can* come into existence) at the point when somebody executes a SPARQL query on a set of RDF/OWL graphs. That is to say, maybe I'm wrong and semantics doesn't even come into existence when somebody attributes an RDF/XML graph to a document; but rather it only comes into existence when somebody queries across (possibly) many graphs of many different people.
>> 
>> What do you think?
> 
>  Can you give an example were this difference is relevant?
> 
>     Take care
>     Oliver
> 
> -- 
> Oliver Ruebenacker, Computational Cell Biologist
> Systems Biology Linker at Virtual Cell (http://vcell.org/sybil)
> Turning Knowledge Data into Models
> Center for Cell Analysis and Modeling
> http://www.oliver.curiousworld.org
> 
Received on Monday, 1 February 2010 21:54:02 GMT

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