Re: URIs

Hi Xiaoshu--

Xiaoshu Wang wrote:
> Frank,
> 
>> This isn't to deny the usefulness of being able to dereference a
>> URI and get something useful (or to be able to find the RDF or OWL
>> describing a vocabulary when you're trying to process statements
>> employing that vocabulary).  I'm merely pointing out that RDF and
>> OWL were deliberately trying to use URIs as pure names, and leave
>> the interaction with Web retrieval for additional work.  Now all we
>> need to do is do it :-)
> 
> Thanks for the comments.  From what you referenced, it seems clear
> that RDF/OWL deliberately avoided "the processing issue".  But do you
> know if there is any plan to standardize this.

I don't know of a plan in the sense that there is a timeline (or even a
series of steps) worked out already.  I think this is very much in the
realm of a "best practice" that remains to be worked out, using
discussions such as those going on in this thread.  Once it is worked
out, I think that the W3C would be happy to put their stamp of approval
on whatever makes sense.  Note in this context that the members of the
Interest Group are as much "W3C" as anyone (except the staff), so this
isn't a matter of "W3C" being "them" as opposed to "us".  But I think
that the issues you're discussing apply to areas of science and
engineering beyond biology (I know little about biology, more about
engineering and geospatial apps), and beyond science and engineering as
well.  I expect the products of these discussions will help everybody.

> From what I know, the lack of a processing model for XML document has
> already incurred a lot of problems and TAG is trying to do something
> about it.  IMHO, the lack of a processing model will eventually raise
> inconsistency in RDF model as well.  Because in practice, I just
> cannot help of thinking about it, becaues how an RDF will interpret a
> model will determine how I develop and deploy my models.  I guess
> this "lack of specification" is also what propels Alan to start this 
> dicussion thread on the URIs.
> 

Part of this is a matter of separation of concerns.  RDF as currently 
defined doesn't have a processing model because it's a language, and its 
semantics (at least its current ones) are logically specified;  first 
order logic doesn't have a "processing model" in this sense either, and 
for the same reasons.  What we're trying to deal with here are the 
consequences of trying to hook RDF more tightly into the current Web (if 
you will, it's use in a particular processing context).  The snippet 
from the RDF Model Theory I quoted earlier raises the possibility of 
such semantic extensions.  But they needed to be looked at in the 
context of in-depth application requirements, as is going on now.  You 
mentioned in some of your other messages the distinction that the TAG 
has made between "information resources" and others.  If you go to the 
TAG archives, you will see how much discussion took place prior to 
making that distinction, so it's not surprising that there's a lot of 
discussion still taking place revolving around related issues (not just 
on this list either!).

On a related issue, in another one of your postings I think you hit on
an important point:

> Of course, W3C won't mandate what should be a URI.  But I don't think
> there should be a "standard" to say if a URI represents a biological
> entity, it should be a datebase entry or not.  You can achieve this
> through clear description of URI. For instance, if I declar a URI to
> represent a protein "foo". You can say
> 
> http://www.example.com/foo a someontology:Protein . 
> http://www.example.com/foo http://www.example.com/dbentry (some URI
> to access a dabase) .
> 
> This is semantic clear, right?  Why do we need to design a guideline
> to "implicitly" make
> 
> http://www.example.com/foo to refer to represent certain types of
> entity.  I think one of the important key to RDF is its explicitness.
> If you adds a lot of social guidelines to the RDF, the whole point of
> SW will be lost.

A key to dealing with many of these problems is to make as much as
possible explicit in the RDF.  This can be done in a number of ways.
For example, Alan originally suggested:

> Rather, we can use the URI to the database entry to start to build
> concepts by defining properties and using them in OWL class
> definitions in a variety of ways. In foaf and SKOS, for instance,
> there is a property isPrimarySubjectOf. The kind of equivalence we
> can have between http://www.expasy.org/uniprot/P04637 and
> http://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?db=protein&id=NP_000537
> is something like: The same something isPrimarySubjectof
> http://www.expasy.org/uniprot/P04637 and
> http://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?db=protein&id=NP_000537.
>  where "something" is a blank node in RDF.

Both of you seem to be making the point that if there's a "something" 
that has multiple names, make that explicit, and if there's both a 
"something" and a database entry that describes it, make that explicit 
too.  Once such distinctions are explicit, there are all sorts of 
choices about how to deal with the other issues.

Note, though, that this doesn't obviate the need for a "social 
guideline" since the principle reflected in the above paragraph, if 
adopted, would *be* a "social guideline" (or a "best practice", as some 
of these social guidelines are often termed).  But the resulting RDF 
would reflect the common adoption of that social guideline.  RDF doesn't 
generate itself;  it's going to be generated with respect to some 
modeling principles that reflect social agreements on how things ought 
to be modeled, and tied in with other Web-accessible resources.  The 
point is to be as explicit as possible in the RDF (or OWL), even if 
there's a social guideline behind it.

--Frank

Received on Tuesday, 20 June 2006 21:07:45 UTC