- From: Booth, David (HP Software - Boston) <dbooth@hp.com>
- Date: Tue, 22 Jan 2008 20:10:35 +0000
- To: "public-awwsw@w3.org" <public-awwsw@w3.org>
. . . are at
http://www.w3.org/2008/01/22-awwsw-minutes.html
and also below in plain text.
David Booth, Ph.D.
HP Software
+1 617 629 8881 office | dbooth@hp.com
http://www.hp.com/go/software
Opinions expressed herein are those of the author and do not represent the official views of HP unless explicitly stated otherwise.
-----------------------------------
[1]W3C
[1] http://www.w3.org/
- DRAFT -
Architecture of the World Wide Semantic Web (AWWSW)
22 Jan 2008
See also: [2]IRC log
[2] http://www.w3.org/2008/01/22-awwsw-irc
Attendees
Present
Noah, Stuart, Jonathan, DBooth, Alan
Regrets
Chair
Jonathan Rees (jar)
Scribe
dbooth
Contents
* [3]Topics
1. [4]David Booth's email analyzing type contradiction
scenario
* [5]Summary of Action Items
_________________________________________________________
<scribe> Scribe: dbooth
Alan: Sometimes interesting conversations on SemWeb on the ontolog
forum. Some discussions of time now. Also discussed "how do i say
what an resource is?"
<jar> alan asks if others have read the 'clarifying http' paper
David Booth's email analyzing type contradiction scenario
[6]http://lists.w3.org/Archives/Public/public-awwsw/2008Jan/0001.htm
l
[6] http://lists.w3.org/Archives/Public/public-awwsw/2008Jan/0001.html
jar: A couple of things bothered me. NOt sure yet what triple.
Stuart: I also posted a response.
dbooth: Stuart provides a prose rationale for the contradiction; I
provided mechanical.
... Note that this triple is necessary for remembering what URI was
used:
<[7]http://sw-app.org/mic.xhtml#i> log:uri
[7] http://sw-app.org/mic.xhtml#i%3E
"[8]http://sw-app.org/mic.xhtml#i"^^xsd:anyURI .
[8] http://sw-app.org/mic.xhtml#i
<jar> (discussion is about the first rule in dbooth's email.)
<jar> 2nd rule says to assert what we learned by looking at the
response.
<jar> Use of id= in the HTML implies that the #id URI denotes a
portion of a document
<jar> But DocumentPortion is disjoint with foaf:Person. QED
<alanr> that's what owl:imports is for
<alanr> sumo, bfo, dolce
<jar> To get disjointness, probably we should fit our classes into
an upper ontology.
jar: Any pushback on David's analysis?
... Interesting that there is only one mention of resource ?r in
David's analysis.
... Only if you have an explicit resource do you know anything about
what the URI denotes.
Noah: What would you expect to learn?
Stuart: In rule 1 he generates ?rdfa and ?f, you learn about that
resource from asserting ?f.
Alan: Example suggests another warning: You follow the hash rule and
you expect that there will be some statement abot the resource, and
if there isn't there's a surprise.
<jar> it seems to be just a coincidence that you learned about a#b
by getting a rep for a
Noah: That's been one of my puzzlements.
Stuart: I'd prefer that at this stage we restrict our attention to a
monotype -- not RDFa which combines two types.
Noah: So imagine I get a 200 from a resource and you get back
RDF/XML or N3.
... What do we say about what needs to be in that RDF to be
appropriate? If I know I want that URI to be a stock quote, but if
the RDF says it's a picture of a dog, then it seems like something
funny is happening.
<jar> Noah: What should we be able to expect from the RDF that we
get from the resource named by the racine?
Noah: If you take XML, the root of the doc says "here's what i am".
So if the root says "I'm a stock quote" then you're okay, but if it
says "I'm a resume", then it seems bogus.
... One thing about RDF that has puzzled me is that it doesn't come
out and say that.
... RDF tells me extra things taht I didn't ask. Is there a clean
story that everybody understands?
<alanr> no, and there should be
<alanr> but I think you are missing something in saying that the 302
is something separable.
jar: Probably not. I think there's an understanding that the
associated document should tell you info that will be useful to
know.
<alanr> The test of whether you got a stock can't be tested with an
information.
<alanr> You only know that it isn't a stock quote by making an
association between the IR and the thing out in the world
Noah: Let's look at the simple 200 case (not 302 or 303 yet).
<jar> JAR proposes 2nd use case: simple 200 situation (no RDF in the
representations)
<alanr> If you know it is an IR, all you know is that it should
validate as the mime type
Stuart: At one level, an RDF doc is a description. It describes
potentially many things. It may or may not describe itself also. You
could say the same thing in the XMl case.
<alanr> it is information "about" something
Noah: I would claim that a stock quote is info. To assign a URI to
it, and return HTML or text/plain, nobody complains of violating
webarch. I probably cannot return RDF for it. Because if I did that,
I would be saying that the resource is not the stock price, but an
RDF doc with one or more triples in it.
... So I cannot return RDF for an info resource.
Stuart: So what you really has is an HTML doc describing the stock
price.
... You cannot (without much care) con-neg between HTML and RDF. You
have to be very careful to avoid having IDs that are both documents
and people. In Alan's example, there's a line that gives a hint that
the author was confused.
<alanr> this particular case is complicated by the "hash rule". No
hash rule -> no problem of this sort
Noah: So the resource either is the IBM stock price, or it is an RDF
doc that happens to give you the stock price. You wouldn't conneg
between the RDF and the HTML stock price.
Alan: This is a basic problem with info resources. If you get back
an info resource, you realy don't know much about it. Just the mime
type and a bunch of bits. But a stock price is rooted in something
real.
<alanr> "can I convey the stock price to you in bits"?
<jar> noah: not clear where the info that's core to the resource
stops and where the fluff specific to the mime type starts
Noah: First, I think it's very important to get this straight before
we go on to the more complex cases. In the case of an IR, can I
convey the stock price in bits? Yes, so I can give a 200 for it. It
has to be in some MIME type, so it sort of follows that there is
some ambiguity about where the information stops and the fluff that
came with the MIME type started. If we were going to worry about
that, we wouldn't allow conneg.
<jar> dbooth: trying to restate what noah has been saying. not clear
why there's an ambiguity
<jar> noah: 1. stock price only 2. html document saying "the stock
price is..." + the stock price
Noah: if I had two resources w two URIs, one with the name of the
company and price, the other a specific HTML doc with stock price
$25. In the first case it could use conneg.
<alanr> how do I get the stock price in euros? In yen? Also content
negotiation?
Noah: But for the second one, the rep may be identical, but the HTML
is not accidental. It is supposed to be a fixed representation.
... We need to be answer the question: why can there be conneg?
<alanr> content negotiation is a bad idea. I'm on the record saying
this.
<alanr> there's an open tag issue, IIRC saying same
<alanr> I agree with Noah that this question should be asked.
<alanr> what a coincidence, so does the real stock price vary in
time
Stuart: Every w3c doc has a current version URI and a "this" version
URI, and for a while they are the same. So the resource varies over
time. Coherent w how Fielding describes it in REST.
jar: People use the same URI to talk about the time varying behavior
and its currernt rep.
<alanr> only useful if what fielding says about REST is coherent
Stuart: Representations do not have URIs.
jar: That slightly contradicts RFC2616.
Alan: How do I get a resource?
<jar> How can I determined (via audit or any other means) that two
URIs denote the same resource?
Noah: Each time someome requests a resource, you serve a rep.
<alanr> every representation is a resource
Alan: Can I say that every rep is a resource?
Noah: No, my cynical understanding is that every important resource
shoudl have a URI, but reps don't.
Alan: Isn't this saying that anything can be a resource? So how can
we say that reps cannot be reps?
<alanr> a representation can be "served as a resource"
<jar> Can I name a representation with a URI? Consensus: yes. (Noah
is saying this now)
<jar> Is a representation an IR? Tim says no.
<alanr> Does that mean resources are only things that have uris?
Noah: Every time a rep is served, i assign a new URI to that rep. A
get on that URI will tell you what rep was returned at that time.
<jar> A resource is anything that can be named by a URI. (AWWW)
<jar> Time to wind down, everyone
Noah: Stock prices do not in general have URIs by virtue of being
served as reps.
Alan: Two things seem to be going hand in hand that should be
separated: something is a resource then it has a URI?
<alanr> what about bnodes?
Noah: You could say that resources exist, and can have URIs if you
assign them.
<alanr> new class "resources that have URIS". Question is this
equivalentclass "resources"
jar: I'm hearing confusion about resources, web resources, etc. I
suggest some careful email.
... Other suggestions?
<jar> Noah used the term "web resource" ... jar asks what does that
mean?
<alanr> I totally agree!
Noah: I tried to lead us toward a simpler direction first, before we
hit the more complex case.
<alanr> Only jonathan does ;-)
Stuart: I think we should ground out Alan's PDF file example.
<alanr> "promote something to a resource"
+1 to starting simple.
<jar> Use case: One copies a PDF file to a different server. What
are the relationships among the original and copy resources and
representations? Alan will expand this
<scribe> ACTION: Alan to post PDF file use case [recorded in
[9]http://www.w3.org/2008/01/22-awwsw-minutes.html#action01]
<trackbot-ng> Created ACTION-2 - Post PDF file use case [on Alan
Ruttenberg - due 2008-01-29].
<jar> ACTION: jar to reach out to Tim and Pat [recorded in
[10]http://www.w3.org/2008/01/22-awwsw-minutes.html#action02]
<trackbot-ng> Sorry, couldn't find user - jar
<scribe> ACTION: dbooth to write up simple case of serving RDF with
200 response [recorded in
[11]http://www.w3.org/2008/01/22-awwsw-minutes.html#action03]
<trackbot-ng> Created ACTION-3 - Write up simple case of serving RDF
with 200 response [on David Booth - due 2008-01-29].
Summary of Action Items
[NEW] ACTION: Alan to post PDF file use case [recorded in
[12]http://www.w3.org/2008/01/22-awwsw-minutes.html#action01]
[NEW] ACTION: dbooth to write up simple case of serving RDF with 200
response [recorded in
[13]http://www.w3.org/2008/01/22-awwsw-minutes.html#action03]
[NEW] ACTION: jar to reach out to Tim and Pat [recorded in
[14]http://www.w3.org/2008/01/22-awwsw-minutes.html#action02]
[End of minutes]
_________________________________________________________
Minutes formatted by David Booth's [15]scribe.perl version 1.133
([16]CVS log)
$Date: 2008/01/22 15:04:14 $
_________________________________________________________
[15] http://dev.w3.org/cvsweb/~checkout~/2002/scribe/scribedoc.htm
[16] http://dev.w3.org/cvsweb/2002/scribe/
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Guessing input format: RRSAgent_Text_Format (score 1.00)
Found Scribe: dbooth
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Default Present: DBooth, +1.617.452.aaaa, Noah_Mendelsohn, Alan_Ruttenb
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Present: Noah Stuart Jonathan DBooth Alan
Got date from IRC log name: 22 Jan 2008
Guessing minutes URL: [18]http://www.w3.org/2008/01/22-awwsw-minutes.ht
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People with action items: alan dbooth jar
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Received on Tuesday, 22 January 2008 20:11:44 UTC