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Re: Review of "Cool URIs for the Semantic Web" - please confirm

From: Leo Sauermann <leo.sauermann@dfki.de>
Date: Wed, 22 Aug 2007 17:28:06 +0200
Message-ID: <46CC5606.9060006@dfki.de>
To: "Williams, Stuart (HP Labs, Bristol)" <skw@hp.com>
CC: www-tag@w3.org, Richard Cyganiak <richard@cyganiak.de>, "'Susie Stephens'" <susie.stephens@gmail.com>, Ivan Herman <ivan@w3.org>

Dear Stuart, members of TAG,

We have changed the "Cool URIs for the Semantic Web" [4] paper according 
to your feedback.

We have made all technical changes requested by the TAG review, fixing 
issues regarding the corret use of 303-redirect.
But we did not switch to "example.com" but still use the example 
"acme.com", based on stilistic reasons.

Before we publish it as W3C Interest Group note within SWEO, could you 
confirm that the reviewed version reflects the view of the TAG and does 
explain the TAG recommendations?

kindest regards
Leo Sauermann

p.s.: below you find the original review done by Stuart Williams, with 
the main issues on top

It was Leo Sauermann who said at the right time 09.08.2007 16:07 the 
following words:
>
> Dear Stuart, members of TAG,
>
> Regarding the "Cool URIs for the Semantic Web" [5] article, which you 
> have reviewed in June 2007.
>
> In the meantime Richard Cyganiak and I have replaced the wrong 
> statements in the article and included nearly all recommendations that 
> you have given us. We also mentioned this review in the 
> Acknowledgements of the paper.
> The revised version is in SVN at [4] and online at [5].
>
> As a next step, we discussed with other SWEO-IG members, amongst them 
> Susie Stephens and Ivan Herman, to publish the article as-is as a SWEO 
> note, contributing to education and outreach. The decision is not yet 
> made, but a logical next step.
>
> The relation to the TAG document [3] remains open, I would assume that 
> the "cool URI" document is an easy-to-read introduction whereas [3] 
> dives deeper. But there is major overlap between the two, so other 
> options may also be possible, if you have an idea how to combine [3] 
> and [4], please contact us.
>
> We chose not to follow one recommendation:
> * "acme.com" was kept instead of "example.com". I contacted the owner 
> of acme.com, but got no feedback. I assume they will not care. The 
> reason to keep it is to keep the "real life" character of the paper, 
> and many readers will be familiar with the imaginary company "ACME.com"
> The paper starts with "if ACME adopts this solution", indicating that 
> we are not affiliated.
>
>
> kindest regards
> Leo Sauermann
>
> [3] http://www.w3.org/2001/tag/doc/httpRange-14/2007-05-31/HttpRange-14
> [4] 
> http://gnowsis.opendfki.de/repos/gnowsis/papers/2006_11_concepturi/html/index.html 
>
> [5] http://www.dfki.uni-kl.de/~sauermann/2006/11/cooluris/
>
> It was Williams, Stuart (HP Labs, Bristol) who said at the right time 
> 18.06.2007 18:08 the following words:
>> Leo et. al.,
>>
>> Firstly, although there are a number of both substantive and editorial
>> comments below on your document [1], it is an excellent document. The
>> clear diagrams and the example section toward the end of the document
>> are particularly useful.
>>
>> I believe that the document is broadly inline with the intention of the
>> TAG's resolution on httpRange-14 [2]. Though the mechanisms described
>> combining content-negotiation and redirection do go beyond the advice
>> given by the TAG resolution.
>>
>> In one place, the document does state:
>>
>>      "For the redirect to the RDF, 302 Found, 303 See other and 
>>     307 Temporary Redirect are all fine;...".
>> This is *not* a statement endorsed by the TAG. The TAG has started to
>> discuss the significance of other redirect codes, but so-far has only
>> advised the use of 303 See other.
>>
>> You may also be aware that the TAG has its own draft finding on this
>> topic [3]. We hope that our work will complement your own in terms of
>> giving clear practical guidance arising from [2].
>>
>> More detailed review comments below.
>>
>>
>> Stuart Williams
>> -- 
>> [1] http://www.dfki.uni-kl.de/~sauermann/2006/11/cooluris/
>> [2] http://lists.w3.org/Archives/Public/www-tag/2005Jun/0039.html
>> [3] http://www.w3.org/2001/tag/doc/httpRange-14/2007-05-31/HttpRange-14
>> -- 
>> Hewlett-Packard Limited registered Office: Cain Road, Bracknell, Berks
>> RG12 1HN Registered No: 690597 England
>> -- 
>>
>> Review of HTML version of     "Cool URIs for the Semantic Web"
>>     http://www.dfki.uni-kl.de/~sauermann/2006/11/cooluris/
>>
>> Stuart Williams for W3C TAG
>> June 2007
>>
>> Agreement
>> =========
>> I think that the TAG would agree with the general advice give in the two
>> boxed statements in the document:
>>
>>     "Be on the web";
>>     "Don't be ambigious"
>>
>> wrt "Be on the web": "Given only a URI, machines and people should be
>> able to retrieve a description about this URI from the web. ..."  This
>> is a little too loose, in that the description is not about the URI but
>> about the resource to which the URI refers. Also, the retrieval result
>> is not always a *description* of the referent. It can be a
>> webarch:Representation of the referent's current state. However, the
>> general priniciple applies, that you would expect to retrieve something
>> of relevance pertaining to the resource by a retrieval operation using
>> its URI.
>>
>> Substantive:
>> ============
>>
>> 2 URIs for Web Documents
>>
>> 4th para last sentence: "... a URL simply identifies whatever we see
>> when we type it into a browser."
>>
>> Sadly not! On a 200 response the URL (Content-location: <URL>)
>> 'identifies' the webarch:Resource that provided the
>> webarch:Representation that is rendered on by the browser. In general,
>> neither the rendering nor the webarch:Representation from which it was
>> rendered have an 'identifying' URL.
>>
>> -- 
>>
>> 2.1 HTTP and Content Negotiation
>>
>> 4th para: "The server could answer... followed by the content of the
>> HTML document in English".
>>
>> It is not clear that the document is intrinically HTML, rather than what
>> is returned is an HTML renderding of the document content in English (as
>> opposed to a PDF rendering of the content in French). I suggest you be
>> more precise that what follows is "...an HTML rendering of the document
>> content in English." or wteo.
>>
>> Could also reference the TAG finding on generic resources:
>> http://www.w3.org/2001/tag/doc/alternatives-discovery.html
>>
>> -- 
>>
>> 3 URIs for Real-World Objects
>>
>> 1st para: "On the semantic web, URIs identify not just web documents,
>> but also..."
>> This statement is true of the traditional web as well. ie. as written,
>> it is presented as being true of just the semantic web.
>>
>> -- 
>>
>> ~8th para: 2nd sentence: "If we can't use document URLs as resource
>> identifiers...".
>> Documents are resources and their URLs are resource identifiers for
>> those documents.
>> -- 
>>
>> 4.1 303 URIs
>>
>> 1st para: "....to distinguish between non-document resources from
>> regular web documents."
>>
>> We sort of trip up on the document word here because there are things
>> which are non-document resources that *are* webarch:InformationResources
>> - eg. a web controlled robot arm is not a document, however it may be
>> controlled through the exchange of webarch:Representations.
>>
>> -- 
>>
>> 4.2 Hash URIs
>>
>> ~6th para: "...(otherwise a client could conclude that the hash URI
>> *represents* a part of the HTML document). Replace "represents" with
>> "refers to".
>>
>> -- 
>>
>> 4.2 Hash URIs
>>
>> ~6th para: "For redirect to RDF,  302 Found, 303 See Other and 307
>> Temporary Redirect are fine..."
>>
>> The TAG does not endorse this statement. The TAG's advice is to to use
>> 303 redirects. It is evident from the record of our meeting in May/June
>> 2007 [a] that we have had some discussion of the significance of other
>> 3xx redirections. However, at present statement above is not a position
>> that the TAG endorses.
>>
>> [a] http://www.w3.org/2001/tag/2007/05/30-minutes#item04
>>
>> -- 
>>
>> 5 Examples from the Web
>>
>> Semantic MediaWiki
>>
>> Whilst one cannot argue with whether or not this is how the Semantic
>> MediaWiki provides URI for its RDF descriptions, URI of the form:
>> http://ontoworld.org/index.php/Special:ExportRDF/Karlsruhe?xmlmime=rdf
>> look terrible - expose underlying techology (PHP); query hack seem to
>> relate to media type... why on earth not something as simple as:
>>
>>     http://ontoworld.org/wiki/<topic> ->
>> http://ontoworld.org/rdf/<topic>
>>
>> or follow the Soton pattern which is really well thought out.
>>
>> Personnally I'd drop the Semantic MediaWiki example from the document
>> until they generate cleaner, less obtuse URI. Particularly in the light
>> of "There are efforts underway..."
>>
>> -- 
>>
>> Editorial:
>> =========
>> 1. Introduction:
>> 2nd para:
>> You state that information has to be expressed as statements about
>> resources and then proceed to give a number of examples all of which are
>> phrased as questions rather than statements. eg. "who are the members of
>> a company". I think these would be better turned around as statements of
>> fact: eg: "Leo Sauerman is affiliated to DFKI".
>>
>> -- 
>>
>> 3rd para: 2nd sentence: "Confusingly, URIs and URLs share the same
>> syntax..." Personnally I don't find that confusing at all - and I am
>> infact more confused by that remark itself. I suggest either dropping
>> the sentence entirely, or simply remarking that URI and URLs share the
>> same generic syntax - that all URLs are URIs but that not all URIs are
>> URLs.
>>
>> -- 
>>
>> 4th para: http://www.acme.com is a real website. Tradition has been to
>> avoid the use of deployed URI/DNS in specs/tutorials and the like -
>> unless they are directly entailed in the spec/tutorial in some way.
>> Typically, although perhaps boringly, URIs based on "example.org" or
>> "example.com" are used. Those DNS names are reserved for the purpose of
>> providing examples - if you pressed I suspect I could find chapter and
>> verse on what they are reserved for. Anyway, you probably shouldn't use
>> acme.com as the domain in your examples.
>>
>> -- 
>>
>> 2: URIs for Web Documents
>>
>> (Picky comment) 3rd para: "Like everything on the traditional web, these
>> are <i>web documents</i>." Follows a pairwise listing of URIs and the
>> things (homepages) they are said to designate (or identify or
>> refer-to...). In the quoted sentence the word "these" needs could bind
>> to either a URI or a homepage or a pair. I suggest you state what it is
>> that are "web documents" more clearly - eg.
>> "Like everything on the traditional web, each of the homepages mentioned
>> above are <i>web documents</i>.
>>
>> -- 
>>
>> I have a mild preference that you avoid the term "Web Document". My main
>> aversion to the word document is it sometime has a webarch:Resource
>> sense and sometimes a webarch:Representation sense - and as a
>> consequence it is not always clear which sense is in use and indeed both
>> may be intended in different parts of the same sentence. OTOH, for an
>> educational document perhaps it is ok to be a little looser - but given
>> the topic area I am not so sure that we can dispense with the precision.
>>
>>
>> Another rational is that the webarch:Representations returned by some
>> webarch:Resources in response to an http GET operation may be
>> programmatically generated - they are more like a UI to a program than
>> something that would be thought of as a document - and that is on the
>> traditional web.
>> Basically, I'm suggesting that you avoid word/terms that could
>> interpreted as referring to either a webarch:Resource or a
>> webarch:Representation. Unfortunately, both "document" and "webpage"
>> suffer this kind of problem.
>>
>> -- 
>>
>> 2.1 HTTP and Content Negotiation
>>
>> 1st para: 1st sentence: Replace "Today's web clients and servers use the
>> HTTP protocol to request web documents..." with "... to request
>> (webarch:)Representations of web documents..."
>>
>> 2nd para: 1st sentence: Replace "When a user agent (e.g. a browser)
>> requests a URL..." with "When a user agent (e.g. a browser) make an HTTP
>> request..." - the browser is not requesting a URL, it has that already.
>>
>> -- 
>>
>> 4.1 303 URIs
>>
>> 1st para: "This practice has been embraced by the W3C Technical
>> Architecture Group in it's <i>httpRange-14 ruling</i>."
>>
>> What was published was as statement that the TAG resolved provide some
>> specific advice to the community. Please refer to this as the TAG's
>> <i>httpRange-14 resolution</i>.
>>
>> -- 
>>
>> 4.2 Hash URIs
>>
>> "data" in http://www.acme.com/data" doesn't really appeal to the
>> intuition that the example URIs give are identifiers for real-world
>> things (a corporation and two particular people) as opposed to data
>> about them.
>>
>> -- 
>>
>> 4.3 Choosing between 303 and Hash
>>
>> "The has URIs have the advantage of reducing the number of necessary
>> HTTP requests." Suggest replacing "HTTP requests" with "HTTP
>> round-trips, which inturn reduces access latency".
>>
>> -- 
>>
>> 6.1 New URI schemes
>>
>> 1st para: "HTTP URIs were originally designed to identify web
>> documents..."
>> Speaking well after the fact about the original intent of the design of
>> some artifact (HTTP URIs) generally creates a hostage to fortune if not
>> substantiated by a contemporary record. The statement may indeed be
>> true, but I would not be so bold as to make it with a means to reference
>> an expression of that original intent.
>>
>>   
>
>


-- 
____________________________________________________
DI Leo Sauermann       http://www.dfki.de/~sauermann 

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Received on Wednesday, 22 August 2007 15:29:20 GMT

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