- From: Leo Sauermann <leo.sauermann@dfki.de>
- Date: Fri, 21 Mar 2008 07:04:44 +0100
- To: "Henry S. Thompson" <ht@inf.ed.ac.uk>
- CC: Richard Cyganiak <richard@cyganiak.de>, www-tag@w3.org, W3C SWEO IG <public-sweo-ig@w3.org>
Hi Henry, TAG, (sweo-ig for the records) As we discussed in the Telco, we cannot have a version of this section where everyone is equally happy. I tried to shorten your proposal. From your proposal I use: * title * parts of your text I remixed it resulting in this: It is important to understand that using URIs, it is possible to identify both a thing (which exists outside of the web) and a web document describing the thing. For example the person Alice is described on her homepage. Bob may not like the look of the homepage, but fancy the person Alice. So two URIs are needed, one for Alice, one for the homepage or a RDF document describing Alice. The question is where to draw the line between the case where either is possible and the case where only descriptions are available. According to W3C guidelines ([AWWW], section 2.2.), we have an Web document (there called information resource) if all its essential characteristics can be conveyed in a message. Examples are a Web page, an image or a product catalog. The URI identifies both the entity and indirectly the message that conveys the characteristics. In HTTP, a 200 response code should be sent when a Web document has been accessed, a different setup is needed when publishing URIs that are meant to identify entities. In the next section, solutions are described that allow you to mint URIs for things and also allow clients to get a description of the thing using standard web technologies. thank you for the input! regards Leo It was Henry S. Thompson who said at the right time 20.03.2008 19:46 the following words: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > I've had a quick try at redrafting section 3.1 of https://gnowsis.opendfki.de/repos/gnowsis/papers/2006_11_concepturi/html/cooluris_sweo_note.html#distinguishing > > 3.1 Distinguishing between representations and descriptions > > Above we assumed that there is a distinction between accessing web > documents on the one hand and accessing descriptions of resources on > the other. The question is where to draw the line between the case > where either is possible and the case where _only_ descriptions are > available.. > > According to W3C guidelines ([AWWW], section 2.2.), we have a Web > document which we can access directly (there called information > resource) if all its essential characteristics can be conveyed in a > message. Examples are a Web page, an image or a music recording. The > URI identifies both the entity and indirectly the message that conveys > the characteristics. There are of course also entities whose > characteristics can not be conveyed in a message. For such entities, > _only_ descriptions of the entity are available for retrieval It's > crucial to not be confused by the fact that a Web document may itself > often describes some other entity, which is not itself a Web > document. For example the person Alice (not a Web document) is > described by her homepage (a Web document). Bob may not like the look > of the homepage, but fancy the person Alice. > > Since our advice above is to only use a 200 response code when a Web > document has been accessed, it follows that when designing URIs and > configuring web servers we need to know when we're talking about > identifying Web documents as such and when we're talking about > descriptions of entities, whether they are Web documents or not. > > Our recommendation is to err on the side of caution: Whenever an > object of interest is not clearly and obviously a document (all its > essential characteristics can be conveyed in a message), then it's > better _not_ to respond with a 200 to a request for the URI > identifying it. > > [Hmm, this is probably useless, but maybe it helps a bit] > - -- > Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh > Half-time member of W3C Team > 2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 131 650-4440 > Fax: (44) 131 650-4587, e-mail: ht@inf.ed.ac.uk > URL: http://www.ltg.ed.ac.uk/~ht/ > [mail really from me _always_ has this .sig -- mail without it is forged spam] > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.2.6 (GNU/Linux) > > iD8DBQFH4rELkjnJixAXWBoRAi7eAJ0WAVsSsaMmA1PdTJywRY+xHh3c8QCfSRDg > oF1LyLv8mYlN3VH5wTSkubk= > =ACGc > -----END PGP SIGNATURE----- > > -- ____________________________________________________ DI Leo Sauermann http://www.dfki.de/~sauermann Deutsches Forschungszentrum fuer Kuenstliche Intelligenz DFKI GmbH Trippstadter Strasse 122 P.O. Box 2080 Fon: +49 631 20575-116 D-67663 Kaiserslautern Fax: +49 631 20575-102 Germany Mail: leo.sauermann@dfki.de Geschaeftsfuehrung: Prof.Dr.Dr.h.c.mult. Wolfgang Wahlster (Vorsitzender) Dr. Walter Olthoff Vorsitzender des Aufsichtsrats: Prof. Dr. h.c. Hans A. Aukes Amtsgericht Kaiserslautern, HRB 2313 ____________________________________________________
Received on Friday, 21 March 2008 06:05:51 UTC