- From: Miles, AJ \(Alistair\) <A.J.Miles@rl.ac.uk>
- Date: Mon, 10 Oct 2005 15:28:10 +0100
- To: "Thomas Baker" <tbaker@tbaker.de>, "SW Best Practices" <public-swbp-wg@w3.org>
OK by me. > -----Original Message----- > From: public-swbp-wg-request@w3.org > [mailto:public-swbp-wg-request@w3.org]On Behalf Of Thomas Baker > Sent: 10 October 2005 14:55 > To: SW Best Practices > Subject: [VM] Skip Oct 11 telecon? (next Oct 25)? > > > > Dear all, > > The 27 Sep telecon is reported at > http://www.w3.org/2005/09/27-vmtf-minutes.html (and in clear > text below). There were two main actions: > > 1) Danbri to write up how foaf URI dereferencing > works now and how it should be done. > > 2) Tom - same for DCMI. > > I have been liaising with DCMI colleagues on this and have > nothing to report back yet but do expect to have this before > Oct 25. Dan? > > I would prefer to skip tomorrow's scheduled telecon and aim > at the next, on Tuesday, October 25 (1300 UTC/1500 Amsterdam). > > If others have progress to report and would prefer to keep to > the scheduled time, I could arrange to do this though, in that > case, I would prefer to keep the meeting to under 50 minutes. > > What do others prefer? > > Tom > > ---- > > SWBPD VM Task Force > > 27 Sep 2005 Telecon > > Agenda: > http://lists.w3.org/Archives/Public/public-swbp-wg/2005Sep/0111.html > > IRC log: IRC http://www.w3.org/2005/09/27-vmtf-irc > > Previous telecon: 2005-07-19 > http://lists.w3.org/Archives/Public/public-swbp-wg/2005Jul/0064.html > > Attendees > > Chair > Tom Baker > Scribe > Alistair Miles > Present > Dan Brickley > Ralph Swick > Bernard Vatant > > Summary of Action Items > > [NEW] ACTION: danbri to write up how foaf URI dereferencing > works now, and how it should be done. [recorded in > http://www.w3.org/2005/09/27-vmtf-minutes.html#action01] > > [NEW] ACTION: tom to write up current DCMI URI dereferencing > works now, and how it should be done. [recorded in > http://www.w3.org/2005/09/27-vmtf-minutes.html#action02] > > > > In preparation for today's telecon, Alistair described how > SKOS currently > handles dereferencing URIs and proposed some changes to the current > policy. > > RalphS My response to Alistair's thoughts didn't make > complete sense as > I momentarily forgot that SKOS URIs use '#'. > > Tom: Here's the problem: if you click on > http://purl.org/dc/elements/1.1/title in your browser, you get a > screenful of angle brackets -- the top of the RDF schema. So > far, we have > assumed this is reasonable practice, but in Madrid, we agreed > this is no > longer good enough in 2005... The options are: 1) some sort of content > negotiation, or 2) a Web page that somehow points or > redirects to the RDF > schema (e.g. via the link attribute). The idea is that by > default, users > are shown a readable Web page, and applications which want to consume > RDF can do so. In Madrid, no definite conclusion on best way forward. > > Ralph: Important to use solution that respects compatibility with > current tools, which expect to do a GET on property URIs and expect > RDF/XML content. So if we require they do accept > application/rdf+xml it > is probably okay. > > Alistair: What I proposed regarding SKOS Core tries to do > both of these > things: requesting text/html returns a human-readable document. This > is different from what DCMI currently does. If the clients asks for > RDF/XML it gets redirected to something that is RDF/XML. This feature > of DCMI -- using redirects -- is a good idea. So I'm in favor of using > content negotiation. > > Tom: The content negotiation option seems clear; the other option > fuzzy. Was it to have a Web page with an embedded pointer to the RDF > schema, and if enough people did it then applications would have to > handle it? > > Danbri: Remember EricM saying something about linking to RDF. > > RalphS: Published recommendation says something about link. > > Danbri: Webarch provides for content negotiation -- see > http://www.w3.org/TR/webarch/#def-coneg. > > Tom: So do we have a consensus here for content-negotiation? > > RalphS: Other option is embedded RDF (XHMTL 2.0) > > Danbri: Previous FOAF specs have embedded RDF/XML at the expense of > validation. > > Ralph: Support as much RDF as we can as embedded, but not necessarily > everything. RDF/A syntax is what HTML TF is converging on, is it > reasonable to express RDF schema as RDF/A? But RDF/A solution does not > address deployed tools. > > Tom: Does content negotiation raise issues with regard to > deployed tools? > > RalphS: Yes, but cheap and tools should change to do this > anyway. Wanted > to ask if embedded RDF was talked about in Madrid. > > Danbri: I am trying to figure out what do do with FOAF > namespace. Currently, it uses the wrong 30x redirect. > Currently, it goes > from a term URI to the namespace URI -- e.g., Apache "RedirectTemp > /foaf/0.1/Organization http://xmlns.com/foaf/0.1/" goes from > http://xmlns.com/foaf/0.1/Organization to http://xmlns.com/foaf/0.1/. > Can then get that with HTML or RDF. We have discussed doing > redirect so > that e.g. http://xmlsn.com/foaf/0.1/mbox redirects to > spec#term_mbox. But > problem with hash and encoding in Apache with rewriting... Reasonable > for clients to get redirects depending on content type requested. > > RalphS [re Accept: application/rdf+xml] -- it's a shame it > took us several > years to tell application developers what content type to > request, but oh > well. But with the above options, redirects are > content-type-specific? How > do you configure in Apache? > > Danbri Current: RedirectTemp /foaf/0.1/Organization > http://xmlns.com/foaf/0.1/. Possible: RedirectTemp > /foaf/0.1/Organization > http://xmlns.com/foaf/0.1/#term_Organization. Problem 1: # > gets escaped > somehow (reported by Al). Problem 2: This becomes > representation-specific: > #term_Organization is an anchor only in the HTML version of > the namespace > document; it means nothing in the RDF version. > > RalphS It doesn't strike me that different redirects based on Accept: > is architecturally bad, but if there's no apache support > that's an issue > for us. > > Alistair Current browsers preserve their fragID across redirects. > > RalphS So a redirect that includes a fragID would lead to > fragID clashes? > Suspect Alistair is right but wonder if it is actually > endorsed by HTTP > spec. If it is not endorsed then not all browsers may do it. > > Danbri Ah, so a link such as <a > href="http://xmlns.com/foaf/0.1/Organization#term_Organization > ">Organization</a> > might redirect to right part of the HTML document. > > RalphS Perhaps we could ask the TAG if it is legitimate for a > server to > return a fragID in a redirect -- ask the TAG if it is legit > for a server > to return a URI with a hash in a redirect? > > Tom: Stepping back, we seem to have consensus on > content-negotiation on > this call, so we could as a next step write up how this works, leading > to issues with the TAG and compatibility with spec? > > Alistair Apache URI-encodes '#' before serving a redirect to > the client > but purl.org leaves '#' un-encoded. > > Danbrieg <a > href="http://xmlns.com/foaf/0.1/Organization#term_Organization > ">Organization</a> > took me to http://xmlns.com/foaf/0.1/#term_Organization. The option > of "redirect with content negotiation", on a / namespace, means that > term URIs can't redirect to parts of the HTML spec. Am > realising that / > namespace URIs prevent us getting clickable term URIs for > correct sections > of a document. > > I also tested redirects with hash for FOAF -- > http://xmlns.com/foaf/0.1/Organization#xyz . So Apache hash encoding > makes sense if browsers hang on to fragIDs across redirects. > > RalphS: Above redirect is broken. > > Danbri: Can document this as one of the tradeoffs for hash vs slash. > > RalphS: Is there a document which describes FOAF URI resolution policy > now, and what it should be in light of the Madrid discussion? Can > you write this up? Propose you write how it is now, then write best > guess on how it should work -- along the lines of Alistair's SKOS Core > resolution message. > > <danbri> > http://rdfweb.org/viewcvs/viewcvs.cgi/xmlns.com/htdocs/foaf/0. > 1/.htaccess > > <scribe> ACTION: danbri to write up how foaf URI dereferencing > works now, and how it should be done. [recorded in > http://www.w3.org/2005/09/27-vmtf-minutes.html#action01] > > <scribe> ACTION: tom to write up current DCMI URI dereferencing > works now, and how it should be done. [recorded in > http://www.w3.org/2005/09/27-vmtf-minutes.html#action02] > > Alistair We can state our [DCMI, SKOS, FOAF] requirements, > perhaps more > simply than we can describe what currently is implemented. > > Ralph: It's fine to use MUST and SHOULD in a requirements document. > > Tom: MARC Relator codes are currently declared as RDF > properties. Clicking > on a term [ http://www.loc.gov/loc.terms/relators/ILL > currently gets you to a Web page (see also > http://www.loc.gov/loc.terms/relators/dc-relators.html), > but you have to know to go elsewhere for the RDF [ > http://www.loc.gov/loc.terms/relators/dc-relators.xml]. This is nice > for humans, but not ideal for applications. > > Bernard: In recently posting, ask about relationship to Published > Subjects. If we go down this route of making URIs friendly to > both humans > and computers they start to behave alot like publish subjects. Can we > characterise the similarities and differences? When we did Published > Subjects, recommendation for way that computers would use > annexed schemas > was not clear. Published Subjects primarily directed at > humans. Now with > this new state of things we could revisit pubsub. > > RalphS: Useful line of investigation ... gives us way to do > convergence. But one issue is if there is a disagreement between > interpretation of human-readable and machine-readable, which do you > believe? > > Bernard: TMs have no notion of a contradiction, no notion of > consistency, > just some binding points for bits of information about a subject. But > no way to make sure these things are consistent -- which is > why AI folks > don't like TMs. But consistency between human and computer > descriptions > is difficult to control. > > <danbri> "This specification does not attempt to enumerate all the > possible forms of vocabulary description that are useful for > representing > the meaning of RDF classes and properties. Instead, the RDF vocabulary > description strategy is to acknowledge that there are many techniques > through which the meaning of classes and properties can be > described. ..." > > <danbri> rdfs is (on purpose) agnostic re which forms of vocab desc > take precedence > > Tom: Longer-term, DCMI needs to re-examine the policy implications > of declaring vocabularies by expressing the same information both > in a Web document and in an RDF schema -- when does DCMI want to say > which resource is 'authoritative'? Providing parallel representations > implicitly assumes that the representations are in sync. DCMI tries > to ensure this by generating both forms of documentation from a single > source. Currently, the Web pages present somewhat more > information (e.g., > historical versions of term descriptions) than the current RDF schema. > The Web page [ http://dublincore.org/documents/dcmi-terms/] currently > asserts itself to be an "authoritative specification"; the RDF schemas > do not currently make the same assertion. Dublin Core started as an > RFC [http://www.ietf.org/rfc/rfc2413.txt] and as Web documents, and > this precedence of the Web document was never explicitly changed. This > situation could change in the future, especially as DCMI moves towards > saying more about the terms in a formal sense. DCMI would need to be > explicit on authoritative nature of the representations. > > RalphS: Is it a proper subset? Are there e.g. domains and > ranges in RDF > overlooked in HTML? > > Tom: DCMI terms are not currently defined with domains and ranges. A > DCMI working group is currently looking at domains and ranges which > might in principle be assigned to existing DCMI properties in order to > reinforce semantics as they are currently interpreted. Such a step is > seen as a positive step in principle, while recognizing the > danger that > such additional assertions could in fact restrict semantics > as they are > used in practice. > > Danbri: One can say e.g. 'we believe these things are always in sync, > if not tell us' > > Bernard: Machine readable is normative, human readable is informative > ... go in this direction? > > Alistair "Which variant is authoritative" is a longer-term issue for > SKOS too. In SKOS, some constraints currently only described in prose > and would be hard to express formally; perhaps by using > SPARQL. The RDF > schema does not have enough information to specify all of the > constrains > -- e.g., broader/narrower, and "there should be only one > preferred label > per language". > > DanBri: RDFS had a class ConstraintResource > [End of minutes] > > First draft of minutes formatted by David Booth's scribe.perl > version 1.127 (CVS > log) > $Date: 2005/09/27 14:00:42 $ > > -- > Dr. Thomas Baker baker@sub.uni-goettingen.de > SUB - Goettingen State +49-551-39-3883 > and University Library +49-30-8109-9027 > Papendiek 14, 37073 Göttingen > > >
Received on Monday, 10 October 2005 14:28:44 UTC