- From: Alan Ruttenberg <alanruttenberg@gmail.com>
- Date: Wed, 11 Apr 2007 22:13:46 -0400
- To: Jim Hendler <hendler@cs.umd.edu>, Holger Knublauch <holger@topquadrant.com>, public-semweb-lifesci hcls <public-semweb-lifesci@w3.org>, danbri@danbri.org
- Cc: Richard Cyganiak <richard@cyganiak.de>
Ho Ho. Funny you should mention this. I was just complaining about it yesterday. In this snippet it is me first, alternating with Richard Cyganiak. (The "weirdness" that Jim is referring to is that even requests for content-type: application/rdf+xml to the foaf URL return html) >> For example I am terminally confused by FOAF. What does the name >> "http://xmlns.com/foaf/0.1/" refer to? > > That's the FOAF vocabulary specification. A document, since GET > returns 200. It's available in HTML format, and may or may not be > available in other formats. > >> What does this mean (from foaf rdf)? <rdfs:isDefinedBy >> rdf:resource="http://xmlns.com/foaf/0.1/"/> > > The subject is defined by the FOAF vocabulary specification. > rdfs:isDefinedBy doesn't constrain the defining document to any > particular format. > >> How does a SW agent get the rdf for http://xmlns.com/foaf/0.1/ >> Organization ? > > It can't get the RDF since the FOAF folks have do neither GRDDL nor > a <link> header nor content negotiation. FOAF gets away with this > because everybody has to support FOAF, and so everybody just > hardcodes the URL to their RDF. Guess FOAF isn't quite getting away with it :) I'm not sure why they ever thought they could. Emanates from a criticism I make about content negotiation being bad semantic web practice. http://lists.w3.org/Archives/Public/semantic-web/2007Apr/0060.html It's my turn to respond. I'm reading about Content-Location headers, from RFC2616 - HTTP1/1. Here's a bit I'm currently trying to digest. It's not going down very well. > The Content-Location value is not a replacement for the original > requested URI; it is only a statement of the location of the > resource corresponding to this particular entity at the time of the > request. Future requests MAY specify the Content-Location URI as > the request- URI if the desire is to identify the source of that > particular entity. > > A cache cannot assume that an entity with a Content-Location > different from the URI used to retrieve it can be used to respond > to later requests on that Content-Location URI. However, the > Content- Location can be used to differentiate between multiple > entities retrieved from a single requested resource, as described > in section 13.6. Section 13.6 discusses the "Vary" header. More fun (but only if you care about what URIs refer to). -Alan On Apr 11, 2007, at 9:34 PM, Jim Hendler wrote: [snip] > However, I think the bigger issue here is that there were (and I > believe still are) some weirdnesses in the machine readability of > the FOAF namespace ( http://xmlns.com/foaf/0.1 ) and that a number > of systems have problems with it (I notice if I try to load it > directly into SWOOP I still get XML parsing errors). Lots of > systems have done various work arounds for this -- so when you > report your error to the Protege mailing list, you might also send > it to the FOAF one, we've been complaining about this for a couple > years now, maybe if some other folks yell as well we can get it so > that the most used Semantic Web vocabulary will actually conform to > the standards it promotes :-) > -JH > On Apr 11, 2007, at 7:35 PM, Noah Cohen wrote: >>> I have protege version 3.2.1 build 365 and JDK 1.5.0 >>> If I run this ontology through a verifier, it verifies the >>> ontology seemingly without a problem. >>> If i try to load the ontology directly from http:// >>> metacognition.info/ontologies/problem-oriented-medical-record.owl >>> I get some very interesting error: >>> WARNING: [ProtegeOWLParser] Warning: Trying to add import for >>> external resource: >>> http://purl.org/dc/elements/1.1/ -- >>> DefaultProtegeOWLParserLogger.logWarning() >>> INFO: [ProtegeOWLParser] Importing http://purl.org/dc/elements/ >>> 1.1/ (from Redire >>> ct to http://protege.stanford.edu/plugins/owl/dc/protege-dc.owl >>> <http://protege.stanford.edu/plugins/owl/dc/protege-dc.owl>) >>> The resource p1:chime has the rdf:type http://xmlns.com/foaf/0.1/ >>> Person which is >>> not a class but a >>> edu.stanford.smi.protegex.owl.model.impl.DefaultRDFUntypedRes >>> ource >>> Suggestion: In many cases the problem is a missing owl:imports >>> statement to the >>> classes file which defines the correct type of http://xmlns.com/ >>> foaf/0.1/Person >>> >>> It seems to me that it cannot distinguish the foaf Person class, >>> with or without the foaf imports statement. If someone could >>> please assist here, it would be of great help. Thank you in >>> advance, >>> Noah
Received on Thursday, 12 April 2007 02:13:54 UTC