- From: Booth, David (HP Software - Boston) <dbooth@hp.com>
- Date: Mon, 12 Feb 2007 02:10:52 -0500
- To: "Jonathan Rees" <jonathan.rees@gmail.com>
- Cc: <samwald@gmx.at>, <public-semweb-lifesci@w3.org>
> From: Jonathan Rees [mailto:jonathan.rees@gmail.com] > > Doing HTTP operations on an information resource, while abstractly > similar to answering SPARQL queries relating to it (in either case you > are learning something), seems to have a different feel given present > technology. The protocol used is HTTP and the stuff you get has types > (e.g. image, PDF) that are not best represented in RDF. Even if you do > a GET and receive RDF, the information you receive may or may not be > trustworthy and may or may not answer the questions you have - in fact > a common case (e.g. foaf:) is that the resource's RDF content is about > *other* resources, not the resource itself. > > Another way to say it: HTTP GET can only answer one question about the > resource. SPARQL (or other query language) can answer an open-ended > set of questions. Of course a GET can be parameterized with a query string, too, but perhaps a SPARQL query may be more better solution depending on the use case. > The GET problem seems pressing and almost tractable, > and we have a lot of experience with it. Finding SPARQL endpoints is > novel, everyone's using ad hoc solutions, and the need for shared > solutions is not so pressing. I am confused about the use cases that you are attempting to address. In reading the URI Resolution problem statement[1] the problem that is described sounds to me like what you are calling the GET problem -- not one that would require SPARQL endpoints. It sounds like you are trying to address a much broader set of use cases than is clear from the document. > > Be careful about the word "authoritative" - I know Tim B-L likes the > word, but authority is earned, not assumed; just because a host says > something about one of its resources doesn't mean what's said is true. > E.g., a server could easily be mistaken about authorship or licensing > terms for a document, and semantic-web phishing scenarios are pretty > easy to concoct, especially as more and more companies go bankrupt and > lose their domain registrations. That isn't quite what I meant by "authoritative". I meant it in the sense that (I think) the WebArch[2] uses the term. You are quite right that "authoritative" information served by a URI owner is not necessarily true, but it *is* authoritative in that the owner of the URI has the *authority* (i.e., is authorized by the WebArch and social convention -- see [2] ) to serve information that defines what resource the URI identifies. > > The issue is not primary vs. third party, but whether you should > believe what someone tells you. That's an orthogonal question. Well, yes and no. Trust is an important issue, and it may be important to be able to load some data from a source while excluding other data from that same source. SPARQL may be helpful for that. Is this what you were suggesting? This seems like a very different use case from what I understood by reading the URI Resolution Problem Statement[1]. Is this what you had in mind in [1]? OTOH, the issue of being able to efficiently retrieve primary information about a URI from the owner of its associated resource is very different from the problem of locating third-party information, even though the question of trust can apply to both cases. If the issue of trust is the primary problem that you are attempting to address, then I can understand lumping these cases together. But it seemed to me that the primary problem was much more around the mechanics and conventions for efficiently retrieving primary information, as suggested in the example given in the URI Resolution problem statement[1]: [[ An RDF file is composed using URL's that all resolve nicely. When years later someone tries to use the file, some of these same URL's are broken due to acquisitions, web site reorganizations, and changes of administration. All the linked resources are available, just under different URL's. How to make the user's application work without having to rewrite the RDF? ]] When I initially read the URI Resolution problem statement[1] I *thought* I had a reasonably clear understanding of the problem it is trying to address, but as the discussion has unfolded I am starting to think that my reading is significantly different than what the authors may have intended, and I'm not yet clear on what the intent is. Would it be possible to provide use cases that better clarify the intent? I, for one, would find that very helpful, and I wonder if some of the disagreement between Alan and Xiaoshu may also be rooted in different people making different assumptions about the problem you are trying to address. Thanks, David Booth 1. URI Resolution problem statement: http://esw.w3.org/topic/HCLSIG_BioRDF_Subgroup/Documents?action=AttachFi le&do=get&target=getting-information.txt or http://tinyurl.com/3a472e 2. WebArch on resource ownership: http://www.w3.org/TR/webarch/#uri-assignment
Received on Monday, 12 February 2007 07:11:05 UTC