RE: Question about namespace

For a good article on persistent identifiers, see the recent US Government Computer News (GCN) article:

http://www.gcn.com/24_24/tech-report/36726-1.html
("It Pays to Be Persistent")

Joe

Joseph Chiusano
Booz Allen Hamilton
O: 703-902-6923
C: 202-251-0731
Visit us online@ http://www.boozallen.com
 

> -----Original Message-----
> From: public-sws-ig-request@w3.org 
> [mailto:public-sws-ig-request@w3.org] On Behalf Of Jacek Kopecky
> Sent: Tuesday, August 30, 2005 2:46 PM
> To: santanche@ig.com.br
> Cc: public-sws-ig@w3.org; Tatiana Vieira
> Subject: Re: Question about namespace
> 
> 
> André, Tatiana, 
> 
> please see TimBL's view [1] on the distinction of URNs and 
> URLs, please note that the Web Architecture [2] doesn't 
> distinguish between such categories and please see section 
> 1.1.3 or the definition of URI (RFC
> 3986 [3]) that suggests that the distinction is not so clear 
> and that the generic term URI should be used instead.
> 
> In short, the distinction between URNs and URLs is not clear, 
> furthermore it's useful for URNs to be resolvable (to be 
> URLs) and it's also useful for URLs to be persistent (to be 
> URNs). Both are useful for usability of the Web and for 
> fulfilling of the normal person's
> expectations: that bookmarks will work for some considerable 
> time and that any URI, when put in the address bar of a 
> browser, will give me something useful.
> 
> Also, the point below that URNs are not restricted to a 
> physical location is somewhat dubious, as purl.org certainly 
> does have a physical location. What purl.org provides is 
> indirection, a known way to increase persistence, but one 
> doesn't need purl.org for that.
> 
> Finally, there is a urn: URI scheme and URIs in this scheme 
> don't necessarily contain any physical host information, 
> which may make them more persistent but it makes them a lot 
> less useful when someone sees such a URI for the first time.
> 
> Please consider using the term URI and making your http: URIs 
> persistent. 8-)
> 
> Hope it helps,
> 
> Jacek Kopecky
> 
> 
> 
> [1] http://www.w3.org/DesignIssues/NameMyth.html
> [2] http://www.w3.org/TR/webarch/
> [3] http://mirror.switch.ch/rfc/3986.txt
> 
> On Fri, 2005-08-26 at 16:31 -0300, Andre Santanche wrote:
> > Tatiana Vieira escreveu:
> > > Hi people,
> > >  
> > > As the topic here is namespace, let me ask a question. If a 
> > > namespace isn't necessarily an URL (it isn't necessary to be a 
> > > physical location), how can anyone discover the concepts 
> declared in 
> > > an ontology? I mean, how can I use a specicified 
> vocabulary defined 
> > > in any place in Web if I can't find it?
> > >  
> > > And, also, how can we be sure that namespaces will not 
> conflict, I 
> > > mean, that two diferent users will not put an igual namespace for 
> > > different documents?
> > 
> > URIs are divided in two categories: URLs and URNs. The URL adoption 
> > can be controlled by the URL owner, for example, my lab has an URL:
> > http://www.lis.ic.unicamp.br, and any sub-URL is agreed by the lab 
> > members. Additionally, I have a personal URL inside the lab 
> > http://www.lis.ic.unicamp.br/~santanch, then I can decide 
> the sub-URLs.
> > 
> > However, I prefer the use of URNs that are not restricted to a 
> > physical location, and can be directed to any URL you want. 
> There are 
> > many URN services. You could, for example, take your own 
> URN for free 
> > in http://www.purl.org/. The server guarantees that nobody 
> will take 
> > the same URN given to you.
> > 
> > > Thank you in advance,
> > > Tatiana.
> > 
> > Regards,
> > 
> > André Santanchè
> > 
> > 
> > 
> 
> 
> 
>

Received on Wednesday, 31 August 2005 12:18:25 UTC