[RDF] Re: Authorization

[Jonas Liljegren]

Graham Klyne <GK@Dial.pipex.com> writes:

> At 05:36 PM 1/1/01 +0100, Jonas Liljegren wrote:
>
> >The versioning system and the trust system are two aspects of the same
> >thing.  To trust or not to trust is just one view. Other views is to
> >see what is stated in diffrent times or from diffrent perspecives or
> >scenarios.
> 
> Hmmm...   at one level I agree with this, but I was trying to suggest that no
> single model will fit all cases.  Rather, I see in RDF the potential to
> describe and integrate multiple models, without prejudice.  So, in a sense,
> RDF is your 'general model'?

Yes of course.  But in Wraf, I want to provide an flexible
infrastructure on which to build service applications.  That's why I
introduce RDFS-classes to represent sessions, uesers, information
requests and more.

The versioning and trust system should be implemented in a way that
you can replace it with another, better suited to your needs.  But I
will in any case create one system flexible enough to use for the
application i created Wraf to create.

        http://jonas.rit.se/project/RDF-Service/doc/html/hdc.html

It should support multipple languages. Multipple versions.  And the
user should see the version blessed by the administrators.


> >The context is a hierarchy of contexts. It starts with the session,
> >defining the time and place for the conversation.  Here we identifies
> >the requestor agent and the service.  A specific request adds to the
> >context.  There can be a series of questions and counter-questions,
> >all within the context.
> 
> Sounds reasonable.  Your hierarchy of contexts is consistent with
> McCarthy/Guha's work, in that any statement is asserted within a 'nest' of
> contexts.  However, I think that this doesn't necessarily mean that contexts
> always form a strict hierarchy.

No. Rather I mean that the context of a request includes who the
requestor is.  Metadata about the requestor can be used to get
implicit criterions for the request.  One such criterion would be the
prefered language of the response.

The heiarchy was a thought about how to handle contradicting data.
Let's say that you usually like your HTML pages formatted with heavy
graphics and stuff.  But for this session, you have asked for smaller
faster pages, because you are using a handheld mobile device.  The
statements in the session should have precedence over the general
preference for more graaphics.

I could think about several ways to make this happen.  

One such tactic would be to looking in the session metadata before the
person metadata and don't look futher if the specific preference was
found there. Hmm...

Another would be to use exceptions.  The logic could be to make a
statement and say that it should override over such statements, but
only for the current session. -- Yes. That sounds right.  It would be
the same infrastructure as that used for version handling.

        http://jonas.rit.se/project/RDF-Service/doc/html/context.html


> >So what could we use for model as a testcase for this?  Something
> >simple and useful for a typical community database.  Maby a use of
> >ratings to sorting or filtering discussion entries, a little like
> >slashdot, but simpler?
> 
> I feel that there is more groundwork to be done before I can seriously address
> some of these questions.  OTOH, if you have a well-specified use-case, maybe
> we can work together to try and model it?


I think that it's important to include this functionality into Wraf as
soon as possible.

But in order to build test cases, I will ned basic presentation
functions.  That will be the next step.

        http://jonas.rit.se/project/RDF-Service/doc/html/presentation.html


-- 
/ Jonas  -  http://jonas.liljegren.org/myself/en/index.html