Subject: Re: Framework for capabilities and user

From: [email-masked] (Reynolds Franklin NRC/Boston)
Date: Tue, 20 Oct 1998 17:41:08 -0400

In General:

We agree that the work of each can complement the other.  In
those situations where our work overlaps we definitely want to
avoid gratuitous incompatibility.  At least two of the authors
(including myself) of the CC/PP proposal will be in Orlando
for the IETF meeting. We are looking forward to meeting and
working with you and the other members of your group.

If I understand your discussion of feature collections and feature
sets properly, you seem to feel that RDF may be a reasonable
 way to encode feature collections. If we are careful, we may be
able to provide some level of compatibility or interoperability
between our RDF approach and the CONNEG approach.

You correctly observe that we use RDF to describe features and
preferences, but we do not describe rules for matching the features
of the content to the preferences of the user. Hopefully we will be
able to rely on strategies developed by others, such as the
CONNEG algebra.

In Particular:

>1. It's not accurate to characterize our work as an extension of MIME.  The
>conneg framework stands independently of MIME (though I would expect it to
>be used in conjunction with MIME).

My mistake.  Fixed in the next release.

>(BTW: the CC/PP document made mention of tokenized XML;  can you supply a
>reference for this please?)

http://www.wapforum.org/docs/technical/wbxml-30-apr-98.pdf

>(1) It was not clear to me how the "table of tables" data model was used.
>I could see the use of a single table to describe some set of attributes,
>but beyond this I could only see a "set of tables" being used to collect
>individual tables from different sources.

"Set of tables"  or perhaps a "collection of tables" would more
accurate. Fixed in the next release.

>(2) In looking at the second example in the paper ("indirect references"),
>I could not see how the referencing URI was related to the related profile.
> I assume that the given profile is made accessible at the appropriate URL.

I am not sure I understand the question. Consider a simplified version
of the indirect reference example in the proposal:

<RDF xmlns="http://www.w3C.org/TR/WD-rdf-syntax" prefix="RDF"
   xmlns:PRF="http://www.w3C.org/TR/WD-profile-vocabulary">

<Description ID="hardware platform">
    <Description ID="defaults">
        <PRF:HardwareDefaults = "http://www.nokia.com/profiles/2160" />
    </Description>
</Description>

<Description ID="software platform">
    <Description ID="defaults">
        <PRF:SoftwarePlatformDefaults = "http://www.symbian.com/epoc/profiles/PDA" />
    </Description>
</Description>

Would a slightly altered version that explicitly collects all the
other descriptions within a single profile description make
things more clear? Example:

<RDF xmlns="http://www.w3C.org/TR/WD-rdf-syntax" prefix="RDF"
   xmlns:PRF="http://www.w3C.org/TR/WD-profile-vocabulary">

<Description ID="capability and preference profile">
     <Description ID="hardware platform">
         <Description ID="defaults">
             <PRF:HardwareDefaults = "http://www.nokia.com/profiles/2160" /> 
         </Description>
     </Description>

     <Description ID="software platform">
         <Description ID="defaults">
             <PRF:SoftwarePlatformDefaults = "http://www.symbian.com/epoc/profiles/PDA" />
         </Description>
     </Description>
</Description>

Franklin Reynolds
Nokia Research Center

---

From: Graham Klyne <[email-masked]>
Date: Wed, 21 Oct 1998 17:15:41 +0100

>working with you and the other members of your group.

Excellent!  I hope to meet you there.

I have made a first tentative stab at reconciling some aspects of our
approaches -- submitted today as I-D <draft-ietf-conneg-w3c-ccpp-00.txt>.
It's fairly rough -- I am mainly attempting to get some ideas out in the open.

> way to encode feature collections.

Yes.

"Feature sets" (i.e. sets of possible feature collections) are more
challenging.  But I think there may be a way (see the I-D mentioned above).

>If we are careful, we may be

I think so.

>http://www.wapforum.org/docs/technical/wbxml-30-apr-98.pdf

Thank you.

>accurate. Fixed in the next release.

OK, I understsand.

>I am not sure I understand the question.

On re-reading the ccpp paper, and looking at the RDF work, I think that
maybe I had simply missed the extent to which you treat every resource as
being directly accessible via by the web and adressed by URL.

If you can confirm that, in your section 4.2, the "profile made available
by the hardware vendor" is accessed at <http://www.nokia.com/profiles/2160>
that would answer my question.

If not, then my question would be:  in the RDF resource ID="Hardware
platform", to what does the statement
<PRF:HardwareDefaults="http://www.nokia.com/profiles/2160"/> actually refer.

I'm sure this is a very simple thing I am missing, or am unsure about.

However, I do now have another question about your examples:

If I read RDF correctly, the <Description ID=...> construct defines a new
RDF resource.  Looking at your first example (section 4.1), the nested
descriptions of "defaults" within "hardware platform" seems to suggest
creation of a new RDF resource within the "hardware platform" resource.
But this new RDF resource is not obviously associated with a "predicate"
(or "propName").  But the RDF syntax seems to require that every value
within <description>...</description> must be associated with a "propName"
(what I understand to be an RDF predicate identifier).

I am looking particularly at the syntax productions for "description" and
"propertyElt" in section 6 of the RDF model and syntax specification.

Am I missing something here?

#g

------------
Graham Klyne
([email-masked])