RE: Linkbases, Topic Maps, and RDF Knowledge Bases -- help me

[Didier PH Martin <martind@netfolder.com>]

Hi Ouche

Ouche said:
Why is this "very feasible" in RDF?  It's built in as well:

<rdf:Description
  about="http://spam.com#Malatesta"
  type="http://art.org#Patron">
[...]

Didier replies
I know you wont agree on this but what I would like to see is
<topic xlink:type="extended" etc...>
<resource xlink:type="locator" rdf:type="http://art.org#Patron"
xlink:href="about="http://spam.com#Malatesta">
.... property list for this frame .....
</resource>
</topic>

In some ways an rdf element is a frame (like AI frames), if rdf:type is
present it is no longer a free form frame but more a defined record, if the
rdf:type is not present, it is a free form frame. This said, now the problem
is for an RDF engine to recognize the this particular element is an rdf
element.

possible solutions:
a) rdf recognizes xlink:href as equivalent to the "about" attribute, this
would imply that an rdf frame is a link. hummm, not convinced that this is a
good idea because it does not make sense for the other RDF usages.
b) to define a free form type like for example
rdf:type="http://www.w3.org#frame". In this case we state that this element
is a free form frame and not a record defined by a type. But if the rdf
element is conformant to a certain structure and is therefore an instance of
a certain class, then we would have instead
rdf:type="http://art.org#Patron". I prefer this solution since it allows us
to include a free form or defined collection of properties for a particular
"locator".

So
a) free form "frame" (like Artificial Intelligence frames)
<topic xlink:type="extended" etc...>
<resource xlink:type="locator" rdf:type="http://www.w3.org#frame"
xlink:href="about="http://spam.com#Malatesta">
.... property list for this frame .....
</resource>
</topic>

b) defined record or instance of a particular class
<topic xlink:type="extended" etc...>
<resource xlink:type="locator" rdf:type="http://www.w3.org#frame"
xlink:href="about="http://spam.com#Malatesta">
.... property list for this frame .....
</resource>
</topic>

Now remains the mechanism to link topic together. I would say that a "link"
would probably be a good solution since we link to things together (low
level mechanism) with a certain meaning (semantics): an association.

Use case:
A query is sent to a search engine (with an HTTP request). This latter
returns a set of resources about a topic expressed as above. At the minimum
this topic can be interpreted as a link. At the most as a topic map. If this
topic map includes associations between the topics, an engine able to
interpret this allows the user to ask questions like "what is related". Thus
for instance, the engine shows the result as a context menu, a menu option
is a "what's related" which shows a secondary context menu listing the
associations. if the interpreting engine is a topic map or semantic link
engine (I do not know how to call this gizmo) then it behaves as previously
described, otherwise it just act as an xlink engine probably showing only
the list of resources.

I am not trying to convince you Oche, just showing that if elements could
inherit the rdf frame behavior (defined record or free form frame) this
would lead to a tremendous useful thing for knowledge management.

cheers
Didier PH Martin
site: http://www.talva.com
email: martind@netfolder.com
book: Professional XML (wrox)
next conferences: xml devcon 2001 New York
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