RDF - ISO/XML Topicmap Agenda - 20000918



A continuation of the conversations that started in Montreal at the Extreme Markup Languages Conference to increase knowledge and understanding about the relationships between the W3C RDF and ISO/XML Topicmap activities.

XML Topicmap Meeting - Update

Relationship of XTM and RDF

The actual and potential relationship of XTM and RDF was discussed,
since there had been public comment about this issue during the
Extreme Markup Languages Conference immediately preceding the XTM
meeting in the same hotel. Specifically, conference co-chair Michael
Sperberg-McQueen had suggested in his closing keynote that the RDF
people and the Topic Maps people should be locked in a room together
until they have harmonized the two standards. A "summit" meeting on
this issue has been proposed by Eric Miller, who would host such a
meeting at OCLC.

The AG, with the help of its three Subgroups, needs to: 

 - Understand the relationship, if any, between the XTM conceptual
 model and RDF conceptual model,

 - Understand what realistic opportunities exist for establishing one
 or more syntaxes that will be common to both Topic Maps and RDF, if
 any, and

- Understand the Use Cases, if any, that compel harmonization or
unification of Topic Maps and RDF around either their conceptual
models or their syntactic models, or both.  


XTM Agenda
Thu, 01 Jan 1970 00:00:00 GMT

Clarification regarding Topicmaps

Steve, Michel, could you reiterate again the differences between ISO Topicmaps and the XML Topicmap activities.

Recognized RDF Topicmap Relations


 Facing the conflict between Topic Maps and RDF head-on, the
 conference staged a debate between Eric "RDF" Miller of OCLC and Eric
 "Topic Maps" Freese of ISOGEN[10]. Freese and Miller provided this
 comparison between the two specs:

 Similarities between RDF and Topic Maps

 Both specifications

      are hard to read 
      share a goal: to tie semantics to document structures 
      provide a systematic way to declare a vocabulary and basic
      integrity constraints 
      provide a typing system 
      provide entity relationships 
      both work well with established ontologies

 The correspondences between the specs look something like this:

  RDF                     Topic Maps

  Resource                Topics
  RDF schema              TM templates (proposed)
  Properties              Facets and association roles
  URIs                    Topic identity, scope
  Reification             Association IDs

 Differences between the two specifications

      Topic Maps are not XML-specific and have so far been
      standardized for SGML only. The XML Topic Map activity under the
      GCA's IDEAlliance is drafting a proposal for such an
      implementation.  RDF is also not XML-specific, but to date has
      been implemented only in XML RDF now has which provides a
      standard way to express and link an ontology; such a schema is
      proposed for Topic Maps RDF uses XML linking, Topic Maps use
      HyTime linking Topic Maps have explicit scoping Topic Maps start
      with the abstract layer and (optionally) link to resources; RDF
      starts at the resource layer and (optionally) creates an
      abstract layer

 Modeling Topic Maps with RDF "loses the distinction between topics
 and resources," according to Freese. 

 In preparation for Montreal, he put out a call for suggestions on
 how to combine the two to end up with the best that each has to
 offer. Here are some of the suggestions:

      consider topics as collections of resources (anchors) or links
      such that one object can be a link by a link interpreter and a
      topic by a Topic Map interpreter 
      add RDF's frame-based notation to Topic Maps to attach
      properties to resources 
      model RDF as a Topic Map application, gaining the scoping,
      merging, and inheritance mechanisms

 David Dodds provided one view of an RDF/Topic Map alliance in his
 paper, "Simultaneous Topic Maps and RDF Metadata Structures in SVG."
 [11] In this application, he embedded Topic Map constructs in RDF
 metadata within SVG resources. With this notation, a graphics
 application would then know that a bar chart is a bar chart, and that
 each bar represents a certain scale and quantity. Since the RDF is
 embedded in a map, an external Topic Map processor can also
 manipulate the image.

 Freese's example of the best of both worlds would look like this:

   <topic xlink:type="extended"...etc...>
    <resource xlink:type="locator" xlink:href="...etc..."
         <dc:author>Dr Livingstone</author>

 This example attaches a set of properties to a locator, which is a
 link. The topic could also be an RDF frame and, therefore, could
 contain any kind of property.

 The reaction of the user community in Montreal was strong and
 unequivocal: merge the two or at least make them compatible.
 Among the desirable outcomes that were mentioned was a new
 syntax for RDF that would retain the graph notation but be less
 difficult to use.


XML.com - Part 2 - Going to Extremes
Thu, 01 Jan 1970 00:00:00 GMT

Case Studies - RDF

Useful simply to start listing examples:

Future Participation

Should we consider establishing a public archived mailing list for RDF <-> TopicMap discussions, or are we all happier working in private cc:'s initially? If public, whats the name, where?

Future Plans/Meetings

Where, when, does this forum (teleconference && IRC) work?

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