Re: external resources reifying

Jean,

Thanks for your answers... I'll try to provide some clarification.
At this time subject identity is only used for the core ontology and potential
published subjects (topic maps concepts, languages, countries, domain recognized
nomenclature...). I must confess that I have absolutley not envisaged the
use of subject identity as you suggest it... but why not....

Jan Algermissen wrote:
> Hmm...I think I don;t really understand what you
> mean by 'internal' and 'external' resource. Can
>   you explain these terms.
In my view:
 Internal occurrence refers to information contained in the topic maps (topicRef
or resourceData)
 External occurence refers to information sotred outside (resourceRef)
> >   
> This seems the right way to do it (with XTM), although I am not clear about what you mean by "have occurrences pointing to these topics". I think you mean
>
> <topic id="a-document">
>   <subjectIdentity>
>     <resourceRef xlink:href="" class="moz-txt-link-rfc2396E" href="http://foo/doc1.xml">"http://foo/doc1.xml" />
>   </subjectIdentity>
>   <!-- meta data goes here as occs -->
> </topic>
>
> <topic id="valve16">
>   <occurrence>
>     <resourceRef xlink:href="" class="moz-txt-link-rfc2396E" href="http://foo/doc1.xml">"http://foo/doc1.xml" />
>   </ocurrence>
> </topic>
No, not exactly. It would rather be something like:

<topic id="a-document">
    <instanceOf><topicRef xlink:href=""></instanceOf>
   <occurence>
   <!-- the first occurrence is the address of the reified external resource
-->
        <instanceOf><topicRef xlink:href=""></instanceOf>
         <resourceRef xlink:href="" class="moz-txt-link-rfc2396E" href="http://foo/doc1.xml">"http://foo/doc1.xml" />
    </occurrence>
    <!-- the other occurrences are of type internal and provide metadata
about the external resource -->
   <occurence>
        <instanceOf><topicRef xlink:href=""></instanceOf>
           <topicRef xlink:href="">
      </occurrence>
   <occurence>
        <instanceOf><topicRef xlink:href=""></instanceOf>
          <resourceData>100x200</resourceData>
     </occurrence>
</topic>

<topic id="valve16">
    ...
    <occurrence>
        <instanceOf><topicRef xlink:href=""></instanceOf>
        <topicRef xlink:href="">
    </occurrence>
</topic>

> Why?  Can you give an example of what you have in mind?
As you see above, the metadata about the resource are separated from the
occurence in the topic "valve16".

Now, imagine that two topics are using the same external resource:

<topic id="valve16">
     ...
     <occurrence>
         <instanceOf><topicRef xlink:href=""></instanceOf>
        <scope><topicRef xlink:href=""></scope>
       <topicRef xlink:href="">
     </occurrence>
 </topic>

 <topic id="motor4">
      ...
      <occurrence>
          <instanceOf><topicRef xlink:href=""></instanceOf>
         <scope><topicRef xlink:href=""></scope>
        <topicRef xlink:href="">
      </occurrence>
  </topic>

But each topic would use differently the resource, as indicated by the scope
of  each occurrence. One sees the graphic as a design description and the
other one as a functional description.

My initial question was the following: in a sense, the various "use" of the
external resource can be seen as metadata of the external resource. So, I
would like to know how I could include them in the topic "a-document" and
not have a duplicate information in each refering topic.

As a matter of fact, if another topic map is build with the same external
resource, It would be interesting to start not only with the external resources
but also with all the topics of type external that reified these resources.

> >   
> Is the topic map the primary storage for all the information or is it an intermediary
> format between some database and your information system?
It is foreseen that the produced topic map would be feed in a database.
The resources would stay as external xml files.

> > - the scope of the topic T(R) is not used (at this time);
> >   
> Huh? Topics don't have scope...what do you mean?
No.. they can have scope, but I have not make use of it  yet to solve this
issue.. but they could be part of the solution
> > - an occurrence of type external for this topic provides the link to the external resource;
> > - other occurrences of type internal provide metadata about the external resource like: language, size, origin, date of last update...;
> >   
> Hmm...if you use the type of an occurrence for internal/external....how do you express that it
> is size,origin, date etc...?
Inside the resource reifying topic, occurences types are more precise and
indicate the kind of metadata provided (see in the sample above).

Olivier.

--
O. Lamborelle
System & Operations Engineer

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