[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: atom:category@scheme

On 5/10/07, Eric Scheid <eric.scheid@xxxxxxxxxxxxxxx> wrote:
> in XTM and others, the PSI isn't a sole attribute, but instead a given
> category could have multiple PSI, and hopefully one or two in common
> with the PSIs that you are using in your schema.

Eric is, of course, correct. An arbitrarily large, but hopefully small, number of subject indicators can be associated with a single entry in an ontology. In such a case, each of the subject indicators *should* be considered by the creator of the category element to be semantically equivelant. Thus, one might find the following:

<atom:category scheme="..bobs_ontology"
                        term="Communication.Publication.Book"
                        label="Book">
  <atom:link rel="psi" href="" http://de.wikipedia.org/wiki/Buch"/>
  <atom:link rel="psi" href="" href="http://en.wikipedia.org/wiki/Book">http://en.wikipedia.org/wiki/Book "/>
</atom:category>

What that says is that the concept or thing which is categorized as "Communication.Publication.Book" in bobs_ontology is referred to by humans as "Book" and is the same thing which is identified by the listed German and English Wikipedia URIs. If, in some other schema, (such as "Great Inventions") someone else was to create an entry that linked to either of the two Published Subject Indicator URIs, we would be able to infer transitive similarity between the term for a specific "Great Invention" and the term " Communication.Publication.Book" in bobs_ontology. In this way, of course, we can support cross-ontology reasoning, translation between languages, etc.

In a system that doesn't support PSIs or a similar concept, there is really no way to reason about the meaning of any term unless you have intimate knowledge of the schema that defines it. One might be able to establish precise equivelances between terms in a small number of "popular" ontologies, however, that is a very expensive process which requires a great deal of communication overhead and continued maintenance as terms are added or modified. It is better, I think, to let understanding emerge from an analysis of the encoding of the data -- even though that understanding might be a bit fuzzy.

bob wyman