One of the questions proposed in Track A (
Common,
Reusable Semantic Content) asks whether the reuse problems
(and perhaps their solutions) are different in the Linked Data
and ontology spaces.
Certainly, the uses of the two technologies are different
... as Linked Data is about the "links" and supplying
relatively simple semantic annotations and new links ... but
ontologies come down to T-boxes (more formal class,
relationship and/or axiomatic definitions) and A-boxes
(instance definitions). It is much easier to reuse small,
targeted schemas that define Linked Data and various
annotations (such as
schema.org) than it is to reuse
(typically much larger) foundational or domain-specific
ontologies.
In terms of time spent "getting up to speed", small,
targeted definitions always win. However, it is also much
more likely to be able to do reasoning over (and more complex
analysis of) ontologies and A-boxes. And, one can more easily
combine multiple ontologies (for example, with constructs such
as OWL's sameAs, differentFrom, disjointWith, ...) than to
combine (or reuse) multiple Linked Data schemas. In my
experience, I have seen developers typically pick one schema
and just stick with that.
Taking a lesson from the Linked Data world, I would posit
that the characteristics that make Linked Data schemas more
friendly and reusable could be applied to ontologies. That
would argue for:
* Smaller, more modular, targeted ontology fragments
* Separation of semantic (class and relationship)
definitions from the axioms that prescribe them
* (Perhaps) Definition of a context in which the axioms
apply (and the assumption that there may be more than 1
context and therefore more than one set of axioms)
Another lesson that the ontology world must learn is that
the fragments must be vetted, have real uses and sponsors,
and not devolve to multitudes of overlapping and (sometimes)
contradictory proposals. (I think that the biomed
BioPortal
community has done a good job with this.)
What do you think?
Andrea Westerinen