All
Just catching up.
Could I strongly support the following. If there is one repeatedly
confirmed lesson from the medical communities experience with large
terminologies/ontologies/ it is to separate the "terms" from the
"entities". There are always linguistic artefacts, and language
changes more fluidly in both time and space than the underlying
entities. (In medical informatics this is sometimes quaintly
phrased as using "nonsemantic identifiers").
Regards
Alan
On 5 Jul 2006, at 22:43, William Bug wrote:
By the way, the "mapping" I refer to above linking instance data
where ever it may reside (primary data repositories, pooled/
analyzed/interpreted data, the scientific literature) to entities
in the ontologies requires reference to the lexicon - the TERMS
used to describe the ontological fundamentals by the scientists
reporting them. This is true whether an algorithm or a human is
trying to understand and interpret a collection of instance data in
the context of the relevant knowledge framework, even if that
framework resides in the head of the human researcher.
I like to think of this distinction as being very coarsely
analogous to the distinction between the physical data model in an
RDBMS and the many tools used to make that more abstracted,
normalized collection of related entities directly useful for
specific applications - e.g., SQL SELECT statements, VIEWs, and/or
Materialized VIEWS. Maintaining these as distinct elements goes a
long way toward ensuring the abstraction is re-usable for a large
set of applications, while simultaneously being able to support
each application's detailed requirements through custom de-
normalization.
This is why I like to keep the lexicon distinct from the ontology.
They are intimately linked. No ontology is free of lexical
artifacts (I'm not certain it can or should be), anymore than a
lexical graph can be assembled without representing semantic
relations. Analysis of the lexicon can inform how to adapt the
semantic graph in the ontology - make it more commensurate with the
current state of knowledge as expressed by domain experts, and
review of term use in the context of the ontology can be a great
help in creating effective, structured, controlled terminological
resources. However, the two types of knowledge resource are
constructed via different process, support different Use Cases, and
rely on different fundamental relations at their core, however
intimately they may be linked.
-----------------------
Alan Rector
Professor of Medical Informatics
School of Computer Science
University of Manchester
Manchester M13 9PL, UK
TEL +44 (0) 161 275 6149/6188
FAX +44 (0) 161 275 6204
www.cs.man.ac.uk/mig
www.clinical-esciences.org
www.co-ode.org
