Re: Modeling a specific construct - please help

On Tue, Sep 15, 2009 at 4:24 AM, Alan Rector <rector@cs.man.ac.uk> wrote:
> Well, no, you cannot (validly) conclude this. This is a non-monotonic
> inference, which is not supported by the OWL semantics. While it may work in
> particular cases where you know that your data is complete in the required
> sense, it is not good practice to use such inference patterns in OWL, as
> they will (not may, but WILL) break in some cases. Think building a glass
> building over a known seismic fault.
>
> Pat Hayes

> The difficulty with such reasoning patterns is that they only work when you
> can
> complete the knowledge base so that it is fully constrained.
> In most of our biomedical models, we can rarely be certain enough
> that all possibilities have been covered to reason that the only
> possibilities left over are true, only that they might be and may
> ]be worth further investigation.

True, but I've found (in practice) that non-monotonic reasoning
matches well with the intuition behind clinical medicine and the way
electronic patient data can be recorded as RDF (mostly using strict
data entry controls where it is important to assume at least a portion
of the data is complete in order to make reasonable inferences from
it)

> Although we have sometimes used this kind of reasoning on very restricted
> data entry problems with multiple constraints where we can be sure that they
> can all be covered.  In those cases the non-monotonicity is an advantage,
> although I would try to confine it to increasingly large queries rather than
> the KB itself. As we learn more, we add it to the query, so that query gets
> larger and the number of
> possible answers to the remaining questions gets fewer.
> This sort of reasoning used to be supported in the Protege Query tab, but is
> no longer.
> Regards
> Alan

-- Chimezie

Received on Wednesday, 16 September 2009 14:51:36 UTC