Ontological distance

[Tony Linde]

It strikes me that, in order to have an ontology-based system make
suggestions about a given topic (of the type: also look at topic X), we
need a concept of 'distance' between classes. 

Would it be possible to add a 'closeness' factor to a relationship-type.
This factor would have values (for simplicity) of [positive, neutral,
negative]. Any two classes tied by that relationship-type would be
'close' if the closeness factor of the relationship-type was positive
and 'far away' if negative; if the factor was neutral, then nothing
could be said about their closeness.

Subsumption relationships ('is a type of', 'is a component of') would
most likely be positive, while antonymic relationships ('is distinct
from') would be negative relationships. Neutral relationships might be
??? (can't think of one :).

A class would then be closest to other classes with which it had the
greater number of relationships with 'positive' closeness over those
with 'negative' closeness (eg distance to the class could be computed by
number of positive relationships minus number of negative
relationships).

Is this reasonable? Has 'distance' been defined already? Is it feasible
(eg with OilEdit and DAML+OIL, say)?

Cheers,
Tony. 

__
Tony Linde                       Phone:  +44 (0)116 223 1292
AstroGrid Project Manager        Fax:    +44 (0)116 252 3311
Dept of Physics & Astronomy      Mobile: +44 (0)7753 603356
University of Leicester          Email:  tol at star.le.ac.uk
Leicester, UK   LE1 7RH          Web:    http://www.astrogrid.org