This is a composite of two messages I sent earlier and some thoughts that
transpired in the uos-convene phone conference on March 2.
Purpose: To create a map of the upper ontology landscape at several
levels:
- Broad descriptions of each upper ontology, indicating special domains
(such as time) included / excluded, level of detail, level of
formalization, and philosophical basis / rationale.
- Broad comparison, arranged in at least two ways: pair-wise
comparisons of the ontologies and an outline of issues / constructs with
an overview how each is treated in the different ontologies
- Detailed mapping that compares at the entity and relationship
level. Again, this could be done pair-wise, giving for each entity
and relationship of ontology A the closest corresponding entity or
relationship from ontology B, explaining agreement and disagreement as
appropriate. And this should be represented in the alternative
organization of taking each entity and each relationship, such as partOf,
and racing its treatment in all covered ontologies, pointing out
agreements and disagreements.
This map could be used to find a common subset, to select an upper
ontology for a given purpose, and for creating a "mix and
match" upper ontology by taking pieces from several upper
ontologies, providing these pieces fit together (which should be
decidable based on the map). (This is the idea of metadata profiles
in XML applied to upper ontologies or ontologies in general.)
A general method to arrive at such a map is as follows:
1 Collect
suggested upper ontologies - this is done by inviting the
"custodians". Might include ontologies that deal not with
all things but with often-used aspects, such as an ontology of time
concepts or space or general process description.
2 Compare and
determine differences
2.1
In elements
(presence / absence and, more difficult, definition)
2.2
in
relationships
3 Try to resolve
differences, creating a superstructure that incorporates
the
non-contradictory parts of various schemes
3.1
By adding
elements
3.2
By adding
relationships
4 Articulate the
remaining differences so that they are clearly understood.
Some issues that arise in such an effort are listed below (there are
surely more). These issues should be discussed at the Tuesday
meeting with the objective of either finding a tentative solution or
outlining a way for finding a solution. Put differently, the
meeting should start to hammer out a statement on the difficulties of
making these ontologies interoperable and the methods by which they can
be made more interoperable. This would include the determination of
- areas where there is no or little overlap with one ontology with any
of the others,
- areas where there may be agreement that one of the ontologies is
strongest,
- areas where the custodians may be willing to adapt,
- areas where people have strongly held different positions
Then issues of process
- How does one go about resolving differences?
- Can one agree on a common formal language (or on a common language
for more informal description) to describe the differences that cannot be
resolved so at least users of the ontologies know what the differences
are?
- What are next steps? Can two of the custodians start a pilot
project of reconciling some parts of their ontologies?
- How much effort is involved?
There may be more points to be considered. Perhaps we could
get some statements on these points before the meeting.
Dagobert Soergel
College of Information Studies
University of Maryland
4105 Hornbake Library
College Park, MD 20742-4345
Office: 301-405-2037 Home:
703-823-2840 Mobile:
703-585-2840
OFax: 301-314-9145
HFax: 703-823-6427
dsoergel@xxxxxxx
www.dsoergel.com
|