background image
18
DigiCULT
Office of the e-Envoy
6
, the agency in charge of
Britain's e-Government programme, drove it with a
Web site called Govtalk
7
. `One big ASP database', he
called it. It carried the Government's interoperability
standard framework with a URL of: `... a great, big,
long string, something, something dot ASP'.That is
how this key piece of legislation is referred to, and
next week it will be something else!'
Dr van Kersen thought the new Web Ontology
Language with the transposed acronym, OWL, would
help. Italian ontology researcher Nicola Guarino
discussed the European Commission's On-To-
Knowledge project, its RDF tool Sesame
8
, and the
Ontology Inference Layer (OIL) language.
Dr Ross described the US Defense Department's
DARPA (Defense Advanced Research Projects
Agency) Mark-up Language (DAML) programme
and its DAML+OIL variant. Mr Degenhart-Drenth
highlighted the importance of protocols used in Web
Services, such as SOAP (Simple Object Access
Protocol) and UDDI (Universal Description,
Discovery and Integration), and also pointed to a
SPECTRUM XML standard for museums that he
helped write.Then there was the moviemakers' audio-
visual search standard MPEG-7 and the SMIL
(Synchronized Multimedia Integration Language).
No one mentioned SHOE (Simple HTML Ontology
Extensions), which was surprising, as the discussion
became more and more alphabetic and upper case.
O
NTOLOGY TUTORIAL IN
800
WORDS
Nicola Guarino brought the discussion back on
track.The ontology expert delivered a fascinating,
impromptu 800-word dissertation on ontology
genetics.
Ontologies, he said, started because it was realised
that controlled vocabularies, which worked well
enough for limited periods, needed something extra
to make them really useful.They needed clarification
of intended meaning.This could be achieved in
much the same way as dictionaries did it, by refer-
ence to other more basic terms.This was, he said,
the key point.
`Ontologies can work if the basic terms are
really used in a principled way.There is a hidden
assumption here that it is, indeed, possible to express
the meaning in terms of a relatively small set of
primitive terms.'
He explained further: `There are general terms that
have a universal meaning.Take the term "part", for
instance, or "set". Or take temporal relations,
"before". Suppose I have two different periods, the
Renaissance and another period, and suppose I say
that this period comes "before" the other one, do you
exclude the case whereby the two periods overlap or
not? This is just a matter of stipulation; this is a
general term that is not domain specific. I can simply
stipulate exactly whether the "before" relationship
between the two intervals includes the case of
overlapping or not. And I can do that by means of
axioms. Once you clarify the meaning of the basic
terms, topological relations, mereological
9
relations,
dependence relations, these kinds of things, then you
have the basic vocabulary that helps you to intro-
duce more domain-related things. And this is what
people are doing in the area of what are called
"Foundational Ontologies"... and this is what I am
doing. I believe this is the only way to solve the
problem of semantic interoperability. So, not just
controlled vocabularies but vocabularies that are
formally defined in minimal terms.'
Now it was clear, but would it be available to
heritage institutions? Dr Ross wanted to know if
fundamental ontologies of use to the heritage sector
already existed.What would they be? Before any
On-To-Knowledge
On-To-Knowledge is an IST RTD project that was
completed in June 2002.The project developed tools
and methods for supporting knowledge management
in large and distributed organisations.The technical
backbone of On-To-Knowledge was the use of
ontologies for the various tasks of information
integration and mediation. For the project's many
results, see their tools repository, project deliverables
and publications at:
http://www.ontoknowledge.org/pub.shtml
See also the On-To-Knowledge book `Towards the
Semantic Web. Ontology-driven Knowledge
Management'. J. Davies, D. Fensel, F. van Harmelen
(eds.). John Wiley, December 2002.
6
Office of the e-Envoy,
http://www.e-envoy.gov.uk/
7
Govtalk,
http://www.govtalk.gov.uk/
8
Sesame environment,
http://www.ontoknowledge.org/
tools/factsheet/Sesame.html
9
Mereology n.The formal study
of the logical properties of the
relation of part and whole.
Collins English Dictionary,
Third edition, Glasgow, 1991.