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[ontolog-forum] Planning for the scheduled discussion of 2005.04.28 : o

To: ontolog-forum@xxxxxxxxxxxxxxxx
From: Nicolas F Rouquette <nicolas.rouquette@xxxxxxxxxxxx>
Date: Thu, 14 Apr 2005 17:53:52 -0700
Message-id: <425F10A0.50507@xxxxxxxxxxxx>
As the proverb goes, preparation is key.
To plan for the upcoming scheduled technical discussion,
I'd like your input to focus the discussion down to a reasonable scope.    (01)

-- Nicolas.    (02)

---------------------------------------------------------------------------------------------    (03)

Topic: Ontologies, reasoning & tagging    (04)

Session moderator: Nicolas Rouquette    (05)

Background:    (06)

1) OWL is the de-facto common ground for relating external information 
via tagging to an ontology where ontology-based reasoning has a useful 
application-specific role.
2) Tool support for OWL-based development and reasoning has progressed 
to the stage where OWL has become a practical technology, almost 
3) There is plenty of lattitude for applying this technology in a 
practical sense: this is both promising (e.g., innovative methodologies) 
and concerning (e.g., project failures)    (07)

Goal: assemble a panel of experts to discuss:    (08)

a) selecting what useful functions can ontology-based reasoning have 
w.r.t. application-specific issues, questions, problems    (09)

examples:    (010)

a.1) ontology development support
=> reasoning: -- see classification here: 
=> tools -- see a list here: http://www.w3.org/2004/OWL/#paa    (011)

a.2) semantic query
=> reports, extracting a specific subset of an ontology -- see document 
generation here: 
=> tools -- see list above
=> query languages & tools
  comparison: http://www.aifb.uni-karlsruhe.de/WBS/pha/rdf-query/
  the new kid on the block: sparql
  see: http://www.aifb.uni-karlsruhe.de/WBS/pha/rdf-query/
  why should you care? -- see: 
http://lists.w3.org/Archives/Public/www-rdf-rules/2005Apr/0001.html    (012)

a.3) validation / verification
=> consistency/integrity checking
=> this is big problem but one that can quickly escalate into fierce 
arguments --- see: 
  e.g., is there a sensible strategy to use a (meta) ontology with which 
one can describe the kind of consistency/validation/... criteria we want 
a (lower) ontology to have?    (013)

b) handling expressiveness / modeling / representability issues    (014)

=> sometimes, OWL isn't enough (because of limited expressiveness) to 
describe complex important application-specific notions.
  eg. -- see the session on "biomedical ontologies" here: 
http://protege.stanford.edu/conference/2004/schedule2.html#thursday    (015)

examples:    (016)

b.1) a possible next step: use an "upper" ontology that is sufficiently 
expressive to adequately capture such complex application-specific notions.    (017)

=> how?    (018)

b.2) annotation strategy
 concern: annotations are currently "ignored" because the meaning of an 
annotation depends on what annotations are used for and what meaning is 
assigned to them
 possible strategy: develop an "ontology" that describes the meaning of 
an annotation
 motivation1: the meaning of an annotation is clear
 motivation2: use the meaning of an annotation to select which 
annotation(s) are relevant/useful for a specific reasoning purpose    (019)

=> including an annotation ontology can easily lead to a logical theory 
that is no longer OWL-DL but OWL-Full    (020)

c) selecting among strategies for capturing application-specific 
semantics into a useful form for such reasoning functions:    (021)

c.1) tagging application-specific domain concepts & data with 
ontological annotations
c.2) splitting the application-specific domain into different ontologies 
(e.g., separating the simple stuff from the complex stuff)
c.3) formalizing the complex stuff with a different kind of theory    (022)

=> annotation is a common example of a practical strategy (see best 
practices guidelines for representing classes as property values)    (023)

=> is using an "upper" ontology like SUMO, DOLCE or PSL for annotation 
purposes  a sensible strategy?    (024)

possible motivations:    (025)

* reusing/leveraging high-quality ontologies whose semantics have been 
carefully and rigorously defined.
* the reasoning problem involves domain-specific knowledge beyond the 
scope of the ontology
    (e.g., planning as a form of application-specific reasoning style in 
the context of web services    (026)

http://www.daml.org/services/use-cases/language/swsl-usecase/Composition.htm)    (027)

=> the semantics of such "upper" ontologies (e.g. SUMO, DOLCE, PSL) 
require languages that are more expressive than OWL (e.g., KIF)
     catch 22: reasoning in the context of expressive ontologies can 
quickly turn into an excercise in theorem prooving
     theorem prooving isn't practical in many cases: theorem proovers 
require a lot of "guidance" from a sufficiently skilled / knowledgeable user    (028)

=> are there circumstances in which theorem prooving can be reasonably 
automated w.r.t. ontologies that are formalized in a suitable way?    (029)

alternative strategies without theorem prooving:    (030)

=> if reasoning is the means to an end (e.g., answer a question about an 
ontology, a model built w/ the ontology, ...)
      can we extract the relevant portion of the ontology that is 
necessary w.r.t. reasoning about a specific question?    (031)

possible motivation: reasoning w/ the full ontology may be overkill; 
reasoning w/ the relevant portion of the ontology ought be a simpler and 
tractable problem    (032)

=> are there practical strategies for "extracting" a subset of an 
ontology that is logically relevant & useful w.r.t. a specific reasoning 
problem?    (033)

---------------------------------------------------------------------------------------------    (034)

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