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Use cases & language experiences from OntoWeb members

From: Frank van Harmelen <Frank.van.Harmelen@cs.vu.nl>
Date: Sun, 30 Dec 2001 17:59:29 +0100
Message-ID: <3C2F47F1.588F54E9@cs.vu.nl>
To: www-webont-wg@w3.org
	
The following use-cases for a Web-ontology language were collected in the
meeting of the OntoWeb Special Interest Group on Ontology Language
Standards during the OntoWeb meeting in Amsteram early December. 

These notes will also soon appear in hypertextified form on the SIG's
website, at http://www.cs.man.ac.uk/~horrocks/OntoWeb/SIG/, but because
of the short timescales I thought it best to forward these notes to the
WebOnt group already.

I thought they might be useful (although late) input to the use-case documents and the language-experience document from Mike. 

Frank.
   ----

 (These are the rough notes taken during the presentations by me, so all mistakes in these notes are mine.)

The following use-cases were presented:

     - Computer System Management (IBM Rome)
     - Multi-media generation (CWI Amsterdam)
     - Knowledge management and portal applications (AIFB Karlsruhe)
     - Document annotation and retrieval (Prague)

A final discussion concerned the introduction of reification into an
ontology language.

Computer system management
--------------------------

Guido Vetere from IBM Labs Rome presented work they have been doing
since 1996 on a computer system management ontology, which describes
computer systems, problems and failures. The ontology was modelled in a
Description Logic style. This turned out to be easy. There was no strong
commitment to Description Logics, and their full power was not really
fully exploited; for browsing this was not necessary, but the
Description Logics were useful for reasoning. The ontology modelling
took as in put the "Common Information Model" (see
http://www.dmtf.org/standards/standard_cim.php), developed by large IT
producers (Microsoft, Intel, IBM), with 300 concepts on IT products and
processes. This fitted well into a Description Logic. A problem for
users was how to find relevant concepts without browsing. This is now
done via attaching to WordNet. A new problem raised in this approach was
that current ontology languages lack mechanisms for associating lexical
descriptions with concepts. A notion of "linguistic signs" is needed
because different user communities have different such "signs". The
group is currently not using any of the publicly available ontology
languages, but has programmed the application in a home-grown datamodel
with a private API.


Multi-media generation
----------------------

Jacco van Ossenbruggen of CWI Amsterdam presented the groups work on
multi-media presentation generation: their intended scenario is as
follows: in response to a query to a database, a user gets back a set of
media-items; the challenge is then to combine these items in a coherent
multi-media presentation that answers the query. For this, one need lots
of information about these multi-media-items and their relations. Some
of the expressivity requirements are:

     - the need for different ontologies at different levels, eg:
       media-specific, domain/content-specific, presentation-specific;
       
     - the need to reason about all these ontologies combined. The
       reasoning they need combines reasoning at class and instance
       level. No subsumption style reasoning seems required.
       
     - the need to use large existing ontologies, but typically the only
       need parts of these large ontologies. Thus, there is a
       requirement for some information-hiding/modularity concept;
       these different existing ontologies are also likely to come from
       different communities, so there is a need syntactic
       translations. 
       
     - Finally, the group also wants to re-use the “input
       metadata” from the databases and include them into the output
       presentations. Again, this requires mapping and import
       mechanisms. 
      
Currently all the work of the group is encoded into home-grown ad hoc
technical solutions. However, they are keen to move to a more clean
declarative representation.


Knowledge-management and portal applications
--------------------------------------------

The AIFB group of the Univesity of Karlsruhe presented some of their
work in ontologies for knowledge-management applications and portal
building:

     - They constructed a skills management ontology for Swiss Life as
     part of the On-To-Knowledge project. This ontology is intended to
     be used for gap analysis (= missing skills in the organisation),
     and expert-finding. 
     
     -They constructed a ontology of  tourism information (1200
     concepts, 300 relations). This was a large multi-person effort,
     and is used for portal construction, in particular to support
     query-answering 
     
     - The ontology for the Ontoweb portal was built to support a similar task

     - Another ontology supports their own AIFB portal with access for
     different navigation structures 
     
Some of their conclusions from this work are: 

     - There is a need for both schema-queries and instance queries, as
       well as combinations of these two;
       
     - keep it simple (e.g. required for Swiss Life), possibly with more
       complicated layers,
       
     - Until now, they have only had a need for named concepts
       only. They have found no use for the "anonymous classes" or
       "class constructor" expressions as found in Description Logics

     - They have a need to be able to generate unique identifiers for
       instances, with different multilingual rendering required.
       
     - They have mainly been using F-Logic as their ontology modelling
       language. This usage was fairly simple in tourism domain, and
       more sophisticated in the AIFB portal (e.g. use of transitive,
       symmetric and inverse relations) 
     
Until now, all these ontologies were their own constructions. They have
considered using existing ontologies but until now have always opted for
constructing their own ontologies.

Ontoprice presented their "time-to-research" portal, which is intended
for IT-industry analysts (185 concepts). Particularly interesting about
this ontology is that it contains lots of rules, e.g rules for defining
the notion of a "competitor" in terms of relations between other
concepts.


Document annotation and retrieval
---------------------------------

Vaclav Lin from Prague briefly announced their plans for annotating
reports with Knowledge and Data Discovery (KDD) results of data-sets.
Their intention is to annotate such KDD reports with statistical
information in order to enable content-based document retrieval.


Reification
-----------

Enrico Motta from KMI/OU-UK described their work on annotation of
on-line contents. He argued strongly for reification features as a
necessary feature of ontology-languages for such applications. Remarks
from the audience suggested that such features are also needed in
agent-based applications. Rudiger Klein from Daimler-Chrysler argued
that he would need 2nd order constructions (similar to but not the same
as reification).

Examples where he would need this are:

     - to qualify properties as being of a certain type
       (e.g. structural, chemical),
       
     - to select different views on same ontology;
     
     - for extensibility (e.g to add time-specific constructs to an
       ontology language if the language itself does not provide them);
     
     - to store meta-data in the ontology (e.g source, author,
       reliability);
       
     - even in simple application like annotating abstracts such
       features would be needed (e.g. to model argumentative
       structure). 
      
An extensive discussion followed how much of this could be done with the
subproperty hierarchy, and how much of this could be done with
meta-classes (such as the mechanism provided by Protege). Various people
also pointed out that many of these reification and 2nd order
constructions are in fact rather simple varieties, and that they need
not be cause for computational problems.
Received on Sunday, 30 December 2001 12:01:03 GMT

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