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use-case format

From: Guus Schreiber <schreiber@swi.psy.uva.nl>
Date: Fri, 30 Nov 2001 15:41:07 +0100
Message-ID: <3C079A83.D44123D8@swi.psy.uva.nl>
To: WebOnt WG <www-webont-wg@w3.org>
Dear WebOnt colleagues,

I am a bit worried about the "gap" between the use cases and the
language definition we have to deliver.  I would be in favor of moving
as quickly as possible to concrete use cases in a specific domain, so
we can clarify the WebOnt requirements.

Having said this, I feel obliged to make a first, very preliminary,
proposal for a use-case format:

  TASK: 
  the application task using the ontology, e.g. annotating
  a digital image collection  

  EXAMPLE DOMAIN: 
  a particular domain for which you provide concrete examples,
  e.g. images of Chinee porcelain

  TYPICAL USER: 
  e.g., museum personnel having to index images

  ONTOLOGY SAMPLES: 
  some selected knowledge fragments which would typically need to be
  presented in WebOnt, e.g. the AAT color hierarchy.
  This should typically be the most comprehensive part of the use case.

  WEBONT REQUIREMENTS: 
  a WebOnt requirement arising from the use case, e.g. a UML-type
  distinction between abstract and concrete classes

Please feel free to shoot at this. As an example, I reformulated part
of my own use case in terms of this format [see end of message]. 

Hope this is of some use. 

Guus Schreiber

------------------------------------------------------------

TASK: searching a digital image collection

EXAMPLE DOMAIN: museum collection of images of antique furniture 

TYPICAL USER: lay person with some basic knowledge of the domain,
looking for some piece of antique

ONTOLOGY SAMPLES:

The basis of our ontology is formed by the Art and Architecture
Thesaurus (AAT) [1] constructed by the Getty Foundation, which
provides a highly structured hierarchy of some 120.000 terms to
describe art objects (art categories, materials, styles, color,
....). We also have a description template for antique furniture based
on the VRA 3.0 standard [2], which is basically a refinement of Dublin
Core for art-image annotation

Let's for the moment assume we can represent AAT and VRA in
WebOnt. For effective search support we need to add domain knowledge
to this ontology.  This knowledge typically takes the form of
inter-slot constraints within the image description template. One
example:

  style/period = "Late Georgian"
  =>
  culture = "British" AND
  date.created = 1760, 1811

[Style/period, culture and date.created are all VRA data elements
defined as slots for our art-object description template.]

We could not define this constraint in RDFS and (a little to our
surprise)
we saw no way of expressing it in DAML+OIL either (we could have
misread the spec, we would be glad to be proven wrong). 

This type of semantical information is essential to show added value
of semantic annotations.

WEBONT REQUIREMENTS
possibility to define inter-slot constraints of a class



[1] The Art and Architecture Thesaurus
    http://shiva.pub.getty.edu.

[2] Visual Resources Association~Standards Committee.
    VRA core categories, version 3.0.
    Technical report, Visual Resources Association, July 2000.
    http://www.gsd.harvard.edu/~staffaw3/vra/vracore3.htm.

-- 
A. Th. Schreiber, SWI, University of Amsterdam, Roetersstraat 15
NL-1018 WB Amsterdam, The Netherlands, Tel: +31 20 525 6793 
Fax: +31 20 525 6896; E-mail: schreiber@swi.psy.uva.nl
WWW: http://www.swi.psy.uva.nl/usr/Schreiber/home.html
Received on Friday, 30 November 2001 09:43:36 GMT

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