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Re: Need example of a River class being used as an individual ... anyone?

From: Steven Gollery <sgollery@cadrc.calpoly.edu>
Date: Mon, 10 Mar 2003 14:03:25 -0800
Message-ID: <3E6D0BAD.1050409@cadrc.calpoly.edu>
To: www-rdf-logic <www-rdf-logic@w3.org>


My inclination in this situation would be to make "RiversInSicily" a 
subClassOf "Rivers" with the restriction that the "inRegion" property is 
set to "Sicily". Are there circumstances where you would choose one 
approach over the other?

Steven Gollery

Enrico Franconi wrote:

>On 3/10/03 6:15 PM, Roger L. Costello wrote:
>> Can you think of a more compelling example?  /Roger
>Consider the class "Rivers" as having properties like "inRegion",
>"averageLenght", and "totalNumber". Each instance of this class is the group
>of rivers in a specific region; each instance would have specified the
>average length of the rivers in the group and their total number.
>So, for example, an instance of "Rivers" can be "RiversInSicily", having the
>property "inRegion" set to the value "Sicily", and specific numbers as
>values of the properties "averageLenght" and "totalNumber".
>"RiversInSicily" (which is an instance of the class "Rivers") can itself be
>seen as the class of all the rivers in Sicily; properties of this class can
>be the name of the river and its length. An instance of the class
>"RiversInSicily" could be the "SalsoRiver", with value "Salso" for the
>property "name" and value 150km for the property "length".
>Obviously you may want to write a constraint saying that the count of the
>rivers which are instances of "RiversInSicily" (seen as class) is equal to
>the value of the property  "totalNumber" of "RiversInSicily" (seen as
>instance), and that the average of the lenghts of the rivers which are
>instances of "RiversInSicily" (seen as class) is equal to the value of the
>property "averageLenght"  of "RiversInSicily" (seen as instance).
>This stuff goes back at least to the good old days of Telos (for its
>theoretical foundations):
>John Mylopoulos, Alexander Borgida, Matthias Jarke, Manolis Koubarakis:
>Telos: Representing Knowledge About Information Systems. TOIS 8 (4): 325-362
>and to KEE (for its practical successful implementation):
>The Role of Frame-Based Representation in Reasoning, R.Fikes et al, CACM
>28(9):904- 920 (Sept 1985).
>-- e.
>Enrico Franconi                  - franconi@inf.unibz.it
>Free University of Bozen-Bolzano - http://www.inf.unibz.it/~franconi/
>Faculty of Computer Science      - Phone: (+39) 0471-315-642
>I-39100 Bozen-Bolzano BZ, Italy  - Fax:   (+39) 0471-315-649
Received on Monday, 10 March 2003 18:40:21 UTC

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