RE: pun in ontolingua KB

Tim Lethbridge <>
From: Tim Lethbridge <>
Message-id: <199406212043.QAA18513@mail.csi.UOttawa.CA>
Subject: RE: pun in ontolingua KB
To: gruber@HPP.Stanford.EDU
Date: Tue, 21 Jun 94 16:40:42 EDT
In-reply-to: <XLView.772225353.7590.gruber@hpp-ssc-1>; from "Tom Gruber" at Jun 21, 94 11:38 am
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> At  8:26 AM 6/21/94 -0500, Benjamin J. Kuipers wrote:
> >Doug [Lenat] is right.  This is a (the?) critical issue in knowledge-sharing.

I agree wholehaeartedly. Dealing with this issue was one of the major themes
of my recently-submitted PhD thesis.

The approach I developed in CODE4 can be summarised as follows:

* Have separate concepts (frames, units etc.) for 1) things (length, car, etc.) and
  2) for the *terms* that are used in natural language when manipulating these
  concepts. A term can map to several user concepts, and several user concepts
  can be represented by several terms.

* When users are specifying knowledge they can either: 1) make *direct* links between
  concepts, or 2) specify a term and have the system point out
  when the term is ambiguous.

I prefer this scheme to relying on 'context' for several reasons:

1. Forcing a unique namespace even within a context is too restrictive. For
   example, the knowledge enterer may very well want to have two concepts
   represented by the term 'length' within a very narrow context.

2. Contexts overlap. It can be hard to remember which context is active
   and it can be complicated to constantly specify context in
   an interdisciplinary knowledge base.

 - Tim

Timothy C. Lethbridge   
H(voice/fax): 237-6642
W: (613) 564-8155                FAX: (613) 564-9486
Department of Computer Science, University of Ottawa
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