[ont.events] ICR Feb.8 John Mylopoulos Telos:A Requirements Modelling Language

cfry@watdcsu.waterloo.edu (C.Fry - Inst. Computer Research) (02/03/89)

                            ICR presents a colloquium on


                      Telos: A Requirements Modelling Language


          by
          Dr. John Mylopoulos

          of
          Department of Computer Science
          University of Toronto


          Abstract

          It has been argued that the first step in the  development of  an
          information  system  should be the description of the environment
          within which the system is intended to function and of  the  role
          the  information  system  will play within that environment. This
          initial step of information system development is called require-
          ments  modelling.  We view requirements models as knowledge bases
          about  an  application  domain  and  propose  to  use   knowledge
          representation ideas to design a requirements modelling language.

          This talk describes the features, the formalization and an imple-
          mentation  of  a  language  called  Telos which is based on these
          ideas. Telos has evolved from earlier work by Sol Greenspan on  a
          language called RML and latter work by Alex Borgida, Martin Stan-
          ley, Manolis Koubarakis and others.

          Telos  supports  an  object-oriented  representational  framework
          which  encourages knowledge organization. Moreover, the framework
          treats attributes as objects in  their  own  right  and  provides
          means  for extending the language through the definition of meta-
          attributes. In addition, the framework offers  an  interval-based
          model  for  the  representation of time and distinguishes between
          the history of the domain and the history of the system's beliefs
          about  the  domain.  As with other representation systems, asser-
          tions can either serve as constraints on the knowledge base or as
          deductive  rules from which new facts can be derived. Interaction
          with the knowledge base is achieved through  ASKing  and  TELLing
          operations.


          DATE:       Wednesday, February 8, 1989
          TIME:       3:30 p.m.
          PLACE:      DC 1302
          Everyone is welcome.  Refreshments served.