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.