architecture originally proposed for Smalltalk. The system design model plays the role of MVC models, the models created from user views become MVC views and the compatibility relation between the system model and user views becomes the 00 model of MVC controls.
As an example we consider the construction of a teleconferencing system. The system should allow many users to communicate across a computer network using many different media. Users can establish many discussion groups. A particular user can participate in many groups in the same time.
The scheme of the system model created by the independent designer is presented on the Fig. 2. The vocabulary used there is the vocabulary of the system analyst and the diagram represents his view of the system. The user view of the system is presented on the Fig. 3. It shows the different perspective of the system created on the base of simple metaphors: conference room, conference table with a spatial order of participants (chairs) etc.
COOAD is an attempt toward unified method of the system development process based on 00 notation. It is not quite matured at the moment. However, it was included into a course delivered to software engineering students and applied to some practical cases realised as student projects. Interesting observation was that designers tried to take different user perspectives during construction of user views. Limitation of the method is assumption of 'a static user' - the natural process of development of the user from 'novice' to 'expert' is ignored at present.
Barfield L. The User Interface Concepts & Design. Addison-Wesley 1993.
Galitz W.O. Essential Guide to User Interface Design. Wiley Comp. Pub. 1996.
Hackos J., Redish J. User and Task Analysis for Interface Design, Wiley Comp. Pub. 1998.
Draft International Standard ISO DIS 9241-11 Ergonomic requirements for office work with visual display terminals (VDTs):- Part 11 Guidance on Usability.
Newman W., Lamming M. Interactive System Design. Addison-Wesley 1995.
Rumbaugh J.,et al The Unified Modeling Language Reference Manual, Addison Wesley, 1999