Information Technology Reference
In-Depth Information
Target
system
interaction
Mental
models
Elicitation
procedures
introspection
Conceptual
models
Intermediate
knowledge
bases
Analysis
procedures
communication
Visual &
Functional
models of the
conceptual
models
Computer
knowledge
bases
CLARITY
Implimentation
procedures
formalization
Knowledge
representation
Cognitive
processes
Acquisition
procedures
Modeling
requirements
PSYCHOLOGICAL THEORIES
KNOWLEDGE ACQUISITION TOOLS
Fig. 4.3
Abstracting to a representation (The processes that link elicitation, modeling and formal
representation are shown (modified from Shaw and Woodward). The non-verbal representations
typically used in moving from conceptual models to formalized implementation ones are absent.)
diagrams are too informal to translate directly to a formal structure that can be im-
plemented as a program. For these, where the target system (implementation) forces
a representational bias, an extra stage in modelling is required.
Figure
4.3
shows the processes linking elicitation, modelling and formal rep-
resentation (modified from reference Shaw and Woodward
1990
). The non-verbal
representations typically used in moving from conceptual models to formalised,
implementable ones, are not shown.
It is well known to AI workers that sketches and diagrams are good guides to
implementation. Nevertheless, accounts assume that all diagrammatic modelling re-
duces to linguistic representation. Thus an account by Shaw and Woodward, in which
diagrammatic representations are not even identified as part of the process, shows
how quickly visualisations are replaced by linguistic representations. They therefore
underestimate the importance of diagrams to communication and conceptualisation
during the elicitation process (Fig.
4.3
). Of course, the machine representations
sought by knowledge engineers, like Maxwell's famous field equations, must be
symbolic in form. However, this fact does not require us to assume that all repre-
sentations reduce to linguistic ones. Images were just as important to Maxwell as
