Concluding remarks 237established so that the problem structure is developed. Immediately, an
information audit is possible considering what is known about the content
of the interaction matrix boxes.
If the state variables are conceptual in nature, the off-diagonal inter-
actions can be assessed using a semi-quantitative method of coding
(Hudson, 1992). By summing the coding values in the matrix rows and
columns, an estimate of each variable’s interactive intensity and dominance
in the system can be determined. This is known as the soft systems
approach.
If the state variables are physical variables, a new modelling technique
known as the fully-coupled model can be used (Hudson and Jiao, 1996).
The physical mechanisms linking the variables are identified for each off-
diagonal box and the relation quantified. A coupling algorithm is invoked
to produce a new interaction matrix in which all the terms represent a fully-
coupled system response; in other words, the response for all mechanisms
operating simultaneously. The new matrix allows quantitative prediction
of the effect of any applied perturbation on the state variables, whether
natural or by engineering. This is known as the hard systems approach.