2.9 CBR Processes 39
shown in Figure 2.8. This now more clearly shows that T is closer to B
than to A.
You can see how adding background knowledge to our nearest
neighbor formula in the form of relative importance or weightings on
each attribute dramatically altered which case was retrieved as a best
match.
Our example is very simple. In reality, cases may have ten,
twenty, or more attributes, each with its own weighting. Instead
of using a two-dimensional space, as in our example, cases are plot-
ted into a
N-dimensional space. Moreover, we are not restricted
to simple numerical comparisons of similarity. Some case features
may hold symbolic values (for ...