Radial Basis Function (RBF) networks typically use a distance function designed for numeric
attributes, such as Euclidean or city-block distance. This paper presents a heterogeneous distance
function which is appropriate for applications with symbolic attributes, numeric attributes, or both.
Empirical results on 30 data sets indicate that the heterogeneous distance metric yields significantly
improved generalization accuracy over Euclidean distance in most cases involving symbolic attributes.