We now have two classes that have different behaviour but share common code. This achieves another element of virtue, the re-use of software. Finally OOP offers a method for standardising interfaces that can make objects interchangeable at run time. This is called Polymorphism , and as its name suggests allows objects of disparate type to be treated similarly. If applied strictly by limiting methods and parameters to some pre-determined set we may have interchangeable objects that all perform the same function but by radically different methods.
Polymorphism is achieved through inheritance.
Objects that inherit from other objects can be treated as if they are those parent objects for the purposes of reference. In this chapter an attempt has been made to review the literature associated with the work and to explain the underlying techniques and concepts used. Because the work covers several fields of knowledge the decision has been made to describe the techniques in more detail and at a more basic level than is customary for a thesis. While the function of Neural networks and Genetic Algorithms may be known to many, the sections on derivation of embedding parameters, local approximation and model parsimony contain information that is less widely known.