In the context of this work the inductive system is used only as generator of rules. The system used for learning those rules was YAILS [12,13]. YAILS system belongs to the attribute-based family of learning programs. It is an incremental rule learning system capable of dealing with numerical attributes and noisy domains. It uses a kind of hill-climbing search strategy with different types of generalisation and specialisation operators. This bi-directional search is guided by an evaluation function which is described in section 3.3.