APPLICATION OF THE C4.5 CLASSIFIER TO BUILDING AN EXPERT-SYSTEM FOR ION CHROMATOGRAPHY

A classifier based on the philosophy of induction is used to create ru les for the choice of a detector for ion chromatography (IC). A data b ase of over 4000 instances was used to obtain suitable classifications , that were initially compiled for use in Haddad and Jackson's recent monograph on IC. The properties of an ion chromatography method that w ere used for rule building were solute name, separation mechanism, app lication, number of solutes, ion class, halide type, sulphate presence , nitrate presence, and whether a suppressor or post column detection was used. The classifier, C4.5, chooses the property that maximises th e amount of information gained. By examining properties that relate to a given class, C4.5 operates a top-down induction process. A tree wit h 62 rules was derived from this data base. The evaluation of these ru les against two test sets showed that 70% of the proposed methods were an exact match with the published methods and a further 22% gave prac tical methods as assessed by our expert.