Hybrid toxicology expert system: architecture and implementation of a multi-domain hybrid expert system for toxicology

Ž . A hybrid expert system prototype using artificial neural networks ANN and classical rules has been developed for predicting toxicology of compounds. Modularity was a must for the architecture of the system. The study of chemicals was approached by establishing classes. When appropriate descriptors are calculated for the molecule, the ANN classifier assigns the chemical class to the compound. Then the toxic activity is quantitatively predicted of by one of the trained ANN in the Ž . system. After that, a qualitative prediction activernon-active is made by a rule-based system, calling only the correct Ž . knowledge base KB for the assigned class. This last step enabled us to give an explanation of the results. All the rules in the KBs have been obtained with automated learning techniques. q 1998 Elsevier Science B.V. All rights reserved.