Abstract
Structured neural network system was developed for diagnosing hepatobillary diseases. Structure was given to the neural network by using the pre-existing medical knowledge before learning the neural network. Comparisons was made of diagnostic accuracy between the ordinary and structured neural networks. The error back propagation was used as the learning algorithm both neural networks. The diagnostic accuracy of the structured neural network was higher than that of the ordinary one. The structured neural network had some advantages over the ordinary network concerning rapidity and convergence of the learning. Structured neural network might be effective tools for acquiring the knowledge from the medical database.
