Extracting rules from multilayer perceptrons in classification problems: A clustering-based approach

Multilayer perceptrons adjust their internal parameters performing vector mappings from the input to the output space. Although they may achieve high classification accuracy, the knowledge acquired by such neural networks is usually incomprehensible for humans. This fact is a major obstacle in data mining applications, in which ultimately understandable patterns (like classification rules) are very important. Therefore, many algorithms for rule extraction from neural networks have been developed. This work presents a method to extract rules from multilayer perceptrons trained in classification problems. The rule extraction algorithm basically consists of two steps. First, a clustering genetic algorithm is applied to find clusters of hidden unit activation values. Then, classification rules describing these clusters, in relation to the inputs, are generated. The proposed approach is experimentally evaluated in four datasets that are benchmarks for data mining applications and in a real-world meteorological dataset, leading to interesting results.