Recursive Rule Extraction from NN using Reverse Engineering Technique

This paper proposes an algorithm named Reverse Engineering Recursive Rule Extraction (RE-Re-RX) for symbolic rule extraction from neural network with mixed attributes. RE-Re-RX algorithm is an extension of the existing Recursive Rule Extraction (Re-RX) algorithm. Re-RX algorithm generates disjoint rules for continuous and discrete attributes. The algorithm first generates rules for discrete attributes. A rule for discrete attributes is further refined recursively if it does not produce satisfactory result. A rule is refined by generating rules with the discrete attributes (if present) that are not covered by the rule or else the process is terminated by generating rules with the continuous attributes (if present). The novelty of the proposed RE-Re-RX algorithm lies in generating rules for continuous attributes. Re-RX generates linear hyper plane for continuous attributes which may not be able to deal with the non-linearity present in data. To overcome this limitation RE-Re-RX algorithm generates simple rules for continuous attributes in the form of input data ranges and target. RE-Re-RX uses the concept of Rule Extraction by Reverse Engineering the NN (RxREN) algorithm in slightly different way to generate rules. RxREN only uses misclassified patterns, whereas RE-Re-RX uses both classified and misclassified patterns of each continuous attribute to calculate input data ranges for constructing rules. The proposed algorithm is validated with six benchmark datasets. The experimental results clearly show the superiority of the proposed algorithm to Re-RX.