OFFD: Optimal Flexible Frequency Discretization for Naïve Bayes Classification

Song Wang, Fan Min, Zhihai Wang, Tianyu Cao

Abstract: Incremental Flexible Frequency Discretization (IFFD) is a recently proposed discretization approach for Naïve Bayes (NB). IFFD performs satisfactory by setting the minimal interval frequency for discretized intervals as a fixed number. In this paper, we first argue that this setting cannot guarantee optimal classification performance in terms of classification error. We observed empirically that an optimal minimal interval frequency existed for each dataset. We thus proposed a sequential search and wrapper based incremental discretization method for NB: named Optimal Flexible Frequency Discretization (OFFD). Experiments were conducted on 17 datasets from UCI machine learning repository and performance was compared between NB trained on the data discretized by OFFD, IFFD, PKID, and FFD respectively. Results show that OFFD works better than these alternatives for NB. Experiments between NB discretized on the data with OFFD and C4.5 showed that our new method outperforms C4.5 on most of the datasets we have tested.