JNCC 2 user manual and tutorial ( ver 0 . 9 )

This paper introduces JNCC2, the Java implementation of the Naive Credal Classifier2 (NCC2). JNCC2 is open source; it is hence freely available together with manual, sources and javadoc documentation. JNCC2 implements the Naive Credal Classifier2 (NCC2), i.e., an extension of Naive Bayes Classifier (NBC) towards imprecise probabilities. NCC2 is designed to return robust classification, even on small and/or incomplete data sets. A peculiar feature of NCC2 is that it returns imprecise classifications (i.e., more than one class) when faced with doubtful instances. The empirical results of Corani and Zaffalon (2007) have shown that NCC2 returns imprecise judgments on instances whose classification is truly doubtful; in fact, NBC achieves a much higher classification accuracy on the instances precisely classified by NCC2, than on those imprecisely classified by NCC2.