JNCC2 is the Java implementation of the Naive Credal Classifier 2. NCC2 constitutes an extension of Naive Bayes towards imprecise probabilities; it is designed to return robust classification, even on small and/or incomplete data sets. A peculiar feature of NCC2 is that it returns set-valued (or imprecise) classifications (i.e., more than one class) when faced with doubtful instances. Imprecise classifications are valuable as they clearly highlight doubtful instances, preventing over-confident use of the issued judgments; however, they still convey an informative content, dropping unlikely classes. This could be appealing in contexts in which the classification outcome is especially sensitive, as for instance in medical area.

Extensive empirical investigation shows that NCC2 returns imprecise judgments on instances whose classification is truly doubtful; in fact, Naive Bayes achieves a much higher classification accuracy on the instances precisely classified by NCC2, than on those imprecisely classified by NCC2. We say that NCC2 isolates area of ignorance, i.e. subsets of instances over which the accuracy of Naive Bayes sharply drops.

JNCC2 is open source; it is released under the terms of the GNU GPL license; it is hence freely available together with manual, sources and javadoc documentation.

For more information, visit http://www.idsia.ch/~giorgio/jncc2.html