Qualitative data mining and its applications

In machine learning from numerical data, usually the target concept is a numerical function that facilitates quantitative prediction. In contrast to this, we consider qualitative data mining which aims at finding qualitative patterns, or qualitative relationships in numerical data. We present one approach to qualitative data mining, in which the target concepts are expressed as qualitative decision trees. We review some case studies in qualitative data mining, and discuss typical application scenarios that involve the learning of qualitative trees.