Basic Idea of Algorithm OSHAM
1. While concept C is splittable, find a new sub-concept that corresponds
to the hypothesis that minimizes q(C) among h hypotheses generated by
(a) Finding a “good” feature concerning the best cover of C.
(b) Finding a closed feature subset S containing this feature.
(c) Forming a sub-concept with the intent S.
(d) Evaluate the quality function with new hypothesized sub-concept.
Find intersection of the new formed concept with existing concepts.
2. Of one of the following conditions holds then C is unsplittable
(a) There exist not any closed proper subset of features.
(b) The set of unclassified instances of C is too small.
(c) The set of unclassified instances of C is homogeneous enough.