1. A method for updating ontology when a set of evidences and a set of constraints are given as inputs, the method comprising: a computer categorizing one or more new concepts included in a set of evidences into one of three sets, a) a definitely relevant set, b) a possibly relevant set, and c) an irrelevant set; the computer adding a categorized new concept included in the definitely relevant set to an first ontology; the computer adding a categorized new concept included in the possibly relevant set to a residual ontology; the computer matching one or more new concepts included in the set of evidences to an old concept included in the first ontology or to an old concept included in the residual ontology, wherein an old concept existed as part of the first ontology or the residual ontology before the respective addition of the new concepts to the first ontology or the residual ontology; the computer determining to increase an associated confidence measure of the old concept, included in the first ontology or the residual ontology, based at least in part, on the matching; the computer determining to expand the first ontology or the residual ontology by respectively adding one or more new concepts to the first ontology or the residual ontology; and the computer removing one or more old concepts from the first ontology or the residual ontology based, at least in part, on a set of constraints, wherein the constraints dictate size and performance requirements of the first ontology.