Efficient coverage of case space with active learning

Abstract

Collecting and annotating exemplary cases is a costly and critical task that is required in early stages of any classification process. Reducing labeling cost without degrading accuracy calls for a compromise solution which may be achieved with active learning. Common active learning approaches focus on accuracy and assume the availability of a pre-labeled set of exemplary cases covering all classes to learn. This assumption does not necessarily hold. In this paper we study the capabilities of a new active learning approach, d-Confidence, in rapidly covering the case space when compared to the traditional active learning confidence criterion, when the representativeness assumption is not met. Experimental results also show that d-Confidence reduces the number of queries required to achieve complete class coverage and tends to improve or maintain classification error. © 2009 Springer Berlin Heidelberg.