id: 05570987 dt: a an: 05570987 au: Elwell, Ryan; Polikar, Robi ti: Incremental learning of variable rate concept drift. so: Benediktsson, Jón Atli (ed.) et al., Multiple classifier systems. 8th international workshop, MCS 2009, Reykjavik, Iceland, June 10‒12, 2009. Proceedings. Berlin: Springer (ISBN 978-3-642-02325-5/pbk). Lecture Notes in Computer Science 5519, 142-151 (2009). py: 2009 pu: Berlin: Springer la: EN cc: ut: nonstationary environment; concept drift; Learn$^{ + + }$.NSE ci: li: doi:10.1007/978-3-642-02326-2_15 ab: Summary: We have recently introduced an incremental learning algorithm, Learn$^{ + + }$.NSE, for Non-Stationary Environments, where the data distribution changes over time due to concept drift. Learn$^{ + + }$.NSE is an ensemble of classifiers approach, training a new classifier on each consecutive batch of data that become available, and combining them through an age-adjusted dynamic error based weighted majority voting. Prior work has shown the algorithm’s ability to track gradually changing environments as well as its ability to retain former knowledge in cases of cyclical or recurring data by retaining and appropriately weighting all classifiers generated thus far. In this contribution, we extend the analysis of the algorithm to more challenging environments experiencing varying drift rates; but more importantly we present preliminary results on the ability of the algorithm to accommodate addition or subtraction of classes over time. Furthermore, we also present comparative results of a variation of the algorithm that employs an error-based pruning in cyclical environments. rv: