Learning Classifier Systems

Volume 4399 of the series Lecture Notes in Computer Science pp 291-307

Improving the Performance of a Pittsburgh Learning Classifier System Using a Default Rule

  • Jaume BacarditAffiliated withASAP, School of Computer Science and IT, University of Nottingham, Jubilee Campus, Wollaton Road, Nottingham, NG8 1BB
  • , David E. GoldbergAffiliated withIllinois Genetic Algorithms Laboratory (IlliGAL), Department of General Engineering, University of Illinois at Urbana-Champaign, 104 S. Mathews Ave, Urbana, IL 61801
  • , Martin V. ButzAffiliated withDepartment of Cognitive Psychology, University of Würzburg, 97070 Würzburg

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An interesting feature of encoding the individuals of a Pittsburgh learning classifier system as a decision list is the emergent generation of a default rule. However, performance of the system is strongly tied to the learning system choosing the correct class for this default rule. In this paper we experimentally study the use of an explicit (static) default rule. We first test simple policies for setting the class of the default rule, such as the majority/minority class of the problem. Next, we introduce some techniques to automatically determine the most suitable class.