Model accuracy in the Bayesian optimization algorithm

  • Authors:
  • Claudio F. Lima;Fernando G. Lobo;Martin Pelikan;David E. Goldberg

  • Affiliations:
  • University of Nottingham, Centre for Plant Integrative Biology, Sutton Bonington Campus, LE12 5RD, Loughborough, UK;University of Algarve, Department of Electronics and Informatics Engineering, Campus de Gambelas, 8000-117, Faro, Portugal;University of Missouri at St. Louis, Department of Mathematics and Computer Science, 320 CCB, 63121, St. Louis, MO, USA;University of Illinois at Urbana-Champaign, Department of Industrial and Enterprise Systems Engineering, 61801, Urbana, IL, USA

  • Venue:
  • Soft Computing - A Fusion of Foundations, Methodologies and Applications
  • Year:
  • 2011

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Abstract

Evolutionary algorithms (EAs) are particularly suited to solve problems for which there is not much information available. From this standpoint, estimation of distribution algorithms (EDAs), which guide the search by using probabilistic models of the population, have brought a new view to evolutionary computation. While solving a given problem with an EDA, the user has access to a set of models that reveal probabilistic dependencies between variables, an important source of information about the problem. However, as the complexity of the used models increases, the chance of overfitting and consequently reducing model interpretability, increases as well. This paper investigates the relationship between the probabilistic models learned by the Bayesian optimization algorithm (BOA) and the underlying problem structure. The purpose of the paper is threefold. First, model building in BOA is analyzed to understand how the problem structure is learned. Second, it is shown how the selection operator can lead to model overfitting in Bayesian EDAs. Third, the scoring metric that guides the search for an adequate model structure is modified to take into account the non-uniform distribution of the mating pool generated by tournament selection. Overall, this paper makes a contribution towards understanding and improving model accuracy in BOA, providing more interpretable models to assist efficiency enhancement techniques and human researchers.