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Bagging with Asymmetric Costs for Misclassified and Correctly Classified Examples

  • Ricardo Ñanculef
  • Carlos Valle
  • Héctor Allende
  • Claudio Moraga
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 4756)

Abstract

Diversity is a key characteristic to obtain advantages of combining predictors. In this paper, we propose a modification of bagging to explicitly trade off diversity and individual accuracy. The procedure consists in dividing the bootstrap replicates obtained at each iteration of the algorithm in two subsets: one consisting of the examples misclassified by the ensemble obtained at the previous iteration, and the other consisting of the examples correctly recognized. A high individual accuracy of a new classifier on the first subset increases diversity, measured as the value of the Q statistic between the new classifier and the existing classifier ensemble. A high accuracy on the second subset on the other hand, decreases diversity. We trade off between both components of the individual accuracy using a parameter λ ∈ [0,1] that changes the cost of a misclassification on the second subset. Experiments are provided using well-known classification problems obtained from UCI. Results are also compared with boosting and bagging.

Keywords

Ensemble Methods Bagging Diversity Neural Networks Classification Algorithms 

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Copyright information

© Springer-Verlag Berlin Heidelberg 2007

Authors and Affiliations

  • Ricardo Ñanculef
    • 1
  • Carlos Valle
    • 1
  • Héctor Allende
    • 1
  • Claudio Moraga
    • 2
    • 3
  1. 1.Universidad Técnica Federico Santa María, Departamento de Informática, CP 110-V ValparaísoChile
  2. 2.European Centre for Soft Computing 33600 Mieres, AsturiasSpain
  3. 3.Dortmund University, 44221 DortmundGermany

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