Operator equalisation, bloat and overfitting: a study on human oral bioavailability prediction

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32 Citations (Scopus)


Operator equalisation was recently proposed as a new bloat control technique for genetic programming. By controlling the distribution of program lengths inside the population, it can bias the search towards smaller or larger programs. In this paper we propose a new implementation of operator equalisation and compare it to a previous version, using a hard real-world regression problem where bloat and overfitting are major issues. The results show that both implementations of operator equalisation are completely bloat-free, producing smaller individuals than standard genetic programming, without compromising the generalization ability. We also show that the new implementation of operator equalisation is more efficient and exhibits a more predictable and reliable behavior than the previous version. We advance some arguable ideas regarding the relationship between bloat and overfitting, and support them with our results.
Original languageUnknown
Title of host publicationProceedings of the 11th Annual conference on Genetic and evolutionary computation
EditorsRaidl Gea(
PublisherACM - Association for Computing Machinery
Publication statusPublished - 1 Jan 2009
EventGECCO ’09 -
Duration: 1 Jan 2009 → …


ConferenceGECCO ’09
Period1/01/09 → …

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