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Effect of constraints on evolving behavior trees for game AI


McClarron, P and Ollington, R and Lewis, I, Effect of constraints on evolving behavior trees for game AI, Proceedings of the 9th Annual International Conference on Computer Games Multimedia & Allied Technologies (CGAT 2016), 28-29 March 2016, Singapore, pp. 1-6. ISSN 2251-1679 (2016) [Refereed Conference Paper]

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DOI: doi:10.5176/2251-1679_CGAT16.2


Behavior trees are a popular method for creating AI characters in games. They allow modular and hierarchical behaviors, making it easy to maintain, extend and modify behaviors for differ situations. Nevertheless, a considerable amount of skill, experience and time is required to produce believable behaviors.

Previous attempts to automate the development of behavior trees using genetic programming have met with limited success. One of the reasons for this is that random crossover and mutation of a behavior tree can result in large trees with many nonsensical branches. We investigate different methods for constraining crossover and mutation of the behavior tree in order to reduce the size of the search space and improve the resultant AI.

Preliminary experiments have focused on the game Pacman and we present results showing that constraining crossover and mutation so that the resultant behavior trees always maintain a sensible structure produces significantly better results than an unconstrained algorithm.

Item Details

Item Type:Refereed Conference Paper
Keywords:genetic programming, behaviour trees, game AI
Research Division:Information and Computing Sciences
Research Group:Machine learning
Research Field:Neural networks
Objective Division:Information and Communication Services
Objective Group:Other information and communication services
Objective Field:Other information and communication services not elsewhere classified
UTAS Author:McClarron, P (Mr Paul McClarron)
UTAS Author:Ollington, R (Dr Robert Ollington)
UTAS Author:Lewis, I (Dr Ian Lewis)
ID Code:111701
Year Published:2016
Deposited By:Information and Communication Technology
Deposited On:2016-09-30
Last Modified:2018-05-10

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