abstract = "This study focuses on mutation in Grammatical
Evolution and divides mutation events into those that
are structural in nature and those that are nodal. A
structural event being one that alters the length of
the phenotype. A nodal event simply alters the value at
any node of a derivation tree. We analyse and compare
the effect of integer, nodal and structural mutations
on fitness for randomly generated individuals before
continuing this analysis to their relative
problem-solving performance over full runs. The study
highlights the importance of understanding how the
search operators of an evolutionary algorithm behave.
The result in this case being a form of mutation for
Grammatical Evolution, node mutation, with a better
property of locality than standard integer-based
mutation, which does not discriminate between
structural and nodal contexts.",
notes = "GECCO-2009 A joint meeting of the eighteenth
international conference on genetic algorithms
(ICGA-2009) and the fourteenth annual genetic
programming conference (GP-2009).