abstract = "This paper describes a technique on an optimisation of
tree-structure data, or genetic programming (GP), by
means of a multi-objective optimization technique.
NSGA-II is applied as a frame work of the
multi-objective optimization. GP induces bloat of the
tree structure as one of the major problem. The cause
of bloat is that the tree structure obtained by the
crossover operator grows bigger and bigger but its
evaluation does not improve. To avoid the risk of
bloat, a partial sampling (PS) operator is proposed
instead to the crossover operator. Repeating processes
of proliferation and metastasis in PS operator, new
tree structure is generated as a new individual.
Moreover, the size of the tree and a structural
distance (SD) are additionally introduced into the
measure of the tree-structure data as the objective
functions. And then, the optimization problem of the
tree-structure data is defined as a three-objective
optimization problem. SD is also applied to the
selection of parent individuals instead to the crowding
distance of the conventional NSGA-II. The effectiveness
of the proposed techniques is verified by applying to
the double spiral problem.",
notes = "Oct 2020 author name corrected before reported as
Makoto Ohri