  We consider the optimization problem of constructing a binary orthogonal
array (OA) starting from a bigger one, by removing a specified amount of lines.
In particular, we develop a genetic algorithm (GA) where the underlying
chromosomes are constant-weight binary strings that specify the lines to be
cancelled from the starting OA. Such chromosomes are then evolved through
balanced crossover and mutation operators to preserve the number of ones in
them. The fitness function evaluates the matrices obtained from these
chromosomes by measuring their distance from satisfying the constraints of an
OA smaller than the starting one. We perform a preliminary experimental
validation of the proposed genetic algorithm by crafting the initial OA as a
random permutation of several blocks of the basic parity-check array, thereby
guaranteeing the existence of an optimal solution.
