“…The fitness function covers six objectives: the overlapping of the reading areas, the number of useless readers, the number of redundant readers, the number of tags located in the overlap reading areas, the number of uncovered tags and the deployment cost. Note that, in the last objective, we take the deployment cost in [10] to replace "the number of readers located out of the deployment area" in [14] (because it is practically unreasonable to deploy readers out of a pre-specified deployment area). Like [10], we also define each objective as f i = 1/(100+|ε i |) in order to remove possible biased effects due to a certain objective, i.e., to be more practical and reasonable.…”