en Optimal design Optimal design پژوهشي Research Evolution Strategies (ES) are a class of Evolutionary Algorithms based on Gaussian mutation and deterministic selection. Gaussian mutation captures pair-wise dependencies between the variables through a covariance matrix. Covariance Matrix Adaptation (CMA) is a method to update this covariance matrix. In this paper, the CMA-ES, which has found many applications in solving continuous optimization problems, is employed for size optimization of steel space trusses. Design examples reveal competitive performance of the algorithm compared to the other advanced metaheuristics. The covariance matrix adaptation evolution strategy; metaheuristics; space truss structures; size optimization 233 256 http://ijoce.iust.ac.ir/browse.php?a_code=A-10-1-14&slc_lang=en&sid=1 A. Kaveh 1800319475328460061 1800319475328460061 Yes M. Kalateh-Ahani 1800319475328460062 1800319475328460062 No M.S. Masoudi 1800319475328460063 1800319475328460063 No