Before revision:  Second, we introduce a spectral norm constraint to robustify the relaxed problem. Third, we use alternating direction method or the iteratively reweighted least squares (IRLS) procedureto solve the problem .
After revision:  Second, we introduce a spectral norm term that is added as a constraint or as a regularization term to the relaxed minimization problem. The resulted problems are solved by using either the alternating direction method or the iteratively reweighted least squares (IRLS) procedureto solve the problem .