“…The adjective "cross" here indicates that MSE-like terms are product terms extending over the baseline finite element model (FEM) of the healthy structure and the measured damaged structure, also extending over various modes. The CMSE is defined as C * m,n = (φ i ) T K n φ * j i = 1, 2, · · · , N i , j = 1, 2, · · · , N j (5) where φ i and K n are the i-th analytical mode shape and the n-th stiffness submatrix of the baseline FEM, respectively, and N i is the number of analytical modes. In practice, it is easy to obtain the analytical modes of the baseline FEM, but difficult or expensive to extract the measured modes of the damaged structure [10]; therefore, one may select a much larger N i than N j , i.e., N i N j .…”