On the energy of (0, 1)-matrices

The energy of a matrix is the sum of its singular values. We study the energy of (0, 1)-matrices and present two methods for constructing balanced incomplete block designs whose incidence matrices have the maximum possible energy amongst the family of all (0, 1)-matrices of given order and total number of ones. We also find a new upper bound for the energy of (p, q)-bipartite graphs.