been designed to reduce the order or to reorder the system
equations to achieve better computational efficiency while
maintaining accuracy. The works of Shiau and Hwang
(1989) and of Nelson and Chen (1993) are particularly
noteworthy. Their work proposed a modeling procedure
using assumed modes to reduce the order of the system
matrices. Childs and Graviss (1982) and Chen (1998) used
different reordering techniques to increase computational
efficiency.