“…Much research interest has been directed recently to system identification (SI) of civil, mechanical, and aerospace structures in response to the increasing need of enhancement of safety and upgrade of ability of damage detection (or damage diagnosis) of various kinds of structures (Hart and Yao, 1977;Beck and Jennings, 1980;Hoshiya and Saito, 1984;Kozin and Natke, 1986;Agbabian et al, 1991;Koh et al, 1991;Ghanem and Shinozuka, 1995;Hjelmstad et al, 1995;Shinozuka and Ghanem, 1995;Doebling et al, 1996;Hjelmstad, 1996;Masri et al, 1996;Housner et al, 1997;Kobori et al, 1998;Johnson and Smyth, 2006;Nagarajaiah and Basu, 2009;Fujino et al, 2010;Ji et al, 2011). Such need results from the accelerated demand of rapid assessment on material aging issues and of continuing use of buildings after earthquakes.…”