“…This is the reason why spurious eigenvalues may appear in multiply-connected eigenproblems. In order to suppress the appearance of the spurious eigenvalues, three methods of extracting out true and spurious eigenvalues, including the CHIEF method (Chen et al, 2003), the SVD updating technique (Chen et al, 2003(Chen et al, , 2004b(Chen et al, , 2005(Chen et al, , 2007(Chen et al, , 2008b(Chen et al, , 2009a(Chen et al, , 2010a, and the Burton & Miller approach (Chen et al, 2001(Chen et al, , 2007) are adopted, respectively.…”