“…The weighted model reduction problem is tackled most often using variants of frequency-weighted balanced truncation; see Varga and Anderson [2003], Anderson and Liu [2002], Schelfhout and De Moor [2002], Gugercin and Antoulas [2004], Enns [1984], Wang et al [2002], Lin and Chiu [1992], Wang et al [1999], Sreeram and Ghafoor [2005] and references therein. For approaches that seek to minimize a weighted-H 2 error, see Halevi [1992] and Spanos et al [1992].…”