TY - GEN
T1 - On the least-squares approximation of structured covariances
AU - Lin, Fu
AU - Jovanović, Mihailo R.
PY - 2007/12/1
Y1 - 2007/12/1
N2 - State covariances of the linear systems satisfy certain constraints imposed by the underlying dynamics. These constraints dictate a particular structure of state covariances. On the other hand, sample covariances (e.g., obtained in experiments) almost always fail to have the required structure. In view of this, it is of interest to approximate sample covariances by positive semi-definite matrices of the required structure. The structured covariance least-squares approximation problem is formulated and the Lyapunov-type matrical linear constraint is converted into an equivalent set of trace constraints. Efficient quasi Newton and generalized Newton methods capable of solving the corresponding unconstrained dual problems with the large number of variables are developed.
AB - State covariances of the linear systems satisfy certain constraints imposed by the underlying dynamics. These constraints dictate a particular structure of state covariances. On the other hand, sample covariances (e.g., obtained in experiments) almost always fail to have the required structure. In view of this, it is of interest to approximate sample covariances by positive semi-definite matrices of the required structure. The structured covariance least-squares approximation problem is formulated and the Lyapunov-type matrical linear constraint is converted into an equivalent set of trace constraints. Efficient quasi Newton and generalized Newton methods capable of solving the corresponding unconstrained dual problems with the large number of variables are developed.
KW - Convex optimization
KW - Least-squares approximation
KW - Sample covariances
UR - http://www.scopus.com/inward/record.url?scp=46449125030&partnerID=8YFLogxK
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U2 - 10.1109/ACC.2007.4283143
DO - 10.1109/ACC.2007.4283143
M3 - Conference contribution
AN - SCOPUS:46449125030
SN - 1424409888
SN - 9781424409884
T3 - Proceedings of the American Control Conference
SP - 2648
EP - 2653
BT - Proceedings of the 2007 American Control Conference, ACC
T2 - 2007 American Control Conference, ACC
Y2 - 9 July 2007 through 13 July 2007
ER -