## The doctoral dissertations of the former Helsinki University of Technology (TKK) and Aalto University Schools of Technology (CHEM, ELEC, ENG, SCI) published in electronic format are available in the electronic publications archive of Aalto University - Aaltodoc. | |

Dissertation for the degree of Doctor of Science in Technology to be presented
with due permission of the Department of Engineering Physics and Mathematics,
for public examination and debate in Council Room at Helsinki University of
Technology (Espoo, Finland) on the
18^{th} of October, 2002, at 12 o'clock noon.

Dissertation in PDF format (ISBN 951-22-6079-4) [7482 KB]

Dissertation is also available in print (ISBN 951-22-6153-7)

In this monograph, we solve rather general linear, infinite-dimensional,
time-invariant control problems, including the
H^{∞} and LQR problems, in terms of algebraic
Riccati equations and of spectral or coprime factorizations. We work in the
class of (weakly regular) well-posed linear systems (WPLSs) in the sense of G.
Weiss and D. Salamon.

Moreover, we develop the required theories, also of independent interest, on WPLSs, time-invariant operators, transfer and boundary functions, factorizations and Riccati equations. Finally, we present the corresponding theories and results also for discrete-time systems.

**Keywords:**
suboptimal H-infinity control, standard H-infinity problem,
measurement feedback problem; H-infinity full information control problem,
state feedback problem; Nehari problem; LQC, LQR control, H2 problem,
minimization; bounded real lemma, positive real lemma; dynamic stabilization,
controller with internal loop, strong stabilization,
exponential stabilization, optimizability; canonical factorization,
(J,S)-spectral factorization, (J,S)-inner coprime factorization,
generalized factorization, J-lossless factorization; compatible operators,
weakly regular well-posed linear systems, distributed parameter systems;
continuous-time, discrete-time; infinite-horizon; time-invariant operators,
Toeplitz operators, Wiener class, equally-spaced delays, Popov function;
transfer functions, H-infinity boundary functions, Fourier multipliers;
Bochner integral, strongly measurable functions, strong Lp spaces;
Laplace transform, Fourier transform

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© 2002 Helsinki University of Technology

Last update 2011-05-26