If you have problems with all files, try some "(pdf)". If that does not work, install Adobe Reader (e.g., the free version) or some other pdf reader and try again.

Kalle M. Mikkola. SIAM J. Control Optim., 50(3), 1071–1086. (16 pages).

article (a preprint (pdf)) (corresponding report with some additional details: report A528 (pdf)).

**Bass and topological stable ranks of complex and real algebras of measures, functions and sequences**

Kalle M. Mikkola and Amol J. Sasane.
48 pp., Complex Analysis and Operator Theory, Volume 4, Number 2, 401-448, DOI: 10.1007/s11785-009-0009-1
html + pdf (errata)
(pdf)

**PID Controller Tuning Rules for Integrating Processes with Varying Time-Delays**

Lasse Eriksson, Timo Oksanen and Kalle Mikkola.
Journal of the Franklin Institute, 346 (5): pp. 470-487, 2009. (html etc.)

**Hankel and Toeplitz operators on nonseparable Hilbert spaces**

Kalle M. Mikkola.
Annales Academiae Scientiarum Fennicae Mathematica, 34: pp. 109-129, 2009.
html + pdf (see also the report with further results, details and explanations)

**Weakly coprime factorization and state-feedback stabilization of discrete-time systems**

Kalle M. Mikkola.
Mathematics of Control, Signals, and Systems, 20 (4), pp. 321-350, 2008.
article
(pdf)

**Fourier multipliers for L2 functions with values in nonseparable Hilbert spaces and operator-valued Hp boundary functions**

Kalle M. Mikkola.
Annales Academiae Scientiarum Fennicae Mathematica, 33: pp. 121-130, 2008.
html+pdf

**Weakly coprime factorization and continuous-time systems**

Kalle M. Mikkola.
IMA Journal of Mathematical Control and Information, 25 (4): pp. 515-546, 2008. doi:10.1093/imamci/dnn011
html+pdf pdf

**A spectrally minimal realization formula for H-infinity(D)
**

Kalle M. Mikkola and Amol J. Sasane.
Complex Analysis and Operator Theory, 1 (4), pp. 621-628, 2007. doi 10.1007/s11785-007-0021-2
html+pdf

**Tolokonnikov's Lemma for real H ^{∞ }
and the real disc algebra**

Kalle M. Mikkola and Amol J. Sasane. Complex Analysis and Operator Theory, 1 (3), pp. 439-446, 2007. html+pdf

**The Hilbert-Schmidt property of feedback operators**

Ruth F. Curtain, Kalle M. Mikkola and Amol J. Sasane.
Journal of Mathematical Analysis and Applications,
329 (2), pp. 1145-1160, 2007.
html+pdf
(pdf).

**Coprime factorization and dynamic stabilization of transfer functions**

Kalle M. Mikkola.
SIAM Journal on Control and Optimization, 45 (6), pp. 1988-2010, 2007.
pdf
(pdf)

**State-Feedback Stabilization of Well-Posed
Linear Systems**

Kalle M. Mikkola.
Integral Equations and Operator Theory
55 (2), pp. 249-271, 2006.
article
(pdf)
(ps)

**Characterization of Transfer Functions of
Pritchard–Salamon or Other Realizations with
a Bounded Input or Output Operator**

Kalle M. Mikkola.
Integral Equations and Operator Theory
54 (3), pp. 427-440, 2006.
article
(pdf)
(ps)

**State-Space Formulas for the Nehari--Takagi Problem for Nonexponentially Stable Infinite-Dimensional Systems**

Joseph A. Ball, Kalle M. Mikkola, Amol J. Sasane.
SIAM Journal on Control and Optimization
44 (2), pp. 531-563, 2005.
abstract and links
pdf
ps

Kalle M. Mikkola. Doctoral dissertation, 1059 pages; Technical Report A452, Institute of Mathematics, Helsinki University of Technology, 2002.

Kalle M. Mikkola and Ilya M. Spitkovsky, in Operator Algebras, Operator Theory and Applications, in Operator Theory: Advances and Applications, vol. 181, part 2, pp. 321-346. Eds: A. Bastos et. al., Birkhäuser, 2008.

**Optimal state feedback
and stabilizing compensators are real when data is real**

Kalle M. Mikkola.
Proceedings of the European Control Conference (ECC2007).

**The LQ-optimal control is weakly coprime**

Kalle M. Mikkola.
Proceedings of MTNS2006.

**Coprime factorizations and stabilization of infinite-dimensional linear systems**

Kalle M. Mikkola.
Proceedings of CDC-ECC2005. slides conference paper
(I recommend the slides, unless you want more details.)

**Coprime factorizations and stabilizability of infinite-dimensional linear systems**

Kalle M. Mikkola and Olof J. Staffans*.
Proceedings of MTNS2004 (CDROM).

**Riccati equations and optimal control for infinite-dimensional linear systems**

Kalle M. Mikkola and Olof J. Staffans*.
Proceedings of MTNS2004 (CDROM).

**A Riccati equation approach to the standard infinite-dimensional H-infinity problem**

Kalle M. Mikkola and Olof J. Staffans*.
Mathematical Theory of Networks and Systems (MTNS2002; CDROM).

*) The research on these articles was carried by me. Due to my obligations elsewhere the presentations at these conferences were delivered by Olof Staffans.

Kalle M. Mikkola. Research report A528. Helsinki University of Technology. Institute of Mathematics. Espoo, Finland, 2007. pdf

**Types of systems:**
Well-posed linear systems (Salamon-Weiss systems or abstract linear systems), regular linear systems and some other less and more general linear, mainly time-invariant systems, continuous-time or discrete-time.

**Introduction:**
Non-experts may read the
introduction to my thesis to get some idea on my main subject, infinite-dimensional systems and control theory.
Technically the proofs typically use functional analysis and algebra with some real and harmonic analysis and function theory (of vector- or operator-valued functions, usually on arbitrary Hilbert spaces).
A more general and
elementary introduction on control theory for laymen is given in Wikipedia.