Kalle Mikkola (up)

Publications

Please, contact me if you have problems in getting the articles listed below. I use the following abbreviations:
  • article = often opens the abstract with a link to the complete article
  • pdf = PDF file of the article (use, e.g., Adobe Reader)
  • ps = PostScript file of the article (use, e.g., GhostView)
  • (pdf) or (ps) = as above but an inofficial version (page numbers and some typographic details may differ; contents and theorem numbers should be the same). These are available for everyone; the official versions (without parentheses) often only for the subscribers of the corresponding journals.

    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.

    Refereed articles in international journals

    Real solutions to control, approximation and factorization problems
    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

    Monograph

    Infinite-Dimensional Linear Systems, Optimal Control and Algebraic Riccati Equations
    Kalle M. Mikkola. Doctoral dissertation, 1059 pages; Technical Report A452, Institute of Mathematics, Helsinki University of Technology, 2002.

    Chapters in books

    Spectral factorization, unstable canonical factorization, and open factorization problems in control theory
    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.

    Selected refereed international conference articles

    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.

    Selected reports (not refereed)

    Hankel and Toeplitz operators on nonseparable Hilbert spaces: further results
    Kalle M. Mikkola. Research report A528. Helsinki University of Technology. Institute of Mathematics. Espoo, Finland, 2007. pdf

    Other

    Newer submitted articles, technical reports and non-refereed conference presentations are available at request.

    Research

    The main focus of my research is in the system and control theory of infinite-dimensional systems, particularly well-posedness, regularity, (state-feedback or output-feedback) stabilization, optimization (also indefinite, e.g., the H-infinity problem), Riccati equations and [weakly] coprime factorizations, but also some related subjects and more general analysis are covered. I am very interested in joint work, where my expertize can be utilized.

    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.