Applied and Computational Mathematics (ACM)

Model Order Reduction

Model Order Reduction (MOR) is the art of reducing a system's complexity while preserving its input-output behavior as much as possible.

Processes in all fields of todays technological world, like physics, chemistry and electronics, but also in finance, are very often described by dynamical systems. With the help of these dynamical systems, computer simulations, i.e. virtual experiments, are carried out. In this way, new products can be designed without having to build costly prototyps.

Due to the demand of more and more realistic simulations, the dynamical systems, i.e., the mathematical models, have to reflect more and more details of the real world problem. By this, the models' dimensions are increasing and simulations can often be carried out at high computational cost only.

In the design process, however, results are needed quickly. In circuit design, e.g., structures may need to be changed or parameters may need to be altered, in order to satisfy design rules or meet the prescribed performance. One cannot afford idle time, waiting for long simulation runs to be ready.

Model Order Reduction allows to speed up simulations in cases where one is not interested in all details of a system but merely in its input-output behavior. That means, considering a system, one may ask:

  • How do varying parameters influence certain performances ?
    Using the example of circuit design: How do widths and lengths of transistor channels, e.g., influence the voltage gain of a circuit.
  • Is a system stable?
    Using the example of circuit design: In which frequency range, e.g., of voltage sources, does the circuit perform as expected
  • How do coupled subproblems interact?
    Using the example of circuit design: How are signals applied at input-terminals translated to output-pins?

Classical situations in circuit design, where one does not need to know internals of blocks are optimization of design parameters (widths, lengths, ...) and post layout simulations and full system verifications. In the latter two cases, systems of coupled models are considered. In post layout simulations one has to deal with artificial, parasitic circuits, describing wiring effects.

Model Order Reduction automatically captures the essential features of a structure, omitting information which are not decisive for the answer to the above questions. Model Order reduction replaces in this way a dynamical system with another dynamical system producing (almost) the same output, given the same input with less internal states.

MOR replaces high dimensional (e.g. millions of degrees of freedom) with low dimensional (e.g. a hundred of degrees of freedom ) problems, that are then used instead in the numerical simulation.

The working group "Applied Mathematics/Numerical Analysis" has gathered expertise in MOR, especially in circuit design. Within the EU-Marie Curie Initial Training Network COMSON, attention was concentrated on MOR for Differential Algebraic Equations. Members that have been working on MOR in the EU-Marie Curie Transfer of Knowledge project O-MOORE-NICE! gathered knowledge especially in the still immature field of MOR for nonlinear problems.

Current research topics include:

  • MOR for nonlinear, parameterized problems
  • structure preserving MOR
  • MOR for Differential Algebraic Equations
  • MOR in financial applications, i.e., option prizing

Group members working on that field

  • Jan ter Maten
  • Roland Pulch

Publications



1997

691.

Bludsky, Ota; Jensen, Per
The calculation of the bound and quasibound vibrational states for ozone in its \(^{1}\)B\(_{2}\) electronic state
Molecular Physics, 91 (4) :653-662
1997

690.

Bludsky, Ota; Jensen, Per
The calculation of the bound and quasibound vibrational states for ozone in its 1B2 electronic state
Molecular Physics, 91 (4) :653-662
1997

689.

Kozin, Igor N.; Jensen, Per
The Effects of Nonzero Total Electron Spin in the X\verb=~= \(^{3}\)B\(_{1}\) State of Methylene CH\(_{2}\)
Journal of Molecular Spectroscopy, 183 (2) :398-406
1997
Herausgeber: Academic Press

688.

Kozin, Igor N.; Jensen, Per
The Effects of Nonzero Total Electron Spin in the X\verb=~= \(^{3}\)B\(_{1}\) State of Methylene CH\(_{2}\)
Journal of Molecular Spectroscopy, 183 (2) :398-406
1997
Herausgeber: Academic Press

687.

Kozin, Igor N.; Jensen, Per
The Effects of Nonzero Total Electron Spin in the X~ 3B1 State of Methylene CH2
Journal of Molecular Spectroscopy, 183 (2) :398-406
1997
Herausgeber: Academic Press

686.

Klamroth, Kathrin; Mengersen, Ingrid
The Ramsey number r(K_1,3,C_4,K_4)
Utilitas Mathematica, 52 :65-81
1997

685.

Jensen, Per; Sauer, Stephan P. A.
Theoretical calculations of the hyperfine structure in the spectra of H\(_{3}\)\(^{+}\) and its deuterated isotopomers
Molecular Physics, 91 (2) :319-332
1997

684.

Jensen, Per; Sauer, Stephan P. A.
Theoretical calculations of the hyperfine structure in the spectra of H\(_{3}\)\(^{+}\) and its deuterated isotopomers
Molecular Physics, 91 (2) :319-332
1997

683.

Jensen, Per; Sauer, Stephan P. A.
Theoretical calculations of the hyperfine structure in the spectra of H3+ and its deuterated isotopomers
Molecular Physics, 91 (2) :319-332
1997

682.

Jensen, Per
Theoretical Rotation-Vibration Energies of X\verb=~=\(^{3}\)B\(_{1}\) NH\(_{2}\)\(^{+}\)
Journal of Molecular Spectroscopy, 181 (1) :207-214
1997
Herausgeber: Academic Press

681.

Jensen, Per
Theoretical Rotation-Vibration Energies of X\verb=~=\(^{3}\)B\(_{1}\) NH\(_{2}\)\(^{+}\)
Journal of Molecular Spectroscopy, 181 (1) :207-214
1997
Herausgeber: Academic Press

680.

Jensen, Per
Theoretical Rotation-Vibration Energies of X~3B1 NH2+
Journal of Molecular Spectroscopy, 181 (1) :207-214
1997
Herausgeber: Academic Press
1996

679.

Kukui, A.; Kirchner, Ulf; Benter, Thorsten; Schindler, Ralph N.
A Gaskinetic Investigation of HOBr Reactions with Cl(\(^{2}\)P), O(\(^{3}\)P) and OH(\(^{2}\)\(\Pi\)). The Reaction of BrCl with OH(\(^{2}\)\(\Pi\))
Berichte der Bunsengesellschaft für physikalische Chemie, 100 (4) :455-461
1996

678.

Kukui, A.; Kirchner, Ulf; Benter, Thorsten; Schindler, Ralph N.
A Gaskinetic Investigation of HOBr Reactions with Cl(\(^{2}\)P), O(\(^{3}\)P) and OH(\(^{2}\)\(\Pi\)). The Reaction of BrCl with OH(\(^{2}\)\(\Pi\))
Berichte der Bunsengesellschaft für physikalische Chemie, 100 (4) :455-461
1996

677.

Kukui, A.; Kirchner, Ulf; Benter, Thorsten; Schindler, Ralph N.
A Gaskinetic Investigation of HOBr Reactions with Cl(2P), O(3P) and OH(2Π). The Reaction of BrCl with OH(2Π)
Berichte der Bunsengesellschaft für physikalische Chemie, 100 (4) :455-461
1996

676.

Gu, Jian-ping; Buenker, Robert J.; Hirsch, Gerhard; Jensen, Per; Bunker, Philip R.
An ab Initio Calculation of BH\(_{2}\)\(^{-}\) Rovibronic Energies: A Very Small Singlet-Triplet Splitting
Journal of Molecular Spectroscopy, 178 (2) :172-183
1996
Herausgeber: Academic Press

675.

Gu, Jian-ping; Buenker, Robert J.; Hirsch, Gerhard; Jensen, Per; Bunker, Philip R.
An ab Initio Calculation of BH\(_{2}\)\(^{-}\) Rovibronic Energies: A Very Small Singlet-Triplet Splitting
Journal of Molecular Spectroscopy, 178 (2) :172-183
1996
Herausgeber: Academic Press

674.

Gu, Jian-ping; Buenker, Robert J.; Hirsch, Gerhard; Jensen, Per; Bunker, Philip R.
An ab Initio Calculation of BH2- Rovibronic Energies: A Very Small Singlet-Triplet Splitting
Journal of Molecular Spectroscopy, 178 (2) :172-183
1996
Herausgeber: Academic Press

673.

Kolbuszewski, M.; Bunker, Philip R.; Kraemer, Wolfgang P.; Osmann, Gerald; Jensen, Per
An ab initio calculation of the rovibronic energies of the BH\(_{2}\) molecule
Molecular Physics, 88 (1) :105-124
1996

672.

Kolbuszewski, M.; Bunker, Philip R.; Kraemer, Wolfgang P.; Osmann, Gerald; Jensen, Per
An ab initio calculation of the rovibronic energies of the BH\(_{2}\) molecule
Molecular Physics, 88 (1) :105-124
1996

671.

Kolbuszewski, M.; Bunker, Philip R.; Kraemer, Wolfgang P.; Osmann, Gerald; Jensen, Per
An ab initio calculation of the rovibronic energies of the BH2 molecule
Molecular Physics, 88 (1) :105-124
1996

670.

Jacob, Birgit
Destabilization of infinite-dimensional time-varying systems via dynamical output feedback
, Recent developments in operator theory and its applications (<prt>W</prt>innipeg, <prt>MB</prt>, 1994) Band 87 aus Oper. Theory Adv. Appl.
Seite 193--206
Herausgeber: Birkhäuser, Basel
1996
193--206

669.

Wiesen, Peter; Kleffmann, Jörg; Kurtenbach, Ralf; Becker, Karl Heinz
Emission of nitrous oxide and methane from aero engines: Monitoring by tunable diode laser spectroscopy
Infrared Physics and Technology, 37 (1) :75-81
1996
Herausgeber: Pergamon

668.

Wiesen, Peter; Kleffmann, Jörg; Kurtenbach, Ralf; Becker, Karl Heinz
Emission of nitrous oxide and methane from aero engines: Monitoring by tunable diode laser spectroscopy
Infrared Physics and Technology, 37 (1) :75-81
1996
Herausgeber: Pergamon

667.

Wiesen, Peter; Kleffmann, Jörg; Kurtenbach, Ralf; Becker, Karl Heinz
Emission of nitrous oxide and methane from aero engines: Monitoring by tunable diode laser spectroscopy
Infrared Physics and Technology, 37 (1) :75-81
1996
Herausgeber: Pergamon