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



1993

417.

Maten, E. J. W.; Huijben, A. J. M.
Vector extrapolation applied to a time cyclic heat problem
In Lewis, R. W., Editor, Numerical methods in thermal problemsBand8(2), Seite 983-994
In Lewis, R. W., Editor
Herausgeber: Pineridge Press Lmt, Swansea, UK
1993

416.

Barclay, V. J.; Hamilton, I. P.; Jensen, Per
Vibrational levels for the lowest-lying triplet and singlet states of CH\(_{2}\) and NH\(_{2}\)\(^{+}\)
The Journal of Chemical Physics, 99 (12) :9709-9719
1993

415.

Barclay, V. J.; Hamilton, I. P.; Jensen, Per
Vibrational levels for the lowest-lying triplet and singlet states of CH\(_{2}\) and NH\(_{2}\)\(^{+}\)
The Journal of Chemical Physics, 99 (12) :9709-9719
1993

414.

Barclay, V. J.; Hamilton, I. P.; Jensen, Per
Vibrational levels for the lowest-lying triplet and singlet states of CH2 and NH2+
The Journal of Chemical Physics, 99 (12) :9709-9719
1993
1992

413.

Kraemer, Wolfgang P.; Jensen, Per; Roos, B. O.; Bunker, Philip R.
Ab initio rotation-vibration energies and intensities for the HNC\(^{+}\) molecule
Journal of Molecular Spectroscopy, 153 (1-2) :240-254
1992

412.

Kraemer, Wolfgang P.; Jensen, Per; Roos, B. O.; Bunker, Philip R.
Ab initio rotation-vibration energies and intensities for the HNC\(^{+}\) molecule
Journal of Molecular Spectroscopy, 153 (1-2) :240-254
1992

411.

Kraemer, Wolfgang P.; Jensen, Per; Roos, B. O.; Bunker, Philip R.
Ab initio rotation-vibration energies and intensities for the HNC+ molecule
Journal of Molecular Spectroscopy, 153 (1-2) :240-254
1992

410.

Jensen, Per; Bunker, Philip R.; Epa, V. C.; Karpfen, Alfred
An ab initio calculation of the fundamental and overtone HCl stretching vibrations for the HCl dimer
Journal of Molecular Spectroscopy, 151 (2) :384-395
1992

409.

Jensen, Per; Bunker, Philip R.; Epa, V. C.; Karpfen, Alfred
An ab initio calculation of the fundamental and overtone HCl stretching vibrations for the HCl dimer
Journal of Molecular Spectroscopy, 151 (2) :384-395
1992

408.

Jensen, Per; Bunker, Philip R.; Epa, V. C.; Karpfen, Alfred
An ab initio calculation of the fundamental and overtone HCl stretching vibrations for the HCl dimer
Journal of Molecular Spectroscopy, 151 (2) :384-395
1992

407.

Jensen, Per; Rohlfing, Celeste Michael; Alml{ö}f, Jan
Calculation of the complete-active-space self-consistent-field potential-energy surface, the dipole moment surfaces, the rotation-vibration energies, and the vibrational transition moments for C\(_{3}\)(X\verb=~= \(^{1}\)\(\Sigma\)\(_{g}\)\(^{+}\))
The Journal of Chemical Physics, 97 (5) :3399-3411
1992

406.

Jensen, Per; Rohlfing, Celeste Michael; Alml{ö}f, Jan
Calculation of the complete-active-space self-consistent-field potential-energy surface, the dipole moment surfaces, the rotation-vibration energies, and the vibrational transition moments for C\(_{3}\)(X\verb=~= \(^{1}\)\(\Sigma\)\(_{g}\)\(^{+}\))
The Journal of Chemical Physics, 97 (5) :3399-3411
1992

405.

Jensen, Per; Rohlfing, Celeste Michael; Almlöf, Jan
Calculation of the complete-active-space self-consistent-field potential-energy surface, the dipole moment surfaces, the rotation-vibration energies, and the vibrational transition moments for C3(X~ 1Σg+)
The Journal of Chemical Physics, 97 (5) :3399-3411
1992

404.

Wildt, J{ü}rgen; Fink, Ewald H.; Biggs, P.; Wayne, Richard P.; Vilesov, A. F.
Collision-induced emission of O\(_{2}\)(a \(^{1}\)\(\Delta\)\(_{g}\) → X \(^{3}\)\(\Sigma\)\(_{g}\)\(^{-}\)) in the gas phase
Chemical Physics, 159 (1) :127-140
1992

403.

Wildt, J{ü}rgen; Fink, Ewald H.; Biggs, P.; Wayne, Richard P.; Vilesov, A. F.
Collision-induced emission of O\(_{2}\)(a \(^{1}\)\(\Delta\)\(_{g}\) → X \(^{3}\)\(\Sigma\)\(_{g}\)\(^{-}\)) in the gas phase
Chemical Physics, 159 (1) :127-140
1992

402.

Wildt, Jürgen; Fink, Ewald H.; Biggs, P.; Wayne, Richard P.; Vilesov, A. F.
Collision-induced emission of O2(a 1Δg → X 3Σg-) in the gas phase
Chemical Physics, 159 (1) :127-140
1992

401.

Heilmann, Margareta
Erhöhung der Konvergenzgeschwindigkeit bei der Approximation von Funktionen mit Hilfe von Linearkombinationen spezieller positiver linearer Operatoren
Universität Dortmund
1992

400.

Tausch, Michael W.
Erzeugung und Desaktivierung von angeregten Zuständen
Mitteilungsblatt der FG Chemieunterricht der GDCh (17) :253
1992

399.

Becker, Karl Heinz; Kurtenbach, Ralf; Wiesen, Peter
Investigation of N\(_{2}\)O formation in the NCO+NO reaction by Fourier-transform infrared spectroscopy
Chemical Physics Letters, 198 (3-4) :424-428
1992

398.

Becker, Karl Heinz; Kurtenbach, Ralf; Wiesen, Peter
Investigation of N\(_{2}\)O formation in the NCO+NO reaction by Fourier-transform infrared spectroscopy
Chemical Physics Letters, 198 (3-4) :424-428
1992

397.

Becker, Karl Heinz; Kurtenbach, Ralf; Wiesen, Peter
Investigation of N2O formation in the NCO+NO reaction by Fourier-transform infrared spectroscopy
Chemical Physics Letters, 198 (3-4) :424-428
1992

396.

Becker, Karl Heinz; K{ö}nig, R.; Meuser, R.; Wiesen, Peter; Bayes, Kyle D.
Kinetics of C\(_{2}\)O radicals formed in the photolysis of carbon suboxide at 308 and 248 nm
Journal of Photochemistry and Photobiology, A: Chemistry, 64 (1) :1-14
1992

395.

Becker, Karl Heinz; K{ö}nig, R.; Meuser, R.; Wiesen, Peter; Bayes, Kyle D.
Kinetics of C\(_{2}\)O radicals formed in the photolysis of carbon suboxide at 308 and 248 nm
Journal of Photochemistry and Photobiology, A: Chemistry, 64 (1) :1-14
1992

394.

Becker, Karl Heinz; König, R.; Meuser, R.; Wiesen, Peter; Bayes, Kyle D.
Kinetics of C2O radicals formed in the photolysis of carbon suboxide at 308 and 248 nm
Journal of Photochemistry and Photobiology, A: Chemistry, 64 (1) :1-14
1992

393.

Tausch, Michael W.; Wachtendonk, M.; Deissenberger, H.; Porth, H.-R.; Weißenhorn, R.G.
Lehrerband mit didaktischen Hinweisen und Lösungen der Aufgaben zu STOFF-FORMEL-UMWELT, BAND 2: ORGANISCHE CHEMIE - ANGEWANDTE CHEMIE, Lehrbuch für die S II, (Grund- und Leistungskurse)
Herausgeber: C. C. Buchner, Bamberg
1992