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



1983

67.

Jensen, Per
The nonrigid bender Hamiltonian for calculating the rotation-vibration energy levels of a triatomic molecule
Computer Physics Reports, 1 (1) :1-55
1983

66.

Jensen, Per
The nonrigid bender Hamiltonian for calculating the rotation-vibration energy levels of a triatomic molecule
Computer Physics Reports, 1 (1) :1-55
1983

65.

Holstein, K. J.; Fink, Ewald H.; Zabel, Friedhelm
The ν3 vibration of electronically excited HO2(A2A')
Journal of Molecular Spectroscopy, 99 (1) :231-234
1983
1982

64.

Winter, R.; Barnes, Ian; Fink, Ewald H.; Wildt, J{ü}rgen; Zabel, Friedhelm
b\(^{1}\)\(\Sigma\)\(^{+}\) and a\(^{1}\)\(\Delta\) emissions from group VI-VI diatomic molecules b0\(_{g}\)\(^{+}\) → X\(^{2}\)1\(_{g}\) emissions of Se\(_{2}\) and Te\(_{2}\)
Chemical Physics Letters, 86 (2) :118-122
1982

63.

Winter, R.; Barnes, Ian; Fink, Ewald H.; Wildt, J{ü}rgen; Zabel, Friedhelm
b\(^{1}\)\(\Sigma\)\(^{+}\) and a\(^{1}\)\(\Delta\) emissions from group VI-VI diatomic molecules b0\(_{g}\)\(^{+}\) → X\(^{2}\)1\(_{g}\) emissions of Se\(_{2}\) and Te\(_{2}\)
Chemical Physics Letters, 86 (2) :118-122
1982

62.

Winter, R.; Barnes, Ian; Fink, Ewald H.; Wildt, J{ü}rgen; Zabel, Friedhelm
b\(^{1}\)\(\Sigma\)\(^{+}\) and a\(^{1}\)\(\Delta\) emissions from group VI-VI diatomic molecules: b0\(^{+}\) → X\(_{1}\)0\(^{+}\), X\(_{2}\)1 emissions of TeO and TeS
Journal of Molecular Structure, 80 :75-82
1982

61.

Winter, R.; Barnes, Ian; Fink, Ewald H.; Wildt, J{ü}rgen; Zabel, Friedhelm
b\(^{1}\)\(\Sigma\)\(^{+}\) and a\(^{1}\)\(\Delta\) emissions from group VI-VI diatomic molecules: b0\(^{+}\) → X\(_{1}\)0\(^{+}\), X\(_{2}\)1 emissions of TeO and TeS
Journal of Molecular Structure, 80 :75-82
1982

60.

Kruse, H.; Winter, R.; Fink, Ewald H.; Wildt, J{ü}rgen; Zabel, Friedhelm
b\(^{1}\)\(\Sigma\)\(^{+}\) emissions from group V-VII diatomic molecules: b0\(^{+}\) → X\(_{1}\)0\(^{+}\), X\(_{2}\)0\(^{+}\) emissions of SbBr
Chemical Physics Letters, 93 (5) :475-479
1982

59.

Kruse, H.; Winter, R.; Fink, Ewald H.; Wildt, J{ü}rgen; Zabel, Friedhelm
b\(^{1}\)\(\Sigma\)\(^{+}\) emissions from group V-VII diatomic molecules: b0\(^{+}\) → X\(_{1}\)0\(^{+}\), X\(_{2}\)0\(^{+}\) emissions of SbBr
Chemical Physics Letters, 93 (5) :475-479
1982

58.

Winter, R.; Barnes, Ian; Fink, Ewald H.; Wildt, Jürgen; Zabel, Friedhelm
b1Σ+ and a1Δ emissions from group VI-VI diatomic molecules b0g+ → X21g emissions of Se2 and Te2
Chemical Physics Letters, 86 (2) :118-122
1982

57.

Winter, R.; Barnes, Ian; Fink, Ewald H.; Wildt, Jürgen; Zabel, Friedhelm
b1Σ+ and a1Δ emissions from group VI-VI diatomic molecules: b0+ → X10+, X21 emissions of TeO and TeS
Journal of Molecular Structure, 80 :75-82
1982

56.

Kruse, H.; Winter, R.; Fink, Ewald H.; Wildt, Jürgen; Zabel, Friedhelm
b1Σ+ emissions from group V-VII diatomic molecules: b0+ → X10+, X20+ emissions of SbBr
Chemical Physics Letters, 93 (5) :475-479
1982

55.

Tausch, Michael W.
Modelle im Chemieunterricht
Der mathematische und naturwissenschaftliche Unterricht (MNU), 35 :226
1982

54.

Becker, Karl Heinz; Horie, O.; Schmidt, V. H.; Wiesen, Peter
Spectroscopic identification of C\(_{2}\)O radicals in the C\(_{3}\)O\(_{2}\) + O flame system by laser-induced fluorescence
Chemical Physics Letters, 90 (1) :64-68
1982

53.

Becker, Karl Heinz; Horie, O.; Schmidt, V. H.; Wiesen, Peter
Spectroscopic identification of C\(_{2}\)O radicals in the C\(_{3}\)O\(_{2}\) + O flame system by laser-induced fluorescence
Chemical Physics Letters, 90 (1) :64-68
1982

52.

Becker, Karl Heinz; Horie, O.; Schmidt, V. H.; Wiesen, Peter
Spectroscopic identification of C2O radicals in the C3O2 + O flame system by laser-induced fluorescence
Chemical Physics Letters, 90 (1) :64-68
1982

51.

Jensen, Per; Brodersen, Svend
The \(\nu\)\(_{5}\) Raman band of CH\(_{3}\)CD\(_{3}\)
Journal of Raman Spectroscopy, 12 (3) :295-299
1982

50.

Jensen, Per; Brodersen, Svend
The \(\nu\)\(_{5}\) Raman band of CH\(_{3}\)CD\(_{3}\)
Journal of Raman Spectroscopy, 12 (3) :295-299
1982

49.

Jensen, Per; Bunker, Philip R.; Hoy, A. R.
The equilibrium geometry, potential function, and rotation?vibration energies of CH\(_{2}\) in the X\verb=~=\(^{3}\)B\(_{1}\) ground state
The Journal of Chemical Physics, 77 (11) :5370-5374
1982

48.

Jensen, Per; Bunker, Philip R.; Hoy, A. R.
The equilibrium geometry, potential function, and rotation?vibration energies of CH\(_{2}\) in the X\verb=~=\(^{3}\)B\(_{1}\) ground state
The Journal of Chemical Physics, 77 (11) :5370-5374
1982

47.

Jensen, Per; Bunker, Philip R.; Hoy, A. R.
The equilibrium geometry, potential function, and rotation?vibration energies of CH2 in the X~3B1 ground state
The Journal of Chemical Physics, 77 (11) :5370-5374
1982

46.

Jensen, Per; Bunker, Philip R.
The geometry and the inversion potential function of formaldehyde in the and electronic states
Journal of Molecular Spectroscopy, 94 (1) :114-125
1982

45.

Jensen, Per; Bunker, Philip R.
The geometry and the inversion potential function of formaldehyde in the and electronic states
Journal of Molecular Spectroscopy, 94 (1) :114-125
1982

44.

Jensen, Per; Bunker, Philip R.
The geometry and the inversion potential function of formaldehyde in the and electronic states
Journal of Molecular Spectroscopy, 94 (1) :114-125
1982

43.

Jensen, Per; Bunker, Philip R.
The geometry and the out-of-plane bending potential function of thioformaldehyde in the A\verb=~=\(^{1}\)A\(_{2}\) and a\verb=~=\(^{3}\)A\(_{2}\) electronic states
Journal of Molecular Spectroscopy, 95 (1) :92-100
1982