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

92.

Winter, R.; Kruse, H.; Fink, Ewald H.; Wildt, Jürgen
b1Σ+ Emissions from group V-VII diatomic molecules: b0+ → X10+ emission of Pl
Chemical Physics Letters, 102 (5) :404-408
1983

91.

Tausch, Michael W.
Chemische Solarenergiespeicherung in Valenzisomeren
Praxis der Naturwissenschaften (Chemie), 32 :79
1983

90.

Tausch, Michael W.
DER UV-TAUCHLAMPENREAKTOR FÜR PHOTOCHEMISCHE SCHULVERSUCHE, Monographie mit Versuchsanleitungen und didaktischen Hinweisen
Publisher: SCS Jürgens\&Co KG, Bremen
1983

89.

Jensen, Per
HCNO as a semirigid bender: The degenerate \(\nu\)\(_{4}\) state
Journal of Molecular Spectroscopy, 101 (2) :422-439
1983

88.

Jensen, Per
HCNO as a semirigid bender: The degenerate \(\nu\)\(_{4}\) state
Journal of Molecular Spectroscopy, 101 (2) :422-439
1983

87.

Jensen, Per
HCNO as a semirigid bender: The degenerate ν4 state
Journal of Molecular Spectroscopy, 101 (2) :422-439
1983

86.

Holstein, K. J.; Fink, Ewald H.; Wildt, J{ü}rgen; Winter, R.; Zabel, Friedhelm
Mechanisms of perhydroxyl HO\(_{2}\)(A\(^{2}\)A') excitation in various chemical systems
The Journal of Physical Chemistry, 87 (20) :3943-3948
1983

85.

Holstein, K. J.; Fink, Ewald H.; Wildt, J{ü}rgen; Winter, R.; Zabel, Friedhelm
Mechanisms of perhydroxyl HO\(_{2}\)(A\(^{2}\)A') excitation in various chemical systems
The Journal of Physical Chemistry, 87 (20) :3943-3948
1983

84.

Holstein, K. J.; Fink, Ewald H.; Wildt, Jürgen; Winter, R.; Zabel, Friedhelm
Mechanisms of perhydroxyl HO2(A2A') excitation in various chemical systems
The Journal of Physical Chemistry, 87 (20) :3943-3948
1983

83.

Wildt, J{ü}rgen; Fink, Ewald H.; Winter, R.; Zabel, Friedhelm
Radiative lifetime and quenching of SO(b\(^{1}\)\(\Sigma\)\(^{+}\),\(\nu\)'=0)
Chemical Physics, 80 (1-2) :167-175
1983

82.

Wildt, J{ü}rgen; Fink, Ewald H.; Winter, R.; Zabel, Friedhelm
Radiative lifetime and quenching of SO(b\(^{1}\)\(\Sigma\)\(^{+}\),\(\nu\)'=0)
Chemical Physics, 80 (1-2) :167-175
1983

81.

Wildt, Jürgen; Fink, Ewald H.; Winter, R.; Zabel, Friedhelm
Radiative lifetime and quenching of SO(b1Σ+,ν'=0)
Chemical Physics, 80 (1-2) :167-175
1983

80.

Wildt, J{ü}rgen; Bielefeld, M.; Fink, Ewald H.; Winter, R.; Zabel, Friedhelm
Radiative livetimes of the metastable b\(^{1}\)\(\Sigma\) states of SO, SeO, PCl and PBr
Bulletin des Sociétés Chimiques Belges, 92 (6-7) :523-524
1983

79.

Wildt, J{ü}rgen; Bielefeld, M.; Fink, Ewald H.; Winter, R.; Zabel, Friedhelm
Radiative livetimes of the metastable b\(^{1}\)\(\Sigma\) states of SO, SeO, PCl and PBr
Bulletin des Sociétés Chimiques Belges, 92 (6-7) :523-524
1983

78.

Wildt, Jürgen; Bielefeld, M.; Fink, Ewald H.; Winter, R.; Zabel, Friedhelm
Radiative livetimes of the metastable b1Σ states of SO, SeO, PCl and PBr
Bulletin des Sociétés Chimiques Belges, 92 (6-7) :523-524
1983

77.

[german] Tausch, Michael W.
Strukturaufklärung in der organischen Chemie - Ermittlung der Strukturformeln von Maleinsäure und Fumarsäure
Praxis der Naturwissenschaften (Chemie), 32 :44
1983

76.

Holstein, K. J.; Fink, Ewald H.; Zabel, Friedhelm
The \(\nu\)\(_{3}\) vibration of electronically excited HO\(_{2}\)(A\(^{2}\)A')
Journal of Molecular Spectroscopy, 99 (1) :231-234
1983

75.

Holstein, K. J.; Fink, Ewald H.; Zabel, Friedhelm
The \(\nu\)\(_{3}\) vibration of electronically excited HO\(_{2}\)(A\(^{2}\)A')
Journal of Molecular Spectroscopy, 99 (1) :231-234
1983

74.

Jensen, Per; Bunker, Philip R.
The application of the nonrigid bender Hamiltonian to a quasilinear molecule
Journal of Molecular Spectroscopy, 99 (2) :348-356
1983

73.

Jensen, Per; Bunker, Philip R.
The application of the nonrigid bender Hamiltonian to a quasilinear molecule
Journal of Molecular Spectroscopy, 99 (2) :348-356
1983

72.

Jensen, Per; Bunker, Philip R.
The application of the nonrigid bender Hamiltonian to a quasilinear molecule
Journal of Molecular Spectroscopy, 99 (2) :348-356
1983

71.

Winnewisser, Brenda P.; Jensen, Per
The infrared spectrum of fulminic acid, HCNO, in the \(\nu\)\(_{4}\) fundamental region
Journal of Molecular Spectroscopy, 101 (2) :408-421
1983

70.

Winnewisser, Brenda P.; Jensen, Per
The infrared spectrum of fulminic acid, HCNO, in the \(\nu\)\(_{4}\) fundamental region
Journal of Molecular Spectroscopy, 101 (2) :408-421
1983

69.

Winnewisser, Brenda P.; Jensen, Per
The infrared spectrum of fulminic acid, HCNO, in the ν4 fundamental region
Journal of Molecular Spectroscopy, 101 (2) :408-421
1983

68.

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