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



1988

216.

Wildt, Jürgen; Bednarek, G.; Fink, Ewald H.; Wayne, Richard P.
Laser excitation of O2(b1Σg+, v'=0,1,2) - rates and channels of energy transfer and quenching
Chemical Physics, 122 (3) :463-470
1988

215.

Heilmann, Margareta
Lp-saturation of some modified Bernstein operators
Journal of Approximation Theory, 54 (3) :260-273
1988
ISSN: 0021-9045

214.

Weinmüller, E.; Winkler, E.
Path-following Algorithm for Singular Boundary Value Problems
ZAMM, 68 :527--537
1988

213.

Becker, Karl Heinz; Brockmann, Klaus Josef; Wiesen, Peter
Spectroscopic identification of C(\(^{3}\)P) atoms in halogenomethane + H flame systems and measurements of C(\(^{3}\)P) reaction rate constants by two-photon laser-induced fluorescence
Journal of the Chemical Society, Faraday Transactions 2, 84 (5) :455-461
1988

212.

Becker, Karl Heinz; Brockmann, Klaus Josef; Wiesen, Peter
Spectroscopic identification of C(\(^{3}\)P) atoms in halogenomethane + H flame systems and measurements of C(\(^{3}\)P) reaction rate constants by two-photon laser-induced fluorescence
Journal of the Chemical Society, Faraday Transactions 2, 84 (5) :455-461
1988

211.

Becker, Karl Heinz; Brockmann, Klaus Josef; Wiesen, Peter
Spectroscopic identification of C(3P) atoms in halogenomethane + H flame systems and measurements of C(3P) reaction rate constants by two-photon laser-induced fluorescence
Journal of the Chemical Society, Faraday Transactions 2, 84 (5) :455-461
1988

210.

Fink, Ewald H.; Setzer, Klaus-Dieter; Kottsieper, U.; Ramsay, D. A.; Vervloet, M.
The a\(^{1}\)\(\Delta\)(a2)-X\(^{3}\)\(\Sigma\)\(^{-}\)(X\(_{2}\)1) electronic band system of selenium monoxide
Journal of Molecular Spectroscopy, 131 (1) :127-132
1988

209.

Fink, Ewald H.; Setzer, Klaus-Dieter; Kottsieper, U.; Ramsay, D. A.; Vervloet, M.
The a\(^{1}\)\(\Delta\)(a2)-X\(^{3}\)\(\Sigma\)\(^{-}\)(X\(_{2}\)1) electronic band system of selenium monoxide
Journal of Molecular Spectroscopy, 131 (1) :127-132
1988

208.

Fink, Ewald H.; Setzer, Klaus-Dieter; Kottsieper, U.; Ramsay, D. A.; Vervloet, M.
The a1Δ(a2)-X3Σ-(X21) electronic band system of selenium monoxide
Journal of Molecular Spectroscopy, 131 (1) :127-132
1988

207.

Jensen, Per; Bunker, Philip R.
The potential surface and stretching frequencies X\verb=~=\(^{3}\)B\(_{1}\) methylene (CH\(_{2}\)) determined from experiment using the Morse oscillator-rigid bender internal dynamics Hamiltonian
The Journal of Chemical Physics, 89 (3) :1327-1332
1988

206.

Jensen, Per; Bunker, Philip R.
The potential surface and stretching frequencies X\verb=~=\(^{3}\)B\(_{1}\) methylene (CH\(_{2}\)) determined from experiment using the Morse oscillator-rigid bender internal dynamics Hamiltonian
The Journal of Chemical Physics, 89 (3) :1327-1332
1988

205.

Jensen, Per; Bunker, Philip R.
The potential surface and stretching frequencies X~3B1 methylene (CH2) determined from experiment using the Morse oscillator-rigid bender internal dynamics Hamiltonian
The Journal of Chemical Physics, 89 (3) :1327-1332
1988
1987

204.

Spirko, Vladim{í}r; Cejchan, A.; Jensen, Per
A new Morse-oscillator based Hamiltonian for H\(_{3}\)\(^{+}\): Explicit expressions for some vibrational matrix elements
Journal of Molecular Spectroscopy, 124 (2) :430-436
1987

203.

Spirko, Vladim{í}r; Cejchan, A.; Jensen, Per
A new Morse-oscillator based Hamiltonian for H\(_{3}\)\(^{+}\): Explicit expressions for some vibrational matrix elements
Journal of Molecular Spectroscopy, 124 (2) :430-436
1987

202.

Spirko, Vladimír; Cejchan, A.; Jensen, Per
A new Morse-oscillator based Hamiltonian for H3+: Explicit expressions for some vibrational matrix elements
Journal of Molecular Spectroscopy, 124 (2) :430-436
1987

201.

McLean, A. D.; Bunker, Philip R.; Escribano, R. M.; Jensen, Per
An ab initio calculation of \(\nu\)\(_{1}\) and \(\nu\)\(_{3}\) for triplet methylene (X\verb=~=\(^{3}\)B\(_{1}\) CH\(_{2}\)) and the determination of the vibrationless singlet-triplet splitting Te (a\verb=~=\(^{1}\)A\(_{1}\))
The Journal of Chemical Physics, 87 (4) :2166-2169
1987

200.

McLean, A. D.; Bunker, Philip R.; Escribano, R. M.; Jensen, Per
An ab initio calculation of \(\nu\)\(_{1}\) and \(\nu\)\(_{3}\) for triplet methylene (X\verb=~=\(^{3}\)B\(_{1}\) CH\(_{2}\)) and the determination of the vibrationless singlet-triplet splitting Te (a\verb=~=\(^{1}\)A\(_{1}\))
The Journal of Chemical Physics, 87 (4) :2166-2169
1987

199.

Jensen, Per; Bunker, Philip R.; McLean, A. D.
An ab initio calculation of the rotation-vibration energies of singlet and triplet NH\(_{2}\)\(^{+}\) using the morbid Hamiltonian
Chemical Physics Letters, 141 (1-2) :53-57
1987

198.

Jensen, Per; Bunker, Philip R.; McLean, A. D.
An ab initio calculation of the rotation-vibration energies of singlet and triplet NH\(_{2}\)\(^{+}\) using the morbid Hamiltonian
Chemical Physics Letters, 141 (1-2) :53-57
1987

197.

Jensen, Per; Bunker, Philip R.; McLean, A. D.
An ab initio calculation of the rotation-vibration energies of singlet and triplet NH2+ using the morbid Hamiltonian
Chemical Physics Letters, 141 (1-2) :53-57
1987

196.

McLean, A. D.; Bunker, Philip R.; Escribano, R. M.; Jensen, Per
An ab initio calculation of ν1 and ν3 for triplet methylene (X~3B1 CH2) and the determination of the vibrationless singlet-triplet splitting Te (a~1A1)
The Journal of Chemical Physics, 87 (4) :2166-2169
1987

195.

Heilmann, Margareta
Approximation auf [0, ∞) durch das Verfahren der Operatoren vom Baskakov-Durrmeyer Typ
Universität Dortmund
1987

194.

Bunker, Philip R.; Jensen, Per; Kraemer, Wolfgang P.; Beardsworth, R.
Calculated rotation-vibration energies for HOC\(^{+}\)
Journal of Molecular Spectroscopy, 121 (2) :450-452
1987

193.

Bunker, Philip R.; Jensen, Per; Kraemer, Wolfgang P.; Beardsworth, R.
Calculated rotation-vibration energies for HOC\(^{+}\)
Journal of Molecular Spectroscopy, 121 (2) :450-452
1987

192.

Bunker, Philip R.; Jensen, Per; Kraemer, Wolfgang P.; Beardsworth, R.
Calculated rotation-vibration energies for HOC+
Journal of Molecular Spectroscopy, 121 (2) :450-452
1987