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A frequency domain analysis of slow coherency in networked systems

Min, Hancheng ; Pates, Richard LU and Mallada, Enrique (2025) In Automatica 174.
Abstract

Network coherence generally refers to the emergence of simple aggregated dynamical behaviors, despite heterogeneity in the dynamics of the subsystems that constitute the network. In this paper, we develop a general frequency domain framework to analyze and quantify the level of network coherence that a system exhibits by relating coherence with a low-rank property of the system's input–output response. More precisely, for a networked system with linear dynamics and coupling, we show that, as the network's frequency-dependent algebraic connectivity grows, the system transfer matrix converges to a rank-one transfer matrix representing the coherent behavior. Interestingly, the non-zero eigenvalue of such a rank-one matrix is given by the... (More)

Network coherence generally refers to the emergence of simple aggregated dynamical behaviors, despite heterogeneity in the dynamics of the subsystems that constitute the network. In this paper, we develop a general frequency domain framework to analyze and quantify the level of network coherence that a system exhibits by relating coherence with a low-rank property of the system's input–output response. More precisely, for a networked system with linear dynamics and coupling, we show that, as the network's frequency-dependent algebraic connectivity grows, the system transfer matrix converges to a rank-one transfer matrix representing the coherent behavior. Interestingly, the non-zero eigenvalue of such a rank-one matrix is given by the harmonic mean of individual nodal dynamics, and we refer to it as coherent dynamics. Our analysis unveils the frequency-dependent nature of coherence and a non-trivial interplay between dynamics and network topology. We further show that many networked systems can exhibit similar coherent behavior by establishing a concentration result in a setting with randomly chosen individual nodal dynamics.

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author
; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Large-scale networks, Linear/nonlinear model, Low-rank approximation, Multi-agent systems, Slow coherency
in
Automatica
volume
174
article number
112184
publisher
Elsevier
external identifiers
  • scopus:85216794057
ISSN
0005-1098
DOI
10.1016/j.automatica.2025.112184
language
English
LU publication?
yes
id
498de66e-520f-4ab0-8714-8cb667d2bbc4
date added to LUP
2025-03-21 09:41:33
date last changed
2025-04-04 14:20:39
@article{498de66e-520f-4ab0-8714-8cb667d2bbc4,
  abstract     = {{<p>Network coherence generally refers to the emergence of simple aggregated dynamical behaviors, despite heterogeneity in the dynamics of the subsystems that constitute the network. In this paper, we develop a general frequency domain framework to analyze and quantify the level of network coherence that a system exhibits by relating coherence with a low-rank property of the system's input–output response. More precisely, for a networked system with linear dynamics and coupling, we show that, as the network's frequency-dependent algebraic connectivity grows, the system transfer matrix converges to a rank-one transfer matrix representing the coherent behavior. Interestingly, the non-zero eigenvalue of such a rank-one matrix is given by the harmonic mean of individual nodal dynamics, and we refer to it as coherent dynamics. Our analysis unveils the frequency-dependent nature of coherence and a non-trivial interplay between dynamics and network topology. We further show that many networked systems can exhibit similar coherent behavior by establishing a concentration result in a setting with randomly chosen individual nodal dynamics.</p>}},
  author       = {{Min, Hancheng and Pates, Richard and Mallada, Enrique}},
  issn         = {{0005-1098}},
  keywords     = {{Large-scale networks; Linear/nonlinear model; Low-rank approximation; Multi-agent systems; Slow coherency}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Automatica}},
  title        = {{A frequency domain analysis of slow coherency in networked systems}},
  url          = {{http://dx.doi.org/10.1016/j.automatica.2025.112184}},
  doi          = {{10.1016/j.automatica.2025.112184}},
  volume       = {{174}},
  year         = {{2025}},
}