Timing of transients: quantifying reaching times and transient behavior in complex systems

In dynamical systems, one may ask how long it takes for a trajectory to reach the attractor, i.e. how long it spends in the transient phase. Although for a single trajectory the mathematically precise answer may be infinity, it still makes sense to compare different trajectories and quantify which o...

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Main Authors: Tim Kittel, Jobst Heitzig, Kevin Webster, Jürgen Kurths
Format: Article
Language:English
Published: IOP Publishing 2017-01-01
Series:New Journal of Physics
Subjects:
Online Access:https://doi.org/10.1088/1367-2630/aa7b61
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author Tim Kittel
Jobst Heitzig
Kevin Webster
Jürgen Kurths
author_facet Tim Kittel
Jobst Heitzig
Kevin Webster
Jürgen Kurths
author_sort Tim Kittel
collection DOAJ
description In dynamical systems, one may ask how long it takes for a trajectory to reach the attractor, i.e. how long it spends in the transient phase. Although for a single trajectory the mathematically precise answer may be infinity, it still makes sense to compare different trajectories and quantify which of them approaches the attractor earlier. In this article, we categorize several problems of quantifying such transient times. To treat them, we propose two metrics, area under distance curve and regularized reaching time, that capture two complementary aspects of transient dynamics. The first, area under distance curve, is the distance of the trajectory to the attractor integrated over time. It measures which trajectories are ‘reluctant’, i.e. stay distant from the attractor for long, or ‘eager’ to approach it right away. Regularized reaching time, on the other hand, quantifies the additional time (positive or negative) that a trajectory starting at a chosen initial condition needs to approach the attractor as compared to some reference trajectory. A positive or negative value means that it approaches the attractor by this much ‘earlier’ or ‘later’ than the reference, respectively. We demonstrated their substantial potential for application with multiple paradigmatic examples uncovering new features.
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spelling doaj.art-9bd4c4db6bd64c8bbb6bd5940896796c2023-08-08T14:53:02ZengIOP PublishingNew Journal of Physics1367-26302017-01-0119808300510.1088/1367-2630/aa7b61Timing of transients: quantifying reaching times and transient behavior in complex systemsTim Kittel0Jobst Heitzig1Kevin Webster2Jürgen Kurths3Potsdam Institute for Climate Impact Research , Telegrafenberg A31—(PO) Box 60 12 03, D-14412 Potsdam, Germany; Institut für Physik , Humboldt-Universität zu Berlin, Newtonstraße 15, D-12489 Berlin, GermanyPotsdam Institute for Climate Impact Research , Telegrafenberg A31—(PO) Box 60 12 03, D-14412 Potsdam, GermanyPotsdam Institute for Climate Impact Research , Telegrafenberg A31—(PO) Box 60 12 03, D-14412 Potsdam, GermanyPotsdam Institute for Climate Impact Research , Telegrafenberg A31—(PO) Box 60 12 03, D-14412 Potsdam, Germany; Institut für Physik , Humboldt-Universität zu Berlin, Newtonstraße 15, D-12489 Berlin, Germany; Institute for Complex Systems and Mathematical Biology, University of Aberdeen , Aberdeen AB24 3UE, United KingdomIn dynamical systems, one may ask how long it takes for a trajectory to reach the attractor, i.e. how long it spends in the transient phase. Although for a single trajectory the mathematically precise answer may be infinity, it still makes sense to compare different trajectories and quantify which of them approaches the attractor earlier. In this article, we categorize several problems of quantifying such transient times. To treat them, we propose two metrics, area under distance curve and regularized reaching time, that capture two complementary aspects of transient dynamics. The first, area under distance curve, is the distance of the trajectory to the attractor integrated over time. It measures which trajectories are ‘reluctant’, i.e. stay distant from the attractor for long, or ‘eager’ to approach it right away. Regularized reaching time, on the other hand, quantifies the additional time (positive or negative) that a trajectory starting at a chosen initial condition needs to approach the attractor as compared to some reference trajectory. A positive or negative value means that it approaches the attractor by this much ‘earlier’ or ‘later’ than the reference, respectively. We demonstrated their substantial potential for application with multiple paradigmatic examples uncovering new features.https://doi.org/10.1088/1367-2630/aa7b61early-warning signalscomplex systemsnonlinear dynamicsordinary differential equationsstability against shocks05.45.-a
spellingShingle Tim Kittel
Jobst Heitzig
Kevin Webster
Jürgen Kurths
Timing of transients: quantifying reaching times and transient behavior in complex systems
New Journal of Physics
early-warning signals
complex systems
nonlinear dynamics
ordinary differential equations
stability against shocks
05.45.-a
title Timing of transients: quantifying reaching times and transient behavior in complex systems
title_full Timing of transients: quantifying reaching times and transient behavior in complex systems
title_fullStr Timing of transients: quantifying reaching times and transient behavior in complex systems
title_full_unstemmed Timing of transients: quantifying reaching times and transient behavior in complex systems
title_short Timing of transients: quantifying reaching times and transient behavior in complex systems
title_sort timing of transients quantifying reaching times and transient behavior in complex systems
topic early-warning signals
complex systems
nonlinear dynamics
ordinary differential equations
stability against shocks
05.45.-a
url https://doi.org/10.1088/1367-2630/aa7b61
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