Browsing Mathematics by Title
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Contextdependent interaction leads to emergent search behavior in social aggregates
(National Academy of Sciences, 2009)Locating the source of an advected chemical signal is a common challenge facing many living organisms. When the advecting medium is characterized by either high Reynolds number or high Peclet number, the task becomes highly ... 
Control of scrollwave turbulence using resonant perturbations
(American Physical Society, 2008)Turbulence of scroll waves is a sort of spatiotemporal chaos that exists in threedimensional excitable media. Cardiac tissue and the BelousovZhabotinsky reaction are examples of such media. In cardiac tissue, chaotic ... 
Controlbased continuation of unstable periodic orbits
(American Society of Mechanical Engineers (ASME), 2011)We present an experimental procedure to track periodic orbits through a fold (saddlenode) bifurcation and demonstrate it with a parametrically excited pendulum experiment where the tracking parameter is the amplitude of ... 
Controlling unstable chaos: stabilizing chimera states by feedback
(American Physical Society, 2014)We present a control scheme that is able to find and stabilize an unstable chaotic regime in a system with a large number of interacting particles. This allows us to track a high dimensional chaotic attractor through a ... 
Convergence to local random attractors
(Taylor & Francis, 2003)Random attractors allow one to classify qualitative and quantitative aspects of the longtime behaviour of stochastically forced systems viewed as random dynamical systems (RDS) in an analogous way to attractors for ... 
Coronal Alfvén speed determination : consistency between seismology using AIA/SDO transverse loop oscillations and magnetic extrapolation
(American Astronomical Society / IOP Publishing, 2013)Two transversely oscillating coronal loops are investigated in detail during a flare on the 2011 September 6 using data from the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory. We compare two ... 
Correcting the finiteensemble bias of the ignorance score
(Royal Meteorological Society, 2015)This study considers the application of the Ignorance Score (also known as the Logarithmic Score) in the context of ensemble verification. In particular, we consider the case where an ensemble forecast is transformed to a ... 
A counterexample to "positive realness preserving model reduction with ℋ∞ norm error bounds"
(Institute of Electrical and Electronics Engineers (IEEE), 2011)We provide a counterexample to the H∞ error bound for the difference of a positive real transfer function and its positive real balanced truncation stated in “Positive realness preserving model reduction with H∞ norm error ... 
Countertraveling waves in rotating RayleighBénard convection.
(American Physical Society, 2008)Linear and nonlinear countertraveling waves in a fluidfilled annular cylinder with realistic noslip boundary conditions uniformly heated from below and rotating about a vertical axis are investigated. When the gap of ... 
Criteria for robustness of heteroclinic cycles in neural microcircuits.
(BioMed Central / SpringerOpen, 2011)We introduce a test for robustness of heteroclinic cycles that appear in neural microcircuits modeled as coupled dynamical cells. Robust heteroclinic cycles (RHCs) can appear as robust attractors in LotkaVolterratype ... 
Critical fronts in initiation of excitation waves
(American Physical Society, 2007)We consider the problem of initiation of propagating waves in a onedimensional excitable fiber. In the FitzHughNagumo theory, the key role is played by "critical nucleus" and "critical pulse" solutions whose (center) ... 
Cycling chaos: its creation, persistence and loss of stability in a model of nonlinear magnetoconvection
(Elsevier, 1998)We examine a model system where attractors may consist of a heteroclinic cycle between chaotic sets; this `cycling chaos' manifests itself as trajectories that spend increasingly long periods lingering near chaotic invariant ... 
Cycling chaotic attractors in two models for dynamics with invariant subspaces
(American Institute of Physics, 2004)Nonergodic attractors can robustly appear in symmetric systems as structurally stable cycles between saddletype invariant sets. These saddles may be chaotic giving rise to "cycling chaos." The robustness of such attractors ... 
Damped large amplitude transverse oscillations in an EUV solar prominence, triggered by largescale transient coronal waves
(EDP Sciences, 2011)Aims. We investigate two successive trains of large amplitude transverse oscillations in an arched EUV prominence, observed with SoHO/EIT on the northeast solar limb on 30 July 2005. The oscillatory trains are triggered ... 
Decelerating defects and nonergodic critical behaviour in a unidirectionally coupled map lattice
(Elsevier, 2003)We examine a coupled map lattice (CML) consisting of an infinite chain of logistic maps coupled in one direction by inhibitory coupling. We find that for sufficiently strong coupling strength there are dynamical states ... 
Declining summer snowfall in the Arctic: Causes, impacts and feedbacks
(Springer Verlag, 2012)Recent changes in the Arctic hydrological cycle are explored using in situ observations and an improved atmospheric reanalysis data set, ERAInterim. We document a pronounced decline in summer snowfall over the Arctic Ocean ... 
Dengue epidemic early warning system for Brazil
(UNISDR Scientific and Technical Advisory Group, 2015)The problem Brazil has reported more cases of dengue fever than anywhere else in the world this century1. Many cities have tropical and subtropical climate conditions that allow the dengue mosquito to thrive during warmer, ... 
Dependency of global mean precipitation on surface temperature
(American Geophysical Union (AGU), 2008)We investigate the causes of temperature dependent changes in global precipitation in contemporary General Circulation Models (GCMs) subjected to a doubling of atmospheric CO2 concentration. By analyzing the energy budget ... 
Designing the dynamics of globally coupled oscillators
(Oxford University Press, 2009)A method for designing cluster states with prescribed stability is presented for coupled phase oscillator systems with alltoall coupling. We determine criteria for the coupling function that ensure the existence and ... 
Detection of ultralongperiod oscillations in an EUV filament
(EDP Sciences, 2004)We report the first detection of longperiod (827 h) oscillatory intensity variations in a coronal filament. The filament is observed continuously as it crosses the solar disk in a 12mincadence SoHO/EIT 195 Å uninterrupted ...