Browsing Mathematics by Title
Now showing items 5776 of 357

Computation of the response functions of spiral waves in active media
(American Physical Society, 2009)Rotating spiral waves are a form of selforganization observed in spatially extended systems of physical, chemical, and biological natures. A small perturbation causes gradual change in spatial location of spiral's rotation ... 
A Computer Simulation Study of Anatomy Induced Drift of Spiral Waves in the Human Atrium
(Hindawi Publishing Corporation, 2014)The interaction of spiral waves of excitation with atrial anatomy remains unclear. This simulation study isolates the role of atrial anatomical structures on spiral wave spontaneous drift in the human atrium. We implemented ... 
Conditions for propagation and block of excitation in an asymptotic model of atrial tissue.
(2006)Detailed ionic models of cardiac cells are difficult for numerical simulations because they consist of a large number of equations and contain small parameters. The presence of small parameters, however, may be used for ... 
Conditions for sinktosource transitions and runaway feedbacks from the land carbon cycle
(Cambridge University Press, 200602)The first GCM climatecarbon cycle simulation indicated that the land biosphere could provide a significant acceleration of 21st century climate change (Cox et al. 2000). In this numerical experiment the carbon storage was ... 
Cone exchange transformations and boundedness of orbits
(Cambridge University Press, 2010)We introduce a class of twodimensional piecewise isometries on the plane that we refer to as cone exchange transformations (CETs). These are generalizations of interval exchange transformations (IETs) to 2D unbounded ... 
Confidence in Classification: A Bayesian Approach
(Springer Verlag, 2006)Bayesian classification is currently of considerable interest. It provides a strategy for eliminating the uncertainty associated with a particular choice of classifiermodel parameters, and is the optimal decisiontheoretic ... 
Confident interpretation of Bayesian decision tree ensembles for clinical applications
(Institute of Electrical and Electronics Engineers (IEEE), 2007)Bayesian averaging (BA) over ensembles of decision models allows evaluation of the uncertainty of decisions that is of crucial importance for safetycritical applications such as medical diagnostics. The interpretability ... 
A conjecture of Stanley on alternating permutations
(Electronic Journal of Combinatorics, 2007)We give two simple proofs of a conjecture of Richard Stanley concerning the equidistribution of derangements and alternating permutations with the maximal number of fixed points. 
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 ...