CHAOS: All Topics http://scitation.aip.org/ CHAOS: All Topics The computation of finite-time Lyapunov exponents on unstructured meshes and for non-Euclidean manifolds http://link.aip.org/link/?CHA/20/017505/1&agg=rss Francois Lekien and Shane D. Ross<br/> We generalize the concepts of finite-time Lyapunov exponent (FTLE) and Lagrangian coherent structures to arbitrary Riemannian manifolds. The methods are illustrated for convection cells on cylinders and Mobius strips, as well as for the splitting of the Antarctic polar vortex in the spherical strato ... [Chaos 20, 017505 (2010)] published Mon Feb 8, 2010. An automated algorithm for the generation of dynamically reconstructed trajectories http://link.aip.org/link/?CHA/20/013107/1&agg=rss C. Komalapriya, M. C. Romano, M. Thiel, N. Marwan, J. Kurths et al.<br/> The lack of long enough data sets is a major problem in the study of many real world systems. As it has been recently shown [C. Komalapriya, M. Thiel, M. C. Romano, N. Marwan, U. Schwarz, and J. Kurths, Phys. Rev. E 78, 066217 (2008)], this problem can be overcome in the case of ergodic systems if a ... [Chaos 20, 013107 (2010)] published Wed Feb 3, 2010. Geometry of repeated measurements in chaotic systems http://link.aip.org/link/?CHA/20/013106/1&agg=rss P.-M. Binder and B. D. Wissman<br/> We use joint probability matrices for measurements at different times to describe chaotic systems. By coarse graining the range of the measured variable into uniformly sized bins we can generate matrices that contain both topological and metric information about the systems being studied. Armed with ... [Chaos 20, 013106 (2010)] published Tue Jan 26, 2010. Chaotic operation by a single transistor circuit in the reverse active region http://link.aip.org/link/?CHA/20/013105/1&agg=rss M. P. Hanias, I. L. Giannis, and G. S. Tombras<br/> In this paper, we present an externally triggered experimental chaotic circuit with a bipolar junction transistor operating in its reverse active region in order to investigate for possible control features in its output phase portraits. Nonlinear time series modeling techniques are applied to analy ... [Chaos 20, 013105 (2010)] published Wed Jan 20, 2010. Weak signal detection based on the information fusion and chaotic oscillator http://link.aip.org/link/?CHA/20/013104/1&agg=rss Xiuqiao Xiang and Baochang Shi<br/> Based on the chaotic oscillator, a method for weak signal detection using information fusion technology is proposed in this paper. On the one hand, various methods are employed to the amplitude detection of the same weak periodic signal, then the detection outcomes are fused by the adaptive weighted ... [Chaos 20, 013104 (2010)] published Tue Jan 19, 2010. Announcement: Focus Issue on Mesoscales in Complex Networks http://link.aip.org/link/?CHA/20/010202/1&agg=rss J. A. Almendral, R. Criado, I. Leyva, J. M. Buldu, and I. Sendina Nadal<br/> Abstract not available. [Chaos 20, 010202 (2010)] published Tue Jan 19, 2010. The stability of adaptive synchronization of chaotic systems http://link.aip.org/link/?CHA/20/013103/1&agg=rss Francesco Sorrentino, Gilad Barlev, Adam B. Cohen, and Edward Ott<br/> In past works, various schemes for adaptive synchronization of chaotic systems have been proposed. The stability of such schemes is central to their utilization. As an example addressing this issue, we consider a recently proposed adaptive scheme for maintaining the synchronized state of identical c ... [Chaos 20, 013103 (2010)] published Thu Jan 14, 2010. Announcement: Focus Issue on Dynamics in Systems Biology http://link.aip.org/link/?CHA/20/010201/1&agg=rss C. A. Brackley, O. Ebenhoh, C. Grebogi, A. Moura, M. C. Romano et al.<br/> Abstract not available. [Chaos 20, 010201 (2010)] published Thu Jan 14, 2010. Erratum: A simple sequential-binding model for calcium puffs [Chaos 19, 037109 (2009)] http://link.aip.org/link/?CHA/20/019901/1&agg=rss D. Swaminathan, G. Ullah, and P. Jung<br/> Abstract not available. [Chaos 20, 019901 (2010)] published Tue Jan 5, 2010. Detecting dynamical boundaries from kinematic data in biomechanics http://link.aip.org/link/?CHA/20/017507/1&agg=rss Shane D. Ross, Martin L. Tanaka, and Carmine Senatore<br/> Ridges in the state space distribution of finite-time Lyapunov exponents can be used to locate dynamical boundaries. We describe a method for obtaining dynamical boundaries using only trajectories reconstructed from time series, expanding on the current approach which requires a vector field in the ... [Chaos 20, 017507 (2010)] published Tue Jan 5, 2010. Introduction to Focus Issue: Lagrangian Coherent Structures http://link.aip.org/link/?CHA/20/017501/1&agg=rss Thomas Peacock and John Dabiri<br/> The topic of Lagrangian coherent structures (LCS) has been a rapidly growing area of research in nonlinear dynamics for almost a decade. It provides a means to rigorously define and detect transport barriers in dynamical systems with arbitrary time dependence and has a wealth of applications, partic ... [Chaos 20, 017501 (2010)] published Tue Jan 5, 2010. Fast computation of finite-time Lyapunov exponent fields for unsteady flows http://link.aip.org/link/?CHA/20/017503/1&agg=rss Steven L. Brunton and Clarence W. Rowley<br/> This paper presents new efficient methods for computing finite-time Lyapunov exponent (FTLE) fields in unsteady flows. The methods approximate the particle flow map, eliminating redundant particle integrations in neighboring flow map calculations. Two classes of flow map approximations are investiga ... [Chaos 20, 017503 (2010)] published Tue Jan 5, 2010. Using hyperbolic Lagrangian coherent structures to investigate vortices in bioinspired fluid flows http://link.aip.org/link/?CHA/20/017510/1&agg=rss Melissa A. Green, Clarence W. Rowley, and Alexander J. Smits<br/> We use direct Lyapunov exponents to identify Lagrangian coherent structures (LCSs) in a bioinspired fluid flow: the wakes of rigid pitching panels with a trapezoidal planform geometry chosen to model idealized fish caudal fins. When compared with commonly used Eulerian criteria, the Lagrangian metho ... [Chaos 20, 017510 (2010)] published Tue Jan 5, 2010. A ridge tracking algorithm and error estimate for efficient computation of Lagrangian coherent structures http://link.aip.org/link/?CHA/20/017504/1&agg=rss Doug Lipinski and Kamran Mohseni<br/> A ridge tracking algorithm for the computation and extraction of Lagrangian coherent structures (LCS) is developed. This algorithm takes advantage of the spatial coherence of LCS by tracking the ridges which form LCS to avoid unnecessary computations away from the ridges. We also make use of the tem ... [Chaos 20, 017504 (2010)] published Tue Jan 5, 2010. Generation of solitons and breathers in the extended Kortewegde Vries equation with positive cubic nonlinearity http://link.aip.org/link/?CHA/20/013102/1&agg=rss R. Grimshaw, A. Slunyaev, and E. Pelinovsky<br/> The initial-value problem for box-like initial disturbances is studied within the framework of an extended Kortewegde Vries equation with both quadratic and cubic nonlinear terms, also known as the Gardner equation, for the case when the cubic nonlinear coefficient has the same sign as the linear di ... [Chaos 20, 013102 (2010)] published Tue Jan 5, 2010. Braids of entangled particle trajectories http://link.aip.org/link/?CHA/20/017516/1&agg=rss Jean-Luc Thiffeault<br/> In many applications, the two-dimensional trajectories of fluid particles are available, but little is known about the underlying flow. Oceanic floats are a clear example. To extract quantitative information from such data, one can measure single-particle dispersion coefficients, but this only uses ... [Chaos 20, 017516 (2010)] published Tue Jan 5, 2010. Using Lagrangian coherent structures to analyze fluid mixing by cilia http://link.aip.org/link/?CHA/20/017511/1&agg=rss Sarah Lukens, Xingzhou Yang, and Lisa Fauci<br/> Motivated by the desire to understand the fluid flow within the airway surface liquid of the lung, we consider the flow generated by a computational model of a motile, internally actuated cilium. The cilium, along with a mucus layer modeled by linear elastic elements, is coupled to a viscous, incomp ... [Chaos 20, 017511 (2010)] published Tue Jan 5, 2010. A Lagrangian approach to identifying vortex pinch-off http://link.aip.org/link/?CHA/20/017513/1&agg=rss Clara O'Farrell and John O. Dabiri<br/> A criterion for identifying vortex ring pinch-off based on the Lagrangian coherent structures (LCSs) in the flow is proposed and demonstrated for a piston-cylinder arrangement with a piston stroke to diameter (L/D) ratio of [approximate]12. It is found that the appearance of a new disconnected LCS a ... [Chaos 20, 017513 (2010)] published Tue Jan 5, 2010. Computational analysis of an aortic valve jet with Lagrangian coherent structures http://link.aip.org/link/?CHA/20/017512/1&agg=rss Shawn C. Shadden, Matteo Astorino, and Jean-Frederic Gerbeau<br/> Important progress has been achieved in recent years in simulating the fluid-structure interaction around cardiac valves. An important step in making these computational tools useful to clinical practice is the development of postprocessing techniques to extract clinically relevant information from ... [Chaos 20, 017512 (2010)] published Tue Jan 5, 2010. Accurate extraction of Lagrangian coherent structures over finite domains with application to flight data analysis over Hong Kong International Airport http://link.aip.org/link/?CHA/20/017502/1&agg=rss Wenbo Tang, Pak Wai Chan, and George Haller<br/> Locating Lagrangian coherent structures (LCS) for dynamical systems defined on a spatially limited domain present a challenge because trajectory integration must be stopped at the boundary for lack of further velocity data. This effectively turns the domain boundary into an attractor, introduces edg ... [Chaos 20, 017502 (2010)] published Tue Jan 5, 2010. Fluid transport and coherent structures of translating and flapping wings http://link.aip.org/link/?CHA/20/017509/1&agg=rss Jeff D. Eldredge and Kwitae Chong<br/> The Lagrangian coherent structures (LCSs) of simple wing cross sections in various low Reynolds number motions are extracted from high-fidelity numerical simulation data and examined in detail. The entrainment process in the wake of a translating ellipse is revealed by studying the relationship betw ... [Chaos 20, 017509 (2010)] published Tue Jan 5, 2010.