a watermarking scheme for grayscale image isproposed based on a family of the chaotic maps and discretecosine transform. jacobian elliptic mapis employed to encrypt ofwatermarked logo. piecewise nonlinear chaotic map is also usedto determine the location of dct coefficients for the watermarkembedding. the purpose of this algorithm is to improve theshortcoming of watermarking such as small key s...

Chaotic advection in three-dimensional unsteady incompressible laminar flow By J U L Y A N H. E. C A R T W R I G H T1;2y , M A R I O F E I N G O L D3z , AND O R E S T E P I R O1;4{ 1Departament de Fı́sica, Universitat de les Illes Balears, 07071 Palma de Mallorca, Spain. 2Centre de Càlcul i Informatització, Universitat de les Illes Balears, 07071 Palma de Mallorca, Spain. 3Department of Physics,...

We study the occurence of delay mechanisms other than periodic orbits in systems with time dependent potentials that exhibit chaotic scattering. By using as model system two harmonically oscillating disks on a plane, we have found the existence of a mechanism not related to the periodic orbits of the system, that delays trajectories in the scattering region. This mechanism creates a fractal-lik...

Currently, the interest in monitoring the vibration of dynamical systems has been increasing. For example, large and complex air and space structures include vibration monitoring systems to forecast sudden failures. Such vibration monitoring is used to diagnose structural health by analyzing vibration characteristics (such as frequency and amplitude). Among the vibration characteristics used, t...

Shroud devices which are typical cyclic symmetric structures widely used to reduce the vibration of turbine blades in aero engines. Asymmetric rub-impact adjacent shrouds or aerodynamic excitation forces can excite bending-torsion coupling shrouded blades, will lead complex contact motions. The aim this paper is study dynamic characteristics using a numerical method. contact-separation transiti...

Cuspy triaxial potentials admit a large number of chaotic orbits, which moreover exhibit extreme “stickiness” that makes the process of chaotic mixing surprisingly inefficient. Environmental effects, modeled as noise and/or periodic driving, help accelerate phase space transport but probably not as much as in simpler potentials. This could mean that cuspy triaxial ellipticals cannot exist as ti...

Experiments and theory characterize the novel chaotic neoclassical transport scaling as νcB in contrast to traditional collisional neoclassical transport scaling as ν 1/2 c B−1/2. This chaotic transport occurs when local trapping separatrices have θ-variations or temporal fluctuations. Experiments observe bulk particle transport, damping of Langmuir waves and diocotron waves, and nonlinear wave...