The main goal of developing an image watermarking technique is to satisfy both imperceptibility and robustness requirements. To achieve this goal, a hybrid DWT (discrete wavelet transform) SVD (singular value decomposition) and a logistic chaotic map based watermarking technique is proposed. In this approach, the watermark is not embedded directly on the wavelet coefficients but rather than the...

A new Jacobian approximation is developed for use in quasi-Newton methods for solving systems of nonlinear equations. The new hypersecant Jacobian approximation is intended for the special case where the evaluation of the functions whose roots are sought dominates the computation time, and additionally the Jacobian is sparse. One example of such a case is the solution of the discretized transpo...

We present a Hamiltonian framework for higher-dimensional vortex filaments (or membranes) and vortex sheets as singular 2-forms with support of codimensions 2 and 1, respectively, i.e., singular elements of the dual to the Lie algebra of divergence-free vector fields. It turns out that the localized induction approximation (LIA) of the hydrodynamical Euler equation describes the skew-mean-curva...

Magnet errors and off-center orbits through sextupoles perturb the dispersion and beta functions in a storage ring (SR), which affects machine performance. In a large ring such as the Advanced Photon Source (APS), the magnet errors are difficult to determine with beam-based methods. Also the non-zero orbit through sextupoles result from user requests for steering at light source points. For exp...

We consider the approximation of a coupled system of two singularly perturbed reaction-diffusion equations by the finite element method. The solution to such problems contains boundary layers which overlap and interact, and the numerical approximation must take this into account in order for the resulting scheme to converge uniformly with respect to the singular perturbation parameters. We pres...

The indirect boundary element method for the Helmholtz equation in three dimensions is of great interest and practical value for many problems in acoustics as it is capable of treating infinitely thin plates and allows coupling of interior and exterior scattering problems. In the present paper we provide a new approach for treatment of boundary integrals, including hypersingular, singular, and ...

The solution of the Stokes problem in three-dimensional domains with edges has anisotropic singular behaviour which is treated numerically by using anisotropic finite element meshes. The velocity is approximated by Crouzeix–Raviart (nonconforming P1) elements and the pressure by piecewise constants. This method is stable for general meshes (without minimal or maximal angle condition). Denoting ...

A scaling of a non-negative, square matrix A .. 0 is a matrix of the form DAD-I, where Dis a non~negatjve. non-singular, diagonal, square matrix. For a non.-negative, rectangular matrix B .. 0 we define a scaling to be a matrix CBEI where C and E are non-negative, non-singular, diagonal, square matrices of the corresponding dimension. (For square matrices the latter definition allows more scali...

We propose a fast approximation method of a softmax function with a very large vocabulary using singular value decomposition (SVD). SVD-softmax targets fast and accurate probability estimation of the topmost probable words during inference of neural network language models. The proposed method transforms the weight matrix used in the calculation of the output vector by using SVD. The approximat...