SeisSol is a software package for the simulation of seismic wave phenomena on unstructured grids, based on the discontinuous Galerkin method combined with ADER time discretization. A recent study shows that the intra-element performance of SeisSol is critical for its overall performance. Most of the element matrices are sparse operators implemented employing a standard sparse matrix storage sch...

Baxter’s Q-operator for the quantum transfer matrix of the XXZ spin-chain is constructed employing the representation theory of quantum groups. The spectrum of this Q-operator is discussed and novel functional relations which describe the finite temperature regime of the XXZ spin-chain are derived. For non-vanishing magnetic field the previously known Bethe ansatz equations can be replaced by a...

This study investigates whether, how, and why the matrix of correlations across international equity markets changes over time. A theoretical model is proposed to specify potential economic determinants of this correlation structure. The empirical validity of this economic model is investigated by employing daily returns for different national stock indexes, from 1972 through 1993, to construct...

We study the tunneling through an oscillating delta barrier. Using time peri-odicity of the model, the time-dependent Schrödinger equation is reduced to a simple but infinite matrix equation. Employing Toeplitz matrices methods, the infinite matrix is replaces by a 3×3 matrix, allowing an analytical solution. Looking at the frequency dependence of the transmission amplitudes, one observes a new...

We study the tunneling through an oscillating delta barrier. Using time peri-odicity of the model, the time-dependent Schrödinger equation is reduced to a simple but infinite matrix equation. Employing Toeplitz matrices methods, the infinite matrix is replaces by a 3×3 matrix, allowing an analytical solution. Looking at the frequency dependence of the transmission amplitudes, one observes a new...

The brain changes in response to experience and altered environment. To do that, the nervous system often remodels the structures of neuronal circuits. This structural plasticity of the neuronal circuits appears to be controlled not only by intrinsic factors, but also by extrinsic mechanisms including modification of the extracellular matrix. Recent studies employing a range of animal models im...

It is shown that e¢ cient GMM (generalized method of moments) estimation of a linear model corresponds to standard IV (instrumental variables) estimation of this model, after transforming it such (as in GLS) that its resulting disturbances have a scalar covariance matrix, while using as instruments the original instruments linearly transformed by the transpose of the inverse of the matrix used ...

Linear and unsupervised dimensionality reduction via matrix factorization with nonnegativity constraints is studied. Because of these constraints, it stands apart from other linear dimensionality reduction methods. Here we explore nonnegative matrix factorization in combination with three nearest-neighbor classifiers for protein fold recognition. Since typically matrix factorization is iterativ...

The problems on global dissipativity and global exponential dissipativity are investigated for uncertain discrete-time neural networks with time-varying delays and general activation functions. By constructing appropriate Lyapunov-Krasovskii functionals and employing linear matrix inequality technique, several new delay-dependent criteria for checking the global dissipativity and global exponen...