This paper is about the numerical simulation of nonlinear analog circuits with ”switch” components, such as diodes. A ”switch” component is an electrical device that may or may not conduct, depending on the state of the circuit. The problem with ”switch” components is that the topology of the circuit is variable and so, apparently, it is not possible to describe the system with a single differe...

In this paper, a novel improvement idea in image restoration by Non-Local means (NL-means) filter is proposed. Most of special image denoising techniques require a region size called neighborhood window for denoising, window-size selection is usually done by visual inspection based upon experience or hit and trial. It is shown in this paper that varying the window-size for each pixel according ...

Non-positive, Markovian semigroups are sometimes used to describe the time evolution of subsystems immersed in an external environment. A widely adopted prescription to avoid the appearance of negative probabilities is to eliminate from the admissible initial conditions those density matrices that would not remain positive by the action of the semigroup dynamics. Using a continuous variable mod...

We investigate theoretically the effect of a finite electric field on the resistivity of a disordered one-dimensional system in the variable-range hopping regime. We find that at low fields the transport is inhibited by rare fluctuations in the random distribution of localized states that create high-resistance breaks in the hopping network. As the field increases, the breaks become less resist...

We consider the problem of high-dimensional non-linear variable selection for supervised learning. Our approach is based on performing linear selection among exponentially many appropriately defined positive definite kernels that characterize non-linear interactions between the original variables. To select efficiently from these many kernels, we use the natural hierarchical structure of the pr...

Ruggero Vasile,1,* Stefano Olivares,2,3,4,† Matteo G. A. Paris,4,‡ and Sabrina Maniscalco5,1,§ 1Turku Centre for Quantum Physics, Department of Physics and Astronomy, University of Turku, FI-20014 Turun yliopisto, Finland 2Dipartimento di Fisica, Università degli Studi di Trieste, I-34151 Trieste, Italy 3CNISM, Unitá di Ricerca di Milano Università, I-20133 Milano, Italy 4Dipartimento di Fisica...

Qian Liu: Non-parametric machine learning methods for clustering and variable selection (Under the direction of Eric Bair) Non-parametric machine learning methods have been popular and widely used in many scientific research areas, especially when dealing with high-dimension low sample size (HDLSS) data. In particular, clustering and biclustering approaches can serve as exploratory analysis too...

Context. The observation of rapidly variable very high energy (VHE) gamma-rays from non-aligned active galactic nuclei (AGNs), as reported from M87, proves challenging for conventional theoretical acceleration and emission models. Aims. Motivated by recent work on pulsar-type particle acceleration in M87 (Neronov & Aharonian 2007), we re-examine the centrifugal acceleration of particles by rota...

in the present work, a hybrid of fourier transform and homotopy perturbation method is developed for solving the non-homogeneous partial differential equations with variable coefficients. the fourier transform is employed with combination of homotopy perturbation method (hpm), the so called fourier transform homotopy perturbation method (fthpm) to solve the partial differential equations. the c...

‎This paper considers a non-local initial-boundary value problem containing a first order partial differential equation with variable coefficients‎. ‎At first‎, ‎the non-self-adjoint spectral problem is derived‎. ‎Then its adjoint problem is calculated‎. ‎After that‎, ‎for the adjoint problem the associated eigenvalues and the subsequent eigenfunctions are determined‎. ‎Finally the convergence ...