Search results for "Nonlinear"

EMI Filter Re-Design in a SMPS with Inductor in Saturation

2021

This paper analyzes the design issues of the input EMI (Electro-Magnetic Interference) filter's in a switching mode power supply where the power inductor is operated in saturation. Starting with a SMPS equipped with linear inductor, the input filter is firstly designed to comply with Standards. Then, a new inductor with a smaller core size is employed in the same SMPS to exploit saturation. The EMI filter is re-designed, taking into account the increase of EMI introduced by the non-linear operation of the inductor. Finally, the reduction of the inductor's size and cost is compared with the increased size and cost of the EMI filter.

Non-volatile memory characteristics of a Ti/HfO2/Pt synaptic device with a crossbar array structure

2022

The resistive switching and synaptic behavior of a fabricated Ti/HfO2/Pt crossbar array device are investigated. The results demonstrated that TiOx layers are created by the movement of oxygen ions during the positive SET process, thereby improving the endurance and multilevel switching behavior of the device. The random properties of SET process were described with the help of stochastic model of memristor based on the length of conductive filament. The analysis of the mean first passage time allows estimating the parameters of the dielectric switching layer such as the activation energy of the diffusive defects, its variation under the influence of the driving voltage and the value of the…

Errors in Monte Carlo simulations using shift register random number generators

1996

We report large systematic errors in Monte Carlo simulations of the tricritical Blume-Capel model using single spin Metropolis updating. The error, manifest as a $20\%$ asymmetry in the magnetisation distribution, is traced to the interplay between strong triplet correlations in the shift register random number generator and the large tricritical clusters. The effect of these correlations is visible only when the system volume is a multiple of the random number generator lag parameter. No such effects are observed in related models.

THE INFLUENCE OF CONTRARIANS AND OPPORTUNISTS ON THE STABILITY OF A DEMOCRACY IN THE SZNAJD MODEL

2004

Sznajd-Weron and Sznajd introduced a model investigating the democratic development in a closed community. This model is based on the USDF-principle ("united we stand, divided we fall"). However, it faces the problem that the system tends either to a dictatorship (i.e., 100% pro or 100% contra) or to a stalemate state (i.e., exactly 50% pro, 50% contra). Based on their model, I will show that a democratic system keeps alive due to the existence of both opportunists and persons in opposition.

Parallel Computing for the study of the focusing Davey-Stewartson II equation in semiclassical limit

2012

The asymptotic description of the semiclassical limit of nonlinear Schrödinger equations is a major challenge with so far only scattered results in 1 + 1 dimensions. In this limit, solutions to the NLS equations can have zones of rapid modulated oscillations or blow up. We numerically study in this work the Davey-Stewartson system, a 2 + 1 dimensional nonlinear Schrödinger equation with a nonlocal term, by using parallel computing. This leads to the first results on the semiclassical limit for the Davey-Stewartson equations.

Counter-propagating frequency mixing with Terahertz waves in diamond

2013

Frequency conversion by means of Kerr nonlinearity is one of the most common and exploited nonlinear optical processes in the UV, visible, IR, and mid-IR spectral regions. Here we show that wave mixing of an optical field and a terahertz wave can be achieved in diamond, resulting in the frequency conversion of the terahertz radiation either by sum- or difference-frequency generation. In the latter case, we show that this process is phase matched and most efficient in a counterpropagating geometry.

ULTRA-BROADBAND COHERENT DETECTION OF TERAHERTZ PULSES VIA CMOS-COMPATIBLE SOLID-STATE DEVICES

Il presente lavoro di tesi presenta e dimostra una tecnica innovativa e completamente integrata dedita alla rilevazione coerente di radiazioni a frequenze Terahertz (THz), cioè di onde elettromagnetiche il cui contenuto frequenziale cade convenzionalmente nella finestra spettrale compresa tra 0.1-10x1012 Hz. Tale tecnica è stata battezzata col nome di solid-state-biased coherent detection (SSBCD), dal momento che essa sfrutta le proprietà di un mezzo a stato solido e consente di ricostruire simultaneamente l’informazione sulla fase e sull’ampiezza degli impulsi THz, anche nel caso in cui quest’ultimi siano dotati di spettri a banda cosiddetta “ultra larga” (> 10 THz). Tale metodo di rivelaz…

Preservice teachers implementing a nonlinear physical education pedagogy

2019

Background\ud In recent years, there has been considerable interest in the evolution of physical education teaching practice from a traditional teacher-centred approach to a student-centred approach. Consequently, research has focused on questions about the changing conceptions of the teaching and learning process, that is, from how ‘we’ teach to how ‘they’ learn. A contemporary theoretical model of the teaching and learning process could underpin learning design and delivery adopted in physical education. The constraints-led approach (CLA) is a viable alternative as its practice design and delivery is grounded in the contemporary motor learning theory of ecological dynamics within a nonlin…

High-precision mass measurement of $^{168}$Yb for verification of nonlinear isotope shift

2020

The absolute mass value of $^{168}$Yb has been directly determined with the JYFLTRAP Penning trap mass spectrometer at the Ion Guide Isotope Separator On-Line (IGISOL) facility. A more precise value of the mass of $^{168}$Yb is needed to extract possible signatures of beyond standard model physics from high-precision isotope shift measurements of Yb atomic transition frequencies. The measured mass-excess value, ME($^{168}$Yb) = $-$61579.846(94) keV, is 12 times more precise and deviates from the Atomic Mass Evaluation 2016 value by 1.7$\sigma$. The impact on precision isotope shift studies of the stable Yb isotopes is discussed.

Learning non-linear time-scales with kernel -filters

2009

A family of kernel methods, based on the @c-filter structure, is presented for non-linear system identification and time series prediction. The kernel trick allows us to develop the natural non-linear extension of the (linear) support vector machine (SVM) @c-filter [G. Camps-Valls, M. Martinez-Ramon, J.L. Rojo-Alvarez, E. Soria-Olivas, Robust @c-filter using support vector machines, Neurocomput. J. 62(12) (2004) 493-499.], but this approach yields a rigid system model without non-linear cross relation between time-scales. Several functional analysis properties allow us to develop a full, principled family of kernel @c-filters. The improved performance in several application examples suggest…