Search results for "Linear"
showing 10 items of 7165 documents
Stochastic response determination of nonlinear oscillators with fractional derivatives elements via the Wiener path integral
2014
A novel approximate analytical technique for determining the non-stationary response probability density function (PDF) of randomly excited linear and nonlinear oscillators endowed with fractional derivatives elements is developed. Specifically, the concept of the Wiener path integral in conjunction with a variational formulation is utilized to derive an approximate closed form solution for the system response non-stationary PDF. Notably, the determination of the non-stationary response PDF is accomplished without the need to advance the solution in short time steps as it is required by the existing alternative numerical path integral solution schemes which rely on a discrete version of the…
A New Time Dependent Model Based on Level Set Motion for Nonlinear Deblurring and Noise Removal
1999
In this paper we summarize the main features of a new time dependent model to approximate the solution to the nonlinear total variation optimization problem for deblurring and noise removal introduced by Rudin, Osher and Fatemi. Our model is based on level set motion whose steady state is quickly reached by means of an explicit procedure based on an ENO Hamilton-Jacobi version of Roe's scheme. We show numerical evidence of the speed, resolution and stability of this simple explicit procedure in two representative 1D and 2D numerical examples.
Baltijos šalių socialinio klimato suvokimas: metodologija ir palyginamumas
2017
Social climate is a relatively new concept measuring people’s wellbeing (Duguleană and Duguleană 2015), operationalized by perceptions of people’s conditions of living. It has been used in the Eurobarometer surveys since 2009 but still gained little attention in academic research. In this paper, issues in constructing an index of social climate are being discussed. As the rates of meaningful responses to questions on different aspects of the social climate vary greatly, the author proposes a revisited version of the social climate index as well as assesses its internal consistency and usability. The article presents the results of the regression analysis on the impact of factors related to …
Evanescent wave approximation for non-Hermitian Hamiltonians
2020
The counterpart of the rotating wave approximation for non-Hermitian Hamiltonians is considered, which allows for the derivation of a suitable effective Hamiltonian for systems with some states undergoing decay. In the limit of very high decay rates, on the basis of this effective description we can predict the occurrence of a quantum Zeno dynamics, which is interpreted as the removal of some coupling terms and the vanishing of an operatorial pseudo-Lamb shift.
Optical Dark Rogue Wave
2016
AbstractPhotonics enables to develop simple lab experiments that mimic water rogue wave generation phenomena, as well as relativistic gravitational effects such as event horizons, gravitational lensing and Hawking radiation. The basis for analog gravity experiments is light propagation through an effective moving medium obtained via the nonlinear response of the material. So far, analogue gravity kinematics was reproduced in scalar optical wave propagation test models. Multimode and spatiotemporal nonlinear interactions exhibit a rich spectrum of excitations, which may substantially expand the range of rogue wave phenomena and lead to novel space-time analogies, for example with multi-parti…
INTERFACE TENSION AND CORRELATION LENGTH OF 2D POTTS MODELS: NUMERICAL VERSUS EXACT RESULTS
1994
I briefly review new analytical formulas for the correlation length and interface tension of two-dimensional q-state Potts models and compare them with numerical results from recent Monte Carlo simulation studies.
Estimating COVID-19-induced Excess Mortality in Lombardy
2021
AbstractWe compare the expected all-cause mortality with the observed one for different age classes during the pandemic in Lombardy, which was the epicenter of the epidemic in Italy and still is the region most affected by the pandemic. A generalized linear mixed model is introduced to model weekly mortality from 2011 to 2019, taking into account seasonal patterns and year-specific trends. Based on the 2019 year-specific conditional best linear unbiased predictions, a significant excess of mortality is estimated in 2020, leading to approximately 35000 more deaths than expected, mainly arising during the first wave. In 2021, instead, the excess mortality is not significantly different from z…
Concurrent and lagged effects of counterdispositional extraversion on vitality
2020
Abstract There are two contrasting perspectives on the effects of state extraversion. One states that people benefit from behaving extraverted, regardless of their level of trait extraversion. The second entails that behaving concordant to one’s trait is natural while deviations from the trait level— counterdispositional behaviors—are effortful to maintain, leading to mental fatigue. We test the possibility that both perspectives are correct, with beneficial effects of high state extraversion showing immediately, while the depleting counterdispositional effects are delayed. Experience sampling data from 67 employees (N = 1,664), shows that extraverted behaviors are associated with high leve…
Extraversion and performance approach goal orientation : An integrative approach to personality
2019
Abstract Research shows that extraversion is unrelated to performance approach goal orientation, both at the trait- and the state-level. However, since previous studies have either focused on the trait- or the state-level, such a conclusion may be premature. Building upon the idea that acting against one’s trait consumes self-control resources, we reason that within-person deviations from one’s level of trait extraversion might negatively relate to performance approach goal orientation. Using experience sampling data from 47 employees across 10 days (N = 307), we found that deviations from one’s trait extraversion levels are associated with lower levels of performance approach goal orientat…
Experimental characterization and comparison of TLIM performances with different primary winding connections
2017
Abstract This paper presents an experimental characterization and comparison of the performances achieved by a Tubular Linear Induction Motor (TLIM) prototype with different typologies of primary winding connections. More in detail, three different configurations have been considered, analyzed and discussed: full-pitch star, 5/6 shortened pitch star and 5/6 shortened pitch double star. For this purpose, an experimental test bench at the Sustainable Development and Energy Saving Laboratory (SDESLab), University of Palermo, Italy, has been set-up. The obtained results have allowed the identification of the best winding configuration for different applications intended for the motor. Moreover,…