Search results for "NETWORKS"
showing 10 items of 3260 documents
Shape coexistence in Hg-178
2019
Lifetime measurements of excited states in Hg-178 have been performed using the Rh-103(Kr-78, p2n) reaction at a beam energy of 354 MeV. The recoil-decay tagging (RDT) technique was applied to select the Hg-178 nuclei and associate the prompt gamma rays with the correlated characteristic ground-state alpha decay. Lifetimes of the four lowest yrast states of Hg-178 have been determined using the recoil distance Doppler-shift (RDDS) method. The experimental data are compared to theoretical predictions with focus on shape coexistence. The results confirm the shift of the deformed prolate structures to higher lying states but also indicate their increasing deformation with decreasing neutron nu…
Aging effects manifested in the potential-energy landscape of a model glass former
2010
We present molecular dynamics simulations of a model glass-forming liquid (the binary Kob-Anderson Lennard-Jones model) and consider the distributions of inherent energies and metabasins during aging. In addition to the typical protocol of performing a temperature jump from a high temperature to a low destination temperature, we consider the temporal evolution of the distributions after an 'up-jump', i.e. from a low to a high temperature. In this case the distribution of megabasin energies exhibits a transient two-peak structure. Our results can qualitatively be rationalized in terms of a trap model with a Gaussian distribution of trap energies. The analysis is performed for different syste…
Functional and local renormalization groups
2015
We discuss the relation between functional renormalization group (FRG) and local renormalization group (LRG), focussing on the two dimensional case as an example. We show that away from criticality the Wess-Zumino action is described by a derivative expansion with coefficients naturally related to RG quantities. We then demonstrate that the Weyl consistency conditions derived in the LRG approach are equivalent to the RG equation for the $c$-function available in the FRG scheme. This allows us to give an explicit FRG representation of the Zamolodchikov-Osborn metric, which in principle can be used for computations.
A principal component analysis based method for the Simulation of turbulence-degraded infrared image sequence
1999
Une methode originale de simulation d’images degradees par la turbulence atmospherique est presentee. Les methodes existantes ne permettent de simuler que des images temporellement decorrelees les unes des autres, dans le cas de l ’isoplanetisme ou du faible anisoplanetisme. Dans cet article, une simulation pour le cas de fort anisoplanetisme est proposee et une etude sur l’aspect temporel du phenomene dans le but de construire une sequence d’images degradees, a l’aide de l’analyse en composantes principales est faite. Les images obtenues montrent clairement les effets de lanisoplanetisme et l’evolution temporelle de la turbulence.
High-frequency vibrational density of states of a disordered solid.
2013
We investigate the high-frequency behavior of the density of vibrational states in three-dimensional elasticity theory with spatially fluctuating elastic moduli. At frequencies well above the mobility edge, instanton solutions yield an exponentially decaying density of states. The instanton solutions describe excitations, which become localized due to the disorder-induced fluctuations, which lower the sound velocity in a finite region compared to its average value. The exponentially decaying density of states (known in electronic systems as the Lifshitz tail) is governed by the statistics of a fluctuating-elasticity landscape, capable of trapping the vibrational excitations.
Fluctuations in mesoscopic systems
1992
Abstract Electronic wavefunctions in weakly disordered systems have been studied within the Anderson model of localization. The eigenstates calculated by means of the Lanczos diagonalization algorithm display characteristic spatial fluctuations that can be described by a multifractal analysis. For increasing disorder or energy the observed curdling of the wavefunction reflects the stronger localization, but no exponential decay can be observed. This is reflected in the set of generalized fractal dimensions and the singularity spectrum of the fractal measure.
Noise enhanced stability in magnetic systems
2009
In this paper noise enhanced stability in magnetic systems is studied by both an Ising-type model and a Preisach–Arrhenius model as well as a dynamic Preisach model. It is shown that in one nonequilibrium Ising system noise enhanced stability occurs and that dynamic Preisach model has the capability to predict the occurrence of noise enhanced stability in magnetic systems. On the contrary, in a Preisach–Arrhenius model of a single quadrant magnetic material, noise enhanced stability is not detected.
Lifetime measurements in 166Re : Collective versus magnetic rotation
2016
WOS: 000371740600004
Improved Neural Networks with Random Weights for Short-Term Load Forecasting.
2015
An effective forecasting model for short-term load plays a significant role in promoting the management efficiency of an electric power system. This paper proposes a new forecasting model based on the improved neural networks with random weights (INNRW). The key is to introduce a weighting technique to the inputs of the model and use a novel neural network to forecast the daily maximum load. Eight factors are selected as the inputs. A mutual information weighting algorithm is then used to allocate different weights to the inputs. The neural networks with random weights and kernels (KNNRW) is applied to approximate the nonlinear function between the selected inputs and the daily maximum load…
Approches région et bayésienne pour la restauration ďimages dégradées par la turbulence atmosphérique
2001
La turbulence atmospherique perturbe ľobservation a haute resolution. C’est un phenomene etudie depuis longtemps, en astronomie notamment. Le present article porte sur le cas de ľobservation ďun objet situe environ vingt kilometres, la propagation etant horizontale et pres du sol, en infrarouge. Les images a longue pose sont restaurees avec des algorithmes classiques de deconvolution. Les resultats ne sont satisfaisants que pour une faible perturbation. Il est plus avantageux ďexploiter des images courte pose, car elles contiennent plus de hautes frequences spatiales; mais ľobjet observe y fluctue aleatoirement. On travaille donc ici partir ďune sequence de plusieurs dizaines ďimages. Deux …