Search results for "Compres"
showing 10 items of 1107 documents
Data Compression with ENO Schemes: A Case Study
2001
Abstract We study the compresion properties of ENO-type nonlinear multiresolution transformations on digital images. Specific error control algorithms are used to ensure a prescribed accuracy. The numerical results reveal that these methods strongly outperform the more classical wavelet decompositions in the case of piecewise smooth geometric images.
Signal Denoising with Harten’s Multiresolution Using Interpolation and Least Squares Fitting
2014
Harten’s multiresolution has been successfully applied to the signal compression using interpolatory reconstructions with nonlinear techniques. Here we study the applicability of these techniques to remove noise to piecewise smooth signals. We use two reconstruction types: interpolatory and least squares, and we introduce ENO and SR nonlinear techniques. The standard methods adaptation to noisy signals and the comparative of the different schemes are the subject of this paper.
Visual information flow in Wilson-Cowan networks.
2020
In this paper, we study the communication efficiency of a psychophysically tuned cascade of Wilson-Cowan and divisive normalization layers that simulate the retina-V1 pathway. This is the first analysis of Wilson-Cowan networks in terms of multivariate total correlation. The parameters of the cortical model have been derived through the relation between the steady state of the Wilson-Cowan model and the divisive normalization model. The communication efficiency has been analyzed in two ways: First, we provide an analytical expression for the reduction of the total correlation among the responses of a V1-like population after the application of the Wilson-Cowan interaction. Second, we empiri…
Testing the effects of pre-processing on voxel based morphometry analysis
2015
Voxel based morphometry (VBM) is an automated analysis technique which allows voxel-wise comparison of mainly grey-matter volumes between two magnetic resonance images (MRI). Two main analysis processes in VBM are possible. One is cross-sectional data analysis, where one group is compared with another to depict see the regions in the brain, which show changes in their grey-matter volume. Second is longitudinal data analysis, where MRIs, taken at different time points, are compared to see the regions in the brain that show changes in their grey matter volume for one time point with respect to another time point. Both types of analyses require pre-processing steps before performing the statis…
Detector-electrode for alpha spectrometry in water sample, numerical and early feasibility investigation toward thermocompression bonding assembly pr…
2020
International audience; This study focuses on the feasibility of a detector-electrode for direct alpha measurement in aqueous samples. Such a device could be made by adding a boron doped diamond electrode on top of a standard silicon detector, with bonding and insulating layers. The impact of these different layers has been investigated by Monte-Carlo simulation (MCNP6), to find a compromise between alpha detection of the silicon, electrode and shielding properties of the diamond. The assembly process involving thermocompression between both substrates was successfully achieved under a clean room conditions.
Can one ever prove that neutrinos are Dirac particles?
2017
According to the "Black Box" theorem the experimental confirmation of neutrinoless double beta decay ($0 \nu 2 \beta$) would imply that at least one of the neutrinos is a Majorana particle. However, a null $0 \nu 2 \beta$ signal cannot decide the nature of neutrinos, as it can be suppressed even for Majorana neutrinos. In this letter we argue that if the null $0 \nu 2 \beta$ decay signal is accompanied by a $0 \nu 4 \beta$ quadruple beta decay signal, then at least one neutrino should be a Dirac particle. This argument holds irrespective of the underlying processes leading to such decays.
What can we learn from neutrinoless double beta decay experiments?
2004
We assess how well next generation neutrinoless double beta decay and normal neutrino beta decay experiments can answer four fundamental questions. 1) If neutrinoless double beta decay searches do not detect a signal, and if the spectrum is known to be inverted hierarchy, can we conclude that neutrinos are Dirac particles? 2) If neutrinoless double beta decay searches are negative and a next generation ordinary beta decay experiment detects the neutrino mass scale, can we conclude that neutrinos are Dirac particles? 3) If neutrinoless double beta decay is observed with a large neutrino mass element, what is the total mass in neutrinos? 4) If neutrinoless double beta decay is observed but ne…
Hydraulic assessment of an upgraded pipework arrangement for the DEMO divertor plasma facing components cooling circuit
2021
Abstract In the context of the Work Package DIVertor (WPDIV) of the EUROfusion action, a research campaign has been carried out by University of Palermo in cooperation with ENEA to assess the thermal-hydraulic performances of the DEMO divertor cooling system, concentrating the attention on its 2019 Plasma Facing Components (PFCs) configuration, relevant to DEMO baseline 2017. The research activity has been performed following a theoretical-numerical technique based on the finite volume method and adopting the well-known ANSYS CFX CFD code. The PFCs cooling circuit thermal-hydraulic performances under nominal steady-state conditions, assessed mainly in terms of coolant total pressure drop, c…
P5285Pressure-volume relationship by cardiovascular magnetic resonance: feasibility and clinical implications
2019
Abstract Background The variation between rest and peak stress end-systolic pressure-volume relation (ESPVR; the Suga index) is easily obtained during routine stress echocardiography and has been established as a reasonably load-independent index of myocardial contractile performance that provides prognostic information above and beyond regional wall motion. Purpose This is the first study assessing the delta rest-stress ESPVR (DESPVR) by stress Cardiovascular Magnetic Resonance (CMR). Methods Eighty-five consecutive patients (19 females, main age 62.99±9.26 years) who underwent dipyridamole stress-CMR in a high volume CMR Laboratory were considered. The ESPVR was evaluated at rest and peak…
Convergence of a finite volume scheme for the compressible Navier–Stokes system
2019
We study convergence of a finite volume scheme for the compressible (barotropic) Navier–Stokes system. First we prove the energy stability and consistency of the scheme and show that the numerical solutions generate a dissipative measure-valued solution of the system. Then by the dissipative measure-valued-strong uniqueness principle, we conclude the convergence of the numerical solution to the strong solution as long as the latter exists. Numerical experiments for standard benchmark tests support our theoretical results.