Search results for "extrapolation"

Slender Ca II H fibrils mapping magnetic fields in the low solar chromosphere

2017

S. Jafarzadeh et. al.

Reciprocal extrapolation of species distribution models between two islands – Specialists perform better than generalists and geological data reduces…

2020

Abstract This study aims to test the extrapolation effects of species distribution models (SDM) using three groups of predictor variables: climate, relief and geology (bedrock type). We highlight potential ecological differences for selected taxa, regarding both generalists and specialists in terms of edaphic conditions. We used distributional data of 12 woody species shared by two large Mediterranean islands (Crete and Sicily) to calibrate Maxent models of their potential distribution. We trained models with data from Crete and extrapolated to Sicily and vice versa. We tested ten proxies for the three variable groups and compared AUC values as a measure of model performance. Extrapolation …

Modified F-transform Based on B-splines

2018

The aim of this paper is to improve the F-transform technique based on B-splines. A modification of the F-transform of higher degree with respect to fuzzy partitions based on B-splines is done to extend the good approximation properties from the interval where the Ruspini condition is fulfilled to the whole interval under consideration. The effect of the proposed modification is characterized theoretically and illustrated numerically.

Accélération de la convergence et algorithme proximal

1995

Nous faisons une première étude de la question de savoir s'il est possible d'accélérer des suites issues de l'algorithme proximal ou de la méthode de l'inverse partiel par des méthodes d'extrapolation.

Finite-size scaling of charge carrier mobility in disordered organic semiconductors

2016

Simulations of charge transport in amorphous semiconductors are often performed in microscopically sized systems. As a result, charge carrier mobilities become system-size dependent. We propose a simple method for extrapolating a macroscopic, nondispersive mobility from the system-size dependence of a microscopic one. The method is validated against a temperature-based extrapolation [A. Lukyanov and D. Andrienko, Phys. Rev. B 82, 193202 (2010)]. In addition, we provide an analytic estimate of system sizes required to perform nondispersive charge transport simulations in systems with finite charge carrier density, derived from a truncated Gaussian distribution. This estimate is not limited t…

Adaptive rational interpolation for point values

2019

Abstract G. Ramponi et al. introduced in Carrato et al. (1997,1998), Castagno and Ramponi (1996) and Ramponi (1995) a non linear rational interpolator of order two. In this paper we extend this result to get order four. We observe the Gibbs phenomenon that is obtained near discontinuities with its weights. With the weights we propose we obtain approximations of order four in smooth regions and three near discontinuities. We also introduce a rational nonlinear extrapolation which is also of order four in the smooth region of the given function. In the experiments we calculate numerically approximation orders for the different methods described in this paper and see that they coincide with th…

2020

Abstract. An ice cloud chamber was developed at the Johannes Gutenberg University of Mainz for generating several thousand data points for mass and sedimentation velocity measurements of ice crystals with sizes less than 150 µm. Ice nucleation was initiated from a cloud of supercooled droplets by local cooling using a liquid nitrogen cold finger. Three-dimensional tracks of ice crystals falling through the slightly supersaturated environment were obtained from the reconstruction of sequential holographic images, automated detection of the crystals in the hologram reconstructions, and particle tracking. Through collection of the crystals and investigation under a microscope before and after …

Causality and the Coulomb sum rule in nuclei.

1989

The spectral function in the Jost-Lehmann-Dyson representation of causal commutators is determined for the nonrelativistic limit of inclusive lepton scattering from nuclei. From this an extrapolation of the Coulomb sum rule to higher-momentum transfers is performed which is consistent with the requirement of causality.

A semi-empirical extrapolation technique for atomic and molecular properties derived from correlated wavefunctions

1976

Abstract A semi-empirical extrapolation technique is suggested for recovering the correlation defect remaining in atomic and molecular properties calculated from highly correlated wavefunctions. These procedures are applied to PNO-CEPA and PNO-IPPA calculations on F, F + , F − , and HF in order to obtain “exact” estimates of the ionization potential, electron affinity, and dissociation energy.

An Optimization Device for Series Parallel Connected PV Plants

2017

In this paper it is presented a testing prototype of a reconfiguration system for photovoltaic (PV) plants. The system enables to increase the total energy output by reducing the electrical mismatch between the PV array modules. The architecture of the implemented switching matrix, performing the dynamic electrical interconnections of the PV panels, enables to reconfigure nine solar modules in a series-parallel (SP) configuration. The contribution is organized as follows. A brief state of the art is first presented, followed by a comparison between the SP and Total-Cross-Tied (TCT) connections. The prototype then is thoroughly described as well as the main design choices. Finally some tests…