Search results for "Distortion"
showing 10 items of 309 documents
Mappings of finite distortion : size of the branch set
2018
Abstract We study the branch set of a mapping between subsets of ℝ n {\mathbb{R}^{n}} , i.e., the set where a given mapping is not defining a local homeomorphism. We construct several sharp examples showing that the branch set or its image can have positive measure.
Conformal measures for multidimensional piecewise invertible maps
2001
Given a piecewise invertible map T:X\to X and a weight g:X\rightarrow\ ]0,\infty[ , a conformal measure \nu is a probability measure on X such that, for all measurable A\subset X with T:A\to TA invertible, \nu(TA)= \lambda \int_{A}\frac{1}{g}\ d\nu with a constant \lambda>0 . Such a measure is an essential tool for the study of equilibrium states. Assuming that the topological pressure of the boundary is small, that \log g has bounded distortion and an irreducibility condition, we build such a conformal measure.
Mappings of finite distortion: Capacity and modulus inequalities
2006
We establish capacity and modulus inequalities for mappings of finite distortion under minimal regularity assumptions.
Demand Sharing Inaccuracies in Supply Chains: A Simulation Study
2018
We investigate two main sources of information inaccuracies (i.e., errors and delays) in demand information sharing along the supply chain (SC). Firstly, we perform a systematic literature review on inaccuracy in demand information sharing and its impact on supply chain dynamics. Secondly, we model several SC settings using system dynamics and assess the impact of such information inaccuracies on SC performance. More specifically, we study the impact of four factors (i.e., demand error, demand delay, demand variability, and average lead times) using three SC dynamic performance indicators (i.e., bullwhip effect, inventory variability, and average inventory). The results suggest that demand …
OmniFlowNet: a Perspective Neural Network Adaptation for Optical Flow Estimation in Omnidirectional Images
2021
International audience; Spherical cameras and the latest image processing techniques open up new horizons. In particular, methods based on Convolutional Neural Networks (CNNs) now give excellent results for optical flow estimation on perspective images. However, these approaches are highly dependent on their architectures and training datasets. This paper proposes to benefit from years of improvement in perspective images optical flow estimation and to apply it to omnidirectional ones without training on new datasets. Our network, OmniFlowNet, is built on a CNN specialized in perspective images. Its convolution operation is adapted to be consistent with the equirectangular projection. Teste…
Coupled dark matter-dark energy in light of near Universe observations
2010
Cosmological analysis based on currently available observations are unable to rule out a sizeable coupling among the dark energy and dark matter fluids. We explore a variety of coupled dark matter-dark energy models, which satisfy cosmic microwave background constraints, in light of low redshift and near universe observations. We illustrate the phenomenology of different classes of dark coupling models, paying particular attention in distinguishing between effects that appear only on the expansion history and those that appear in the growth of structure. We find that while a broad class of dark coupling models are effectively models where general relativity (GR) is modified - and thus can b…
Doppler Estimation and Correction for JANUS Underwater Communications
2020
In recent years, underwater communications have seen a growing interest pushed by marine research, oceanography, marine commercial operations, offshore oil industry and defense applications. Generally, underwater communications employ audio signals which can propagate relatively far but are also significantly affected by Doppler distortions. In fact, physical properties of the water and spatial changes due to tides, currents and waves can cause channel variations or unwanted movements of the transmitter or receiver. This study shows how to compensate for the Doppler effect in transmission employing the JANUS standard, a popular modulation scheme for underwater communication. Differently for…
Experimental Evaluation of the Performance of a Three-Phase Five-Level Cascaded H-Bridge Inverter by Means FPGA-Based Control Board for Grid Connecte…
2018
Over the last decades, plants devoted to the generation of green energy significantly increased their number, together with the demand of same electrical energy, also stored in battery systems. This fact produced the growth of energy conversion systems with advanced performances with respect to the traditional ones. In this circumstance, multilevel converters play a significant role for their great advantages in performances, flexibility, fault-tolerability, employment of renewable energy sources and storage systems and finally yet importantly reduced filter requirements. In this context, this paper faces the performance of a cascaded H-bridge 5 level inverter in terms of harmonic distortio…
A 9-level three-phase multilevel converter with harmonic mitigation and integrated battery balancing
2019
In this paper, a 9 level three-phase multilevel converter with a harmonic mitigation control method and an integrated battery balancing algorithm for automotive purpose is proposed. Each level of the converter is composed by a buck-boost converter and an h-bridge in cascaded connection. The control algorithm is implemented to achieve the harmonic mitigation on the output voltage waveform and to maintain the battery input voltages balanced. The design and operation of the system is described, and simulation study is reported using Matlab/Simulink platform.
Octahedral distortion caused by hydrogen bonding in tris(diethylammonium) hexachloridoantimonate(III).
2010
The factors influencing the distortion of inorganic anions in the structures of chloridoantimonates(III) with organic cations, in spite of numerous structural studies on those compounds, have not been clearly described and separated. The title compound, [(C(2)H(5))(2)NH(2)](3)[SbCl(6)], consisting of isolated distorted [SbCl(6)](3-) octahedra that have C(3) symmetry and [(C(2)H(5))(2)NH(2)](+) cations, unequivocally shows the role played by hydrogen bonding in the geometry variations of inorganic anions. The organic cations, which are linked to the inorganic substructure through N-H...Cl hydrogen bonds, are clearly responsible for the distortion of the octahedral coordination of Sb(III) in …