Search results for " propagation"
showing 10 items of 488 documents
The dynamics of a developing CW supercontinuum: Analytical predictions and experiments
2010
International audience; We show that the development of the supercontinuum spectrum in the quasi-CW regime can be interpreted analytically in terms of Akhmediev Breathers. Theory and experiment are in excellent agreement.
An Improved Receiver Architecture for Cyclic-Prefixed OFDM
2009
A novel Orthogonal Frequency Division Multiplexing receiver architecture to be employed with standard (e.g. Wireless LAN) transmitters is proposed. It features enhanced error-rate performance with flexible computational complexity and robustness to imperfect channel estimation. It is based on exploitation of the redundancy available in the cyclic prefix after cancellation of interference from the previous block. In order to show the effectiveness of our proposal, a number of comparisons to the standard per-subcarrier receiver and a previously existing method are reported.
On the propagation of a perturbation in an anharmonic system
2007
We give a not trivial upper bound on the velocity of disturbances in an infinitely extended anharmonic system at thermal equilibrium. The proof is achieved by combining a control on the non equilibrium dynamics with an explicit use of the state invariance with respect to the time evolution.
Functional Brain Segmentation Using Inter-Subject Correlation in fMRI
2016
The human brain continuously processes massive amounts of rich sensory information. To better understand such highly complex brain processes, modern neuroimaging studies are increasingly utilizing experimental setups that better mimic daily‐life situations. A new exploratory data‐analysis approach, functional segmentation inter‐subject correlation analysis (FuSeISC), was proposed to facilitate the analysis of functional magnetic resonance (fMRI) data sets collected in these experiments. The method provides a new type of functional segmentation of brain areas, not only characterizing areas that display similar processing across subjects but also areas in which processing across subjects is h…
Blind Radio Tomography
2018
From the attenuation measurements collected by a network of spatially distributed sensors, radio tomography constructs spatial loss fields (SLFs) that quantify absorption of radiofrequency waves at each location. These SLFs can be used for interference prediction in (possibly cognitive) wireless communication networks, for environmental monitoring or intrusion detection in surveillance applications, for through-the-wall imaging, for survivor localization after earthquakes or fires, etc. The cornerstone of radio tomography is to model attenuation as the bidimensional integral of the SLF of interest scaled by a weight function. Unfortunately, existing approaches (i) rely on heuristic assumpti…
Increasing the performance of HSDPA with high-speed single frequency network
2012
High Speed Single Frequency Network (HS-SFN) is a multi-cell transmission scheme for High-Speed Downlink Packet Access (HSDPA) that can assist user equipment (UEs) in the softer handover area by combining signals from two neighbouring cells and at the same time by reducing the inter-cell interference. This article analyzes performance of HS-SFN for macro cell scenario under different channels with different type of schedulers by means of extensive system level simulations. The results indicate that HS-SFN can increase throughput for UEs in softer handover area from 40% to 80% without decreasing the overall performance.
Modeling of neuron-astrocyte interaction : application to signal and image processing
2022
The introduction of the tripartite synapse and the discovery of calcium wave propagation motivated our research to explore the potential of astrocytes as active components in brain circuits. For decades, astrocytes have been considered passive cells whose primary function is metabolic and structural support to neurons; however, recent physiological measurements suggest that astrocytes modulate neural communication, strengthen synaptic efficacy, enhance synchronization, and promote homeostasis. Inspired by these biological functions, this research aimed to implement astrocytes in artificial spiking networks for deep learning applications. First, we modeled the biological interaction between …
A free plate model can predict guided modes propagating in tubular bone-mimicking phantoms
2014
The goal of this work was to show that a non-absorbing free plate model can predict with a reasonable accuracy guided modes measured in bone-mimicking phantoms that have circular cross-section. Experiments were carried out on uncoated and coated phantoms using a clinical axial transmission setup. Adjustment of the plate model to the experimental data yielded estimates for the waveguide characteristics (thickness, bulk wave velocities). Fair agreement was achieved over a frequency range of 0.4 to 1.6 MHz. A lower accuracy observed for the thinnest bone-mimicking phantoms was caused by limitations in the wave number measurements rather than by the model itself.
A computational framework for coating fatigue analysis of wind turbine blades due to rain erosion
2021
Author's accepted manuscript The rain-induced fatigue damage in the wind turbine blade coating has attracted increasing attention owing to significant repair and maintenance costs. The present paper develops an improved computational framework for analyzing the wind turbine blade coating fatigue induced by rain erosion. The paper first presents an extended stochastic rain field simulation model that considers different raindrop shapes (spherical, flat, and spindle), raindrop sizes, impact angles, and impact speeds. The influence of these raindrop characteristics on the impact stress of the blade coating is investigated by a smoothed particle hydrodynamics approach. To address the expensive …
Simulation of the Propagation of Tsunamis in Coastal Regions by a Two-Dimensional Non-Hydrostatic Shallow Water Solver
2017
Due to the enormous damages and losses of human lives in the inundated regions, the simulation of the propagation of tsunamis in coastal areas has received an increasing interest of the researchers. We present a 2D depth-integrated, non- hydrostatic shallow waters solver to simulate the propagation of tsunamis, solitary waves and surges in coastal regions. We write the governing continuity and momentum equations in conservative form and discretize the domain with unstructured triangular Generalized Delaunay meshes. We apply a fractional- time-step procedure, where two problems (steps) are consecutively solved. In the first and in the second step, we hypothesize a hydrostatic and a non-hydro…