Search results for "NOISE"
showing 10 items of 1375 documents
Upper limits on the isotropic gravitational-wave background from Advanced LIGO and Advanced Virgo's third observing run
2021
We report results of a search for an isotropic gravitational-wave background (GWB) using data from Advanced LIGO's and Advanced Virgo's third observing run (O3) combined with upper limits from the earlier O1 and O2 runs. Unlike in previous observing runs in the advanced detector era, we include Virgo in the search for the GWB. The results are consistent with uncorrelated noise, and therefore we place upper limits on the strength of the GWB. We find that the dimensionless energy density $\Omega_{\rm GW}\leq 5.8\times 10^{-9}$ at the 95% credible level for a flat (frequency-independent) GWB, using a prior which is uniform in the log of the strength of the GWB, with 99% of the sensitivity comi…
Le bruit en milieu urbain : bruit et scolarité à Besançon
2009
The Spike Noise Based on the Renewal Point Process and Its Possible Applications
2010
We consider a non-Markovian random process in the form of spikes train, where the time intervals between neighboring delta-pulses are mutually independent and identically distributed, i.e. represent the renewal process (1967). This noise can be interpreted as the derivative of well-known continuous time random walk (CTRW) model process with fixed value of jumps. The closed set of equations for the characteristic functional of the noise, useful to split the correlations between stochastic functionals (2008), is obtained. In the particular case of Poisson statistics these equations can be exactly solved and the expression for the characteristic functional coincides with the result for shot no…
Modeling long-range memory with stationary Markovian processes
2009
In this paper we give explicit examples of power-law correlated stationary Markovian processes y(t) where the stationary pdf shows tails which are gaussian or exponential. These processes are obtained by simply performing a coordinate transformation of a specific power-law correlated additive process x(t), already known in the literature, whose pdf shows power-law tails 1/x^a. We give analytical and numerical evidence that although the new processes (i) are Markovian and (ii) have gaussian or exponential tails their autocorrelation function still shows a power-law decay =1/T^b where b grows with a with a law which is compatible with b=a/2-c, where c is a numerical constant. When a<2(1+c) th…
Le repas d'affaires
2007
Temporal Denoising of Kinect Depth Data
2012
The release of the Microsoft Kinect has attracted the attention of researchers in a variety of computer science domains. Even though this device is still relatively new, its recent applications have shown some promising results in terms of replacing current conventional methods like the stereo-camera for robotics navigation, multi-camera system for motion detection and laser scanner for 3D reconstruction. While most work around the Kinect is on how to take full advantage of its capabilities, so far only a few studies have been carried out on the limitations of this device and fewer that provide solutions to enhance the precision of its measurements. In this paper, we review and analyse curr…
AQUATIC ACOUSTIC NOISE: BEHAVIORAL AND MOLECULAR RESPONSES IN ECHINODERMS, THE CASE OF A. LIXULA (LINNAEUS, 1758) SEA URCHINS
2018
Anthropic noise is considered a real pollutant, in particular the submarine noise. The impact on biodiversity is not yet sufficiently understood. Further research is needed to evaluate any negative effects. The noises associated with anthropogenic activities are increasing: shipments, seismic surveys, sonar, recreational rowing and future mineral extraction activities from ocean depths (DSM). These noises are having an impact on the welfare of many marine species. The understanding of the effects on biodiversity could be important for the creation of guidelines, laws or rules for the most environmentally sustainable exploitation of natural resources. Our study aims to investigate the motili…
Effects of waterg gun on echinoderms: biochemical changes on sea urchin (Arbacia lixula) and sea cucumber (Holothuria tubulosa)
2019
Sources Airguns and Waterguns are used in seismic exploration the marine seafloor for different purposes such as oil and gas search, or geological-geodynamic reconstruction. In this technique a bubble of compressed air is produced with a consequently production of loud sound wave penetrating the ocean floor. The impact of seismic Airguns was assessed in some cetaceans (Kyhn et al. 2019), fish species and invertebrate (Carroll et al. 2017), but we need to know more. In this study we evaluate the biochemical changes in sea urchin (Arbacia lixula) and sea cucumber (Holothuria tubulosa) exposed to a 20 minutes of watergun noise (1 pulse each 10 s) at a distance of 50 m. For each species 40 indi…
Squeezing of Quantum Noise of Motion in a Micromechanical Resonator
2015
A pair of conjugate observables, such as the quadrature amplitudes of harmonic motion, have fundamental fluctuations which are bound by the Heisenberg uncertainty relation. However, in a squeezed quantum state, fluctuations of a quantity can be reduced below the standard quantum limit, at the cost of increased fluctuations of the conjugate variable. Here we prepare a nearly macroscopic moving body, realized as a micromechanical resonator, in a squeezed quantum state. We obtain squeezing of one quadrature amplitude $1.1 \pm 0.4$ dB below the standard quantum limit, thus achieving a long-standing goal of obtaining motional squeezing in a macroscopic object.
Discrete cortical representations and their stability in the presence of synaptic turnover
2015
Population imaging in mouse auditory cortex revealed clustering of neural responses to brief complex sounds: the activity of a local population typically falls close to one out of a small number of observed states [1]. These clusters appear to group sets of auditory stimuli into a discrete set of activity patterns and could thereby form the basis for representations of sound categories. However, to be useful for the brain, such representations should be robust against fluctuations in the underlying circuitry, which are significant even in the absences of any explicit learning paradigm [2]. Here we introduce a novel firing rate based circuit model of mouse auditory cortex to study the emerge…