Search results for " NOISE"
showing 10 items of 659 documents
Urban structure changes and environmental factors of Valencian Community towns as potentital drivers of the House Sparrow decline
2021
El gorrión común Passer domesticus (Linnaeus, 1758) se encuentra en declive en gran parte de Europa. En España, destaca el caso de la Comunidad Valenciana, área de estudio de esta tesis, con descensos superiores al 95% en zonas rurales y al 70% en zonas urbanas. Las causas del declive en zonas urbanas no son claras. En los pueblos y ciudades de la Comunidad Valenciana se están produciendo importantes procesos de transformación de la estructura urbana que afectan a la disponibilidad y adecuación del hábitat para la especie. El objetivo de la tesis fue explorar esos cambios como potenciales impulsores del declive del gorrión común. La tesis se distribuye en 8 capítulos. El capítulo 1 contiene…
ean-Square Filtering for Polynomial System States Confused with Poisson Noises over Polynomial Observations
2011
Published version of an article in the journal: Modeling, Identification and Control. Also available from the publisher at: http://dx.doi.org/10.4173/mic.2011.2.1 In this paper, the mean-square filtering problem for polynomial system states confused with white Poisson noises over polynomial observations is studied proceeding from the general expression for the stochastic Ito differentials of the mean-square estimate and the error variance. In contrast to the previously obtained results, the paper deals with the general case of nonlinear polynomial states and observations with white Poisson noises. As a result, the Ito differentials for the mean-square estimate and error variance corre- spon…
Nonstationary response envelope probability densities of nonlinear oscillators
2006
The nonstationary random response of a class of lightly damped nonlinear oscillators subjected to Gaussian white noise is considered. An approximate analytical method for determining the response envelope statistics is presented. Within the framework of stochastic averaging, the procedure relies on the Markovian modeling of the response envelope process through the definition of an equivalent linear system with response-dependent parameters. An approximate solution of the associated Fokker-Planck equation is derived by resorting to a Galerkin scheme. Specifically, the nonstationary probability density function of the response envelope is expressed as the sum of a time-dependent Rayleigh dis…
Noise contribution to resonance phenomena and information propagation in non linear electronic networks
2015
This manuscript presents research aiming to show possible positive effects of deterministic and stochastic perturbations on the responses of different nonlinear systems. To that end, both numerical and experimental studies were carried out on two kinds of structures : an elementary electronic FitzHugh-Nagumo oscillator and an electrical line developed by resistively coupling 45 elementary cells. In the first section, the elementary cell characterization was undertaken in a deterministic regime. In the presence of a bichromatic stimulus, it is shown that when the low frequency component is subthreshold, its detection can be maximized for an optimal magnitude of the second component thanks to…
Trokšņa līmeņa novērtējums iekštelpās
2017
Bakalaura darba “Trokšņa līmeņa novērtējums iekštelpās” ietvaros veikti trokšņa līmeņa mērījumi daudzdzīvokļu māju dzīvojamās telpās dažādās Rīgas apkaimēs - Bolderājā, Vecrīgā un Maskavas forštatē. Novērtējums veikts izmantojot tiešo mērījumu metodi ar kalibrētu iekārtu PCE-322A. Iegūtie rezultāti apkopoti izvērtējot diennakts cikliskumu, mainību nedēļas laikā, ārējo faktoru ietekmi, kopā veiktas 8 mērījumu kampaņas. Iegūtie rezultāti liecina par normatīviem atbilstošu akustiskā trokšņa līmeni dzīvojāmo ēku telpās, kas nozīmē, ka tiek nodrošināta cilvēku aizsardzība pret akustiskā trokšņa nelabvēlīgo iedarbību.
Vitamin A deficiency increases noise susceptibility in guinea pigs.
1990
The effect of vitamin A deficiency in guinea pigs on noise-induced temporary threshold shift (TTS) was evaluated after short (15 min) acoustic overstimulation with a moderate (90 dB) broad-band white noise. Some guinea pigs were fed ad libitum a purified diet deficient in vitamin A (VAD group) until biochemical signs of deficiency occurred. A second, control group (VA group) received the same diet as well as 100 IU vitamin A daily by pharyngeal tube. Cochlear potentials were recorded by special computerized equipment using implanted electrodes. Before acoustic stimulation, a baseline value was determined with a test stimulus [90 dBA (A-filter according to usual DIN instructions)] correspond…
ATHENA X-IFU thermal filters development status toward the end of the instrument phase-A
2018
Copyright 2018 Society of Photo-Optical Instrumentation Engineers (SPIE). One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited. The X-ray Integral Field Unit (X-IFU) is one of the two instruments of the Athena astrophysics space mission approved by ESA in the Cosmic Vision 2015-2025 Science Programme. The X-IFU consists of a large array of transition edge sensor micro-calorimeters that will operate at 100 mK inside a sophisticated cryostat. A set of thin filters, highly transparent to X-rays, will be m…
Effect of internal noise on the relaxation time of an yttria stabilized zirconia-based memristor
2022
The effects of temperature on the switching kinetics of an yttrium-stabilized zirconia-based memristor from a low-resistance state to a high-resistance state have been experimentally investigated. It was found that the memristor relaxation time depends on the temperature in a non-monotonous way, with a maximum observed at the temperature close to 55 °C. This nonmonotonic behavior is a signature of the noise-enhanced stability phenomenon observed in all physical and complex systems characterized by metastable states.
Noise removal using a nonlinear two-dimensional diffusion network
1998
Un reseau electrique non lineaire bidimensionnel, constitue de N×N cellules identiques, et modelisant l’equation de Nagumo discrete est presente. A l’aide d’une nouvelle description de la fonction non lineaire, on peut predire analytiquement l’evolution temporelle de la partie coherente du signal, ainsi que celle des perturbations de petites amplitudes qui lui sont superposees. Enfin, des applications a l’amelioration du rapport signal sur bruit, ou au traitement d’images sont suggerees.
Noise estimation from digital step-model signal
2013
International audience; This paper addresses the noise estimation in the digital domain and proposes a noise estimator based on the step signal model. It is efficient for any distribution of noise because it does not rely only on the smallest amplitudes in the signal or image. The proposed approach uses polarized/directional derivatives and a nonlinear combination of these derivatives to estimate the noise distribution (e.g., Gaussian, Poisson, speckle, etc.). The moments of this measured distribution can be computed and are also calculated theoretically on the basis of noise distribution models. The 1D performances are detailed, and as our work is mostly dedicated to image processing, a 2D…