Analysis Of Noise Effects Research Articles

Comparative analysis of noise effects on wild and captive freshwater fish behaviour

Anthropogenic noise is globally increasing in aquatic ecosystems and causes adverse repercussions in many fish species, yet its effect on freshwater fish is not well understood. Here, we test the impact of boat noise on foraging and swimming behaviour on a number of wild freshwater fish species as well as captive black bullhead, Ameiurus melas, a common species in the Laurentian Great Lakes with known hearing specializations. In a laboratory setting, black bullhead were exposed to white noise, boat noise and a quiet control and monitored for changes in foraging behaviours and swimming patterns when presented with food. Black bullhead exposed to both boat noise and white noise foraged less and startled more in comparison to trials without noise. In a field setting, wild fishes with differing hearing capabilities were exposed to boat noise and a quiet control, then analysed for changes in both presence and foraging behaviour when presented with food. Field experiments were consistent with results from our laboratory study, resulting in decreased presence of wild fish and fewer foraging attempts made during boat noise exposure. However, the effects of noise in the field were highly variable by family, with fish in the Cyprinidae (or Leuciscidae) family, all of which have Weberian ossicle hearing specializations, exhibiting significantly larger decreases in feeding events and presence compared to other families (Gobiidae, Percidae and Centrarchidae) with more basic hearing abilities. Freshwater fishes alter their foraging behaviour during noise exposure, however, variation in hearing abilities may determine the extent to which their behaviour changes and the resulting degree of negative consequences.

Noise Analysis of Super-Regenerative Oscillators in Linear and Nonlinear Modes

A rigorous analysis of noise effects in super-regenerative oscillators (SROs), operating in both linear and nonlinear modes, is presented. For operation in the linear mode, two different analysis methods are presented. One is based on the calculation of linear-time variant (LTV) transfer function with respect to the input signal and the noise sources. The second method is based on a compact semianalytical formulation of the pulsed oscillator under the effect of the quench signal. The compact formulation also enables the analysis of the SRO in the nonlinear mode. It constitutes a fully new mathematical description of SROs, with general applicability, as it is not restricted to a particular oscillator topology. It relies on a numerical nonlinear black-box model of the stand-alone free-running oscillator, extracted from harmonic-balance simulations. This model is introduced into an envelope-domain formulation of the SRO at the fundamental frequency. Both the method based on LTV transfer functions and the semianalytical formulation take into account the cyclostationary nature of the SRO response to the noise sources. In the nonlinear mode, the variances of the amplitude and phase are calculated linearizing the formulation of the pulsed steady-state solution. The particular time variation of the phase variance is explained in detail and related to the onset and extinction of the oscillation in the presence of an RF input signal. The new analysis methods have been validated with both independent circuit-level simulations and measurements.

Necessity of Noise Map for Smart Protection from Environmental Noise

Since environmental noise, which has recently increased disputes and complaints, has a negative impact directly or indirectly on the lives of modern people, accurate analysis of noise effects and establishment of noise reduction method are essential. In the view of prevention, the noise map is very important for observing the overall noise distribution, identifying the noise sources, and preparing a noise reduction plan. In Korea, technical studies had conducted for producing the noise map. Various efforts also applied to prepare noise reduction measures, efficient introduction of regional noise maps, and establishment of management systems. However, there was a lack of experts and budgets to produce the noise map. The noise prediction formula and program were not standardized yet, consequently that it was difficult to build an infrastructure and update it. In this paper, by making a noise map for Chuncheon city using a smartphone application, we tried to produce a brief version of the noise maps which would increase people’s perception and interest toward. Furthermore, we introduced several good examples of the noise map from other countries. We expect that it is possible to reduce social costs and to improve the quality of people’s lives by academically approaching the multifaceted relationship between environmental noise, hearing, and health in Korea. Key Words: Noise map, Environmental noise, Noise exposure, Noise management, Geographic information system 중심 단어: 소음 지도, 환경 소음, 소음 ë ¸ì¶œ, 소음 관리, 지리 ì •ë³´ì‹œìŠ¤í œ

Noise effect analysis on edge detection in detecting digits with bilateral filter

Recognizing characters such as digits in natural images is a challenge in image processing. Edge detection is the first approach in image recognition. Edge detection using Bilateral Filter can improve image quality. However, in image processing, noise often occurs in the image which causes objects in the image to be more difficult to detect. In this paper, we conducted experiments to detect edges by using Bilateral filters on each edge detection operator against digits on SVHN which added noise and analyzes the effect of noise on edge detection. In the proposed method, edge detection of SVHN with Speckle noise does not produce many edges compared to Salt & Pepper noise so digits in SVHN can still be seen. The performance of the edge detection operator with Bilateral Filter can also be seen from the MSE and PSNR values. The lowest MSE value and the highest PSNR value is on Canny when detecting SVHN edges with Speckle noise.

Analysis of noise effects in a map-based neuron model with Canard-type quasiperiodic oscillations

A problem of the mathematical modeling and analysis of the complex mixed-mode stochastic oscillations in neural activity is studied. For the description of noise-induced transitions between regimes of neuron dynamics, 2D map-based system near Neimark–Sacker bifurcation is used as a conceptual model. We focus on the parametric zone of Canard explosion where the attractors (closed invariant curves) are extremely sensitive to noise. Using direct numerical simulation and semi-analytical approach based on the stochastic sensitivity analysis, we study the noise-induced transformations from unimodal oscillations to bimodal spiking oscillations. The supersensitive invariant curve which marks the epicenter of the Canard explosion is found. It is shown that for this curve, the noise-induced splitting occurs for extremely small random forcing. Changes of the amplitude and frequency properties of the stochastic mixed-mode oscillations are studied. The phenomenon of noise-induced transitions from order to chaos is discussed.

VLSI processor with a configurable processing element array for balanced feature extraction in high-resolution images

A VLSI processor employing a configurable processing element array (PEA) is developed for a newly proposed balanced feature extraction algorithm. In the algorithm, the input image is divided into square regions and the number of features is determined by noise effect analysis in each region. Regions of different sizes are used according to the resolutions and contents of input images. Therefore, inside the PEA, processing elements are hierarchically grouped for feature extraction in regions of different sizes. A proof-of-concept chip is fabricated using a 0.18 µm CMOS technology with a 32 × 32 PEA. From measurement results, a speed of 7.5 kfps is achieved for feature extraction in 128 × 128 pixel regions when operating the chip at 45 MHz, and a speed of 55 fps is also achieved for feature extraction in 1920 × 1080 pixel images.

Energy constrained frequency-domain normalized LMS algorithm for blind channel identification

This paper deals with the blind adaptive identification of single-input multi-output (SIMO) finite impulse response acoustic channels from noise-corrupted observations. The normalized multichannel frequency-domain least-mean-squares (NMCFLMS) algorithm [1] is known to be a very effective and efficient technique for identification of such channels when noise effects can be ignored. It, however, misconverges in presence of noise [2]. In this paper, we present an analysis of noise effects on the NMCFLMS algorithm and propose a novel technique for ameliorating such misconvergence characteristics of the NMCFLMS algorithm for blind channel identification (BCI) with noise by attaching a spectral constraint in the adaptation rule. Experimental results demonstrate that the robustness of the NMCFLMS algorithm for BCI can be significantly improved using such a constraint.

Modeling and Analysis of Noise Effects on Broadband Power-Line Communications

Power line noise is known to affect the performance of broadband power-line communications significantly. This paper presents a frequency-domain approach to characterize and model the statistical variation of power-line noise. The model considers both the background noise and the impulsive noise. The background noise model is based on statistical analysis of the results from two long-term measurements of noise spectrum conducted at two separate sites of a laboratory and a residential apartment. On the other hand, the impulsive noise model is obtained by direct measurements from the noise sources (i.e., various electrical household appliances). The amount of impulse noise reaching a power-line communications (PLC) receiver can then be determined with consideration of the channel transfer characteristics between the noise sources and the PLC receiver. Using these noise models, the performance of two major classes of digital modulation schemes, namely single-carrier modulation and multicarrier modulation, are analyzed and compared. It is found that the multicarrier scheme performs better than the single-carrier scheme when subjected to the observed power-line noise with non-Gaussian statistics.

Analysis of noise effects on DTI-based tractography using the brute-force and multi-ROI approach.

Diffusion tensor tractography based on line propagation is a promising and widely used technique, but it is known to be sensitive to noise and the size and location of the seed regions of interest (ROIs). The effects of these parameters on the tractography results were analyzed quantitatively using high-resolution diffusion tensor imaging (DTI) with a high signal-to-noise ratio (SNR) on a fixed mouse brain. The anterior commissure (AC), as judged from a T2-weighted image, was used as an anatomical reference within which the tracts could be located. Monte Carlo simulation was performed by adding Gaussian noise to the time domain data and repeating the tractography. Deviations of the tracking results were measured as a function of SNR. Such noise effects were evaluated for a simple one-ROI approach and a combined two-ROI and brute-force (BF) approach. The influence of ROI size and location for the two-ROI + BF approach was also analyzed. The results confirmed the hypothesis that one can increase the validity of DTI-based tractography by adopting the BF and multi-ROI approach, with respect to the simple one-ROI approach.

Analysis of Noise Effects on the Apodization and Chirped Grating Period of Fiber Bragg Gratings

Article Analysis of Noise Effects on the Apodization and Chirped Grating Period of Fiber Bragg Gratings was published on August 1, 2004 in the journal Journal of Optical Communications (volume 25, issue 4).

Analysis of noise effects on the nonlinear dynamics of synchronized oscillators

The higher sensitivity to noise of nonlinear systems near the onset of instability is analyzed here. The analysis is particularized to synchronized oscillators, studying the influence of the proximity to Hopf and Saddle-Node bifurcations. The calculations are compared with former scaling relationships and with results from time-domain integration. The average shift of bifurcation points due to noise perturbations is also analyzed. Two examples are shown: a cubic-nonlinearity oscillator and a 5 GHz hybrid oscillator, for experimental verifications.

Some principal issues in the analysis of noise effects on hearing in experimental animals

Some principal issues in the analysis of noise effects on hearing in experimental animals

Background Noise in Oscillators with R.F. Pushing†

ABSTRACT The analysis of noise effects in oscillators with one degree of freedom is extended to include non-linearities in which the frequency of oscillation is a function of amplitude of oscillation, i.e. an r.f. form of pushing. The pushing contributes f.m. noise with the spectral shape of the resonant circuit, in addition to the white f.m. noise present even without pushing. Also, pushing causes correlation between a.m. noise and f.m. noise, which introduces a small but observable asymmetry into the r.f. spectrum. Comparison to previously measured magnetron spectra shows only partial agreement; the discrepancy is attributed mainly to the multi-mode nature of the magnetron resonant circuit.