WorldWideScience

Sample records for random noise present

  1. Introduction to Random Signals and Noise

    NARCIS (Netherlands)

    van Etten, Wim

    Random signals and noise are present in many engineering systems and networks. Signal processing techniques allow engineers to distinguish between useful signals in audio, video or communication equipment, and interference, which disturbs the desired signal. With a strong mathematical grounding,

  2. Random signals and noise a mathematical introduction

    CERN Document Server

    Engelberg, Shlomo

    2011-01-01

    Understanding the nature of random signals and noise is critically important for detecting signals and for reducing and minimizing the effects of noise in applications such as communications and control systems. Outlining a variety of techniques and explaining when and how to use them, Random Signals and Noise: A Mathematical Introduction focuses on applications and practical problem solving rather than probability theory.A Firm FoundationBefore launching into the particulars of random signals and noise, the author outlines the elements of probability that are used throughout the book and incl

  3. Random noise de-noising and direct wave eliminating based on SVD method for ground penetrating radar signals

    Science.gov (United States)

    Liu, Cai; Song, Chao; Lu, Qi

    2017-09-01

    In this paper, we present a method using singular value decomposition (SVD) which aims at eliminating the random noise and direct wave from ground penetrating radar (GPR) signals. To demonstrate the validity and high efficiency of the SVD method in eliminating random noise, we compare the SVD de-noising method with wavelet threshold de-noising method and bandpass filtering method on both noisy synthetic data and field data. After that, we compare the SVD method with the mean trace deleting in eliminating direct wave on synthetic data and field data. We set general and quantitative criteria on choosing singular values to carry out the random noise de-noising and direct wave eliminating process. We find that by choosing appropriate singular values, SVD method can eliminate the random noise and direct wave in the GPR data validly and efficiently to improve the signal-to-noise ratio (SNR) of the GPR profiles and make effective reflection signals clearer.

  4. Effects of random noise in a dynamical model of love

    Energy Technology Data Exchange (ETDEWEB)

    Xu Yong, E-mail: hsux3@nwpu.edu.cn [Department of Applied Mathematics, Northwestern Polytechnical University, Xi' an 710072 (China); Gu Rencai; Zhang Huiqing [Department of Applied Mathematics, Northwestern Polytechnical University, Xi' an 710072 (China)

    2011-07-15

    Highlights: > We model the complexity and unpredictability of psychology as Gaussian white noise. > The stochastic system of love is considered including bifurcation and chaos. > We show that noise can both suppress and induce chaos in dynamical models of love. - Abstract: This paper aims to investigate the stochastic model of love and the effects of random noise. We first revisit the deterministic model of love and some basic properties are presented such as: symmetry, dissipation, fixed points (equilibrium), chaotic behaviors and chaotic attractors. Then we construct a stochastic love-triangle model with parametric random excitation due to the complexity and unpredictability of the psychological system, where the randomness is modeled as the standard Gaussian noise. Stochastic dynamics under different three cases of 'Romeo's romantic style', are examined and two kinds of bifurcations versus the noise intensity parameter are observed by the criteria of changes of top Lyapunov exponent and shape of stationary probability density function (PDF) respectively. The phase portraits and time history are carried out to verify the proposed results, and the good agreement can be found. And also the dual roles of the random noise, namely suppressing and inducing chaos are revealed.

  5. Modeling Random Telegraph Noise Under Switched Bias Conditions Using Cyclostationary RTS Noise

    NARCIS (Netherlands)

    van der Wel, A.P.; Klumperink, Eric A.M.; Vandamme, L.K.J.; Nauta, Bram

    In this paper, we present measurements and simulation of random telegraph signal (RTS) noise in n-channel MOSFETs under periodic large signal gate-source excitation (switched bias conditions). This is particularly relevant to analog CMOS circuit design where large signal swings occur and where LF

  6. Listening to the noise: random fluctuations reveal gene network parameters

    Energy Technology Data Exchange (ETDEWEB)

    Munsky, Brian [Los Alamos National Laboratory; Khammash, Mustafa [UCSB

    2009-01-01

    The cellular environment is abuzz with noise. The origin of this noise is attributed to the inherent random motion of reacting molecules that take part in gene expression and post expression interactions. In this noisy environment, clonal populations of cells exhibit cell-to-cell variability that frequently manifests as significant phenotypic differences within the cellular population. The stochastic fluctuations in cellular constituents induced by noise can be measured and their statistics quantified. We show that these random fluctuations carry within them valuable information about the underlying genetic network. Far from being a nuisance, the ever-present cellular noise acts as a rich source of excitation that, when processed through a gene network, carries its distinctive fingerprint that encodes a wealth of information about that network. We demonstrate that in some cases the analysis of these random fluctuations enables the full identification of network parameters, including those that may otherwise be difficult to measure. This establishes a potentially powerful approach for the identification of gene networks and offers a new window into the workings of these networks.

  7. Children's understanding of instructions presented in noise and reverberation.

    Science.gov (United States)

    Lewis, Dawna E; Manninen, Crystal M; Valente, Daniel L; Smith, Nicholas A

    2014-09-01

    This study examined children's ability to follow audio-visual instructions presented in noise and reverberation. Children (8-12 years of age) with normal hearing followed instructions in noise or noise plus reverberation. Performance was compared for a single talker (ST), multiple talkers speaking one at a time (MT), and multiple talkers with competing comments from other talkers (MTC). Working memory was assessed using measures of digit span. Performance was better for children in noise than for those in noise plus reverberation. In noise, performance for ST was better than for either MT or MTC, and performance for MT was better than for MTC. In noise plus reverberation, performance for ST and MT was better than for MTC, but there were no differences between ST and MT. Digit span did not account for significant variance in the task. Overall, children performed better in noise than in noise plus reverberation. However, differing patterns across conditions for the 2 environments suggested that the addition of reverberation may have affected performance in a way that was not apparent in noise alone. Continued research is needed to examine the differing effects of noise and reverberation on children's speech understanding.

  8. An analysis of noise reduction in variable reluctance motors using pulse position randomization

    Science.gov (United States)

    Smoot, Melissa C.

    1994-05-01

    The design and implementation of a control system to introduce randomization into the control of a variable reluctance motor (VRM) is presented. The goal is to reduce noise generated by radial vibrations of the stator. Motor phase commutation angles are dithered by 1 or 2 mechanical degrees to investigate the effect of randomization on acoustic noise. VRM commutation points are varied using a uniform probability density function and a 4 state Markov chain among other methods. The theory of VRM and inverter operation and a derivation of the major source of acoustic noise are developed. The experimental results show the effects of randomization. Uniform dithering and Markov chain dithering both tend to spread the noise spectrum, reducing peak noise components. No clear evidence is found to determine which is the optimum randomization scheme. The benefit of commutation angle randomization in reducing VRM loudness as perceived by humans is found to be questionable.

  9. Seismic random noise attenuation using shearlet and total generalized variation

    Science.gov (United States)

    Kong, Dehui; Peng, Zhenming

    2015-12-01

    Seismic denoising from a corrupted observation is an important part of seismic data processing which improves the signal-to-noise ratio (SNR) and resolution. In this paper, we present an effective denoising method to attenuate seismic random noise. The method takes advantage of shearlet and total generalized variation (TGV) regularization. Different regularity levels of TGV improve the quality of the final result by suppressing Gibbs artifacts caused by the shearlet. The problem is formulated as mixed constraints in a convex optimization. A Bregman algorithm is proposed to solve the proposed model. Extensive experiments based on one synthetic datum and two post-stack field data are done to compare performance. The results demonstrate that the proposed method provides superior effectiveness and preserve the structure better.

  10. Inversion-based data-driven time-space domain random noise attenuation method

    Science.gov (United States)

    Zhao, Yu-Min; Li, Guo-Fa; Wang, Wei; Zhou, Zhen-Xiao; Tang, Bo-Wen; Zhang, Wen-Bo

    2017-12-01

    Conventional time-space domain and frequency-space domain prediction filtering methods assume that seismic data consists of two parts, signal and random noise. That is, the so-called additive noise model. However, when estimating random noise, it is assumed that random noise can be predicted from the seismic data by convolving with a prediction error filter. That is, the source-noise model. Model inconsistencies, before and after denoising, compromise the noise attenuation and signal-preservation performances of prediction filtering methods. Therefore, this study presents an inversion-based time-space domain random noise attenuation method to overcome the model inconsistencies. In this method, a prediction error filter (PEF), is first estimated from seismic data; the filter characterizes the predictability of the seismic data and adaptively describes the seismic data's space structure. After calculating PEF, it can be applied as a regularized constraint in the inversion process for seismic signal from noisy data. Unlike conventional random noise attenuation methods, the proposed method solves a seismic data inversion problem using regularization constraint; this overcomes the model inconsistency of the prediction filtering method. The proposed method was tested on both synthetic and real seismic data, and results from the prediction filtering method and the proposed method are compared. The testing demonstrated that the proposed method suppresses noise effectively and provides better signal-preservation performance.

  11. Seismic random noise attenuation using modified wavelet thresholding

    Directory of Open Access Journals (Sweden)

    Qi-sheng Zhang

    2017-01-01

    Full Text Available In seismic exploration, random noise deteriorates the quality of acquired data. This study analyzed existing denoising methods used in seismic exploration from the perspective of random noise. Wavelet thresholding offers a new approach to reducing random noise in simulation results, synthetic data, and real data. A modified wavelet threshold function was developed by considering the merits and demerits of conventional soft and hard thresholding schemes. A MATLAB (matrix laboratory simulation model was used to compare the signal-to-noise ratios (SNRs and mean square errors (MSEs of the soft, hard, and modified threshold functions. The results demonstrated that the modified threshold function can avoid the pseudo-Gibbs phenomenon and produce a higher SNR than the soft and hard threshold functions. A seismic convolution model was built using seismic wavelets to verify the effectiveness of different denoising methods. The model was used to demonstrate that the modified thresholding scheme can effectively reduce random noise in seismic data and retain the desired signal. The application of the proposed tool to a real raw seismogram recorded during a land seismic exploration experiment located in north China clearly demonstrated its efficiency for random noise attenuation.

  12. Mathematical Analysis of Random Noise - and Appendixes

    Science.gov (United States)

    1952-01-01

    ONLY; ADMINISTRATIVE/OPERATIONAL USE; 24 FEB 1999. OTHER REQUESTS SHALL BE REFERRED THROUGH DEFENSE TECHNICAL INFORMATION CENTER, DTIC-BCS, 8725 JOHN J...and (2.1-6) give fw(g) dg = .- , () slic 7r go (2.2-4) 00r) = j cos 2rfr d[j w(g) dg] 1’ This is done by Wiener,ŕ loc. cit., and by G. W. Kenrick ...pp. 176-196 (Jan. 1929). Kenrick appears to be one of the first to apply, to noise problems, the correlatir’ functi.rn mlthnd of camputing the power

  13. Overview of presentations : wind turbine noise 2009, Aalborg, Denmark

    Energy Technology Data Exchange (ETDEWEB)

    Howe, B. [HGC Engineering, Mississauga, ON (Canada)

    2009-07-01

    In 2009, a wind turbine noise conference was held in Aalborg, Germany. It was the third biannual conference and was sponsored by the Institute of Noise Control Engineering in Europe. There were 50 papers, 160 delegates, in 25 countries. This paper presented a summary of some of the presentations highlighting the Canadian Wind Energy Association's best practice guide; Ontario Ministry of the Environment's guidelines, and HGC Engineering's experience with auditing wind farms. Sound level criteria and sound level impact assessment for wind turbine sound were first discussed. The impact of wind shear and the characteristics of wind turbine sound were also summarized. Other topics that were addressed included wind turbine sound and health; annoyance from wind turbine sound; modelling and measurement limitations for wind turbine sound; and audit experience. It was concluded that in order to improve noise assessment, efforts should include monitoring at several locations over longer periods, correlating sound levels to wind speed, and statistically assessing percentile noise levels, and frequency analysis. tabs., figs.

  14. Random noise attenuation using an improved anisotropic total variation regularization

    Science.gov (United States)

    Gemechu, Diriba; Yuan, Huan; Ma, Jianwei

    2017-09-01

    In seismic data processing, attenuation of random noise from the observed data is the basic step which improves the signal-to-noise ratio (SNR) of seismic data. In this paper, we proposed an anisotropic total bounded variation regularization approach to attenuate noise. An improved constraint convex optimization model is formulated for this approach and then the split Bregman algorithm is used to solve the optimization model. Generalized cross validation (GCV) technique is used to estimate the regularization parameter. Synthetic and real seismic data are considered to show the out performance of the proposed method in terms of event-preserving denoising, in comparison with FX deconvolution, shearlet hard thresholding, and anisotropic total variation methods. The numerical results indicate that the proposed method effectively attenuates random noise by preserving the structure and important features of seismic data.

  15. Diffusion MRI noise mapping using random matrix theory

    Science.gov (United States)

    Veraart, Jelle; Fieremans, Els; Novikov, Dmitry S.

    2016-01-01

    Purpose To estimate the spatially varying noise map using a redundant magnitude MR series. Methods We exploit redundancy in non-Gaussian multi-directional diffusion MRI data by identifying its noise-only principal components, based on the theory of noisy covariance matrices. The bulk of PCA eigenvalues, arising due to noise, is described by the universal Marchenko-Pastur distribution, parameterized by the noise level. This allows us to estimate noise level in a local neighborhood based on the singular value decomposition of a matrix combining neighborhood voxels and diffusion directions. Results We present a model-independent local noise mapping method capable of estimating noise level down to about 1% error. In contrast to current state-of-the art techniques, the resultant noise maps do not show artifactual anatomical features that often reflect physiological noise, the presence of sharp edges, or a lack of adequate a priori knowledge of the expected form of MR signal. Conclusions Simulations and experiments show that typical diffusion MRI data exhibit sufficient redundancy that enables accurate, precise, and robust estimation of the local noise level by interpreting the PCA eigenspectrum in terms of the Marchenko-Pastur distribution. PMID:26599599

  16. Random Noise Monopulse Radar System for Covert Tracking of Targets

    Science.gov (United States)

    Narayanan, Ram M.

    2002-07-01

    The University of Nebraska is currently developing a unique monopulse radar concept based on the use of random noise signal for covert tracking applications. This project is funded by the Missile Defense Agency (MDA). The advantage of this system over conventional frequency-modulated continuous wave (FMCW) or short pulse systems is its covertness resulting from the random waveform's immunity from interception and jamming. The system integrates a novel heterodyne correlation receiver with conventional monopulse architecture. Based on the previous work such as random noise interferometry, a series of theoretical analysis and simulations were conducted to examine the potential performance of this monopulse system. Furthermore, a prototype system is under development to exploit practical design aspects of phase comparison angle measurement. It is revealed that random noise monopulse radar can provide the same function as traditional monopulse radar, i.e., implement range and angular estimation and tracking in real time. The bandwidth of random noise signal can be optimized to achieve the best range resolution as well as the angular accuracy.

  17. Random noise characterization on the carrying capacities of a ...

    African Journals Online (AJOL)

    We have utilised the technique of a numerical simulation to study the impact of environmental random noise on the carrying capacities of a mathematical model of ... some sort of a sustainable mitigation strategy that is capable of providing a long term solution to the impact of crude oil pollution on the Ogoni ecosystem.

  18. Open quantum random walk in terms of quantum Bernoulli noise

    Science.gov (United States)

    Wang, Caishi; Wang, Ce; Ren, Suling; Tang, Yuling

    2018-03-01

    In this paper, we introduce an open quantum random walk, which we call the QBN-based open walk, by means of quantum Bernoulli noise, and study its properties from a random walk point of view. We prove that, with the localized ground state as its initial state, the QBN-based open walk has the same limit probability distribution as the classical random walk. We also show that the probability distributions of the QBN-based open walk include those of the unitary quantum walk recently introduced by Wang and Ye (Quantum Inf Process 15:1897-1908, 2016) as a special case.

  19. A Stochastic Simulation Framework for the Prediction of Strategic Noise Mapping and Occupational Noise Exposure Using the Random Walk Approach

    Science.gov (United States)

    Haron, Zaiton; Bakar, Suhaimi Abu; Dimon, Mohamad Ngasri

    2015-01-01

    Strategic noise mapping provides important information for noise impact assessment and noise abatement. However, producing reliable strategic noise mapping in a dynamic, complex working environment is difficult. This study proposes the implementation of the random walk approach as a new stochastic technique to simulate noise mapping and to predict the noise exposure level in a workplace. A stochastic simulation framework and software, namely RW-eNMS, were developed to facilitate the random walk approach in noise mapping prediction. This framework considers the randomness and complexity of machinery operation and noise emission levels. Also, it assesses the impact of noise on the workers and the surrounding environment. For data validation, three case studies were conducted to check the accuracy of the prediction data and to determine the efficiency and effectiveness of this approach. The results showed high accuracy of prediction results together with a majority of absolute differences of less than 2 dBA; also, the predicted noise doses were mostly in the range of measurement. Therefore, the random walk approach was effective in dealing with environmental noises. It could predict strategic noise mapping to facilitate noise monitoring and noise control in the workplaces. PMID:25875019

  20. Calibration of Correlation Radiometers Using Pseudo-Random Noise Signals

    Directory of Open Access Journals (Sweden)

    Sebastián Pantoja

    2009-08-01

    Full Text Available The calibration of correlation radiometers, and particularly aperture synthesis interferometric radiometers, is a critical issue to ensure their performance. Current calibration techniques are based on the measurement of the cross-correlation of receivers’ outputs when injecting noise from a common noise source requiring a very stable distribution network. For large interferometric radiometers this centralized noise injection approach is very complex from the point of view of mass, volume and phase/amplitude equalization. Distributed noise injection techniques have been proposed as a feasible alternative, but are unable to correct for the so-called “baseline errors” associated with the particular pair of receivers forming the baseline. In this work it is proposed the use of centralized Pseudo-Random Noise (PRN signals to calibrate correlation radiometers. PRNs are sequences of symbols with a long repetition period that have a flat spectrum over a bandwidth which is determined by the symbol rate. Since their spectrum resembles that of thermal noise, they can be used to calibrate correlation radiometers. At the same time, since these sequences are deterministic, new calibration schemes can be envisaged, such as the correlation of each receiver’s output with a baseband local replica of the PRN sequence, as well as new distribution schemes of calibration signals. This work analyzes the general requirements and performance of using PRN sequences for the calibration of microwave correlation radiometers, and particularizes the study to a potential implementation in a large aperture synthesis radiometer using an optical distribution network.

  1. Calibration of correlation radiometers using pseudo-random noise signals.

    Science.gov (United States)

    Pérez, Isaac Ramos; Bosch-Lluis, Xavi; Camps, Adriano; Alvarez, Nereida Rodriguez; Hernandez, Juan Fernando Marchán; Domènech, Enric Valencia; Vernich, Carlos; de la Rosa, Sonia; Pantoja, Sebastián

    2009-01-01

    The calibration of correlation radiometers, and particularly aperture synthesis interferometric radiometers, is a critical issue to ensure their performance. Current calibration techniques are based on the measurement of the cross-correlation of receivers' outputs when injecting noise from a common noise source requiring a very stable distribution network. For large interferometric radiometers this centralized noise injection approach is very complex from the point of view of mass, volume and phase/amplitude equalization. Distributed noise injection techniques have been proposed as a feasible alternative, but are unable to correct for the so-called "baseline errors" associated with the particular pair of receivers forming the baseline. In this work it is proposed the use of centralized Pseudo-Random Noise (PRN) signals to calibrate correlation radiometers. PRNs are sequences of symbols with a long repetition period that have a flat spectrum over a bandwidth which is determined by the symbol rate. Since their spectrum resembles that of thermal noise, they can be used to calibrate correlation radiometers. At the same time, since these sequences are deterministic, new calibration schemes can be envisaged, such as the correlation of each receiver's output with a baseband local replica of the PRN sequence, as well as new distribution schemes of calibration signals. This work analyzes the general requirements and performance of using PRN sequences for the calibration of microwave correlation radiometers, and particularizes the study to a potential implementation in a large aperture synthesis radiometer using an optical distribution network.

  2. Multichannel active control of random noise in a small reverberant room

    DEFF Research Database (Denmark)

    Laugesen, Søren; Elliott, Stephen J.

    1993-01-01

    An algorithm for multichannel adaptive IIR (infinite impulse response) filtering is presented and applied to the active control of broadband random noise in a small reverberant room. Assuming complete knowledge of the primary noise, the theoretically optimal reductions of acoustic energy...... with the primary noise field generated by a panel excited by a loudspeaker in an adjoining room. These results show that far better performances are provided by IIR and FIR filters when the primary source has a lightly damped dynamic behavior which the active controller must model...... multichannel FIR (finite impulse response) and IIR filters are then compared for a four-secondary-source, eight-error microphone active control system, and it is found that for the present application FIR filters are sufficient when the primary noise source is a loudspeaker. Some experiments are then presented...

  3. Application of variational mode decomposition to seismic random noise reduction

    Science.gov (United States)

    Liu, Wei; Cao, Siyuan; Wang, Zhiming

    2017-08-01

    We have proposed a new denoising method for the simultaneous noise reduction and preservation of seismic signals based on variational mode decomposition (VMD). VMD is a recently developed adaptive signal decomposition method and an advance in non-stationary signal analysis. It solves the mode-mixing and non-optimal reconstruction performance problems of empirical mode decomposition that have existed for a long time. By using VMD, a multi-component signal can be non-recursively decomposed into a series of quasi-orthogonal intrinsic mode functions (IMFs), each of which has a relatively local frequency range. Meanwhile, the signal will focus on a smaller number of obtained IMFs after decomposition, and thus the denoised result is able to be obtained by reconstructing these signal-dominant IMFs. Synthetic examples are given to demonstrate the effectiveness of the proposed approach and comparison is made with the complete ensemble empirical mode decomposition, which demonstrates that the VMD algorithm has lower computational cost and better random noise elimination performance. The application of on field seismic data further illustrates the superior performance of our method in both random noise attenuation and the recovery of seismic events.

  4. DS/LPI autocorrelation detection in noise plus random-tone interference

    Science.gov (United States)

    Hinedi, Sami; Polydoros, Andreas

    1990-01-01

    An analysis is presented of a frequency-noncoherent, two-lag autocorrelation statistic for the wideband detection of random binary phase-shift keying (BPSK) signals in noise plus random multitone interference. It is shown that this detector is quite robust to the presence or absence of interference and its specific parameter values contrary to an energy detector. The rule assumes knowledge of the data rate and the active scenario under H0. The purpose of the paper is to promote the real-time autocorrelation domain and its samples (lags) as a viable approach for detecting random signals in dense environments.

  5. Signal preserving and seismic random noise attenuation by Hurst exponent based time-frequency peak filtering

    Science.gov (United States)

    Zhang, Chao; Li, Yue; Lin, Hongbo; Yang, Baojun

    2015-11-01

    Attenuating random noise is of great significance in seismic data processing. In recent years, time-frequency peak filtering (TFPF) has been successfully applied to seismic random noise attenuation field. However, a fixed window length (WL) is used in the conventional TFPF. Since a short WL in the TFPF is used to preserve signals while a long WL can eliminate random noise effectively, signal preserving and noise attenuation cannot be balanced by a fixed WL especially when the signal-to-noise ratio of the noisy seismic record is low. Thus, we need to divide a noisy signal into signal and noise segments before the filtering. Then a short WL is used to the signal segments to preserve signals and a long WL is chosen for noise segments to eliminate random noise. In this paper, we test the smoothness of signals and random noise in time using the Hurst exponent which is a statistic for representing smoothness characteristics of signals. The time-series of signals with higher smoothness which lead to larger Hurst exponent values, however random noise is a random series in time without fixed waveforms and thus its smoothness is low, so the signal and noise segments can be divided by the Hurst exponent values. After the segmentation, we can adopt different filtering WLs in the TFPF for different segments to make a trade-off between signal preserving and random noise attenuation. Synthetic and real data experiments demonstrate that the proposed method can remove random noise from seismic record and preserve reflection events effectively.

  6. MEMS microphone innovations towards high signal to noise ratios (Conference Presentation) (Plenary Presentation)

    Science.gov (United States)

    Dehé, Alfons

    2017-06-01

    After decades of research and more than ten years of successful production in very high volumes Silicon MEMS microphones are mature and unbeatable in form factor and robustness. Audio applications such as video, noise cancellation and speech recognition are key differentiators in smart phones. Microphones with low self-noise enable those functions. Backplate-free microphones enter the signal to noise ratios above 70dB(A). This talk will describe state of the art MEMS technology of Infineon Technologies. An outlook on future technologies such as the comb sensor microphone will be given.

  7. Error Bounds Due to Random Noise in Cylindrical Near-Field Measurements

    OpenAIRE

    Romeu Robert, Jordi; Jofre Roca, Lluís

    1991-01-01

    The far field errors due to near field random noise are statistically bounded when performing cylindrical near to far field transform. In this communication, the far field noise variance it is expressed as a function of the measurement parameters and the near field noise variance. Peer Reviewed

  8. Random wavelet transforms, algebraic geometric coding, and their applications in signal compression and de-noising

    Energy Technology Data Exchange (ETDEWEB)

    Bieleck, T.; Song, L.M.; Yau, S.S.T. [Univ. of Illinois, Chicago, IL (United States); Kwong, M.K. [Argonne National Lab., IL (United States). Mathematics and Computer Science Div.

    1995-07-01

    The concepts of random wavelet transforms and discrete random wavelet transforms are introduced. It is shown that these transforms can lead to simultaneous compression and de-noising of signals that have been corrupted with fractional noises. Potential applications of algebraic geometric coding theory to encode the ensuing data are also discussed.

  9. Active random noise control using adaptive learning rate neural networks with an immune feedback law

    Science.gov (United States)

    Sasaki, Minoru; Kuribayashi, Takumi; Ito, Satoshi

    2005-12-01

    In this paper an active random noise control using adaptive learning rate neural networks with an immune feedback law is presented. The adaptive learning rate strategy increases the learning rate by a small constant if the current partial derivative of the objective function with respect to the weight and the exponential average of the previous derivatives have the same sign, otherwise the learning rate is decreased by a proportion of its value. The use of an adaptive learning rate attempts to keep the learning step size as large as possible without leading to oscillation. In the proposed method, because of the immune feedback law change a learning rate of the neural networks individually and adaptively, it is expected that a cost function minimize rapidly and training time is decreased. Numerical simulations and experiments of active random noise control with the transfer function of the error path will be performed, to validate the convergence properties of the adaptive learning rate Neural Networks with the immune feedback law. Control results show that adaptive learning rate Neural Networks control structure can outperform linear controllers and conventional neural network controller for the active random noise control.

  10. Detection of random signals in dependent Gaussian noise

    CERN Document Server

    Gualtierotti, Antonio F

    2015-01-01

    The book presents the necessary mathematical basis to obtain and rigorously use likelihoods for detection problems with Gaussian noise. To facilitate comprehension the text is divided into three broad areas –  reproducing kernel Hilbert spaces, Cramér-Hida representations and stochastic calculus – for which a somewhat different approach was used than in their usual stand-alone context. One main applicable result of the book involves arriving at a general solution to the canonical detection problem for active sonar in a reverberation-limited environment. Nonetheless, the general problems dealt with in the text also provide a useful framework for discussing other current research areas, such as wavelet decompositions, neural networks, and higher order spectral analysis. The structure of the book, with the exposition presenting as many details as necessary, was chosen to serve both those readers who are chiefly interested in the results and those who want to learn the material from scratch. Hence, the text...

  11. Frequency-space prediction filtering for acoustic clutter and random noise attenuation in ultrasound imaging

    Science.gov (United States)

    Shin, Junseob; Huang, Lianjie

    2016-04-01

    Frequency-space prediction filtering (FXPF), also known as FX deconvolution, is a technique originally developed for random noise attenuation in seismic imaging. FXPF attempts to reduce random noise in seismic data by modeling only real signals that appear as linear or quasilinear events in the aperture domain. In medical ultrasound imaging, channel radio frequency (RF) signals from the main lobe appear as horizontal events after receive delays are applied while acoustic clutter signals from off-axis scatterers and electronic noise do not. Therefore, FXPF is suitable for preserving only the main-lobe signals and attenuating the unwanted contributions from clutter and random noise in medical ultrasound imaging. We adapt FXPF to ultrasound imaging, and evaluate its performance using simulated data sets from a point target and an anechoic cyst. Our simulation results show that using only 5 iterations of FXPF achieves contrast-to-noise ratio (CNR) improvements of 67 % in a simulated noise-free anechoic cyst and 228 % in a simulated anechoic cyst contaminated with random noise of 15 dB signal-to-noise ratio (SNR). Our findings suggest that ultrasound imaging with FXPF attenuates contributions from both acoustic clutter and random noise and therefore, FXPF has great potential to improve ultrasound image contrast for better visualization of important anatomical structures and detection of diseased conditions.

  12. Dyslexic adults can learn from repeated stimulus presentation but have difficulties in excluding external noise.

    Directory of Open Access Journals (Sweden)

    Rachel L Beattie

    Full Text Available We examined whether the characteristic impairments of dyslexia are due to a deficit in excluding external noise or a deficit in taking advantage of repeated stimulus presentation. We compared non-impaired adults and adults with poor reading performance on a visual letter detection task that varied two aspects: the presence or absence of background visual noise, and a small or large stimulus set. There was no interaction between group and stimulus set size, indicating that the poor readers took advantage of repeated stimulus presentation as well as the non-impaired readers. The poor readers had higher thresholds than non-impaired readers in the presence of high external noise, but not in the absence of external noise. The results support the hypothesis that an external noise exclusion deficit, not a perceptual anchoring deficit, impairs reading for adults.

  13. Diffusion MRI noise mapping using random matrix theory

    National Research Council Canada - National Science Library

    Veraart, Jelle; Fieremans, Els; Novikov, Dmitry S

    2016-01-01

    .... Methods We exploit redundancy in non-Gaussian distributed multidirectional diffusion MRI data by identifying its noise-only principal components, based on the theory of noisy covariance matrices...

  14. Fluorescence microscopy image noise reduction using a stochastically-connected random field model.

    Science.gov (United States)

    Haider, S A; Cameron, A; Siva, P; Lui, D; Shafiee, M J; Boroomand, A; Haider, N; Wong, A

    2016-02-17

    Fluorescence microscopy is an essential part of a biologist's toolkit, allowing assaying of many parameters like subcellular localization of proteins, changes in cytoskeletal dynamics, protein-protein interactions, and the concentration of specific cellular ions. A fundamental challenge with using fluorescence microscopy is the presence of noise. This study introduces a novel approach to reducing noise in fluorescence microscopy images. The noise reduction problem is posed as a Maximum A Posteriori estimation problem, and solved using a novel random field model called stochastically-connected random field (SRF), which combines random graph and field theory. Experimental results using synthetic and real fluorescence microscopy data show the proposed approach achieving strong noise reduction performance when compared to several other noise reduction algorithms, using quantitative metrics. The proposed SRF approach was able to achieve strong performance in terms of signal-to-noise ratio in the synthetic results, high signal to noise ratio and contrast to noise ratio in the real fluorescence microscopy data results, and was able to maintain cell structure and subtle details while reducing background and intra-cellular noise.

  15. Large Signal Excitation Measurement Techniques for Random Telegraph Signal Noise in MOSFETs

    NARCIS (Netherlands)

    Hoekstra, E.

    2005-01-01

    This paper introduces large signal excitation measurement techniques to analyze random telegraph signal (RTS) noise originating from oxide-traps in MOSFETs. The paper concentrates on the trap-occupancy, which relates directly to the generated noise. The proposed measurement technique makes

  16. Large Signal Excitation Measurement Techniques for Random Telegraph Signal Noise in MOSFETs

    NARCIS (Netherlands)

    Hoekstra, E.; Kolhatkar, J.S.; van der Wel, A.P.; Salm, Cora; Klumperink, Eric A.M.

    2005-01-01

    This paper introduces large signal excitation measurement techniques to analyze Random Telegraph Signal (RTS) noise originating from oxide-traps in MOSFETs. The paper concentrates on the trap-occupancy, which relates directly to the generated noise. The proposed measurement technique makes

  17. Random-Resistor-Random-Temperature Kirchhoff-Law-Johnson-Noise (RRRT-KLJN Key Exchange

    Directory of Open Access Journals (Sweden)

    Kish Laszlo B.

    2016-03-01

    Full Text Available We introduce two new Kirchhoff-law-Johnson-noise (KLJN secure key distribution schemes which are generalizations of the original KLJN scheme. The first of these, the Random-Resistor (RR- KLJN scheme, uses random resistors with values chosen from a quasi-continuum set. It is well-known since the creation of the KLJN concept that such a system could work in cryptography, because Alice and Bob can calculate the unknown resistance value from measurements, but the RR-KLJN system has not been addressed in prior publications since it was considered impractical. The reason for discussing it now is the second scheme, the Random Resistor Random Temperature (RRRT- KLJN key exchange, inspired by a recent paper of Vadai, Mingesz and Gingl, wherein security was shown to be maintained at non-zero power flow. In the RRRT-KLJN secure key exchange scheme, both the resistances and their temperatures are continuum random variables. We prove that the security of the RRRT-KLJN scheme can prevail at a non-zero power flow, and thus the physical law guaranteeing security is not the Second Law of Thermodynamics but the Fluctuation-Dissipation Theorem. Alice and Bob know their own resistances and temperatures and can calculate the resistance and temperature values at the other end of the communication channel from measured voltage, current and power-flow data in the wire. However, Eve cannot determine these values because, for her, there are four unknown quantities while she can set up only three equations. The RRRT-KLJN scheme has several advantages and makes all former attacks on the KLJN scheme invalid or incomplete.

  18. Analogies between colored Lévy noise and random channel approach to disordered kinetics

    Science.gov (United States)

    Vlad, Marcel O.; Velarde, Manuel G.; Ross, John

    2004-02-01

    We point out some interesting analogies between colored Lévy noise and the random channel approach to disordered kinetics. These analogies are due to the fact that the probability density of the Lévy noise source plays a similar role as the probability density of rate coefficients in disordered kinetics. Although the equations for the two approaches are not identical, the analogies can be used for deriving new, useful results for both problems. The random channel approach makes it possible to generalize the fractional Uhlenbeck-Ornstein processes (FUO) for space- and time-dependent colored noise. We describe the properties of colored noise in terms of characteristic functionals, which are evaluated by using a generalization of Huber's approach to complex relaxation [Phys. Rev. B 31, 6070 (1985)]. We start out by investigating the properties of symmetrical white noise and then define the Lévy colored noise in terms of a Langevin equation with a Lévy white noise source. We derive exact analytical expressions for the various characteristic functionals, which characterize the noise, and a functional fractional Fokker-Planck equation for the probability density functional of the noise at a given moment in time. Second, by making an analogy between the theory of colored noise and the random channel approach to disordered kinetics, we derive fractional equations for the evolution of the probability densities of the random rate coefficients in disordered kinetics. These equations serve as a basis for developing methods for the evaluation of the statistical properties of the random rate coefficients from experimental data. Special attention is paid to the analysis of systems for which the observed kinetic curves can be described by linear or nonlinear stretched exponential kinetics.

  19. Statistical analysis of random telegraph noise in HfO2-based RRAM devices in LRS

    Science.gov (United States)

    Puglisi, Francesco Maria; Pavan, Paolo; Larcher, Luca; Padovani, Andrea

    2015-11-01

    In this work, we present a thorough statistical characterization of Random Telegraph Noise (RTN) in HfO2-based Resistive Random Access Memory (RRAM) cells in Low Resistive State (LRS). Devices are tested under a variety of operational conditions. A Factorial Hidden Markov Model (FHMM) analysis is exploited to extrapolate the properties of the traps causing multi-level RTN in LRS. The trapping and de-trapping of charge carriers into/out of defects located in the proximity of the conductive filament results in a shielding effect on a portion of the conductive filament, leading to the observed RTN current fluctuations. It is found that both oxygen vacancies and oxygen ions defects may be responsible for the observed RTN. The variations of the current observed at subsequent set/reset cycles are instead attributed to the stochastic variations in the filament due to oxidation/reduction processes during reset and set operations, respectively.

  20. DS/LPI autocorrelation detection in noise plus random-tone interference. [Direct Sequence Low-Probabilty of Intercept

    Science.gov (United States)

    Hinedi, S.; Polydoros, A.

    1988-01-01

    The authors present and analyze a frequency-noncoherent two-lag autocorrelation statistic for the wideband detection of random BPSK signals in noise-plus-random-multitone interference. It is shown that this detector is quite robust to the presence or absence of interference and its specific parameter values, contrary to the case of an energy detector. The rule assumes knowledge of the data rate and the active scenario under H0. It is concluded that the real-time autocorrelation domain and its samples (lags) are a viable approach for detecting random signals in dense environments.

  1. Reduction of randomness in seismic noise as a short-term precursor to a volcanic eruption.

    Science.gov (United States)

    Glynn, C C; Konstantinou, K I

    2016-11-24

    Ambient seismic noise is characterized by randomness incurred by the random position and strength of the noise sources as well as the heterogeneous properties of the medium through which it propagates. Here we use ambient noise data recorded prior to the 1996 Gjálp eruption in Iceland in order to show that a reduction of noise randomness can be a clear short-term precursor to volcanic activity. The eruption was preceded on 29 September 1996 by a Mw ~5.6 earthquake that occurred in the caldera rim of the Bárdarbunga volcano. A significant reduction of randomness started occurring 8 days before the earthquake and 10 days before the onset of the eruption. This reduction was observed even at stations more than 100 km away from the eruption site. Randomness increased to its previous levels 160 minutes after the Bárdarbunga earthquake, during which time aftershocks migrated from the Bárdarbunga caldera to a site near the Gjálp eruption fissure. We attribute this precursory reduction of randomness to the lack of higher frequencies (>1 Hz) in the noise wavefield caused by high absorption losses as hot magma ascended in the upper crust.

  2. Random telegraphic voltage noise due to thermal bi-stability in a superconducting weak link

    Science.gov (United States)

    Biswas, Sourav; Kumar, Nikhil; Winkelmann, C. B.; Courtois, Herve; Gupta, Anjan K.

    2016-05-01

    We investigated the random telegraphic voltage noise signal in the hysteretic bi-stable state of a superconducting weak link device. Fluctuation induced random switching between zero voltage state and non-zero-voltage state gives rise to a random telegraphic voltage signal in time domain. This telegraphic noise is used to find the mean lifetime of each of the two states. The mean life time in the zero voltage state is found to decrease with increasing bias current while that of resistive state increases and thus the two cross at certain bias current. We qualitatively discuss this observed switching behavior as arising from the bi-stable nature.

  3. Information Encoding on a Pseudo Random Noise Radar Waveform

    Science.gov (United States)

    2013-03-01

    antenna under test AWG arbitrary waveform generator AWGN additive white Gaussian noise BPSK binary phase shift keying CDMA code division multiple...focused on the orthogonal frequency-division multiplexing (OFDM) and code division multiple access ( CDMA ) waveforms. The Ohio State University has...components into a single unit allows for a more mobile compact platform. The plan is diagrammed in Figure 3.5. Figure 3.5: Planned modifications to

  4. Speech Perception in Noise Deficits in Japanese Children with Reading Difficulties: Effects of Presentation Rate

    Science.gov (United States)

    Inoue, Tomohiro; Higashibara, Fumiko; Okazaki, Shinji; Maekawa, Hisao

    2011-01-01

    We examined the effects of presentation rate on speech perception in noise and its relation to reading in 117 typically developing (TD) children and 10 children with reading difficulties (RD) in Japan. Responses in a speech perception task were measured for speed, accuracy, and stability in two conditions that varied stimulus presentation rate:…

  5. Noise

    Science.gov (United States)

    Noise is all around you, from televisions and radios to lawn mowers and washing machines. Normally, you ... sensitive structures of the inner ear and cause noise-induced hearing loss. More than 30 million Americans ...

  6. Effect of hearing aid release time and presentation level on speech perception in noise in elderly individuals with hearing loss.

    Science.gov (United States)

    Pottackal Mathai, Jijo; Mohammed, Hasheem

    2017-02-01

    To investigate the effect of compression time settings and presentation levels on speech perception in noise for elderly individuals with hearing loss. To compare aided speech perception performance in these individuals with age-matched normal hearing subjects. Twenty (normal hearing) participants within the age range of 60-68 years and 20 (mild-to-moderate sensorineural hearing loss) in the age range of 60-70 years were randomly recruited for the study. In the former group, SNR-50 was determined using phonetically balanced sentences that were mixed with speech-shaped noise presented at the most comfortable level. In the SNHL group, aided SNR-50 was determined at three different presentation levels (40, 60, and 80 dB HL) after fitting binaural hearing aids that had different compression time settings (fast and slow). In the SNHL group, slow compression time settings showed significantly better SNR-50 compared to fast release time. In addition, the mean of SNR-50 in the SNHL group was comparable to normal hearing participants while using a slow release time. A hearing aid with slow compression time settings led to significantly better speech perception in noise, compared to that of a hearing aid that had fast compression time settings.

  7. The Miniaturization of the AFIT Random Noise Radar

    Science.gov (United States)

    2013-03-01

    Gaussian , RI = σ2n. If k is chosen to be 1/σ2, the result is simply [30] H = X∗. (2.35) In other words, the ideal filter in the presence of white noise...Virtex-5. The HDL code for the correlation algorithm consists of a combination of Verilog , schematic- based coding , and Xilinx IP Cores. Verilog is an HDL...synthesizable. In addition to Verilog coding , the Xilinx ISE includes a graphical method for representing the register-transfer level circuits needed for

  8. Auto Regressive Moving Average (ARMA) Modeling Method for Gyro Random Noise Using a Robust Kalman Filter.

    Science.gov (United States)

    Huang, Lei

    2015-09-30

    To solve the problem in which the conventional ARMA modeling methods for gyro random noise require a large number of samples and converge slowly, an ARMA modeling method using a robust Kalman filtering is developed. The ARMA model parameters are employed as state arguments. Unknown time-varying estimators of observation noise are used to achieve the estimated mean and variance of the observation noise. Using the robust Kalman filtering, the ARMA model parameters are estimated accurately. The developed ARMA modeling method has the advantages of a rapid convergence and high accuracy. Thus, the required sample size is reduced. It can be applied to modeling applications for gyro random noise in which a fast and accurate ARMA modeling method is required.

  9. Emergence of deterministic Green's functions from noise generated by finite random sources.

    Science.gov (United States)

    Godin, Oleg A

    2009-12-01

    Two-point correlation functions of sufficiently diffuse wave fields generated by uncorrelated random sources are known to approximate deterministic Green's functions between the two points. This property is utilized increasingly for passive imaging and remote sensing of the environment. Here we show that the relation between the Green's functions and the noise cross-correlation function holds under much less restrictive conditions than previously thought. It can even hold when ambient noise sources have correlation ranges large compared to the wavelength. Admissible correlation ranges are limited from above by the size of the Fresnel zone at wave propagation between the points where noise cross correlation is evaluated.

  10. Distributed Fusion Filtering in Networked Systems with Random Measurement Matrices and Correlated Noises

    Directory of Open Access Journals (Sweden)

    Raquel Caballero-Águila

    2015-01-01

    Full Text Available The distributed fusion state estimation problem is addressed for sensor network systems with random state transition matrix and random measurement matrices, which provide a unified framework to consider some network-induced random phenomena. The process noise and all the sensor measurement noises are assumed to be one-step autocorrelated and different sensor noises are one-step cross-correlated; also, the process noise and each sensor measurement noise are two-step cross-correlated. These correlation assumptions cover many practical situations, where the classical independence hypothesis is not realistic. Using an innovation methodology, local least-squares linear filtering estimators are recursively obtained at each sensor. The distributed fusion method is then used to form the optimal matrix-weighted sum of these local filters according to the mean squared error criterion. A numerical simulation example shows the accuracy of the proposed distributed fusion filtering algorithm and illustrates some of the network-induced stochastic uncertainties that can be dealt with in the current system model, such as sensor gain degradation, missing measurements, and multiplicative noise.

  11. Transcranial Random Noise Stimulation (tRNS Shapes the Processing of Rapidly Changing Auditory Information

    Directory of Open Access Journals (Sweden)

    Katharina S. Rufener

    2017-06-01

    Full Text Available Neural oscillations in the gamma range are the dominant rhythmic activation pattern in the human auditory cortex. These gamma oscillations are functionally relevant for the processing of rapidly changing acoustic information in both speech and non-speech sounds. Accordingly, there is a tight link between the temporal resolution ability of the auditory system and inherent neural gamma oscillations. Transcranial random noise stimulation (tRNS has been demonstrated to specifically increase gamma oscillation in the human auditory cortex. However, neither the physiological mechanisms of tRNS nor the behavioral consequences of this intervention are completely understood. In the present study we stimulated the human auditory cortex bilaterally with tRNS while EEG was continuously measured. Modulations in the participants’ temporal and spectral resolution ability were investigated by means of a gap detection task and a pitch discrimination task. Compared to sham, auditory tRNS increased the detection rate for near-threshold stimuli in the temporal domain only, while no such effect was present for the discrimination of spectral features. Behavioral findings were paralleled by reduced peak latencies of the P50 and N1 component of the auditory event-related potentials (ERP indicating an impact on early sensory processing. The facilitating effect of tRNS was limited to the processing of near-threshold stimuli while stimuli clearly below and above the individual perception threshold were not affected by tRNS. This non-linear relationship between the signal-to-noise level of the presented stimuli and the effect of stimulation further qualifies stochastic resonance (SR as the underlying mechanism of tRNS on auditory processing. Our results demonstrate a tRNS related improvement in acoustic perception of time critical auditory information and, thus, provide further indices that auditory tRNS can amplify the resonance frequency of the auditory system.

  12. Scaling characteristics of one-dimensional fractional diffusion processes in the presence of power-law distributed random noise

    Science.gov (United States)

    Nezhadhaghighi, Mohsen Ghasemi

    2017-08-01

    Here, we present results of numerical simulations and the scaling characteristics of one-dimensional random fluctuations with heavy-tailed probability distribution functions. Assuming that the distribution function of the random fluctuations obeys Lévy statistics with a power-law scaling exponent, we investigate the fractional diffusion equation in the presence of μ -stable Lévy noise. We study the scaling properties of the global width and two-point correlation functions and then compare the analytical and numerical results for the growth exponent β and the roughness exponent α . We also investigate the fractional Fokker-Planck equation for heavy-tailed random fluctuations. We show that the fractional diffusion processes in the presence of μ -stable Lévy noise display special scaling properties in the probability distribution function (PDF). Finally, we numerically study the scaling properties of the heavy-tailed random fluctuations by using the diffusion entropy analysis. This method is based on the evaluation of the Shannon entropy of the PDF generated by the random fluctuations, rather than on the measurement of the global width of the process. We apply the diffusion entropy analysis to extract the growth exponent β and to confirm the validity of our numerical analysis.

  13. Fractional White-Noise Limit and Paraxial Approximation for Waves in Random Media

    Science.gov (United States)

    Gomez, Christophe; Pinaud, Olivier

    2017-12-01

    This work is devoted to the asymptotic analysis of high frequency wave propagation in random media with long-range dependence. We are interested in two asymptotic regimes, that we investigate simultaneously: the paraxial approximation, where the wave is collimated and propagates along a privileged direction of propagation, and the white-noise limit, where random fluctuations in the background are well approximated in a statistical sense by a fractional white noise. The fractional nature of the fluctuations is reminiscent of the long-range correlations in the underlying random medium. A typical physical setting is laser beam propagation in turbulent atmosphere. Starting from the high frequency wave equation with fast non-Gaussian random oscillations in the velocity field, we derive the fractional Itô-Schrödinger equation, that is, a Schrödinger equation with potential equal to a fractional white noise. The proof involves a fine analysis of the backscattering and of the coupling between the propagating and evanescent modes. Because of the long-range dependence, classical diffusion-approximation theorems for equations with random coefficients do not apply, and we therefore use moment techniques to study the convergence.

  14. Fractional White-Noise Limit and Paraxial Approximation for Waves in Random Media

    Science.gov (United States)

    Gomez, Christophe; Pinaud, Olivier

    2017-07-01

    This work is devoted to the asymptotic analysis of high frequency wave propagation in random media with long-range dependence. We are interested in two asymptotic regimes, that we investigate simultaneously: the paraxial approximation, where the wave is collimated and propagates along a privileged direction of propagation, and the white-noise limit, where random fluctuations in the background are well approximated in a statistical sense by a fractional white noise. The fractional nature of the fluctuations is reminiscent of the long-range correlations in the underlying random medium. A typical physical setting is laser beam propagation in turbulent atmosphere. Starting from the high frequency wave equation with fast non-Gaussian random oscillations in the velocity field, we derive the fractional Itô-Schrödinger equation, that is, a Schrödinger equation with potential equal to a fractional white noise. The proof involves a fine analysis of the backscattering and of the coupling between the propagating and evanescent modes. Because of the long-range dependence, classical diffusion-approximation theorems for equations with random coefficients do not apply, and we therefore use moment techniques to study the convergence.

  15. Random telegraph noise analysis in AlOx/WOy resistive switching memories

    Science.gov (United States)

    Zhang, Ye; Wu, Huaqiang; Wu, Minghao; Deng, Ning; Yu, Zhiping; Zhang, Jinyu; Qian, He

    2014-03-01

    In this Letter, the origins of current fluctuations of Al/AlOx/WOy/W bilayer resistive random access memory (RRAM) devices are investigated through detailed noise analysis. Random telegraph noise (RTN) measurements were performed on RRAMs with three different resistance states. An obvious RTN signal with 40.7% amplitude difference was found at high resistance state, and the trapping/de-trapping process leading to the RTN signal was studied in detail by extracting the trap energy from energy diagram. For median and low resistance states, the resistance fluctuations were 34.0% and 0.3%, respectively. To further study the RTN characteristics, the normalized power spectral density (PSD) was analyzed. It is found that, for one dominant-trap caused RTN phenomena, the normalized noise PSD behaves as 1/f 2 on the high resistance state; while for median and low resistance states, the noise follows 1/f rule, suggesting that the current fluctuations are associated with the envelop of multiple RTNs caused by traps located near/in the conductive filament. Based on the noise analyses in time and frequency domains, a conduction mechanism is proposed to describe the trap effects on the current fluctuations of different resistance states.

  16. Tracking random walk of individual domain walls in cylindrical nanomagnets with resistance noise.

    Science.gov (United States)

    Singh, Amrita; Mukhopadhyay, Soumik; Ghosh, Arindam

    2010-08-06

    The stochasticity of domain-wall (DW) motion in magnetic nanowires has been probed by measuring slow fluctuations, or noise, in electrical resistance at small magnetic fields. By controlled injection of DWs into isolated cylindrical nanowires of nickel, we have been able to track the motion of the DWs between the electrical leads by discrete steps in the resistance. Closer inspection of the time dependence of noise reveals a diffusive random walk of the DWs with a universal kinetic exponent. Our experiments outline a method with which electrical resistance is able to detect the kinetic state of the DWs inside the nanowires, which can be useful in DW-based memory designs.

  17. Random Number Simulations Reveal How Random Noise Affects the Measurements and Graphical Portrayals of Self-Assessed Competency

    Directory of Open Access Journals (Sweden)

    Edward Nuhfer

    2016-01-01

    Full Text Available Self-assessment measures of competency are blends of an authentic self-assessment signal that researchers seek to measure and random disorder or "noise" that accompanies that signal. In this study, we use random number simulations to explore how random noise affects critical aspects of self-assessment investigations: reliability, correlation, critical sample size, and the graphical representations of self-assessment data. We show that graphical conventions common in the self-assessment literature introduce artifacts that invite misinterpretation. Troublesome conventions include: (y minus x vs. (x scatterplots; (y minus x vs. (x column graphs aggregated as quantiles; line charts that display data aggregated as quantiles; and some histograms. Graphical conventions that generate minimal artifacts include scatterplots with a best-fit line that depict (y vs. (x measures (self-assessed competence vs. measured competence plotted by individual participant scores, and (y vs. (x scatterplots of collective average measures of all participants plotted item-by-item. This last graphic convention attenuates noise and improves the definition of the signal. To provide relevant comparisons across varied graphical conventions, we use a single dataset derived from paired measures of 1154 participants' self-assessed competence and demonstrated competence in science literacy. Our results show that different numerical approaches employed in investigating and describing self-assessment accuracy are not equally valid. By modeling this dataset with random numbers, we show how recognizing the varied expressions of randomness in self-assessment data can improve the validity of numeracy-based descriptions of self-assessment.

  18. The effect of presentation level on the Gaps-In-Noise (GIN) test.

    Science.gov (United States)

    Weihing, Jeffrey A; Musiek, Frank E; Shinn, Jennifer Brooke

    2007-02-01

    The Gaps-In-Noise (GIN) test is a new procedure used in the diagnosis of central auditory processing disorders. Performance on the GIN is recorded as approximate gap detection threshold and percent correct. In order to utilize the GIN test clinically, it is important to know how presentation level influences performance on the GIN. To this end, ten normal-hearing adults were administered the GIN at 5, 10, 15, 20, 25, 30, 35, and 50 dB SL with regard to threshold to GIN noise. Results indicated that performance for both the approximate gap detection threshold (A.th) and percent correct improved with increasing presentation level. Performance at 35 dB SL was not significantly different from the standard clinical presentation level (50 dB SL). Gaps that were between 5 and 8 msec in duration tended to show more variation across presentation levels. Although an influence of presentation level was noted, this influence should not be manifested at the standard clinical presentation level.

  19. Noise-correlation-time-mediated localization in random nonlinear dynamical systems

    CERN Document Server

    Cabrera, J L; De la Rubia, F J; Cabrera, Juan L.

    1999-01-01

    We investigate the behavior of the residence times density function for different nonlinear dynamical systems with limit cycle behavior and perturbed parametrically with a colored noise. We present evidence that underlying the stochastic resonancelike behavior with the noise correlation time, there is an effect of optimal localization of the system trajectories in the phase space. This phenomenon is observed in systems with different nonlinearities, suggesting a degree of universality.

  20. Effect of Acute Noise Exposure on Salivary Cortisol: A Randomized Controlled Trial.

    Science.gov (United States)

    Pouryaghoub, Gholamreza; Mehrdad, Ramin; Valipouri, Alireza

    2016-10-01

    Cardiovascular adverse effects are interesting aspects of occupational noise exposure. One possible mechanism of these effects is an alternation in hypothalamic-pituitary-adrenal axis. Our aim was to measure salivary cortisol response to relatively high-intensity noise exposure in a controlled randomized trial study. We exposed 50 male volunteers to 90 dBA noise for 20 minutes and compared their level of salivary cortisol with 50 non-exposed controls. Salivary samples obtained before and after exposure. Before intervention means (SD) salivary cortisol level were 3.24 (0.47)ng/ml and 3.25 (0.41)ng/ml for exposed and non-exposed groups respectively. Mean salivary cortisol level increased to 4.17 ng/mlafter intervention in exposure group. This increment was statistically significant (P=0.00). Mean salivary cortisol level of the non-exposed group had statistically non-significant decrement after this period (0.2 ng/ml). The difference between salivary cortisol level of non-exposed and exposed groups after the intervention was statistically significant. Noise exposure may affect the hypothalamic-pituitary-adrenal axis activity, and this may be one of the mechanisms of noise exposure cardiovascular effects.

  1. Ambient awareness: From random noise to digital closeness in online social networks

    OpenAIRE

    Levordashka, Ana; Utz, Sonja

    2016-01-01

    Ambient awareness refers to the awareness social media users develop of their online network in result of being constantly exposed to social information, such as microblogging updates. Although each individual bit of information can seem like random noise, their incessant reception can amass to a coherent representation of social others. Despite its growing popularity and important implications for social media research, ambient awareness on public social media has not been studied empiricall...

  2. A two-stage noise source identification technique based on a farfield random parametric array.

    Science.gov (United States)

    Bai, Mingsian R; Chen, You Siang; Lo, Yi-Yang

    2017-05-01

    A farfield random array is implemented for noise source identification. Microphone positions are optimized, with the aid of the simulated annealing method. A two-stage localization and separation algorithm is devised on the basis of the equivalent source method (ESM). In the localization stage, the active source regions are located by using the delay-and-sum method, followed by a parametric localization procedure, stochastic maximum likelihood algorithm. Multidimensional nonlinear optimization is exploited in the bearing estimation process. In the separation stage, source amplitudes are extracted by formulating an inverse problem based on the preceding source bearings identified. The number of equivalent sources is selected to be less than that of microphones to render an overdetermined problem which can be readily solved by using the Tikhonov regularization. Alternatively, the separation problem can be augmented into an underdetermined problem which can be solved by using the compressive sensing technique. Traditionally, farfield arrays only give a relative distribution of source field. However, by using the proposed method, the acoustic variables including sound pressure, particle velocity, sound intensity, and sound power can be calculated based on ESM. Numerical and experimental results of several objective and subjective tests are presented.

  3. Unsupervised reduction of random noise in complex data by a row-specific, sorted principal component-guided method

    Directory of Open Access Journals (Sweden)

    Katagiri Fumiaki

    2008-11-01

    Full Text Available Abstract Background Large biological data sets, such as expression profiles, benefit from reduction of random noise. Principal component (PC analysis has been used for this purpose, but it tends to remove small features as well as random noise. Results We interpreted the PCs as a mere signal-rich coordinate system and sorted the squared PC-coordinates of each row in descending order. The sorted squared PC-coordinates were compared with the distribution of the ordered squared random noise, and PC-coordinates for insignificant contributions were treated as random noise and nullified. The processed data were transformed back to the initial coordinates as noise-reduced data. To increase the sensitivity of signal capture and reduce the effects of stochastic noise, this procedure was applied to multiple small subsets of rows randomly sampled from a large data set, and the results corresponding to each row of the data set from multiple subsets were averaged. We call this procedure Row-specific, Sorted PRincipal component-guided Noise Reduction (RSPR-NR. Robust performance of RSPR-NR, measured by noise reduction and retention of small features, was demonstrated using simulated data sets. Furthermore, when applied to an actual expression profile data set, RSPR-NR preferentially increased the correlations between genes that share the same Gene Ontology terms, strongly suggesting reduction of random noise in the data set. Conclusion RSPR-NR is a robust random noise reduction method that retains small features well. It should be useful in improving the quality of large biological data sets.

  4. Olfactory Performance Can Be Influenced by the Presentation Order, Background Noise, and Positive Concurrent Feedback.

    Science.gov (United States)

    Walliczek-Dworschak, Ute; Pellegrino, Robert; Lee, Shangwa; Hummel, Cornelia; Hähner, Antje; Hummel, Thomas

    2016-10-01

    Sniffin' Sticks have become a popular procedure to measure overall olfactory functionality with 3 subtest: phenyl ethyl alcohol threshold test (T), discrimination (D), and identification (I). However, several procedural components specified by the original paper have not been tested nor has the impact of deviations been measured. The aim of the present work was to measure olfactory performance under modified testing procedures. First, the reverse order of subtests (IDT) was compared with more standard practices (TDI). Next, the possible impact of background noise and positive concurrent feedback were assessed. A total of 120 individuals participated in the study where the 3 conditional experiments, each involving 40 participants, were completed. Testing procedures that reversed the presentation order of subtests (I->D->T) scored a significantly lower overall TDI score than standard testing order with the threshold subtest being the most influenced. Additionally, nonverbal background noise lowered overall olfactory performance while concurrent feedback modulated threshold performance. These results emphasize the importance of testing parameters where olfactory perception and tasks may be modulated by adaptation and attentional distraction, respectively. This study helped furthermore to demonstrate that the investigated 3 deviations from the standard procedure revealed a significant impact on the performance outcome in olfactory assessment using the Sniffin' Sticks. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. Spatial Prediction Filtering of Acoustic Clutter and Random Noise in Medical Ultrasound Imaging.

    Science.gov (United States)

    Shin, Junseob; Huang, Lianjie

    2017-02-01

    One of the major challenges in array-based medical ultrasound imaging is the image quality degradation caused by sidelobes and off-axis clutter, which is an inherent limitation of the conventional delay-and-sum (DAS) beamforming operating on a finite aperture. Ultrasound image quality is further degraded in imaging applications involving strong tissue attenuation and/or low transmit power. In order to effectively suppress acoustic clutter from off-axis targets and random noise in a robust manner, we introduce in this paper a new adaptive filtering technique called frequency-space (F-X) prediction filtering or FXPF, which was first developed in seismic imaging for random noise attenuation. Seismologists developed FXPF based on the fact that linear and quasilinear events or wavefronts in the time-space (T-X) domain are manifested as a superposition of harmonics in the frequency-space (F-X) domain, which can be predicted using an auto-regressive (AR) model. We describe the FXPF technique as a spectral estimation or a direction-of-arrival problem, and explain why adaptation of this technique into medical ultrasound imaging is beneficial. We apply our new technique to simulated and tissue-mimicking phantom data. Our results demonstrate that FXPF achieves CNR improvements of 26% in simulated noise-free anechoic cyst, 109% in simulated anechoic cyst contaminated with random noise of 15 dB SNR, and 93% for experimental anechoic cyst from a custom-made tissue-mimicking phantom. Our findings suggest that FXPF is an effective technique to enhance ultrasound image contrast and has potential to improve the visualization of clinically important anatomical structures and diagnosis of diseased conditions.

  6. Impacts of regular and random noise on the behaviour, growth and development of larval Atlantic cod (Gadus morhua).

    Science.gov (United States)

    Nedelec, Sophie L; Simpson, Stephen D; Morley, Erica L; Nedelec, Brendan; Radford, Andrew N

    2015-10-22

    Anthropogenic noise impacts behaviour and physiology in many species, but responses could change with repeat exposures. As repeat exposures can vary in regularity, identifying regimes with less impact is important for regulation. We use a 16-day split-brood experiment to compare effects of regular and random acoustic noise (playbacks of recordings of ships), relative to ambient-noise controls, on behaviour, growth and development of larval Atlantic cod (Gadus morhua). Short-term noise caused startle responses in newly hatched fish, irrespective of rearing noise. Two days of both regular and random noise regimes reduced growth, while regular noise led to faster yolk sac use. After 16 days, growth in all three sound treatments converged, although fish exposed to regular noise had lower body width-length ratios. Larvae with lower body width-length ratios were easier to catch in a predator-avoidance experiment. Our results demonstrate that the timing of acoustic disturbances can impact survival-related measures during development. Much current work focuses on sound levels, but future studies should consider the role of noise regularity and its importance for noise management and mitigation measures. © 2015 The Authors.

  7. Phenomenological analysis of random telegraph noise in amorphous TiOx-based bipolar resistive switching random access memory devices.

    Science.gov (United States)

    Lee, Jung-Kyu; Lee, Ju-Wan; Bae, Jong-Ho; Park, Jinwon; Chung, Sung-Woong; Roh, Jae Sung; Hong, Sung-Joo; Lee, Jong-Ho

    2012-07-01

    As dimensions of resistive random access memories (RRAMs) devices continue to shrink, the low-frequency noise of nanoscale devices has become increasingly important in evaluating the device reliability. Thus, we investigated random telegraph noise (RTN) caused by capture and emission of an electron at traps. We physically analyzed capture and emission processes through systematic measurements of amorphous TiOx (alpha-TiOx)-based bipolar RRAMs. RTNs were observed during high-resistance state (HRS) in most devices. However, discrete switching behavior was scarcely observed in low-resistance state (LRS) as most of traps in the alpha-TiOx were filled with mobile ions such as O2- in LRS. The capture and emission processes of an electron at traps are largely divided into two groups: (1) both capture and emission processes are mainly affected by electric field; and (2) one of the capture and emission processes is only influenced by the thermal process. This paper provides fundamental physics required to understand the mechanism of RTNs in alpha-TiOx-based bipolar RRAMs.

  8. Kalman Filtering for Discrete Stochastic Systems with Multiplicative Noises and Random Two-Step Sensor Delays

    Directory of Open Access Journals (Sweden)

    Dongyan Chen

    2015-01-01

    Full Text Available This paper is concerned with the optimal Kalman filtering problem for a class of discrete stochastic systems with multiplicative noises and random two-step sensor delays. Three Bernoulli distributed random variables with known conditional probabilities are introduced to characterize the phenomena of the random two-step sensor delays which may happen during the data transmission. By using the state augmentation approach and innovation analysis technique, an optimal Kalman filter is constructed for the augmented system in the sense of the minimum mean square error (MMSE. Subsequently, the optimal Kalman filtering is derived for corresponding augmented system in initial instants. Finally, a simulation example is provided to demonstrate the feasibility and effectiveness of the proposed filtering method.

  9. Evaluation of noise propagation characteristics of compressors in tehran oil refinery center and presenting control methods.

    Science.gov (United States)

    Golmohammadi, Rostam; Monazzam, Mohammad Reza; Nourollahi, Maryam; Nezafat, Ali; Momen Bellah Fard, Samaneh

    2010-06-24

    The adverse effects of noise are well known and noise problems due to industrialization of communities are increasing over the time. Oil industries due to the process and nature of production; contain many noise sources such as compressors, turbines, and pumps, which cause excessive noise exposure. The objective of this study was to evaluate the noise characteristics of compressors in Tehran Oil Refinery and study on visible control measures.  To get to the appropriate control method, procedures such as basic theories, measuring sound parameters, frequency analysis, related diagrams and noise propagation schemes due to the measurement results, equivalent noise exposure level (L(eq(8h))) and exposure noise dose and  technical specification of compressors are considered in this paper. Considering field and analytical re-sults, module enclosure with particular specifications (like absorbent layer, specific wall, window and door design etc.) is predicted to be the best control method.  Calculation results of multiple layer density of the enclosure (W = 16.5 kg/m(2)) and needed density for the dominant frequency of the source (W = 12 kg/m(2)) demonstrated that the designed enclosure satisfies the goal. RESULTS of designing sandwich layers' module demonstrated that install-ing the designed enclosure causes 20 dB(A) reduction in total sound pres-sure level of the source's dominant frequency.

  10. Transcranial Random Noise Stimulation Does Not Enhance the Effects of Working Memory Training.

    Science.gov (United States)

    Holmes, Joni; Byrne, Elizabeth M; Gathercole, Susan E; Ewbank, Michael P

    2016-10-01

    Transcranial random noise stimulation (tRNS), a noninvasive brain stimulation technique, enhances the generalization and sustainability of gains following mathematical training. Here it is combined for the first time with working memory training in a double-blind randomized controlled trial. Adults completed 10 sessions of Cogmed Working Memory Training with either active tRNS or sham stimulation applied bilaterally to dorsolateral pFC. Training was associated with gains on both the training tasks and on untrained tests of working memory that shared overlapping processes with the training tasks, but not with improvements on working memory tasks with distinct processing demands or tests of other cognitive abilities (e.g., IQ, maths). There was no evidence that tRNS increased the magnitude or transfer of these gains. Thus, combining tRNS with Cogmed Working Memory Training provides no additional therapeutic value.

  11. Random exponential attractor for cocycle and application to non-autonomous stochastic lattice systems with multiplicative white noise

    Science.gov (United States)

    Zhou, Shengfan

    2017-08-01

    We first establish some sufficient conditions for constructing a random exponential attractor for a continuous cocycle on a separable Banach space and weighted spaces of infinite sequences. Then we apply our abstract result to study the existence of random exponential attractors for non-autonomous first order dissipative lattice dynamical systems with multiplicative white noise.

  12. Seismic random noise removal by delay-compensation time-frequency peak filtering

    Science.gov (United States)

    Yu, Pengjun; Li, Yue; Lin, Hongbo; Wu, Ning

    2017-06-01

    Over the past decade, there has been an increasing awareness of time-frequency peak filtering (TFPF) due to its outstanding performance in suppressing non-stationary and strong seismic random noise. The traditional approach based on time-windowing achieves local linearity and meets the unbiased estimation. However, the traditional TFPF (including the improved algorithms with alterable window lengths) could hardly relieve the contradiction between removing noise and recovering the seismic signal, and this situation is more obvious in wave crests and troughs, even for alterable window lengths (WL). To improve the efficiency of the algorithm, the following TFPF in the time-space domain is applied, such as in the Radon domain and radial trace domain. The time-space transforms obtain a reduced-frequency input to reduce the TFPF error and stretch the desired signal along a certain direction, therefore the time-space development brings an improvement by both enhancing reflection events and attenuating noise. It still proves limited in application because the direction should be matched as a straight line or quadratic curve. As a result, waveform distortion and false seismic events may appear when processing the complex stratum record. The main emphasis in this article is placed on the time-space TFPF applicable expansion. The reconstructed signal in delay-compensation TFPF, which is generated according to the similarity among the reflection events, overcomes the limitation of the direction curve fitting. Moreover, the reconstructed signal just meets the TFPF linearity unbiased estimation and integrates signal reservation with noise attenuation. Experiments on both the synthetic model and field data indicate that delay-compensation TFPF has a better performance over the conventional filtering algorithms.

  13. Random telegraph noise and resistance switching analysis of oxide based resistive memory.

    Science.gov (United States)

    Choi, Shinhyun; Yang, Yuchao; Lu, Wei

    2014-01-07

    Resistive random access memory (RRAM) devices (e.g."memristors") are widely believed to be a promising candidate for future memory and logic applications. Although excellent performance has been reported, the nature of resistance switching is still under extensive debate. In this study, we perform systematic investigation of the resistance switching mechanism in a TaOx based RRAM through detailed noise analysis, and show that the resistance switching from high-resistance to low-resistance is accompanied by a semiconductor-to-metal transition mediated by the accumulation of oxygen-vacancies in the conduction path. Specifically, pronounced random-telegraph noise (RTN) with values up to 25% was observed in the device high-resistance state (HRS) but not in the low-resistance state (LRS). Through time-domain and temperature dependent analysis, we show that the RTN effect shares the same origin as the resistive switching effects, and both can be traced to the (re)distribution of oxygen vacancies (VOs). From noise and transport analysis we further obtained the density of states and average distance of the VOs at different resistance states, and developed a unified model to explain the conduction in both the HRS and the LRS and account for the resistance switching effects in these devices. Significantly, it was found that even though the conduction channel area is larger in the HRS, during resistive switching a localized region gains significantly higher VO and dominates the conduction process. These findings reveal the complex dynamics involved during resistive switching and will help guide continued optimization in the design and operation of this important emerging device class.

  14. Innovative Data Capture and Presentation Techniques in Support of the EU Environmental Noise Directive

    OpenAIRE

    O'Riain, Gearoid; McCarthy, Tim

    2009-01-01

    The Environmental Protection Agency of Ireland (EPA) funded from 2006 to 2007 a research project to develop methodologies to meet data-related challenges arising under the European Union (EU) Environmental Noise Directive (END) (2002/49/EC) for Ireland. The research project sought to assess the role of advanced ground-based spatial video and also aerial digital photography in the creation of data required for suitably accurate noise modelling in road environments.

  15. 2D stochastic-integral models for characterizing random grain noise in titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Sabbagh, Harold A.; Murphy, R. Kim; Sabbagh, Elias H. [Victor Technologies, LLC, PO Box 7706, Bloomington, IN 47407-7706 (United States); Cherry, Matthew [University of Dayton Research Institute, 300 College Park Dr., Dayton, OH 45410 (United States); Pilchak, Adam; Knopp, Jeremy S.; Blodgett, Mark P. [Air Force Research Laboratory (AFRL/RXC), Wright Patterson AFB OH 45433-7817 (United States)

    2014-02-18

    We extend our previous work, in which we applied high-dimensional model representation (HDMR) and analysis of variance (ANOVA) concepts to the characterization of a metallic surface that has undergone a shot-peening treatment to reduce residual stresses, and has, therefore, become a random conductivity field. That example was treated as a onedimensional problem, because those were the only data available. In this study, we develop a more rigorous two-dimensional model for characterizing random, anisotropic grain noise in titanium alloys. Such a model is necessary if we are to accurately capture the 'clumping' of crystallites into long chains that appear during the processing of the metal into a finished product. The mathematical model starts with an application of the Karhunen-Loève (K-L) expansion for the random Euler angles, θ and φ, that characterize the orientation of each crystallite in the sample. The random orientation of each crystallite then defines the stochastic nature of the electrical conductivity tensor of the metal. We study two possible covariances, Gaussian and double-exponential, which are the kernel of the K-L integral equation, and find that the double-exponential appears to satisfy measurements more closely of the two. Results based on data from a Ti-7Al sample will be given, and further applications of HDMR and ANOVA will be discussed.

  16. Random resampling masks: a non-Bayesian one-shot strategy for noise reduction in digital holography.

    Science.gov (United States)

    Bianco, V; Paturzo, M; Memmolo, P; Finizio, A; Ferraro, P; Javidi, B

    2013-03-01

    Holographic imaging may become severely degraded by a mixture of speckle and incoherent additive noise. Bayesian approaches reduce the incoherent noise, but prior information is needed on the noise statistics. With no prior knowledge, one-shot reduction of noise is a highly desirable goal, as the recording process is simplified and made faster. Indeed, neither multiple acquisitions nor a complex setup are needed. So far, this result has been achieved at the cost of a deterministic resolution loss. Here we propose a fast non-Bayesian denoising method that avoids this trade-off by means of a numerical synthesis of a moving diffuser. In this way, only one single hologram is required as multiple uncorrelated reconstructions are provided by random complementary resampling masks. Experiments show a significant incoherent noise reduction, close to the theoretical improvement bound, resulting in image-contrast improvement. At the same time, we preserve the resolution of the unprocessed image.

  17. Polarization extinction ratio and polarization dependent intensity noise in long-pulse supercontinuum generation (Conference Presentation)

    DEFF Research Database (Denmark)

    Chin, Catherine; Engelsholm, Rasmus Dybbro; Moselund, Peter Morten

    2017-01-01

    polarization extinction ratios (PER) of over 10 dB. We experimentally demonstrate how the spectrally resolved polarization develops with increasing power and along the length of the nonlinear fiber. The experimental results are compared to numerical simulations of coupled polarization states mimicking...... the experimental conditions. Subsequently, a single-shot pulse-to-pulse polarization dependent relative intensity noise (PD-RIN) was measured and the noise characteristics were analyzed using long-tailed and rogue wave statistics. To do this, we used a range of 10 nm narrow bandpass filters (BPF) between 550 nm...

  18. Novel evidence that attributing affectively salient signal to random noise is associated with psychosis.

    Science.gov (United States)

    Catalan, Ana; Simons, Claudia J P; Bustamante, Sonia; Drukker, Marjan; Madrazo, Aranzazu; de Artaza, Maider Gonzalez; Gorostiza, Iñigo; van Os, Jim; Gonzalez-Torres, Miguel A

    2014-01-01

    We wished to replicate evidence that an experimental paradigm of speech illusions is associated with psychotic experiences. Fifty-four patients with a first episode of psychosis (FEP) and 150 healthy subjects were examined in an experimental paradigm assessing the presence of speech illusion in neutral white noise. Socio-demographic, cognitive function and family history data were collected. The Positive and Negative Syndrome Scale (PANSS) was administered in the patient group and the Structured Interview for Schizotypy-Revised (SIS-R), and the Community Assessment of Psychic Experiences (CAPE) in the control group. Patients had a much higher rate of speech illusions (33.3% versus 8.7%, ORadjusted: 5.1, 95% CI: 2.3-11.5), which was only partly explained by differences in IQ (ORadjusted: 3.4, 95% CI: 1.4-8.3). Differences were particularly marked for signals in random noise that were perceived as affectively salient (ORadjusted: 9.7, 95% CI: 1.8-53.9). Speech illusion tended to be associated with positive symptoms in patients (ORadjusted: 3.3, 95% CI: 0.9-11.6), particularly affectively salient illusions (ORadjusted: 8.3, 95% CI: 0.7-100.3). In controls, speech illusions were not associated with positive schizotypy (ORadjusted: 1.1, 95% CI: 0.3-3.4) or self-reported psychotic experiences (ORadjusted: 1.4, 95% CI: 0.4-4.6). Experimental paradigms indexing the tendency to detect affectively salient signals in noise may be used to identify liability to psychosis.

  19. Eigenvalues of Random Matrices with Isotropic Gaussian Noise and the Design of Diffusion Tensor Imaging Experiments*

    Science.gov (United States)

    Gasbarra, Dario; Pajevic, Sinisa; Basser, Peter J.

    2017-01-01

    Tensor-valued and matrix-valued measurements of different physical properties are increasingly available in material sciences and medical imaging applications. The eigenvalues and eigenvectors of such multivariate data provide novel and unique information, but at the cost of requiring a more complex statistical analysis. In this work we derive the distributions of eigenvalues and eigenvectors in the special but important case of m×m symmetric random matrices, D, observed with isotropic matrix-variate Gaussian noise. The properties of these distributions depend strongly on the symmetries of the mean tensor/matrix, D̄. When D̄ has repeated eigenvalues, the eigenvalues of D are not asymptotically Gaussian, and repulsion is observed between the eigenvalues corresponding to the same D̄ eigenspaces. We apply these results to diffusion tensor imaging (DTI), with m = 3, addressing an important problem of detecting the symmetries of the diffusion tensor, and seeking an experimental design that could potentially yield an isotropic Gaussian distribution. In the 3-dimensional case, when the mean tensor is spherically symmetric and the noise is Gaussian and isotropic, the asymptotic distribution of the first three eigenvalue central moment statistics is simple and can be used to test for isotropy. In order to apply such tests, we use quadrature rules of order t ≥ 4 with constant weights on the unit sphere to design a DTI-experiment with the property that isotropy of the underlying true tensor implies isotropy of the Fisher information. We also explain the potential implications of the methods using simulated DTI data with a Rician noise model. PMID:28989561

  20. Errors due to random noise in velocity measurement using incoherent-scatter radar

    Directory of Open Access Journals (Sweden)

    P. J. S. Williams

    Full Text Available The random-noise errors involved in measuring the Doppler shift of an 'incoherent-scatter' spectrum are predicted theoretically for all values of Te/Ti from 1.0 to 3.0. After correction has been made for the effects of convolution during transmission and reception and the additional errors introduced by subtracting the average of the background gates, the rms errors can be expressed by a simple semi-empirical formula. The observed errors are determined from a comparison of simultaneous EISCAT measurements using an identical pulse code on several adjacent frequencies. The plot of observed versus predicted error has a slope of 0.991 and a correlation coefficient of 99.3%. The prediction also agrees well with the mean of the error distribution reported by the standard EISCAT analysis programme.

  1. Errors due to random noise in velocity measurement using incoherent-scatter radar

    Directory of Open Access Journals (Sweden)

    P. J. S. Williams

    1996-12-01

    Full Text Available The random-noise errors involved in measuring the Doppler shift of an 'incoherent-scatter' spectrum are predicted theoretically for all values of Te/Ti from 1.0 to 3.0. After correction has been made for the effects of convolution during transmission and reception and the additional errors introduced by subtracting the average of the background gates, the rms errors can be expressed by a simple semi-empirical formula. The observed errors are determined from a comparison of simultaneous EISCAT measurements using an identical pulse code on several adjacent frequencies. The plot of observed versus predicted error has a slope of 0.991 and a correlation coefficient of 99.3%. The prediction also agrees well with the mean of the error distribution reported by the standard EISCAT analysis programme.

  2. Analysis of the levels of ambient noise present in the Colonia Auditorium (October 2001)

    Science.gov (United States)

    Jalisco, Zapopan; Palafox, Lourdes; Orozco, Martha; Rodriguez, Erika

    2002-11-01

    The study area is located in the city of Guadalajara, defined by: delimited in the north by the Gonzlez Gallo street; in the south by the Anillo Perifrico street; in the east by Avenida Mezquitan; and in the west by Avenida Alcalde. There were 38 measurement points outside the auditorium and 25 inside. A poll was conducted among the neighbors and visitors in both areas, getting 70 replies. Noise levels were between 41-101 dB(A) on the outside, average Leq on the outside was 64.5 dB(A), and inside was 80.15 dB(A). The conclusion is that the whole area is affected by traffic noise, as well by the huge number of visitors, the electric games, and the electric generators that supply energy to them. On the outside 21 points were above 65 dB(A), which means that 55% were above the average; on the inside, 100% were above 65 dB(A). Thus the neighbors are exposed to high noise levels due to the festivities during October. The biggest problem, however, is the noise exposure of the workers inside the auditorium, due to music, games, people, and electric generators.

  3. Single vacancy defect spectroscopy on HfO2 using random telegraph noise signals from scanning tunneling microscopy

    Science.gov (United States)

    Thamankar, R.; Raghavan, N.; Molina, J.; Puglisi, F. M.; O'Shea, S. J.; Shubhakar, K.; Larcher, L.; Pavan, P.; Padovani, A.; Pey, K. L.

    2016-02-01

    Random telegraph noise (RTN) measurements are typically carried out at the device level using standard probe station based electrical characterization setup, where the measured current represents a cumulative effect of the simultaneous response of electron capture/emission events at multiple oxygen vacancy defect (trap) sites. To better characterize the individual defects in the high-κ dielectric thin film, we propose and demonstrate here the measurement and analysis of RTN at the nanoscale using a room temperature scanning tunneling microscope setup, with an effective area of interaction of the probe tip that is as small as 10 nm in diameter. Two-level and multi-level RTN signals due to single and multiple defect locations (possibly dispersed in space and energy) are observed on 4 nm HfO2 thin films deposited on n-Si (100) substrate. The RTN signals are statistically analyzed using the Factorial Hidden Markov Model technique to decode the noise contribution of more than one defect (if any) and estimate the statistical parameters of each RTN signal (i.e., amplitude of fluctuation, capture and emission time constants). Observation of RTN at the nanoscale presents a new opportunity for studies on defect chemistry, single-defect kinetics and their stochastics in thin film dielectric materials. This method allows us to characterize the fast traps with time constants ranging in the millisecond to tens of seconds range.

  4. Unsteady Fast Random Particle Mesh method for efficient prediction of tonal and broadband noises of a centrifugal fan unit

    Directory of Open Access Journals (Sweden)

    Seung Heo

    2015-09-01

    Full Text Available In this study, efficient numerical method is proposed for predicting tonal and broadband noises of a centrifugal fan unit. The proposed method is based on Hybrid Computational Aero-Acoustic (H-CAA techniques combined with Unsteady Fast Random Particle Mesh (U-FRPM method. The U-FRPM method is developed by extending the FRPM method proposed by Ewert et al. and is utilized to synthesize turbulence flow field from unsteady RANS solutions. The H-CAA technique combined with U-FRPM method is applied to predict broadband as well as tonal noises of a centrifugal fan unit in a household refrigerator. Firstly, unsteady flow field driven by a rotating fan is computed by solving the RANS equations with Computational Fluid Dynamic (CFD techniques. Main source regions around the rotating fan are identified by examining the computed flow fields. Then, turbulence flow fields in the main source regions are synthesized by applying the U-FRPM method. The acoustic analogy is applied to model acoustic sources in the main source regions. Finally, the centrifugal fan noise is predicted by feeding the modeled acoustic sources into an acoustic solver based on the Boundary Element Method (BEM. The sound spectral levels predicted using the current numerical method show good agreements with the measured spectra at the Blade Pass Frequencies (BPFs as well as in the high frequency range. On the more, the present method enables quantitative assessment of relative contributions of identified source regions to the sound field by comparing predicted sound pressure spectrum due to modeled sources.

  5. The benefit obtained from visually displayed text from an automatic speech recognizer during listening to speech presented in noise

    NARCIS (Netherlands)

    Zekveld, A.A.; Kramer, S.E.; Kessens, J.M.; Vlaming, M.S.M.G.; Houtgast, T.

    2008-01-01

    OBJECTIVES: The aim of this study was to evaluate the benefit that listeners obtain from visually presented output from an automatic speech recognition (ASR) system during listening to speech in noise. DESIGN: Auditory-alone and audiovisual speech reception thresholds (SRTs) were measured. The SRT

  6. Speech production in amplitude-modulated noise

    DEFF Research Database (Denmark)

    Macdonald, Ewen N; Raufer, Stefan

    2013-01-01

    the consequences of temporally fluctuating noise. In the present study, 20 talkers produced speech in a variety of noise conditions, including both steady-state and amplitude-modulated white noise. While listening to noise over headphones, talkers produced randomly generated five word sentences. Similar...... to previous studies, talkers raised the level of their voice in steady-state noise. While talkers also increased the level of their voice in amplitude-modulated noise, the increase was not as large as that observed in steady-state noise. Importantly, for the 2 and 4 Hz amplitude-modulated noise conditions...

  7. Noise Gating Solar Images

    Science.gov (United States)

    DeForest, Craig; Seaton, Daniel B.; Darnell, John A.

    2017-08-01

    I present and demonstrate a new, general purpose post-processing technique, "3D noise gating", that can reduce image noise by an order of magnitude or more without effective loss of spatial or temporal resolution in typical solar applications.Nearly all scientific images are, ultimately, limited by noise. Noise can be direct Poisson "shot noise" from photon counting effects, or introduced by other means such as detector read noise. Noise is typically represented as a random variable (perhaps with location- or image-dependent characteristics) that is sampled once per pixel or once per resolution element of an image sequence. Noise limits many aspects of image analysis, including photometry, spatiotemporal resolution, feature identification, morphology extraction, and background modeling and separation.Identifying and separating noise from image signal is difficult. The common practice of blurring in space and/or time works because most image "signal" is concentrated in the low Fourier components of an image, while noise is evenly distributed. Blurring in space and/or time attenuates the high spatial and temporal frequencies, reducing noise at the expense of also attenuating image detail. Noise-gating exploits the same property -- "coherence" -- that we use to identify features in images, to separate image features from noise.Processing image sequences through 3-D noise gating results in spectacular (more than 10x) improvements in signal-to-noise ratio, while not blurring bright, resolved features in either space or time. This improves most types of image analysis, including feature identification, time sequence extraction, absolute and relative photometry (including differential emission measure analysis), feature tracking, computer vision, correlation tracking, background modeling, cross-scale analysis, visual display/presentation, and image compression.I will introduce noise gating, describe the method, and show examples from several instruments (including SDO

  8. Mittag-Leffler noise induced stochastic resonance in a generalized Langevin equation with random inherent frequency

    Science.gov (United States)

    He, Guitian; Guo, Dali; Tian, Yan; Li, Tiejun; Luo, Maokang

    2017-10-01

    The generalized stochastic resonance (GSR) and the bona fide stochastic resonance (SR) in a generalized Langevin equation driven by a periodic signal, multiplicative noise and Mittag-Leffler noise are extensively investigated. The expression of the frequency spectrum of the Mittag-Leffler noise is studied. Using the Shapiro-Loginov formula and Laplace transformation technique, the exact expressions of the output amplitude gain and the signal-to-noise ratio are obtained. The simulation results turn out that the output amplitude gain and the signal-to-noise ratio are non-monotonic functions of the characteristics of noise parameters and system parameters. Especially, the influence of the memory exponent and memory time of Mittag-Leffler noise could induce the GSR phenomenon. The influence of the driving frequency could induce the bona fide stochastic resonance. It is found that the system with fractional memory exponent could be more easily induced SR phenomenon than the system with integer memory exponent.

  9. Auditory cortical activity in normal hearing subjects to consonant vowels presented in quiet and in noise.

    Science.gov (United States)

    Dimitrijevic, Andrew; Pratt, Hillel; Starr, Arnold

    2013-06-01

    Compare brain potentials to consonant vowels (CVs) as a function of both voice onset times (VOTs) and consonant position; initial (CV) versus second (VCV). Auditory cortical potentials (N100, P200, N200, and a late slow negativity, (SN) were recorded from scalp electrodes in twelve normal hearing subjects to consonant vowels in initial position (CVs: /du/ and /tu/), in second position (VCVs: /udu/ and /utu/), and to vowels alone (V: /u/) and paired (VVs: /uu/) separated in time to simulate consonant voice onset times (VOTs). CVs evoked "acoustic onset" N100s of similar latency but larger amplitudes to /du/ than /tu/. CVs preceded by a vowel (VCVs) evoked "acoustic change" N100s with longer latencies to /utu/ than /udu/. Their absolute latency difference was less than the corresponding VOT difference. The SN following N100 to VCVs was larger to /utu/ than /udu/. Paired vowels (/uu/) separated by intervals corresponding to consonant VOTs evoked N100s with latency differences equal to the simulated VOT differences and SNs of similar amplitudes. Noise masking resulted in VCV N100 latency differences that were now equal to consonant VOT differences. Brain activations by CVs, VCVs, and VVs were maximal in right temporal lobe. Auditory cortical activities to CVs are sensitive to: (1) position of the CV in the utterance; (2) VOTs of consonants; and (3) noise masking. VOTs of stop consonants affect auditory cortical activities differently as a function of the position of the consonant in the utterance. Copyright © 2012 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  10. Polarization extinction ratio and polarization dependent intensity noise in long-pulse supercontinuum generation (Conference Presentation)

    Science.gov (United States)

    Chin, Catherine; Dybbro Engelsholm, Rasmus; Moselund, Peter Morten; Feuchter, Thomas; Leick, Lasse; Podoleanu, Adrian; Bang, Ole

    2017-02-01

    We investigate the polarization of supercontinuum generated in nominally non-birefringent silica photonic crystal fibers over the entire spectrum of the source (450-2400 nm). We demonstrate that the degree of polarization varies over the spectrum but that some parts of the spectrum show stable polarization extinction ratios (PER) of over 10 dB. We experimentally demonstrate how the spectrally resolved polarization develops with increasing power and along the length of the nonlinear fiber. The experimental results are compared to numerical simulations of coupled polarization states mimicking the experimental conditions. Subsequently, a single-shot pulse-to-pulse polarization dependent relative intensity noise (PD-RIN) was measured and the noise characteristics were analyzed using long-tailed and rogue wave statistics. To do this, we used a range of 10 nm narrow bandpass filters (BPF) between 550 nm to 2200 nm, and fast photo detectors, to record 800 consecutive pulses. Peaks from these pulses are first extracted, then distribution of their pulse height histogram (PHH) is constructed. Analysis using higher-order moments about the mean (variance, skewness and kurtosis) showed that: (1) around the pump wavelength of 1064nm, the PD-RIN is lowest, PHH exhibits a Gaussian distribution, and higher order moments are zero, (2) further away from pump, PD-RIN increases in parabolic fashion, PHH follows a left-skewed long-tailed Gamma distribution, and higher-order moments increase. Spectrally, the difference of the PD-RIN in the two orthogonal axes increases with PER.

  11. Noise-induced hearing loss in randomly selected New York dairy farmers.

    Science.gov (United States)

    May, J J; Marvel, M; Regan, M; Marvel, L H; Pratt, D S

    1990-01-01

    To understand better the effects of noise levels associated with dairy farming, we randomly selected 49 full-time dairy farmers from an established cohort. Medical and occupational histories were taken and standard audiometric testing was done. Forty-six males (94%) and three females (6%) with a mean age of 43.5 (+/- 13) years and an average of 29.4 (+/- 14) years in farming were tested. Pure Tone Average thresholds (PTA4) at 0.5, 1.0, 2.0, and 3.0 kHz plus High Frequency Average thresholds (HFA3) at 3.0, 4.0, and 6.0 kHz were calculated. Subjects with a loss of greater than or equal to 20 db in either ear were considered abnormal. Eighteen subjects (37%) had abnormal PTA4S and 32 (65%) abnormal HFA3S. The left ear was more severely affected in both groups (p less than or equal to .05, t-test). Significant associations were found between hearing loss and years worked (odds ratio 4.1, r = .53) and age (odds ratio 4.1, r = .59). No association could be found between hearing loss and measles; mumps; previous ear infections; or use of power tools, guns, motorcycles, snowmobiles, or stereo headphones. Our data suggest that among farmers, substantial hearing loss occurs especially in the high-frequency ranges. Presbycusis is an important confounding variable.

  12. Ambient awareness: From random noise to digital closeness in online social networks.

    Science.gov (United States)

    Levordashka, Ana; Utz, Sonja

    2016-07-01

    Ambient awareness refers to the awareness social media users develop of their online network in result of being constantly exposed to social information, such as microblogging updates. Although each individual bit of information can seem like random noise, their incessant reception can amass to a coherent representation of social others. Despite its growing popularity and important implications for social media research, ambient awareness on public social media has not been studied empirically. We provide evidence for the occurrence of ambient awareness and examine key questions related to its content and functions. A diverse sample of participants reported experiencing awareness, both as a general feeling towards their network as a whole, and as knowledge of individual members of the network, whom they had not met in real life. Our results indicate that ambient awareness can develop peripherally, from fragmented information and in the relative absence of extensive one-to-one communication. We report the effects of demographics, media use, and network variables and discuss the implications of ambient awareness for relational and informational processes online.

  13. Influence of Bandstructure Effects on the Single-Charge-Induced Random Telegraphic Noise in Nanoscale FETs

    Science.gov (United States)

    Islam, Sharnali; Ahmed, Shaikh

    2010-03-01

    Numerical simulations have been carried out to study the single-charge-induced random telegraphic noise in nanoscale field-effect transistors. A three-dimensional Monte Carlo device simulator has been developed and used in this work. Quantum effects have been accounted for via a parameter-free effective potential scheme that is based on a perturbation theory around thermodynamic equilibrium where the size of the electron depends upon its energy. For better accuracy, bandstructure parameters (bandgap, effective masses, and density of states) have been computed via a 20-band sp3d5s* tight-binding scheme. To treat full Coulomb interactions properly, two real-space molecular dynamics schemes have been implemented. Also, necessary event-biasing algorithms have been used that, while enhancing the statistics, results in a faster convergence in the channel current. The study confirms that, due to the presence of single channel charges, both the electrostatics (carrier density) and dynamics (mobility) get perturbed and, therefore, play important roles in determining the magnitude of the current fluctuations. The relative impact depends on an intricate interplay of device size, geometry, crystal direction, gate bias, temperature, and energetic and spatial location of the trap.

  14. Physical-layer security analysis of PSK quantum-noise randomized cipher in optically amplified links

    Science.gov (United States)

    Jiao, Haisong; Pu, Tao; Xiang, Peng; Zheng, Jilin; Fang, Tao; Zhu, Huatao

    2017-08-01

    The quantitative security of quantum-noise randomized cipher (QNRC) in optically amplified links is analyzed from the perspective of physical-layer advantage. Establishing the wire-tap channel models for both key and data, we derive the general expressions of secrecy capacities for the key against ciphertext-only attack and known-plaintext attack, and that for the data, which serve as the basic performance metrics. Further, the maximal achievable secrecy rate of the system is proposed, under which secrecy of both the key and data is guaranteed. Based on the same framework, the secrecy capacities of various cases can be assessed and compared. The results indicate perfect secrecy is potentially achievable for data transmission, and an elementary principle of setting proper number of photons and bases is given to ensure the maximal data secrecy capacity. But the key security is asymptotically perfect, which tends to be the main constraint of systemic maximal secrecy rate. Moreover, by adopting cascaded optical amplification, QNRC can realize long-haul transmission with secure rate up to Gb/s, which is orders of magnitude higher than the perfect secrecy rates of other encryption systems.

  15. Dynamical decoupling of local transverse random telegraph noise in a two-qubit gate

    Science.gov (United States)

    D'Arrigo, A.; Falci, G.; Paladino, E.

    2015-10-01

    Achieving high-fidelity universal two-qubit gates is a central requisite of any implementation of quantum information processing. The presence of spurious fluctuators of various physical origin represents a limiting factor for superconducting nanodevices. Operating qubits at optimal points, where the qubit-fluctuator interaction is transverse with respect to the single qubit Hamiltonian, considerably improved single qubit gates. Further enhancement has been achieved by dynamical decoupling (DD). In this article we investigate DD of transverse random telegraph noise acting locally on each of the qubits forming an entangling gate. Our analysis is based on the exact numerical solution of the stochastic Schrödinger equation. We evaluate the gate error under local periodic, Carr-Purcell and Uhrig DD sequences. We find that a threshold value of the number, n, of pulses exists above which the gate error decreases with a sequence-specific power-law dependence on n. Below threshold, DD may even increase the error with respect to the unconditioned evolution, a behaviour reminiscent of the anti-Zeno effect.

  16. Hydrogen-dependent low frequency noise and its physical mechanism of HfO2 resistance change random access memory

    Science.gov (United States)

    Chen, Y. Q.; Liu, X.; Liu, Y.; Peng, C.; Fang, W. X.; En, Y. F.; Huang, Y.

    2017-12-01

    The effect of hydrogen on low frequency noise characteristics of HfO2 resistance change random access memories (RRAMs) was investigated in this paper. The experimental results show that HfO2 RRAMs after hydrogen treatment take on the better uniformity of switch characteristics and the conduction enhancement behavior. Furthermore, it was found that the low frequency noise characteristics of the HfO2 RRAMs was significantly impacted by the hydrogen treatment, and at three kinds of typical resistance states, the low frequency noises of the HfO2 RRAMs after hydrogen treatment are larger than those of the fresh HfO2 RRAMs. The mechanism could be attributed to H induced oxygen vacancies, which serve as the additional traps for conduction due to the trap-assisted tunneling process. This will result in more random trap/detrap processes in the conducting filament, which gives rise to the larger low frequency noise in the HfO2 RRAMs. The results of this study may be useful in the design and application of HfO2 RRAMs.

  17. Critical ratios in harbor porpoises (Phocoena phocoena) for tonal signals between 0.315 and 150 kHz in random Gaussian white noise.

    Science.gov (United States)

    Kastelein, Ronald A; Wensveen, Paul J; Hoek, Lean; Au, Whitlow W L; Terhune, John M; de Jong, Christ A F

    2009-09-01

    A psychoacoustic behavioral technique was used to determine the critical ratios (CRs) of two harbor porpoises for tonal signals with frequencies between 0.315 and 150 kHz, in random Gaussian white noise. The masked 50% detection hearing thresholds were measured using a "go/no-go" response paradigm and an up-down staircase psychometric method. CRs were determined at one masking noise level for each test frequency and were similar in both animals. For signals between 0.315 and 4 kHz, the CRs were relatively constant at around 18 dB. Between 4 and 150 kHz the CR increased gradually from 18 to 39 dB ( approximately 3.3 dB/octave). Generally harbor porpoises can detect tonal signals in Gaussian white noise slightly better than most odontocetes tested so far. By combining the mean CRs found in the present study with the spectrum level of the background noise levels at sea, the basic audiogram, and the directivity index, the detection threshold levels of harbor porpoises for tonal signals in various sea states can be calculated.

  18. Noise prevention

    Science.gov (United States)

    Methods for noise abatement are discussed. Noise nuisance, types of noise (continuous, fluctuating, intermittent, pulsed), and types of noise abatement (absorption, vibration damping, isolation) are defined. Rockwool panels, industrial ceiling panels, baffles, acoustic foam panels, vibration dampers, acoustic mats, sandwich panels, isolating cabins and walls, ear protectors, and curtains are presented.

  19. Seismic random noise attenuation by time-frequency peak filtering based on joint time-frequency distribution

    Science.gov (United States)

    Zhang, Chao; Lin, Hong-bo; Li, Yue; Yang, Bao-jun

    2013-09-01

    Time-Frequency Peak Filtering (TFPF) is an effective method to eliminate pervasive random noise when seismic signals are analyzed. In conventional TFPF, the pseudo Wigner-Ville distribution (PWVD) is used for estimating instantaneous frequency (IF), but is sensitive to noise interferences that mask the borderline between signal and noise and detract the energy concentration on the IF curve. This leads to the deviation of the peaks of the pseudo Wigner-Ville distribution from the instantaneous frequency, which is the cause of undesirable lateral oscillations as well as of amplitude attenuation of the highly varying seismic signal, and ultimately of the biased seismic signal. With the purpose to overcome greatly these drawbacks and increase the signal-to-noise ratio, we propose in this paper a TFPF refinement that is based upon the joint time-frequency distribution (JTFD). The joint time-frequency distribution is obtained by the combination of the PWVD and smooth PWVD (SPWVD). First we use SPWVD to generate a broad time-frequency area of the signal. Then this area is filtered with a step function to remove some divergent time-frequency points. Finally, the joint time-frequency distribution JTFD is obtained from PWVD weighted by this filtered distribution. The objective pursued with all these operations is to reduce the effects of the interferences and enhance the energy concentration around the IF of the signal in the time-frequency domain. Experiments with synthetic and real seismic data demonstrate that TFPF based on the joint time-frequency distribution can effectively suppress strong random noise and preserve events of interest.

  20. Transcranial random noise stimulation mitigates increased difficulty in an arithmetic learning task.

    Science.gov (United States)

    Popescu, Tudor; Krause, Beatrix; Terhune, Devin B; Twose, Olivia; Page, Thomas; Humphreys, Glyn; Cohen Kadosh, Roi

    2016-01-29

    Proficiency in arithmetic learning can be achieved by using a multitude of strategies, the most salient of which are procedural learning (applying a certain set of computations) and rote learning (direct retrieval from long-term memory). Here we investigated the effect of transcranial random noise stimulation (tRNS), a non-invasive brain stimulation method previously shown to enhance cognitive training, on both types of learning in a 5-day sham-controlled training study, under two conditions of task difficulty, defined in terms of item repetition. On the basis of previous research implicating the prefrontal and posterior parietal cortex in early and late stages of arithmetic learning, respectively, sham-controlled tRNS was applied to bilateral prefrontal cortex for the first 3 days and to the posterior parietal cortex for the last 2 days of a 5-day training phase. The training involved learning to solve arithmetic problems by applying a calculation algorithm; both trained and untrained problems were used in a brief testing phase at the end of the training phase. Task difficulty was manipulated between subjects by using either a large ("easy" condition) or a small ("difficult" condition) number of repetition of problems during training. Measures of attention and working memory were acquired before and after the training phase. As compared to sham, participants in the tRNS condition displayed faster reaction times and increased learning rate during the training phase; as well as faster reaction times for both trained and untrained (new) problems, which indicated a transfer effect after the end of training. All stimulation effects reached significance only in the "difficult" condition when number of repetition was lower. There were no transfer effects of tRNS on attention or working memory. The results support the view that tRNS can produce specific facilitative effects on numerical cognition--specifically, on arithmetic learning. They also highlight the importance of

  1. 1/f Noise and multifractality from bristlecone pine growth explained by the statistical convergence of random data

    Science.gov (United States)

    Kendal, Wayne S.

    2017-02-01

    Tree-ring growth records from bristlecone pines reveal an irregular pattern of fluctuations that have been linked to climatic change but otherwise have remained poorly understood. We find within these records evidence for a temporally related variance to mean power law, 1/f noise and multifractality that empirically resembles a fractal stochastic process and could be attributed to self-organized criticality. These growth records, however, also conformed to a non-Gaussian statistical distribution (the Tweedie compound Poisson distribution) characterized by an inherent variance to mean power law, that by itself implies 1/f noise. This distribution has a fundamental role in statistical theory as a focus of convergence for many types of random data, much like the Gaussian distribution has with the central limit theorem. The growth records were also multifractal, with the dimensional exponent of the Tweedie distribution critically balanced near the transition point between fractal stochastic processes and gamma distributed data, possibly consequent to a related convergence effect. Non-Gaussian random systems, like those related to bristlecone pine tree growth, may express 1/f noise and multifractality through mathematical convergence effects alone, without the dynamical assumptions of self-organized criticality.

  2. The clinical and biomechanical effects of subthreshold random noise on the plantar surface of the foot in diabetic patients and elder people: A systematic review.

    Science.gov (United States)

    Bagherzadeh Cham, Masumeh; Mohseni-Bandpei, Mohammad Ali; Bahramizadeh, Mahmood; Kalbasi, Saeed; Biglarian, Akbar

    2016-12-01

    Central nervous system receives information from foot mechanoreceptors in order to control balance and perform movement tasks. Subthreshold random noise seems to improve sensitivity of the cutaneous mechanoreceptor. The purpose of this study was to systematically review published evidence conducted to evaluate the clinical and biomechanical effects of subthreshold random noise on the plantar surface of the foot in diabetic patients and elder people. Systematic review. A literature search was performed in PubMed, Scopus, ScienceDirect, Web of Knowledge, CINAHL, and EMBASE databases based on population, intervention, comparison, outcomes, and study method. Quality of studies was assessed using the methodological quality assessment tool, using Physiotherapy Evidence Database scale. In all, 11 studies were selected for final evaluation based on inclusion criteria. Five studies evaluated the effects of subthreshold random noise in diabetic patients and six in elder people. In seven studies, biomechanical (balance and gait parameters) effects and in four studies clinical (pressure and vibration sensations) effects of subthreshold random noise were investigated. All reviewed studies were scored fair (2) to good (9) quality in terms of methodological quality assessment using Physiotherapy Evidence Database scale. The results indicated that subthreshold random noise improves balance and sensation in diabetic patients and elder people. Also gait variables can be improved in elder people with subthreshold random noise. However, further well-designed studies are needed. The previous studies reported that subthreshold random noise may improve gait, balance, and sensation, but more studies are needed to evaluate the long-term effect of subthreshold random noise in shoe or insole for daily living tasks in diabetic patients and elder people. © The International Society for Prosthetics and Orthotics 2016.

  3. Statistical properties of a filtered Poisson process with additive random noise: Distributions, correlations and moment estimation

    CERN Document Server

    Theodorsen, Audun; Rypdal, Martin

    2016-01-01

    The filtered Poisson process is often used as a reference model for intermittent fluctuations in physical systems. Here, this process is extended by adding a noise term, either as a purely additive term to the process or as a dynamical term in a stochastic differential equation. The moments, probability density function, auto- correlation function and power spectral density are derived and used to compare the effects of the different noise terms. Monte-Carlo studies of synthetic time series are used to investigate the accuracy of parameter estimation and to identify methods for separating the noise types. It is shown that the probability density function and the three lowest moments provide accurate estimations of the parameters, but are unable to separate the noise types. The auto-correlation function and the power spectral density also provide methods for estimating the model parameters, as well as being capable of determining the noise type. The number of times the signal passes a prescribed threshold in t...

  4. Generalized randomly amplified linear system driven by gaussian noises: extreme heavy tail and algebraic correlation decay in plasma turbulence.

    Science.gov (United States)

    Steinbrecher, György; Weyssow, B

    2004-03-26

    The extreme heavy tail and the power-law decay of the turbulent flux correlation observed in hot magnetically confined plasmas are modeled by a system of coupled Langevin equations describing a continuous time linear randomly amplified stochastic process where the amplification factor is driven by a superposition of colored noises which, in a suitable limit, generate a fractional Brownian motion. An exact analytical formula for the power-law tail exponent beta is derived. The extremely small value of the heavy tail exponent and the power-law distribution of laminar times also found experimentally are obtained, in a robust manner, for a wide range of input values, as a consequence of the (asymptotic) self-similarity property of the noise spectrum. As a by-product, a new representation of the persistent fractional Brownian motion is obtained.

  5. Effectiveness of Earplugs in Preventing Recreational Noise-Induced Hearing Loss: A Randomized Clinical Trial.

    Science.gov (United States)

    Ramakers, Geerte G J; Kraaijenga, Véronique J C; Cattani, Guido; van Zanten, Gijsbert A; Grolman, Wilko

    2016-06-01

    ). Newly induced tinnitus following sound exposure occurred in 3 of the 25 participants (12%) in the earplug group vs 10 of 25 (40%) in the unprotected group (difference, 28%; 95% CI, 3.6%-49.0%; P = .02). Earplug use is effective in preventing temporary hearing loss after loud music exposure. The present randomized clinical trial adds proof to the scarce evidence and knowledge on this topic, which is a growing global problem. trialregister.nl Identifier: NTR5401.

  6. Effect of signal-temporal uncertainty in children and adults: tone detection in noise or a random-frequency masker.

    Science.gov (United States)

    Bonino, Angela Yarnell; Leibold, Lori J; Buss, Emily

    2013-12-01

    A cue indicating when in time to listen can improve adults' tone detection thresholds, particularly for conditions that produce substantial informational masking. The purpose of this study was to determine if 5- to 13-yr-old children likewise benefit from a light cue indicating when in time to listen for a masked pure-tone signal. Each listener was tested in one of two continuous maskers: Broadband noise (low informational masking) or a random-frequency, two-tone masker (high informational masking). Using a single-interval method of constant stimuli, detection thresholds were measured for two temporal conditions: (1) Temporally-defined, with the listening interval defined by a light cue, and (2) temporally-uncertain, with no light cue. Thresholds estimated from psychometric functions fitted to the data indicated that children and adults benefited to the same degree from the visual cue. Across listeners, the average benefit of a defined listening interval was 1.8 dB in the broadband noise and 8.6 dB in the random-frequency, two-tone masker. Thus, the benefit of knowing when in time to listen was more robust for conditions believed to be dominated by informational masking. An unexpected finding of this study was that children's thresholds were comparable to adults' in the random-frequency, two-tone masker.

  7. Optical noise and temporal coherence

    Science.gov (United States)

    Chavel, P.

    1980-08-01

    Previous articles have been devoted to the study of optical noise as a function of spatial coherence. The present one completes this study by considering temporal coherence. Noise arising from defects in the pupil plane and affecting the high spatial frequencies of an image is notably reduced by white-light illumination. Temporal coherence has little effect on noise arising from defects in the object plane. However, impulse noise due to small isolated defects is reduced in size. Physical arguments are presented to explain these phenomena and a mathematical study of partially coherent imaging in the presence of random defects is given.

  8. Efficacy of low-level laser therapy in the management of tinnitus due to noise-induced hearing loss: a double-blind randomized clinical trial.

    Science.gov (United States)

    Mollasadeghi, Abolfazl; Mirmohammadi, Seyyed Jalil; Mehrparvar, Amir Houshang; Davari, Mohammad Hossein; Shokouh, Pedram; Mostaghaci, Mehrdad; Baradaranfar, Mohammad Hossein; Bahaloo, Maryam

    2013-01-01

    Background. Several remedial modalities for the treatment of tinnitus have been proposed, but an effective standard treatment is still to be confirmed. In the present study, we aimed to evaluate the effect of low-level laser therapy on tinnitus accompanied by noise-induced hearing loss. Methods. This was a double-blind randomized clinical trial on subjects suffering from tinnitus accompanied by noise-induced hearing loss. The study intervention was 20 sessions of low-level laser therapy every other day, 20 minutes each session. Tinnitus was assessed by three methods (visual analog scale, tinnitus handicap inventory, and tinnitus loudness) at baseline, immediately and 3 months after the intervention. Results. All subjects were male workers with age range of 30-51 years. The mean tinnitus duration was 1.85 ± 0.78 years. All three measurement methods have shown improved values after laser therapy compared with the placebo both immediately and 3 months after treatment. Laser therapy revealed a U-shaped efficacy throughout the course of follow-up. Nonresponse rate of the intervention was 57% and 70% in the two assessment time points, respectively. Conclusion. This study found low-level laser therapy to be effective in alleviating tinnitus in patients with noise-induced hearing loss, although this effect has faded after 3 months of follow-up. This trial is registered with the Australian New Zealand clinical trials registry with identifier ACTRN12612000455864).

  9. Quasi-Coherent Noise Jamming to LFM Radar Based on Pseudo-random Sequence Phase-modulation

    Directory of Open Access Journals (Sweden)

    N. Tai

    2015-12-01

    Full Text Available A novel quasi-coherent noise jamming method is proposed against linear frequency modulation (LFM signal and pulse compression radar. Based on the structure of digital radio frequency memory (DRFM, the jamming signal is acquired by the pseudo-random sequence phase-modulation of sampled radar signal. The characteristic of jamming signal in time domain and frequency domain is analyzed in detail. Results of ambiguity function indicate that the blanket jamming effect along the range direction will be formed when jamming signal passes through the matched filter. By flexible controlling the parameters of interrupted-sampling pulse and pseudo-random sequence, different covering distances and jamming effects will be achieved. When the jamming power is equivalent, this jamming obtains higher process gain compared with non-coherent jamming. The jamming signal enhances the detection threshold and the real target avoids being detected. Simulation results and circuit engineering implementation validate that the jamming signal covers real target effectively.

  10. Computation of covex bounds for present value functions with random payments

    NARCIS (Netherlands)

    Ahcan, A.; Darkiewicz, G.; Goovaerts, M.J.; Hoedemakers, T.

    2006-01-01

    In this contribution we study the distribution of the present value function of a series of random payments in a stochastic financial environment. Such distributions occur naturally in a wide range of applications within fields of insurance and finance. We obtain accurate approximations by

  11. Combined influence of CT random noise and HU-RSP calibration curve nonlinearities on proton range systematic errors

    Science.gov (United States)

    Brousmiche, S.; Souris, K.; Orban de Xivry, J.; Lee, J. A.; Macq, B.; Seco, J.

    2017-11-01

    Proton range random and systematic uncertainties are the major factors undermining the advantages of proton therapy, namely, a sharp dose falloff and a better dose conformality for lower doses in normal tissues. The influence of CT artifacts such as beam hardening or scatter can easily be understood and estimated due to their large-scale effects on the CT image, like cupping and streaks. In comparison, the effects of weakly-correlated stochastic noise are more insidious and less attention is drawn on them partly due to the common belief that they only contribute to proton range uncertainties and not to systematic errors thanks to some averaging effects. A new source of systematic errors on the range and relative stopping powers (RSP) has been highlighted and proved not to be negligible compared to the 3.5% uncertainty reference value used for safety margin design. Hence, we demonstrate that the angular points in the HU-to-RSP calibration curve are an intrinsic source of proton range systematic error for typical levels of zero-mean stochastic CT noise. Systematic errors on RSP of up to 1% have been computed for these levels. We also show that the range uncertainty does not generally vary linearly with the noise standard deviation. We define a noise-dependent effective calibration curve that better describes, for a given material, the RSP value that is actually used. The statistics of the RSP and the range continuous slowing down approximation (CSDA) have been analytically derived for the general case of a calibration curve obtained by the stoichiometric calibration procedure. These models have been validated against actual CSDA simulations for homogeneous and heterogeneous synthetical objects as well as on actual patient CTs for prostate and head-and-neck treatment planning situations.

  12. Cooperation of deterministic dynamics and random noise in production of complex syntactical avian song sequences: a neural network model

    Directory of Open Access Journals (Sweden)

    Yuichi eYamashita

    2011-04-01

    Full Text Available How the brain learns and generates temporal sequences is a fundamental issue in neuroscience. The production of birdsongs, a process which involves complex learned sequences, provides researchers with an excellent biological model for this topic. The Bengalese finch in particular learns a highly complex song with syntactical structure. The nucleus HVC (HVC, a premotor nucleus within the avian song system, plays a key role in generating the temporal structures of their songs. From lesion studies, the nucleus interfacialis (NIf projecting to the HVC is considered one of the essential regions that contribute to the complexity of their songs. However, the types of interaction between the HVC and the NIf that can produce complex syntactical songs remain unclear. In order to investigate the function of interactions between the HVC and NIf, we have proposed a neural network model based on previous biological evidence. The HVC is modeled by a recurrent neural network (RNN that learns to generate temporal patterns of songs. The NIf is modeled as a mechanism that provides auditory feedback to the HVC and generates random noise that feeds into the HVC. The model showed that complex syntactical songs can be replicated by simple interactions between deterministic dynamics of the RNN and random noise. In the current study, the plausibility of the model is tested by the comparison between the changes in the songs of actual birds induced by pharmacological inhibition of the NIf and the changes in the songs produced by the model resulting from modification of parameters representing NIf functions. The efficacy of the model demonstrates that the changes of songs induced by pharmacological inhibition of the NIf can be interpreted as a trade-off between the effects of noise and the effects of feedback on the dynamics of the RNN of the HVC. These facts suggest that the current model provides a convincing hypothesis for the functional role of NIf-HVC interaction.

  13. Training in using earplugs or using earplugs with a higher than necessary noise reduction rating? A randomized clinical trial.

    Science.gov (United States)

    Salmani Nodoushan, M; Mehrparvar, A H; Torab Jahromi, M; Safaei, S; Mollasadeghi, A

    2014-10-01

    Noise-induced hearing loss (NIHL) is one of the most common occupational diseases and the second most common cause of workers' claims for occupational injuries. Due to high prevalence of NIHL and several reports of improper use of hearing protective devices (HPDs), we conducted this study to compare the effect of face-to-face training in effective use of earplugs with appropriate NRR to overprotection of workers by using earplugs with higher than necessary noise reduction rating (NRR). In a randomized clinical trial, 150 workers referred to occupational medicine clinic were randomly allocated to three arms---a group wearing earplugs with an NRR of 25 with no training in appropriate use of the device; a group wearing earplugs with an NRR of 25 with training; another group wearing earplugs with an NRR of 30, with no training. Hearing threshold was measured in the study groups by real ear attenuation at threshold (REAT) method. This trial is registered with Australian New Zealand clinical trials Registry, number ACTRN00363175. The mean ± SD age of the participants was 28 ± 5 (range: 19-39) years. 42% of participants were female. The mean noise attenuation in the group with training was 13.88 dB, significantly higher than those observed in other groups. The highest attenuation was observed in high frequencies (4, 6, and 8 kHz) in the group with training. Training in appropriate use of earplugs significantly affects the efficacy of earplugs---even more than using an earplug with higher NRR.

  14. Training in Using Earplugs or Using Earplugs with a Higher than Necessary Noise Reduction Rating? A Randomized Clinical Trial

    Directory of Open Access Journals (Sweden)

    M Salmani Nodoushan

    2014-09-01

    Full Text Available Background: Noise-induced hearing loss (NIHL is one of the most common occupational diseases and the second most common cause of workers' claims for occupational injuries. Objective: Due to high prevalence of NIHL and several reports of improper use of hearing protective devices (HPDs, we conducted this study to compare the effect of face-to-face training in effective use of earplugs with appropriate NRR to overprotection of workers by using earplugs with higher than necessary noise reduction rating (NRR. Methods: In a randomized clinical trial, 150 workers referred to occupational medicine clinic were randomly allocated to three arms—a group wearing earplugs with an NRR of 25 with no training in appropriate use of the device; a group wearing earplugs with an NRR of 25 with training; another group wearing earplugs with an NRR of 30, with no training. Hearing threshold was measured in the study groups by real ear attenuation at threshold (REAT method. This trial is registered with Australian New Zealand clinical trials Registry, number ACTRN00363175. Results: The mean±SD age of the participants was 28±5 (range: 19–39 years. 42% of participants were female. The mean noise attenuation in the group with training was 13.88 dB, significantly higher than those observed in other groups. The highest attenuation was observed in high frequencies (4, 6, and 8 kHz in the group with training. Conclusion: Training in appropriate use of earplugs significantly affects the efficacy of earplugs—even more than using an earplug with higher NRR.

  15. Neuropathic pain: transcranial electric motor cortex stimulation using high frequency random noise. Case report of a novel treatment

    Directory of Open Access Journals (Sweden)

    Alm PA

    2013-06-01

    Full Text Available Per A Alm, Karolina DreimanisDepartment of Neuroscience, Uppsala University, Uppsala, SwedenObjectives: Electric motor cortex stimulation has been reported to be effective for many cases of neuropathic pain, in the form of epidural stimulation or transcranial direct current stimulation (tDCS. A novel technique is transcranial random noise stimulation (tRNS, which increases the cortical excitability irrespective of the orientation of the current. The aim of this study was to investigate the effect of tRNS on neuropathic pain in a small number of subjects, and in a case study explore the effects of different stimulation parameters and the long-term stability of treatment effects.Methods: The study was divided into three phases: (1 a double-blind 100–600 Hz, varying from 0.5 to 10 minutes and from 50 to 1500 µA, at intervals ranging from daily to fortnightly.crossover study, with four subjects; (2 a double-blind extended case study with one responder; and (3 open continued treatment. The motor cortex stimulation consisted of alternating current random noise (100–600 Hz, varying from 0.5 to 10 minutes and from 50 to 1500 μA, at intervals ranging from daily to fortnightly.Results: One out of four participants showed a strong positive effect (also compared with direct-current-sham, P = 0.006. Unexpectedly, this effect was shown to occur also for very weak (100 µA, P = 0.048 and brief (0.5 minutes, P = 0.028 stimulation. The effect was largest during the first month, but remained at a highly motivating level for the patient after 6 months.Discussion: The study suggests that tRNS may be an effective treatment for some cases of neuropathic pain. An important result was the indication that even low levels of stimulation may have substantial effects.Keywords: neuropathic pain, central pain, transcranial direct current stimulation, motor cortex stimulation, random noise stimulation

  16. Communicating the Signal of Climate Change in The Presence of Non-Random Noise

    Science.gov (United States)

    Mann, M. E.

    2015-12-01

    The late Stephen Schneider spoke eloquently of the double ethical bind that we face: we must strive to communicate effectively but honestly. This is no simple task given the considerable "noise" generated in our public discourse by vested interests instead working to misinform the public. To do so, we must convey what is known in plainspoken jargon-free language, while acknowledging the real uncertainties that exist. Further, we must explain the implications of those uncertainties, which in many cases imply the possibility of greater, not lesser, risk. Finally, we must not be averse to discussing the policy implications of the science, lest we fail to provide our audience with critical information that can help them make informed choices about their own actions as citizens. I will use examples from my current collaboration with Washington Post editorial cartoonist Tom Toles.

  17. E-learning and deliberate practice for oral case presentation skills: a randomized trial.

    Science.gov (United States)

    Heiman, Heather L; Uchida, Toshiko; Adams, Craig; Butter, John; Cohen, Elaine; Persell, Stephen D; Pribaz, Paul; McGaghie, William C; Martin, Gary J

    2012-01-01

    Oral case presentations are critical for patient care and student assessment. The best method to prepare early medical students for oral presentations is unknown. We aimed to develop and evaluate a curriculum of on-line learning and deliberate practice to improve pre-clinical students' case presentation skills. We developed a web-based, interactive curriculum emphasizing conciseness and clinical reasoning. Using a waitlist control design, we randomly assigned groups of second-year students to receive the curriculum in December 2010 or in April 2011. We evaluated their presentations at three time points. We also examined the performance of an untrained class of students as a historical comparison. We evaluated 132 second-year medical students at three time points. After the curriculum, mean scores of the intervention students improved from 60.2% to 70.1%, while scores of the waitlist control students improved less, from 61.8% to 64.5% (p oral presentation skills.

  18. Conservation laws in coupled multiplicative random arrays lead to $1/f$ noise

    CERN Document Server

    Thurner, S; Teich, M C; Thurner, Stefan; Feurstein, Markus C.; Teich, Malvin C.

    1997-01-01

    We consider the dynamic evolution of a coupled array of N multiplicative random variables. The magnitude of each is constrained by a lower bound w_0 and their sum is conserved. Analytical calculation shows that the simplest case, N=2 and w_0=0, exhibits a Lorentzian spectrum which gradually becomes fractal as w_0 increases. Simulation results for larger $N$ reveal fractal spectra for moderate to high values of w_0 and power-law amplitude fluctuations at all values. The results are applied to estimating the fractal exponents for cochlear-nerve-fiber action-potential sequences with remarkable success, using only two parameters.

  19. Versatile quantitative phase imaging system applied to high-speed, low noise and multimodal imaging (Conference Presentation)

    Science.gov (United States)

    Federici, Antoine; Aknoun, Sherazade; Savatier, Julien; Wattellier, Benoit F.

    2017-02-01

    Quadriwave lateral shearing interferometry (QWLSI) is a well-established quantitative phase imaging (QPI) technique based on the analysis of interference patterns of four diffraction orders by an optical grating set in front of an array detector [1]. As a QPI modality, this is a non-invasive imaging technique which allow to measure the optical path difference (OPD) of semi-transparent samples. We present a system enabling QWLSI with high-performance sCMOS cameras [2] and apply it to perform high-speed imaging, low noise as well as multimodal imaging. This modified QWLSI system contains a versatile optomechanical device which images the optical grating near the detector plane. Such a device is coupled with any kind of camera by varying its magnification. In this paper, we study the use of a sCMOS Zyla5.5 camera from Andor along with our modified QWLSI system. We will present high-speed live cell imaging, up to 200Hz frame rate, in order to follow intracellular fast motions while measuring the quantitative phase information. The structural and density information extracted from the OPD signal is complementary to the specific and localized fluorescence signal [2]. In addition, QPI detects cells even when the fluorophore is not expressed. This is very useful to follow a protein expression with time. The 10 µm spatial pixel resolution of our modified QWLSI associated to the high sensitivity of the Zyla5.5 enabling to perform high quality fluorescence imaging, we have carried out multimodal imaging revealing fine structures cells, like actin filaments, merged with the morphological information of the phase. References [1]. P. Bon, G. Maucort, B. Wattellier, and S. Monneret, "Quadriwave lateral shearing interferometry for quantitative phase microscopy of living cells," Opt. Express, vol. 17, pp. 13080-13094, 2009. [2] P. Bon, S. Lécart, E. Fort and S. Lévêque-Fort, "Fast label-free cytoskeletal network imaging in living mammalian cells," Biophysical journal, 106

  20. Number of traps and trap depth position on statistical distribution of random telegraph noise in scaled NAND flash memory

    Science.gov (United States)

    Tomita, Toshihiro; Miyaji, Kousuke

    2016-04-01

    The dependence of random telegraph noise (RTN) amplitude distribution on the number of traps and trap depth position is investigated using three-dimensional Monte Carlo device simulation including random dopant fluctuation (RDF) in a 30 nm NAND multi level flash memory. The ΔV th tail distribution becomes broad at fixed double traps, indicating that the number of traps greatly affects the worst RTN characteristics. It is also found that for both fixed single and fixed double traps, the ΔV th distribution in the lowest cell threshold voltage (V th) state shows the broadest distribution among all cell V th states. This is because the drain current flows at the channel surface in the lowest cell V th state, while at a high cell V th, it flows at the deeper position owing to the fringing coupling between the control gate (CG) and the channel. In this work, the ΔV th distribution with the number of traps following the Poisson distribution is also considered to cope with the variations in trap number. As a result, it is found that the number of traps is an important factor for understanding RTN characteristics. In addition, considering trap position in the tunnel oxide thickness direction is also an important factor.

  1. Statistical Analysis of the Random Telegraph Noise in a 1.1 μm Pixel, 8.3 MP CMOS Image Sensor Using On-Chip Time Constant Extraction Method.

    Science.gov (United States)

    Chao, Calvin Yi-Ping; Tu, Honyih; Wu, Thomas Meng-Hsiu; Chou, Kuo-Yu; Yeh, Shang-Fu; Yin, Chin; Lee, Chih-Lin

    2017-11-23

    A study of the random telegraph noise (RTN) of a 1.1 μm pitch, 8.3 Mpixel CMOS image sensor (CIS) fabricated in a 45 nm backside-illumination (BSI) technology is presented in this paper. A noise decomposition scheme is used to pinpoint the noise source. The long tail of the random noise (RN) distribution is directly linked to the RTN from the pixel source follower (SF). The full 8.3 Mpixels are classified into four categories according to the observed RTN histogram peaks. A theoretical formula describing the RTN as a function of the time difference between the two phases of the correlated double sampling (CDS) is derived and validated by measured data. An on-chip time constant extraction method is developed and applied to the RTN analysis. The effects of readout circuit bandwidth on the settling ratios of the RTN histograms are investigated and successfully accounted for in a simulation using a RTN behavior model.

  2. An efficient ERP-based brain-computer interface using random set presentation and face familiarity.

    Directory of Open Access Journals (Sweden)

    Seul-Ki Yeom

    Full Text Available Event-related potential (ERP-based P300 spellers are commonly used in the field of brain-computer interfaces as an alternative channel of communication for people with severe neuro-muscular diseases. This study introduces a novel P300 based brain-computer interface (BCI stimulus paradigm using a random set presentation pattern and exploiting the effects of face familiarity. The effect of face familiarity is widely studied in the cognitive neurosciences and has recently been addressed for the purpose of BCI. In this study we compare P300-based BCI performances of a conventional row-column (RC-based paradigm with our approach that combines a random set presentation paradigm with (non- self-face stimuli. Our experimental results indicate stronger deflections of the ERPs in response to face stimuli, which are further enhanced when using the self-face images, and thereby improving P300-based spelling performance. This lead to a significant reduction of stimulus sequences required for correct character classification. These findings demonstrate a promising new approach for improving the speed and thus fluency of BCI-enhanced communication with the widely used P300-based BCI setup.

  3. Presentation and verification of a simple mathematical model foridentification of the areas behind noise barrierwith the highest performance

    Directory of Open Access Journals (Sweden)

    M. Monazzam

    2009-07-01

    Full Text Available Background and aims   Traffic noise barriers are the most important measure to control the environmental noise pollution. Diffraction from top edge of noise barriers is the most important path of indirect sound wave moves towards receiver.Therefore, most studies are focused on  improvement of this kind.   Methods   T-shape profile barriers are one of the most successful barrier among many different profiles. In this investigation the theory of destructive effect of diffracted waves from real edge of barrier and the wave diffracted from image of the barrier with phase difference of radians is used. Firstly a simple mathematical representation of the zones behind rigid and absorbent T- shape barriers with the highest insertion loss using the destructive effect of indirect path via barrier  image is introduced and then two different profile reflective and absorption barrier is used for  verification of the introduced model   Results   The results are then compared with the results of a verified two dimensional boundary element method at 1/3 octave band frequencies and in a wide field behind those barriers. Avery good agreement between the results has been achieved. In this method effective height is used for any different profile barriers.   Conclusion   The introduced model is very simple, flexible and fast and could be used for choosing the best location of profile rigid and absorptive barriers to achieve the highest  performance.  

  4. Random genetic drift, natural selection, and noise in human cranial evolution.

    Science.gov (United States)

    Roseman, Charles C

    2016-08-01

    This study assesses the extent to which relationships among groups complicate comparative studies of adaptation in recent human cranial variation and the extent to which departures from neutral additive models of evolution hinder the reconstruction of population relationships among groups using cranial morphology. Using a maximum likelihood evolutionary model fitting approach and a mixed population genomic and cranial data set, I evaluate the relative fits of several widely used models of human cranial evolution. Moreover, I compare the goodness of fit of models of cranial evolution constrained by genomic variation to test hypotheses about population specific departures from neutrality. Models from population genomics are much better fits to cranial variation than are traditional models from comparative human biology. There is not enough evolutionary information in the cranium to reconstruct much of recent human evolution but the influence of population history on cranial variation is strong enough to cause comparative studies of adaptation serious difficulties. Deviations from a model of random genetic drift along a tree-like population history show the importance of environmental effects, gene flow, and/or natural selection on human cranial variation. Moreover, there is a strong signal of the effect of natural selection or an environmental factor on a group of humans from Siberia. The evolution of the human cranium is complex and no one evolutionary process has prevailed at the expense of all others. A holistic unification of phenome, genome, and environmental context, gives us a strong point of purchase on these problems, which is unavailable to any one traditional approach alone. Am J Phys Anthropol 160:582-592, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  5. Presentation

    Directory of Open Access Journals (Sweden)

    Eduardo Vicente

    2013-06-01

    Full Text Available In the present edition of Significação – Scientific Journal for Audiovisual Culture and in the others to follow something new is brought: the presence of thematic dossiers which are to be organized by invited scholars. The appointed subject for the very first one of them was Radio and the invited scholar, Eduardo Vicente, professor at the Graduate Course in Audiovisual and at the Postgraduate Program in Audiovisual Media and Processes of the School of Communication and Arts of the University of São Paulo (ECA-USP. Entitled Radio Beyond Borders the dossier gathers six articles and the intention of reuniting works on the perspectives of usage of such media as much as on the new possibilities of aesthetical experimenting being build up for it, especially considering the new digital technologies and technological convergences. It also intends to present works with original theoretical approach and original reflections able to reset the way we look at what is today already a centennial media. Having broadened the meaning of “beyond borders”, four foreign authors were invited to join the dossier. This is the first time they are being published in this country and so, in all cases, the articles where either written or translated into Portuguese.The dossier begins with “Radio is dead…Long live to the sound”, which is the transcription of a thought provoking lecture given by Armand Balsebre (Autonomous University of Barcelona – one of the most influential authors in the world on the Radio study field. It addresses the challenges such media is to face so that it can become “a new sound media, in the context of a new soundscape or sound-sphere, for the new listeners”. Andrew Dubber (Birmingham City University regarding the challenges posed by a Digital Era argues for a theoretical approach in radio studies which can consider a Media Ecology. The author understands the form and discourse of radio as a negotiation of affordances and

  6. Robust random telegraph conductivity noise in single crystals of the ferromagnetic insulating manganite La0.86Ca0.14MnO3

    Science.gov (United States)

    Przybytek, J.; Fink-Finowicki, J.; Puźniak, R.; Shames, A.; Markovich, V.; Mogilyansky, D.; Jung, G.

    2017-03-01

    Robust random telegraph conductivity fluctuations have been observed in La0.86Ca0.14MnO3 manganite single crystals. At room temperatures, the spectra of conductivity fluctuations are featureless and follow a 1 /f shape in the entire experimental frequency and bias range. Upon lowering the temperature, clear Lorentzian bias-dependent excess noise appears on the 1 /f background and eventually dominates the spectral behavior. In the time domain, fully developed Lorentzian noise appears as pronounced two-level random telegraph noise with a thermally activated switching rate, which does not depend on bias current and applied magnetic field. The telegraph noise is very robust and persists in the exceptionally wide temperature range of more than 50 K. The amplitude of the telegraph noise decreases exponentially with increasing bias current in exactly the same manner as the sample resistance increases with the current, pointing out the dynamic current redistribution between percolation paths dominated by phase-separated clusters with different conductivity as a possible origin of two-level conductivity fluctuations.

  7. Target noise in overlay metrology

    Science.gov (United States)

    Seligson, Joel L.; Adel, Mike E.; Izikson, Pavel; Levinski, Vladimir; Yaffe, Dan

    2004-05-01

    We have developed a method for calculating the statistical effects of spatial noise on the overlay measurement extracted from a given overlay target. The method has been applied to two kinds of overlay targets on three process layers, and the new metric, Target Noise, has been shown to correlate well to the random component of Overlay Mark Fidelity. A significant difference in terms of robustness has been observed between AIM targets and conventional Frame-in-Frame targets. The results fit well into the spatial noise hierarchy presented in this paper.

  8. Analysis of magnetic random telegraph noise in individual arrangements of a small number of coupled MnAs nanoclusters

    Science.gov (United States)

    Fischer, Martin; Elm, Matthias T.; Kato, Hiroaki; Sakita, Shinya; Hara, Shinjiro; Klar, Peter J.

    2015-10-01

    The temporal dependence of the resistance of MnAs nanocluster arrangements grown by selective-area metal-organic vapor-phase epitaxy is investigated at different temperatures. The resistance of such arrangements exhibits random telegraph noise with jumps between discrete resistance levels. The effect is attributed to thermally activated switching of the magnetic domain structure resulting in alterations of spin-dependent scattering between the MnAs clusters of the arrangements. The behavior can be qualitatively understood by a simple model in which it is assumed that the nanocluster arrangement consists of three domains in accordance with investigations by magnetic force microscopy. The magnetizations of the outer larger domains remain fixed, whereas the magnetization of a smaller intermediate domain (or domain wall) exhibits thermally activated switching between local minima of its energy landscape. The results of the model indicate that the time scale of an actual switching event of the entire intermediate domain comprises the nucleation of a seed domain consisting of a few thousand Mn spins followed by the transformation of the entire domain by domain-wall motion in order to reorient its magnetization.

  9. Transcranial random noise stimulation and cognitive training to improve learning and cognition of the atypically developing brain: A pilot study.

    Science.gov (United States)

    Looi, Chung Yen; Lim, Jenny; Sella, Francesco; Lolliot, Simon; Duta, Mihaela; Avramenko, Alexander Alexandrovich; Cohen Kadosh, Roi

    2017-07-05

    Learning disabilities that affect about 10% of human population are linked to atypical neurodevelopment, but predominantly treated by behavioural interventions. Behavioural interventions alone have shown little efficacy, indicating limited success in modulating neuroplasticity, especially in brains with neural atypicalities. Even in healthy adults, weeks of cognitive training alone led to inconsistent generalisable training gains, or "transfer effects" to non-trained materials. Meanwhile, transcranial random noise stimulation (tRNS), a painless and more direct neuromodulation method was shown to further promote cognitive training and transfer effects in healthy adults without harmful effects. It is unknown whether tRNS on the atypically developing brain might promote greater learning and transfer outcomes than training alone. Here, we show that tRNS over the bilateral dorsolateral prefrontal cortices (dlPFCs) improved learning and performance of children with mathematical learning disabilities (MLD) during arithmetic training compared to those who received sham (placebo) tRNS. Training gains correlated positively with improvement on a standardized mathematical diagnostic test, and this effect was strengthened by tRNS. These findings mirror those in healthy adults, and encourage replications using larger cohorts. Overall, this study offers insights into the concept of combining tRNS and cognitive training for improving learning and cognition of children with learning disabilities.

  10. The application of online transcranial random noise stimulation and perceptual learning in the improvement of visual functions in mild myopia.

    Science.gov (United States)

    Camilleri, Rebecca; Pavan, Andrea; Campana, Gianluca

    2016-08-01

    It has recently been demonstrated how perceptual learning, that is an improvement in a sensory/perceptual task upon practice, can be boosted by concurrent high-frequency transcranial random noise stimulation (tRNS). It has also been shown that perceptual learning can generalize and produce an improvement of visual functions in participants with mild refractive defects. By using three different groups of participants (single-blind study), we tested the efficacy of a short training (8 sessions) using a single Gabor contrast-detection task with concurrent hf-tRNS in comparison with the same training with sham stimulation or hf-tRNS with no concurrent training, in improving visual acuity (VA) and contrast sensitivity (CS) of individuals with uncorrected mild myopia. A short training with a contrast detection task is able to improve VA and CS only if coupled with hf-tRNS, whereas no effect on VA and marginal effects on CS are seen with the sole administration of hf-tRNS. Our results support the idea that, by boosting the rate of perceptual learning via the modulation of neuronal plasticity, hf-tRNS can be successfully used to reduce the duration of the perceptual training and/or to increase its efficacy in producing perceptual learning and generalization to improved VA and CS in individuals with uncorrected mild myopia. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. A randomized trial of remifentanil for analgesia in external cephalic version for breech presentation.

    Science.gov (United States)

    Liu, Xiaohua; Xue, Aiqin

    2016-12-01

    Although external cephalic version (ECV) can be effective for correcting the fetus in a cephalic presentation, it may be painful for the mother. This study aimed to evaluate the efficacy and safety of remifentanil for pain relief during ECV in China. In all, 152 Chinese parturients with singleton breech presentation were randomly divided into 2 groups, each with 76 patients. All 152 patients were assigned to receive either remifentanil (infused at 0.1 μg/kg/min and demand boluses of 0.1 μg/kg) or saline placebo. The study was performed between January 2012 and December 2015. Outcome measurements included the Numerical Rating Pain Scale score (0-10) after ECV, success rate for ECV, and maternal satisfaction after ECV. Adverse events were also evaluated. The study was completed by 146 patients. Remifentanil showed greater efficacy than placebo in decreasing the pain score immediately after ECV (remifentanil 4.6 ± 2.6 vs placebo 6.5 ± 2.7; P ECV showed a significant difference between the 2 groups (remifentanil 56.5% vs placebo 39.5%; P = 0.04). Maternal satisfaction also showed a significant difference between the 2 groups (remifentanil 9.6 ± 1.4 vs placebo 6.4 ± 3.7; P ECV, and increasing maternal satisfaction during ECV, and is generally well-tolerated without additional adverse effects.

  12. Influence of correspondence noise and spatial scaling on the upper limit for spatial displacement in fully-coherent random-dot kinematogram stimuli.

    Directory of Open Access Journals (Sweden)

    Srimant P Tripathy

    Full Text Available Correspondence noise is a major factor limiting direction discrimination performance in random-dot kinematograms. In the current study we investigated the influence of correspondence noise on Dmax, which is the upper limit for the spatial displacement of the dots for which coherent motion is still perceived. Human direction discrimination performance was measured, using 2-frame kinematograms having leftward/rightward motion, over a 200-fold range of dot-densities and a four-fold range of dot displacements. From this data Dmax was estimated for the different dot densities tested. A model was proposed to evaluate the correspondence noise in the stimulus. This model summed the outputs of a set of elementary Reichardt-type local detectors that had receptive fields tiling the stimulus and were tuned to the two directions of motion in the stimulus. A key assumption of the model was that the local detectors would have the radius of their catchment areas scaled with the displacement that they were tuned to detect; the scaling factor k linking the radius to the displacement was the only free parameter in the model and a single value of k was used to fit all of the psychophysical data collected. This minimal, correspondence-noise based model was able to account for 91% of the variability in the human performance across all of the conditions tested. The results highlight the importance of correspondence noise in constraining the largest displacement that can be detected.

  13. Occupational noise management

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-06-15

    Occupational noise is a frequently encountered on-the-job health hazard. This guide presented the responsibilities and regulatory requirements related to business activities where noise above 80 decibels is present. The guide provided a definition of noise and discussed noise hazards, types of noise, and on-the-job noise exposure. A risk assessment to noise in the work environment was also discussed. A guide to a hearing conservation program was also included. The main purpose of a hearing conservation program is the prevention of noise induced hearing loss for employees exposed to occupational noise. The components of such a program were outlined, with particular reference to noise monitoring; noise exposure control; worker education and training; hearing (audiometric) testing; and annual program review and record keeping. It was concluded that in terms of record keeping, it can be very helpful to file noise exposure assessments, particularly personal exposure measurements, with hearing test records to facilitate for future reference. refs., appendices.

  14. Noise suppression by noise

    OpenAIRE

    Vilar, J. M. G.; Rubí Capaceti, José Miguel

    2001-01-01

    We have analyzed the interplay between an externally added noise and the intrinsic noise of systems that relax fast towards a stationary state, and found that increasing the intensity of the external noise can reduce the total noise of the system. We have established a general criterion for the appearance of this phenomenon and discussed two examples in detail.

  15. Active noise control in a duct to cancel broadband noise

    Science.gov (United States)

    Chen, Kuan-Chun; Chang, Cheng-Yuan; Kuo, Sen M.

    2017-09-01

    The paper presents cancelling duct noises by using the active noise control (ANC) techniques. We use the single channel feed forward algorithm with feedback neutralization to realize ANC. Several kinds of ducts noises including tonal noises, sweep tonal signals, and white noise had investigated. Experimental results show that the proposed ANC system can cancel these noises in a PVC duct very well. The noise reduction of white noise can be up to 20 dB.

  16. Transcranial Random Noise Stimulation Does Not Improve Behavioral and Neurophysiological Measures in Patients with Subacute Vegetative-Unresponsive Wakefulness State (VS-UWS

    Directory of Open Access Journals (Sweden)

    Mauro Mancuso

    2017-11-01

    Full Text Available Background: The absence of efficient treatments capable to promote central nervous system recovery in patients in vegetative state (VS due to a severe acquired brain injury highlights the need of exploring alternative neuromodulatory treatments that can lead to neurobehavioral gains. Some encouraging preliminary observations suggest that transcranial direct current stimulation could be effective in disorders of consciousness (DoC patients, especially when applied on the dorsolateral prefrontal cortex (DLPFC in patients with minimally conscious state (MCS but not in those with VS.Objective: The primary aim of the present study was to verify if the application of transcranial random noise stimulation (tRNS on the DLPFC might favor improvements of consciousness recovery in subacute VS-UWS.Methods: Nine patients with DoC due to traumatic brain injury (n = 1, anoxia (n = 3, and vascular damage (n = 5, have undergone a randomized, double-blind, sham-controlled, neuromodulatory trial with tRNS of bilateral DLPFC. All patients were in a post-acute phase and the DoC onset ranged from 30 days to 4 months. The diagnosis of DoC was based on internationally established criteria from the Multi-Society Task Force on PVS, and classified as VS or MCS using the JFK Coma Recovery Scale-Revised scores (CRS-R. We used CRS-R, Synek Scale, Ad-Hoc semi-quantitative scale and the Clinical Global Impression-Improvement scale to measure behavioral and electrophysiological changes during tRNS intervention. All patients were also treated with daily conventional rehabilitation treatment.Results: No significant differences emerged between active and sham groups regarding improvements of level of consciousness, as well as on electroencephalographic data. Only one patient showed emergence from VS-UWS, evolving from VS to MCS after the tRNS stimulation, at a distance of 3 weeks from the enrolment into the study.Conclusion: Repeated applications of tRNS of the DLPFC, even if

  17. Narrowband (LPC-10) Vocoder Performance under Combined Effects of Random Bit Errors and Jet Aircraft Cabin Noise.

    Science.gov (United States)

    1983-12-01

    Environment 52 34. Comparison of Regression Lines Estimating Scores for the Sustention Intelligibility Feature vs Bit Error Rate for the DOD LPC-10 Vocoder in...both conditions, the feature "sibilation" obtained the highest scores, and the features "graveness" and " sustention " received the poorest scores, but...were under much greater impairment in the noise environment. Details of the variations in scores for sustention are shown in Figure 34, and, for

  18. Noise and Health: How does noise affect us?

    NARCIS (Netherlands)

    Miedema, H.M.E.

    2001-01-01

    Noise annoyance is a primary indication that noise is a problem, and by itself noise annoyance means that the quality of life is adversely affected. Results from noise annoyance research are presented that make possible a detailed evaluation of noise exposures with respect to the annoyance induced.

  19. Drone noise

    Science.gov (United States)

    Tinney, Charles; Sirohi, Jayant; University of Texas at Austin Team

    2017-11-01

    A basic understanding of the noise produced by single and multirotor drones operating at static thrust conditions is presented. This work acts as an extension to previous efforts conducted at The University of Texas at Austin (Tinney et al. 2017, AHS Forum 73). Propeller diameters ranging from 8 inch to 12 inch are examined for configurations comprising an isolated rotor, a quadcopter configuration and a hexacopter configuration, and with a constant drone pitch of 2.25. An azimuthal array of half-inch microphones, placed between 2 and 3 hub-center diameters from the drone center, are used to assess the acoustic near-field. Thrust levels, acquired using a six degree-of-freedom load cell, are then used to correlate acoustic noise levels to aerodynamic performance for each drone configuration. The findings reveal a nearly logarithmic increase in noise with increasing thrust. However, for the same thrust condition, considerable noise reduction is achieved by increasing the number of propeller blades thereby reducing the blade passage frequency and both the thickness and loading noise sources that accompany it.

  20. Introduction to noise-resilient computing

    CERN Document Server

    Yanushkevich, Svetlana N; Tangim, Golam

    2013-01-01

    Noise abatement is the key problem of small-scaled circuit design. New computational paradigms are needed -- as these circuits shrink, they become very vulnerable to noise and soft errors. In this lecture, we present a probabilistic computation framework for improving the resiliency of logic gates and circuits under random conditions induced by voltage or current fluctuation. Among many probabilistic techniques for modeling such devices, only a few models satisfy the requirements of efficient hardware implementation -- specifically, Boltzman machines and Markov Random Field (MRF) models. These

  1. Solar noise storms

    CERN Document Server

    Elgaroy, E O

    2013-01-01

    Solar Noise Storms examines the properties and features of solar noise storm phenomenon. The book also presents some theories that can be used to gain a better understanding of the phenomenon. The coverage of the text includes topics that cover the features and behavior of noise storms, such as the observable features of noise storms; the relationship between noise storms and the observable features on the sun; and ordered behavior of storm bursts in the time-frequency plane. The book also covers the spectrum, polarization, and directivity of noise storms. The text will be of great use to astr

  2. The Spread of a Noise Field in a Dispersive Medium

    Directory of Open Access Journals (Sweden)

    Cohen Leon

    2010-01-01

    Full Text Available We discuss the production of induced noise by a pulse and the propagation of the noise in a dispersive medium. We present a simple model where the noise is the sum of pulses and where the mean of each pulse is random. We obtain explicit expressions for the standard deviation of the spatial noise as a function of time. We also formulate the problem in terms of a time-frequency phase space approach and in particular we use the Wigner distribution to define the spatial/spatial-frequency distribution.

  3. Robust thresholdlike effect of internal noise on stochastic resonance in an organic field-effect transistor

    Science.gov (United States)

    Suzuki, Yoshiharu; Asakawa, Naoki

    2018-01-01

    The application of noise to a nonlinear system can have the effect of increasing the signal transmission of the system through the phenomenon of stochastic resonance (SR). This paper presents an analytical characterization of the dependence of the signal transmission performance of an organic field-effect transistor (OFET) on external noise. Similarly to the threshold of a nonlinear system, the additive internal noise of the system can be used to control the emergence of SR. Internal noise or the addition of random numbers to the system enables one to observe the SR phenomenon in an OFET under an intrinsically nonresonant condition. Internal noise plays a thresholdlike role, but it functions in a different manner. The fluctuations in performance due to external noise become smaller when the effect of internal noise becomes dominant compared with that of the threshold. In conclusion, it is found that internal noise plays a robust thresholdlike role with respect to variations in external noise intensity.

  4. The Signal Importance of Noise

    Science.gov (United States)

    Macy, Michael; Tsvetkova, Milena

    2015-01-01

    Noise is widely regarded as a residual category--the unexplained variance in a linear model or the random disturbance of a predictable pattern. Accordingly, formal models often impose the simplifying assumption that the world is noise-free and social dynamics are deterministic. Where noise is assigned causal importance, it is often assumed to be a…

  5. Effects of background noise on total noise annoyance

    Science.gov (United States)

    Willshire, K. F.

    1987-01-01

    Two experiments were conducted to assess the effects of combined community noise sources on annoyance. The first experiment baseline relationships between annoyance and noise level for three community noise sources (jet aircraft flyovers, traffic and air conditioners) presented individually. Forty eight subjects evaluated the annoyance of each noise source presented at four different noise levels. Results indicated the slope of the linear relationship between annoyance and noise level for the traffic noise was significantly different from that of aircraft and of air conditioner noise, which had equal slopes. The second experiment investigated annoyance response to combined noise sources, with aircraft noise defined as the major noise source and traffic and air conditioner noise as background noise sources. Effects on annoyance of noise level differences between aircraft and background noise for three total noise levels and for both background noise sources were determined. A total of 216 subjects were required to make either total or source specific annoyance judgements, or a combination of the two, for a wide range of combined noise conditions.

  6. Noise estimation for remote sensing image data analysis

    Science.gov (United States)

    Du, Qian

    2004-01-01

    Noise estimation does not receive much attention in remote sensing society. It may be because normally noise is not large enough to impair image analysis result. Noise estimation is also very challenging due to the randomness nature of the noise (for random noise) and the difficulty of separating the noise component from the signal in each specific location. We review and propose seven different types of methods to estimate noise variance and noise covariance matrix in a remotely sensed image. In the experiment, it is demonstrated that a good noise estimate can improve the performance of an algorithm via noise whitening if this algorithm assumes white noise.

  7. Adaptation to random and systematic errors: Comparison of amputee and non-amputee control interfaces with varying levels of process noise.

    Directory of Open Access Journals (Sweden)

    Reva E Johnson

    Full Text Available The objective of this study was to understand how people adapt to errors when using a myoelectric control interface. We compared adaptation across 1 non-amputee subjects using joint angle, joint torque, and myoelectric control interfaces, and 2 amputee subjects using myoelectric control interfaces with residual and intact limbs (five total control interface conditions. We measured trial-by-trial adaptation to self-generated errors and random perturbations during a virtual, single degree-of-freedom task with two levels of feedback uncertainty, and evaluated adaptation by fitting a hierarchical Kalman filter model. We have two main results. First, adaptation to random perturbations was similar across all control interfaces, whereas adaptation to self-generated errors differed. These patterns matched predictions of our model, which was fit to each control interface by changing the process noise parameter that represented system variability. Second, in amputee subjects, we found similar adaptation rates and error levels between residual and intact limbs. These results link prosthesis control to broader areas of motor learning and adaptation and provide a useful model of adaptation with myoelectric control. The model of adaptation will help us understand and solve prosthesis control challenges, such as providing additional sensory feedback.

  8. Adaptation to random and systematic errors: Comparison of amputee and non-amputee control interfaces with varying levels of process noise.

    Science.gov (United States)

    Johnson, Reva E; Kording, Konrad P; Hargrove, Levi J; Sensinger, Jonathon W

    2017-01-01

    The objective of this study was to understand how people adapt to errors when using a myoelectric control interface. We compared adaptation across 1) non-amputee subjects using joint angle, joint torque, and myoelectric control interfaces, and 2) amputee subjects using myoelectric control interfaces with residual and intact limbs (five total control interface conditions). We measured trial-by-trial adaptation to self-generated errors and random perturbations during a virtual, single degree-of-freedom task with two levels of feedback uncertainty, and evaluated adaptation by fitting a hierarchical Kalman filter model. We have two main results. First, adaptation to random perturbations was similar across all control interfaces, whereas adaptation to self-generated errors differed. These patterns matched predictions of our model, which was fit to each control interface by changing the process noise parameter that represented system variability. Second, in amputee subjects, we found similar adaptation rates and error levels between residual and intact limbs. These results link prosthesis control to broader areas of motor learning and adaptation and provide a useful model of adaptation with myoelectric control. The model of adaptation will help us understand and solve prosthesis control challenges, such as providing additional sensory feedback.

  9. Time-Dependent Noise in GPS Position Time Series By a Network Noise Estimator

    Science.gov (United States)

    Dmitrieva, K.; Segall, P.

    2014-12-01

    Some current estimates of GPS velocity uncertainties for continuous stations with more than a decade of data can be very low, noise, such as random walk. Traditional estimators, based on individual time series, are insensitive to low amplitude random walk, yet such noise significantly increases GPS velocity uncertainties. We develop a new approach to estimating noise in GPS time series, focusing on areas where the signal in the data is well characterized. We analyze data from the seismically inactive parts of central US. The data is decomposed into signal, plate rotation and Glacial Isostatic Adjustment (GIA), and various noise components. Our method processes multiple stations simultaneously with a Kalman Filter, and estimates average noise components for the network by maximum likelihood. Currently, we model white noise, flicker noise and random walk. Synthetic tests show that this approach correctly estimates the velocity uncertainty by determining a good estimate of random walk variance, even when it is too small to be correctly estimated by traditional approaches. We present preliminary results from a network of 15 GPS stations in the central USA. The data is in a North America fixed reference frame, we subtract seasonal components and GIA displacements used in the SNARF model. Hence, all data in this reference frame is treated as noise. We estimate random walk of 0.82 mm/yr0.5, flicker noise of 3.96 mm/yr0.25 and white noise of 1.05 mm. From these noise parameters the estimated velocity uncertainty is 0.29 mm/yr for 10 years of daily data. This uncertainty is significantly greater than estimated by the traditional methods, at 0.12 mm/yr. The estimated uncertainty is still less than the median residual velocity in the North America fixed reference frame, which could indicate that the true uncertainties are even larger. Additionally we estimated noise parameters and velocity uncertainties for the vertical component and for the data with common-mode signal

  10. Moxibustion for the Correction of Nonvertex Presentation: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

    Directory of Open Access Journals (Sweden)

    Qin-hong Zhang

    2013-01-01

    Full Text Available Objectives. This study aims to assess the effectiveness and safety of moxibustion for the correction of nonvertex presentation. Methods. Records without language restrictions were searched up to February 2013 for randomized controlled trials (RCTs comparing moxibustion with other therapies in women with a singleton nonvertex presentation. Cochrane risk of bias criteria were used to assess the methodological quality of the trials. Results. Seven of 392 potentially relevant studies met the inclusion criteria. When moxibustion was compared with other interventions, a meta-analysis revealed a significant difference in favor of moxibustion on the correction of nonvertex presentation at delivery (risk ratio (RR 1.29, 95% confidence interval (CI 1.12 to 1.49, and I2=0. The same findings applied to the cephalic presentation after cessation of treatment (RR 1.36, 95% CI 1.08 to 1.71, and I2=80%. A subgroup analysis that excluded two trials with a high risk of bias also indicated favorable effects (RR 1.63, 95% CI 1.42 to 1.86, and I2=0%. With respect to safety, moxibustion resulted in decreased use of oxytocin. Conclusion. Our systematic review and meta-analysis suggested that moxibustion may be an effective treatment for the correction of nonvertex presentation. Moreover, moxibustion might reduce the need for oxytocin.

  11. The effects of noise vocoding on speech quality perception.

    Science.gov (United States)

    Anderson, Melinda C; Arehart, Kathryn H; Kates, James M

    2014-03-01

    Speech perception depends on access to spectral and temporal acoustic cues. Temporal cues include slowly varying amplitude changes (i.e. temporal envelope, TE) and quickly varying amplitude changes associated with the center frequency of the auditory filter (i.e. temporal fine structure, TFS). This study quantifies the effects of TFS randomization through noise vocoding on the perception of speech quality by parametrically varying the amount of original TFS available above 1500Hz. The two research aims were: 1) to establish the role of TFS in quality perception, and 2) to determine if the role of TFS in quality perception differs between subjects with normal hearing and subjects with sensorineural hearing loss. Ratings were obtained from 20 subjects (10 with normal hearing and 10 with hearing loss) using an 11-point quality scale. Stimuli were processed in three different ways: 1) A 32-channel noise-excited vocoder with random envelope fluctuations in the noise carrier, 2) a 32-channel noise-excited vocoder with the noise-carrier envelope smoothed, and 3) removal of high-frequency bands. Stimuli were presented in quiet and in babble noise at 18dB and 12dB signal-to-noise ratios. TFS randomization had a measurable detrimental effect on quality ratings for speech in quiet and a smaller effect for speech in background babble. Subjects with normal hearing and subjects with sensorineural hearing loss provided similar quality ratings for noise-vocoded speech. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Treatment of preschool children presenting to the emergency department with wheeze with azithromycin: A placebo-controlled randomized trial.

    Directory of Open Access Journals (Sweden)

    Piush J Mandhane

    Full Text Available Antibiotics are frequently used to treat wheezing children. Macrolides may be effective in treating bronchiolitis and asthma.We completed a prospective, double-blinded, randomized placebo-control trial of azithromycin among pre-school children (12 to 60 months of age presenting to the emergency department with wheeze. Patients were randomized to receive either five days of azithromycin or placebo. Primary outcome was time to resolution of respiratory symptoms after treatment initiation. Secondary outcomes included the number of days children used a Short-Acting Beta-Agonists during the 21 day follow-up and time to disease exacerbation during the following six months (unscheduled health care visit or treatment with an oral corticosteroid for acute respiratory symptoms.Of the 300 wheezing children recruited, 222 and 169 were analyzed for the primary and secondary outcomes, respectively. The treatment groups had similar demographics and clinical parameters at baseline. Median time to resolution of respiratory symptoms was four days for both treatment arms (interquartile range (IQR 3,6; p = 0.28. Median number of days of Short-Acting Beta-Agonist use among those who received azithromycin was four and a half days (IQR 2, 7 and five days (IQR 2, 9; p = 0.22 among those who received placebo. Participants who received azithromycin had a 0.91 hazard ratio for time to six-month exacerbation compared to placebo (95% CI 0.61, 1.36, p = 0.65. A pre-determined subgroup analysis showed no differences in outcomes for children with their first or repeat episode of wheezing. There was no significant difference in the proportion of participants experiencing an adverse event.Azithromycin neither reduced duration of respiratory symptoms nor time to respiratory exacerbation in the following six months after treatment among wheezing preschool children presenting to an emergency department. There was no significant effect among children with either first-time or prior

  13. How should the impact of different presentations of treatment effects on patient choice be evaluated? A pilot randomized trial.

    Directory of Open Access Journals (Sweden)

    Cheryl Carling

    Full Text Available BACKGROUND: Different presentations of treatment effects can affect decisions. However, previous studies have not evaluated which presentations best help people make decisions that are consistent with their own values. We undertook a pilot study to compare different methods for doing this. METHODS AND FINDINGS: We conducted an Internet-based randomized trial comparing summary statistics for communicating the effects of statins on the risk of coronary heart disease (CHD. Participants rated the relative importance of treatment consequences using visual analogue scales (VAS and category rating scales (CRS with five response options. We randomized participants to either VAS or CRS first and to one of six summary statistics: relative risk reduction (RRR and five absolute measures of effect: absolute risk reduction, number needed to treat, event rates, tablets needed to take, and natural frequencies (whole numbers. We used logistic regression to determine the association between participants' elicited values and treatment choices. 770 participants age 18 or over and literate in English completed the study. In all, 13% in the VAS-first group failed to complete their VAS rating, while 9% of the CRS-first group failed to complete their scoring (p = 0.03. Different ways of weighting the elicited values had little impact on the analyses comparing the different presentations. Most (51% preferred the RRR compared to the other five summary statistics (1% to 25%, p = 0.074. However, decisions in the group presented the RRR deviated substantially from those made in the other five groups. The odds of participants in the RRR group deciding to take statins were 3.1 to 5.8 times that of those in the other groups across a wide range of values (p = 0.0007. Participants with a scientific background, who were more numerate or had more years of education were more likely to decide not to take statins. CONCLUSIONS: Internet-based trials comparing different presentations

  14. Community response to tramway noise

    NARCIS (Netherlands)

    Miedema, H.M.E.; Berg, R. van den

    1988-01-01

    A study concerning tramway noise is described and results are presented. The study consisted of a social survey and a noise measurement program. It appeared that tramway noise does not contribute to the annoyance of the total noise if tramway annoyance is substantially below road traffic annoyance

  15. Investigation of Allan variance for determining noise spectral forms with application to microwave radiometry

    Science.gov (United States)

    Stanley, William D.

    1994-01-01

    An investigation of the Allan variance method as a possible means for characterizing fluctuations in radiometric noise diodes has been performed. The goal is to separate fluctuation components into white noise, flicker noise, and random-walk noise. The primary means is by discrete-time processing, and the study focused primarily on the digital processes involved. Noise satisfying the requirements was generated by direct convolution, fast Fourier transformation (FFT) processing in the time domain, and FFT processing in the frequency domain. Some of the numerous results obtained are presented along with the programs used in the study.

  16. Improving working memory: exploring the effect of transcranial random noise stimulation and transcranial direct current stimulation on the dorsolateral prefrontal cortex.

    Science.gov (United States)

    Mulquiney, Paul G; Hoy, Kate E; Daskalakis, Zafiris J; Fitzgerald, Paul B

    2011-12-01

    The aim of this study was to determine if working memory (WM) performance is significantly improved after the delivery of transcranial random noise stimulation (tRNS) to the left dorsolateral prefrontal cortex (DLPFC), compared to an active comparator or sham. Ten participants undertook three experimental sessions in which they received 10 min of anodal tDCS (active comparator), tRNS or sham tDCS whilst performing the Sternberg WM task. Intra-stimulation engagement in a WM task was undertaken as this has been previously shown to enhance the effects of tDCS. Experimental sessions were separated by a minimum of 1 week. Immediately prior to and after each stimulation session the participants were measured on speed and accuracy of performance on an n-back task. There was significant improvement in speed of performance following anodal tDCS on the 2-back WM task; this was the only significant finding. The results do not provide support for the hypothesis that tRNS improves WM. However, the study does provide confirmation of previous findings that anodal tDCS enhances some aspects of DLPFC functioning. Methodological limitations that may have contributed to the lack of significant findings following tRNS are discussed. Anodal tDCS may have significant implications for WM remediation in psychiatric conditions, particularly schizophrenia. Copyright © 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  17. Improvement of uncorrected visual acuity (UCVA and contrast sensitivity (UCCS with perceptual learning and transcranial random noise stimulation (tRNS in individuals with mild myopia

    Directory of Open Access Journals (Sweden)

    Rebecca eCamilleri

    2014-10-01

    Full Text Available Perceptual learning has been shown to produce an improvement of visual acuity (VA and contrast sensitivity (CS both in subjects with amblyopia and refractive defects such as myopia or presbyopia. Transcranial random noise stimulation (tRNS has proven to be efficacious in accelerating neural plasticity and boosting perceptual learning in healthy participants. In this study we investigated whether a short behavioural training regime using a contrast detection task combined with online tRNS was as effective in improving visual functions in participants with mild myopia compared to a two-month behavioural training regime without tRNS (Camilleri et al., 2014. After two weeks of perceptual training in combination with tRNS, participants showed an improvement of 0.15 LogMAR in uncorrected VA (UCVA that was comparable with that obtained after eight weeks of training with no tRNS, and an improvement in uncorrected CS (UCCS at various spatial frequencies (whereas no UCCS improvement was seen after eight weeks of training with no tRNS. On the other hand, a control group that trained for two weeks without stimulation did not show any significant UCVA or UCCS improvement. These results suggest that the combination of behavioural and neuromodulatory techniques can be fast and efficacious in improving sight in individuals with mild myopia.

  18. How Random Noise and a Graphical Convention Subverted Behavioral Scientists' Explanations of Self-Assessment Data: Numeracy Underlies Better Alternatives

    Directory of Open Access Journals (Sweden)

    Edward Nuhfer

    2017-01-01

    Full Text Available Despite nearly two decades of research, researchers have not resolved whether people generally perceive their skills accurately or inaccurately. In this paper, we trace this lack of resolution to numeracy, specifically to the frequently overlooked complications that arise from the noisy data produced by the paired measures that researchers employ to determine self-assessment accuracy. To illustrate the complications and ways to resolve them, we employ a large dataset (N = 1154 obtained from paired measures of documented reliability to study self-assessed proficiency in science literacy. We collected demographic information that allowed both criterion-referenced and normative-based analyses of self-assessment data. We used these analyses to propose a quantitatively based classification scale and show how its use informs the nature of self-assessment. Much of the current consensus about peoples' inability to self-assess accurately comes from interpreting normative data presented in the Kruger-Dunning type graphical format or closely related (y - x vs. (x graphical conventions. Our data show that peoples' self-assessments of competence, in general, reflect a genuine competence that they can demonstrate. That finding contradicts the current consensus about the nature of self-assessment. Our results further confirm that experts are more proficient in self-assessing their abilities than novices and that women, in general, self-assess more accurately than men. The validity of interpretations of data depends strongly upon how carefully the researchers consider the numeracy that underlies graphical presentations and conclusions. Our results indicate that carefully measured self-assessments provide valid, measurable and valuable information about proficiency.

  19. Sound localization and occupational noise

    Directory of Open Access Journals (Sweden)

    Pedro de Lemos Menezes

    2014-02-01

    Full Text Available OBJECTIVE: The aim of this study was to determine the effects of occupational noise on sound localization in different spatial planes and frequencies among normal hearing firefighters. METHOD: A total of 29 adults with pure-tone hearing thresholds below 25 dB took part in the study. The participants were divided into a group of 19 firefighters exposed to occupational noise and a control group of 10 adults who were not exposed to such noise. All subjects were assigned a sound localization task involving 117 stimuli from 13 sound sources that were spatially distributed in horizontal, vertical, midsagittal and transverse planes. The three stimuli, which were square waves with fundamental frequencies of 500, 2,000 and 4,000 Hz, were presented at a sound level of 70 dB and were randomly repeated three times from each sound source. The angle between the speaker's axis in the same plane was 45°, and the distance to the subject was 1 m. RESULT: The results demonstrate that the sound localization ability of the firefighters was significantly lower (p<0.01 than that of the control group. CONCLUSION: Exposure to occupational noise, even when not resulting in hearing loss, may lead to a diminished ability to locate a sound source.

  20. The Comparative Analysis of Aversive and Ordinary Noise.

    Science.gov (United States)

    Mobley, C. Marion, Jr.

    There is a vast amount of literature concerning the psychological and physiological effects of ordinary noise on the individual. However, few publications have addressed the analysis of aversive noise. This research analyzes three noises which produce the familiar goose flesh or chilling effect responsivity. These aversive sounds which are made by chalk squeaking on the chalkboard, fingernails on the chalkboard and rubbing styrofoam against a smooth surface are digitally compared to ordinary noise to show how these aversive sounds differ from sounds which are only annoying. This work, which uses Fast Fourier Transform (FFT) analysis is a combination with cross correlation analysis and other innovative methods to produce comparative data on noises, illustrates subtle differences between ordinary and aversive noise which may be useful for future work in acoustics or experimental psychology. The literature review shows disagreement among the numerous works on the effects of ordinary noise on human subjects. One explanation for this difference is the failure to adequately measure and define the dynamic nature of the noise used. The existing literature also establishes that a mixture of tones plus random noise is more annoying (but not aversive) than either the random noise or the tones alone. This investigation shows that one property of aversive noises is the combination of randomness plus tones which vary rapidly with time. This paper utilizes a new digital technique which improves the FFT analyzer resolution by a factor of 25. The resulting +/-2 Hz accuracy facilitated the presentation of frequency variation as a function of time data. Other computer generated graphical data includes the percent harmonic deviation as a function of time, the rate of change of fundamental frequency, and the rate of change in harmonic deviation. From these dynamic data, average values are calculated which show the aversive noise to be consistently greater in mean frequency deviation

  1. Seismic noise attenuation using an online subspace tracking algorithm

    Science.gov (United States)

    Zhou, Yatong; Li, Shuhua; Zhang, Dong; Chen, Yangkang

    2018-02-01

    We propose a new low-rank based noise attenuation method using an efficient algorithm for tracking subspaces from highly corrupted seismic observations. The subspace tracking algorithm requires only basic linear algebraic manipulations. The algorithm is derived by analysing incremental gradient descent on the Grassmannian manifold of subspaces. When the multidimensional seismic data are mapped to a low-rank space, the subspace tracking algorithm can be directly applied to the input low-rank matrix to estimate the useful signals. Since the subspace tracking algorithm is an online algorithm, it is more robust to random noise than traditional truncated singular value decomposition (TSVD) based subspace tracking algorithm. Compared with the state-of-the-art algorithms, the proposed denoising method can obtain better performance. More specifically, the proposed method outperforms the TSVD-based singular spectrum analysis method in causing less residual noise and also in saving half of the computational cost. Several synthetic and field data examples with different levels of complexities demonstrate the effectiveness and robustness of the presented algorithm in rejecting different types of noise including random noise, spiky noise, blending noise, and coherent noise.

  2. Noise in the operating room

    DEFF Research Database (Denmark)

    Hasfeldt-Hansen, Dorthe; Lærkner, Eva Ann; Birkelund, Regner

    2010-01-01

    Because noise is a general stressor, noise in the OR should be avoided whenever possible. This article presents the results of a review of the research literature on the topic of noise in the OR. A systematic literature search was conducted. Eighteen relevant articles were identified...... and categorized as follows: noise levels, noise sources, staff performances, and patient’s perception of noise. Each study was assessed according to the strength of the evidence and the quality of the study. Noise levels in the OR in general exceed recommended levels, and the noise sources are related...... to equipment and staff behavior. The main effect of noise on staff performances is related to impaired communication, resulting in a negative effect on patient safety. The literature on patients’ perception of noise is both limited and inconsistent, and more research on this topic is needed....

  3. Noise Pollution

    Science.gov (United States)

    ... primarily to one’s overall health. Top of Page Health Effects Noise pollution adversely affects the lives of millions of people. ... its effect, disseminate information to the public regarding noise pollution and its adverse health effects, respond to inquiries on matters related to noise, ...

  4. The Importance of Spatiotemporal Information in Biological Motion Perception: White Noise Presented with a Step-like Motion Activates the Biological Motion Area.

    Science.gov (United States)

    Callan, Akiko; Callan, Daniel; Ando, Hiroshi

    2017-02-01

    Humans can easily recognize the motion of living creatures using only a handful of point-lights that describe the motion of the main joints (biological motion perception). This special ability to perceive the motion of animate objects signifies the importance of the spatiotemporal information in perceiving biological motion. The posterior STS (pSTS) and posterior middle temporal gyrus (pMTG) region have been established by many functional neuroimaging studies as a locus for biological motion perception. Because listening to a walking human also activates the pSTS/pMTG region, the region has been proposed to be supramodal in nature. In this study, we investigated whether the spatiotemporal information from simple auditory stimuli is sufficient to activate this biological motion area. We compared spatially moving white noise, having a running-like tempo that was consistent with biological motion, with stationary white noise. The moving-minus-stationary contrast showed significant differences in activation of the pSTS/pMTG region. Our results suggest that the spatiotemporal information of the auditory stimuli is sufficient to activate the biological motion area.

  5. Physiological, Psychological, and Social Effects of Noise

    Science.gov (United States)

    Kryter, K. D.

    1984-01-01

    The physiological, and behavioral effects of noise on man are investigated. Basic parameters such as definitions of noise, measuring techniques of noise, and the physiology of the ear are presented prior to the development of topics on hearing loss, speech communication in noise, social effects of noise, and the health effects of noise pollution. Recommendations for the assessment and subsequent control of noise is included.

  6. Classical noise, quantum noise and secure communication

    Science.gov (United States)

    Tannous, C.; Langlois, J.

    2016-01-01

    Secure communication based on message encryption might be performed by combining the message with controlled noise (called pseudo-noise) as performed in spread-spectrum communication used presently in Wi-Fi and smartphone telecommunication systems. Quantum communication based on entanglement is another route for securing communications as demonstrated by several important experiments described in this work. The central role played by the photon in unifying the description of classical and quantum noise as major ingredients of secure communication systems is highlighted and described on the basis of the classical and quantum fluctuation dissipation theorems.

  7. Noise upon the Sinusoids

    DEFF Research Database (Denmark)

    Jensen, Karl Kristoffer

    2005-01-01

    Sinusoids are used for making harmonic and other sounds. In order to having life in the sounds and adding a wide variety of noises, irregularities are inserted in the frequency and amplitudes. A simple and intuitive noise model is presented, consisting of a low-pass filtered noise, and having...... control for strength and bandwidth. The noise is added on the frequency and amplitudes of the sinusoids, and the resulting irregularity’s (jitter and shimmer) bandwidth is derived. This, together with an overview of investigation methods of the jitter and shimmer results in an analysis of the necessary...

  8. Self-generation and positivity effects following transcranial random noise stimulation in medial prefrontal cortex: A reality monitoring task in older adults.

    Science.gov (United States)

    Mammarella, Nicola; Di Domenico, Alberto; Palumbo, Rocco; Fairfield, Beth

    2017-06-01

    Activation of medial Prefrontal Cortex (mPFC) has been typically found during reality monitoring tasks (i.e., distinguishing between internal self-generated vs external information). No study, however, has yet investigated whether transcranial Random Noise Stimulation (tRNS) over the mPFC leads to a reduction in reality-monitoring misattributions in aging. In particular, stimulating mPFC should increase the number of cognitive operations engaged while encoding and this distinctive information may help older adults to discriminate between internal and external sources better. In addition, given that older adults are more sensitive to positively-charged information compared to younger adults and that mPFC is typically recruited during encoding of positive stimuli with reference to themselves, activation of mPFC should further sustain source retrieval in older adults. In this double-blind, sham-controlled study, we examined whether tRNS over the mPFC of healthy younger and older adults during encoding enhances subsequent reality monitoring for seen versus imagined emotionally-charged words. Our findings show that tRNS enhances reality monitoring for positively-charged imagined words in the older adult group alone, highlighting the role that mPFC plays in their memory for positive information. In line with the control-based account of positivity effects, our results add evidence about the neurocognitive processes involved in reality monitoring when older adults face emotionally-charged events. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Between Noise and Silence: Architecture since the 1970s

    Directory of Open Access Journals (Sweden)

    Alexandra Brown

    2012-12-01

    Full Text Available This essay considers noise in architectural discourse as it might lend form to issues hitherto tabled in rather different terms. We ask what noise offers this discussion or, perhaps better put, what seeing architectural debates in terms of distinctions between noise and silence, random and structured sound, silence as absence and pregnant void might add to disciplinary debates within architectural theory and criticism. By treating these acoustic values analogously rather than literally we wish to suggest that reading the late postmodern moment through this filter opens out new possibilities for a critical assessment of this period and its present-day legacies.

  10. Railroad Noise: Economic Valuation and Policy

    NARCIS (Netherlands)

    Brons, M.R.E.; Nijkamp, P.; Pels, E.; Rietveld, P.

    2003-01-01

    In developed countries noise annoyance is an important source of environmental concern. Research on noise annoyance caused by railroad traffic is relatively underdeveloped. Here, a causal chain model is presented in which railroad traffic density, noise emission, noise immission and noise annoyance

  11. Noise equivalent circuit of a semiconductor laser diode

    Science.gov (United States)

    Harder, C.; Margalit, S.; Yariv, A.; Katz, J.; Shacham, J.

    1982-01-01

    A small-signal model of a semiconductor laser is extended to include the effects of intrinsic noise by adding current and voltage noise sources. The current noise source represents the shot noise of carrier recombination, while the voltage noise source represents the random process of simulated emission. The usefulness of the noise equivalent circuit is demonstrated by calculating the modulation and noise characteristics of a current-driven diode as a function of bias current and frequency.

  12. Noise equivalent circuit of a semiconductor laser diode

    Science.gov (United States)

    Harder, C.; Margalit, S.; Yariv, A.; Katz, J.; Shacham, J.

    1982-03-01

    A small-signal model of a semiconductor laser is extended to include the effects of intrinsic noise by adding current and voltage noise sources. The current noise source represents the shot noise of carrier recombination, while the voltage noise source represents the random process of simulated emission. The usefulness of the noise equivalent circuit is demonstrated by calculating the modulation and noise characteristics of a current-driven diode as a function of bias current and frequency.

  13. Quantum coin tossing and bit-string generation in the presence of noise

    Science.gov (United States)

    Barrett, Jonathan; Massar, Serge

    2004-02-01

    We discuss the security implications of noise for quantum coin tossing protocols. We find that if quantum error correction can be used, so that noise levels can be made arbitrarily small, then reasonable security conditions for coin tossing can be framed so that results from the noiseless case will continue to hold. If, however, error correction is not available (as is the case with present day technology), and significant noise is present, then tossing a single coin becomes problematic. In this case, we are led to consider random n-bit string generation in the presence of noise, rather than single-shot coin tossing. We introduce precise security criteria for n-bit string generation and describe an explicit protocol that could be implemented with present day technology. In general, a cheater can exploit noise in order to bias coins to their advantage. We derive explicit upper bounds on the average bias achievable by a cheater for given noise levels.

  14. Neuroanatomical substrate of noise sensitivity

    DEFF Research Database (Denmark)

    Kliuchko, Marina; Puoliväli, Tuomas; Heinonen-Guzejev, Marja

    2018-01-01

    Recent functional studies suggest that noise sensitivity, a trait describing attitudes towards noise and predicting noise annoyance, is associated with altered processing in the central auditory system. In the present work, we examined whether noise sensitivity could be related to the structural...... and hippocampus was measured as well. According to our findings, noise sensitivity is associated with the grey matter volume in the selected structures. Among those, we propose and discuss particular areas, previously linked to auditory perceptual, emotional and interoceptive processing, in which larger grey...... matter volume seems to be related to higher noise sensitivity....

  15. Annoyance of low frequency noise and traffic noise

    DEFF Research Database (Denmark)

    Mortensen, F.R.; Poulsen, Torben

    2001-01-01

    The annoyance of different low frequency noise sources was determined and compared to the annoyance from traffic noise. Twenty-two subjects participated in laboratory listening tests. The sounds were presented by loudspeakers in a listening room and the spectra of the low frequency noises were...

  16. Annoyance of low frequency noise and traffic noise

    DEFF Research Database (Denmark)

    Mortensen, Frank Rysgaard; Poulsen, Torben

    2000-01-01

    The annoyance of different low frequency noise sources was determined and compared to the annoyance from traffic noise. Twenty-two test subjects participated in laboratory listening tests. The sounds were presented by loudspeakers in a listening room and the spectra of the low frequency noises were...

  17. Noise Protection

    Science.gov (United States)

    1980-01-01

    Environmental Health Systems puts forth an increasing effort in the U.S. to develop ways of controlling noise, particularly in industrial environments due to Federal and State laws, labor union insistence and new findings relative to noise pollution impact on human health. NASA's Apollo guidance control system aided in the development of a noise protection product, SMART. The basis of all SMART products is SMART compound a liquid plastic mixture with exceptional energy/sound absorbing qualities. The basic compound was later refined for noise protection use.

  18. Weak localization of photon noise

    NARCIS (Netherlands)

    Scalia, Paolo S.; Muskens, Otto L.; Lagendijk, Aart

    2013-01-01

    We present an experimental study of coherent backscattering (CBS) of photon noise from multiple scattering media. We use a pseudothermal light source with a microsecond coherence time to produce a noise spectrum covering a continuous transition, from wave fluctuations to shot noise over several MHz.

  19. Noise mapping inside a car

    Science.gov (United States)

    Strekalov, V. A.; Shaimuhametov, R. R.

    2017-09-01

    We present new wireless sensor telemetry system designed to be mounted on different nodes of the car and record acoustic noises. The proposed system is mapping noise inside a car. The noise field is recorded at the ten control regions simultaneously.

  20. The incidence of the different sources of noise on the uncertainty in radiochromic film dosimetry using single channel and multichannel methods

    Science.gov (United States)

    González-López, Antonio; Vera-Sánchez, Juan Antonio; Ruiz-Morales, Carmen

    2017-11-01

    The influence of the various sources of noise on the uncertainty in radiochromic film (RCF) dosimetry using single channel and multichannel methods is investigated in this work. These sources of noise are extracted from pixel value (PV) readings and dose maps. Pieces of an RCF were each irradiated to different uniform doses, ranging from 0 to 1092 cGy. Then, the pieces were read at two resolutions (72 and 150 ppp) with two flatbed scanners: Epson 10000XL and Epson V800, representing two states of technology. Noise was extracted as described in ISO 15739 (2013), separating its distinct constituents: random noise and fixed pattern (FP) noise. Regarding the PV maps, FP noise is the main source of noise for both models of digitizer. Also, the standard deviation of the random noise in the 10000XL model is almost twice that of the V800 model. In the dose maps, the FP noise is smaller in the multichannel method than in the single channel ones. However, random noise is higher in this method, throughout the dose range. In the multichannel method, FP noise is reduced, as a consequence of this method’s ability to eliminate channel independent perturbations. However, the random noise increases, because the dose is calculated as a linear combination of the doses obtained by the single channel methods. The values of the coefficients of this linear combination are obtained in the present study, and the root of the sum of their squares is shown to range between 0.9 and 1.9 over the dose range studied. These results indicate the random noise to play a fundamental role in the uncertainty of RCF dosimetry: low levels of random noise are required in the digitizer to fully exploit the advantages of the multichannel dosimetry method. This is particularly important for measuring high doses at high spatial resolutions.

  1. Clustering of noise-induced oscillations

    DEFF Research Database (Denmark)

    Sosnovtseva, Olga; Fomin, A I; Postnov, D E

    2001-01-01

    The subject of our study is clustering in a population of excitable systems driven by Gaussian white noise and with randomly distributed coupling strength. The cluster state is frequency-locked state in which all functional units run at the same noise-induced frequency. Cooperative dynamics...... of this regime is described in terms of effective synchronization and noise-induced coherence....

  2. Classroom Noise and Teachers' Voice Production

    Science.gov (United States)

    Rantala, Leena M.; Hakala, Suvi; Holmqvist, Sofia; Sala, Eeva

    2015-01-01

    Purpose: The aim of this study was to research the associations between noise (ambient and activity noise) and objective metrics of teachers' voices in real working environments (i.e., classrooms). Method: Thirty-two female and 8 male teachers from 14 elementary schools were randomly selected for the study. Ambient noise was measured during breaks…

  3. Noise management by molecular networks.

    Directory of Open Access Journals (Sweden)

    Frank J Bruggeman

    2009-09-01

    Full Text Available Fluctuations in the copy number of key regulatory macromolecules ("noise" may cause physiological heterogeneity in populations of (isogenic cells. The kinetics of processes and their wiring in molecular networks can modulate this molecular noise. Here we present a theoretical framework to study the principles of noise management by the molecular networks in living cells. The theory makes use of the natural, hierarchical organization of those networks and makes their noise management more understandable in terms of network structure. Principles governing noise management by ultrasensitive systems, signaling cascades, gene networks and feedback circuitry are discovered using this approach. For a few frequently occurring network motifs we show how they manage noise. We derive simple and intuitive equations for noise in molecule copy numbers as a determinant of physiological heterogeneity. We show how noise levels and signal sensitivity can be set independently in molecular networks, but often changes in signal sensitivity affect noise propagation. Using theory and simulations, we show that negative feedback can both enhance and reduce noise. We identify a trade-off; noise reduction in one molecular intermediate by negative feedback is at the expense of increased noise in the levels of other molecules along the feedback loop. The reactants of the processes that are strongly (cooperatively regulated, so as to allow for negative feedback with a high strength, will display enhanced noise.

  4. Noise sensitivity and road traffic annoyance in a population sample

    Science.gov (United States)

    Matsumura, Y.; Rylander, R.

    1991-12-01

    Noise sensitivity was studied in a random sample of the population of Gothenburg, Sweden. The selected population of 805 persons received a mailed questionnaire comprising questions on self-reported noise sensitivity, attitudes to noise, annoyance due to environmental noises and the effect of noise on daily activities. The response rate was 56%. Noise sensitivity was most common in older age groups. Noise-sensitive individuals were more annoyed by road traffic noise, and also reported interference with daily activities to a higher extent than non-sensitive persons. Listening to music while working or reading was also less common in the noise-sensitive group.

  5. Noise-Compensated, Bias-Corrected Diffusion Weighted Endorectal Magnetic Resonance Imaging via a Stochastically Fully-Connected Joint Conditional Random Field Model

    CERN Document Server

    Boroomand, Ameneh; Khalvati, Farzad; Haider, Masoom A; Wong, Alexander

    2015-01-01

    Diffusion weighted magnetic resonance imaging (DW-MRI) is a powerful tool in imaging-based prostate cancer (PCa) screening and detection. Endorectal coils are commonly used in DW-MRI to improve the signal-to-noise ratio (SNR) of the acquisition, at the expense of significant intensity inhomogeneities (bias field) that worsens as we move away from the endorectal coil. The presence of bias field can have a significant negative impact on the accuracy of different image analysis tasks, as well as the accuracy of PCa tumor localization, thus leading to increased inter- and intra-observer variability. The previously proposed bias field correction methods often suffer from undesired noise amplification that can reduce the image quality of the resulting bias-corrected DW-MRI data. Here, we propose a unified data reconstruction approach that enables joint compensation of bias field as well as data noise in diffusion weighted endorectal magnetic resonance (DW-EMR) imaging. The proposed noise-compensated, bias-corrected...

  6. Visual presentations of efficacy data in direct-to-consumer prescription drug print and television advertisements: A randomized study.

    Science.gov (United States)

    Sullivan, Helen W; O'Donoghue, Amie C; Aikin, Kathryn J; Chowdhury, Dhuly; Moultrie, Rebecca R; Rupert, Douglas J

    2016-05-01

    To determine whether visual aids help people recall quantitative efficacy information in direct-to-consumer (DTC) prescription drug advertisements, and if so, which types of visual aids are most helpful. Individuals diagnosed with high cholesterol (n=2504) were randomized to view a fictional DTC print or television advertisement with no visual aid or one of four visual aids (pie chart, bar chart, table, or pictograph) depicting drug efficacy. We measured drug efficacy and risk recall, drug perceptions and attitudes, and behavioral intentions. For print advertisements, a bar chart or table, compared with no visual aid, elicited more accurate drug efficacy recall. The bar chart was better at this than the pictograph and the table was better than the pie chart. For television advertisements, any visual aid, compared with no visual aid, elicited more accurate drug efficacy recall. The bar chart was better at this than the pictograph or the table. Visual aids depicting quantitative efficacy information in DTC print and television advertisements increased drug efficacy recall, which may help people make informed decisions about prescription drugs. Adding visual aids to DTC advertising may increase the public's knowledge of how well prescription drugs work. Published by Elsevier Ireland Ltd.

  7. Stochastic bifurcation in a model of love with colored noise

    Science.gov (United States)

    Yue, Xiaokui; Dai, Honghua; Yuan, Jianping

    2015-07-01

    In this paper, we wish to examine the stochastic bifurcation induced by multiplicative Gaussian colored noise in a dynamical model of love where the random factor is used to describe the complexity and unpredictability of psychological systems. First, the dynamics in deterministic love-triangle model are considered briefly including equilibrium points and their stability, chaotic behaviors and chaotic attractors. Then, the influences of Gaussian colored noise with different parameters are explored such as the phase plots, top Lyapunov exponents, stationary probability density function (PDF) and stochastic bifurcation. The stochastic P-bifurcation through a qualitative change of the stationary PDF will be observed and bifurcation diagram on parameter plane of correlation time and noise intensity is presented to find the bifurcation behaviors in detail. Finally, the top Lyapunov exponent is computed to determine the D-bifurcation when the noise intensity achieves to a critical value. By comparison, we find there is no connection between two kinds of stochastic bifurcation.

  8. Airframe noise prediction evaluation

    Science.gov (United States)

    Yamamoto, Kingo J.; Donelson, Michael J.; Huang, Shumei C.; Joshi, Mahendra C.

    1995-01-01

    The objective of this study is to evaluate the accuracy and adequacy of current airframe noise prediction methods using available airframe noise measurements from tests of a narrow body transport (DC-9) and a wide body transport (DC-10) in addition to scale model test data. General features of the airframe noise from these aircraft and models are outlined. The results of the assessment of two airframe prediction methods, Fink's and Munson's methods, against flight test data of these aircraft and scale model wind tunnel test data are presented. These methods were extensively evaluated against measured data from several configurations including clean, slat deployed, landing gear-deployed, flap deployed, and landing configurations of both DC-9 and DC-10. They were also assessed against a limited number of configurations of scale models. The evaluation was conducted in terms of overall sound pressure level (OASPL), tone corrected perceived noise level (PNLT), and one-third-octave band sound pressure level (SPL).

  9. High level white noise generator

    Science.gov (United States)

    Borkowski, Casimer J.; Blalock, Theron V.

    1979-01-01

    A wide band, stable, random noise source with a high and well-defined output power spectral density is provided which may be used for accurate calibration of Johnson Noise Power Thermometers (JNPT) and other applications requiring a stable, wide band, well-defined noise power spectral density. The noise source is based on the fact that the open-circuit thermal noise voltage of a feedback resistor, connecting the output to the input of a special inverting amplifier, is available at the amplifier output from an equivalent low output impedance caused by the feedback mechanism. The noise power spectral density level at the noise source output is equivalent to the density of the open-circuit thermal noise or a 100 ohm resistor at a temperature of approximately 64,000 Kelvins. The noise source has an output power spectral density that is flat to within 0.1% (0.0043 db) in the frequency range of from 1 KHz to 100 KHz which brackets typical passbands of the signal-processing channels of JNPT's. Two embodiments, one of higher accuracy that is suitable for use as a standards instrument and another that is particularly adapted for ambient temperature operation, are illustrated in this application.

  10. Adjusting phenotypes by noise control.

    Directory of Open Access Journals (Sweden)

    Kyung H Kim

    2012-01-01

    Full Text Available Genetically identical cells can show phenotypic variability. This is often caused by stochastic events that originate from randomness in biochemical processes involving in gene expression and other extrinsic cellular processes. From an engineering perspective, there have been efforts focused on theory and experiments to control noise levels by perturbing and replacing gene network components. However, systematic methods for noise control are lacking mainly due to the intractable mathematical structure of noise propagation through reaction networks. Here, we provide a numerical analysis method by quantifying the parametric sensitivity of noise characteristics at the level of the linear noise approximation. Our analysis is readily applicable to various types of noise control and to different types of system; for example, we can orthogonally control the mean and noise levels and can control system dynamics such as noisy oscillations. As an illustration we applied our method to HIV and yeast gene expression systems and metabolic networks. The oscillatory signal control was applied to p53 oscillations from DNA damage. Furthermore, we showed that the efficiency of orthogonal control can be enhanced by applying extrinsic noise and feedback. Our noise control analysis can be applied to any stochastic model belonging to continuous time Markovian systems such as biological and chemical reaction systems, and even computer and social networks. We anticipate the proposed analysis to be a useful tool for designing and controlling synthetic gene networks.

  11. Auditory white noise reduces age-related fluctuations in balance.

    Science.gov (United States)

    Ross, J M; Will, O J; McGann, Z; Balasubramaniam, R

    2016-09-06

    Fall prevention technologies have the potential to improve the lives of older adults. Because of the multisensory nature of human balance control, sensory therapies, including some involving tactile and auditory noise, are being explored that might reduce increased balance variability due to typical age-related sensory declines. Auditory white noise has previously been shown to reduce postural sway variability in healthy young adults. In the present experiment, we examined this treatment in young adults and typically aging older adults. We measured postural sway of healthy young adults and adults over the age of 65 years during silence and auditory white noise, with and without vision. Our results show reduced postural sway variability in young and older adults with auditory noise, even in the absence of vision. We show that vision and noise can reduce sway variability for both feedback-based and exploratory balance processes. In addition, we show changes with auditory noise in nonlinear patterns of sway in older adults that reflect what is more typical of young adults, and these changes did not interfere with the typical random walk behavior of sway. Our results suggest that auditory noise might be valuable for therapeutic and rehabilitative purposes in older adults with typical age-related balance variability. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  12. Measurement and analyses of spectral noise power in computed tomography; Medida y analisis del espectro de potencias del ruido en imagenes de tomografia computarizada

    Energy Technology Data Exchange (ETDEWEB)

    Castro Tejero, P.; Garayoa Roca, J.

    2014-07-01

    Noise is an important feature of image quality. The standard deviation of pixel value in a uniform region has been frequently used as a metric to characterize noise. However, this measure does not provide any information about the noise spatial distribution. A more complete description is given by the Noise Power Spectrum (NPS) which provides both the amount and the spatial correlation of noise. The objective of the present work is to present a methodology and a computing tool to obtain the NPS, in order to analyze its components and study their behaviour for computed tomography (TC) images. Our results show that the major contribution to NPS is a random source for all the explored working conditions. The structural component is constrained to the low frequency region, where it can be as important as the random component. Moreover, we observe that the reconstruction filter and the acquisition technique, axial or helical, have a clear impact on the image noise. (Author)

  13. Long-acting reversible contraceptive acceptability and unintended pregnancy among women presenting for short-acting methods: a randomized patient preference trial.

    Science.gov (United States)

    Hubacher, David; Spector, Hannah; Monteith, Charles; Chen, Pai-Lien; Hart, Catherine

    2017-02-01

    participants, 43% chose randomization and 57% chose the preference option. Complete loss to follow-up at 12 months was 90%). Even in a typical population of women who presented to initiate or continue short-acting reversible contraception, long-acting reversible contraception proved highly acceptable. One year after initiation, women randomized to long-acting reversible contraception had high continuation rates and consequently experienced superior protection from unintended pregnancy compared with women using short-acting reversible contraception; these findings are attributable to the initial technology and not underlying factors that often bias observational estimates of effectiveness. The similarly patterned experiences of the 2 short-acting reversible contraception cohorts provide a bridge of generalizability between the randomized group and usual-care preference group. Benefits of increased voluntary uptake of long-acting reversible contraception may extend to wider populations than previously thought. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Active noise control primer

    CERN Document Server

    Snyder, Scott D

    2000-01-01

    Active noise control - the reduction of noise by generating an acoustic signal that actively interferes with the noise - has become an active area of basic research and engineering applications. The aim of this book is to present all of the basic knowledge one needs for assessing how useful active noise control will be for a given problem and then to provide some guidance for designing, setting up, and tuning an active noise-control system. Written for students who have no prior knowledge of acoustics, signal processing, or noise control but who do have a reasonable grasp of basic physics and mathematics, the book is short and descriptive. It leaves for more advanced texts or research monographs all mathematical details and proofs concerning vibrations, signal processing and the like. The book can thus be used in independent study, in a classroom with laboratories, or in conjunction with a kit for experiment or demonstration. Topics covered include: basic acoustics; human perception and sound; sound intensity...

  15. Noise map of cities and agglomerations

    OpenAIRE

    N.A. Lapteva; I.I. Bogolepov

    2010-01-01

    Noise map of city is an instrument for noise control. There are noise levels on all main roads, in people habitation and recreation areas, on the territory of industrial and other enterprises, and around isolated noisy objects. At present time in Russia and abroad the main problem of noise maps is as before the indefinite precision and reliability of indicated value of noise levels. With using of variance analysis method of probability theory and mathematical statistics the authors propose a ...

  16. Random walks on three-strand braids and on related hyperbolic groups 05.40.-a Fluctuation phenomena, random processes, noise, and Brownian motion; 02.50.-r Probability theory, stochastic processes, and statistics; 02.40.Ky Riemannian geometries;

    CERN Document Server

    Nechaev, S

    2003-01-01

    We investigate the statistical properties of random walks on the simplest nontrivial braid group B sub 3 , and on related hyperbolic groups. We provide a method using Cayley graphs of groups allowing us to compute explicitly the probability distribution of the basic statistical characteristics of random trajectories - the drift and the return probability. The action of the groups under consideration in the hyperbolic plane is investigated, and the distribution of a geometric invariant - the hyperbolic distance - is analysed. It is shown that a random walk on B sub 3 can be viewed as a 'magnetic random walk' on the group PSL(2, Z).

  17. Random walks on three-strand braids and on related hyperbolic groups[05.40.-a Fluctuation phenomena, random processes, noise, and Brownian motion; 02.50.-r Probability theory, stochastic processes, and statistics; 02.40.Ky Riemannian geometries;

    Energy Technology Data Exchange (ETDEWEB)

    Nechaev, Sergei [Laboratoire de Physique Theorique et Modeles Statistiques, Universite Paris Sud, 91405 Orsay Cedex (France); Voituriez, Raphael [Laboratoire de Physique Theorique et Modeles Statistiques, Universite Paris Sud, 91405 Orsay Cedex (France)

    2003-01-10

    We investigate the statistical properties of random walks on the simplest nontrivial braid group B{sub 3}, and on related hyperbolic groups. We provide a method using Cayley graphs of groups allowing us to compute explicitly the probability distribution of the basic statistical characteristics of random trajectories - the drift and the return probability. The action of the groups under consideration in the hyperbolic plane is investigated, and the distribution of a geometric invariant - the hyperbolic distance - is analysed. It is shown that a random walk on B{sub 3} can be viewed as a 'magnetic random walk' on the group PSL(2, Z)

  18. Assessment of Traffic Noise Impacts

    DEFF Research Database (Denmark)

    Rich, Jeppe Husted; Nielsen, Otto Anker

    2004-01-01

    the true social benefit of infrastructure plans. The paper presents a noise assessment model for the Copenhagen region, which brings together GIS technology and non-linear hedonic regression models to reveal the implicit costs of traffic noise measured as the marginal percentage loss in property values...... with respect to the decibel traffic noise. The model distinguishes between houses and apartments and shows that the ability to include refined accessibility variables have significant impact on estimated prices....

  19. A Comparative Effectiveness Trial of Alternate Formats for Presenting Benefits and Harms Information for Low-Value Screening Services: A Randomized Clinical Trial.

    Science.gov (United States)

    Sheridan, Stacey L; Sutkowi-Hemstreet, Anne; Barclay, Colleen; Brewer, Noel T; Dolor, Rowena J; Gizlice, Ziya; Lewis, Carmen L; Reuland, Daniel S; Golin, Carol E; Kistler, Christine E; Vu, Maihan; Harris, Russell

    2016-01-01

    Healthcare overuse, the delivery of low-value services, is increasingly recognized as a critical problem. However, little is known about the comparative effectiveness of alternate formats for presenting benefits and harms information to patients as a strategy to reduce overuse. To examine the effect of different benefits and harms presentations on patients' intentions to accept low-value or potentially low-value screening services (prostate cancer screening in men ages 50-69 years; osteoporosis screening in low-risk women ages 50-64 years; or colorectal cancer screening in men and women ages 76-85 years). Randomized clinical trial of 775 individuals eligible to receive information about any 1 of the 3 screening services and scheduled for a visit with their clinician. Participants were randomized to 1 of 4 intervention arms that differed in terms of presentation format: words, numbers, numbers plus narrative, and numbers plus framed presentation. The trial was conducted from September 2012 to June 2014 at 2 family medicine and 2 internal medicine practices affiliated with the Duke Primary Care Research Consortium. The data were analyzed between May and September of 2015. One-page evidence-based decision support sheets on each of the 3 screening services, with benefits and harms information presented in 1 of 4 formats: words, numbers, numbers plus narratives, or numbers plus a framed presentation. The primary outcome was change in intention to accept screening (on a response scale from 1 to 5). Our secondary outcomes included general and disease-specific knowledge, perceived risk and consequences of disease, screening attitudes, perceived net benefit of screening, values clarity, and self-efficacy for screening. We enrolled and randomly allocated 775 individuals, aged 50 to 85 years, to 1 of 4 intervention arms: 195 to words, 192 to numbers, 196 to narrative, and 192 to framed formats. Intentions to accept screening were high before the intervention and

  20. The subjective importance of noise spectral content

    Science.gov (United States)

    Baxter, Donald; Phillips, Jonathan; Denman, Hugh

    2014-01-01

    This paper presents secondary Standard Quality Scale (SQS2) rankings in overall quality JNDs for a subjective analysis of the 3 axes of noise, amplitude, spectral content, and noise type, based on the ISO 20462 softcopy ruler protocol. For the initial pilot study, a Python noise simulation model was created to generate the matrix of noise masks for the softcopy ruler base images with different levels of noise, different low pass filter noise bandwidths and different band pass filter center frequencies, and 3 different types of noise: luma only, chroma only, and luma and chroma combined. Based on the lessons learned, the full subjective experiment, involving 27 observers from Google, NVIDIA and STMicroelectronics was modified to incorporate a wider set of base image scenes, and the removal of band pass filtered noise masks to ease observer fatigue. Good correlation was observed with the Aptina subjective noise study. The absence of tone mapping in the noise simulation model visibly reduced the contrast at high levels of noise, due to the clipping of the high levels of noise near black and white. Under the 34-inch viewing distance, no significant difference was found between the luma only noise masks and the combined luma and chroma noise masks. This was not the intuitive expectation. Two of the base images with large uniform areas, `restaurant' and `no parking', were found to be consistently more sensitive to noise than the texture rich scenes. Two key conclusions are (1) there are fundamentally different sensitivities to noise on a flat patch versus noise in real images and (2) magnification of an image accentuates visual noise in a way that is non-representative of typical noise reduction algorithms generating the same output frequency. Analysis of our experimental noise masks applied to a synthetic Macbeth ColorChecker Chart confirmed the color-dependent nature of the visibility of luma and chroma noise.

  1. Intracoronary Eptifibatide During Primary Percutaneous Coronary Intervention in Early Versus Late Presenters with ST Segment Elevation Myocardial Infarction: A Randomized Trial.

    Science.gov (United States)

    Elbadawi, Ayman; Gasioch, Gerald; Elgendy, Islam Y; Mahmoud, Ahmed N; Ha, Le Dung; Ashry, Haitham Al; Shahin, Hend; Hamza, Mohamed A; Abuzaid, Ahmed S; Saad, Marwan

    2016-12-01

    The role of intracoronary (IC) eptifibatide in primary percutaneous coronary intervention (PPCI) for ST segment elevation myocardial infarction (STEMI) and whether time of patient presentation affects this role are unclear. We sought to evaluate the benefit of IC eptifibatide use during primary PCI in early STEMI presenters compared to late STEMI presenters. We included 70 patients who presented with STEMI and were eligible for PPCI. On the basis of symptom-to-door time, patients were classified into two arms: early (eptifibatide infusion vs standard care (control group). The primary end point was post-PCI myocardial blush grade (MBG) in the culprit vessel. Other end points included corrected TIMI frame count (cTFC), ST segment resolution (STR) ≥70%, and peak CKMB. In the early presenters arm, no difference was observed in MBG results ≥2 in the IC eptifibatide and control groups (100% vs 82%; p = 0.23). In the late presenters arm, the eptifibatide subgroup was associated with improved MBG ≥2 (100% vs 50%; p = 0.001). IC eptifibatide in both early and late presenters was associated with less cTFC (early presenters 19 vs. 25.6, p = 0.001; late presenters 20 vs. 31.5, p eptifibatide might improve the reperfusion markers during PPCI for STEMI patients presenting after 3 h from onset of symptoms. A large randomized study is recommended to ascertain the benefits of IC eptifibatide in late presenters on clinical outcomes.

  2. Investigation of trap properties in high-k/metal gate p-type metal-oxide-semiconductor field-effect-transistors with aluminum ion implantation using random telegraph noise analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kao, Tsung-Hsien; Chang, Shoou-Jinn, E-mail: changsj@mail.ncku.edu.tw; Fang, Yean-Kuen; Huang, Po-Chin [Institute of Microelectronics and Department of Electrical Engineering, Advanced Optoelectronic Technology Center, Center for Micro/Nano Science and Technology, National Cheng Kung University, No. 1, University Road, Tainan 701, Taiwan (China); Lai, Chien-Ming; Hsu, Chia-Wei; Chen, Yi-Wen; Cheng, Osbert [Central R and D Division, United Microelectronics Corporation, Ltd., Tainan Science-Based Industrial Park, Tainan 74145, Taiwan (China); Wu, Chung-Yi; Wu, San-Lein [Department of Electronic Engineering, Cheng Shiu University, 840 Chengcing Road, Niaosong, Kaohsiung 833, Taiwan (China)

    2014-08-11

    In this study, the impact of aluminum ion implantation (Al I/I) on random telegraph noise (RTN) in high-k/metal gate (HK/MG) p-type metal-oxide-semiconductor field-effect-transistors (pMOSFETs) was investigated. The trap parameters of HK/MG pMOSFETs with Al I/I, such as trap energy level, capture time and emission time, activation energies for capture and emission, and trap location in the gate dielectric, were determined. The configuration coordinate diagram was also established. It was observed that the implanted Al could fill defects and form a thin Al{sub 2}O{sub 3} layer and thus increase the tunneling barrier height for holes. It was also observed that the trap position in the Al I/I samples was lower due to the Al I/I-induced dipole at the HfO{sub 2}/SiO{sub 2} interface.

  3. Air-moving device noise: An overview

    Science.gov (United States)

    Maling, George C., Jr.

    This paper presents a review of published information on the noise emission of small blowers and fans. The design is given for a noise meter for air-movement devices. The summary of research on noise sources and noise reduction includes information on axial-flow fans and centrifugal blowers. Sound reduction methods discussed include the introduction of obstructions and dampening plates and grilles. References are given for information on environmetal effects of fan noise. Design criteria and scaling laws are presented for minimal noise production. The paper identifies issues where further research is needed.

  4. SLMRACE: a noise-free RACE implementation with reduced computational time

    Science.gov (United States)

    Chauvin, Juliet; Provenzi, Edoardo

    2017-05-01

    We present a faster and noise-free implementation of the RACE algorithm. RACE has mixed characteristics between the famous Retinex model of Land and McCann and the automatic color equalization (ACE) color-correction algorithm. The original random spray-based RACE implementation suffers from two main problems: its computational time and the presence of noise. Here, we will show that it is possible to adapt two techniques recently proposed by Banić et al. to the RACE framework in order to drastically decrease the computational time and noise generation. The implementation will be called smart-light-memory-RACE (SLMRACE).

  5. Noise management of industrial parks

    Energy Technology Data Exchange (ETDEWEB)

    Senden, Virgini [HFP Acoustical Consultants Corp (Canada)], email: virgini.senden@hfpacoustical.com

    2011-07-01

    Because of industrial development, more noise-producing facilities are being built, with negative noise impacts on local residents' lives and comfort. The question raised by this paper is which way would be the best to ensure both acceptable noise impact, and efficient industrial facilities operations? The author presents two approaches: the {sup r}egional noise management plan{sup ,} adopted in Alberta, leaves the different industries present in the region in charge of noise emissions, working both together and individually to maintain acceptable noise pollution levels. The zoned industrial parks approach, in effect in the Netherlands, where industrial parks are situated within a noise zone, outside of which noise impact should be reduced to levels that do not disturb residents. Both approaches are effective, but demand a great deal of effort to achieve noise efficiency. The Alberta approach, thanks to its specificity and the collaborative work of all actors involved, facilitates continuous improvement while the Dutch approach is more rigid, but better suited to industry realities and the space that is available in the Netherlands.

  6. Evaluation of a new syringe presentation of reduced-antigen content diphtheria, tetanus, and acellular pertussis vaccine in healthy adolescents--A single blind randomized trial.

    Science.gov (United States)

    Pavia-Ruz, Noris; Abarca, Katia; Lepetic, Alejandro; Cervantes-Apolinar, Maria Yolanda; Hardt, Karin; Jayadeva, Girish; Kuriyakose, Sherine; Han, Htay Htay; de la O, Manuel

    2015-01-01

    Reduced-antigen-content diphtheria-tetanus-acellular pertussis (dTpa) vaccine, Boostrix™, is indicated for booster vaccination of children, adolescents and adults. The original prefilled disposable dTpa syringe presentation was recently replaced by another prefilled-syringe presentation with latex-free tip-caps and plunger-stoppers. 671 healthy adolescents aged 10-15 years who had previously received 5 or 6 previous DT(P)/dT(pa) vaccine doses, were randomized (1:1) to receive dTpa booster, injected using the new (dTpa-new) or previous syringe (dTpa-previous) presentations. Immunogenicity was assessed before and 1-month post-booster vaccination; safety/reactogenicity were assessed during 31-days post-vaccination. Non-inferiority of dTpa-new versus dTpa-previous was demonstrated for all antigens (ULs 95% CIs for GMC ratios ranged between 1.03-1.13). 1-month post-booster, immune responses were in similar ranges for all antigens with both syringe presentations. dTpa delivered using either syringe presentation was well-tolerated. These clinical results complement the technical data and support the use of the new syringe presentation to deliver the dTpa vaccine.

  7. Fast High-Quality Noise

    DEFF Research Database (Denmark)

    Frisvad, Jeppe Revall; Wyvill, Geoff

    2007-01-01

    At the moment the noise functions available in a graphics programmer's toolbox are either slow to compute or they involve grid-line artifacts making them of lower quality. In this paper we present a real-time noise computation with no grid-line artifacts or other regularity problems. In other wor...

  8. Noise in Optical Amplifiers

    DEFF Research Database (Denmark)

    Jeppesen, Palle

    1997-01-01

    Noise in optical amplifiers is discussed on the basis of photons and electromagntic fields. Formulas for quantum noise from spontaneous emission, signal-spontaneous beat noise and spontaneous-spontaneous beat noise are derived.......Noise in optical amplifiers is discussed on the basis of photons and electromagntic fields. Formulas for quantum noise from spontaneous emission, signal-spontaneous beat noise and spontaneous-spontaneous beat noise are derived....

  9. Low noise road surfaces

    OpenAIRE

    Bolčina, Matjaž

    2014-01-01

    Noise is everywhere. Noise is a sound that makes people stressful and irritate. It often couses sleep disorders and also health problems like different cardiovascular disorders, hearing loss…In most cases traffic noise is the most disturbing. There are different ways to prevent people from traffic noise like building noise barriers and insulation of facades. However noise barriers and insulation of facades do not prevent noise formation, but are lowering existing noise. Another disadvantage i...

  10. Pixel electronic noise as a function of position in an active matrix flat panel imaging array

    Science.gov (United States)

    Yazdandoost, Mohammad Y.; Wu, Dali; Karim, Karim S.

    2010-04-01

    We present an analysis of output referred pixel electronic noise as a function of position in the active matrix array for both active and passive pixel architectures. Three different noise sources for Active Pixel Sensor (APS) arrays are considered: readout period noise, reset period noise and leakage current noise of the reset TFT during readout. For the state-of-the-art Passive Pixel Sensor (PPS) array, the readout noise of the TFT switch is considered. Measured noise results are obtained by modeling the array connections with RC ladders on a small in-house fabricated prototype. The results indicate that the pixels in the rows located in the middle part of the array have less random electronic noise at the output of the off-panel charge amplifier compared to the ones in rows at the two edges of the array. These results can help optimize for clearer images as well as help define the region-of-interest with the best signal-to-noise ratio in an active matrix digital flat panel imaging array.

  11. A Robust Recursive Filter for Nonlinear Systems with Correlated Noises, Packet Losses, and Multiplicative Noises

    Directory of Open Access Journals (Sweden)

    Hua-Ming Qian

    2014-01-01

    Full Text Available A robust filtering problem is formulated and investigated for a class of nonlinear systems with correlated noises, packet losses, and multiplicative noises. The packet losses are assumed to be independent Bernoulli random variables. The multiplicative noises are described as random variables with bounded variance. Different from the traditional robust filter based on the assumption that the process noises are uncorrelated with the measurement noises, the objective of the addressed robust filtering problem is to design a recursive filter such that, for packet losses and multiplicative noises, the state prediction and filtering covariance matrices have the optimized upper bounds in the case that there are correlated process and measurement noises. Two examples are used to illustrate the effectiveness of the proposed filter.

  12. Mismatch negativity (MMN) in high and low noise sensitive individuals

    NARCIS (Netherlands)

    White, Kim; Meeter, Martijn

    2015-01-01

    Although noise sensitivity is known to be an important determinant of noise annoyance, its neural underpinnings are not yet well established. In the present study, high and low noise sensitive participants were selected based on their scores on the Noise Sensitivity Scale (NSS) and the Noise

  13. Noise variance estimation for Kalman filter

    Science.gov (United States)

    Beniak, Ryszard; Gudzenko, Oleksandr; Pyka, Tomasz

    2017-10-01

    In this paper, we propose an algorithm that evaluates noise variance with a numerical integration method. For noise variance estimation, we use Krogh method with a variable integration step. In line with common practice, we limit our study to fourth-order method. First, we perform simulation tests for randomly generated signals, related to the transition state and steady state. Next, we formulate three methodologies (research hypotheses) of noise variance estimation, and then compare their efficiency.

  14. Noise in time-discrete analog filters

    Science.gov (United States)

    Kroemer, B.; Mueller, R.; Stegherr, M.; Klar, H.; Ulbrich, W.

    The most important noise sources in time-discrete analog filters which can be monolithically integrated as CCD and switched-capacitor structures are described. In CCD filters, these sources are thermal kTC noise of the input and output levels and unloading processes at the surface attraction sites. Attainable signal-to-noise ratios and optimization possibilities are stated. For SC filters, the most important noise sources are kTC noise and l/f noise. On-chip clock jitter noise can be suppressed by differential processing. The present measurements on integrated MOS switching transistors with small areas confirm the thermal kTC noise limit and show that there is no additional l/f contribution to the noise from the switches. For the integrator, good agreement is obtained between theory and experiment when an operational amplifier with finite unity-gain frequency is included.

  15. Noise mapping inside a car cabin

    DEFF Research Database (Denmark)

    Knudsen, Kim; Sjøj, Sidsel Marie Nørholm; Jacobsen, Finn

    The mapping of noise is of considerable interest in the car industry where a good noise mapping can make it much easier to identify the sources that generate the noise and eventually reduce the individual contributions to the noise. The methods used for this purpose include delay-and-sum beamform......The mapping of noise is of considerable interest in the car industry where a good noise mapping can make it much easier to identify the sources that generate the noise and eventually reduce the individual contributions to the noise. The methods used for this purpose include delay......-and-sum beamforming and spherical harmonics beamforming. These methods have a poor spatial esolution at low frequencies, and since much noise generated in cars is dominated by low frequencies the methods are not optimal. In the present paper the mapping is done by solving an inverse problem with a transfer matrix...

  16. The effect of alternative graphical displays used to present the benefits of antibiotics for sore throat on decisions about whether to seek treatment: a randomized trial.

    Directory of Open Access Journals (Sweden)

    Cheryl L L Carling

    2009-08-01

    Full Text Available BACKGROUND: We conducted an Internet-based randomized trial comparing four graphical displays of the benefits of antibiotics for people with sore throat who must decide whether to go to the doctor to seek treatment. Our objective was to determine which display resulted in choices most consistent with participants' values. METHODS AND FINDINGS: This was the first of a series of televised trials undertaken in cooperation with the Norwegian Broadcasting Company. We recruited adult volunteers in Norway through a nationally televised weekly health program. Participants went to our Web site and rated the relative importance of the consequences of treatment using visual analogue scales (VAS. They viewed the graphical display (or no information to which they were randomized and were asked to decide whether to go to the doctor for an antibiotic prescription. We compared four presentations: face icons (happy/sad or a bar graph showing the proportion of people with symptoms on day three with and without treatment, a bar graph of the average duration of symptoms, and a bar graph of proportion with symptoms on both days three and seven. Before completing the study, all participants were shown all the displays and detailed patient information about the treatment of sore throat and were asked to decide again. We calculated a relative importance score (RIS by subtracting the VAS scores for the undesirable consequences of antibiotics from the VAS score for the benefit of symptom relief. We used logistic regression to determine the association between participants' RIS and their choice. 1,760 participants completed the study. There were statistically significant differences in the likelihood of choosing to go to the doctor in relation to different values (RIS. Of the four presentations, the bar graph of duration of symptoms resulted in decisions that were most consistent with the more fully informed second decision. Most participants also preferred this

  17. Investigation of Noises in GPS Time Series: Case Study on Epn Weekly Solutions

    Science.gov (United States)

    Klos, Anna; Bogusz, Janusz; Figurski, Mariusz; Kosek, Wieslaw; Gruszczynski, Maciej

    2014-05-01

    The noises in GPS time series are stated to be described the best by the combination of white (Gaussian) and power-law processes. They are mainly the effect of mismodelled satellite orbits, Earth orientation parameters, atmospheric effects, antennae phase centre effects, or of monument instability. Due to the fact, that velocities of permanent stations define the kinematic reference frame, they have to fulfil the requirement of being stable at 0.1 mm/yr. The previously performed researches showed, that the wrong assumption of noise model leads to the underestimation of velocities and their uncertainties from 2 up to even 11, especially in the Up direction. This presentation focuses on more than 200 EPN (EUREF Permanent Network) stations from the area of Europe with various monument types (concrete pillars, buildings, metal masts, with or without domes, placed on the ground or on the rock) and coordinates of weekly changes (GPS weeks 0834-1459). The topocentric components (North, East, Up) in ITRF2005 which come from the EPN Re-Processing made by the Military University of Technology Local Analysis Centre (MUT LAC) were processed with Maximum Likelihood Estimation (MLE) using CATS software. We have assumed the existence of few combinations of noise models (these are: white, flicker and random walk noise with integer spectral indices and power-law noise models with fractional spectral indices) and investigated which of them EPN weekly time series are likely to follow. The results show, that noises in GPS time series are described the best by the combination of white and flicker noise model. It is strictly related to the so-called common mode error (CME) that is spatially correlated error being one of the dominant error source in GPS solutions. We have assumed CME as spatially uniform, what was a good approximation for stations located hundreds of kilometres one to another. Its removal with spatial filtering reduces the amplitudes of white and flicker noise by a

  18. Shaping the spectrum of random-phase radar waveforms

    Science.gov (United States)

    Doerry, Armin W.; Marquette, Brandeis

    2017-05-09

    The various technologies presented herein relate to generation of a desired waveform profile in the form of a spectrum of apparently random noise (e.g., white noise or colored noise), but with precise spectral characteristics. Hence, a waveform profile that could be readily determined (e.g., by a spoofing system) is effectively obscured. Obscuration is achieved by dividing the waveform into a series of chips, each with an assigned frequency, wherein the sequence of chips are subsequently randomized. Randomization can be a function of the application of a key to the chip sequence. During processing of the echo pulse, a copy of the randomized transmitted pulse is recovered or regenerated against which the received echo is correlated. Hence, with the echo energy range-compressed in this manner, it is possible to generate a radar image with precise impulse response.

  19. Several rotor noise sources and treatments

    Energy Technology Data Exchange (ETDEWEB)

    Tangler, J. [National Renewable Energy Laboratory, Golden, CO (United States)

    1997-12-31

    Noise has been a design consideration in the development of advanced blades and turbines at the National Renewable Energy Laboratory. During atmospheric testing associated with these efforts various types of aeroacoustic noise have been encountered. This presentation discusses several of these noise sources and treatments used to mitigate or eliminate the noise. Tonal noise resulting from tip-vortex/trailing-edge interaction and laminar separation bubbles was found to be easily eliminated. Impulsive noise resulting from blade/vortex interaction for rotors that furl and that due to tower shadow can be mitigated by various means. (au)

  20. An Improved Semisoft Threshold Algorithm and Its Evaluation for Denoising Random Walk in GNSS Time Series

    Directory of Open Access Journals (Sweden)

    WU Hao

    2017-05-01

    Full Text Available The differences in the satellite orbit and signal quality of global navigation satellite positioning system, resulting in the complexity of random walk noise in GNSS time series, has become a bottleneck problem in applying GNSS technology to the high precision deformation monitoring industry. For the complex characteristics of random walk noise, small magnitude, low frequency and low sensitivity, an improved semisoft threshold algorithm is presented. Then it forms a unified system of semisoft threshold function, so as to improve the adaptability of conventional semisoft threshold for random walk noise. In order to verify and evaluate the effect of improved semisoft threshold algorithm, MATLAB platform is used to generate a linear trend, periodic and random walk noise of the GNSS time series, a total of 1700 epochs. The results show that the improved semisoft threshold method is better than the classical method, and has better performance in the SNR and root mean square error. The evaluation results show that the morphological character has been performanced high consistency between the noise reduced by improved method with random walk noise. Further from the view of quantitative point, the evaluation results of spectral index analysis verify the applicability of the improved method for random walk noise.

  1. An analysis of noise in recurrent neural networks: convergence and generalization.

    Science.gov (United States)

    Jim, K C; Giles, C L; Horne, B G

    1996-01-01

    Concerns the effect of noise on the performance of feedforward neural nets. We introduce and analyze various methods of injecting synaptic noise into dynamically driven recurrent nets during training. Theoretical results show that applying a controlled amount of noise during training may improve convergence and generalization performance. We analyze the effects of various noise parameters and predict that best overall performance can be achieved by injecting additive noise at each time step. Noise contributes a second-order gradient term to the error function which can be viewed as an anticipatory agent to aid convergence. This term appears to find promising regions of weight space in the beginning stages of training when the training error is large and should improve convergence on error surfaces with local minima. The first-order term is a regularization term that can improve generalization. Specifically, it can encourage internal representations where the state nodes operate in the saturated regions of the sigmoid discriminant function. While this effect can improve performance on automata inference problems with binary inputs and target outputs, it is unclear what effect it will have on other types of problems. To substantiate these predictions, we present simulations on learning the dual parity grammar from temporal strings for all noise models, and present simulations on learning a randomly generated six-state grammar using the predicted best noise model.

  2. Effectiveness of a mentor-implemented, violence prevention intervention for assault-injured youths presenting to the emergency department: results of a randomized trial.

    Science.gov (United States)

    Cheng, Tina L; Haynie, Denise; Brenner, Ruth; Wright, Joseph L; Chung, Shang-en; Simons-Morton, Bruce

    2008-11-01

    The goal was to assess the impact of a mentor-implemented, violence prevention intervention in reducing aggression, fighting, and reinjury among assault-injured youths. In a randomized, controlled trial performed in the emergency departments of 2 large urban hospitals, 10- to 15-year-old youths who presented with peer assault injuries were recruited and randomly assigned to intervention and comparison groups. In the intervention group, youths received a mentor, who implemented a 6-session problem-solving curriculum, and parents received 3 home visits with a health educator, to discuss family needs and to facilitate service use and parental monitoring. The comparison group received a list of community resources, with 2 follow-up telephone calls to facilitate service use. Youths and parents were interviewed at baseline and at 6 months, for assessment of attitudes about violence, risk factors, fighting, and repeat injury. A total of 227 families were recruited, with 23% refusing participation and 4% providing partial interview completion. A total of 166 families were enrolled, with 87 assigned to the intervention group and 79 to the comparison group; 118 (71%) completed both youth and parent follow-up interviews, and 113 had usable data. The intervention and comparison groups were not significantly different at baseline with respect to demographic features or risk factors, except for increased knife-carrying and fewer deviant peers in the intervention group. After adjustment for baseline differences, there was a trend toward significant program effects, including reduced misdemeanor activity and youth-reported aggression scores and increased youth self-efficacy. Program impact was associated with the number of intervention sessions received. A community-based, mentor-implemented program with assault-injured youths who presented to the emergency department trended in the direction of decreased violence, with reduced misdemeanors and increased self-efficacy.

  3. Effectiveness of a Mentor-Implemented Violence Prevention Intervention for Assault-Injured Youth Presenting to the Emergency Department: Results of a Randomized Trial

    Science.gov (United States)

    Cheng, Tina L.; Haynie, Denise; Brenner, Ruth; Wright, Joseph L.; Chung, Shang-en; Simons-Morton, Bruce

    2008-01-01

    Context The emergency department has been described as a promising setting to initiate interventions with assault-injured youth to reduce the risk of re-injury and reactive perpetration. Efforts to intervene have received little study. Objective To assess the impact of a mentor-implemented violence prevention intervention on reducing aggression, fighting and re-injury among assault-injured youth. Design Randomized controlled trial Setting Two large urban hospital emergency departments Participants Youth age 10–15 presenting with peer assault injury were recruited and randomly assigned to intervention and comparison groups. Intervention Intervention youth received a mentor who implemented a 6 session problem-solving curriculum while parents received 3 home visits with a health educator to discuss family needs and facilitate service use and parental monitoring. The comparison group received a list of community resources with 2 follow-up phone calls to facilitate service use. Main Outcome Measures Youth and parents were interviewed at baseline and 6 months to assess attitudes about violence, risk factors, fighting and repeat injury. Results 227 families were recruited with 23% refusing participation and 4% partial interview completion. 166 families were enrolled with 87 randomized to the intervention group and 79 in the comparison group; 118 (71%) completed both youth and parent follow-up interviews and 113 had usable data. Intervention and comparison groups were not significantly different at baseline on demographics or risk factors except for increased knife carrying and less deviant peers in the intervention group. After adjustment for baseline differences, there was a trend toward significant program effect including reducing misdemeanor activity (rate ratio 0.29, confidence interval 0.08–0.98), youth-reported aggression scores (rate ratio .63, 0.4–1.00) and increasing youth self efficacy (beta=2.28, p<.05). Program impact was associated with number of

  4. Ultrawideband Noise Radar Imaging of Impenetrable Cylindrical Objects Using Diffraction Tomography

    Directory of Open Access Journals (Sweden)

    Hee Jung Shin

    2014-01-01

    Full Text Available Ultrawideband (UWB waveforms achieve excellent spatial resolution for better characterization of targets in tomographic imaging applications compared to narrowband waveforms. In this paper, two-dimensional tomographic images of multiple scattering objects are successfully obtained using the diffraction tomography approach by transmitting multiple independent and identically distributed (iid UWB random noise waveforms. The feasibility of using a random noise waveform for tomography is investigated by formulating a white Gaussian noise (WGN model using spectral estimation. The analytical formulation of object image formation using random noise waveforms is established based on the backward scattering, and several numerical diffraction tomography simulations are performed in the spatial frequency domain to validate the analytical results by reconstructing the tomographic images of scattering objects. The final image of the object based on multiple transmitted noise waveforms is reconstructed by averaging individually formed images which compares very well with the image created using the traditional Gaussian pulse. Pixel difference-based measure is used to analyze and estimate the image quality of the final reconstructed tomographic image under various signal-to-noise ratio (SNR conditions. Also, preliminary experiment setup and measurement results are presented to assess the validation of simulation results.

  5. Aircraft and background noise annoyance effects

    Science.gov (United States)

    Willshire, K. F.

    1984-01-01

    To investigate annoyance of multiple noise sources, two experiments were conducted. The first experiment, which used 48 subjects, was designed to establish annoyance-noise level functions for three community noise sources presented individually: jet aircraft flyovers, air conditioner, and traffic. The second experiment, which used 216 subjects, investigated the effects of background noise on aircraft annoyance as a function of noise level and spectrum shape; and the differences between overall, aircraft, and background noise annoyance. In both experiments, rated annoyance was the dependent measure. Results indicate that the slope of the linear relationship between annoyance and noise level for traffic is significantly different from that of flyover and air conditioner noise and that further research was justified to determine the influence of the two background noises on overall, aircraft, and background noise annoyance (e.g., experiment two). In experiment two, total noise exposure, signal-to-noise ratio, and background source type were found to have effects on all three types of annoyance. Thus, both signal-to-noise ratio, and the background source must be considered when trying to determine community response to combined noise sources.

  6. Background Noise Reduction Using Adaptive Noise Cancellation Determined by the Cross-Correlation

    Science.gov (United States)

    Spalt, Taylor B.; Brooks, Thomas F.; Fuller, Christopher R.

    2012-01-01

    Background noise due to flow in wind tunnels contaminates desired data by decreasing the Signal-to-Noise Ratio. The use of Adaptive Noise Cancellation to remove background noise at measurement microphones is compromised when the reference sensor measures both background and desired noise. The technique proposed modifies the classical processing configuration based on the cross-correlation between the reference and primary microphone. Background noise attenuation is achieved using a cross-correlation sample width that encompasses only the background noise and a matched delay for the adaptive processing. A present limitation of the method is that a minimum time delay between the background noise and desired signal must exist in order for the correlated parts of the desired signal to be separated from the background noise in the crosscorrelation. A simulation yields primary signal recovery which can be predicted from the coherence of the background noise between the channels. Results are compared with two existing methods.

  7. Complexity in White Noise Analysis

    Science.gov (United States)

    Hida, Takeyuki

    We restrict our attention to random complex systems and discuss degree their degree of complexity based on a white noise. The white noise is realized as the time derivative of a Brownian motion B(t), and denoted by Ḃ(t). The collection {Ḃ(t)}, is a system of idealized elementary variables and at the same time the system is a stochastic representation of the time t, in other words it is time-oriented. Having expressed the given evolutional random phenomena in question in terms of the Ḃ(t), we introduce the notion of spectral multiplicity, which describes how much the phenomena are complex. The multiplicity is the number of cyclic subspaces that are spanned by the given random phenomena. Each cyclic subspace has further structure. Typical property is multiple Markov property, although this property appears only particular cases. As a related property, in fact as a characteristic of a complex system, one can speak of the time reversibility and irreversibility of certain random phenomena in terms of the white noise. We expect an irreversible random complex system may be decomposed into reversible systems.

  8. Estimating the coherence of noise

    Science.gov (United States)

    Wallman, Joel

    To harness the advantages of quantum information processing, quantum systems have to be controlled to within some maximum threshold error. Certifying whether the error is below the threshold is possible by performing full quantum process tomography, however, quantum process tomography is inefficient in the number of qubits and is sensitive to state-preparation and measurement errors (SPAM). Randomized benchmarking has been developed as an efficient method for estimating the average infidelity of noise to the identity. However, the worst-case error, as quantified by the diamond distance from the identity, can be more relevant to determining whether an experimental implementation is at the threshold for fault-tolerant quantum computation. The best possible bound on the worst-case error (without further assumptions on the noise) scales as the square root of the infidelity and can be orders of magnitude greater than the reported average error. We define a new quantification of the coherence of a general noise channel, the unitarity, and show that it can be estimated using an efficient protocol that is robust to SPAM. Furthermore, we also show how the unitarity can be used with the infidelity obtained from randomized benchmarking to obtain improved estimates of the diamond distance and to efficiently determine whether experimental noise is close to stochastic Pauli noise.

  9. Phase noise in RF and microwave amplifiers.

    Science.gov (United States)

    Boudot, Rodolphe; Rubiola, Enrico

    2012-12-01

    Understanding amplifier phase noise is a critical issue in many fields of engineering and physics, such as oscillators, frequency synthesis, telecommunication, radar, and spectroscopy; in the emerging domain of microwave photonics; and in exotic fields, such as radio astronomy, particle accelerators, etc. Focusing on the two main types of base noise in amplifiers, white and flicker, the power spectral density of the random phase φ(t) is Sφ(f) = b(0) + b(-1)/f. White phase noise results from adding white noise to the RF spectrum in the carrier region. For a given RF noise level, b(0) is proportional to the reciprocal of the carrier power P(0). By contrast, flicker results from a near-dc 1/f noise-present in all electronic devices-which modulates the carrier through some parametric effect in the semiconductor. Thus, b(-1) is a parameter of the amplifier, constant in a wide range of P(0). The consequences are the following: Connecting m equal amplifiers in parallel, b(-1) is 1/m times that of one device. Cascading m equal amplifiers, b(-1) is m times that of one amplifier. Recirculating the signal in an amplifier so that the gain increases by a power of m (a factor of m in decibels) as a result of positive feedback (regeneration), we find that b(-1) is m(2) times that of the amplifier alone. The feedforward amplifier exhibits extremely low b(-1) because the carrier is ideally nulled at the input of its internal error amplifier. Starting with an extensive review of the literature, this article introduces a system-oriented model which describes the phase flickering. Several amplifier architectures (cascaded, parallel, etc.) are analyzed systematically, deriving the phase noise from the general model. There follow numerous measurements of amplifiers using different technologies, including some old samples, and in a wide frequency range (HF to microwaves), which validate the theory. In turn, theory and results provide design guidelines and give suggestions for CAD and

  10. Noise Analysis of Switched-Current Circuits

    DEFF Research Database (Denmark)

    Jørgensen, Ivan Harald Holger; Bogason, Gudmundur

    1998-01-01

    The understanding of noise in analog sampled data systems is vital for the design of high resolution circuitry. In this paper a general description of sampled and held noise is presented. The noise calculations are verified by measurements on an analog delay line implemented using switched...

  11. Sampled Noise in Switched Current Circuits

    DEFF Research Database (Denmark)

    Jørgensen, Ivan Herald Holger; Bogason, Gudmundur

    1997-01-01

    The understanding of noise in analog sampled data systems is vital for the design of high resolution circuitry. In this paper a general description of sampled and held noise is presented. The noise calculations are verified by measurements on an analog delay line implemented using switched...

  12. Effectiveness of individualized physiotherapy on pain and functioning compared to a standard exercise protocol in patients presenting with clinical signs of subacromial impingement syndrome. A randomized controlled trial.

    Science.gov (United States)

    Kromer, Thilo O; de Bie, Rob A; Bastiaenen, Caroline H G

    2010-06-09

    Shoulder impingement syndrome is a common musculoskeletal complaint leading to significant reduction of health and disability. Physiotherapy is often the first choice of treatment although its effectiveness is still under debate. Systematic reviews in this field highlight the need for more high quality trials to investigate the effectiveness of physiotherapy interventions in patients with subacromial impingement syndrome. This randomized controlled trial will investigate the effectiveness of individualized physiotherapy in patients presenting with clinical signs and symptoms of subacromial impingement, involving 90 participants aged 18-75. Participants are recruited from outpatient physiotherapy clinics, general practitioners, and orthopaedic surgeons in Germany. Eligible participants will be randomly allocated to either individualized physiotherapy or to a standard exercise protocol using central randomization. The control group will perform the standard exercise protocol aiming to restore muscular deficits in strength, mobility, and coordination of the rotator cuff and the shoulder girdle muscles to unload the subacromial space during active movements. Participants of the intervention group will perform the standard exercise protocol as a home program, and will additionally be treated with individualized physiotherapy based on clinical examination results, and guided by a decision tree. After the intervention phase both groups will continue their home program for another 7 weeks. Outcome will be measured at 5 weeks and at 3 and 12 months after inclusion using the shoulder pain and disability index and patients' global impression of change, the generic patient-specific scale, the average weekly pain score, and patient satisfaction with treatment. Additionally, the fear avoidance beliefs questionnaire, the pain catastrophizing scale, and patients' expectancies of treatment effect are assessed. Participants' adherence to the protocol, use of additional treatments

  13. Effectiveness of individualized physiotherapy on pain and functioning compared to a standard exercise protocol in patients presenting with clinical signs of subacromial impingement syndrome. A randomized controlled trial

    Directory of Open Access Journals (Sweden)

    de Bie Rob A

    2010-06-01

    Full Text Available Abstract Background Shoulder impingement syndrome is a common musculoskeletal complaint leading to significant reduction of health and disability. Physiotherapy is often the first choice of treatment although its effectiveness is still under debate. Systematic reviews in this field highlight the need for more high quality trials to investigate the effectiveness of physiotherapy interventions in patients with subacromial impingement syndrome. Methods/Design This randomized controlled trial will investigate the effectiveness of individualized physiotherapy in patients presenting with clinical signs and symptoms of subacromial impingement, involving 90 participants aged 18-75. Participants are recruited from outpatient physiotherapy clinics, general practitioners, and orthopaedic surgeons in Germany. Eligible participants will be randomly allocated to either individualized physiotherapy or to a standard exercise protocol using central randomization. The control group will perform the standard exercise protocol aiming to restore muscular deficits in strength, mobility, and coordination of the rotator cuff and the shoulder girdle muscles to unload the subacromial space during active movements. Participants of the intervention group will perform the standard exercise protocol as a home program, and will additionally be treated with individualized physiotherapy based on clinical examination results, and guided by a decision tree. After the intervention phase both groups will continue their home program for another 7 weeks. Outcome will be measured at 5 weeks and at 3 and 12 months after inclusion using the shoulder pain and disability index and patients' global impression of change, the generic patient-specific scale, the average weekly pain score, and patient satisfaction with treatment. Additionally, the fear avoidance beliefs questionnaire, the pain catastrophizing scale, and patients' expectancies of treatment effect are assessed. Participants

  14. Underwater radiated noise from modern commercial ships.

    Science.gov (United States)

    McKenna, Megan F; Ross, Donald; Wiggins, Sean M; Hildebrand, John A

    2012-01-01

    Underwater radiated noise measurements for seven types of modern commercial ships during normal operating conditions are presented. Calibrated acoustic data (Stern aspect noise levels are 5 to 10 dB higher than bow aspect noise levels. Collectively, these results emphasize the importance of including modern ship-types in quantifying shipping noise for predictive models of global, regional, and local marine environments. © 2012 Acoustical Society of America.

  15. Curing the noise epidemic

    Science.gov (United States)

    Mazer, Susan

    2005-09-01

    The argument is made that design does not stop when the fixed architectural and acoustical components are in place. Spaces live and breathe with the people who reside in them. Research and examples are presented that show that noise, auditory clutter, thrives on itself in hospitals. Application of the Lombard reflex studies fit into the hospital setting, but do not offer solutions as to how one might reduce the impact. In addition, the basis for looking at the noise component as a physical as well cultural dynamic will be addressed. Whether the result of the wrong conversation in the wrong place or the right conversation in an unfortunate place, talk mixed with sounds of technology is shown to cause its own symptoms. From heightened anxiety and stress to medical errors, staff burnout, or HIPAA violations, the case is made that noise is pandemic in hospitals and demands financial and operational investment. An explanation of how to reduce noise by design of the dynamic environment - equipment, technology, staff protocols is also provided.

  16. Wind turbine noise diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Richarz, W. [Aerocoustics Engineering Ltd., Toronto, ON (Canada); Richarz, H.

    2009-07-01

    This presentation proposed a self-consistent model for broad-band noise emitted from modern wind turbines. The simple source model was consistent with the physics of sound generation and considered the unique features of wind turbines. Although the acoustics of wind turbines are similar to those of conventional propellers, the dimensions of wind turbines pose unique challenges in diagnosing noise emission. The general features of the sound field were deduced. Source motion and source directivity appear to be responsible for amplitude variations. The amplitude modulation is likely to make wind-turbine noise more audible, and may be partly responsible for annoyance that has been reported in the literature. Acoustic array data suggests that broad-band noise is emitted predominantly during the downward sweep of each rotor blade. Source motion and source directivity account for the observed pattern. Rotor-tower interaction effects are of lesser importance. Predicted amplitude modulation ranges from 1 dB to 6dB. 2 refs., 9 figs.

  17. Using potential performance theory to analyze systematic and random factors in enumeration tasks.

    Science.gov (United States)

    Hunt, Gayle; Rice, Stephen; Trafimow, David; Sandry, Joshua

    2013-01-01

    Prior research has shown that as the number of items being enumerated increases, performance decreases, especially when the amount of time is limited. Researchers studying nonverbal enumeration have found that random noise increases as a function of the number of items presented. Over a series of 2 experiments, the authors used potential performance theory to expand these findings and discover precisely how much random noise actually influences observed performance and what performance might look like in the absence of random factors. Participants briefly viewed a visual stimulus comprising a set of 4 to 9 dots presented horizontally (Experiment 1) or randomly (Experiment 2) on a computer monitor. Findings from both experiments indicate that the decrease in performance for larger set sizes resulted almost entirely from a reduction in consistency (or an increase in random noise), whereas potential performance remained fairly constant until the maximum set size.

  18. Detection of signals in noise

    CERN Document Server

    Whalen, Anthony D; Declaris, Nicholas

    1971-01-01

    Detection of Signals in Noise serves as an introduction to the principles and applications of the statistical theory of signal detection. The book discusses probability and random processes; narrowband signals, their complex representation, and their properties described with the aid of the Hilbert transform; and Gaussian-derived processes. The text also describes the application of hypothesis testing for the detection of signals and the fundamentals required for statistical detection of signals in noise. Problem exercises, references, and a supplementary bibliography are included after each c

  19. SiGe HBT Nonlinear Phase Noise Modeling - X-band amplifier design

    OpenAIRE

    Gribaldo, Sébastien; Bary, Laurent; Llopis, Olivier

    2008-01-01

    International audience; A nonlinear noise model of a SiGe bipolar transistor is presented. This model includes a nonlinear noise source and is able to predict the noise conversion phenomena in circuits using this transistor such as oscillator phase noise. It is based on two main low frequency noise sources, which are extracted thanks to noise measurements under large RF signal superposition. An original low phase noise X band amplifier is also presented. This amplifier features a phase noise ...

  20. Trajectories of Brownian particles with space-correlated noise

    Indian Academy of Sciences (India)

    The Langevin equation used to model Brownian motion includes a stochastic process that is routinely assumed to be a Gaussian white noise. Spatial correlations of the noise are usually ruled out, and the paths traced by the random walkers are statistically independent. In this study, I consider instead noise which is white in ...

  1. Gain Dependence of the Noise in the Single Electron Transistor

    OpenAIRE

    Starmark, B.; Henning, Torsten; Korotkov, A. N.; Claeson, T.; Delsing, P.

    1998-01-01

    An extensive investigation of low frequency noise in single electron transistors as a function of gain is presented. Comparing the output noise with gain for a large number of bias points, it is found that the noise is dominated by external charge noise. For low gains we find an additional noise contribution which is compared to a model including resistance fluctuations. We conclude that this excess noise is not only due to resistance fluctuations. For one sample, we find a record low minimum...

  2. Road-Traffic Noise: Annoyance, Risk Perception, and Noise Sensitivity in the Finnish Adult Population

    Directory of Open Access Journals (Sweden)

    Enembe Oku Okokon

    2015-05-01

    Full Text Available Exposure to road-traffic noise commonly engenders annoyance, the extent of which is determined by factors not fully understood. Our aim was to estimate the prevalence and determinants of road-traffic noise annoyance and noise sensitivity in the Finnish adult population, while comparing the perceptions of road-traffic noise to exhausts as environmental health problems. Using a questionnaire that yielded responses from 1112 randomly selected adult Finnish respondents, we estimated road-traffic noise- and exhausts-related perceived exposures, health-risk perceptions, and self-reported annoyance on five-point scales, while noise sensitivity estimates were based on four questions. Determinants of noise annoyance and sensitivity were investigated using multivariate binary logistic regression and linear regression models, respectively. High or extreme noise annoyance was reported by 17% of respondents. Noise sensitivity scores approximated a Gaussian distribution. Road-traffic noise and exhausts were, respectively, considered high or extreme population-health risks by 22% and 27% of respondents. Knowledge of health risks from traffic noise, OR: 2.04 (1.09–3.82 and noise sensitivity, OR: 1.07 (1.00–1.14 were positively associated with annoyance. Knowledge of health risks (p < 0.045 and positive environmental attitudes (p < 000 were associated with higher noise sensitivity. Age and sex were associated with annoyance and sensitivity only in bivariate models. A considerable proportion of Finnish adults are highly annoyed by road-traffic noise, and perceive it to be a significant health risk, almost comparable to traffic exhausts. There is no distinct noise-sensitive population subgroup. Knowledge of health risks of road-traffic noise, and attitudinal variables are associated with noise annoyance and sensitivity.

  3. Road-Traffic Noise: Annoyance, Risk Perception, and Noise Sensitivity in the Finnish Adult Population

    Science.gov (United States)

    Okokon, Enembe Oku; Turunen, Anu W.; Ung-Lanki, Sari; Vartiainen, Anna-Kaisa; Tiittanen, Pekka; Lanki, Timo

    2015-01-01

    Exposure to road-traffic noise commonly engenders annoyance, the extent of which is determined by factors not fully understood. Our aim was to estimate the prevalence and determinants of road-traffic noise annoyance and noise sensitivity in the Finnish adult population, while comparing the perceptions of road-traffic noise to exhausts as environmental health problems. Using a questionnaire that yielded responses from 1112 randomly selected adult Finnish respondents, we estimated road-traffic noise- and exhausts-related perceived exposures, health-risk perceptions, and self-reported annoyance on five-point scales, while noise sensitivity estimates were based on four questions. Determinants of noise annoyance and sensitivity were investigated using multivariate binary logistic regression and linear regression models, respectively. High or extreme noise annoyance was reported by 17% of respondents. Noise sensitivity scores approximated a Gaussian distribution. Road-traffic noise and exhausts were, respectively, considered high or extreme population-health risks by 22% and 27% of respondents. Knowledge of health risks from traffic noise, OR: 2.04 (1.09–3.82) and noise sensitivity, OR: 1.07 (1.00–1.14) were positively associated with annoyance. Knowledge of health risks (p noise sensitivity. Age and sex were associated with annoyance and sensitivity only in bivariate models. A considerable proportion of Finnish adults are highly annoyed by road-traffic noise, and perceive it to be a significant health risk, almost comparable to traffic exhausts. There is no distinct noise-sensitive population subgroup. Knowledge of health risks of road-traffic noise, and attitudinal variables are associated with noise annoyance and sensitivity. PMID:26016432

  4. Predetermining acceptable noise limits in EXAFS spectra in the limit of stochastic noise

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Yung-Jin; Booth, Corwin H

    2009-12-14

    EXAFS measurements are used to probe a variety of experimental systems, but excel at elucidating local structure in samples which have slight disorder or no long-range crystalline order. Of special interest to the authors is the use of EXAFS in understanding the molecular-level binding structure and characteristics of actinides on the surface of environmental minerals and model mineral analogs. In environmental systems the element of interest can be on the order of 10-7% by weight of the total sample. Obviously such samples would be impossible to measure using EXAFS techniques. It is therefore essential to increase the concentration of the element of interest while still preserving a sample's ability to represent environmental conditions. Under such low concentration limits it is expected that the collected data is countrate, or stochastically limited. This condition occurs as we approach the signal-to-noise (S/N) limit of the technique where the random noise of the measurement process dominates over possible systematic errors. When stochastic error is expected to dominate systematic error, it is possible to predict, with the use of simulations, the ability of model fits to tolerate a certain level of stochastic noise. Elsewhere in these proceedings, we discuss how to tell when systematic errors dominate in measured EXAFS spectrum. Here, we outline a technique for determining the number of EXAFS scans necessary to test the relevance of a given structural model. Appropriate stochastic noise levels are determined for each point in r-space by collecting data on a real system. These noise levels are then applied to EXAFS simulations using a test model. In this way, all significant systematic error sources are eliminated in the simulated data. The structural model is then fit to the simulated data, decreasing the noise and increasing the k-range of the fit until the veracity of the model passes an F-test. This paper outlines a method of testing model systems in

  5. External noise distinguishes attention mechanisms.

    Science.gov (United States)

    Lu, Z L; Dosher, B A

    1998-05-01

    We developed and tested a powerful method for identifying and characterizing the effect of attention on performance in visual tasks as due to signal enhancement, distractor exclusion, or internal noise suppression. Based on a noisy Perceptual Template Model (PTM) of a human observer, the method adds increasing amounts of external noise (white gaussian random noise) to the visual stimulus and observes the effect on performance of a perceptual task for attended and unattended stimuli. The three mechanisms of attention yield three "signature" patterns of performance. The general framework for characterizing the mechanisms of attention is used here to investigate the attentional mechanisms in a concurrent location-cued orientation discrimination task. Test stimuli--Gabor patches tilted slightly to the right or left--always appeared on both the left and the right of fixation, and varied independently. Observers were cued on each trial to attend to the left, the right, or evenly to both stimuli, and decide the direction of tilt of both test stimuli. For eight levels of added external noise and three attention conditions (attended, unattended, and equal), subjects' contrast threshold levels were determined. At low levels of external noise, attention affected threshold contrast: threshold contrasts for non-attended stimuli were systematically higher than for equal attention stimuli, which were, in turn, higher than for attended stimuli. Specifically, when the rms contrast of the external noise is below 10%, there is a consistent 17% elevation of contrast threshold from attended to unattended condition across all three subjects. For higher levels of external noise, attention conditions did not affect threshold contrast values at all. These strong results are characteristic of a signal enhancement, or equivalently, an internal additive noise reduction mechanism of attention.

  6. Probabilistic solutions of nonlinear oscillators excited by combined colored and white noise excitations

    Science.gov (United States)

    Siu-Siu, Guo; Qingxuan, Shi

    2017-03-01

    In this paper, single-degree-of-freedom (SDOF) systems combined to Gaussian white noise and Gaussian/non-Gaussian colored noise excitations are investigated. By expressing colored noise excitation as a second-order filtered white noise process and introducing colored noise as an additional state variable, the equation of motion for SDOF system under colored noise is then transferred artificially to multi-degree-of-freedom (MDOF) system under white noise excitations with four-coupled first-order differential equations. As a consequence, corresponding Fokker-Planck-Kolmogorov (FPK) equation governing the joint probabilistic density function (PDF) of state variables increases to 4-dimension (4-D). Solution procedure and computer programme become much more sophisticated. The exponential-polynomial closure (EPC) method, widely applied for cases of SDOF systems under white noise excitations, is developed and improved for cases of systems under colored noise excitations and for solving the complex 4-D FPK equation. On the other hand, Monte Carlo simulation (MCS) method is performed to test the approximate EPC solutions. Two examples associated with Gaussian and non-Gaussian colored noise excitations are considered. Corresponding band-limited power spectral densities (PSDs) for colored noise excitations are separately given. Numerical studies show that the developed EPC method provides relatively accurate estimates of the stationary probabilistic solutions, especially the ones in the tail regions of the PDFs. Moreover, statistical parameter of mean-up crossing rate (MCR) is taken into account, which is important for reliability and failure analysis. Hopefully, our present work could provide insights into the investigation of structures under random loadings.

  7. Inhibitory noise

    Directory of Open Access Journals (Sweden)

    Alain Destexhe

    2010-03-01

    Full Text Available Cortical neurons in vivo may operate in high-conductance states, in which the major part of the neuron's input conductance is due to synaptic activity, sometimes several-fold larger than the resting conductance. We examine here the contribution of inhibition in such high-conductance states. At the level of the absolute conductance values, several studies have shown that cortical neurons in vivo are characterized by strong inhibitory conductances. However, conductances are balanced and spiking activity is mostly determined by fluctuations, but not much is known about excitatory and inhibitory contributions to these fluctuations. Models and dynamic-clamp experiments show that, during high-conductance states, spikes are mainly determined by fluctuations of inhibition, or by inhibitory noise. This stands in contrast to low-conductance states, in which excitatory conductances determine spiking activity. To determine these contributions from experimental data, maximum likelihood methods can be designed and applied to intracellular recordings in vivo. Such methods indicate that action potentials are indeed mostly correlated with inhibitory fluctuations in awake animals. These results argue for a determinant role for inhibitory fluctuations in evoking spikes, and do not support feed-forward modes of processing, for which opposite patterns are predicted.

  8. Using noise to shape motor learning.

    Science.gov (United States)

    Thorp, Elias B; Kording, Konrad P; Mussa-Ivaldi, Ferdinando A

    2017-02-01

    Each of our movements is selected from any number of alternative movements. Some studies have shown evidence that the central nervous system (CNS) chooses to make the specific movements that are least affected by motor noise. Previous results showing that the CNS has a natural tendency to minimize the effects of noise make the direct prediction that if the relationship between movements and noise were to change, the specific movements people learn to make would also change in a predictable manner. Indeed, this has been shown for well-practiced movements such as reaching. Here, we artificially manipulated the relationship between movements and visuomotor noise by adding noise to a motor task in a novel redundant geometry such that there arose a single control policy that minimized the noise. This allowed us to see whether, for a novel motor task, people could learn the specific control policy that minimized noise or would need to employ other compensation strategies to overcome the added noise. As predicted, subjects were able to learn movements that were biased toward the specific ones that minimized the noise, suggesting not only that the CNS can learn to minimize the effects of noise in a novel motor task but also that artificial visuomotor noise can be a useful tool for teaching people to make specific movements. Using noise as a teaching signal promises to be useful for rehabilitative therapies and movement training with human-machine interfaces. Many theories argue that we choose to make the specific movements that minimize motor noise. Here, by changing the relationship between movements and noise, we show that people actively learn to make movements that minimize noise. This not only provides direct evidence for the theories of noise minimization but presents a way to use noise to teach specific movements to improve rehabilitative therapies and human-machine interface control. Copyright © 2017 the American Physiological Society.

  9. Innovative speckle noise reduction procedure in optical encryption

    Science.gov (United States)

    Vélez Zea, Alejandro; Fredy Barrera, John; Torroba, Roberto

    2017-05-01

    Encrypting techniques are currently of interest in the optical domain. A common issue when using coherent techniques is speckle noise which influences the final results. Most efforts to solve this issue were directed towards processing the output of the systems. Instead, we present an alternative approach where we seek to control the input to enhance the performance of these techniques. In particular, we analyze an encoding procedure with a joint transform correlator architecture as a case study. We first demonstrate the dependence of the output noise on the spatial distribution of the input, showing the existence of a neglected random correlation noise which contributes to the degradation of the output. We then propose a rearrangement of the input that results in a reduction of the noise level in the outcome. This rearrangement consists of separating the pixels of the input by introducing black pixels between them, keeping the usual remaining procedure unaltered. Our experimental approach opens up new possibilities for the applications of optical security techniques beyond the limitations imposed by noise.

  10. Noise-Measuring Method

    DEFF Research Database (Denmark)

    Diamond, J. M.

    1965-01-01

    A noise-measuring method based on the use of a calibrated noise generator and an output meter with a special scale is described. The method eliminates the effect of noise contributions occurring in the circuits following the device under test.......A noise-measuring method based on the use of a calibrated noise generator and an output meter with a special scale is described. The method eliminates the effect of noise contributions occurring in the circuits following the device under test....

  11. Model of aircraft noise adaptation

    Science.gov (United States)

    Dempsey, T. K.; Coates, G. D.; Cawthorn, J. M.

    1977-01-01

    Development of an aircraft noise adaptation model, which would account for much of the variability in the responses of subjects participating in human response to noise experiments, was studied. A description of the model development is presented. The principal concept of the model, was the determination of an aircraft adaptation level which represents an annoyance calibration for each individual. Results showed a direct correlation between noise level of the stimuli and annoyance reactions. Attitude-personality variables were found to account for varying annoyance judgements.

  12. Harmonic and attosecond pulse enhancement in the presence of noise

    Science.gov (United States)

    Feng, Li-Qiang; Chu, Tian-Shu

    2012-12-01

    In this paper, we theoretically investigate the effect of noise on the photoionization, the generation of the high-order harmonic and the attosecond pulse irradiated from a model He+ ion. It shows that by properly adding noise fields, such as Gaussian white noise, random light or colored noise, both the ionization probabilities (IPs) and the harmonic yields can be enhanced by several orders of magnitude. Further, by tuning the noise intensity, a stochastic resonance-like curve is observed, showing the existence of an optimal noise in the ionization enhancement process. Finally, by superposing a properly selected harmonic, an intense attosecond pulse with a duration of 67 as is directly generated.

  13. Uncorrelated Noise in Turbulence Measurements

    DEFF Research Database (Denmark)

    Kristensen, Leif; Lenschow, D. H.

    1985-01-01

    of atmospheric variability. The authors assume that the measured signal is a representation of a variable that is continuous on the scale of interest in the atmosphere. Uncorrelated noise affects the autovariance function (or, equivalently, the structure function) only between zero and the first lag, while its......We show that the error variance contributed by random uncorrelated measurement noise can be merged with the error variance contributed by real variation in the atmosphere to obtain a single expression for the total error variance when the sampling time is much less than the integral scale...... effect is smeared across the entire power spectrum. For this reason, quantities such as variance dissipation may be more conveniently estimated from the structure function than from the spectrum. The modeling results are confirmed by artificially modifying a test time series with Poisson noise...

  14. Food2Learn: Randomized control trial investigating influence of krill oil supplementation on learning, cognition, and behaviour in healthy adolescents. Design presentation

    NARCIS (Netherlands)

    Van der Wurff, Inge; Von Schacky, Clemens; Berge, Kjetil; Kirschner, Paul A.; De Groot, Renate

    2014-01-01

    Food2Learn is a double blind randomized controlled trial which looks at the influence of Krill oil (rich in LCPUFA) on the cognitive performance, academic performance and mental well-being of student of lower vocational schools.

  15. Graph-analytic method of approximate calculation of the levels and contours of noise from aircraft

    Directory of Open Access Journals (Sweden)

    О.І. Запорожець

    2007-03-01

    Full Text Available  The paper presents substantiation of methodologies for evaluation of aircraft noise levels and noise countures using their acoustical characteristics approved in the certificate of aircraft type. The graphic analytical method of noise levels and noise contures is analysed. The comparison of certified noise levels and noise levels calculated for EPNL criteria is done using INM software.

  16. Physical measures of sound and noise

    Science.gov (United States)

    1984-01-01

    The physical measurement of sound is examined through basic definitions and measuring techniques. The terminology of acoustics is presented with noise characterization, graphs, and mathematical formulas included.

  17. Destruction of noise in biotelemetry.

    Science.gov (United States)

    Fraden, J

    1979-01-01

    The difference in statistical characteristics between physiological signals and noise creates the possibility of designing a selective circuit to separate signals from noise. Analysis shows that by an extremely low signal-to-noise ratio before the pulse conditioner in a biotelemetry system, the mixture of normal and spurious pulses are present at the demodulator input. The system of noise destruction analyzes the sequential distances between two following pulses and blanks all spurious pulses using the criteria of high autocorrelation of physiological signals in short intervals. Evaluation of the circuit demonstrates a dramatic increase in accuracy in the presence of strong interference because the system of noise destruction performs a linear extrapolation of free-of-noise parts of pulse flow into destroyed spaces. The equations to calculate selective thresholds and output errors are delineated. The noise destructor is especially useful in long-term monitoring and automatic data analysis because it prevents a formation of sharp noisy spikes at the biotelemetry system's output.

  18. Signal-to-noise considerations for sky-subtracted CCD data

    Science.gov (United States)

    Newberry, Michael V.

    1991-01-01

    The standard equation for calculating the uncertainty of photometry obtained from CCDs does not correctly consider the random errors, or 'noise', introduced into observations by procedures used in reducing the data. This paper presents a thorough derivation of the theoretical error equation that considers the contributions from all internal noise sources in the signal-to-noise ratio (S/N) of a sky-subtracted image. A simplified version used for estimating the internal errors from empirical data is also derived. The propagation of noise through the data-reduction process is illustrated through a series of equations for the change in S/N that results from a variety of different operations performed on a CCD frame. Comparing these effects with the results expected for an observation made with an ideal detector suggests a number of ways to improve the precision of photometry through the practices employed in obtaining and reducing the observations.

  19. The effect of extrinsic noise on the dynamics of simple gene network motifs

    Science.gov (United States)

    Assaf, Michael

    Cellular processes do not follow deterministic rules; even in identical environments genetically identical cells can make random choices leading to different phenotypes. This randomness originates from fluctuations present in the biomolecular interaction networks. Most previous work has been focused on the intrinsic noise of these networks. Yet, especially for high-copy-number biomolecules, extrinsic or environmental noise has been experimentally shown to dominate the variation. Here we develop an analytical formalism that allows for calculation of the combined effect of intrinsic and extrinsic noise on gene expression motifs. We introduce a new and generic method for modeling bounded extrinsic noise as an auxiliary species in the master equation. We focus our study on motifs that can be viewed as the building blocks of genetic switches: a non-regulated gene, a self-inhibiting gene, and a self-promoting gene. The role of the extrinsic noise properties (magnitude, correlation time, and distribution) on the statistics of interest are systematically investigated, and the effect of fluctuations in different reaction rates is compared. Due to its analytical nature, our formalism can be used to quantify the effect of extrinsic noise on the dynamics of biochemical networks and can also be used to improve the interpretation of data from single-cell gene expression experiments.

  20. Aircraft en route noise annoyance

    Science.gov (United States)

    Mccurdy, David A.

    1990-01-01

    Results are reported from a laboratory experiment conducted in order to quantify the annoyance experienced by people on the ground in response to en route noise (ERN) generated by aircraft at cruise conditions. Objectives included the comparison of annoyance responses to ERN with the annoyance responses to takeoff and landing noise; the comparison of the annoyance responses to advanced turboprop aircraft ERN with those of the turbofan ERN; and also the ability of aircraft noise measurement procedures and corrections to predict annoyance to ERN. Tests were conducted at the Langley Acoustics Research Laboratory on 32 human subjects selected at random. Subjects judged the annoyance level of 24 Propfan Test Assessment advanced turboprop ERN stimuli, 18 conventional turbofan ERN stimuli, and 60 conventional turboprop and turbofan takeoff and landing noise stimuli. Analysis of resulting data compared annoyance responses to different aircraft types and operations, examined the ability of current noise measurement and correction procedures to predict annoyance ERN, and calculated optimum duration correction magnitudes for ERN.

  1. Hearing through the noise: Biologically inspired noise reduction

    Science.gov (United States)

    Lee, Tyler Paul

    Vocal communication in the natural world demands that a listener perform a remarkably complicated task in real-time. Vocalizations mix with all other sounds in the environment as they travel to the listener, arriving as a jumbled low-dimensional signal. A listener must then use this signal to extract the structure corresponding to individual sound sources. How this computation is implemented in the brain remains poorly understood, yet an accurate description of such mechanisms would impact a variety of medical and technological applications of sound processing. In this thesis, I describe initial work on how neurons in the secondary auditory cortex of the Zebra Finch extract song from naturalistic background noise. I then build on our understanding of the function of these neurons by creating an algorithm that extracts speech from natural background noise using spectrotemporal modulations. The algorithm, implemented as an artificial neural network, can be flexibly applied to any class of signal or noise and performs better than an optimal frequency-based noise reduction algorithm for a variety of background noises and signal-to-noise ratios. One potential drawback to using spectrotemporal modulations for noise reduction, though, is that analyzing the modulations present in an ongoing sound requires a latency set by the slowest temporal modulation computed. The algorithm avoids this problem by reducing noise predictively, taking advantage of the large amount of temporal structure present in natural sounds. This predictive denoising has ties to recent work suggesting that the auditory system uses attention to focus on predicted regions of spectrotemporal space when performing auditory scene analysis.

  2. White noise theory of robust nonlinear filtering with correlated state and observation noises

    NARCIS (Netherlands)

    Bagchi, Arunabha; Karandikar, Rajeeva

    1992-01-01

    In the direct white noise theory of nonlinear filtering, the state process is still modeled as a Markov process satisfying an Ito stochastic differential equation, while a finitely additive white noise is used to model the observation noise. In the present work, this asymmetry is removed by modeling

  3. Binaural Integrated Active Noise Control and Noise Reduction in Hearing Aids

    DEFF Research Database (Denmark)

    Serizel, Romain; Moonen, Marc; Wouters, Jan

    2013-01-01

    This paper presents a binaural approach to integrated active noise control and noise reduction in hearing aids and aims at demonstrating that a binaural setup indeed provides significant advantages in terms of the number of noise sources that can be compensated for and in terms of the causality...

  4. Effect of Prolonged Exposure Therapy Delivered Over 2 Weeks vs 8 Weeks vs Present-Centered Therapy on PTSD Symptom Severity in Military Personnel: A Randomized Clinical Trial.

    Science.gov (United States)

    Foa, Edna B; McLean, Carmen P; Zang, Yinyin; Rosenfield, David; Yadin, Elna; Yarvis, Jeffrey S; Mintz, Jim; Young-McCaughan, Stacey; Borah, Elisa V; Dondanville, Katherine A; Fina, Brooke A; Hall-Clark, Brittany N; Lichner, Tracey; Litz, Brett T; Roache, John; Wright, Edward C; Peterson, Alan L

    2018-01-23

    Effective and efficient treatment is needed for posttraumatic stress disorder (PTSD) in active duty military personnel. To examine the effects of massed prolonged exposure therapy (massed therapy), spaced prolonged exposure therapy (spaced therapy), present-centered therapy (PCT), and a minimal-contact control (MCC) on PTSD severity. Randomized clinical trial conducted at Fort Hood, Texas, from January 2011 through July 2016 and enrolling 370 military personnel with PTSD who had returned from Iraq, Afghanistan, or both. Final follow-up was July 11, 2016. Prolonged exposure therapy, cognitive behavioral therapy involving exposure to trauma memories/reminders, administered as massed therapy (n = 110; 10 sessions over 2 weeks) or spaced therapy (n = 109; 10 sessions over 8 weeks); PCT, a non-trauma-focused therapy involving identifying/discussing daily stressors (n = 107; 10 sessions over 8 weeks); or MCC, telephone calls from therapists (n = 40; once weekly for 4 weeks). Outcomes were assessed before and after treatment and at 2-week, 12-week, and 6-month follow-up. Primary outcome was interviewer-assessed PTSD symptom severity, measured by the PTSD Symptom Scale-Interview (PSS-I; range, 0-51; higher scores indicate greater PTSD severity; MCID, 3.18), used to assess efficacy of massed therapy at 2 weeks posttreatment vs MCC at week 4; noninferiority of massed therapy vs spaced therapy at 2 weeks and 12 weeks posttreatment (noninferiority margin, 50% [2.3 points on PSS-I, with 1-sided α = .05]); and efficacy of spaced therapy vs PCT at posttreatment. Among 370 randomized participants, data were analyzed for 366 (mean age, 32.7 [SD, 7.3] years; 44 women [12.0%]; mean baseline PSS-I score, 25.49 [6.36]), and 216 (59.0%) completed the study. At 2 weeks posttreatment, mean PSS-I score was 17.62 (mean decrease from baseline, 7.13) for massed therapy and 21.41 (mean decrease, 3.43) for MCC (difference in decrease, 3.70 [95% CI,0.72 to 6.68]; P = .02

  5. Non-Markovian noise

    Energy Technology Data Exchange (ETDEWEB)

    Fulinski, A. (Institute of Physics, Jagellonian University, Reymonta 4, PL-30-059 Krakow (Poland))

    1994-10-01

    The properties of non-Markovian noises with exponentially correlated memory are discussed. Considered are dichotomic noise, white shot noise, Gaussian white noise, and Gaussian colored noise. The stationary correlation functions of the non-Markovian versions of these noises are given by linear combinations of two or three exponential functions (colored noises) or of the [delta] function and exponential function (white noises). The non-Markovian white noises are well defined only when the kernel of the non-Markovian master equation contains a nonzero admixture of a Markovian term. Approximate equations governing the probability densities for processes driven by such non-Markovian noises are derived, including non-Markovian versions of the Fokker-Planck equation and the telegrapher's equation. As an example, it is shown how the non-Markovian nature changes the behavior of the driven linear process.

  6. Noise measurements on Si sensors

    CERN Document Server

    Peisert, Anna; Kokkas, P; Manthos, N; Prouskas, C; Triantis, F A; Tzoulis, N; Aspell, P; Barney, D; Bloch, P; Kloukinas, K; Reynaud, S; Go, A; Elsha, V; Zubarev, E

    2002-01-01

    Developing silicon strip sensors for the CMS Preshower detector we have noticed that some strips have a noise higher than the average and not correlated to a high leakage current. In order to investigate this effect we have developed a set-up for noise measurement on wafers and diced sensors that does not require bonding. The set-up is based on the DeltaStream chip coupled to a probe card. We have tested 45 sensors and found that the strips with an above average noise have a higher relative current increase as a function of voltage, DeltaI /(IDeltaV). We also observed that, on these strips, the breakdown occurs within about 60 V from the voltage at which the noise is observed. We describe our measurement method and present the results.

  7. assessment of noise pollutio noise pollutio noise pollution

    African Journals Online (AJOL)

    eobe

    This study examine. This study examined noise pollution pollution pollution from sawmillin from sawmillin using HD600 digital data l using HD600 digital data logging sound level me ogging sound level me designed to elicit noise related information. The res sawmills was 58.1 sawmills was 58.1-64.86 dB(A) while machine ...

  8. assessment of noise pollutio noise pollutio noise pollution

    African Journals Online (AJOL)

    eobe

    related ailments such as tinnitus (96.6%), headache (86.6%) se prevention and control strategies are suggested in additio. , education, and enforcement of noise regulations. , education, and enforcement of noise regulations. machine, workers, impacts. , particularly at global concern as strong some high-ranking health.

  9. On the attenuation and amplification of molecular noise in genetic regulatory networks

    Directory of Open Access Journals (Sweden)

    Wang Yu-Chao

    2006-02-01

    Full Text Available Abstract Background Noise has many important roles in cellular genetic regulatory functions at the nanomolar scale. At present, no good theory exists for identifying all possible mechanisms of genetic regulatory networks to attenuate the molecular noise to achieve regulatory ability or to amplify the molecular noise to randomize outcomes to the advantage of diversity. Therefore, the noise filtering of genetic regulatory network is an important topic for gene networks under intrinsic fluctuation and extrinsic noise. Results Based on stochastic dynamic regulation equation, the intrinsic fluctuation in reaction rates is modeled as a state-dependent stochastic process, which will influence the stability of gene regulatory network, especially, with low concentrations of reacting species. Then the mechanisms of genetic regulatory network to attenuate or amplify extrinsic fluctuation are revealed from the nonlinear stochastic filtering point of view. Furthermore, a simple measure of attenuation level or amplification level of extrinsic noise for genetic regulatory networks is also introduced by nonlinear robust filtering method. Based on the global linearization scheme, a convenient method is introduced to measure noise attenuation or amplification for each gene of the nonlinear stochastic regulatory network by solving a set of filtering problems, which correspond to a set of linearized stochastic regulatory networks. Finally, by the proposed methods, several simulation examples of genetic regulatory networks are given to measure their robust stability under intrinsic fluctuations, and to estimate the genes' attenuation and amplification levels under extrinsic noises. Conclusion In this study, a stochastic nonlinear dynamic model is developed for genetic regulatory networks under intrinsic fluctuation and extrinsic noise. By the method we proposed, we could determine the robust stability under intrinsic fluctuations and identify the genes that are

  10. Aircraft engine noise

    Science.gov (United States)

    Kennepohl, F.

    An overview of the main aircraft engine noise sources is given. Special emphasis is devoted to turbomachinery/rotor noise, which plays an important role in all engine concepts appropriate to regional aircraft, such as turbofans, propellers, or new propfan engine concepts. The noise generating mechanisms, including propagation within the engine, and calculation methods used are described. Noise reduction methods are considered, with emphasis on cutoff design of turbomachines. Some noise features of counter rotating propellers and swept rotor blades are mentioned.

  11. Amperometric noise at thin film band electrodes.

    Science.gov (United States)

    Larsen, Simon T; Heien, Michael L; Taboryski, Rafael

    2012-09-18

    Background current noise is often a significant limitation when using constant-potential amperometry for biosensor application such as amperometric recordings of transmitter release from single cells through exocytosis. In this paper, we fabricated thin-film electrodes of gold and conductive polymers and measured the current noise in physiological buffer solution for a wide range of different electrode areas. The noise measurements could be modeled by an analytical expression, representing the electrochemical cell as a resistor and capacitor in series. The studies revealed three domains; for electrodes with low capacitance, the amplifier noise dominated, for electrodes with large capacitances, the noise from the resistance of the electrochemical cell was dominant, while in the intermediate region, the current noise scaled with electrode capacitance. The experimental results and the model presented here can be used for choosing an electrode material and dimensions and when designing chip-based devices for low-noise current measurements.

  12. The impact of crowd noise on officiating in muay thai: achieving external validity in an experimental setting.

    Science.gov (United States)

    Myers, Tony; Balmer, Nigel

    2012-01-01

    Numerous factors have been proposed to explain the home advantage in sport. Several authors have suggested that a partisan home crowd enhances home advantage and that this is at least in part a consequence of their influence on officiating. However, while experimental studies examining this phenomenon have high levels of internal validity (since only the "crowd noise" intervention is allowed to vary), they suffer from a lack of external validity, with decision-making in a laboratory setting typically bearing little resemblance to decision-making in live sports settings. Conversely, observational and quasi-experimental studies with high levels of external validity suffer from low levels of internal validity as countless factors besides crowd noise vary. The present study provides a unique opportunity to address these criticisms, by conducting a controlled experiment on the impact of crowd noise on officiating in a live tournament setting. Seventeen qualified judges officiated on thirty Thai boxing bouts in a live international tournament setting featuring "home" and "away" boxers. In each bout, judges were randomized into a "noise" (live sound) or "no crowd noise" (noise-canceling headphones and white noise) condition, resulting in 59 judgments in the "no crowd noise" and 61 in the "crowd noise" condition. The results provide the first experimental evidence of the impact of live crowd noise on officials in sport. A cross-classified statistical model indicated that crowd noise had a statistically significant impact, equating to just over half a point per bout (in the context of five round bouts with the "10-point must" scoring system shared with professional boxing). The practical significance of the findings, their implications for officiating and for the future conduct of crowd noise studies are discussed.

  13. Secure Image Encryption Based On a Chua Chaotic Noise Generator

    Directory of Open Access Journals (Sweden)

    A. S. Andreatos

    2013-10-01

    Full Text Available This paper presents a secure image cryptography telecom system based on a Chua's circuit chaotic noise generator. A chaotic system based on synchronised Master–Slave Chua's circuits has been used as a chaotic true random number generator (CTRNG. Chaotic systems present unpredictable and complex behaviour. This characteristic, together with the dependence on the initial conditions as well as the tolerance of the circuit components, make CTRNGs ideal for cryptography. In the proposed system, the transmitter mixes an input image with chaotic noise produced by a CTRNG. Using thresholding techniques, the chaotic signal is converted to a true random bit sequence. The receiver must be able to reproduce exactly the same chaotic noise in order to subtract it from the received signal. This becomes possible with synchronisation between the two Chua's circuits: through the use of specific techniques, the trajectory of the Slave chaotic system can be bound to that of the Master circuit producing (almost identical behaviour. Additional blocks have been used in order to make the system highly parameterisable and robust against common attacks. The whole system is simulated in Matlab. Simulation results demonstrate satisfactory performance, as well as, robustness against cryptanalysis. The system works with both greyscale and colour jpg images.

  14. Noise slows the rate of Michaelis-Menten reactions.

    Science.gov (United States)

    Van Dyken, J David

    2017-10-07

    Microscopic randomness and the small volumes of living cells combine to generate random fluctuations in molecule concentrations called "noise". Here I investigate the effect of noise on biochemical reactions obeying Michaelis-Menten kinetics, concluding that substrate noise causes these reactions to slow. I derive a general expression for the time evolution of the joint probability density of chemical species in arbitrarily connected networks of non-linear chemical reactions in small volumes. This equation is a generalization of the chemical master equation (CME), a common tool for investigating stochastic chemical kinetics, extended to reaction networks occurring in small volumes, such as living cells. I apply this equation to a generalized Michaelis-Menten reaction in an open system, deriving the following general result: 〈p〉≤p¯ and 〈s〉≥s¯, where s¯ and p¯ denote the deterministic steady-state concentration of reactant and product species, respectively, and 〈s〉 and 〈p〉 denote the steady-state ensemble average over independent realizations of a stochastic reaction. Under biologically realistic conditions, namely when substrate is degraded or diluted by cell division, 〈p〉≤p¯. Consequently, noise slows the rate of in vivo Michaelis-Menten reactions. These predictions are validated by extensive stochastic simulations using Gillespie's exact stochastic simulation algorithm. I specify the conditions under which these effects occur and when they vanish, therefore reconciling discrepancies among previous theoretical investigations of stochastic biochemical reactions. Stochastic slowdown of reaction flux caused by molecular noise in living cells may have functional consequences, which the present theory may be used to quantify. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Equilibrium and shot noise in mesoscopic systems

    Energy Technology Data Exchange (ETDEWEB)

    Martin, T.

    1994-10-01

    Within the last decade, there has been a resurgence of interest in the study of noise in Mesoscopic devices, both experimentally and theoretically. Noise in solid state devices can have different origins: there is 1/f noise, which is believed to arise from fluctuations in the resistance of the sample due to the motion of impurities. On top of this contribution is a frequency independent component associated with the stochastic nature of electron transport, which will be the focus of this paper. If the sample considered is small enough that dephasing and inelastic effects can be neglected, equilibrium (thermal) and excess noise can be completely described in terms of the elastic scattering properties of the sample. As mentioned above, noise arises as a consequence of random processes governing the transport of electrons. Here, there are two sources of randomness: first, electrons incident on the sample occupy a given energy state with a probability given by the Fermi-Dirac distribution function. Secondly, electrons can be transmitted across the sample or reflected in the same reservoir where they came from with a probability given by the quantum mechanical transmission/reflection coefficients. Equilibrium noise refers to the case where no bias voltage is applied between the leads connected to the sample, where thermal agitation alone allows the electrons close to the Fermi level to tunnel through the sample. In general, equilibrium noise is related to the conductance of the sample via the Johnson-Nyquist formula. In the presence of a bias, in the classical regime, one expects to recover the full shot noise < {Delta}{sup 2}I >= 2I{Delta}{mu} as was observed a long time ago in vacuum diodes. In the Mesoscopic regime, however, excess noise is reduced below the shot noise level. The author introduces a more intuitive picture, where the current passing through the device is a superposition of pulses, or electron wave packets, which can be transmitted or reflected.

  16. Indirect combustion noise of auxiliary power units

    Science.gov (United States)

    Tam, Christopher K. W.; Parrish, Sarah A.; Xu, Jun; Schuster, Bill

    2013-08-01

    Recent advances in noise suppression technology have significantly reduced jet and fan noise from commercial jet engines. This leads many investigators in the aeroacoustics community to suggest that core noise could well be the next aircraft noise barrier. Core noise consists of turbine noise and combustion noise. There is direct combustion noise generated by the combustion processes, and there is indirect combustion noise generated by the passage of combustion hot spots, or entropy waves, through constrictions in an engine. The present work focuses on indirect combustion noise. Indirect combustion noise has now been found in laboratory experiments. The primary objective of this work is to investigate whether indirect combustion noise is also generated in jet and other engines. In a jet engine, there are numerous noise sources. This makes the identification of indirect combustion noise a formidable task. Here, our effort concentrates exclusively on auxiliary power units (APUs). This choice is motivated by the fact that APUs are relatively simple engines with only a few noise sources. It is, therefore, expected that the chance of success is higher. Accordingly, a theoretical model study of the generation of indirect combustion noise in an Auxiliary Power Unit (APU) is carried out. The cross-sectional areas of an APU from the combustor to the turbine exit are scaled off to form an equivalent nozzle. A principal function of a turbine in an APU is to extract mechanical energy from the flow stream through the exertion of a resistive force. Therefore, the turbine is modeled by adding a negative body force to the momentum equation. This model is used to predict the ranges of frequencies over which there is a high probability for indirect combustion noise generation. Experimental spectra of internal pressure fluctuations and far-field noise of an RE220 APU are examined to identify anomalous peaks. These peaks are possible indirection combustion noise. In the case of the

  17. Adaptive EMG noise reduction in ECG signals using noise level approximation

    Science.gov (United States)

    Marouf, Mohamed; Saranovac, Lazar

    2017-12-01

    In this paper the usage of noise level approximation for adaptive Electromyogram (EMG) noise reduction in the Electrocardiogram (ECG) signals is introduced. To achieve the adequate adaptiveness, a translation-invariant noise level approximation is employed. The approximation is done in the form of a guiding signal extracted as an estimation of the signal quality vs. EMG noise. The noise reduction framework is based on a bank of low pass filters. So, the adaptive noise reduction is achieved by selecting the appropriate filter with respect to the guiding signal aiming to obtain the best trade-off between the signal distortion caused by filtering and the signal readability. For the evaluation purposes; both real EMG and artificial noises are used. The tested ECG signals are from the MIT-BIH Arrhythmia Database Directory, while both real and artificial records of EMG noise are added and used in the evaluation process. Firstly, comparison with state of the art methods is conducted to verify the performance of the proposed approach in terms of noise cancellation while preserving the QRS complex waves. Additionally, the signal to noise ratio improvement after the adaptive noise reduction is computed and presented for the proposed method. Finally, the impact of adaptive noise reduction method on QRS complexes detection was studied. The tested signals are delineated using a state of the art method, and the QRS detection improvement for different SNR is presented.

  18. Noise hazard course

    CERN Multimedia

    2003-01-01

    A 1/2 day course to promote awareness of the risks incurred by noise at the work place and recommendations to settle them. Next course Wednesday 24th September 2003. Costs are covered by TIS, Jacques Coillard from Bureau Véritas will present the course. Registration is obligatory. For more information and to enrol on this course go to the safety section of Human Resources Training and Development web pages, or contact : Ana-Paula Bernardes/TIS-GS (71385) or e-mail Ana-Paula.Bernardes@cern.ch

  19. Noise hazard course

    CERN Multimedia

    2003-01-01

    A 1/2 day course to promote awareness of the risks incurred by noise at the work place and recommendations to settle them. Next course Wednesday 24th September 2003. Costs are covered by TIS, Jacques Coillard from Bureau Véritas will present the course. Registration is obligatory. For more information and to enrol on this course go to the safety section of Human Resources Training and Development web pages, or contact: Ana-Paula Bernardes/TIS-GS (71385) or e-mail Ana-Paula.Bernardes@cern.ch

  20. Noise reduction by wavelet thresholding

    National Research Council Canada - National Science Library

    Jansen, Maarten

    2001-01-01

    .... I rather present new material and own insights in the que stions involved with wavelet based noise reduction . On the other hand , the presented material does cover a whole range of methodologies, and in that sense, the book may serve as an introduction into the domain of wavelet smoothing. Throughout the text, three main properties show up ever again: spar...

  1. Noise limitations in optical linear algebra processors.

    Science.gov (United States)

    Batsell, S G; Jong, T L; Walkup, J F; Krile, T F

    1990-05-10

    A general statistical noise model is presented for optical linear algebra processors. A statistical analysis which includes device noise, the multiplication process, and the addition operation is undertaken. We focus on those processes which are architecturally independent. Finally, experimental results which verify the analytical predictions are also presented.

  2. Application of GIS in Urban Traffic Noise Pollution

    OpenAIRE

    Manouchehr Omidvari; Ali Asghar Alesheikh

    2010-01-01

    Large urban areas are facing growing problems of noise pollutions. Geospatial Information Systems (GIS) can conveniently be adapted to gather, analyze and present noise information. GIS can also be extended to answer to user specific problems through deterministic and statistics models. The objectives of this research were to measure urban traffic noise levels, analyze temporal and spatial dynamics of urban traffic-induced noise pollution in the first districted of Tehran estimate the noise f...

  3. Evaluation Of Noise Cancellation Using LMS And NLMS Algorithm

    OpenAIRE

    Niti Gupta; Dr. Poonam Bansal

    2015-01-01

    This paper is focused on the adaptive noise cancellation of speech signal using the least mean square LMS and normalized least mean square method NLMS. Adaptive Noise Cancellation is an alternative way of cancelling noise present in a corrupted signal. In this technique evaluation of distorted signal by additive noise or interference achieved with no a priori estimates of signal or noise. A comparative study is carried out using LMS and NLSM methods. Result shows that these methods has potent...

  4. Influence of core stability exercise on lumbar vertebral instability in patients presented with chronic low back pain: A randomized clinical trial

    OpenAIRE

    Javadian, Yahya; Akbari, Mohammad; Talebi, Ghoadamali; Taghipour-Darzi, Mohammad; Janmohammadi, Naser

    2015-01-01

    Background: Excessive lumbar vertebrae translation and rotation in sagittal plane has been attributed as an associated factor of lumbar segmental instability (LSI) and low back pain (LBP). Reduction of these abnormalities improves back pain. The aim of this study was to investigate the effect of core stability exercise on the translation and rotation of lumbar vertebrae in sagittal plane in patients with nonspecific chronic LBP (NSCLBP). Methods: In this randomized clinical trial, 30 patients...

  5. Absorbing boundary conditions for inertial random processes

    Energy Technology Data Exchange (ETDEWEB)

    Masoliver, J.; Porra, J.M. [Departament de Fisica Fonamental, Universitat de Barcelona, Diagonal, 647, 08028-Barcelona (Spain); Lindenberg, K. [Department of Chemistry and Biochemistry and Institute for Nonlinear Science, University of California, San Diego, La Jolla, California 92093-0340 (United States)

    1996-12-01

    A recent paper by J. Heinrichs [Phys. Rev. E {bold 48}, 2397 (1993)] presents analytic expressions for the first-passage times and the survival probability for a particle moving in a field of random correlated forces. We believe that the analysis there is flawed due to an improper use of boundary conditions. We compare that result, in the white noise limit, with the known exact expression of the mean exit time. {copyright} {ital 1996 The American Physical Society.}

  6. Phase Noise Compensation for OFDM Systems

    Science.gov (United States)

    Leshem, Amir; Yemini, Michal

    2017-11-01

    We describe a low complexity method for time domain compensation of phase noise in OFDM systems. We extend existing methods in several respects. First we suggest using the Karhunen-Lo\\'{e}ve representation of the phase noise process to estimate the phase noise. We then derive an improved datadirected choice of basis elements for LS phase noise estimation and present its total least square counterpart problem. The proposed method helps overcome one of the major weaknesses of OFDM systems. We also generalize the time domain phase noise compensation to the multiuser MIMO context. Finally we present simulation results using both simulated and measured phased noise. We quantify the tracking performance in the presence of residual carrier offset.

  7. Activity disturbances caused by different environmental noises

    Science.gov (United States)

    Åhrlin, U.

    1988-12-01

    An analysis was made of data obtained in investigations performed on annoyance reactions due to noise from aircraft, trains and road traffic. The aims of the analysis were to study the covariation between the extent of activity disturbances and general annoyance, to compare different noise sources with reference to activity disturbances caused, and to study the relation between the extent of annoyance reactions and noise exposure. The activity disturbances studied were speech interference effects, adverse effects on rest and sleep and awakening. Common to all three noise sources is that the extent of all activity disturbances increased with increased general annoyance. However, the rank order between the effects was different. In areas exposed to aircraft and train noise, speech interference was the effect reported by the largest proportion of respondents. Road traffic noise primarily disturbed rest and sleep. As regards train noise, it was demonstrated that although the extent of activity disturbances was comparatively high, the extent of general annoyance was lower on the whole than the extent of activity disturbances. These differences in responses may be due to differences in attitudes towards the noise sources. Even though actual noise-related effects were experienced, the degree of subjective annoyance may be determined by the type of noise source causing the effects. The dose-response relationship established for aircraft and train noise demonstrated that the extent of general annoyance varied although the noise conditions were similar. The differences were further accentuated with increasing dB(A) levels. The results from the analysis demonstrated that the use of response indices based upon different activity interferences must take into account the variations that are present between different noise sources. Weighting all activity interferences into an index and applying this universally for all noises will decrease the precision of the response

  8. Evidence of Non-extensivity in Earth's Ambient Noise

    Science.gov (United States)

    Koutalonis, Ioannis; Vallianatos, Filippos

    2017-12-01

    The study of ambient seismic noise is one of the important scientific and practical research challenges, due to its use in a number of geophysical applications. In this work, we describe Earth's ambient noise fluctuations in terms of non-extensive statistical physics. We found that Earth's ambient noise increments follow the q-Gaussian distribution. This indicates that Earth's ambient noise's fluctuations are not random and present long-term memory effects that could be described in terms of Tsallis entropy. Our results suggest that q values depend on the time length used and that the non-extensive parameter, q, converges to value q → 1 for short-time windows and a saturation value of q ≈ 1.33 for longer ones. The results are discussed from the point of view of superstatistics introduced by Beck [Contin Mech Thermodyn 16(3):293-304, 2004] and connects the q values with the system's degrees of freedom. Our work indicates that the converged (maximum) value is q = 1.33 and is related to 5 degrees of freedom.

  9. Estimation of Signal Coherence Threshold and Concealed Spectral Lines Applied to Detection of Turbofan Engine Combustion Noise

    Science.gov (United States)

    Miles, Jeffrey Hilton

    2010-01-01

    Combustion noise from turbofan engines has become important, as the noise from sources like the fan and jet are reduced. An aligned and un-aligned coherence technique has been developed to determine a threshold level for the coherence and thereby help to separate the coherent combustion noise source from other noise sources measured with far-field microphones. This method is compared with a statistics based coherence threshold estimation method. In addition, the un-aligned coherence procedure at the same time also reveals periodicities, spectral lines, and undamped sinusoids hidden by broadband turbofan engine noise. In calculating the coherence threshold using a statistical method, one may use either the number of independent records or a larger number corresponding to the number of overlapped records used to create the average. Using data from a turbofan engine and a simulation this paper shows that applying the Fisher z-transform to the un-aligned coherence can aid in making the proper selection of samples and produce a reasonable statistics based coherence threshold. Examples are presented showing that the underlying tonal and coherent broad band structure which is buried under random broadband noise and jet noise can be determined. The method also shows the possible presence of indirect combustion noise. Copyright 2011 Acoustical Society of America. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the Acoustical Society of America.

  10. Recursive framework for joint inpainting and de-noising of photographic films.

    Science.gov (United States)

    Subrahmanyam, G R K S; Rajagopalan, A N; Aravind, R

    2010-05-01

    We address the problem of inpainting noisy photographs. We present a recursive image recovery scheme based on the unscented Kalman filter (UKF) to simultaneously inpaint identified damaged portions in an image and suppress film-grain noise. Inpainting of the missing observations is guided by a mask-dependent reconstruction of the image edges. Prediction within the UKF is based on a discontinuity-adaptive Markov random field prior that attempts to preserve edges while achieving noise reduction in uniform regions. We demonstrate the capability of the proposed method with many examples.

  11. EFFECT OF NOISE DISTURBANCES ON THE RESPONSE

    Directory of Open Access Journals (Sweden)

    G. M. Alwan

    2013-05-01

    Full Text Available The present work studies the effect of noise on the dynamic response of pH, conductivity and thermocouple sensors which used into several industrial processes.Thermocouple would be proven had more stability against noise than conductivity and pH meter. The effect of noise on process signals could be condensate as low as possible by using suitable model of filter especially when the sensors were implemented to a digital computer. 

  12. Silicon Germanium Cryogenic Low Noise Amplifiers

    Science.gov (United States)

    Bardin, J. C.; Montazeri, S.; Chang, Su-Wei

    2017-05-01

    Silicon germanium heterojunction bipolar transistors have emerged in the last decade as an excellent option for use in cryogenic low noise amplifiers. This paper begins with a review of the critical developments that have led to today’s cryogenic low noise amplifiers. Next, recent work focused on minimizing the power consumption of SiGe cryogenic amplifiers is presented. Finally, open issues related to the cryogenic noise properties of SiGe HBTs are discussed.

  13. Noise modeling and analysis of an IMU-based attitude sensor: improvement of performance by filtering and sensor fusion

    Science.gov (United States)

    K., Nirmal; A. G., Sreejith; Mathew, Joice; Sarpotdar, Mayuresh; Suresh, Ambily; Prakash, Ajin; Safonova, Margarita; Murthy, Jayant

    2016-07-01

    We describe the characterization and removal of noises present in the Inertial Measurement Unit (IMU) MPU- 6050, which was initially used in an attitude sensor, and later used in the development of a pointing system for small balloon-borne astronomical payloads. We found that the performance of the IMU degraded with time because of the accumulation of different errors. Using Allan variance analysis method, we identified the different components of noise present in the IMU, and verified the results by the power spectral density analysis (PSD). We tried to remove the high-frequency noise using smooth filters such as moving average filter and then Savitzky Golay (SG) filter. Even though we managed to filter some high-frequency noise, these filters performance wasn't satisfactory for our application. We found the distribution of the random noise present in IMU using probability density analysis and identified that the noise in our IMU was white Gaussian in nature. Hence, we used a Kalman filter to remove the noise and which gave us good performance real time.

  14. Weighted Measurement Fusion White Noise Deconvolution Filter with Correlated Noise for Multisensor Stochastic Systems

    Directory of Open Access Journals (Sweden)

    Xin Wang

    2012-01-01

    Full Text Available For the multisensor linear discrete time-invariant stochastic control systems with different measurement matrices and correlated noises, the centralized measurement fusion white noise estimators are presented by the linear minimum variance criterion under the condition that noise input matrix is full column rank. They have the expensive computing burden due to the high-dimension extended measurement matrix. To reduce the computing burden, the weighted measurement fusion white noise estimators are presented. It is proved that weighted measurement fusion white noise estimators have the same accuracy as the centralized measurement fusion white noise estimators, so it has global optimality. It can be applied to signal processing in oil seismic exploration. A simulation example for Bernoulli-Gaussian white noise deconvolution filter verifies the effectiveness.

  15. Noise-induced bursting in Rulkov model

    Science.gov (United States)

    Ryashko, L.; Slepukhina, E.; Nasyrova, V.

    2016-10-01

    A problem of mathematical modeling and analysis of the stochastic phenomena in neuronal activity is considered. As a basic example, we use the nonlinear Rulkov map-based neuron model with random disturbances. In deterministic case, this one-dimensional model demonstrates quiescence, tonic and chaotic spiking regimes. We show that due to presence of random disturbances, a new regime of noise-induced bursting is generated not only in bistability zones, but also in monostability zones. To estimate noise intensity corresponding to the onset of bursting, the stochastic sensitivity technique and confidence domains method are applied. An effciency of our approach is confirmed by the statistics of interspike intervals.

  16. Noise and Hearing Protection

    Science.gov (United States)

    ... often becomes permanent. Some people react to loud noise with anxiety and irritability, an increase in pulse rate and blood pressure, or an increase in stomach acid. Very loud noise can reduce efficiency in performing difficult tasks by ...

  17. Long term memory for noise: evidence of robust encoding of very short temporal acoustic patterns.

    Directory of Open Access Journals (Sweden)

    Jayalakshmi Viswanathan

    2016-11-01

    Full Text Available Recent research has demonstrated that humans are able to implicitly encode and retain repeating patterns in meaningless auditory noise. Our study aimed at testing the robustness of long-term implicit recognition memory for these learned patterns. Participants performed a cyclic/non-cyclic discrimination task, during which they were presented with either 1-s cyclic noises (CNs (the two halves of the noise were identical or 1-s plain random noises (Ns. Among CNs and Ns presented once, target CNs were implicitly presented multiple times within a block, and implicit recognition of these target CNs was tested 4 weeks later using a similar cyclic/non-cyclic discrimination task. Furthermore, robustness of implicit recognition memory was tested by presenting participants with looped (shifting the origin and scrambled (chopping sounds into 10- and 20-ms bits before shuffling versions of the target CNs. We found that participants had robust implicit recognition memory for learned noise patterns after 4 weeks, right from the first presentation. Additionally, this memory was remarkably resistant to acoustic transformations, such as looping and scrambling of the sounds. Finally, implicit recognition of sounds was dependent on participant’s discrimination performance during learning. Our findings suggest that meaningless temporal features as short as 10 ms can be implicitly stored in long-term auditory memory. Moreover, successful encoding and storage of such fine features may vary between participants, possibly depending on individual attention and auditory discrimination abilities.

  18. Mixed Mode Oscillations and Synchronous Activity in Noise Induced Modified Morris-Lecar Neural System

    Science.gov (United States)

    Upadhyay, Ranjit Kumar; Mondal, Argha; Teka, Wondimu W.

    The modified three-dimensional (3D) Morris-Lecar (M-L) model is very useful to understand the spiking activities of neurons. The present article addresses the random dynamical behavior of a modified M-L model driven by a white Gaussian noise with mean zero and unit spectral density. The applied stimulus can be expressed as a random term. Such random perturbations are represented by a white Gaussian noise current added through the electrical potential of membrane of the excitatory principal cells. The properties of the stochastic system (perturbed one) and noise induced mixed mode oscillation are analyzed. The Lyapunov spectrum is computed to present the nature of the system dynamics. The noise intensity is varied while keeping fixed the predominant parameters of the model in their ranges and also observed the changes in the dynamical behavior of the system. The dynamical synchronization is studied in the coupled M-L systems interconnected by excitatory and inhibitory neurons with noisy electrical coupling and verified with similarity functions. This result suggests the potential benefits of noise and noise induced oscillations which have been observed in real neurons and how that affects the dynamics of the neural model as well as the coupled systems. The analysis reports that the modified M-L system which has the limit cycle behavior can show a type of phase locking behavior which follows either period adding (i.e. 1:1, 2:1, 3:1, 4:1) sequences or Farey sequences. For the coupled neural systems, complete synchronization is shown for sufficient noisy coupling strength.

  19. Noise in mesoscopic physics

    OpenAIRE

    Martin, Thierry

    2005-01-01

    This is a course on noise which covers some of the scattering theory for normal metals, Hanbury Brown and Twiss analogs for noise correlations with electrons, noise correlations in superconducting/normal metal junctions. Entanglement in such NS systems is described with a criterion for violating Bell inegalities. The last section is devoted to the perturbative derivation of noise in a particular one dimensional correlated electron system (Luttinger liquid): edge states in the fractional quant...

  20. The effect of noise exposure on insulin sensitivity in mice may be mediated by the JNK/IRS1 pathway.

    Science.gov (United States)

    Liu, Lijie; Fang, Cong; Yang, Jing; Zhang, Hongyu; Huang, Yi; Xuan, Chuanying; Wang, Yongfang; Li, Shengwei; Sha, Jun; Zha, Mingming; Guo, Min

    2018-02-12

    Epidemiological studies have suggested that noise exposure may increase the risk of type 2 diabetes mellitus (T2DM), and experimental studies have demonstrated that noise exposure can induce insulin resistance in rodents. The aim of the present study was to explore noise-induced processes underlying impaired insulin sensitivity in mice. Male ICR mice were randomly divided into four groups: a control group without noise exposure and three noise groups exposed to white noise at a 95-dB sound pressure level for 4 h/day for 1, 10, or 20 days (N1D, N10D, and N20D, respectively). Systemic insulin sensitivity was evaluated at 1 day, 1 week, and 1 month post-noise exposure (1DPN, 1WPN, and 1MPN) via insulin tolerance tests (ITTs). Several insulin-related processes, including the phosphorylation of Akt, IRS1, and JNK in the animals' skeletal muscles, were examined using standard immunoblots. Biomarkers of inflammation (circulating levels of TNF-α and IL-6) and oxidative stress (SOD and CAT activities and MDA levels in skeletal muscles) were measured via chemical analyses. The data obtained in this study showed the following: (1) The impairment of systemic insulin sensitivity was transient in the N1D group but prolonged in the N10D and N20D groups. (2) Noise exposure led to enhanced JNK phosphorylation and IRS1 serine phosphorylation as well as reduced Akt phosphorylation in skeletal muscles in response to exogenous insulin stimulation. (3) Plasma levels of TNF-α and IL-6, CAT activity, and MDA concentrations in skeletal muscles were elevated after 20 days of noise exposure. Impaired insulin sensitivity in noise-exposed mice might be mediated by an enhancement of the JNK/IRS1 pathway. Inflammation and oxidative stress might contribute to insulin resistance after chronic noise exposure.

  1. Residential exposure to traffic noise and risk for non-hodgkin lymphoma among adults.

    Science.gov (United States)

    Sørensen, Mette; Harbo Poulsen, Aslak; Ketzel, Matthias; Oksbjerg Dalton, Susanne; Friis, Søren; Raaschou-Nielsen, Ole

    2015-10-01

    Exposure to traffic noise may result in stress and sleep disturbances, which have been associated with impairment of the immune system. People with weakened immune systems are known to have a higher risk for non-Hodgkin lymphoma (NHL). We aimed to determine whether traffic noise was associated with risk for NHL in a nationwide case-control study. We identified 2753 cases aged 30-84 years with a primary diagnosis of NHL in Denmark between 1992 and 2010. For each case we selected two random population controls, matched on sex and year of birth. Road traffic and railway noise were calculated, and airport noise was estimated for all present and historical residential addresses of cases and controls from 1987 to 2010. Associations between traffic noise and risk for NHL were estimated using conditional logistic regression, adjusted for disposable income, education, cohabiting status and comorbidity. We found that a 5-year time-weighted mean of road traffic noise above 65 dB was associated with an 18% higher risk for NHL (95% confidence interval (CI) 1.01-1.37) when compared to road traffic noise below 55 dB, whereas for exposure between 55 and 65 dB no association was found (odds ratio: 0.98; 95% CI: 0.88-1.08). In analyzes of NHL subtypes, we found no association between road traffic noise and risk for T-cell lymphoma, whereas increased risks for B-cell lymphoma and unspecified lymphomas were observed at exposures above 65 dB. In conclusion, our nationwide study may indicate that high exposure to traffic noise is associated with higher NHL risk. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Active Chevrons for Jet Noise Reduction

    Science.gov (United States)

    Depuru-Mohan, N. K.; Doty, M. J.

    2017-01-01

    Jet noise is often a dominant component of aircraft noise, particularly at takeoff. To meet the stringent noise regulations, the aircraft industry is in a pressing need of advanced noise reduction concepts. In the present study, the potential of piezoelectrically-activated chevrons for jet noise reduction was experimentally investigated. The perturbations near the nozzle exit caused by piezoelectrically-activated chevrons could be used to modify the growth rate of the mixing layer and thereby potentially reduce jet noise. These perturbations are believed to increase the production of small-scale disturbances at the expense of large-scale turbulent structures. These large-scale turbulent structures are responsible for the dominant portion of the jet mixing noise, particularly low-frequency noise. Therefore, by exciting the static chevron geometry through piezoelectric actuators, an additional acoustic benefit could possibly be achieved. To aid in the initial implementation of this concept, several flat-faced faceted nozzles (four, six, and eight facets) were investigated. Among the faceted nozzles, it was found that the eight-faceted nozzle behaves very similarly to the round nozzle. Furthermore, among the faceted nozzles with static chevrons, the four-faceted nozzle with static chevrons was found to be most effective in terms of jet noise reduction. The piezoelectrically-activated chevrons reduced jet noise up to 2 dB compared to the same nozzle geometry without excitation. This benefit was observed over a wide range of excitation frequencies by applying very low voltages to the piezoelectric actuators.

  3. Association between Triclosan-Coated Sutures for Abdominal Wall Closure and Incisional Surgical Site Infection after Open Surgery in Patients Presenting with Fecal Peritonitis: A Randomized Clinical Trial.

    Science.gov (United States)

    Ruiz-Tovar, Jaime; Alonso, Natalia; Morales, Vicente; Llavero, Carolina

    2015-10-01

    A factor that may influence the incidence of surgical site infections (SSIs) is the suture used for closure of the abdominal wall because bacteria may adhere to the suture material. Sutures can be coated with antibacterial substances that may reduce the bacterial load in the incision. The aim of this study was to evaluate the effect of triclosan-coated sutures used in abdominal wall closure in patients with fecal peritonitis. A randomized study was performed. Inclusion criteria were intra-operative diagnosis of fecal peritonitis secondary to acute diverticulitis perforation, neoplastic tumor perforation, or colorectal anastomotic leak of previous elective colorectal resection. The patients were randomly assigned to either abdominal wall closure with triclosan-coated sutures (group 1) or sutures without triclosan (group 2). Fifty patients were included in group 1 and 51 in group 2. The incisional SSI rate was 10% in group 1 and 35.3% in group 2 (p=0.004; odds ratio [OR]=0.204; 95% confidence interval [CI] 0.069-0.605). A significant reduction in SSIs caused by Escherichia coli and Enterococcus faecalis was observed in group 2. The use of triclosan-coated sutures in fecal peritonitis surgery reduces the incidence of incisional SSI.

  4. Introducing Randomness into First-Order and Second-Order Deterministic Differential Equations

    Directory of Open Access Journals (Sweden)

    John F. Moxnes

    2010-01-01

    Full Text Available We incorporate randomness into deterministic theories and compare analytically and numerically some well-known stochastic theories: the Liouville process, the Ornstein-Uhlenbeck process, and a process that is Gaussian and exponentially time correlated (Ornstein-Uhlenbeck noise. Different methods of achieving the marginal densities for correlated and uncorrelated noise are discussed. Analytical results are presented for a deterministic linear friction force and a stochastic force that is uncorrelated or exponentially correlated.

  5. Quantum optics in multiple scattering random media

    DEFF Research Database (Denmark)

    Lodahl, Peter

    Quantum Optics in Multiple Scattering Random Media Peter Lodahl Research Center COM, Technical University of Denmark, Dk-2800 Lyngby, Denmark. Coherent transport of light in a disordered random medium has attracted enormous attention both from a fundamental and application point of view. Coherent...... quantum optics in multiple scattering media and novel fundamental phenomena have been predicted when examining quantum fluctuations instead of merely the intensity of the light [1]. Here I will present the first experimental study of the propagation of quantum noise through an elastic, multiple scattering...

  6. SDE based regression for random PDEs

    KAUST Repository

    Bayer, Christian

    2016-01-06

    A simulation based method for the numerical solution of PDE with random coefficients is presented. By the Feynman-Kac formula, the solution can be represented as conditional expectation of a functional of a corresponding stochastic differential equation driven by independent noise. A time discretization of the SDE for a set of points in the domain and a subsequent Monte Carlo regression lead to an approximation of the global solution of the random PDE. We provide an initial error and complexity analysis of the proposed method along with numerical examples illustrating its behaviour.

  7. Aero-acoustic noise of wind turbines. Noise prediction models

    Energy Technology Data Exchange (ETDEWEB)

    Maribo Pedersen, B. [ed.

    1997-12-31

    Semi-empirical and CAA (Computational AeroAcoustics) noise prediction techniques are the subject of this expert meeting. The meeting presents and discusses models and methods. The meeting may provide answers to the following questions: What Noise sources are the most important? How are the sources best modeled? What needs to be done to do better predictions? Does it boil down to correct prediction of the unsteady aerodynamics around the rotor? Or is the difficult part to convert the aerodynamics into acoustics? (LN)

  8. Noise Properties of CMOS Current Conveyors

    DEFF Research Database (Denmark)

    Bruun, Erik

    1996-01-01

    The definition of the current conveyor is presented and it is shown how different generations of current conveyors can all be combined into a single definition of a multiple-output second generation current conveyor (CCII). Next, noise sources are introduced into the model, and a general noise...... model for the current conveyor is established. This model is used for the analysis of selected examples of current conveyor based operational amplifier configurations and the relative merits with respect to the noise performance of these configurations are discussed. Finally, the noise model...... is developed for a CMOS current conveyor implementation, and optimization strategies for noise reduction are discussed. It is concluded that a class AB implementation provides more flexibility than does a class A configuration. In both cases it is essential to design low noise current mirrors and current...

  9. Complex diffusion process for noise reduction

    DEFF Research Database (Denmark)

    Nadernejad, Ehsan; Barari, A.

    2014-01-01

    Signal de-noising and restoration is an essential step for many signal processing algorithms and applications. One of the most common problems is the removal of some interesting structures in the signal during the restoration process. The capability of methods based on partial differential...... equations (PDEs) in image restoration and de-noising prompted many researchers to search for an improvement in the technique. In this paper, a new method is presented for signal de-noising, based on PDEs and Schrodinger equations, named as complex diffusion process (CDP). This method assumes that variations...... for signal de-noising. To evaluate the performance of the proposed method, a number of experiments have been performed using Sinusoid, multi-component and FM signals cluttered with noise. The results indicate that the proposed method outperforms the approaches for signal de-noising known in prior art....

  10. Tools for noise characterization in Virgo

    Energy Technology Data Exchange (ETDEWEB)

    Accadia, T; Belletoile, A [Laboratoire d' Annecy-le-Vieux de Physique des Particules (LAPP), IN2P3/CNRS, Universite de Savoie, F-74941 Annecy-le-Vieux (France); Ballardin, G [European Gravitational Observatory (EGO), I-56021 Cascina (PI) (Italy); Barsuglia, M; Bouhou, B [AstroParticule et Cosmologie (APC), CNRS: UMR7164-IN2P3-Observatoire de Paris-Universite Denis Diderot-Paris 7 - CEA : DSM/IRFU (France); Bonnand, R [Laboratoire des Materiaux Avances (LMA), IN2P3/CNRS, F-69622 Villeurbanne, Lyon (France); Acernese, F; Antonucci, F; Astone, P; Barone, F; Bauer, Th S; Beker, M G; Birindelli, S; Bitossi, M; Bizouard, M A; Blom, M; Bondu, F; Bonelli, L; Boschi, V; Bosi, L, E-mail: elena.cuoco@ego-gw.i

    2010-08-01

    Several software tools were used to perform on-line and of-line noise analysis as a support to commissioning activities, to monitor the rate of glitches, the occurrence of non stationary noise, the presence of environmental contamination, the behavior of narrow spectral features and the coherence with auxiliary channels. We report about the use of these tools to study the main sources of identified noise: broadband, spectral lines and glitches. Plans for the upgrade of the tools will be presented, for example for lines identification purpose to let the scientists in control room do noise characterization in an easier way.

  11. Random phase-free computer-generated hologram

    CERN Document Server

    Shimobaba, Tomoyoshi

    2015-01-01

    Addition of random phase to the object light is required in computer-generated holograms (CGHs) to widely diffuse the object light and to avoid its concentration on the CGH; however, this addition causes considerable speckle noise in the reconstructed image. For improving the speckle noise problem, techniques such as iterative phase retrieval algorithms and multi-random phase method are used; however, they are time consuming and are of limited effectiveness. Herein, we present a simple and computationally inexpensive method that drastically improves the image quality and reduces the speckle noise by multiplying the object light with the virtual convergence light. Feasibility of the proposed method is shown using simulations and optical reconstructions; moreover, we apply it to lens-less zoom-able holographic projection. The proposed method is useful for the speckle problems in holographic applications.

  12. Direct-reading dial for noise temperature and noise resistance

    DEFF Research Database (Denmark)

    Diamond, J.M.

    1967-01-01

    An attenuator arrangement for a noise generator is described. The scheme permits direct reading of both noise resistance and noise temperature¿the latter with a choice of source resistance.......An attenuator arrangement for a noise generator is described. The scheme permits direct reading of both noise resistance and noise temperature¿the latter with a choice of source resistance....

  13. Comparison of non-directive counselling and cognitive behaviour therapy for patients presenting in general practice with an ICD-10 depressive episode: a randomized control trial.

    Science.gov (United States)

    King, M; Marston, L; Bower, P

    2014-07-01

    Most evidence in the UK on the effectiveness of brief therapy for depression concerns cognitive behaviour therapy (CBT). In a trial published in 2000, we showed that non-directive counselling and CBT were equally effective in general practice for patients with depression and mixed anxiety and depression. Our results were criticized for including patients not meeting diagnostic criteria for a depressive disorder. In this reanalysis we aimed to compare the effectiveness of the two therapies for patients with an ICD-10 depressive episode. Patients with an ICD-10 depressive episode or mixed anxiety and depression were randomized to counselling, CBT or usual general practitioner (GP) care. Counsellors provided nondirective, interpersonal counselling following a manual that we developed based on the work of Carl Rogers. Cognitive behaviour therapists provided CBT also guided by a manual. Modelling was carried out using generalized estimating equations with the multiply imputed datasets. Outcomes were mean scores on the Beck Depression Inventory, Brief Symptom Inventory, and Social Adjustment Scale at 4 and 12 months. A total of 134 participants were randomized to CBT, 126 to counselling and 67 to usual GP care. We undertook (1) an interaction analysis using all 316 patients who were assigned a diagnosis and (2) a head-to-head comparison using only those 130 (41%) participants who had an ICD-10 depressive episode at baseline. CBT and counselling were both superior to GP care at 4 months but not at 12 months. There was no difference in the effectiveness of the two psychological therapies. We recommend that national clinical guidelines take our findings into consideration in recommending effective alternatives to CBT.

  14. Influence of core stability exercise on lumbar vertebral instability in patients presented with chronic low back pain: A randomized clinical trial.

    Science.gov (United States)

    Javadian, Yahya; Akbari, Mohammad; Talebi, Ghoadamali; Taghipour-Darzi, Mohammad; Janmohammadi, Naser

    2015-01-01

    Excessive lumbar vertebrae translation and rotation in sagittal plane has been attributed as an associated factor of lumbar segmental instability (LSI) and low back pain (LBP). Reduction of these abnormalities improves back pain. The aim of this study was to investigate the effect of core stability exercise on the translation and rotation of lumbar vertebrae in sagittal plane in patients with nonspecific chronic LBP (NSCLBP). In this randomized clinical trial, 30 patients with NSCLBP due to LSI were included. The participants were randomly divided into two groups of treatment and control. The treatment group received general exercises plus core stability exercise for 8 weeks whereas; the control group received only general exercises. The magnitude of translation (mm) and rotation (deg) of lumbar vertebrae in the sagittal plane was determined by radiography in flexion and extension at baseline and after intervention. The primary outcome measures were to determine the mean changes from baseline in translation and rotation of the lumbar vertebrae in the sagittal plane after 8 weeks of intervention in each group. The secondary outcome was to compare the two groups in regard to translation and rotation of the lumbar vertebrae at the end of the study period. Data were analyzed using paired t-test and independent t-test. Thirty patients aged 18-40 years old with clinical diagnosis of NSCLBP entered the study. Compared with baseline values, mean value of translation and rotation of the lumbar vertebra reduced significantly in both groups (Pcore stability exercises plus general exercises are more efficient than general exercises alone in the improvement of excessive lumbar vertebrae translation and rotation.

  15. Power spectral density of 3D noise

    Science.gov (United States)

    Haefner, David P.

    2017-05-01

    When evaluated with a spatially uniform irradiance, an imaging sensor exhibits both spatial and temporal variations, which can be described as a three-dimensional (3D) random process considered as noise. In the 1990s, NVESD engineers developed an approximation to the 3D power spectral density (PSD) for noise in imaging systems known as 3D noise. This correspondence describes the decomposition of the full 3D PSD into the familiar components from the 3D Noise model. The standard 3D noise method assumes spectrally (spatio-temporal) white random processes, which is demonstrated to be atypically in the case with complex modern imaging sensors. Using the spectral shape allows for more appropriate analysis of the impact of the noise of the sensor. The processing routines developed for this work consider finite memory constraints and utilize Welch's method for unbiased PSD estimation. In support of the reproducible research effort, the Matlab functions associated with this work can be found on the Mathworks file exchange [1].

  16. A new measurement method for separating airborne and structureborne aircraft interior noise

    Science.gov (United States)

    Mcgary, M. C.; Mayes, W. H.

    1983-01-01

    It is pointed out that interior noise levels of propeller driven aircraft are substantially higher than levels measured for other types of CTOL aircraft. Reduction of interior noise of such aircraft requires a knowledge of the relative importance of the acoustic and structural noise transmission paths. Noise entering the aircraft interior via an acoustic path is the noise radiated by an external noise source (propellers, exhaust noise), which propagates through the acoustic medium (air) and is then transmitted through the aircraft fuselage. This type of incoming noise is referred to as airborne noise. Noise entering the aircraft interior via a structural path is the noise which has its source in the vibrational energy which has been transmitted through the structure from a remote vibrational energy source (engines, wind flutter). This type of incoming noise is referred to as structureborne noise. A new method for separating airborne and structureborne noise is presented. It is based on two-microphone cross spectral acoustic intensity measurements.

  17. Investigations of certain problems in reactor noise diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Karlsson, Joakim

    1997-06-01

    A number of problems in reactor noise diagnostics have been investigated within the framework of the present thesis. The papers presented cover three relatively different areas, namely neutron noise induced by small vibrations of a strong absorber, the decomposition of noise in BWRs with application to stability monitoring, and fluctuation analysis of soft x-ray signals from fusion plasmas. 18 refs, 6 figs.

  18. Noise properties of graphene films

    Science.gov (United States)

    Sun, Nan; Liu, Xinyu; Arnold, Gerald; Ruggiero, Steven; Department of Physics Team

    2013-03-01

    We present results for the noise characteristics of graphene flakes on SiO2 as a function of gate bias. Our results are in accord with a new tunnel/trap model based on the interaction of graphene carriers with the underlying substrate, which incorporates trap position, energy, and barrier height for tunneling into a given trap, along with the band-structure of the graphene. We will also discuss recent work on the properties of MBE-grown GaAs on graphene, in the context of noise in spin transport.

  19. Reykjanes ambient noise reflection interferometry

    NARCIS (Netherlands)

    Verdel, Arie; Wedemeijer, Harry; Paap, B; Vandeweijer, Vincent; Weemstra, C.; Jousset, Philippe; Franke, Steven; Blanck, Hanna; Águstsson, K.; Hersir, Gylfi Páll

    2016-01-01

    We present results from the application of ambient noise seismic interferometry (ANSI) to data that were recorded continuously in 2014 and 2015 at Iceland’s peninsula Reykjanes. The objective of this study is the retrieval of reflected body waves (P-waves) that provide high-resolution

  20. Cryogenic MMIC Low Noise Amplifiers

    Science.gov (United States)

    Weinreb, S.; Gaier, T.; Fernandez, J.; Erickson, N.; Wielgus, J.

    2000-01-01

    Monolithic (MMIC) and discrete transistor (MIC) low noise amplifiers are compared on the basis of performance, cost, and reliability. The need for cryogenic LNA's for future large microwave arrays for radio astronomy is briefly discussed and data is presented on a prototype LNA for the 1 to 10 GZH range along with a very wideband LNA for the 1 to 60 GHz range.

  1. Facilitation of Retention by White Noise

    Science.gov (United States)

    Baumeister, Alfred A.; Kistler, Doris

    1975-01-01

    This study attempted to determine if white noise (an arousing stimulus), when presented at the time of recall, facilitates performance of second and fifth grade students, and if this effect generalizes across different kinds of learning tasks. Findings indicate that white noise produces improvements in performance in both age groups. (GO)

  2. General considerations of noise in microphone preamplifiers

    NARCIS (Netherlands)

    van der Donk, A.G.H.; van der Donk, A.G.H.; Voorthuyzen, J.A.; Voorthuyzen, J.A.; Bergveld, Piet

    1991-01-01

    In this paper a study of the noise performance of electret microphone systems as a part of hearing aids is presented. The signal-to-noise ratio of the microphone-preamplifier combination, containing a field-effect transistor (FET) and a high value resistive bias element in a hybrid configuration, is

  3. Noise exposure under hyperbaric conditions

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-03-01

    Objective evidence exists that divers demonstrate a hearing deficit greater than would be expected from ageing effects alone. Deafness in divers may be caused by a number of factors other than exposure to excessive noise levels, eg barotrauma, ear infection etc. This review concentrates on the concern that exposure of commercial divers to noise while at work may cause a hearing deficit. Sound pressure levels recorded both underwater and in diving chambers often exceed those allowable to workers onshore. However, the sound perceived by the diver is modified both in amplitude and in frequency when he is either underwater or in pressurised chambers. Broadly the effect of this modification is to attenuate the sound and thus offer some protection from high noise levels. The degree of attentuation varies with the frequency of the sound, however it is also possible under specific conditions associated with gas density for the sensitivity to particular frequencies to be amplified above that for normal atmospheric air. The levels of sound observed from some underwater tools are of concern even after allowing for a significant de-sensitisation of the divers` hearing. Reports of tinnitus and temporary hearing loss following a dive are sure signs that the noise levels have been harmful. It is not possible at present to describe risk criteria for hearing damage due to noise exposure associated with diving. (author)

  4. Random vibrations theory and practice

    CERN Document Server

    Wirsching, Paul H; Ortiz, Keith

    1995-01-01

    Random Vibrations: Theory and Practice covers the theory and analysis of mechanical and structural systems undergoing random oscillations due to any number of phenomena— from engine noise, turbulent flow, and acoustic noise to wind, ocean waves, earthquakes, and rough pavement. For systems operating in such environments, a random vibration analysis is essential to the safety and reliability of the system. By far the most comprehensive text available on random vibrations, Random Vibrations: Theory and Practice is designed for readers who are new to the subject as well as those who are familiar with the fundamentals and wish to study a particular topic or use the text as an authoritative reference. It is divided into three major sections: fundamental background, random vibration development and applications to design, and random signal analysis. Introductory chapters cover topics in probability, statistics, and random processes that prepare the reader for the development of the theory of random vibrations a...

  5. World Wide Distribution of Published Ambient Noise Data.

    Science.gov (United States)

    The report presents the numerical distribution of reports contained in the AESD computerized ambient noise bibliography as a function of ocean areas...A numerical break down according to topics directly relating to ambient noise is also given. (Author)

  6. Noise from wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Fegeant, Olivier [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Building Sciences

    2002-02-01

    A rapid growth of installed wind power capacity is expected in the next few years. However, the siting of wind turbines on a large scale raises concerns about their environmental impact, notably with respect to noise. To this end, variable speed wind turbines offer a promising solution for applications in densely populated areas like the European countries, as this design would enable an efficient utilisation of the masking effect due to ambient noise. In rural and recreational areas where wind turbines are sited, the ambient noise originates from the action of wind on the vegetation and about the listener's ear (pseudo-noise). It shows a wind speed dependence similar to that of the noise from a variable speed wind turbine and can therefore mask the latter for a wide range of conditions. However, a problem inherent to the design of these machines is their proclivity to pure tone generation, because of the enhanced difficulty of avoiding structural resonances in the mechanical parts. Pure tones are deemed highly annoying and are severely regulated by most noise policies. In relation to this problem, the vibration transmission of structure-borne sound to the tower of the turbine is investigated, in particular when the tower is stiffened at its upper end. Furthermore, since noise annoyance due to wind turbine is mostly a masking issue, the wind-related sources of ambient noise are studied and their masking potentials assessed. With this aim, prediction models for wind-induced vegetation noise and pseudo-noise have been developed. Finally, closely related to the effect of masking, is the difficulty, regularly encountered by local authorities and wind farm developers, to measure noise immission from wind turbines. A new measurement technique has thus been developed in the course of this work. Through improving the signal-to-noise ratio between wind turbine noise and ambient noise, the new technique yields more accurate measurement results.

  7. Exposure-response relationships for annoyance by wind turbine noise: A comparison with other stationary sources

    NARCIS (Netherlands)

    Janssen, S.A.; Vos, H.; Eisses, A.R.; Pedersen, E.

    2009-01-01

    There are indications that, given a certain level of noise exposure, the expected annoyance by wind turbine noise is higher than that by noise from other sources such as industrial noise or transportation noise. The aim of the present study was to establish the exposure-response relationship between

  8. Cortical signal-in-noise coding varies by noise type, signal-to-noise ratio, age, and hearing status.

    Science.gov (United States)

    Maamor, Nashrah; Billings, Curtis J

    2017-01-01

    The purpose of this study was to determine the effects of noise type, signal-to-noise ratio (SNR), age, and hearing status on cortical auditory evoked potentials (CAEPs) to speech sounds. This helps to explain the hearing-in-noise difficulties often seen in the aging and hearing impaired population. Continuous, modulated, and babble noise types were presented at varying SNRs to 30 individuals divided into three groups according to age and hearing status. Significant main effects of noise type, SNR, and group were found. Interaction effects revealed that the SNR effect varies as a function of noise type and is most systematic for continuous noise. Effects of age and hearing loss were limited to CAEP latency and were differentially modulated by energetic and informational-like masking. It is clear that the spectrotemporal characteristics of signals and noises play an important role in determining the morphology of neural responses. Participant factors such as age and hearing status, also play an important role in determining the brain's response to complex auditory stimuli and contribute to the ability to listen in noise. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  9. Transform Domain Robust Variable Step Size Griffiths' Adaptive Algorithm for Noise Cancellation in ECG

    Science.gov (United States)

    Hegde, Veena; Deekshit, Ravishankar; Satyanarayana, P. S.

    2011-12-01

    The electrocardiogram (ECG) is widely used for diagnosis of heart diseases. Good quality of ECG is utilized by physicians for interpretation and identification of physiological and pathological phenomena. However, in real situations, ECG recordings are often corrupted by artifacts or noise. Noise severely limits the utility of the recorded ECG and thus needs to be removed, for better clinical evaluation. In the present paper a new noise cancellation technique is proposed for removal of random noise like muscle artifact from ECG signal. A transform domain robust variable step size Griffiths' LMS algorithm (TVGLMS) is proposed for noise cancellation. For the TVGLMS, the robust variable step size has been achieved by using the Griffiths' gradient which uses cross-correlation between the desired signal contaminated with observation or random noise and the input. The algorithm is discrete cosine transform (DCT) based and uses symmetric property of the signal to represent the signal in frequency domain with lesser number of frequency coefficients when compared to that of discrete Fourier transform (DFT). The algorithm is implemented for adaptive line enhancer (ALE) filter which extracts the ECG signal in a noisy environment using LMS filter adaptation. The proposed algorithm is found to have better convergence error/misadjustment when compared to that of ordinary transform domain LMS (TLMS) algorithm, both in the presence of white/colored observation noise. The reduction in convergence error achieved by the new algorithm with desired signal decomposition is found to be lower than that obtained without decomposition. The experimental results indicate that the proposed method is better than traditional adaptive filter using LMS algorithm in the aspects of retaining geometrical characteristics of ECG signal.

  10. Eliminating thermal violin spikes from LIGO noise

    Energy Technology Data Exchange (ETDEWEB)

    Santamore, D. H.; Levin, Yuri

    2001-08-15

    We have developed a scheme for reducing LIGO suspension thermal noise close to violin-mode resonances. The idea is to monitor directly the thermally induced motion of a small portion of (a 'point' on) each suspension fiber, thereby recording the random forces driving the test-mass motion close to each violin-mode frequency. One can then suppress the thermal noise by optimally subtracting the recorded fiber motions from the measured motion of the test mass, i.e., from the LIGO output. The proposed method is a modification of an analogous but more technically difficult scheme by Braginsky, Levin and Vyatchanin for reducing broad-band suspension thermal noise. The efficiency of our method is limited by the sensitivity of the sensor used to monitor the fiber motion. If the sensor has no intrinsic noise (i.e. has unlimited sensitivity), then our method allows, in principle, a complete removal of violin spikes from the thermal-noise spectrum. We find that in LIGO-II interferometers, in order to suppress violin spikes below the shot-noise level, the intrinsic noise of the sensor must be less than {approx}2 x 10{sup -13} cm/Hz. This sensitivity is two orders of magnitude greater than that of currently available sensors.

  11. Active noise reduction systems in ducts

    Science.gov (United States)

    Tichy, J.; Poole, L. A.; Warnaka, G. E.

    1984-12-01

    Fundamentals of the theory of the sound propagation in ducts with perfectly reflecting walls, relevant to noise reduction systems, is summarized. A brief historical review of the active sound cancellation techniques is given. Systems based on time invariant parameters are analyzed and their inherited drawbacks outlined. A new generation of systems using controllers based on modified adaptive LMS algorithm is described. The measurements in an experimental duct show that the random noise can be reduced by 25-30 dB, while the noise with line spectra can be decreased by up to 40 dB. Good success is also reported with impulse signals which have random time intervals between the pulses.

  12. Noise and fluctuations an introduction

    CERN Document Server

    MacDonald, D K C

    2006-01-01

    An understanding of fluctuations and their role is both useful and fundamental to the study of physics. This concise study of random processes offers graduate students and research physicists a survey that encompasses both the relationship of Brownian Movement with statistical mechanics and the problem of irreversible processes. It outlines the basics of the physics involved, without the strictures of mathematical rigor.The three-part treatment starts with a general survey of Brownian Movement, including electrical Brownian Movement and ""shot-noise,"" Part two explores correlation, frequency

  13. Removing Noise From Pyrosequenced Amplicons

    Directory of Open Access Journals (Sweden)

    Davenport Russell J

    2011-01-01

    Full Text Available Abstract Background In many environmental genomics applications a homologous region of DNA from a diverse sample is first amplified by PCR and then sequenced. The next generation sequencing technology, 454 pyrosequencing, has allowed much larger read numbers from PCR amplicons than ever before. This has revolutionised the study of microbial diversity as it is now possible to sequence a substantial fraction of the 16S rRNA genes in a community. However, there is a growing realisation that because of the large read numbers and the lack of consensus sequences it is vital to distinguish noise from true sequence diversity in this data. Otherwise this leads to inflated estimates of the number of types or operational taxonomic units (OTUs present. Three sources of error are important: sequencing error, PCR single base substitutions and PCR chimeras. We present AmpliconNoise, a development of the PyroNoise algorithm that is capable of separately removing 454 sequencing errors and PCR single base errors. We also introduce a novel chimera removal program, Perseus, that exploits the sequence abundances associated with pyrosequencing data. We use data sets where samples of known diversity have been amplified and sequenced to quantify the effect of each of the sources of error on OTU inflation and to validate these algorithms. Results AmpliconNoise outperforms alternative algorithms substantially reducing per base error rates for both the GS FLX and latest Titanium protocol. All three sources of error lead to inflation of diversity estimates. In particular, chimera formation has a hitherto unrealised importance which varies according to amplification protocol. We show that AmpliconNoise allows accurate estimates of OTU number. Just as importantly AmpliconNoise generates the right OTUs even at low sequence differences. We demonstrate that Perseus has very high sensitivity, able to find 99% of chimeras, which is critical when these are present at high

  14. Noise sensitivity, rather than noise level, predicts the non-auditory effects of noise in community samples: a population-based survey

    OpenAIRE

    Park, Jangho; Chung, Seockhoon; Lee, Jiho; Sung, Joo Hyun; Cho, Seung Woo; Sim, Chang Sun

    2017-01-01

    Abstract Background Excessive noise affects human health and interferes with daily activities. Although environmental noise may not directly cause mental illness, it may accelerate and intensify the development of latent mental disorders. Noise sensitivity (NS) is considered a moderator of non-auditory noise effects. In the present study, we aimed to assess whether NS is associated with non-auditory effects. Methods We recruited a community sample of 1836 residents residing in Ulsan and Seoul...

  15. Frequently asked questions on filtered noise

    DEFF Research Database (Denmark)

    Blanke, Mogens

    This note was made in response to several returning questions on noise and ways to calculate covariance of filtered random signals, where filters could origin from residual generators. Reference is made to stochastic signals treated in appendix 2 of the book Diagnosis and Fault-tolerant Control...

  16. Low noise ICR detection electronics

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, G.A.; Bruce, J.E.; Hofstadler, S.A. [Pacific Northwest Lab., Richland, WA (United States)] [and others

    1995-12-31

    FTICR signal detection offers many challenges; both wide bandwidth and low noise performance are required. Since, the input impedance of the amplifier is a very critical parameter, optimal performance of the preamplifier involves a careful balance of input impedance and noise performance through circuit design and component selection. The FTICR cell and its connections to the preamplifier are another critical parameter in FTICR detection sensitivity. This work has investigated signal detection electronics for improved FTICR detection sensitivity. Amplifier noise sources are identified and their effect on detection sensitivity are evaluated. A high sensitivity, low noise preamplifier, developed in this laboratory, is presented and its performance is evaluated and contrasted with different preamplifier configurations. The detection circuit is analyzed and the effect of cell and wiring capacitance is discussed. The circuit sensitivity is calculated and compared with measured results. Component selection criteria are discussed and the present state-of-the-art components are evaluated. The effect of preamplifier cooling is also investigated and the results are presented. Different detection frequency ranges result in different circuit optimization; these effects are analyzed and optimal component values and circuit configurations are shown for different frequency ranges.

  17. Introduction: Unsolved Problems on Noise

    Science.gov (United States)

    Oriols, X.; Ciliberto, S.

    2016-05-01

    This paper is an introduction to the special issue of the 7th Int. Conf. on Unsolved Problems on Noise (UPoN) that took place at Casa Convalescència in Barcelona (Spain) in July 2015. The aim of the UPoN conferences is to provide a forum for researchers working on different fields of noise, fluctuations and variability, where they present their scientific problems which resist solutions. The papers of this Special Issue reflect the interdisciplinary topics (physics, biology, circuits, financial markets, psychology, technology, etc) presented at the UPoN conference. Noise is not only a hindrance to signal detection, but it is indeed a valuable source of information (not present in the signal) that help us to get a deeper understanding on how Nature works. This special issue of the 7th International Conference on Unsolved Problems on Noise (UPoN) is dedicated to Laszlo Kish in the occasion of his 60th birthday. He organized the first edition of these UPoN conferences in Szeged (Hungary) in 1996. Many of us have greatly benefited from his ‘volcanic imagination in tackling new problems from unconventional points of views’.

  18. Evaluation of noise levels in manufacturing sectors in Thika district ...

    African Journals Online (AJOL)

    Noise is considered as any unwanted sound that may adversely affect the health and wellbeing of individuals or populations exposed. This study assessed the magnitude of occupational noise exposures to workers in different manufacturing sectors in Thika District‐Kenya. Systematic random sampling was used to select 8 ...

  19. Survey of noise levels in wood workshops in Morogoro Municipal ...

    African Journals Online (AJOL)

    This study was done in wood workshops in Morogoro municipal to survey noise exposure levels and woodworkers attitudes toward noise hazards. Five woodworking shops which constitute about 17% of the registered ones were randomly selected. Sound exposure level for workers was assessed using sound level meter.

  20. Road traffic noise and children's inattention.

    Science.gov (United States)

    Weyde, Kjell Vegard; Krog, Norun Hjertager; Oftedal, Bente; Magnus, Per; Øverland, Simon; Stansfeld, Stephen; Nieuwenhuijsen, Mark J; Vrijheid, Martine; de Castro Pascual, Montserrat; Aasvang, Gunn Marit

    2017-11-21

    An increasing number of children are exposed to road traffic noise levels that may lead to adverse effects on health and daily functioning. Childhood is a period of intense growth and brain maturation, and children may therefore be especially vulnerable to road traffic noise. The objective of the present study was to examine whether road traffic noise was associated with reported inattention symptoms in children, and whether this association was mediated by sleep duration. This study was based on the Norwegian Mother and Child Cohort Study conducted by the Norwegian Institute of Public Health. Parental reports of children's inattention at age 8 were linked to modelled levels of residential road traffic noise. We investigated the association between inattention and noise exposure during pregnancy (n = 1934), noise exposure averaged over 5 years (age 3 to 8 years; n = 1384) and noise exposure at age 8 years (n = 1384), using fractional logit response models. The participants were children from Oslo, Norway. An association with inattention at age 8 years was found for road traffic noise exposure at age 8 years (coef = .0083, CI = [.0012, .0154]; 1.2% point increase in inattention score per 10 dB increase in noise level), road traffic noise exposure average for the last 5 years (coef = .0090, CI = [.0016, .0164]; 1.3% point increase/10 dB), and for pregnancy road traffic noise exposure for boys (coef = .0091, CI = [.0010, .0171]), but not girls (coef = -.0021, CI = [-.0094, .0053]). Criteria for doing mediation analyses were not fulfilled. Results indicate that road traffic noise has a negative impact on children's inattention. We found no mediation by sleep duration.

  1. Noise in restaurants: levels and mathematical model.

    Science.gov (United States)

    To, Wai Ming; Chung, Andy

    2014-01-01

    Noise affects the dining atmosphere and is an occupational hazard to restaurant service employees worldwide. This paper examines the levels of noise in dining areas during peak hours in different types of restaurants in Hong Kong SAR, China. A mathematical model that describes the noise level in a restaurant is presented. The 1-h equivalent continuous noise level (L(eq,1-h)) was measured using a Type-1 precision integral sound level meter while the occupancy density, the floor area of the dining area, and the ceiling height of each of the surveyed restaurants were recorded. It was found that the measured noise levels using Leq,1-h ranged from 67.6 to 79.3 dBA in Chinese restaurants, from 69.1 to 79.1 dBA in fast food restaurants, and from 66.7 to 82.6 dBA in Western restaurants. Results of the analysis of variance show that there were no significant differences between means of the measured noise levels among different types of restaurants. A stepwise multiple regression analysis was employed to determine the relationships between geometrical and operational parameters and the measured noise levels. Results of the regression analysis show that the measured noise levels depended on the levels of occupancy density only. By reconciling the measured noise levels and the mathematical model, it was found that people in restaurants increased their voice levels when the occupancy density increased. Nevertheless, the maximum measured hourly noise level indicated that the noise exposure experienced by restaurant service employees was below the regulated daily noise exposure value level of 85 dBA.

  2. Noise suppression via generalized-Markovian processes

    Science.gov (United States)

    Marshall, Jeffrey; Campos Venuti, Lorenzo; Zanardi, Paolo

    2017-11-01

    It is by now well established that noise itself can be useful for performing quantum information processing tasks. We present results which show how one can effectively reduce the error rate associated with a noisy quantum channel by counteracting its detrimental effects with another form of noise. In particular, we consider the effect of adding on top of a purely Markovian (Lindblad) dynamics, a more general form of dissipation, which we refer to as generalized-Markovian noise. This noise has an associated memory kernel and the resulting dynamics are described by an integrodifferential equation. The overall dynamics are characterized by decay rates which depend not only on the original dissipative time scales but also on the new integral kernel. We find that one can engineer this kernel such that the overall rate of decay is lowered by the addition of this noise term. We illustrate this technique for the case where the bare noise is described by a dephasing Pauli channel. We analytically solve this model and show that one can effectively double (or even triple) the length of the channel, while achieving the same fidelity, entanglement, and error threshold. We numerically verify this scheme can also be used to protect against thermal Markovian noise (at nonzero temperature), which models spontaneous emission and excitation processes. A physical interpretation of this scheme is discussed, whereby the added generalized-Markovian noise causes the system to become periodically decoupled from the background Markovian noise.

  3. Noise exposures in US coal mines

    Energy Technology Data Exchange (ETDEWEB)

    Seiler, J.P.; Valoski, M.P.; Crivaro, M.A.

    1994-05-01

    Mine Safety and Health Administration (MSHA) inspectors conduct full-shift environmental noise surveys to determine the occupational noise levels to which coal miners are exposed. These noise surveys are performed to determine compliance with the noise standard promulgated under the Federal Mine Safety and Health Act of 1977. Data from over 60,000 full-shift noise surveys conducted from fiscal year 1986 through 1992 were entered into a computer data base to facilitate analysis. This paper presents the mean and standard deviation of over 60,000 full-shift noise dose measurements for various underground and surface coal mining occupations. Additionally, it compares and contrasts the levels with historical noise exposure measurements for selected coal mining occupations that were published in the 1970`s. The findings were that the percentage of miners surveyed that were subjected to noise exposures above 100%, neglecting personal hearing protectors, were 26.5% and 21.6% for surface and underground mining, respectively. Generally, the trend is that the noise exposures for selected occupations have decreased since the 1970`s.

  4. Annoyance caused by aircraft en route noise

    Science.gov (United States)

    Mccurdy, David A.

    1992-01-01

    A laboratory experiment was conducted to quantify the annoyance response of people on the ground to enroute noise generated by aircraft at cruise conditions. The en route noises were ground level recordings of eight advanced turboprop aircraft flyovers and six conventional turbofan flyovers. The eight advanced turboprop enroute noises represented the NASA Propfan Test Assessment aircraft operating at different combinations of altitude, aircraft Mach number, and propeller tip speed. The conventional turbofan en route noises represented six different commercial airliners. The overall durations of the en route noises varied from approximately 40 to 160 sec. In the experiment, 32 subjects judged the annoyance of the en route noises as well as recordings of the takeoff and landing noises of each of 5 conventional turboprop and 5 conventional turbofan aircraft. Each of the noises was presented at three sound pressure levels to the subjects in an anechoic listening room. Analysis of the judgments found small differences in annoyance between three combinations of aircraft type and operation. Current tone and corrections did not significantly improve en route annoyance prediction. The optimum duration-correction magnitude for en route noise was approximately 1 dB per doubling of effective duration.

  5. Noise simulation system for determining imaging conditions in digital radiography

    Science.gov (United States)

    Tanaka, R.; Ichikawa, K.; Matsubara, K.; Kawashima, H.

    2012-03-01

    Reduction of exposure dose and improvement in image quality can be expected to result from advances in the performance of imaging detectors. We propose a computerized method for determining optimized imaging conditions by use of simulated images. This study was performed to develop a prototype system for image noise and to ensure consistency between the resulting images and actual images. An RQA5 X-ray spectrum was used for determination of input-output characteristics of a flat-panel detector (FPD). The number of incident quantum to the detector per pixel (counts/pixel) was calculated according to the pixel size of the detector and the quantum number in RQA5 determined in IEC6220-1. The relationship among tube current-time product (mAs), exposure dose (C/kg) at the detector surface, the number of incident quanta (counts/pixel), and pixel values measured on the images was addressed, and a conversion function was then created. The images obtained by the FPD was converted into a map of incident quantum numbers and input into random-value generator to simulate image noise. In addition, graphic user interface was developed to observe images with changing image noise and exposure dose levels, which have trade-off relationship. Simulation images provided at different noise levels were compared with actual images obtained by the FPD system. The results indicated that image noise was simulated properly both in objective and subjective evaluation. The present system could allow us to determine necessary dose from image quality and also to estimate image quality from any exposure dose.

  6. Effect of tinnitus masker noise on speech discrimination in quiet and two noise backgrounds.

    Science.gov (United States)

    Spitzer, J B; Goldstein, B A; Salzbrenner, L G; Mueller, G

    1983-01-01

    Use of masking devices is achieving recognition as a means of providing tinnitus relief. While palliative results have been described, possible disruptive consequences have not yet received attention. The present study examined the effects of tinnitus masker noise on speech intelligibility. Twenty young normals listened to NU-6 word lists presented in sound field in quiet white noise, and cocktail party noise backgrounds (S/N = O dB) with and without a tinnitus masker. Although there was little impairment while wearing the masker in quiet, substantial discrimination loss was observed in the two noise backgrounds. The potential disruption in communication function while wearing a masking device is discussed.

  7. Advanced Noise Abatement Procedures for a Supersonic Business Jet

    Science.gov (United States)

    Berton, Jeffrey J.; Jones, Scott M.; Seidel, Jonathan A.; Huff, Dennis L.

    2017-01-01

    Supersonic civil aircraft present a unique noise certification challenge. High specific thrust required for supersonic cruise results in high engine exhaust velocity and high levels of jet noise during takeoff. Aerodynamics of thin, low-aspect-ratio wings equipped with relatively simple flap systems deepen the challenge. Advanced noise abatement procedures have been proposed for supersonic aircraft. These procedures promise to reduce airport noise, but they may require departures from normal reference procedures defined in noise regulations. The subject of this report is a takeoff performance and noise assessment of a notional supersonic business jet. Analytical models of an airframe and a supersonic engine derived from a contemporary subsonic turbofan core are developed. These models are used to predict takeoff trajectories and noise. Results indicate advanced noise abatement takeoff procedures are helpful in reducing noise along lateral sidelines.

  8. Performance of Power Systems under Sustained Random Perturbations

    Directory of Open Access Journals (Sweden)

    Humberto Verdejo

    2014-01-01

    Full Text Available This paper studies linear systems under sustained additive random perturbations. The stable operating point of an electric power system is replaced by an attracting stationary solution if the system is subjected to (small random additive perturbations. The invariant distribution of this stationary solution gives rise to several performance indices that measure how well the system copes with the randomness. These indices are introduced, showing how they can be used for the optimal tuning of system parameters in the presence of noise. Results on a four-generator two-area system are presented and discussed.

  9. Phase noise and frequency stability in oscillators

    CERN Document Server

    Rubiola, Enrico

    2009-01-01

    Presenting a comprehensive account of oscillator phase noise and frequency stability, this practical text is both mathematically rigorous and accessible. An in-depth treatment of the noise mechanism is given, describing the oscillator as a physical system, and showing that simple general laws govern the stability of a large variety of oscillators differing in technology and frequency range. Inevitably, special attention is given to amplifiers, resonators, delay lines, feedback, and flicker (1/f) noise. The reverse engineering of oscillators based on phase-noise spectra is also covered, and end-of-chapter exercises are given. Uniquely, numerous practical examples are presented, including case studies taken from laboratory prototypes and commercial oscillators, which allow the oscillator internal design to be understood by analyzing its phase-noise spectrum. Based on tutorials given by the author at the Jet Propulsion Laboratory, international IEEE meetings, and in industry, this is a useful reference for acade...

  10. ERCB directive 038 noise impact assessment - noise monitoring follow-up approach and case study

    Energy Technology Data Exchange (ETDEWEB)

    Chui, Jonathan [Institute of Noise Control Engineering (United States)], Email: jccwmdj@gmail.com, email: jonathan.chui@auc.ab.ca; South, Don RET [Energy Resources Conservation Board (Canada)], Email: Don.South@ercb.ca; Hann, Henk de [Golder Associates Ltd. (Canada)], Email: Henk_deHaan@golder.com; Molina, Carolina [Cenovus FCCL Ltd (Canada)], Email: Carolina.Molina@cenovus.com

    2011-07-01

    In any noise impact assessment, Directive 038 of the Alberta Energy Resource Conservation Board (ERCB) recommends the use of a noise model to predict noise emission from industrial buildings, but such a model can present discrepancies relative to actual noise emissions, and these can accumulate over the different building phases of a project. This paper focuses on steam-assisted gravity drainage in Alberta, and is intended to show the advantages of taking noise measurements in-between construction phases for better continuity and fewer uncertainties in theoretical noise predictions. Short term and long term measurements, especially of low frequency noise, were taken at different locations in and around the plant and then compared with theoretical predictions, based on manufacturer specifications and in accordance with Directive 038. Differences were observed, due mainly to erroneous model assumptions. Actual noise measurements are thus a useful means to ensure continuity in a multiple-phase noise impact assessment as well as to correct discrepancies in a noise model accurately, thus reducing prediction errors for present and future projects.

  11. assessment of noise pollutio noise pollutio noise pollution

    African Journals Online (AJOL)

    eobe

    related ailments impairment (71.9%). Therefore noi impairment (71.9%). Therefore noise prevention se prevention audiometric tests, training, education, and enforcem. Keywords: Keywords: .... marketing for local consumption or transportation to the northern ..... disorders in workers as well as those living within the vicinity of ...

  12. Evaluation Of Noise Cancellation Using LMS And NLMS Algorithm

    Directory of Open Access Journals (Sweden)

    Niti Gupta

    2015-08-01

    Full Text Available This paper is focused on the adaptive noise cancellation of speech signal using the least mean square LMS and normalized least mean square method NLMS. Adaptive Noise Cancellation is an alternative way of cancelling noise present in a corrupted signal. In this technique evaluation of distorted signal by additive noise or interference achieved with no a priori estimates of signal or noise. A comparative study is carried out using LMS and NLSM methods. Result shows that these methods has potential in noise cancellation and can be used for variety of applications.

  13. Selective attention and the auditory vertex potential. 2: Effects of signal intensity and masking noise

    Science.gov (United States)

    Schwent, V. L.; Hillyard, S. A.; Galambos, R.

    1975-01-01

    A randomized sequence of tone bursts was delivered to subjects at short inter-stimulus intervals with the tones originating from one of three spatially and frequency specific channels. The subject's task was to count the tones in one of the three channels at a time, ignoring the other two, and press a button after each tenth tone. In different conditions, tones were given at high and low intensities and with or without a background white noise to mask the tones. The N sub 1 component of the auditory vertex potential was found to be larger in response to attended channel tones in relation to unattended tones. This selective enhancement of N sub 1 was minimal for loud tones presented without noise and increased markedly for the lower tone intensity and in noise added conditions.

  14. Direct parameter-extraction method for MOSFET noise model from microwave noise figure measurement

    Science.gov (United States)

    Gao, Jianjun

    2011-09-01

    A new method for the determination of the four noise parameters of the metal oxide semiconductor field effect transistors (MOSFETs) based on the noise figure measurement system without microwave tuner is presented. The noise parameters are determined based on a set of analytical expressions of noise parameters by fitting the measured noise figure of the active device. These expressions are derived from an accurate small signal and noise equivalent circuit model, which takes into account the substrate parasitics, pad capacitances, and series inductances. On-wafer experimental verification is presented and a comparison with tuner based method is given. Good agreement is obtained between simulated and measured results for 0.5 × 5 × 16 μm, 0.35 × 5 × 16 μm and 0.18 × 5 × 16 μm (gate length × number of gate fingers × unit gate width) MOSFETs.

  15. Poultry Plant Noise Control

    Science.gov (United States)

    1982-01-01

    A demonstration conducted last winter at the Tip Top Poultry Plant intended to show poultry plant managers from all over the U.S. potential solutions to the problem of plant noise. Plastic covers used over sound absorbing materials need to meet cleanability requirements, high- pressure water cleaning and other harsh maintenance procedures peculiar to the poultry processing industry. For the demonstration, Fiber Flex, Inc. manufactured and donated 750 noise panels; Owens-Corning Fiberglas Corporation donated the fiberglas cores; and the cover material was purchased from Howe and Bainbridge. The Engineering Experiment Station (EES) conducted before and after noise surveys and is evaluating the effect of noise reduction on turnover and productivity in the demonstration plant. EES plans to conduct a noise abatement workshop and update a handbook to help poultry processors with noise problems. EES study and demonstration may be applicable to other food processing plants where similar sanitary constraints exist.

  16. Changing Health Behaviors to Improve Health Outcomes after Angioplasty: A Randomized Trial of Net Present Value versus Future Value Risk Communication

    Science.gov (United States)

    Charlson, M. E.; Peterson, J. C.; Boutin-Foster, C.; Briggs, W. M.; Ogedegbe, G. G.; McCulloch, C. E.; Hollenberg, J.; Wong, C.; Allegrante, J. P.

    2008-01-01

    Patients who have undergone angioplasty experience difficulty modifying at-risk behaviors for subsequent cardiac events. The purpose of this study was to test whether an innovative approach to framing of risk, based on "net present value" economic theory, would be more effective in behavioral intervention than the standard "future value approach"…

  17. Clinical presentation and personality factors are predictors of the response to treatment in patients with functional dyspepsia; a randomized, double-blind placebo-controlled crossover study.

    Science.gov (United States)

    Holtmann, Gerald; Kutscher, Sven-Uwe; Haag, Sebastian; Langkafel, Mathias; Heuft, Gereon; Neufang-Hueber, Jutta; Goebell, Harald; Senf, Wolfgang; Talley, Nicholas J

    2004-04-01

    The role of psychological factors or symptom pattern for the response to treatment in patients with unexplained (functional) dyspepsia is unknown. We hypothesized that patients with reflux- and ulcer-like symptoms would be more likely to respond to acid-lowering therapy, while psychological disturbances would be associated with a less favorable response to treatment. Seventy-eight patients with a diagnosis of functional dyspepsia were recruited and 75 completed the trial. Patients were treated for 4 weeks in a double-blind, placebo-controlled crossover trial starting in random order with either active drug (ranitidine, 150 mg b.d.) or placebo. Every 7 days, medication was switched from active drug to placebo, or vice versa. At entry, patient characteristics were assessed utilizing a semistructured standardized interview and standardized questionnaires, and weekly intensity of symptoms was assessed utilizing a visual analogue scale. Patients with a greater reduction of the symptom score during active treatment and an overall reduction of the global symptom score by more than 50% at the end of the study period were categorized as responders. Logistic regression analysis was utilized to assess the influence of symptom type and presence of psychological disturbances on the treatment response. During treatment the symptom score decreased significantly, from 32.1 +/- 1.44 (SD) to 21.3 +/- 1.9 at the end of the trial (P < 0.001). Twenty of 75 were responders. High scores for somatization (OR, 3.6; 95% Cl, 1.2-11.4), anxiety (OR, 3.3; 95% Cl, 0.9-11.8), and reflux-like symptoms (OR, 5.3; 95% Cl, 1.7-16.7) were associated with response to treatment, while dysmotility-like symptoms were associated with an unfavorable response (OR, 0.3; 95% Cl, 0.1-0.9). Symptom pattern and psychological disturbances are independent predictors of treatment response. Patients with reflux-like symptoms and greater psychological disturbances are more likely to respond to an acid

  18. Noise at the Interface

    DEFF Research Database (Denmark)

    Prior, Andrew

    2011-01-01

    The notion of noise occupies a contested territory, in which it is framed as pollution and detritus even as it makes its opposite a possibility - noise is always defined in opposition to something else, even if this ‘other’ is not quite clear. This paper explores noise in the context of ‘the...... interface’ asking what its affordances as an idea may contribute to our understanding of interface. I draw historically on information theory in particular to initiate this exploration....

  19. Acceptable noise level

    DEFF Research Database (Denmark)

    Olsen, Steen Østergaard; Nielsen, Lars Holme; Lantz, Johannes

    2012-01-01

    The acceptable noise level (ANL) is used to quantify the amount of background noise that subjects can accept while listening to speech, and is suggested for prediction of individual hearing-aid use. The aim of this study was to assess the repeatability of the ANL measured in normal-hearing subjects...... using running Danish and non-semantic speech materials as stimuli and modulated speech-spectrum and multi-talker babble noises as competing stimuli....

  20. Hypotension and Environmental Noise: A Replication Study

    Directory of Open Access Journals (Sweden)

    Peter Lercher

    2014-08-01

    Full Text Available Up to now, traffic noise effect studies focused on hypertension as health outcome. Hypotension has not been considered as a potential health outcome although in experiments some people also responded to noise with decreases of blood pressure. Currently, the characteristics of these persons are not known and whether this down regulation of blood pressure is an experimental artifact, selection, or can also be observed in population studies is unanswered. In a cross-sectional replication study, we randomly sampled participants (age 20–75, N = 807 from circular areas (radius = 500 m around 31 noise measurement sites from four noise exposure strata (35–44, 45–54, 55–64, >64 Leq, dBA. Repeated blood pressure measurements were available for a smaller sample (N = 570. Standardized information on socio-demographics, housing, life style and health was obtained by door to door visits including anthropometric measurements. Noise and air pollution exposure was assigned by GIS based on both calculation and measurements. Reported hypotension or hypotension medication past year was the main outcome studied. Exposure-effect relationships were modeled with multiple non-linear logistic regression techniques using separate noise estimations for total, highway and rail exposure. Reported hypotension was significantly associated with rail and total noise exposure and strongly modified by weather sensitivity. Reported hypotension medication showed associations of similar size with rail and total noise exposure without effect modification by weather sensitivity. The size of the associations in the smaller sample with BMI as additional covariate was similar. Other important cofactors (sex, age, BMI, health and moderators (weather sensitivity, adjacent main roads and associated annoyance need to be considered as indispensible part of the observed relationship. This study confirms a potential new noise effect pathway and discusses potential patho

  1. A de-noising method using the improved wavelet threshold function based on noise variance estimation

    Science.gov (United States)

    Liu, Hui; Wang, Weida; Xiang, Changle; Han, Lijin; Nie, Haizhao

    2018-01-01

    The precise and efficient noise variance estimation is very important for the processing of all kinds of signals while using the wavelet transform to analyze signals and extract signal features. In view of the problem that the accuracy of traditional noise variance estimation is greatly affected by the fluctuation of noise values, this study puts forward the strategy of using the two-state Gaussian mixture model to classify the high-frequency wavelet coefficients in the minimum scale, which takes both the efficiency and accuracy into account. According to the noise variance estimation, a novel improved wavelet threshold function is proposed by combining the advantages of hard and soft threshold functions, and on the basis of the noise variance estimation algorithm and the improved wavelet threshold function, the research puts forth a novel wavelet threshold de-noising method. The method is tested and validated using random signals and bench test data of an electro-mechanical transmission system. The test results indicate that the wavelet threshold de-noising method based on the noise variance estimation shows preferable performance in processing the testing signals of the electro-mechanical transmission system: it can effectively eliminate the interference of transient signals including voltage, current, and oil pressure and maintain the dynamic characteristics of the signals favorably.

  2. WHO Environmental Noise Guidelines for the European Region: A Systematic Review on Environmental Noise and Annoyance

    Directory of Open Access Journals (Sweden)

    Rainer Guski

    2017-12-01

    Full Text Available Background: This paper describes a systematic review and meta-analyses on effects of environmental noise on annoyance. The noise sources include aircraft, road, and rail transportation noise as well as wind turbines and noise source combinations. Objectives: Update knowledge about effects of environmental noise on people living in the vicinity of noise sources. Methods: Eligible were published studies (2000–2014 providing comparable acoustical and social survey data including exposure-response functions between standard indicators of noise exposure and standard annoyance responses. The systematic literature search in 20 data bases resulted in 62 studies, of which 57 were used for quantitative meta-analyses. By means of questionnaires sent to the study authors, additional study data were obtained. Risk of bias was assessed by means of study characteristics for individual studies and by funnel plots to assess the risk of publication bias. Main Results: Tentative exposure-response relations for percent highly annoyed residents (%HA in relation to noise levels for aircraft, road, rail, wind turbine and noise source combinations are presented as well as meta-analyses of correlations between noise levels and annoyance raw scores, and the OR for increase of %HA with increasing noise levels. Quality of evidence was assessed using the GRADE terminology. The evidence of exposure-response relations between noise levels and %HA is moderate (aircraft and railway or low (road traffic and wind turbines. The evidence of correlations between noise levels and annoyance raw scores is high (aircraft and railway or moderate (road traffic and wind turbines. The evidence of ORs representing the %HA increase by a certain noise level increase is moderate (aircraft noise, moderate/high (road and railway traffic, and low (wind turbines. Strengths and Limitations: The strength of the evidence is seen in the large total sample size encompassing the included studies (e

  3. System test and noise performance studies at the ATLAS pixel detector

    Energy Technology Data Exchange (ETDEWEB)

    Weingarten, J.

    2007-09-15

    The central component of the ATLAS Inner Tracker is the pixel detector. It consists of three barrel layers and three disk-layers in the end-caps in both forward directions. The innermost barrel layer is mounted at a distance of about 5 cm from the interaction region. With its very high granularity, truly two-dimensional hit information, and fast readout it is well suited to cope with the high densities of charged tracks, expected this close to the interaction region. The huge number of readout channels necessitates a very complex services infrastructure for powering, readout and safety. After a description of the pixel detector and its services infrastructure, key results from the system test at CERN are presented. Furthermore the noise performance of the pixel detector, crucial for high tracking and vertexing efficiencies, is studied. Measurements of the single-channel random noise are presented together with studies of common mode noise and measurements of the noise occupancy using a random trigger generator. (orig.)

  4. Noise in biological circuits.

    Science.gov (United States)

    Simpson, Michael L; Cox, Chris D; Allen, Michael S; McCollum, James M; Dar, Roy D; Karig, David K; Cooke, John F

    2009-01-01

    Noise biology focuses on the sources, processing, and biological consequences of the inherent stochastic fluctuations in molecular transitions or interactions that control cellular behavior. These fluctuations are especially pronounced in small systems where the magnitudes of the fluctuations approach or exceed the mean value of the molecular population. Noise biology is an essential component of nanomedicine where the communication of information is across a boundary that separates small synthetic and biological systems that are bound by their size to reside in environments of large fluctuations. Here we review the fundamentals of the computational, analytical, and experimental approaches to noise biology. We review results that show that the competition between the benefits of low noise and those of low population has resulted in the evolution of genetic system architectures that produce an uneven distribution of stochasticity across the molecular components of cells and, in some cases, use noise to drive biological function. We review the exact and approximate approaches to gene circuit noise analysis and simulation, and review many of the key experimental results obtained using flow cytometry and time-lapse fluorescent microscopy. In addition, we consider the probative value of noise with a discussion of using measured noise properties to elucidate the structure and function of the underlying gene circuit. We conclude with a discussion of the frontiers of and significant future challenges for noise biology. (c) 2009 John Wiley & Sons, Inc.

  5. Landing gear noise attenuation

    Science.gov (United States)

    Moe, Jeffrey W. (Inventor); Whitmire, Julia (Inventor); Kwan, Hwa-Wan (Inventor); Abeysinghe, Amal (Inventor)

    2011-01-01

    A landing gear noise attenuator mitigates noise generated by airframe deployable landing gear. The noise attenuator can have a first position when the landing gear is in its deployed or down position, and a second position when the landing gear is in its up or stowed position. The noise attenuator may be an inflatable fairing that does not compromise limited space constraints associated with landing gear retraction and stowage. A truck fairing mounted under a truck beam can have a compliant edge to allow for non-destructive impingement of a deflected fire during certain conditions.

  6. Effects of fluid resuscitation with colloids vs crystalloids on mortality in critically ill patients presenting with hypovolemic shock: the CRISTAL randomized trial.

    Science.gov (United States)

    Annane, Djillali; Siami, Shidasp; Jaber, Samir; Martin, Claude; Elatrous, Souheil; Declère, Adrien Descorps; Preiser, Jean Charles; Outin, Hervé; Troché, Gilles; Charpentier, Claire; Trouillet, Jean Louis; Kimmoun, Antoine; Forceville, Xavier; Darmon, Michael; Lesur, Olivier; Reignier, Jean; Régnier, Jean; Abroug, Fékri; Berger, Philippe; Clec'h, Christophe; Cle'h, Christophe; Cousson, Joël; Thibault, Laure; Chevret, Sylvie

    2013-11-06

    Evidence supporting the choice of intravenous colloid vs crystalloid solutions for management of hypovolemic shock remains unclear. To test whether use of colloids compared with crystalloids for fluid resuscitation alters mortality in patients admitted to the intensive care unit (ICU) with hypovolemic shock. A multicenter, randomized clinical trial stratified by case mix (sepsis, trauma, or hypovolemic shock without sepsis or trauma). Therapy in the Colloids Versus Crystalloids for the Resuscitation of the Critically Ill (CRISTAL) trial was open label but outcome assessment was blinded to treatment assignment. Recruitment began in February 2003 and ended in August 2012 of 2857 sequential ICU patients treated at 57 ICUs in France, Belgium, North Africa, and Canada; follow-up ended in November 2012. Colloids (n = 1414; gelatins, dextrans, hydroxyethyl starches, or 4% or 20% of albumin) or crystalloids (n = 1443; isotonic or hypertonic saline or Ringer lactate solution) for all fluid interventions other than fluid maintenance throughout the ICU stay. The primary outcome was death within 28 days. Secondary outcomes included 90-day mortality; and days alive and not receiving renal replacement therapy, mechanical ventilation, or vasopressor therapy. Within 28 days, there were 359 deaths (25.4%) in colloids group vs 390 deaths (27.0%) in crystalloids group (relative risk [RR], 0.96 [95% CI, 0.88 to 1.04]; P = .26). Within 90 days, there were 434 deaths (30.7%) in colloids group vs 493 deaths (34.2%) in crystalloids group (RR, 0.92 [95% CI, 0.86 to 0.99]; P = .03). Renal replacement therapy was used in 156 (11.0%) in colloids group vs 181 (12.5%) in crystalloids group (RR, 0.93 [95% CI, 0.83 to 1.03]; P = .19). There were more days alive without mechanical ventilation in the colloids group vs the crystalloids group by 7 days (mean: 2.1 vs 1.8 days, respectively; mean difference, 0.30 [95% CI, 0.09 to 0.48] days; P = .01) and by 28 days (mean: 14

  7. Validation of an Aero-Acoustic Wind Turbine Noise Model Using Advanced Noise Source Measurements of a 500kW Turbine

    DEFF Research Database (Denmark)

    Bertagnolio, Franck; Aagaard Madsen, Helge; Fischer, Andreas

    2016-01-01

    rotor noise model is presented. It includes the main sources of aeroacoustic noise from wind turbines: turbulent inflow, trailing edge and stall noise. The noise measured by one microphone located directly downstream of the wind turbine is compared to the model predictions at the microphone location....... A good qualitative agreement is found. When wind speed increases, the rotor noise model shows that at high frequencies the stall noise becomes dominant. It also shows that turbulent inflow noise is dominant at low frequencies for all wind speeds and that trailing edge noise is dominant at low wind speeds...

  8. Envelope-based inter-aural time difference localization training to improve speech-in-noise perception in the elderly.

    Science.gov (United States)

    Delphi, Maryam; Lotfi, Yones; Moossavi, Abdollah; Bakhshi, Enayatollah; Banimostafa, Maryam

    2017-01-01

    Background: Many elderly individuals complain of difficulty in understanding speech in noise despite having normal hearing thresholds. According to previous studies, auditory training leads to improvement in speech-in-noise perception, but these studies did not consider the etiology, so their results cannot be generalized. The present study aimed at investigating the effectiveness of envelopebased interaural time difference (ITD ENV) localization training on improving ITD threshold and speech-in-noise perception. Methods: Thirty-two elderly males aged 55 to 65 years with clinically diagnosed normal hearing at 250-2000 Hertz, who suffered from speech-in-noise perception difficulty participated in this study. These individuals were randomly divided into training and control groups: 16 elderlies in the experimental group received envelope-based interaural time difference localization training in 9 sessions, but 16 matched elderlies in the control group did not receive any training. The ITD ENV threshold and spatial word recognition score (WRS) in noise were analyzed before and after the localization training. Results: Findings demonstrated that following the training program, the interaural time difference envelope threshold and spatial word recognition score (WRS) in noise were improved significantly in the experimental group (p≤ 0.001). Moreover, a significant difference was detected in interaural time difference envelope threshold and spatial word recognition score (WRS) in noise (p≤ 0.001) before and after the training in the experimental group. Conclusion: The results of the present study revealed the effectiveness of envelope- based interaural time difference localization training in localization ability and speech in noise perception in the elderlies with normal hearing up to 2000 Hz who suffered from speech-in-noise perception difficulty.

  9. Flux Noise in a Superconducting Transmission Line

    Science.gov (United States)

    Vasko, F. T.

    2017-08-01

    We study a superconducting transmission line (TL) formed by distributed L C oscillators and excited by external magnetic fluxes which are aroused from random magnetization (A ) placed in substrate or (B ) distributed at interfaces of a two-wire TL. The low-frequency dynamics of a random magnetic field is described based on the diffusion Langevin equation with a short-range source caused by (a ) a random amplitude or (b ) the gradient of magnetization. For a TL modeled as a two-port network with open and shorted ends, the effective magnetic flux at the open end has nonlocal dependency on noise distribution along the TL. The flux-flux correlation function is evaluated and analyzed for the regimes (A a ), (A b ), (B a ), and (B b ). Essential frequency dispersion takes place around the inverse diffusion time of random flux along the TL. Typically, noise effect increases with size faster than the area of the TL. The flux-flux correlator can be verified both via the population relaxation rate of the qubit, which is formed by the Josephson junction shunted by the TL with flux noises, and via random voltage at the open end of the TL.

  10. Noise minimization in eukaryotic gene expression

    Energy Technology Data Exchange (ETDEWEB)

    Fraser, Hunter B.; Hirsh, Aaron E.; Giaever, Guri; Kumm, Jochen; Eisen, Michael B.

    2004-01-15

    All organisms have elaborate mechanisms to control rates of protein production. However, protein production is also subject to stochastic fluctuations, or noise. Several recent studies in Saccharomyces cerevisiae and Escherichia coli have investigated the relationship between transcription and translation rates and stochastic fluctuations in protein levels, or more generally, how such randomness is a function of intrinsic and extrinsic factors. However, the fundamental question of whether stochasticity in protein expression is generally biologically relevant has not been addressed, and it remains unknown whether random noise in the protein production rate of most genes significantly affects the fitness of any organism. We propose that organisms should be particularly sensitive to variation in the protein levels of two classes of genes: genes whose deletion is lethal to the organism and genes that encode subunits of multiprotein complexes. Using an experimentally verified model of stochastic gene expression in S. cerevisiae, we estimate the noise in protein production for nearly every yeast gene, and confirm our prediction that the production of essential and complex-forming proteins involves lower levels of noise than does the production of most other genes. Our results support the hypothesis that noise in gene expression is a biologically important variable, is generally detrimental to organismal fitness, and is subject to natural selection.

  11. Noise as environment al pollution – medical aspects

    Directory of Open Access Journals (Sweden)

    Krystyna Pawlas

    2015-12-01

    Full Text Available Noise is ubiquitous in human environment. Paper presents current knowledge on extra- aural health effects of exposure to environmental noise. noise is not solely annoyance, but more and moreresearches show that this pollution is a risk factor for different health disorders: sleep, hypertension, cardiovascular diseases and others that challenge for public health. Moreover it has social and economical dimensions.

  12. Noise as environment al pollution – medical aspects

    OpenAIRE

    Krystyna Pawlas

    2015-01-01

    Noise is ubiquitous in human environment. Paper presents current knowledge on extra- aural health effects of exposure to environmental noise. noise is not solely annoyance, but more and moreresearches show that this pollution is a risk factor for different health disorders: sleep, hypertension, cardiovascular diseases and others that challenge for public health. Moreover it has social and economical dimensions.

  13. The role of noise sensitivity in the noise-response relation: A comparison of three international airport studies

    Science.gov (United States)

    van Kamp, Irene; Job, R. F. Soames; Hatfield, Julie; Haines, Mary; Stellato, Rebecca K.; Stansfeld, Stephen A.

    2004-12-01

    In order to examine the role of noise sensitivity in response to environmental noise, this paper presents detailed comparisons of socio-acoustic studies conducted around international airports in Amsterdam, Sydney, and London. Earlier findings that noise sensitivity moderates the effect of noise on annoyance were examined to see if they could be replicated in each of the datasets, independent of the technique of measuring noise sensitivity. The relation between exposure to aircraft noise and noise annoyance was studied separately for groups of individuals with low, medium, and high noise sensitivity, with statistical adjustment for relevant confounders. Results support the previous findings that noise sensitivity is an independent predictor of annoyance and adds to the prediction of noise annoyance afforded by noise exposure level by up to 26% of explained variance. There is no evidence of a moderating effect, whereby the covariation between noise exposure level and annoyance is weak for people who score at the extreme high or low end of the sensitivity scale, and strong for people who score in the middle of the sensitivity scale. Generally, noise sensitivity appears to increase annoyance independently of the level of noise exposure after adjustment for relevant confounders. These findings were consistent across the three datasets. .

  14. Investigation of Noise in Electronic Ultrasonic Systems

    Directory of Open Access Journals (Sweden)

    Paulius Adomavičius

    2011-03-01

    Full Text Available Noise models in ultrasonic control system have been investigated. Ultrasonic system channel consist of exciting generator, ultrasonic transducer, amplitude limiter, amplifier, low band filter and A/D converter. The ultrasonic transducers have been described as Von Hippel model, Van Dyke model or improved Van Dyke model. Advantages and disadvantages of these models are discussed in this paper. Noise models of amplitude limiter and linear operational amplifier are presented. The summary results of calculated noise spectral density of ultrasonic system channel have been presented.Article in Lithuanian

  15. Adaptive tight frame based multiplicative noise removal

    National Research Council Canada - National Science Library

    Weifeng Zhou; Shuguo Yang; Caiming Zhang; Shujun Fu

    2016-01-01

    .... However, it is impossible for a fixed system to be always optimal for all the images. In this paper, we present an adaptive wavelet tight frame technology for sparse representation of an image with multiplicative noise...

  16. Adaptive tight frame based multiplicative noise removal

    National Research Council Canada - National Science Library

    Allikalt, Anni; Zhou, Weifeng; Rinken, Ago; Yang, Shuguo; Zhang, Caiming; Fu, Shujun

    .... However, it is impossible for a fixed system to be always optimal for all the images. In this paper, we present an adaptive wavelet tight frame technology for sparse representation of an image with multiplicative noise...

  17. Characterization of noise in different industrial workstations

    Science.gov (United States)

    Correia, Aldina; Lopes, Miguel; de Almeida, M. Fátima

    2017-11-01

    The damage caused by noise in workers' health is well known. The European Agency for Safety and Health at Work presented in 2005 a summary of main effects of workplace noise, defining the loss of hearing as the principal effect of noise exposure, however, it can also exacerbate stress and increase the risk of accidents. The problem to be addressed is this work is about noise analysis, performed under the PREVENIR program. The data was collected in industrial workplaces from 280 Portuguese industrial companies distributed by different sectors. The program was implemented between 2005 and 2011. The aim of this work is identify differences of intensity of noise exposure between these industrial sectors in different workplaces, using inference techniques. The existence of significance differences between average levels of Equivalent Sound Level (LAeq,TdB(A)) are verified using ANOVA.

  18. Noise-driven phenomena in hysteretic systems

    CERN Document Server

    Dimian, Mihai

    2014-01-01

    Noise-Driven Phenomena in Hysteretic Systems provides a general approach to nonlinear systems with hysteresis driven by noisy inputs, which leads to a unitary framework for the analysis of various stochastic aspects of hysteresis. This book includes integral, differential and algebraic models that are used to describe scalar and vector hysteretic nonlinearities originating from various areas of science and engineering. The universality of the authors approach is also reflected by the diversity of the models used to portray the input noise, from the classical Gaussian white noise to its impulsive forms, often encountered in economics and biological systems, and pink noise, ubiquitous in multi-stable electronic systems. The book is accompanied by HysterSoft© - a robust simulation environment designed to perform complex hysteresis modeling – that can be used by the reader to reproduce many of the results presented in the book as well as to research both disruptive and constructive effects of noise in hysteret...

  19. Ocean Ambient Noise Measurement and Theory

    CERN Document Server

    Carey, William M

    2011-01-01

    This book develops the theory of ocean ambient noise mechanisms and measurements, and also describes general noise characteristics and computational methods.  It concisely summarizes the vast ambient noise literature using theory combined with key representative results.  The air-sea boundary interaction zone is described in terms of non-dimensional variables requisite for future experiments.  Noise field coherency, rare directional measurements, and unique basin scale computations and methods are presented.  The use of satellite measurements in these basin scale models is demonstrated.  Finally, this book provides a series of appendices giving in-depth mathematical treatments.  With its complete and careful discussions of both theory and experimental results, this book will be of the greatest interest to graduate students and active researchers working in fields related to ambient noise in the ocean.

  20. Improving the Accuracy of Smart Devices to Measure Noise Exposure

    OpenAIRE

    Roberts, Benjamin; Kardous, Chucri; Neitzel, Richard

    2016-01-01

    Occupational noise exposure is one of the most frequent hazards present in the workplace; up to 22 million workers have potentially hazardous noise exposures in the US. As a result, noise-induced hearing loss is one of the most common occupational injuries in the United States. Workers in manufacturing, construction, and the military are at the highest risk for hearing loss. Despite the large number of people exposed to high levels of noise at work, many occupations have not been adequately e...

  1. SIMULATION AND PERFORMANCE ANALYASIS OF ADAPTIVE FILTER IN NOISE CANCELLATION

    OpenAIRE

    RAJ KUMAR THENUA,; S.K. AGARWAL

    2010-01-01

    Noise problems in the environment have gained attention due to the tremendous growth of technology that has led to noisy engines, heavy machinery, high speed wind buffeting and other noise sources. The problem of controlling the noise level has become the focus of a tremendous amount of research over the years. In last few years various adaptive algorithms are developed for noise cancellation. In this paper we present an implementation of LMS (Least Mean Square), NLMS (Normalized Least Mean S...

  2. Collaborative noise data collected from smartphones.

    Science.gov (United States)

    Bocher, Erwan; Petit, Gwendall; Picaut, Judicaël; Fortin, Nicolas; Guillaume, Gwenaël

    2017-10-01

    Noise stands for an important human health and environmental issue. Indeed, noise causes annoyance and fatigue, interferes with communication and sleep, damages hearing and entails cardiovascular problems (WHO, 2011) [1]. From an environmental point of view, noise implies a lessening of both the richness and abundance of the animal species, an alteration of the communication, which can threaten the reproduction and predation, etc. (Newport et al., 2014; Shannon et al., 2014) [2], [3]. Consequently, effects related to environmental noise result in a huge cost for society, with 2.2 billion euros in France, for example, for the year 2013 (Bourges and Diel, 2015) [4]. In this context, the reduction of noise in the environment is a burning issue, which requires, firstly, carrying out an evaluation of noise in the environment, and secondly, to establish action plans to reduce noise annoyance. With the development of the concept of participatory measurement, and considering the extremely large number of people equipped with a smartphone while being "in mobility", the use of smartphones is potentially a relevant solution to realize a large-scale environmental noise evaluation. The data presented hereinafter are collected from the Android NoiseCapture application and shared from the OnoMap Spatial Data Infrastructure (SDI). The NoiseCapture approach consists in measuring noise along a path, and then to share data with the community. This approach has been developed within the framework of the European ENERGIC-OD project, which aims at deploying a set of Virtual Hubs (VH) to share heterogeneous data with third parties, in respect with the European INSPIRE, and at developing new and original services that can be useful for the community. The noise data that are acquired by volunteers around the world (citizen observations), are organized in three files, containing the path of measures (a set of points), standardized noise indicators, noise description and other useful

  3. Noise in miniature microphones.

    Science.gov (United States)

    Thompson, Stephen C; LoPresti, Janice L; Ring, Eugene M; Nepomuceno, Henry G; Beard, John J; Ballad, William J; Carlson, Elmer V

    2002-02-01

    The internal noise spectrum in miniature electret microphones of the type used in the manufacture of hearing aids is measured. An analogous circuit model of the microphone is empirically fit to the measured data and used to determine the important sources of noise within the microphone. The dominant noise source is found to depend on the frequency. Below 40 Hz and above 9 kHz, the dominant source is electrical noise from the amplifier circuit needed to buffer the electrical signal from the microphone diaphragm. Between approximately 40 Hz and 1 kHz, the dominant source is thermal noise originating in the acoustic flow resistance of the small hole pierced in the diaphragm to equalize barometric pressure. Between approximately 1 kHz and 9 kHz, the noise originates in the acoustic flow resistances of sound entering the microphone and propagating to the diaphragm. To further reduce the microphone internal noise in the audio band requires attacking these sources. A prototype microphone having reduced acoustical noise is measured and discussed.

  4. Mediality is Noise

    DEFF Research Database (Denmark)

    Prior, Andrew

    This PhD is concerned with the use of noise as a material within media arts practice, especially in ‘post-digital’ contexts such as glitch electronica, glitch art and uses of old media. It examines the relationship between informational culture and noise, exploring the ways in which the structuring...

  5. Acceptable noise level

    DEFF Research Database (Denmark)

    Olsen, Steen Østergaard; Nielsen, Lars Holme; Lantz, Johannes

    2012-01-01

    The acceptable noise level (ANL) is used to quantify the amount of background noise that subjects can accept while listening to speech, and is suggested for prediction of individual hearing-aid use. The aim of this study was to assess the repeatability of the ANL measured in normal-hearing subjec...

  6. Signal-to-Noise Ratio Analysis of a Phase-Sensitive Voltmeter for Electrical Impedance Tomography.

    Science.gov (United States)

    Murphy, Ethan K; Takhti, Mohammad; Skinner, Joseph; Halter, Ryan J; Odame, Kofi

    2017-04-01

    In this paper, thorough analysis along with mathematical derivations of the matched filter for a voltmeter used in electrical impedance tomography systems are presented. The effect of the random noise in the system prior to the matched filter, generated by other components, are considered. Employing the presented equations allow system/circuit designers to find the maximum tolerable noise prior to the matched filter that leads to the target signal-to-noise ratio (SNR) of the voltmeter, without having to over-design internal components. A practical model was developed that should fall within 2 dB and 5 dB of the median SNR measurements of signal amplitude and phase, respectively. In order to validate our claims, simulation and experimental measurements have been performed with an analog-to-digital converter (ADC) followed by a digital matched filter, while the noise of the whole system was modeled as the input referred at the ADC input. The input signal was contaminated by a known value of additive white Gaussian noise (AWGN) noise, and the noise level was swept from 3% to 75% of the least significant bit (LSB) of the ADC. Differences between experimental and both simulated and analytical SNR values were less than 0.59 and 0.35 dB for RMS values ≥ 20% of an LSB and less than 1.45 and 2.58 dB for RMS values circuit designers in EIT, and a more accurate error analysis that was previously missing in EIT literature.

  7. Noise levels associated with urban land use.

    Science.gov (United States)

    King, Gavin; Roland-Mieszkowski, Marek; Jason, Timothy; Rainham, Daniel G

    2012-12-01

    Recent trends towards the intensification of urban development to increase urban densities and avoid sprawl should be accompanied by research into the potential for related health impacts from environmental exposure. The objective of the current study was to examine the effect of the built environment and land use on levels of environmental noise. Two different study areas were selected using a combination of small area census geography, land use information, air photography, and ground-truthing. The first study area represented residential land use and consisted of two- to three-story single-family homes. The second study area was characteristic of mixed-use urban planning with apartment buildings as well as commercial and institutional development. Study areas were subdivided into six grids, and a location was randomly selected within each grid for noise monitoring. Each location was sampled four times over a 24-h day, resulting in a total of 24 samples for each of the two areas. Results showed significant variability in noise within study areas and significantly higher levels of environmental noise in the mixed-use area. Both study areas exceeded recommended noise limits when evaluated against World Health Organization guidelines and yielded average noise events values in the moderate to serious annoyance range with the potential to obscure normal conversation and cause sleep disturbance.

  8. Study of 1/f noise in solids

    Science.gov (United States)

    Vanvliet, K. M.; Chenette, E. R.

    1981-05-01

    A Hewlett-Packard digital fast Fourier transform spectral analyser was purchased and adapted for our purpose by writing several computer programs for the output display. Test jigs for devices under test and preamplifiers were built. Further, a real time dual channel correlation spectral analyzer was designed and partially built. Measurements involving temperature fluctuations and correlations in metal films and in integrated circuit transistors are described. The latter have been recently completed. It is conclusively shown that temperature fluctuations are not the cause of 1/f noise in these devices. Under the heading of theoretical work, an extensive analysis is presented of noise in diffusion systems. Several analytical models, not considered before, have been solved and the noise is presented. It is conclusively shown that volume (bulk) diffusion noise, whether based on the physical diffusion source or on Voss and Clarke's P-source, never leads to 1/f-type spectra. However, surface fluctuations as, e.g., caused by stochastic surface generation-recombination processes, can give rise to many decades of 1/f noise. This is worked out in detail for a MOSFET structure. We conclude, therefore, that the large noise observed in MOSFETs can be due to carrier number fluctuations subject to diffusion; at low frequencies the MacWhorter-van der Ziel model may be operative, whereas at higher frequencies our model takes over. Finally, in the theory section we present a novel derivation of quantum 1/f noise, occurring in emission processes.

  9. Personal and situational variables associated with wind turbine noise annoyance.

    Science.gov (United States)

    Michaud, David S; Keith, Stephen E; Feder, Katya; Voicescu, Sonia A; Marro, Leonora; Than, John; Guay, Mireille; Bower, Tara; Denning, Allison; Lavigne, Eric; Whelan, Chantal; Janssen, Sabine A; Leroux, Tony; van den Berg, Frits

    2016-03-01

    The possibility that wind turbine noise (WTN) affects human health remains controversial. The current analysis presents results related to WTN annoyance reported by randomly selected participants (606 males, 632 females), aged 18-79, living between 0.25 and 11.22 km from wind turbines. WTN levels reached 46 dB, and for each 5 dB increase in WTN levels, the odds of reporting to be either very or extremely (i.e., highly) annoyed increased by 2.60 [95% confidence interval: (1.92, 3.58), p wind turbine-related annoyances, personal benefit, noise sensitivity, physical safety concerns, property ownership, and province. Annoyance was related to several reported measures of health and well-being, although these associations were statistically weak (R(2 )< 9%), independent of WTN levels, and not retained in multiple regression models. The role of community tolerance level as a complement and/or an alternative to multiple regression in predicting the prevalence of WTN annoyance is also provided. The analysis suggests that communities are between 11 and 26 dB less tolerant of WTN than of other transportation noise sources.

  10. MOSFET LF noise under Large Signal Excitation: Measurement, Modelling and Application

    NARCIS (Netherlands)

    van der Wel, A.P.

    2005-01-01

    Regarding LF noise in MOSFETs, it is noted that the MOSFET is a surface channel device. Both n and p-channel devices exhibit similar low frequency (LF) noise behaviour that can be explained by a carrier number fluctuation model (section 3.5). LF noise in MOSFETs is predominantly caused by Random

  11. Modelling Urban Noise in Citygml Ade: Case of the Netherlands

    Science.gov (United States)

    Kumar, K.; Ledoux, H.; Commandeur, T. J. F.; Stoter, J. E.

    2017-10-01

    Road traffic and industrial noise has become a major source of discomfort and annoyance among the residents in urban areas. More than 44 % of the EU population is regularly exposed to road traffic noise levels over 55 dB, which is currently the maximum accepted value prescribed by the Environmental Noise Directive for road traffic noise. With continuously increasing population and number of motor vehicles and industries, it is very unlikely to hope for noise levels to diminish in the near future. Therefore, it is necessary to monitor urban noise, so as to make mitigation plans and to deal with its adverse effects. The 2002/49/EC Environmental Noise Directive aims to determine the exposure of an individual to environmental noise through noise mapping. One of the most important steps in noise mapping is the creation of input data for simulation. At present, it is done semi-automatically (and sometimes even manually) by different companies in different ways and is very time consuming and can lead to errors in the data. In this paper, we present our approach for automatically creating input data for noise simulations. Secondly, we focus on using 3D city models for presenting the results of simulation for the noise arising from road traffic and industrial activities in urban areas. We implemented a few noise modelling standards for industrial and road traffic noise in CityGML by extending the existing Noise ADE with new objects and attributes. This research is a steping stone in the direction of standardising the input and output data for noise studies and for reconstructing the 3D data accordingly.

  12. Noise properties of the Planck-LFI receivers

    Energy Technology Data Exchange (ETDEWEB)

    Meinhold, P; Leonardi, R [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Aja, B; Artal, E; Fuente, M L de la [Departamento de Ingenieria de Comunicaciones, Universidad de Cantabria, Avenida Los Castros s/n. 39005, Santander (Spain); Battaglia, P; Franceschet, C [Thales Alenia Space Italia S.p.A., IUEL - Scientific Instruments, S.S. Padana Superiore 290, 20090 Vimodrone Milano (Italy); Bersanelli, M [Universita degli Studi di Milano, Dipartamento di Fisica, via Celoria 16, 20133, Milano (Italy); Blackhurst, E; Davis, R [Jodrell Bank Centre for Astrophysics, Alan Turing Building, The University of Manchester, Manchester, M13 9PL (United Kingdom); Butler, C R; Cuttaia, F; Franceschi, E [INAF/IASF, via P. Gobetti 101, 40129 Bologna (Italy); Cuevas, L P [ESTEC, Keplerlaan 1, Postbus 299 2200 AG Noordwijk (Netherlands); D' Arcangelo, O [Istituto di Fisica del Plasma CNR, via Cozzi 53, 20125 Milan (Italy); Frailis, M; Galeotta, S [INAF/OATs, via Tiepolo, 11, 34143 Trieste (Italy); Gaier, T [Jet Propulsion Laboratory, Pasadena, CA 91109 (United States); Gregorio, A [University of Trieste, Department of Physics, via Valerio 2, 34127 Trieste (Italy); Hoyland, R, E-mail: peterm@cfi.ucsb.ed [Instituto de AstrofIsica de Canarias, C/ VIa Lactea S/N, E-38200, La Laguna, Tenerife (Spain)

    2009-12-15

    The Planck Low Frequency Instrument (LFI) radiometers have been tested extensively during several dedicated campaigns. The present paper reports the principal noise properties of the LFI radiometers. A brief description of the LFI radiometers is given along with details of the test campaigns relevant to determination of noise properties. Current estimates of flight sensitivities, 1/f parameters, and noise effective bandwidths are presented. The LFI receivers exhibit exceptional 1/f noise, and their white noise performance is sufficient for the science goals of Planck.

  13. Environmental Noise as an Operative Stressor During Simulated Laparoscopic Surgery.

    Science.gov (United States)

    Waterland, Peter; Khan, Faisal S; Ismaili, Elgerta; Cheruvu, Chandra

    2016-04-01

    This study aimed to determine what effect environmental noise has upon the psychological and physiological stress response of medical students during simulated laparoscopic surgery. An anonymous cohort of medical students were randomized into 2 arms and performed a laparoscopic task on a simulator. The "control" group performed the task in silence, whereas the "noise" group were exposed to an 80 dB verbal recording. Operator stress response was measured using a validated acute stress questionnaire and continuous heart rate (HR). A total of 70 medical students participated. The "state" component of the State Trait Anxiety Inventory questionnaire increased significantly following the task in both groups with globally higher scores recorded in the noise group. Peak-resting HR values were significantly higher in the noise group. Mean-resting HR was significantly higher in the noise group. Environmental noise in a simulated theater environment generates a measurable increase in operator stress response during laparoscopy.

  14. Perceived and actual noise levels in critical care units.

    Science.gov (United States)

    White, Brittany Lynn; Zomorodi, Meg

    2017-02-01

    To compare the noise levels perceived by critical care nurses in the Intensive Care Unit (ICU) to actual noise levels in the ICU. Following a pilot study (n=18) and revision of the survey tool, a random sample of nurses were surveyed twice in a 3-day period (n=108). Nurses perception of noise was compared to the actual sound pressure level using descriptive statistics. Nurses perceived the ICUs to be noisier than the actual values. The ICU was louder than the recommended noise level for resotrative sleep. This finding raises the question of how we can assist nurses to reduce what they perceive to be a loud environment. Future work is needed to develop interventions specifically for nurses to raise awareness of noise in the ICU and to provide them with skills to assist in noise reduction. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Measurement with verification of stationary signals and noise in extremely quiet environments: Measuring below the noise floor

    Science.gov (United States)

    Ellingson, Roger M.; Gallun, Frederick J.; Bock, Guillaume

    2015-01-01

    It can be problematic to measure stationary acoustic sound pressure level in any environment when the target level approaches or lies below the minimum measureable sound pressure level of the measurement system itself. This minimum measureable level, referred to as the inherent measurement system noise floor, is generally established by noise emission characteristics of measurement system components such as microphones, preamplifiers, and other system circuitry. In this paper, methods are presented and shown accurate measuring stationary levels within 20 dB above and below this system noise floor. Methodology includes (1) measuring inherent measurement system noise, (2) subtractive energy based, inherent noise adjustment of levels affected by system noise floor, and (3) verifying accuracy of inherent noise adjustment technique. While generalizable to other purposes, the techniques presented here were specifically developed to quantify ambient noise levels in very quiet rooms used to evaluate free-field human hearing thresholds. Results obtained applying the methods to objectively measure and verify the ambient noise level in an extremely quiet room, using various measurement system noise floors and analysis bandwidths, are presented and discussed. The verified results demonstrate the adjustment method can accurately extend measurement range to 20 dB below the measurement system noise floor, and how measurement system frequency bandwidth can affect accuracy of reported noise levels. PMID:25786932

  16. An analytical formulation for phase noise in MEMS oscillators.

    Science.gov (United States)

    Agrawal, Deepak; Seshia, Ashwin

    2014-12-01

    In recent years, there has been much interest in the design of low-noise MEMS oscillators. This paper presents a new analytical formulation for noise in a MEMS oscillator encompassing essential resonator and amplifier nonlinearities. The analytical expression for oscillator noise is derived by solving a second-order nonlinear stochastic differential equation. This approach is applied to noise modeling of an electrostatically addressed MEMS resonator-based square-wave oscillator in which the resonator and oscillator circuit nonlinearities are integrated into a single modeling framework. By considering the resulting amplitude and phase relations, we derive additional noise terms resulting from resonator nonlinearities. The phase diffusion of an oscillator is studied and the phase diffusion coefficient is proposed as a metric for noise optimization. The proposed nonlinear phase noise model provides analytical insight into the underlying physics and a pathway toward the design optimization for low-noise MEMS oscillators.

  17. Noise analysis for CCD-based ultraviolet and visible spectrophotometry.

    Science.gov (United States)

    Davenport, John J; Hodgkinson, Jane; Saffell, John R; Tatam, Ralph P

    2015-09-20

    We present the results of a detailed analysis of the noise behavior of two CCD spectrometers in common use, an AvaSpec-3648 CCD UV spectrometer and an Ocean Optics S2000 Vis spectrometer. Light sources used include a deuterium UV/Vis lamp and UV and visible LEDs. Common noise phenomena include source fluctuation noise, photoresponse nonuniformity, dark current noise, fixed pattern noise, and read noise. These were identified and characterized by varying light source, spectrometer settings, or temperature. A number of noise-limiting techniques are proposed, demonstrating a best-case spectroscopic noise equivalent absorbance of 3.5×10(-4)  AU for the AvaSpec-3648 and 5.6×10(-4)  AU for the Ocean Optics S2000 over a 30 s integration period. These techniques can be used on other CCD spectrometers to optimize performance.

  18. Evaluation of noise environments during daily activities of university students.

    Science.gov (United States)

    Tristán Hernández, Edgar; Pavón García, Ignacio; López Navarro, Juan Manuel; Kolosovas-Machuca, Eleazar Samuel

    2016-01-01

    Noise conditions specifically in areas inside university facilities and its impact on the quality of life of university students are topics that have received little attention. This paper presents a study of the noise conditions in which university students of various institutions in Madrid, Spain, carry out their daily studies. A representative number of measurements was carried out using noise dosemeters and dataloggers in order to evaluate the levels of noise, noise dose and exposure to noise during school periods and extracurricular activities. The results were compared with the recommendations given by current environmental noise regulations. This paper was complemented with a survey to get to know how students perceive the exposure to noise in university environments.

  19. Simulation-Based Prediction of Equivalent Continuous Noises during Construction Processes

    Directory of Open Access Journals (Sweden)

    Hong Zhang

    2016-08-01

    Full Text Available Quantitative prediction of construction noise is crucial to evaluate construction plans to help make decisions to address noise levels. Considering limitations of existing methods for measuring or predicting the construction noise and particularly the equivalent continuous noise level over a period of time, this paper presents a discrete-event simulation method for predicting the construction noise in terms of equivalent continuous level. The noise-calculating models regarding synchronization, propagation and equivalent continuous level are presented. The simulation framework for modeling the noise-affected factors and calculating the equivalent continuous noise by incorporating the noise-calculating models into simulation strategy is proposed. An application study is presented to demonstrate and justify the proposed simulation method in predicting the equivalent continuous noise during construction. The study contributes to provision of a simulation methodology to quantitatively predict the equivalent continuous noise of construction by considering the relevant uncertainties, dynamics and interactions.

  20. Low Noise Results From IMS Site Surveys: A Preliminary New High-Frequency Low Noise Model

    Science.gov (United States)

    Ebeling, C.; Astiz, L.; Starovoit, Y.; Tavener, N.; Perez, G.; Given, H. K.; Barrientos, S.; Yamamoto, M.; Hfaiedh, M.; Stewart, R.; Estabrook, C.

    2002-12-01

    Since the establishment of the Provisional Technical Secretariat (PTS) of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) Organization, a vigorous seismic site survey program has been carried out to identify locations as necessary for International Monitoring System (IMS) primary and auxiliary seismic stations listed in Annex 1 to the Protocol to the CTBT. The IMS Seismic Section maintains for this purpose a small pool of seismic equipment comprised of Guralp CMG-3T and CMG-3ESP and Streckeisen STS-2 broadband seismometers, and Reftek and Guralp acquisition systems. Seismic site surveys are carried out by conducting continuous measurements of ground motion at temporary installations for approximately five to seven days. Seismometer installation methods, which depend on instrument type and on local conditions, range from placement within small cement-floored subsurface vaults to near-surface burial. Data are sampled at 40 Hz. Seismic noise levels are evaluated through the analysis of power spectral density distributions. Eleven 10.5-minute-long representative de-trended and mean-removed segments each of daytime and night-time data are chosen randomly, but reviewed to avoid event contamination. Fast Fourier Transforms are calculated for the five windows in each of these segments generated using a 50% overlap for Hanning-tapered sections ~200 s long. Instrument responses are removed. To date, 20 site surveys for primary and auxiliary stations have been carried out by the IMS. The sites surveyed represent a variety of physical and geological environments on most continents. The lowest high frequency (>1.4 Hz) noise levels at five sites with igneous or metamorphic geologies were as much as 6 dB below the USGS New Low Noise Model (NLNM) developed by Peterson (1993). These sites were in Oman (local geology consisting of Ordovician metasediments), Egypt (Precambrian granite), Niger (early Proterozoic tonalite and granodiorite), Saudi Arabia (Precambian metasediments), and

  1. Noise and Hearing Loss Prevention

    Science.gov (United States)

    ... visit this page: About CDC.gov . NOISE AND HEARING LOSS PREVENTION Recommend on Facebook Tweet Share Compartir Hearing ... noise levels cannot be adequately reduced. Noise and Hearing Loss on the NIOSH Science Blog Read and comment ...

  2. High Efficiency Computation of the Variances of Structural Evolutionary Random Responses

    Directory of Open Access Journals (Sweden)

    J.H. Lin

    2000-01-01

    Full Text Available For structures subjected to stationary or evolutionary white/colored random noise, their various response variances satisfy algebraic or differential Lyapunov equations. The solution of these Lyapunov equations used to be very difficult. A precise integration method is proposed in the present paper, which solves such Lyapunov equations accurately and very efficiently.

  3. Substation noise screening tool

    Energy Technology Data Exchange (ETDEWEB)

    Maybee, Nigel; Everton, Pascal [HFP Acoustical Consultants Corp. (Canada)], email: nigel.maybee@hfpacoustical.com; Chow, Vincent [Altalink Management Ltd. (Canada)], email: Vincent.Chow@AltaLink.ca

    2011-07-01

    Alberta noise regulations require energy-related facilities to conduct predictions on sound levels, especially for large and medium noise sources. This is usually done with well-known modelling software, but that can be disadvantageous when assessing the noise impact of smaller noise sources, such as transformer substations. This paper focuses on the development of a spreadsheet substation noise screening tool to assess the noise impact of a small transformer substation with precision and ease-of-use. Three aspects must be considered: transformer sound levels, which can be provided by the manufacturer or extracted from accepted sound level references; sound power calculations, which depend on the substation size and operating regime; and sound propagation calculations, which take into account the distance of the receptor from the substation and sound absorption by the air and ground. Comparison of results obtained with this tool with results generated by standard sound modelling software shows the utility, accuracy and ease-of-use of this screening method for assessing the noise impact of transformer substations.

  4. The Feasibility of Noise Control in a Soft Drink Plant

    Directory of Open Access Journals (Sweden)

    Fouladi Dehaghi

    2016-03-01

    Full Text Available Background “Noise” can be defined as any unwanted sound. Soft drink plants, which produce the raw materials used in most carbonated beverage factories, are sources of noise. Objectives This study investigated the noise pollution present in a soft drink CO2 gas injection plant, in order to present noise control measures. Materials and Methods The instructions specified by the canadian center for occupational health and safety (CCOHS were followed during the noise study, and a sound level meter, CEL.450 calibrated with CEL-110.2 based on ISO-9612 methods, was used to record the sound pressure level (SPL at each grid point. SPL was determined in weighting scales A and C. and a noise survey map of equivalent SPLs was drawn for each part. Each part of the floor area of the soft drink factory where SPL exceeded 85 dBA was identified from the noise survey map to determine the causes of high levels of noise. In order to reduce noise level in each part, the absorption coefficient, transmission loss, and noise reduction rate were calculated in the proposed control area. Results According to the study results, noise levels in a CO2 plant’s house and control room ranged from 88 to 102 dB and 79 to 82 dB (A, respectively. In order to reduce the amount of emitted noise in the CO2 plant house and control room, a noise control plan was implemented in each part of the facility; it was met with effective results. Conclusions The findings of this investigation have clearly revealed that plant workers are at risk of developing noise-induced hearing loss. However, after the implementation of a noise control plan in each part of the facility, the noise dose received by workers has significantly decreased. The need to implement a noise conservation program was established.

  5. Discrete least squares polynomial approximation with random evaluations - application to PDEs with Random parameters

    KAUST Repository

    Nobile, Fabio

    2015-01-07

    We consider a general problem F(u, y) = 0 where u is the unknown solution, possibly Hilbert space valued, and y a set of uncertain parameters. We specifically address the situation in which the parameterto-solution map u(y) is smooth, however y could be very high (or even infinite) dimensional. In particular, we are interested in cases in which F is a differential operator, u a Hilbert space valued function and y a distributed, space and/or time varying, random field. We aim at reconstructing the parameter-to-solution map u(y) from random noise-free or noisy observations in random points by discrete least squares on polynomial spaces. The noise-free case is relevant whenever the technique is used to construct metamodels, based on polynomial expansions, for the output of computer experiments. In the case of PDEs with random parameters, the metamodel is then used to approximate statistics of the output quantity. We discuss the stability of discrete least squares on random points show convergence estimates both in expectation and probability. We also present possible strategies to select, either a-priori or by adaptive algorithms, sequences of approximating polynomial spaces that allow to reduce, and in some cases break, the curse of dimensionality

  6. Pneumatic muffler noise.

    Science.gov (United States)

    Cudworth, A L; Hanson, W J; Vuisting, W

    1978-11-01

    Sixty-five commercial pneumatic mufflers in the size range of 1/8 to 3/8-inch American Standard Taper Pipe Thread (NPT) were evaluated for noise level as a function of air supply pressure and back pressure. Also, typical directivity pattern and spectral content were determined. A rating system has been devised, as well as individual prediction formulas, to rank order the mufflers and provide a capability of calculating expected noise levels for a given supply pressure. As this study reveals, noise reductions in excess of 40 dBA may be achieved by employing an efficient pneumatic muffler.

  7. Controlled Noise Seismology

    KAUST Repository

    Hanafy, Sherif M.

    2015-08-19

    We use controlled noise seismology (CNS) to generate surface waves, where we continuously record seismic data while generating artificial noise along the profile line. To generate the CNS data we drove a vehicle around the geophone line and continuously recorded the generated noise. The recorded data set is then correlated over different time windows and the correlograms are stacked together to generate the surface waves. The virtual shot gathers reveal surface waves with moveout velocities that closely approximate those from active source shot gathers.

  8. Noise Suppression Phenomenon in Fiber Raman Amplifier

    Directory of Open Access Journals (Sweden)

    Felinskyi Georgii

    2015-06-01

    Full Text Available The problem of small bit error rate is actual in fiber Raman amplifiers. Our experimental data on the amplified spontaneous emission (ASE with backward pumping as a base of optical noise evaluation are presented in this paper. Raman gain spectrum for useful Stokes low-powered signal is calculated and compared with obtained spectrum of non-coherent ASE noise. It is shown that output optical signal has better gain than the amplified spontaneous emission that leads to appreciable growth of output optical signal-to-noise ratio.

  9. What Do Contrast Threshold Equivalent Noise Studies Actually Measure? Noise vs. Nonlinearity in Different Masking Paradigms.

    Directory of Open Access Journals (Sweden)

    Alex S Baldwin

    Full Text Available The internal noise present in a linear system can be quantified by the equivalent noise method. By measuring the effect that applying external noise to the system's input has on its output one can estimate the variance of this internal noise. By applying this simple "linear amplifier" model to the human visual system, one can entirely explain an observer's detection performance by a combination of the internal noise variance and their efficiency relative to an ideal observer. Studies using this method rely on two crucial factors: firstly that the external noise in their stimuli behaves like the visual system's internal noise in the dimension of interest, and secondly that the assumptions underlying their model are correct (e.g. linearity. Here we explore the effects of these two factors while applying the equivalent noise method to investigate the contrast sensitivity function (CSF. We compare the results at 0.5 and 6 c/deg from the equivalent noise method against those we would expect based on pedestal masking data collected from the same observers. We find that the loss of sensitivity with increasing spatial frequency results from changes in the saturation constant of the gain control nonlinearity, and that this only masquerades as a change in internal noise under the equivalent noise method. Part of the effect we find can be attributed to the optical transfer function of the eye. The remainder can be explained by either changes in effective input gain, divisive suppression, or a combination of the two. Given these effects the efficiency of our observers approaches the ideal level. We show the importance of considering these factors in equivalent noise studies.

  10. Polish version of standardized noise reaction questions for community noise surveys.

    Science.gov (United States)

    Preis, Anna; Kaczmarek, Tomasz; Wojciechowska, Hanna; Zera, Jan; Fields, James M

    2003-01-01

    This article presents the Polish version of two standardized noise reaction questions for community noise surveys. An internationally comparable noise reaction measure for social surveys was published by Fields et al. as a result of work performed by the Community Response to Noise Team of the International Commission on the Biological Effects of Noise. This measure consists of two recommended noise reaction questions: a 5-point verbal scale question and a 0-10-point numeric scale question. The Polish words for a 5-point noise annoyance verbal scale were selected by respondents from a group of 21 potential adverbs following the method described by Fields et al. The same standardized empirical study protocol was used to select annoyance scale words (a 5-point verbal scale question) for the nine different languages. The following words for a 5-point noise annoyance scale were obtained: not at all, a little, rather, substantially, extremely annoying. The Polish version of the scale described in this paper has international counterparts. It means that our data expand the world database on human reactions to noise in different communities and become more comparable with the data from other countries.

  11. Cochlear implant optimized noise reduction

    Science.gov (United States)

    Mauger, Stefan J.; Arora, Komal; Dawson, Pam W.

    2012-12-01

    Noise-reduction methods have provided significant improvements in speech perception for cochlear implant recipients, where only quality improvements have been found in hearing aid recipients. Recent psychoacoustic studies have suggested changes to noise-reduction techniques specifically for cochlear implants, due to differences between hearing aid recipient and cochlear implant recipient hearing. An optimized noise-reduction method was developed with significantly increased temporal smoothing of the signal-to-noise ratio estimate and a more aggressive gain function compared to current noise-reduction methods. This optimized noise-reduction algorithm was tested with 12 cochlear implant recipients over four test sessions. Speech perception was assessed through speech in noise tests with three noise types; speech-weighted noise, 20-talker babble and 4-talker babble. A significant speech perception improvement using optimized noise reduction over standard processing was found in babble noise and speech-weighted noise and over a current noise-reduction method in speech-weighted noise. Speech perception in quiet was not degraded. Listening quality testing for noise annoyance and overall preference found significant improvements over the standard processing and over a current noise-reduction method in speech-weighted and babble noise types. This optimized method has shown significant speech perception and quality improvements compared to the standard processing and a current noise-reduction method.

  12. Random processes in nuclear reactors

    CERN Document Server

    Williams, M M R

    1974-01-01

    Random Processes in Nuclear Reactors describes the problems that a nuclear engineer may meet which involve random fluctuations and sets out in detail how they may be interpreted in terms of various models of the reactor system. Chapters set out to discuss topics on the origins of random processes and sources; the general technique to zero-power problems and bring out the basic effect of fission, and fluctuations in the lifetime of neutrons, on the measured response; the interpretation of power reactor noise; and associated problems connected with mechanical, hydraulic and thermal noise sources

  13. Comparison of phase noise simulation techniques on a BJT LC oscillator.

    Science.gov (United States)

    Forbes, Leonard; Zhang, Chengwei; Zhang, Binglei; Chandra, Yudi

    2003-06-01

    The phase noise resulting from white and flicker noise in a bipolar junction transistor (BJT) LC oscillator is investigated. Large signal transient time domain SPICE simulations of phase noise resulting from the random-phase flicker and white noise in a 2 GHz BJT LC oscillator have been performed and demonstrated. The simulation results of this new technique are compared with Eldo RF and Spectre RF based on linear circuit concepts and experimental result reported in the literature.

  14. Fluidic Injection for Jet Noise Reduction

    Science.gov (United States)

    Henderson, Brenda

    2010-01-01

    Investigations into fluidic injection for jet noise reduction began over 50 years ago. Studies have included water and air injection for the reduction of noise in scale model jets and jet engines and water injection for the reduction of excess overpressures on the Space Shuttle at lift-off. Injection systems have included high pressure microjets as well as larger scale injectors operating at pressures that can be achieved in real jet engines. An historical perspective highlighting noise reduction potential is presented for injection concepts investigated over the last 50 years. Results from recent investigations conducted at NASA are presented for supersonic and subsonic dual-stream jets. The noise reduction benefits achieved through fluidic contouring using an azimuthally controlled nozzle will be discussed.

  15. Genetic noise control via protein oligomerization

    Energy Technology Data Exchange (ETDEWEB)

    Ghim, C; Almaas, E

    2008-06-12

    Gene expression in a cell entails random reaction events occurring over disparate time scales. Thus, molecular noise that often results in phenotypic and population-dynamic consequences sets a fundamental limit to biochemical signaling. While there have been numerous studies correlating the architecture of cellular reaction networks with noise tolerance, only a limited effort has been made to understand the dynamical role of protein-protein associations. We have developed a fully stochastic model for the positive feedback control of a single gene, as well as a pair of genes (toggle switch), integrating quantitative results from previous in vivo and in vitro studies. In particular, we explicitly account for the fast protein binding-unbinding kinetics, RNA polymerases, and the promoter/operator sequences of DNA. We find that the overall noise-level is reduced and the frequency content of the noise is dramatically shifted to the physiologically irrelevant high-frequency regime in the presence of protein dimerization. This is independent of the choice of monomer or dimer as transcription factor and persists throughout the multiple model topologies considered. For the toggle switch, we additionally find that the presence of a protein dimer, either homodimer or heterodimer, may significantly reduce its intrinsic switching rate. Hence, the dimer promotes the robust function of bistable switches by preventing the uninduced (induced) state from randomly being induced (uninduced). The specific binding between regulatory proteins provides a buffer that may prevent the propagation of fluctuations in genetic activity. The capacity of the buffer is a non-monotonic function of association-dissociation rates. Since the protein oligomerization per se does not require extra protein components to be expressed, it provides a basis for the rapid control of intrinsic or extrinsic noise. The stabilization of phenotypically important toggle switches, and nested positive feedback loops in

  16. Acoustics Noise Test Cell

    Data.gov (United States)

    Federal Laboratory Consortium — The Acoustic Noise Test Cell at the NASA/Caltech Jet Propulsion Laboratory (JPL) is located adjacent to the large vibration system; both are located in a class 10K...

  17. Acoustic ambient noise recorder

    Digital Repository Service at National Institute of Oceanography (India)

    Saran, A.K.; Navelkar, G.S.; Almeida, A.M.; More, S.R.; Chodankar, P.V.; Murty, C.S.

    with a robust outfit that can withstand high pressures and chemically corrosion resistant materials. Keeping these considerations in view, a CMOS micro-controller-based marine acoustic ambient noise recorder has been developed with a real time clock...

  18. Oscillator Phase Noise: A Geometrical Approach

    DEFF Research Database (Denmark)

    Djurhuus, Torsten; Krozer, Viktor; Vidkjær, Jens

    2009-01-01

    We construct a coordinate-independent description of oscillator linear response through a decomposition scheme derived independently of any Floquet theoretic results. Trading matrix algebra for a simpler graphical methodology, the text will present the reader with an opportunity to gain an intuit...... an intuitive understanding of the well-known phase noise macromodel. The topics discussed in this paper include the following: orthogonal decompositions, AM–PM conversion, and nonhyperbolic oscillator noise response....

  19. Blue Whales Respond to Anthropogenic Noise

    OpenAIRE

    Melcón, Mariana L.; Amanda J Cummins; Kerosky, Sara M.; Roche, Lauren K.; Wiggins, Sean M.; Hildebrand, John A.

    2012-01-01

    Anthropogenic noise may significantly impact exposed marine mammals. This work studied the vocalization response of endangered blue whales to anthropogenic noise sources in the mid-frequency range using passive acoustic monitoring in the Southern California Bight. Blue whales were less likely to produce calls when mid-frequency active sonar was present. This reduction was more pronounced when the sonar source was closer to the animal, at higher sound levels. The animals were equally likely to...

  20. Core/Combustor Noise - Research Overview

    Science.gov (United States)

    Hultgren, Lennart S.

    2017-01-01

    Contributions from the combustor to the overall propulsion noise of civilian transport aircraft are starting to become important due to turbofan design trends and advances in mitigation of other noise sources. Future propulsion systems for ultra-efficient commercial air vehicles are projected to be of increasingly higher bypass ratio from larger fans combined with much smaller cores, with ultra-clean burning fuel-flexible combustors. Unless effective noise-reduction strategies are developed, combustor noise is likely to become a prominent contributor to overall airport community noise in the future. This presentation gives a brief overview of the NASA outlook on pertinent issues and far-term research needs as well as current and planned research in the core/combustor-noise area. The research described herein is aligned with the NASA Ultra-Efficient Commercial Transport strategic thrust and is supported by the NASA Advanced Air Vehicle Program, Advanced Air Transport Technology Project, under the Aircraft Noise Reduction Subproject. The overarching goal of the Advanced Air Transport Technology (AATT) Project is to explore and develop technologies and concepts to revolutionize the energy efficiency and environmental compatibility of fixed wing transport aircrafts. These technological solutions are critical in reducing the impact of aviation on the environment even as this industry and the corresponding global transportation system continue to grow.

  1. Supersonics Project - Airport Noise Tech Challenge

    Science.gov (United States)

    Bridges, James

    2010-01-01

    The Airport Noise Tech Challenge research effort under the Supersonics Project is reviewed. While the goal of "Improved supersonic jet noise models validated on innovative nozzle concepts" remains the same, the success of the research effort has caused the thrust of the research to be modified going forward in time. The main activities from FY06-10 focused on development and validation of jet noise prediction codes. This required innovative diagnostic techniques to be developed and deployed, extensive jet noise and flow databases to be created, and computational tools to be developed and validated. Furthermore, in FY09-10 systems studies commissioned by the Supersonics Project showed that viable supersonic aircraft were within reach using variable cycle engine architectures if exhaust nozzle technology could provide 3-5dB of suppression. The Project then began to focus on integrating the technologies being developed in its Tech Challenge areas to bring about successful system designs. Consequently, the Airport Noise Tech Challenge area has shifted efforts from developing jet noise prediction codes to using them to develop low-noise nozzle concepts for integration into supersonic aircraft. The new plan of research is briefly presented by technology and timelines.

  2. A model for phase noise generation in amplifiers.

    Science.gov (United States)

    Tomlin, T D; Fynn, K; Cantoni, A

    2001-11-01

    In this paper, a model is presented for predicting the phase modulation (PM) and amplitude modulation (AM) noise in bipolar junction transistor (BJT) amplifiers. The model correctly predicts the dependence of phase noise on the signal frequency (at a particular carrier offset frequency), explains the noise shaping of the phase noise about the signal frequency, and shows the functional dependence on the transistor parameters and the circuit parameters. Experimental studies on common emitter (CE) amplifiers have been used to validate the PM noise model at carrier frequencies between 10 and 100 MHz.

  3. Pitch Estimation, Voicing Decision, and Noise Spectrum Estimation for Speech Corrupted by High Levels of Additive Noise.

    Science.gov (United States)

    Krubsack, David Allan

    1990-01-01

    This dissertation presents two algorithms that extract parameters which are important to speech processing in high levels of noise. The first algorithm determines whether a signal containing noise corrupted human speech is voiced or not and estimates the fundamental frequency (pitch) of voiced speech. The second algorithm produces an estimate of the additive noise which is corrupting the speech. Previous research related to the voicing decision and pitch estimation has been concentrated at signal-to -noise ratios (SNRs) above 0 dB. Consequently, speech processing requiring the extraction of these parameters in higher levels of noise could not be performed with much success. The research presented in this dissertation concentrates on SNRs around and below 0 dB. Although the algorithm, based on the autocorrelation function, is designed to work well for high levels of noise, good results for the no noise case have been maintained. The idea of a confidence measure for parameter estimation is introduced. Confidence measures are defined and developed for both the voicing decision and the pitch estimation algorithms. Estimation of noise that is corrupting a speech signal has been motivated by the need to enhance the corrupted speech. Previous research has concentrated on speech which is band limited to about 3500 Hz. Therefore, the estimation of the noise corrupting high frequency speech had not been considered. The noise estimation algorithm presented in this dissertation considers the effects of high frequency speech on the noise estimate in addition to the effects of low frequency speech. A new spectral averaging method is introduced which significantly reduces the corrupting effect of the speech components on the noise estimate for SNRs above 0 dB. The algorithm is tested for stationary white noise, stationary non-white noise, and non-stationary white noise.

  4. Ambient Noise in an Urbanized Tidal Channel

    Science.gov (United States)

    Bassett, Christopher

    In coastal environments, when topographic and bathymetric constrictions are combined with large tidal amplitudes, strong currents (> 2 m/s) can occur. Because such environments are relatively rare and difficult to study, until recently, they have received little attention from the scientific community. However, in recent years, interest in developing tidal hydrokinetic power projects in these environments has motivated studies to improve this understanding. In order to support an analysis of the acoustic effects of tidal power generation, a multi-year study was conducted at a proposed project site in Puget Sound (WA) are analyzed at a site where peak currents exceeded 3.5 m/s. From these analyses, three noise sources are shown to dominate the observed variability in ambient noise between 0.02-30 kHz: anthropogenic noise from vessel traffic, sediment-generated noise during periods of strong currents, and flow-noise resulting from turbulence advected over the hydrophones. To assess the contribution of vessel traffic noise, one calendar year of Automatic Identification System (AIS) ship-traffic data was paired with hydrophone recordings. The study region included inland waters of the Salish Sea within a 20 km radius of the hydrophone deployment site in northern Admiralty Inlet. The variability in spectra and hourly, daily, and monthly ambient noise statistics for unweighted broadband and M-weighted sound pressure levels is driven largely by vessel traffic. Within the one-year study period, at least one AIS transmitting vessel is present in the study area 90% of the time and over 1,363 unique vessels are recorded. A noise budget for vessels equipped with AIS transponders identifies cargo ships, tugs, and passenger vessels as the largest contributors to noise levels. A simple model to predict received levels at the site based on an incoherent summation of noise from different vessel types yields a cumulative probability density function of broadband sound pressure

  5. Noise performance of frequency modulation Kelvin force microscopy

    Directory of Open Access Journals (Sweden)

    Heinrich Diesinger

    2014-01-01

    Full Text Available Noise performance of a phase-locked loop (PLL based frequency modulation Kelvin force microscope (FM-KFM is assessed. Noise propagation is modeled step by step throughout the setup using both exact closed loop noise gains and an approximation known as “noise gain” from operational amplifier (OpAmp design that offers the advantage of decoupling the noise performance study from considerations of stability and ideal loop response. The bandwidth can be chosen depending on how much noise is acceptable and it is shown that stability is not an issue up to a limit that will be discussed. With thermal and detector noise as the only sources, both approaches yield PLL frequency noise expressions equal to the theoretical value for self-oscillating circuits and in agreement with measurement, demonstrating that the PLL components neither modify nor contribute noise. Kelvin output noise is then investigated by modeling the surrounding bias feedback loop. A design rule is proposed that allows choosing the AC modulation frequency for optimized sharing of the PLL bandwidth between Kelvin and topography loops. A crossover criterion determines as a function of bandwidth, temperature and probe parameters whether thermal or detector noise is the dominating noise source. Probe merit factors for both cases are then established, suggesting how to tackle noise performance by probe design. Typical merit factors of common probe types are compared. This comprehensive study is an encouraging step toward a more integral performance assessment and a remedy against focusing on single aspects and optimizing around randomly chosen key values.

  6. Low-frequency-noise complaints

    DEFF Research Database (Denmark)

    Pedersen, Christian Sejer; Møller, Henrik; Persson-Waye, Kerstin

    2008-01-01

    From 203 cases of low-frequency complaints a random selection of twenty-one cases were investigated. The main aim of the investigation was to answer the question whether the annoyance is caused by an external physical sound or by a physically non-existing sound, i.e. low-frequency tinnitus. Noise...... of the complainants are annoyed by a physical sound (20-180 Hz), while others suffer from low-frequency tinnitus (perceived frequency 40-100 Hz). Physical sound at frequencies below 20 Hz (infrasound) is not responsible for the annoyance - or at all audible - in any of the investigated cases, and none...... of the complainants has extraordinary hearing sensitivity at low frequencies. For comparable cases of low-frequency noise complaints in general, it is anticipated that physical sound is responsible in a substantial part of the cases, while low-frequency tinnitus is responsible in another substantial part of the cases....

  7. The Role of Visual Noise in Influencing Mental Load and Fatigue in a Steady-State Motion Visual Evoked Potential-Based Brain-Computer Interface.

    Science.gov (United States)

    Xie, Jun; Xu, Guanghua; Luo, Ailing; Li, Min; Zhang, Sicong; Han, Chengcheng; Yan, Wenqiang

    2017-08-14

    As a spatial selective attention-based brain-computer interface (BCI) paradigm, steady-state visual evoked potential (SSVEP) BCI has the advantages of high information transfer rate, high tolerance to artifacts, and robust performance across users. However, its benefits come at the cost of mental load and fatigue occurring in the concentration on the visual stimuli. Noise, as a ubiquitous random perturbation with the power of randomness, may be exploited by the human visual system to enhance higher-level brain functions. In this study, a novel steady-state motion visual evoked potential (SSMVEP, i.e., one kind of SSVEP)-based BCI paradigm with spatiotemporal visual noise was used to investigate the influence of noise on the compensation of mental load and fatigue deterioration during prolonged attention tasks. Changes in α, θ, θ + α powers, θ/α ratio, and electroencephalography (EEG) properties of amplitude, signal-to-noise ratio (SNR), and online accuracy, were used to evaluate mental load and fatigue. We showed that presenting a moderate visual noise to participants could reliably alleviate the mental load and fatigue during online operation of visual BCI that places demands on the attentional processes. This demonstrated that noise could provide a superior solution to the implementation of visual attention controlling-based BCI applications.

  8. Ultra low-noise charge coupled device

    Science.gov (United States)

    Janesick, James R. (Inventor)

    1993-01-01

    Special purpose CCD designed for ultra low-noise imaging and spectroscopy applications that require subelectron read noise floors, wherein a non-destructive output circuit operating near its 1/f noise regime is clocked in a special manner to read a single pixel multiple times. Off-chip electronics average the multiple values, reducing the random noise by the square-root of the number of samples taken. Noise floors below 0.5 electrons rms are possible in this manner. In a preferred embodiment of the invention, a three-phase CCD horizontal register is used to bring a pixel charge packet to an input gate adjacent a floating gate amplifier. The charge is then repeatedly clocked back and forth between the input gate and the floating gate. Each time the charge is injected into the potential well of the floating gate, it is sensed non-destructively. The floating gate amplifier is provided with a reference voltage of a fixed value and a pre-charge gate for resetting the amplifier between charge samples to a constant gain. After the charge is repeatedly sampled a selected number of times, it is transferred by means of output gates, back into the horizontal register, where it is clocked in a conventional manner to a diffusion MOSFET amplifier. It can then be either sampled (destructively) one more time or otherwise discarded.

  9. Noise monitoring and adverse health effects in residents in different functional areas of Luzhou, China.

    Science.gov (United States)

    Han, Zhi-Xia; Lei, Zhang-Heng; Zhang, Chun-Lian; Xiong, Wei; Gan, Zhong-Lin; Hu, Ping; Zhang, Qing-Bi

    2015-03-01

    The purpose of the study was to investigate the noise pollution situation and the resulting adverse effect on residents' health in Luzhou, China, to provide data for noise pollution prevention policies and interventions. Four different functional areas (commercial, construction, residential, and transportation hub areas) were chosen to monitor noise level for 3 months. The survey was performed by questionnaire on the spot on randomly selected individuals; it collected data on the impact of noise on residents' health (quality of sleep, high blood pressure, subjective feeling of nervous system damage, and attention) as well as the knowledge of noise-induced health damage, the degree of adaptation to noise, and their solutions. The noise levels of residential, commercial, transportation, and construction areas exceeded the national standards (P health hazards associated with noise; 64.57% of residents have adapted to the current noise environment. Most of them have to close the doors and windows to reduce noise. The noise pollution situation in Luzhou, China, is serious, especially the traffic noise pollution. Residents pay less attention to it and adopt single measures to reduce the noise. We should work toward the prevention and control of traffic noise and improve the residents' awareness to reduce the adverse health effects of noise. © 2014 APJPH.

  10. Noise sensitivity and sleep disturbance

    NARCIS (Netherlands)

    Laszlo, H.E.; Janssen, S.A.; Babisch, W.; Hansell, A.L.

    2012-01-01

    It has been shown that noise induced health effects are strongly related to non-acoustical factors such as noise sensitivity. It is a stable personality trait and it can be conceptualised as a causal pathway confounder and/or effect modifier between noise and health. Furthermore noise sensitivity

  11. The influence of amplifier, interface and biological noise on signal quality in high-resolution EEG recordings.

    Science.gov (United States)

    Scheer, Hans J; Sander, Tilmann; Trahms, Lutz

    2006-02-01

    First, the intrinsic random noise sources of a biopotential measurement in general are reviewed. For the special case of an electroencephalographic (EEG) measurement we have extended the commonly used amplifier noise model by biological generated background noise. As the strongest of all noise sources involved will dominate the resulting signal to noise ratio (S/N), we have investigated under which conditions this will be the case. We illustrate experimentally that up to 100 Hz S/N practically depends only on cortical generated background noise, while at a few hundred Hz or more amplifier and thermal noise of interelectrode resistance are the major sources.

  12. Socio-psychological airplane noise investigation in the districts of three Swiss airports: Zurich, Geneva and Basel

    Science.gov (United States)

    Graf, R.; Mueller, R.; Meier, H. P.

    1980-01-01

    The results of noise measurements and calculations are available in the form of noise maps for each of the three areas. To measure the stress due to airplane noise the Noise and Number Index (NNI) was applied. In the vicinities of the airports, 400 households were randomly selected in each of the three noise zones (of 10 NNI intervals each). A total of 3939 questionnaires could be evaluated, one quarter of which came from areas without airplane noise. Concurrently, traffic noise was measured in areas of Basel and expressed in sum total levels L sub 50 and the reaction of 944 persons was elicited by interrogation.

  13. Noise-invariant Neurons in the Avian Auditory Cortex: Hearing the Song in Noise

    Science.gov (United States)

    Moore, R. Channing; Lee, Tyler; Theunissen, Frédéric E.

    2013-01-01

    Given the extraordinary ability of humans and animals to recognize communication signals over a background of noise, describing noise invariant neural responses is critical not only to pinpoint the brain regions that are mediating our robust perceptions but also to understand the neural computations that are performing these tasks and the underlying circuitry. Although invariant neural responses, such as rotation-invariant face cells, are well described in the visual system, high-level auditory neurons that can represent the same behaviorally relevant signal in a range of listening conditions have yet to be discovered. Here we found neurons in a secondary area of the avian auditory cortex that exhibit noise-invariant responses in the sense that they responded with similar spike patterns to song stimuli presented in silence and over a background of naturalistic noise. By characterizing the neurons' tuning in terms of their responses to modulations in the temporal and spectral envelope of the sound, we then show that noise invariance is partly achieved by selectively responding to long sounds with sharp spectral structure. Finally, to demonstrate that such computations could explain noise invariance, we designed a biologically inspired noise-filtering algorithm that can be used to separate song or speech from noise. This novel noise-filtering method performs as well as other state-of-the-art de-noising algorithms and could be used in clinical or consumer oriented applications. Our biologically inspired model also shows how high-level noise-invariant responses could be created from neural responses typically found in primary auditory cortex. PMID:23505354

  14. Aircraft noise calculation and synthesis in a non-standard atmosphere

    NARCIS (Netherlands)

    Arntzen, M.

    2014-01-01

    The atmosphere modifies the emitted sound waves of an aircraft during propagation and is therefore important in the calculation of noise contours or synthesis. Noise contours present the resulting noise levels on the ground and are, as such, often applied for regulatory purposes. Aircraft noise

  15. The Transimpedance Amplifier Noise Optimization for the Atmospheric Optical Link Receiver

    Directory of Open Access Journals (Sweden)

    A. Prokes

    1996-12-01

    Full Text Available This paper deals with design of wideband low-noise preamplifier of atmospheric optical link receiver. Sources of noise and the noise models for the PIN photodiode coupled to a transimpedance amplifier are described here. This paper presents the way of optimization the signal to noise ratio at the required frequency range.

  16. Selected papers on noise and stochastic processes

    CERN Document Server

    1954-01-01

    Six classic papers on stochastic process, selected to meet the needs of physicists, applied mathematicians, and engineers. Contents: 1.Chandrasekhar, S.: Stochastic Problems in Physics and Astronomy. 2. Uhlenbeck, G. E. and Ornstein, L. S.: On the Theory of the Browninan Motion. 3. Ming Chen Wang and Uhlenbeck, G. E.: On the Theory of the Browninan Motion II. 4. Rice, S. O.: Mathematical Analysis of Random Noise. 5. Kac, Mark: Random Walk and the Theory of Brownian Motion. 6. Doob, J. L.: The Brownian Movement and Stochastic Equations. Unabridged republication of the Dover reprint (1954). Pre

  17. Noise and Dissipation on Coadjoint Orbits

    Science.gov (United States)

    Arnaudon, Alexis; De Castro, Alex L.; Holm, Darryl D.

    2018-02-01

    We derive and study stochastic dissipative dynamics on coadjoint orbits by incorporating noise and dissipation into mechanical systems arising from the theory of reduction by symmetry, including a semidirect product extension. Random attractors are found for this general class of systems when the Lie algebra is semi-simple, provided the top Lyapunov exponent is positive. We study in details two canonical examples, the free rigid body and the heavy top, whose stochastic integrable reductions are found and numerical simulations of their random attractors are shown.

  18. Noise reduction based on partial-reference, dual-tree complex wavelet transform shrinkage.

    Science.gov (United States)

    Fierro, Massimo; Ha, Ho-Gun; Ha, Yeong-Ho

    2013-05-01

    This paper presents a novel way to reduce noise introduced or exacerbated by image enhancement methods, in particular algorithms based on the random spray sampling technique, but not only. According to the nature of sprays, output images of spray-based methods tend to exhibit noise with unknown statistical distribution. To avoid inappropriate assumptions on the statistical characteristics of noise, a different one is made. In fact, the non-enhanced image is considered to be either free of noise or affected by non-perceivable levels of noise. Taking advantage of the higher sensitivity of the human visual system to changes in brightness, the analysis can be limited to the luma channel of both the non-enhanced and enhanced image. Also, given the importance of directional content in human vision, the analysis is performed through the dual-tree complex wavelet transform (DTWCT). Unlike the discrete wavelet transform, the DTWCT allows for distinction of data directionality in the transform space. For each level of the transform, the standard deviation of the non-enhanced image coefficients is computed across the six orientations of the DTWCT, then it is normalized. The result is a map of the directional structures present in the non-enhanced image. Said map is then used to shrink the coefficients of the enhanced image. The shrunk coefficients and the coefficients from the non-enhanced image are then mixed according to data directionality. Finally, a noise-reduced version of the enhanced image is computed via the inverse transforms. A thorough numerical analysis of the results has been performed in order to confirm the validity of the proposed approach.

  19. A Multi-Stage Method for Connecting Participatory Sensing and Noise Simulations

    Directory of Open Access Journals (Sweden)

    Mingyuan Hu

    2015-01-01

    Full Text Available Most simulation-based noise maps are important for official noise assessment but lack local noise characteristics. The main reasons for this lack of information are that official noise simulations only provide information about expected noise levels, which is limited by the use of large-scale monitoring of noise sources, and are updated infrequently. With the emergence of smart cities and ubiquitous sensing, the possible improvements enabled by sensing technologies provide the possibility to resolve this problem. This study proposed an integrated methodology to propel participatory sensing from its current random and distributed sampling origins to professional noise simulation. The aims of this study were to effectively organize the participatory noise data, to dynamically refine the granularity of the noise features on road segments (e.g., different portions of a road segment, and then to provide a reasonable spatio-temporal data foundation to support noise simulations, which can be of help to researchers in understanding how participatory sensing can play a role in smart cities. This study first discusses the potential limitations of the current participatory sensing and simulation-based official noise maps. Next, we explain how participatory noise data can contribute to a simulation-based noise map by providing (1 spatial matching of the participatory noise data to the virtual partitions at a more microscopic level of road networks; (2 multi-temporal scale noise estimations at the spatial level of virtual partitions; and (3 dynamic aggregation of virtual partitions by comparing the noise values at the relevant temporal scale to form a dynamic segmentation of each road segment to support multiple spatio-temporal noise simulations. In this case study, we demonstrate how this method could play a significant role in a simulation-based noise map. Together, these results demonstrate the potential benefits of participatory noise data as dynamic

  20. Occupational Noise-induced Hearing Loss

    Directory of Open Access Journals (Sweden)

    MH Azizi

    2010-06-01

    Full Text Available Noise-induced hearing loss (NIHL is a well-known entity in daily practice of otolaryngology. A wide variety of NIHLs are work-related. Occupational noise is the most common cause of NIHL in adults which is up to now considered incurable and the best approach to it is to utilize maximal protection. An effective noise exposure prevention program consists of identification of sources of noise and implementation of controlling measures and regulations at working environments as well as performing periodic audiologic evaluation of those who are working at noisy environments. The present paper, briefly reviews occupational NIHL mainly based on the related data available on PubMed up to early 2010.

  1. Annoyance caused by propeller airplane flyover noise

    Science.gov (United States)

    Mccurdy, D. A.; Powell, C. A.

    1984-01-01

    Laboratory experiments were conducted to provide information on quantifying the annoyance response of people to propeller airplane noise. The items of interest were current noise metrics, tone corrections, duration corrections, critical band corrections, and the effects of engine type, operation type, maximum takeoff weight, blade passage frequency, and blade tip speed. In each experiment, 64 subjects judged the annoyance of recordings of propeller and jet airplane operations presented at d-weighted sound pressure levels of 70, 80, and 90 dB in a testing room which simulates the outdoor acoustic environment. The first experiment examined 11 propeller airplanes with maximum takeoff weights greater than or equal to 5700 kg. The second experiment examined 14 propeller airplanes weighting 5700 kg or less. Five jet airplanes were included in each experiment. For both the heavy and light propeller airplanes, perceived noise level and perceived level (Stevens Mark VII procedure) predicted annoyance better than other current noise metrics.

  2. A new perspective on behavioral inconsistency and neural noise in aging: Compensatory speeding of neural communication

    Directory of Open Access Journals (Sweden)

    S. Lee Hong

    2012-09-01

    Full Text Available This paper seeks to present a new perspective on the aging brain. Here, we make connections between two key phenomena of brain aging: 1 increased neural noise or random background activity; and 2 slowing of brain activity. Our perspective proposes the possibility that the slowing of neural processing due to decreasing nerve conduction velocities leads to a compensatory speeding of neuron firing rates. These increased firing rates lead to a broader distribution of power in the frequency spectrum of neural oscillations, which we propose, can just as easily be interpreted as neural noise. Compensatory speeding of neural activity, as we present, is constrained by the: A availability of metabolic energy sources; and B competition for frequency bandwidth needed for neural communication. We propose that these constraints lead to the eventual inability to compensate for age-related declines in neural function that are manifested clinically as deficits in cognition, affect, and motor behavior.

  3. Underwater Noise Modelling of Wave Energy Devices

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    Future large-scale implementation of wave energy converts (WECs) will introduce an anthropogenic activity in the ocean which may contribute to underwater noise. The Ocean houses several marine species with acoustic sensibility; consequently the potential impact of the underwater noise needs to be addressed. At present, there are no acoustic impact studies based on acquired data. The WEAM project (Wave Energy Acoustic Monitoring) aims at developing an underwater noise monitoring plan for WECs. The development of an acoustic monitoring plan must consider the sound propagation in the ocean, identify noise sources, understand the operational characteristics and select adequate instrumentation. Any monitoring strategy must involve in-situ measurements. However, the vast distances which sound travels within the ocean, can make in-situ measurements covering the entire area of interest, impracticable. This difficulty can be partially overcome through acoustic numerical modelling. This paper presents a synthetic study, on the application of acoustic forward modelling and the evaluation of the impact of noise produced by wave energy devices on marine mammals using criteria based on audiograms of dolphins, or other species. The idea is to illustrate the application of that methodology, and to show to what extent it allows for estimating distances of impacts due to acoustic noise.

  4. Resistive Switching Assisted by Noise

    OpenAIRE

    Patterson, G. A.; Fierens, P. I.; Grosz, D. F.

    2013-01-01

    We extend results by Stotland and Di Ventra on the phenomenon of resistive switching aided by noise. We further the analysis of the mechanism underlying the beneficial role of noise and study the EPIR (Electrical Pulse Induced Resistance) ratio dependence with noise power. In the case of internal noise we find an optimal range where the EPIR ratio is both maximized and independent of the preceding resistive state. However, when external noise is considered no beneficial effect is observed.

  5. Random noise reduction by smoothing of CRS attributes = : Redução do ruído aleatório mediante a suavização dos atributos CRS

    OpenAIRE

    Dany Rueda Serrano

    2013-01-01

    Resumo: A razão sinal-ruído, geralmente abreviada por razão S/N (do Inglês signal-to-noise ratio) é bastante afetada por ruídos aleatórios, os quais degradam a continuidade e identificação de refletores, com prejuízos para interpretação geológica. Com vistas à superação dessas dificuldades, apresentamos neste trabalho uma técnica baseado na suavização de parâmetros obtidos pela aplicação do método de empilhamento Common-Reection-Surface (CRS). A suavização é realizada através da utilização de...

  6. Effects of night time road traffic noise—an overview of laboratory and field studies on noise dose and subjective noise sensitivity

    Science.gov (United States)

    Öhrström, E.; Rylander, R.; Björkman, M.

    1988-12-01

    This paper presents an overview of research on sleep and noise at the Department of Environmental Hygiene, University of Gothenburg. Different methods were developed to study primary and after effects of night time road traffic noise on sleep. Three one-week laboratory experiments were undertaken to study the relevance of different noise descriptors— Leq, maximum peak noise level and number of events with high peak noise levels—for sleep disturbance effects. The noise exposure was either single noise evenys or a continuous, even road traffic noise. It was concluded that Leq was not related to sleep disturbance effects. Peak noise levels were significantly related to subjective sleep quality and body movements. Results from a third continuing study showed that there is a threshold for effects of the number of single noise events on sleep quality. Habituation to noise among subjects with differing noise sensitivity was studied in a two-week experiment. A significant noise effect on subjective sleep quality was found among sensitive subjects only. No habituation was seen for the negative influence of noise on sleep quality, mood and performance. Long-term effects of road traffic noise were also investigated in a field survey among 106 individuals. This study revealed the presence of a decrease in sleep quality as well as psycho-social effects on tiredness and mood, together with increased reports of headaches and nervous stomach. As in the laboratory study, sensitive individuals were more affected by noise than less sensitive individuals.

  7. Motor noise is rich signal in autism research and pharmacological treatments.

    Science.gov (United States)

    Torres, E B; Denisova, K

    2016-11-21

    The human body is in constant motion, from every breath that we take, to every visibly purposeful action that we perform. Remaining completely still on command is a major achievement as involuntary fluctuations in our motions are difficult to keep under control. Here we examine the noise-to-signal ratio of micro-movements present in time-series of head motions extracted from resting-state functional magnetic resonance imaging scans in 1048 participants. These included individuals with autism spectrum disorders (ASD) and healthy-controls in shared data from the Autism Brain Imaging Data Exchange (ABIDE) and the Attention-Deficit Hyperactivity Disorder (ADHD-200) databases. We find excess noise and randomness in the ASD cases, suggesting an uncertain motor-feedback signal. A power-law emerged describing an orderly relation between the dispersion and shape of the probability distribution functions best describing the stochastic properties under consideration with respect to intelligence quotient (IQ-scores). In ASD, deleterious patterns of noise are consistently exacerbated with the presence of secondary (comorbid) neuropsychiatric diagnoses, lower verbal and performance intelligence, and autism severity. Importantly, such patterns in ASD are present whether or not the participant takes psychotropic medication. These data unambiguously establish specific noise-to-signal levels of head micro-movements as a biologically informed core feature of ASD.

  8. VOLUNTARY NOISE MAPPING FOR SMART CITY

    Directory of Open Access Journals (Sweden)

    V. Poslončec-Petrić

    2016-09-01

    noise in real time. In this paper are presented the voluntary acquisitioned data of noise level measurement in Zagreb through a mobile application named Noise Tube, which were used as the basis for creating the dynamic noise map. The paper describes how citizens through voluntarily collected geoinformation can directly influence decision-making in their community, which certainly affects the quality of life.

  9. Voluntary Noise Mapping for Smart City

    Science.gov (United States)

    Poslončec-Petrić, V.; Vuković, V.; Frangeš, S.; Bačić, Ž.

    2016-09-01

    . In this paper are presented the voluntary acquisitioned data of noise level measurement in Zagreb through a mobile application named Noise Tube, which were used as the basis for creating the dynamic noise map. The paper describes how citizens through voluntarily collected geoinformation can directly influence decision-making in their community, which certainly affects the quality of life.

  10. Extraaural effects of noise

    Energy Technology Data Exchange (ETDEWEB)

    Marth, E.; Gruber, M.; Koeck, M.; Moese, J.R.; Gallasch, E.; Fueger, G.F.

    This study investigates the effects of a short-term exposition (15 sec) to an indifferent, broad spectrum of noise. Noise levels were set at 85 dB(A) and 110 dB(A). Stress mediators and compensatory mechanisms were studied in 30 test persons. The study was particularly concerned with the metabolic processes providing energy for fight or flight reactions. Most importantly triglycerides are hydrolysed in order to be able to produce the fatty acids that are released. This catabolism is a function of an ACTH-activated lipase. In 93% of the person tested, triglycerides decreased by 7 to 40% of the initial concentration. Blood sugar reaction can be described in two phases: Initially, there was a slight increase in the blood sugar concentration; at higher noise levels, it was followed by a slight decrease. This behaviour was even more characteristic of the insulin concentration. At 85 dB(A), no significant difference concentration was found compared with the levels previous to noise exposition. At 110 dB(A), there was a significant decrease in the insulin level. Vaso constriction of the peripheral blood vessels is a useful parameter for the stress caused by noise. This was shown by registering the finger pulse during the test.

  11. Noise and Function

    CERN Document Server

    Weinstein, Steven

    2016-01-01

    Noise is widely understood to be something that interferes with a signal or process. Thus, it is generally thought to be destructive, obscuring signals and interfering with function. However, early in the 20th century, mechanical engineers found that mechanisms inducing additional vibration in mechanical systems could prevent sticking and hysteresis. This so-called "dither" noise was later introduced in an entirely different context at the advent of digital information transmission and recording in the early 1960s. Ironically, the addition of noise allows one to preserve information that would otherwise be lost when the signal or image is digitized. As we shall see, the benefits of added noise in these contexts are closely related to the phenomenon which has come to be known as stochastic resonance, the original version of which appealed to noise to explain how small periodic fluctuations in the eccentricity of the earth's orbit might be amplified in such a way as to bring about the observed periodic transiti...

  12. Airport noise and teratogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Edmonds, L.D.; Layde, P.M.; Erickson, J.D.

    1979-07-01

    It has been suggested that exposure to high-noise levels near major airports may cause increased incidence of birth defects in the offspring of parents residing near these airports. Using data gathered in Metropolitan Atlanta during 1970 to 1972, we compared the rates of seventeen categories of defects in high- and low-noise census tracts. No significant differences were observed. However, when we subdivided the category of central nervous system defects into several subcategories of specific defects, we noted a significantly increased incidence of spina bifida without hydrocephalus in the high-noise areas. Because of the small number of cases associated with this finding we did a matched case-control study using all cases of central nervous system defects born during the years 1968 to 1976. No significantly increased risk for residents in the high-noise areas was noted in this study. It is our opinion that noise or other factors associated with residence near airports are unlikely to be important environmental teratogens.

  13. Optimal Correlation Filters for Images with Signal-Dependent Noise

    Science.gov (United States)

    Downie, John D.; Walkup, John F.

    1994-01-01

    We address the design of optimal correlation filters for pattern detection and recognition in the presence of signal-dependent image noise sources. The particular examples considered are film-grain noise and speckle. Two basic approaches are investigated: (1) deriving the optimal matched filters for the signal-dependent noise models and comparing their performances with those derived for traditional signal-independent noise models and (2) first nonlinearly transforming the signal-dependent noise to signal-independent noise followed by the use of a classical filter matched to the transformed signal. We present both theoretical and computer simulation results that demonstrate the generally superior performance of the second approach in terms of the correlation peak signal-to-noise ratio.

  14. Adaptive noise reduction circuit for a sound reproduction system

    Science.gov (United States)

    Engebretson, A. Maynard (Inventor); O'Connell, Michael P. (Inventor)

    1995-01-01

    A noise reduction circuit for a hearing aid having an adaptive filter for producing a signal which estimates the noise components present in an input signal. The circuit includes a second filter for receiving the noise-estimating signal and modifying it as a function of a user's preference or as a function of an expected noise environment. The circuit also includes a gain control for adjusting the magnitude of the modified noise-estimating signal, thereby allowing for the adjustment of the magnitude of the circuit response. The circuit also includes a signal combiner for combining the input signal with the adjusted noise-estimating signal to produce a noise reduced output signal.

  15. Analysis of the Noise Characteristics of CMOS Current Conveyors

    DEFF Research Database (Denmark)

    Bruun, Erik

    1997-01-01

    The definition of the current conveyor is reviewed and a multiple-output second generation current conveyor (CCII) is shown to combine the different generations of current conveyors presently existing. Next, noise sources are introduced, and a general noise model for the current conveyor...... is described. This model is used for the analysis of selected examples of current conveyor based operational amplifier configurations and the noise performance of these configurations is compared. Finally, the noise model is developed for a CMOS current conveyor implementation, and approaches...... to an optimization of the noise performance are discussed. It is concluded that a class AB implementation can yield a lower noise output for the same dynamic range than a class A implementation. For both the class A implementation and the class AB implementation it is essential to design low noise current mirrors...

  16. Vibration and noise analysis of a gear transmission system

    Science.gov (United States)

    Choy, F. K.; Qian, W.; Zakrajsek, J. J.; Oswald, F. B.

    1993-01-01

    This paper presents a comprehensive procedure to predict both the vibration and noise generated by a gear transmission system under normal operating conditions. The gearbox vibrations were obtained from both numerical simulation and experimental studies using a gear noise test rig. In addition, the noise generated by the gearbox vibrations was recorded during the experimental testing. A numerical method was used to develop linear relationships between the gearbox vibration and the generated noise. The hypercoherence function is introduced to correlate the nonlinear relationship between the fundamental noise frequency and its harmonics. A numerical procedure was developed using both the linear and nonlinear relationships generated from the experimental data to predict noise resulting from the gearbox vibrations. The application of this methodology is demonstrated by comparing the numerical and experimental results from the gear noise test rig.

  17. Underwater Noise Modeling in Lithuanian Area of the Baltic Sea

    Directory of Open Access Journals (Sweden)

    Donatas Bagočius

    2017-09-01

    Full Text Available Along with rising awareness of public and scientific societies about environmental and ecological impacts of underwater noise, the need for underwater noise modelling in the shallow Lithuanian area of Baltic Sea emerged. Marine Strategy Framework Directive issues regarding underwater noise indicators refers to possibility of evaluation of Good Environmental State using underwater noise measurements as well as possibility to model underwater noise. Main anthropogenic underwater noise contributor in the Seas is the shipping lanes as known due to date, with no exclusion of Lithuanian Baltic Sea area. In this manuscript, it is presented the methods of development of simplistic underwater ambient noise model purposed for computation of underwater soundscape in shallow area of the Lithuanian Baltic Sea.

  18. Cardiovascular effects of environmental noise: Research in Sweden

    Directory of Open Access Journals (Sweden)

    Gösta Bluhm

    2011-01-01

    Full Text Available In Sweden, as in many other European countries, traffic noise is an important environmental health issue. At present, almost two million people are exposed to average noise levels exceeding the outdoor national guideline value (55 dB(A. Despite efforts to reduce the noise burden, noise-related health effects, such as annoyance and sleep disturbances, are increasing. The scientific interest regarding more serious health effects related to the cardiovascular system is growing, and several experimental and epidemiological studies have been performed or are ongoing. Most of the studies on cardiovascular outcomes have been related to noise from road or aircraft traffic. Few studies have included railway noise. The outcomes under study include morning saliva cortisol, treatment for hypertension, self-reported hypertension, and myocardial infarction. The Swedish studies on road traffic noise support the hypothesis of an association between long-term noise exposure and cardiovascular disease. However, the magnitude of effect varies between the studies and has been shown to depend on factors such as sex, number of years at residence, and noise annoyance. Two national studies have been performed on the cardiovascular effects of aircraft noise exposure. The first one, a cross-sectional study assessing self-reported hypertension, has shown a 30% risk increase per 5 dB(A noise increase. The second one, which to our knowledge is the first longitudinal study assessing the cumulative incidence of hypertension, found a relative risk (RR of 1.10 (95% CI 1.01 - 1.19 per 5 dB(A noise increase. No associations have been found between railway noise and cardiovascular diseases. The findings regarding noise-related health effects and their economic consequences should be taken into account in future noise abatement policies and community planning.

  19. Conduction invasion noise in nanoparticle WO3/Au thin-film devices for gas sensing applicationThis paper is a slightly modified version of one presented at BioMEMS and Smart Nanostructures, SPIE Conference, Adelaide, Australia, 17-19 December 2001.

    Science.gov (United States)

    Hoel, A.; Ederth, J.; Kopniczky, J.; Heszler, P.; Kish, L. B.; Olsson, E.; Granqvist, C. G.

    2002-10-01

    Conduction noise measurements were carried out in the 0.3-45 Hz frequency range on Au films covered by a thin layer of tungsten trioxide (WO3) nanoparticles. Exposing the films to alcohol vapor resulted in a gradually increased noise intensity which went through a maximum after an exposure time of the order of 15 min. The maximum noise intensity could increase by several orders of magnitude above the initial level. Longer exposure times made the noise decrease and approach its original value. This effect was not observed in the absence of WO3 nanoparticles. The phenomenon is discussed in terms of a new 'invasion noise' model in which the noise is related to the insertion and extraction of mobile chemical species.

  20. Perturbation Solutions for Random Linear Structural Systems subject to Random Excitation using Stochastic Differential Equations

    DEFF Research Database (Denmark)

    Köyluoglu, H.U.; Nielsen, Søren R.K.; Cakmak, A.S.

    1994-01-01

    The paper deals with the first and second order statistical moments of the response of linear systems with random parameters subject to random excitation modelled as white-noise multiplied by an envelope function with random parameters. The method of analysis is basically a second order perturbat......The paper deals with the first and second order statistical moments of the response of linear systems with random parameters subject to random excitation modelled as white-noise multiplied by an envelope function with random parameters. The method of analysis is basically a second order...... for multi-degree-of-freedom (MDOF) systems and the method is illustrated for a single-degree-of-freedom (SDOF) oscillator. The results are compared to those of exact results for a random oscillator subject to white noise excitation with random intensity....

  1. Noise Hazard Evaluation Sound Level Data on Noise Sources

    Science.gov (United States)

    1975-01-01

    Doo 300, Snowmobile 90 80. Ski -Doo Alpine 399 ER, Snovnnobile 80 81. Ski -Doo Elan, Sno.mobil-e 80 82. Ski -Doo Nordic 375, Snowmobile 86 83. Ski -Doo...ACCESION NO. 3. RECIPIENT’S CATALOG NUMBER 4. TITLE (and Subtitae) 5. TYPE OF REPORT & PERIOD COVERED NOISE HAZARD EVALUATION, SOUND LEVEL DATA OF...are not practically suitable to the threshold criterion presented in paragraph III B. 3. Winen the daily exposure is composed of two or more periods of

  2. Road Traffic Noise

    Science.gov (United States)

    Beckenbauer, Thomas

    Road traffic is the most interfering noise source in developed countries. According to a publication of the European Union (EU) at the end of the twentieth century [1], about 40% of the population in 15 EU member states is exposed to road traffic noise at mean levels exceeding 55 dB(A). Nearly 80 million people, 20% of the population, are exposed to levels exceeding 65 dB(A) during daytime and more than 30% of the population is exposed to levels exceeding 55 dB(A) during night time. Such high noise levels cause health risks and social disorders (aggressiveness, protest, and helplessness), interference of communication and disturbance of sleep; the long- and short-term consequences cause adverse cardiovascular effects, detrimental hormonal responses (stress hormones), and possible disturbance of the human metabolism (nutrition) and the immune system. Even performance at work and school could be impaired.

  3. Noise and Tinnitus

    Directory of Open Access Journals (Sweden)

    Mansoureh Adel Ghahraman

    1999-03-01

    Full Text Available Tinnitus from the Latin word tinnire meaning ringing is the perception of sound within the human ear in the absence of corresponding external sound. The most common cause is noise induced hearing loss. Tinnitus may be induced by an acoustic trauma or a permanent noise in the workplace. In case that Tinnitus is induced by acoustic trauma the site of lesion is commonly the base of the cochlea. Tinnitus in the senile population is mostly accompanying presbycusis. Although the incidence of permanent tinnitus following noise exposure is high, little is published about this issue. In the current article we are aimed at studying the prevalence of tinnitus in Minoo and other manufactures.

  4. Noise considerations in the development of coalbed methane

    Energy Technology Data Exchange (ETDEWEB)

    DeGagne, D.C. [Noise Solutions Inc., Calgary, AB (Canada); Burke, D. [Energy Resources Conservation Board, Calgary, AB (Canada)

    2009-07-01

    Since coalbed methane (CBM) development remains a secure option for meeting energy demands, industry will need to deal effectively with noise to reduce landowner concerns. This paper presented lessons learned and case histories for the successful approach to noise solutions accepted by regulatory agencies and industry clients. The complexities of acoustical engineering practices were discussed along with the most significant points to meeting regulatory requirements for environmental noise as stated in the Energy Resources Conservation Board (ERCB) Directive 038. The focus of the paper was on the management of environmental noise that will affect nearby residents. Noise is generally viewed as one of a number of general biological stressors. Although there is no health risk from short term exposure to noise, excessive exposure to noise might be considered a health risk as noise may contribute to the development of stress related conditions. Sleep disturbance is the most significant contributor to a stress response due to annoyance from industrial noise. This presentation demonstrated that environmental noise can be managed efficiently and in a cost effective manner. Noise control technology allows companies to meet nearly any level of noise control necessary to be in compliance with regulations. The following are commonly used in CBM operations: noise impact assessments; engine exhaust silencers; cooler silencers; acoustical buildings; building ventilation; and landscape friendly buildings. It was concluded that companies that invest in state of the art noise control combined with a stakeholder consultation program that respects the community's needs and concerns will be able to operate harmoniously with both regulators and community residents. 49 refs., 3 tabs., 4 figs.

  5. Does health promotion work in relation to noise?

    Science.gov (United States)

    Borchgrevink, H M

    2003-01-01

    Noise is a health risk. The only scientifically established adverse health effect of noise is noise-induced hearing loss (NIHL). Besides noise may affect quality of life and cause annoyance and sleep disturbance. The present scientific evidence of potential non-auditory effects of noise on health is quite weak. Whether health promotion works in relation to noise may be reflected by permanent hearing threshold shift development in population studies. Hearing impairment continues to be the most prevalent disability in Western societies. The National Institute of Occupational Safety and Health (NIOSH) still rates noise induced hearing loss among the top ten work-related problems. Recent studies report that employees continue to develop noise induced hearing loss although to a lesser extent than before, in spite of occupational hearing conservation programmes. Besides socio-acusis and leisure noise seem to be an increasing hazard to hearing, also in young children and adolescents. This seems partly related to acute leisure noise exposure (e.g. toy pistols, amplified music). However, population studies increasingly find non-normal high-frequency hearing including the characteristic NIHL-"notch" around 6 kHz also in subjects who do not report noise exposure incidents or activities. Today 12.5% of US children 6-19 years show a noise-"notch" in one or both ears (n= 5249, Niskar et al 2001). A Norwegian county audiometry survey on adults >/= 20 years n=51.975) showed mean unscreened thresholds +10 dB at 6 kHz for both genders even or the youngest age group 20-24 years (Borchgrevink et al 2001). Accordingly, the present health promotion initiatives seem insufficient in relation to noise and noise-induced hearing loss.

  6. Noise and Vibration Mitigation for Rail Transportation Systems : Proceedings of the 10th International Workshop on RailwayNoise

    CERN Document Server

    Gautier, Pierre-Etienne; Hanson, Carl; Hemsworth, Brian; Nelson, James; Schulte-Werning, Burkhard; Thompson, David; Vos, Paul

    2012-01-01

    This volume contains the contributions to the 10th International Workshop on Railway Noise, held October 18–22, 2010, in Nagahama, Japan, organized by the Railway Technical Research Institute (RTRI), Japan. With 11 sessions and 3 poster sessions, the workshop featured presentations by international leaders in the field of railway noise and vibration. All subjects relating to 1. prospects, legal regulation, and perception; 2. wheel and rail noise; 3. structure-borne noise and squeal noise; 4. ground-borne vibration; 5. aerodynamic noise and micro-pressure waves from tunnel portals; 6. interior noise and sound barriers; and 7. prediction, measurements, and monitoring are addressed here. This book is a useful “state-of-the-art” reference for scientists and engineers involved in solving environmental problems of railways.

  7. [Noise--a stress factor in occupational and other environments].

    Science.gov (United States)

    Zober, A

    1984-03-01

    The effects of noise on health can be divided into aural effects and extraaural effects. The following review describes - after some historical remarks - first the physical and technical basis of noise analysis. The definition of "equivalent continuous sound level" (Lm) and "rating sound level" (Lr) is given. Extraaural noise effects mainly come from the environment (traffic noise, construction noise on building sites). One must distinguish physical and vegetative reactions. An important extraaural effect is the disturbance of sleep. The objectivation and quantification of extraaural effects of noise on health is very difficult because there exist a lot of disturbing factors. The most important aural effect of noise on health is the occupational hearing loss. To assess these effects, information about physiology, pathophysiology and clinical indications of noise induced labyrinthine deafness is necessary. As examples results of investigations into the effect of noise on arc welders, professional musicians and building workers are presented. Generation of noise should be minimised by technical methods, exposure to noise by personal protection. The methods for occupational medical check-up of the employment accident insurance fund are specially mentioned. The results of these preventive procedures can be seen in the decreasing numbers of occupational hearing loss.

  8. CONTROLLING RISK DUE TO NOISE ON FERRY BOAT

    Directory of Open Access Journals (Sweden)

    Aleksandar Nikolic

    2013-07-01

    Full Text Available Environmental and occupational noise is common nuisance that affects the health of employees. Performed health checks of employees engaged by Company “Pomorski Saobraćaj” showed that 5% of examined sailors had hearing loss. The results were a trigger for starting experiment on noise risk assessment with objective to discover possibilities of noise pollution presence, precise significant noise sources and describe solutions for eliminating negative effects. Several measurements on five positions were performed on ferry boat “KAMENARI”, according to EC Physical Agents Directive and Merchant Shipping and Fishing Vessels Regulations 2007. Noise on selected positions exceeded the limit for about 1-5dB. Noise exposure level was 84.5dB. Diesel engine, exhaust system and structural noise were main sources of excessive noise. Experiment shows noise presence as nuisance that affects sailors. Noise presents a serious threat for sailor’s health. It interferes with crew communication and jeopardizes navigation safety. Technical measures, crew health checks and noise monitoring could prevent all negative effects.

  9. Block randomization versus complete randomization of human perception stimuli: is there a difference?

    Science.gov (United States)

    Moyer, Steve; Uhl, Elizabeth R.

    2015-05-01

    For more than 50 years, the U.S. Army RDECOM CERDEC Night Vision and Electronic Sensors Directorate (NVESD) has been studying and modeling the human visual discrimination process as it pertains to military imaging systems. In order to develop sensor performance models, human observers are trained to expert levels in the identification of military vehicles. From 1998 until 2006, the experimental stimuli were block randomized, meaning that stimuli with similar difficulty levels (for example, in terms of distance from target, blur, noise, etc.) were presented together in blocks of approximately 24 images but the order of images within the block was random. Starting in 2006, complete randomization came into vogue, meaning that difficulty could change image to image. It was thought that this would provide a more statistically robust result. In this study we investigated the impact of the two types of randomization on performance in two groups of observers matched for skill to create equivalent groups. It is hypothesized that Soldiers in the Complete Randomized condition will have to shift their decision criterion more frequently than Soldiers in the Block Randomization group and this shifting is expected to impede performance so that Soldiers in the Block Randomized group perform better.

  10. Community response to noise

    Directory of Open Access Journals (Sweden)

    Takashi Yano

    2012-01-01

    Full Text Available Activities from 2008 to 2011 by ICBEN community response to noise team were summarized. That is, individual community-based indexes such as community tolerance Level, Zuricher Fluglarm Index (ZFI and Frankfurter Fluglarm Index (FFI/FNI were newly proposed, differences in railway bonus between Europe and Asia were discussed by a Swedish survey, socio-acoustic surveys were reported from developing countries, and annoyance equivalents and dominant source models were proposed as the adequate combined noise model. Furthermore, not only negative, but also positive aspects of sound were discussed as soundscape studies. Finally, seven items were listed as future team activities.

  11. Noise Source Location Optimization

    Directory of Open Access Journals (Sweden)

    Ed O’Keefe

    1994-01-01

    Full Text Available This article describes a method to determine locations of noise sources that minimize modal coupling in complex acoustic volumes. Using the acoustic source scattering capabilities of the boundary element method, predictions are made of mode shape and pressure levels due to various source locations. Combining knowledge of the pressure field with a multivariable function minimization technique, the source location generating minimum pressure levels can be determined. The analysis also allows for an objective comparison of “best/worst” locations. The technique was implemented on a personal computer for the U.S. Space Station, predicting 5–10 dB noise reduction using optimum source locations.

  12. Jet Engine Noise Reduction

    Science.gov (United States)

    2009-04-01

    all of these noise sources. 6 777-200 A330-300 MD-90-30 MD-11 A320-214 747-400 A300-600R 767-300ER 757 -200 MD-87 MD-82 B-747-300 A300B4-620...broadband shock noise; fluidic/particulate injection; flexible filaments (i.e., wires attached to the nozzle or tail cone ); offset nozzles to reduce...the introduction of the turbojet engine powered Boeing 707 beginning in 1958. Following a series of lawsuits in the United States and public outcry

  13. Introductory guide to noise

    CSIR Research Space (South Africa)

    Ferreira, T.M

    1973-01-01

    Full Text Available GepteMehek. WHY IS NOISE SO Our ears are used primarily to communicate with others. to give warning of danger and to absorb sensory pleasures such as from music. The degree of irritation is related to the extent to which a sound interferes with these uses... on aircraft that make too much noise. Motor cars, buses, buzz-bikes and vacuum deaners can be effectively quietened but until now the public has not been prepared to pay the price of legislation. Also, many young sports-car enthusiasts still think...

  14. Accurate estimation of camera shot noise in the real-time

    Science.gov (United States)

    Cheremkhin, Pavel A.; Evtikhiev, Nikolay N.; Krasnov, Vitaly V.; Rodin, Vladislav G.; Starikov, Rostislav S.

    2017-10-01

    Nowadays digital cameras are essential parts of various technological processes and daily tasks. They are widely used in optics and photonics, astronomy, biology and other various fields of science and technology such as control systems and video-surveillance monitoring. One of the main information limitations of photo- and videocameras are noises of photosensor pixels. Camera's photosensor noise can be divided into random and pattern components. Temporal noise includes random noise component while spatial noise includes pattern noise component. Temporal noise can be divided into signal-dependent shot noise and signal-nondependent dark temporal noise. For measurement of camera noise characteristics, the most widely used methods are standards (for example, EMVA Standard 1288). It allows precise shot and dark temporal noise measurement but difficult in implementation and time-consuming. Earlier we proposed method for measurement of temporal noise of photo- and videocameras. It is based on the automatic segmentation of nonuniform targets (ASNT). Only two frames are sufficient for noise measurement with the modified method. In this paper, we registered frames and estimated shot and dark temporal noises of cameras consistently in the real-time. The modified ASNT method is used. Estimation was performed for the cameras: consumer photocamera Canon EOS 400D (CMOS, 10.1 MP, 12 bit ADC), scientific camera MegaPlus II ES11000 (CCD, 10.7 MP, 12 bit ADC), industrial camera PixeLink PL-B781F (CMOS, 6.6 MP, 10 bit ADC) and video-surveillance camera Watec LCL-902C (CCD, 0.47 MP, external 8 bit ADC). Experimental dependencies of temporal noise on signal value are in good agreement with fitted curves based on a Poisson distribution excluding areas near saturation. Time of registering and processing of frames used for temporal noise estimation was measured. Using standard computer, frames were registered and processed during a fraction of second to several seconds only. Also the

  15. Point process analysis of noise in early invertebrate vision.

    Directory of Open Access Journals (Sweden)

    Kris V Parag

    2017-10-01

    Full Text Available Noise is a prevalent and sometimes even dominant aspect of many biological processes. While many natural systems have adapted to attenuate or even usefully integrate noise, the variability it introduces often still delimits the achievable precision across biological functions. This is particularly so for visual phototransduction, the process responsible for converting photons of light into usable electrical signals (quantum bumps. Here, randomness of both the photon inputs (regarded as extrinsic noise and the conversion process (intrinsic noise are seen as two distinct, independent and significant limitations on visual reliability. Past research has attempted to quantify the relative effects of these noise sources by using approximate methods that do not fully account for the discrete, point process and time ordered nature of the problem. As a result the conclusions drawn from these different approaches have led to inconsistent expositions of phototransduction noise performance. This paper provides a fresh and complete analysis of the relative impact of intrinsic and extrinsic noise in invertebrate phototransduction using minimum mean squared error reconstruction techniques based on Bayesian point process (Snyder filters. An integrate-fire based algorithm is developed to reliably estimate photon times from quantum bumps and Snyder filters are then used to causally estimate random light intensities both at the front and back end of the phototransduction cascade. Comparison of these estimates reveals that the dominant noise source transitions from extrinsic to intrinsic as light intensity increases. By extending the filtering techniques to account for delays, it is further found that among the intrinsic noise components, which include bump latency (mean delay and jitter and shape (amplitude and width variance, it is the mean delay that is critical to noise performance. As the timeliness of visual information is important for real-time action, this

  16. The McKenzie method compared with manipulation when used adjunctive to information and advice in low back pain patients presenting with centralization or peripheralization. A randomized controlled trial

    DEFF Research Database (Denmark)

    Petersen, Tom; Larsen, Kristian; Nordsteen, Jan

    2011-01-01

    .018). The number needed to treat with the McKenzie-method was 7 (95% CI 4 to 47). The McKenzie group showed improvement in level of disability compared to the manipulation group reaching a statistical significance at two and twelve months follow-up (mean difference 1.5, 95% CI 0.2 to 2.8, P = 0.022 and 1.5, 95% CI......ABSTRACT: Study design. Randomized controlled trial.Objective. To compare the effects of the McKenzie-method performed by certified therapists with spinal manipulation performed by chiropractors when used adjunctive to information and advice.Summary of Background Data. Recent guidelines recommend...... for more than six weeks presenting with centralization or peripheralization of symptoms, we found the McKenzie method to be slightly more effective than manipulation when used adjunctive to information and advice....

  17. Psychoacoustic study on contribution of fan noise to engine noise

    Science.gov (United States)

    Zhang, Junhong; Liu, Hai; Bi, Fengrong; Ni, Guangjian; Zhang, Guichang; Lin, Jiewei; Yu, Hanzhengnan

    2012-07-01

    There are more researches on engine fan noise control focusing on reducing fan noise level through optimizing fan structure, and a lot of research achievements have been obtained. However, researches on the effect of fan noise to engine noise quality are lacking. The influences of the effects of fan structure optimization on the engine noise quality are unclear. Thus, there will be a decline in fan noise level, but the deterioration of engine noise quality. Aiming at the above problems, in consideration of fan structure design and engine noise quality, an innovative method to analyze the contribution of fan noise to engine noise quality using psychoacoustic theory is proposed. The noises of diesel engine installing different cooling fans are measured by using the acoustic pressure method. The experiment results are regarded as analysis samples. The model of sensory pleasantness is used to analyze the sound quality of a diesel engine with different cooling fans. Results show that after installing 10-blade fan in medium diameter the sensory pleasantness at each test point is increased, and the increase is 13.53% on average, which indicate the improvement of the engine noise quality. In order to verify the psychoacoustical analysis, the subjective assessment is carried out. The test result shows the noise quality of engine installed 10-blade fan in medium diameter is most superior. 1/3 octave frequency spectrum analysis is used to study the reason of the improvement of engine noise quality. It is found that after installing proper cooling fan the sound pressure level below 400 Hz are obviously increased, the frequency assignment and spectral envelope are more reasonable and a proper cooling fan can optimize the spectrum structure of the engine noise. The psychoacoustic study is applied in the contribution of fan noise to engine noise, and the idea of engine sound quality improvement through the structure optimization is proposed.

  18. Toddlers' recognition of noise-vocoded speech

    Science.gov (United States)

    Newman, Rochelle; Chatterjee, Monita

    2013-01-01

    Despite their remarkable clinical success, cochlear-implant listeners today still receive spectrally degraded information. Much research has examined normally hearing adult listeners' ability to interpret spectrally degraded signals, primarily using noise-vocoded speech to simulate cochlear implant processing. Far less research has explored infants' and toddlers' ability to interpret spectrally degraded signals, despite the fact that children in this age range are frequently implanted. This study examines 27-month-old typically developing toddlers' recognition of noise-vocoded speech in a language-guided looking study. Children saw two images on each trial and heard a voice instructing them to look at one item (“Find the cat!”). Full-spectrum sentences or their noise-vocoded versions were presented with varying numbers of spectral channels. Toddlers showed equivalent proportions of looking to the target object with full-speech and 24- or 8-channel noise-vocoded speech; they failed to look appropriately with 2-channel noise-vocoded speech and showed variable performance with 4-channel noise-vocoded speech. Despite accurate looking performance for speech with at least eight channels, children were slower to respond appropriately as the number of channels decreased. These results indicate that 2-yr-olds have developed the ability to interpret vocoded speech, even without practice, but that doing so requires additional processing. These findings have important implications for pediatric cochlear implantation. PMID:23297920

  19. Nonlinear biochemical signal processing via noise propagation.

    Science.gov (United States)

    Kim, Kyung Hyuk; Qian, Hong; Sauro, Herbert M

    2013-10-14

    Single-cell studies often show significant phenotypic variability due to the stochastic nature of intra-cellular biochemical reactions. When the numbers of molecules, e.g., transcription factors and regulatory enzymes, are in low abundance, fluctuations in biochemical activities become significant and such "noise" can propagate through regulatory cascades in terms of biochemical reaction networks. Here we develop an intuitive, yet fully quantitative method for analyzing how noise affects cellular phenotypes based on identifying a system's nonlinearities and noise propagations. We observe that such noise can simultaneously enhance sensitivities in one behavioral region while reducing sensitivities in another. Employing this novel phenomenon we designed three biochemical signal processing modules: (a) A gene regulatory network that acts as a concentration detector with both enhanced amplitude and sensitivity. (b) A non-cooperative positive feedback system, with a graded dose-response in the deterministic case, that serves as a bistable switch due to noise-induced ultra-sensitivity. (c) A noise-induced linear amplifier for gene regulation that requires no feedback. The methods developed in the present work allow one to understand and engineer nonlinear biochemical signal processors based on fluctuation-induced phenotypes.

  20. Ultra Low Noise Poroelastic Road Surfaces

    Directory of Open Access Journals (Sweden)

    Jerzy A. Ejsmont

    2016-04-01

    Full Text Available Noise is one of the most important environmental problems related to road traffic. During the last decades, the noise emitted by the engines and powertrains of vehicles was greatly reduced and tires became a clearly dominant noise source. The article describes the concept of low noise poroelastic road surfaces that are composed of mineral and rubber aggregate bound by polyurethane resin. Those surfaces have a porous structure and are much more flexible than standard asphalt or cement concrete pavements due to high content of rubber aggregate and elastic binder. Measurements performed in several European countries indicate that such surfaces decrease tire/road noise between 7 dB and 12 dB with respect to reference surfaces such as dense asphalt concrete or stone matrix asphalt. Furthermore, poroelastic road surfaces ascertain the rolling resistance of car tires, which is comparable to classic pavements. One of the unforeseen properties of the poroelastic road surfaces is their ability to decrease the risks related to car fires with fuel spills. The article presents the road and laboratory results of noise, rolling resistance, and fire tests performed on a few types of poroelastic road surfaces.

  1. Effect of external classroom noise on schoolchildren's reading and mathematics performance: correlation of noise levels and gender.

    Science.gov (United States)

    Papanikolaou, M; Skenteris, N; Piperakis, S M

    2015-02-01

    The present study investigated the effect of low, medium, and high traffic road noise as well as irrelevant background speech noise on primary school children's reading and mathematical performance. A total of 676 participants (324 boys, 47.9% and 352 girls, 52.1%) of the 4th and 5th elementary classes participated in the project. The participants were enrolled in public primary schools from urban areas and had ages ranging from 9 to 10 years and from. Schools were selected on the basis of increasing levels of exposure to road traffic noise and then classified into three categories (Low noise: 55-66 dB, Medium noise: 67-77 dB, and High noise: 72-80 dB). We measured reading comprehension and mathematical skills in accordance with the national guidelines for elementary education, using a test designed specifically for the purpose of this study. On the one hand, children in low-level noise schools showed statistically significant differences from children in medium- and high-level noise schools in reading performance (pschools differed significantly from children in high-level noise schools but only in mathematics performance (p=0.001). Girls in general did better in reading score than boys, especially in schools with medium- and high-level noise. Finally the levels of noise and gender were found to be two independent factors.

  2. Noise exposure and hearing impairment among Chinese restaurant workers and entertainment employees in Hong Kong.

    Directory of Open Access Journals (Sweden)

    Xiang Qian Lao

    Full Text Available BACKGROUND: Noise-induced hearing loss (NIHL is a major concern in the non-manufacturing industries. This study aimed to investigate the occupational noise exposure and the NIHL among Chinese restaurant workers and entertainment employees working in the service industry in Hong Kong. METHODS: This cross-sectional survey involved a total of 1,670 participants. Among them, 937 were randomly selected from the workers of Chinese restaurants and 733 were selected from workers in three entertainment sectors: radio and television stations; cultural performance halls or auditoria of the Leisure and Cultural Services Department (LCSD; and karaoke bars. Noise exposure levels were measured in the sampled restaurants and entertainment sectors. Each participant received an audiometric screening test. Those who were found to have abnormalities were required to take another diagnostic test in the health center. The "Klockhoff digit" method was used to classify NIHL in the present study. RESULTS: The main source of noise inside restaurants was the stoves. The mean hearing thresholds showed a typical dip at 3 to 6 KHz and a substantial proportion (23.7% of the workers fulfilled the criteria for presumptive NIHL. For entertainment sectors, employees in radio and television stations generally had higher exposure levels than those in the halls or auditoria of the LCSD and karaoke bars. The mean hearing thresholds showed a typical dip at 6 KHz and a substantial proportion of the employees fulfilled the criteria for presumptive NIHL (38.6%, 95%CI: 35.1-42.1%. Being male, older, and having longer service and daily alcohol consumption were associated with noise-induced hearing impairment both in restaurant workers and entertainment employees. CONCLUSION: Excessive noise exposure is common in the Chinese restaurant and entertainment industries and a substantial proportion of restaurant workers and entertainment employees suffer from NIHL. Comprehensive hearing

  3. Effect of Ascorbic Acid on Noise Induced Hearing Loss in Rats

    Directory of Open Access Journals (Sweden)

    Ziba Loukzadeh

    2015-07-01

    Full Text Available Introduction: After presbycusis, noise-induced hearing loss is the second most common cause of acquired hearing loss. Numerous studies have shown that high-intensity noise exposure increases free radical species; therefore, use of antioxidants to detoxify the free radicals can prevent cellular damage in the cochlea. We studied the potential hearing protective effect of different doses of ascorbic acid administered prior to noise exposure in rats.   Materials and Methods: Twenty-four male albino Wistar rats were randomly allocated into four groups: groups A, B, and C received 1250, 250, and 50 mg/kg/day of ascorbic acid, respectively, and group D acted as the control group. After 14 days of ascorbic acid administration, the rats were exposed to noise (105 dB sound pressure level for 2 h. Distortion product otoacoustic emissions (DPOAE were recorded prior to starting the ascorbic acid as baseline and 1 h after the noise exposure.   Results: The amplitude decrease was 14.99 dB for group A, 16.11 dB for group B, 28.82 dB for group C, and 29.91 dB for the control group. Moderate and high doses of ascorbic acid significantly reduced the transient threshold shift in the rats.   Conclusion:  The results of present study support the concept of cochlea protection by antioxidant agents. This dose-dependent protective effect was shown through the use of ascorbic acid treatment prior to noise exposure.

  4. Noise exposure and hearing impairment among Chinese restaurant workers and entertainment employees in Hong Kong.

    Science.gov (United States)

    Lao, Xiang Qian; Yu, Ignatius Tak Sun; Au, Dennis Kin Kwok; Chiu, Yuk Lan; Wong, Claudie Chiu Yi; Wong, Tze Wai

    2013-01-01

    Noise-induced hearing loss (NIHL) is a major concern in the non-manufacturing industries. This study aimed to investigate the occupational noise exposure and the NIHL among Chinese restaurant workers and entertainment employees working in the service industry in Hong Kong. This cross-sectional survey involved a total of 1,670 participants. Among them, 937 were randomly selected from the workers of Chinese restaurants and 733 were selected from workers in three entertainment sectors: radio and television stations; cultural performance halls or auditoria of the Leisure and Cultural Services Department (LCSD); and karaoke bars. Noise exposure levels were measured in the sampled restaurants and entertainment sectors. Each participant received an audiometric screening test. Those who were found to have abnormalities were required to take another diagnostic test in the health center. The "Klockhoff digit" method was used to classify NIHL in the present study. The main source of noise inside restaurants was the stoves. The mean hearing thresholds showed a typical dip at 3 to 6 KHz and a substantial proportion (23.7%) of the workers fulfilled the criteria for presumptive NIHL. For entertainment sectors, employees in radio and television stations generally had higher exposure levels than those in the halls or auditoria of the LCSD and karaoke bars. The mean hearing thresholds showed a typical dip at 6 KHz and a substantial proportion of the employees fulfilled the criteria for presumptive NIHL (38.6%, 95%CI: 35.1-42.1%). Being male, older, and having longer service and daily alcohol consumption were associated with noise-induced hearing impairment both in restaurant workers and entertainment employees. Excessive noise exposure is common in the Chinese restaurant and entertainment industries and a substantial proportion of restaurant workers and entertainment employees suffer from NIHL. Comprehensive hearing conservation programs should be introduced to the service industry

  5. Delivery presentations

    Science.gov (United States)

    ... is delivered under the pubic bone. After the shoulder, the rest of the body is usually delivered without a problem. Alternative Names Shoulder presentation; Malpresentations; Breech birth; Cephalic presentation; Fetal lie; ...

  6. Ultra-low-noise microwave amplifiers

    Science.gov (United States)

    Clauss, R. C.; Trowbridge, D.

    1980-01-01

    The highlights of 20 years of maser use and development are presented. Masers discussed include cavity, traveling wave, K band, and S band. Noise temperatures measured since 1960 are summarized. Use of masers in the Deep Space Network is presented. Costs associated with the construction of masers systems are given.

  7. Random matrices

    CERN Document Server

    Mehta, Madan Lal

    1990-01-01

    Since the publication of Random Matrices (Academic Press, 1967) so many new results have emerged both in theory and in applications, that this edition is almost completely revised to reflect the developments. For example, the theory of matrices with quaternion elements was developed to compute certain multiple integrals, and the inverse scattering theory was used to derive asymptotic results. The discovery of Selberg's 1944 paper on a multiple integral also gave rise to hundreds of recent publications. This book presents a coherent and detailed analytical treatment of random matrices, leading

  8. Infrasound and low frequency noise assessment at workplaces and environment – review of criteria

    Directory of Open Access Journals (Sweden)

    Krystyna Pawlas

    2013-03-01

    Full Text Available Infrasound and low frequency noise assessment at workplaces and environment - review of criteria Number of anthropogenic sources of infrasounds and low frequency noise is increasing, therefore it is followed by both increasing exposure level and number of persons exposed to this noise. Criteria of low frequency noise assessment is one of the problem needed to be solved. The paper presents existing polish and international criteria of assessment low frequency noise at workplaces and human settings

  9. Road Traffic Noise - A study of region Skåne, Sweden

    OpenAIRE

    Farcas, Florentina

    2008-01-01

    Since the first car appeared, the pollution on the roads became an issue, which is still mainly unsolved. Too many people complain about traffic noise. Various methods have been developed that aimed at minimizing the noise pollution and improving the environment. This thesis presents the problems posed by noise pollution, covers the background of noise pollution and its effects on human health. Another important part of the thesis covers the method of noise calculation which applies in specif...

  10. Urban form indicators as proxy on the noise exposure of buildings

    OpenAIRE

    Silva, Lígia Torres; Oliveira, Marta Isabela Fernandes; Silva, José F.

    2014-01-01

    Available online 27 September 2013 The present paper aims to address the problems of the urban environment as an area of interaction between urban forms and urban noise. This interaction is intended to be monitored using urban indica-tors, by comparing the effects of noise propagation using models of urban forms. The model of noise pre-diction allowed developing noise studies in facades, resulting in noise levels in a calculation grid located in the building facades. The study will a...

  11. Effect of spatial charge inhomogeneity on 1/f noise behavior in graphene.

    Science.gov (United States)

    Xu, Guangyu; Torres, Carlos M; Zhang, Yuegang; Liu, Fei; Song, Emil B; Wang, Minsheng; Zhou, Yi; Zeng, Caifu; Wang, Kang L

    2010-09-08

    Scattering mechanisms in graphene are critical to understanding the limits of signal-to-noise ratios of unsuspended graphene devices. Here we present the four-probe low-frequency noise (1/f) characteristics in back-gated single layer graphene (SLG) and bilayer graphene (BLG) samples. Contrary to the expected noise increase with the resistance, the noise for SLG decreases near the Dirac point, possibly due to the effects of the spatial charge inhomogeneity. For BLG, a similar noise reduction near the Dirac point is observed, but with a different gate dependence of its noise behavior. Some possible reasons for the different noise behavior between SLG and BLG are discussed.

  12. Psychoacoustic considerations for helicopter noise quantification: Metrics, human response and criteria

    Science.gov (United States)

    Powell, C. A.

    1982-01-01

    The purpose of this paper is to examine several aspects of helicopter noise quantification from the standpoint of psychoacoustics. Noise metrics in common use to describe far-field aircraft noise and the noise characteristics which they consider are discussed. Some findings of recent psychoacoustic research related specifically to helicopter noise quantification are presented. Criteria for the accuracy of noise metrics to quantify helicopter noise are discussed. Finally, the prospects for improved metrics and research needed to develop and validate improved metrics or existing metrics are discussed.

  13. Playback Experiments for Noise Exposure.

    Science.gov (United States)

    Holles, Sophie; Simpson, Stephen D; Lecchini, David; Radford, Andrew N

    2016-01-01

    Playbacks are a useful tool for conducting well-controlled and replicated experiments on the effects of anthropogenic noise, particularly for repeated exposures. However, playbacks are unlikely to fully reproduce original sources of anthropogenic noise. Here we examined the sound pressure and particle acceleration of boat noise playbacks in a field experiment and reveal that although there remain recognized limitations, the signal-to-noise ratios of boat playbacks to ambient noise do not exceed those of a real boat. The experimental setup tested is therefore of value for use in experiments on the effects of repeated exposure of aquatic animals to boat noise.

  14. Impulse Noise Injury Model.

    Science.gov (United States)

    Chan, Philemon; Ho, Kevin; Ryan, Allen F

    2016-05-01

    The new Auditory 4.0 model has been developed for the assessment of auditory outcomes, expressed as temporary threshold shift (TTS) and permanent threshold shift (PTS), from exposures to impulse noise for unprotected ears, including the prediction of TTS recovery. Auditory 4.0 is an empirical model, constructed from test data collected from chinchillas exposed to impulse noise in the laboratory. Injury outcomes are defined as TTS and PTS, and Auditory 4.0 provides the full range of TTS and PTS dose-response curves with the risk factor constructed from A-weighted sound exposure level. Human data from large weapons noise exposure was also used to guide the development of the recovery model. Guided by data, a 28-dBA shift was applied to the dose-response curves to account for the scaling from chinchillas to humans. Historical data from rifle noise tests were used to validate the dose-response curves. New chinchilla tests were performed to collect recovery data to construct the TTS recovery model. Auditory 4.0 is the only model known to date that provides the full TTS and PTS dose-response curves, including a TTS recovery model. The model shows good agreement with historical data. Reprint & Copyright © 2016 Association of Military Surgeons of the U.S.

  15. Noise: A Health Problem.

    Science.gov (United States)

    Environmental Protection Agency, Washington, DC. Office of Noise Abatement and Control.

    This booklet contains nine sections describing ways in which noise may endanger health and well-being. Secions are included on: (1) hearing loss; (2) heart disease; (3) other reactions by the body; (4) effects on the unborn; (5) special effects on children; (6) intrusion at home and work; (7) sleep disruption; (8) mental and social well-being; and…

  16. Low Noise Amplifiers

    Science.gov (United States)

    Petty, S. M.; Trowbridge, D. L.

    1983-01-01

    One of the great technical challenges facing the Deep Space Network is receiving signals from a severely weight limited spacecraft hundreds of thousands to billions of kilometers from Earth. This weight limitation has always imposed strict limitations on the size of the spacecraft antenna and the amount of transmitter power radiated. The communication burden is placed upon the ground systems of the Deep Space Network which must recover an extremely weak signal in the presence of nearly overwhelming amounts of noise. Two key parameters that determine the signal to noise ratio of a received signal using a deep space station are the collecting area and efficiency of the antenna, and the amount of noise which is generated in, as well as allowed to enter in, the antenna-mounted receiver. These parameters are used to describe the relative ability of a deep space station to receive weak signals. As spacecraft to Earth communication distances have increased, the Deep Space Network engages in a relentless effort to increase the figure of merit through larger and more efficient antennas, higher frequencies, and lower system noise temperature.

  17. Design of a solid state laser for low noise upconversion detection of near infrared light

    DEFF Research Database (Denmark)

    Høgstedt, Lasse; Tidemand-Lichtenberg, Peter; Pedersen, Christian

    2015-01-01

    To maximize signal-to-noise ratio for upconversion of near-infrared light we show that the mixing intensity should be 3 GW/m2. With emphasis on the noise contribution from random duty-cycle errors the optimum design parameters is discussed.......To maximize signal-to-noise ratio for upconversion of near-infrared light we show that the mixing intensity should be 3 GW/m2. With emphasis on the noise contribution from random duty-cycle errors the optimum design parameters is discussed....

  18. Social survey findings on en route noise annoyance issues

    Science.gov (United States)

    Fields, James M.

    1990-01-01

    Most surveys of residents' reactions to aircraft noise were conducted in the vicinity of airports. The findings in those surveys have supported planning and regulatory actions for the airport noise environment. Now, however, aircraft noise planning and regulations are being considered for a new environment, the en route environment. As policy makers search for bases for public policy in these new noise environments, it is appropriate to ask whether the same scientific evidence which supports airport noise policy can also support en route noise policy. Several aspects of that question are considered. An introduction establishes the scope of the present study and examines alternative study methodologies. Next, the selected study methodology is described and important assumptions are listed. The body of the paper then consists of the findings on en route issues. The final section presents findings on relevant research methods and considers priorities for further research.

  19. Road Traffic Noise Pollution Analysis for Cernavoda City

    Science.gov (United States)

    Manea, L.; Manea, A.; Florea, D.; Tarulescu, S.

    2017-10-01

    In the present paper was studied the noise pollution in Cernavodă city. The noise measurements were made for nine intersections from different city areas. Noise measurements were taken for three chosen routes with high population density, heavy traffic, commercial and residential buildings. Average, maximum and minimum values were collected and compared with standards. The impact of road traffic noise on the community depends on various factors such as road location and design, land use planning measures, building design, traffic composition, driver behaviour and the relief. In the study area 9 locations are identified to measure noise level. By using sound level meter noise levels are measured at different peak sessions i.e. morning, afternoon and evening. The presented values were collected for evening rush hour.

  20. A double-blind, randomized, comparative study of the use of a combination of uridine triphosphate trisodium, cytidine monophosphate disodium, and hydroxocobalamin, versus isolated treatment with hydroxocobalamin, in patients presenting with compressive neuralgias.

    Science.gov (United States)

    Goldberg, Henrique; Mibielli, Marco Antonio; Nunes, Carlos Pereira; Goldberg, Stephanie Wrobel; Buchman, Luiz; Mezitis, Spyros Ge; Rzetelna, Helio; Oliveira, Lisa; Geller, Mauro; Wajnsztajn, Fernanda

    2017-01-01

    This paper reports on the results of treatment of compressive neuralgia using a combination of nucleotides (uridine triphosphate trisodium [UTP] and cytidine monophosphate disodium [CMP]) and vitamin B12. To assess the safety and efficacy of the combination of nucleotides (UTP and CMP) and vitamin B12 in patients presenting with neuralgia arising from neural compression associated with degenerative orthopedic alterations and trauma, and to compare these effects with isolated administration of vitamin B12. A randomized, double-blind, controlled trial, consisting of a 30-day oral treatment period: Group A (n=200) receiving nucleotides + vitamin B12, and Group B (n=200) receiving vitamin B12 alone. The primary study endpoint was the percentage of subjects presenting pain visual analog scale (VAS) scores ≤20 at end of study treatment period. Secondary study endpoints included the percentage of subjects presenting improvement ≥5 points on the patient functionality questionnaire (PFQ); percentage of subjects presenting pain reduction (reduction in VAS scores at study end in relation to pretreatment); and number of subjects presenting adverse events. The results of this study showed a more expressive improvement in efficacy evaluations among subjects treated with the combination of nucleotides + vitamin B12, with a statistically significant superiority of the combination in pain reduction (evidenced by VAS scores). There were adverse events in both treatment groups, but these were transitory and no severe adverse event was recorded during the study period. Safety parameters were maintained throughout the study in both treatment groups. The combination of uridine, cytidine, and vitamin B12 was safe and effective in the treatment of neuralgias arising from neural compression associated with degenerative orthopedic alterations and trauma.