WorldWideScience

Sample records for random noise removal

  1. Random Valued Impulse Noise Removal Using Region Based Detection Approach

    Directory of Open Access Journals (Sweden)

    S. Banerjee

    2017-12-01

    Full Text Available Removal of random valued noisy pixel is extremely challenging when the noise density is above 50%. The existing filters are generally not capable of eliminating such noise when density is above 70%. In this paper a region wise density based detection algorithm for random valued impulse noise has been proposed. On the basis of the intensity values, the pixels of a particular window are sorted and then stored into four regions. The higher density based region is considered for stepwise detection of noisy pixels. As a result of this detection scheme a maximum of 75% of noisy pixels can be detected. For this purpose this paper proposes a unique noise removal algorithm. It was experimentally proved that the proposed algorithm not only performs exceptionally when it comes to visual qualitative judgment of standard images but also this filter combination outsmarts the existing algorithm in terms of MSE, PSNR and SSIM comparison even up to 70% noise density level.

  2. Removal of Stationary Sinusoidal Noise from Random Vibration Signals.

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Brian; Cap, Jerome S.

    2018-02-01

    In random vibration environments, sinusoidal line noise may appear in the vibration signal and can affect analysis of the resulting data. We studied two methods which remove stationary sine tones from random noise: a matrix inversion algorithm and a chirp-z transform algorithm. In addition, we developed new methods to determine the frequency of the tonal noise. The results show that both of the removal methods can eliminate sine tones in prefabricated random vibration data when the sine-to-random ratio is at least 0.25. For smaller ratios down to 0.02 only the matrix inversion technique can remove the tones, but the metrics to evaluate its effectiveness also degrade. We also found that using fast Fourier transforms best identified the tonal noise, and determined that band-pass-filtering the signals prior to the process improved sine removal. When applied to actual vibration test data, the methods were not as effective at removing harmonic tones, which we believe to be a result of mixed-phase sinusoidal noise.

  3. A Denoising Scheme for Randomly Clustered Noise Removal in ICCD Sensing Image

    Directory of Open Access Journals (Sweden)

    Fei Wang

    2017-01-01

    Full Text Available An Intensified Charge-Coupled Device (ICCD image is captured by the ICCD image sensor in extremely low-light conditions. Its noise has two distinctive characteristics. (a Different from the independent identically distributed (i.i.d. noise in natural image, the noise in the ICCD sensing image is spatially clustered, which induces unexpected structure information; (b The pattern of the clustered noise is formed randomly. In this paper, we propose a denoising scheme to remove the randomly clustered noise in the ICCD sensing image. First, we decompose the image into non-overlapped patches and classify them into flat patches and structure patches according to if real structure information is included. Then, two denoising algorithms are designed for them, respectively. For each flat patch, we simulate multiple similar patches for it in pseudo-time domain and remove its noise by averaging all the simulated patches, considering that the structure information induced by the noise varies randomly over time. For each structure patch, we design a structure-preserved sparse coding algorithm to reconstruct the real structure information. It reconstructs each patch by describing it as a weighted summation of its neighboring patches and incorporating the weights into the sparse representation of the current patch. Based on all the reconstructed patches, we generate a reconstructed image. After that, we repeat the whole process by changing relevant parameters, considering that blocking artifacts exist in a single reconstructed image. Finally, we obtain the reconstructed image by merging all the generated images into one. Experiments are conducted on an ICCD sensing image dataset, which verifies its subjective performance in removing the randomly clustered noise and preserving the real structure information in the ICCD sensing image.

  4. 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

  5. Restoration for Noise Removal in Quantum Images

    Science.gov (United States)

    Liu, Kai; Zhang, Yi; Lu, Kai; Wang, Xiaoping

    2017-09-01

    Quantum computation has become increasingly attractive in the past few decades due to its extraordinary performance. As a result, some studies focusing on image representation and processing via quantum mechanics have been done. However, few of them have considered the quantum operations for images restoration. To address this problem, three noise removal algorithms are proposed in this paper based on the novel enhanced quantum representation model, oriented to two kinds of noise pollution (Salt-and-Pepper noise and Gaussian noise). For the first algorithm Q-Mean, it is designed to remove the Salt-and-Pepper noise. The noise points are extracted through comparisons with the adjacent pixel values, after which the restoration operation is finished by mean filtering. As for the second method Q-Gauss, a special mask is applied to weaken the Gaussian noise pollution. The third algorithm Q-Adapt is effective for the source image containing unknown noise. The type of noise can be judged through the quantum statistic operations for the color value of the whole image, and then different noise removal algorithms are used to conduct image restoration respectively. Performance analysis reveals that our methods can offer high restoration quality and achieve significant speedup through inherent parallelism of quantum computation.

  6. Quantum-noise randomized ciphers

    International Nuclear Information System (INIS)

    Nair, Ranjith; Yuen, Horace P.; Kumar, Prem; Corndorf, Eric; Eguchi, Takami

    2006-01-01

    We review the notion of a classical random cipher and its advantages. We sharpen the usual description of random ciphers to a particular mathematical characterization suggested by the salient feature responsible for their increased security. We describe a concrete system known as αη and show that it is equivalent to a random cipher in which the required randomization is affected by coherent-state quantum noise. We describe the currently known security features of αη and similar systems, including lower bounds on the unicity distances against ciphertext-only and known-plaintext attacks. We show how αη used in conjunction with any standard stream cipher such as the Advanced Encryption Standard provides an additional, qualitatively different layer of security from physical encryption against known-plaintext attacks on the key. We refute some claims in the literature that αη is equivalent to a nonrandom stream cipher

  7. Is fMRI "noise" really noise? Resting state nuisance regressors remove variance with network structure.

    Science.gov (United States)

    Bright, Molly G; Murphy, Kevin

    2015-07-01

    Noise correction is a critical step towards accurate mapping of resting state BOLD fMRI connectivity. Noise sources related to head motion or physiology are typically modelled by nuisance regressors, and a generalised linear model is applied to regress out the associated signal variance. In this study, we use independent component analysis (ICA) to characterise the data variance typically discarded in this pre-processing stage in a cohort of 12 healthy volunteers. The signal variance removed by 24, 12, 6, or only 3 head motion parameters demonstrated network structure typically associated with functional connectivity, and certain networks were discernable in the variance extracted by as few as 2 physiologic regressors. Simulated nuisance regressors, unrelated to the true data noise, also removed variance with network structure, indicating that any group of regressors that randomly sample variance may remove highly structured "signal" as well as "noise." Furthermore, to support this we demonstrate that random sampling of the original data variance continues to exhibit robust network structure, even when as few as 10% of the original volumes are considered. Finally, we examine the diminishing returns of increasing the number of nuisance regressors used in pre-processing, showing that excessive use of motion regressors may do little better than chance in removing variance within a functional network. It remains an open challenge to understand the balance between the benefits and confounds of noise correction using nuisance regressors. Copyright © 2015. Published by Elsevier Inc.

  8. Image processing on the image with pixel noise bits removed

    Science.gov (United States)

    Chuang, Keh-Shih; Wu, Christine

    1992-06-01

    Our previous studies used statistical methods to assess the noise level in digital images of various radiological modalities. We separated the pixel data into signal bits and noise bits and demonstrated visually that the removal of the noise bits does not affect the image quality. In this paper we apply image enhancement techniques on noise-bits-removed images and demonstrate that the removal of noise bits has no effect on the image property. The image processing techniques used are gray-level look up table transformation, Sobel edge detector, and 3-D surface display. Preliminary results show no noticeable difference between original image and noise bits removed image using look up table operation and Sobel edge enhancement. There is a slight enhancement of the slicing artifact in the 3-D surface display of the noise bits removed image.

  9. Random Correlation Matrix and De-Noising

    OpenAIRE

    Ken-ichi Mitsui; Yoshio Tabata

    2006-01-01

    In Finance, the modeling of a correlation matrix is one of the important problems. In particular, the correlation matrix obtained from market data has the noise. Here we apply the de-noising processing based on the wavelet analysis to the noisy correlation matrix, which is generated by a parametric function with random parameters. First of all, we show that two properties, i.e. symmetry and ones of all diagonal elements, of the correlation matrix preserve via the de-noising processing and the...

  10. Impulsive noise removal from color video with morphological filtering

    Science.gov (United States)

    Ruchay, Alexey; Kober, Vitaly

    2017-09-01

    This paper deals with impulse noise removal from color video. The proposed noise removal algorithm employs a switching filtering for denoising of color video; that is, detection of corrupted pixels by means of a novel morphological filtering followed by removal of the detected pixels on the base of estimation of uncorrupted pixels in the previous scenes. With the help of computer simulation we show that the proposed algorithm is able to well remove impulse noise in color video. The performance of the proposed algorithm is compared in terms of image restoration metrics with that of common successful algorithms.

  11. Applications of digital processing for noise removal from plasma diagnostics

    International Nuclear Information System (INIS)

    Kane, R.J.; Candy, J.V.; Casper, T.A.

    1985-01-01

    The use of digital signal techniques for removal of noise components present in plasma diagnostic signals is discussed, particularly with reference to diamagnetic loop signals. These signals contain noise due to power supply ripple in addition to plasma characteristics. The application of noise canceling techniques, such as adaptive noise canceling and model-based estimation, will be discussed. The use of computer codes such as SIG is described. 19 refs., 5 figs

  12. Noise removal in multichannel image data by a parametric maximum noise fraction estimator

    DEFF Research Database (Denmark)

    Conradsen, Knut; Ersbøll, Bjarne Kjær; Nielsen, Allan Aasbjerg

    1991-01-01

    Some approaches to noise removal in multispectral imagery are presented. The primary contribution of the present work is the establishment of several ways of estimating the noise covariance matrix from image data and a comparison of the noise separation performances. A case study with Landsat MSS...

  13. Analysis and removing noise from speech using wavelet transform

    Science.gov (United States)

    Tomala, Karel; Voznak, Miroslav; Partila, Pavol; Rezac, Filip; Safarik, Jakub

    2013-05-01

    The paper discusses the use of Discrete Wavelet Transform (DWT) and Stationary Wavelet Transform (SWT) wavelet in removing noise from voice samples and evaluation of its impact on speech quality. One significant part of Quality of Service (QoS) in communication technology is the speech quality assessment. However, this part is seriously overlooked as telecommunication providers often focus on increasing network capacity, expansion of services offered and their enforcement in the market. Among the fundamental factors affecting the transmission properties of the communication chain is noise, either at the transmitter or the receiver side. A wavelet transform (WT) is a modern tool for signal processing. One of the most significant areas in which wavelet transforms are used is applications designed to suppress noise in signals. To remove noise from the voice sample in our experiment, we used the reference segment of the voice which was distorted by Gaussian white noise. An evaluation of the impact on speech quality was carried out by an intrusive objective algorithm Perceptual Evaluation of Speech Quality (PESQ). DWT and SWT transformation was applied to voice samples that were devalued by Gaussian white noise. Afterwards, we determined the effectiveness of DWT and SWT by means of objective algorithm PESQ. The decisive criterion for determining the quality of a voice sample once the noise had been removed was Mean Opinion Score (MOS) which we obtained in PESQ. The contribution of this work lies in the evaluation of efficiency of wavelet transformation to suppress noise in voice samples.

  14. Noise removing in encrypted color images by statistical analysis

    Science.gov (United States)

    Islam, N.; Puech, W.

    2012-03-01

    Cryptographic techniques are used to secure confidential data from unauthorized access but these techniques are very sensitive to noise. A single bit change in encrypted data can have catastrophic impact over the decrypted data. This paper addresses the problem of removing bit error in visual data which are encrypted using AES algorithm in the CBC mode. In order to remove the noise, a method is proposed which is based on the statistical analysis of each block during the decryption. The proposed method exploits local statistics of the visual data and confusion/diffusion properties of the encryption algorithm to remove the errors. Experimental results show that the proposed method can be used at the receiving end for the possible solution for noise removing in visual data in encrypted domain.

  15. Removing the subjectivity from tonal noise assessment

    International Nuclear Information System (INIS)

    Ruffle, R.; Bass, J.; Bullmore, A.

    1995-01-01

    The aim of this work is to identify an objective measure of tones in wind farm noise that corresponds to perception both within and outside of the wind energy industry. The Joint Nordic Method (currently the most widely used assessment in Europe) has been analysed with regard to variability and correlation to subjective results. It has been found that there is considerable scope in the Joint Nordic Method for obtaining different results, for the same wind farm. This is because the method is not clearly specified in all areas. Therefore, a new more tightly defined method, based on the Joint Nordic Method were possible, is outlined here. Initial analysis indicates that the new measure is appropriate and further validation is ongoing. (Author)

  16. An approach to remove impulse noise from a corrupted image

    International Nuclear Information System (INIS)

    Jin, Cong; Yan, Meng; Jin, Shu-Wei

    2013-01-01

    In this paper, we propose an efficient approach for detecting the impulse noise from corrupted images. This method is based on the principle that the feature of the digital image is usually local correlation and the feature of the impulse noise is usually located near one of the two ends of the image’s maximum and minimum gray values. After the noisy pixel has been detected by the proposed detector, a modified version of the mean filter is proposed to remove the detected impulse noise. Experimental results show that the implementation of the proposed method is simple, and it has better performance than comparison filters with regard to effective noise suppression and preservation of detail, especially when the noise ratio is very high. (paper)

  17. The importance for speech intelligibility of random fluctuations in "steady" background noise.

    Science.gov (United States)

    Stone, Michael A; Füllgrabe, Christian; Mackinnon, Robert C; Moore, Brian C J

    2011-11-01

    Spectrally shaped steady noise is commonly used as a masker of speech. The effects of inherent random fluctuations in amplitude of such a noise are typically ignored. Here, the importance of these random fluctuations was assessed by comparing two cases. For one, speech was mixed with steady speech-shaped noise and N-channel tone vocoded, a process referred to as signal-domain mixing (SDM); this preserved the random fluctuations of the noise. For the second, the envelope of speech alone was extracted for each vocoder channel and a constant was added corresponding to the root-mean-square value of the noise envelope for that channel. This is referred to as envelope-domain mixing (EDM); it removed the random fluctuations of the noise. Sinusoidally modulated noise and a single talker were also used as backgrounds, with both SDM and EDM. Speech intelligibility was measured for N = 12, 19, and 30, with the target-to-background ratio fixed at -7 dB. For SDM, performance was best for the speech background and worst for the steady noise. For EDM, this pattern was reversed. Intelligibility with steady noise was consistently very poor for SDM, but near-ceiling for EDM, demonstrating that the random fluctuations in steady noise have a large effect.

  18. Is fMRI ?noise? really noise? Resting state nuisance regressors remove variance with network structure

    OpenAIRE

    Bright, Molly G.; Murphy, Kevin

    2015-01-01

    Noise correction is a critical step towards accurate mapping of resting state BOLD fMRI connectivity. Noise sources related to head motion or physiology are typically modelled by nuisance regressors, and a generalised linear model is applied to regress out the associated signal variance. In this study, we use independent component analysis (ICA) to characterise the data variance typically discarded in this pre-processing stage in a cohort of 12 healthy volunteers. The signal variance removed ...

  19. Empirical mode decomposition of the ECG signal for noise removal

    Science.gov (United States)

    Khan, Jesmin; Bhuiyan, Sharif; Murphy, Gregory; Alam, Mohammad

    2011-04-01

    Electrocardiography is a diagnostic procedure for the detection and diagnosis of heart abnormalities. The electrocardiogram (ECG) signal contains important information that is utilized by physicians for the diagnosis and analysis of heart diseases. So good quality ECG signal plays a vital role for the interpretation and identification of pathological, anatomical and physiological aspects of the whole cardiac muscle. However, the ECG signals are corrupted by noise which severely limit the utility of the recorded ECG signal for medical evaluation. The most common noise presents in the ECG signal is the high frequency noise caused by the forces acting on the electrodes. In this paper, we propose a new ECG denoising method based on the empirical mode decomposition (EMD). The proposed method is able to enhance the ECG signal upon removing the noise with minimum signal distortion. Simulation is done on the MIT-BIH database to verify the efficacy of the proposed algorithm. Experiments show that the presented method offers very good results to remove noise from the ECG signal.

  20. Comparison of methods for removing electromagnetic noise from electromyographic signals.

    Science.gov (United States)

    Defreitas, Jason M; Beck, Travis W; Stock, Matt S

    2012-02-01

    The purpose of this investigation was to compare three different methods of removing noise from monopolar electromyographic (EMG) signals: (a) electrical shielding with a Faraday cage, (b) denoising with a digital notch-filter and (c) applying a bipolar differentiation with another monopolar EMG signal. Ten men and ten women (mean age = 24.0 years) performed isometric muscle actions of the leg extensors at 10-100% of their maximal voluntary contraction on two separate occasions. One trial was performed inside a Faraday tent (a flexible Faraday cage made from conductive material), and the other was performed outside the Faraday tent. The EMG signals collected outside the Faraday tent were analyzed three separate ways: as a raw signal, as a bipolar signal, and as a signal digitally notch filtered to remove 60 Hz noise and its harmonics. The signal-to-noise ratios were greatest after notch-filtering (range: 3.0-33.8), and lowest for the bipolar arrangement (1.6-10.2). Linear slope coefficients for the EMG amplitude versus force relationship were also used to compare the methods of noise removal. The results showed that a bipolar arrangement had a significantly lower linear slope coefficient when compared to the three other conditions (raw, notch and tent). These results suggested that an appropriately filtered monopolar EMG signal can be useful in situations that require a large pick-up area. Furthermore, although it is helpful, a Faraday tent (or cage) is not required to achieve an appropriate signal-to-noise ratio, as long as the correct filters are applied.

  1. Comparison of methods for removing electromagnetic noise from electromyographic signals

    International Nuclear Information System (INIS)

    DeFreitas, Jason M; Beck, Travis W; Stock, Matt S

    2012-01-01

    The purpose of this investigation was to compare three different methods of removing noise from monopolar electromyographic (EMG) signals: (a) electrical shielding with a Faraday cage, (b) denoising with a digital notch-filter and (c) applying a bipolar differentiation with another monopolar EMG signal. Ten men and ten women (mean age = 24.0 years) performed isometric muscle actions of the leg extensors at 10–100% of their maximal voluntary contraction on two separate occasions. One trial was performed inside a Faraday tent (a flexible Faraday cage made from conductive material), and the other was performed outside the Faraday tent. The EMG signals collected outside the Faraday tent were analyzed three separate ways: as a raw signal, as a bipolar signal, and as a signal digitally notch filtered to remove 60 Hz noise and its harmonics. The signal-to-noise ratios were greatest after notch-filtering (range: 3.0–33.8), and lowest for the bipolar arrangement (1.6–10.2). Linear slope coefficients for the EMG amplitude versus force relationship were also used to compare the methods of noise removal. The results showed that a bipolar arrangement had a significantly lower linear slope coefficient when compared to the three other conditions (raw, notch and tent). These results suggested that an appropriately filtered monopolar EMG signal can be useful in situations that require a large pick-up area. Furthermore, although it is helpful, a Faraday tent (or cage) is not required to achieve an appropriate signal-to-noise ratio, as long as the correct filters are applied. (paper)

  2. Time-frequency peak filtering for random noise attenuation of magnetic resonance sounding signal

    Science.gov (United States)

    Lin, Tingting; Zhang, Yang; Yi, Xiaofeng; Fan, Tiehu; Wan, Ling

    2018-05-01

    When measuring in a geomagnetic field, the method of magnetic resonance sounding (MRS) is often limited because of the notably low signal-to-noise ratio (SNR). Most current studies focus on discarding spiky noise and power-line harmonic noise cancellation. However, the effects of random noise should not be underestimated. The common method for random noise attenuation is stacking, but collecting multiple recordings merely to suppress random noise is time-consuming. Moreover, stacking is insufficient to suppress high-level random noise. Here, we propose the use of time-frequency peak filtering for random noise attenuation, which is performed after the traditional de-spiking and power-line harmonic removal method. By encoding the noisy signal with frequency modulation and estimating the instantaneous frequency using the peak of the time-frequency representation of the encoded signal, the desired MRS signal can be acquired from only one stack. The performance of the proposed method is tested on synthetic envelope signals and field data from different surveys. Good estimations of the signal parameters are obtained at different SNRs. Moreover, an attempt to use the proposed method to handle a single recording provides better results compared to 16 stacks. Our results suggest that the number of stacks can be appropriately reduced to shorten the measurement time and improve the measurement efficiency.

  3. Decision-Based Marginal Total Variation Diffusion for Impulsive Noise Removal in Color Images

    Directory of Open Access Journals (Sweden)

    Hongyao Deng

    2017-01-01

    Full Text Available Impulsive noise removal for color images usually employs vector median filter, switching median filter, the total variation L1 method, and variants. These approaches, however, often introduce excessive smoothing and can result in extensive visual feature blurring and thus are suitable only for images with low density noise. A marginal method to reduce impulsive noise is proposed in this paper that overcomes this limitation that is based on the following facts: (i each channel in a color image is contaminated independently, and contaminative components are independent and identically distributed; (ii in a natural image the gradients of different components of a pixel are similar to one another. This method divides components into different categories based on different noise characteristics. If an image is corrupted by salt-and-pepper noise, the components are divided into the corrupted and the noise-free components; if the image is corrupted by random-valued impulses, the components are divided into the corrupted, noise-free, and the possibly corrupted components. Components falling into different categories are processed differently. If a component is corrupted, modified total variation diffusion is applied; if it is possibly corrupted, scaled total variation diffusion is applied; otherwise, the component is left unchanged. Simulation results demonstrate its effectiveness.

  4. Optimal source coding, removable noise elimination, and natural coordinate system construction for general vector sources using replicator neural networks

    Science.gov (United States)

    Hecht-Nielsen, Robert

    1997-04-01

    A new universal one-chart smooth manifold model for vector information sources is introduced. Natural coordinates (a particular type of chart) for such data manifolds are then defined. Uniformly quantized natural coordinates form an optimal vector quantization code for a general vector source. Replicator neural networks (a specialized type of multilayer perceptron with three hidden layers) are the introduced. As properly configured examples of replicator networks approach minimum mean squared error (e.g., via training and architecture adjustment using randomly chosen vectors from the source), these networks automatically develop a mapping which, in the limit, produces natural coordinates for arbitrary source vectors. The new concept of removable noise (a noise model applicable to a wide variety of real-world noise processes) is then discussed. Replicator neural networks, when configured to approach minimum mean squared reconstruction error (e.g., via training and architecture adjustment on randomly chosen examples from a vector source, each with randomly chosen additive removable noise contamination), in the limit eliminate removable noise and produce natural coordinates for the data vector portions of the noise-corrupted source vectors. Consideration regarding selection of the dimension of a data manifold source model and the training/configuration of replicator neural networks are discussed.

  5. Removal of impulse noise clusters from color images with local order statistics

    Science.gov (United States)

    Ruchay, Alexey; Kober, Vitaly

    2017-09-01

    This paper proposes a novel algorithm for restoring images corrupted with clusters of impulse noise. The noise clusters often occur when the probability of impulse noise is very high. The proposed noise removal algorithm consists of detection of bulky impulse noise in three color channels with local order statistics followed by removal of the detected clusters by means of vector median filtering. With the help of computer simulation we show that the proposed algorithm is able to effectively remove clustered impulse noise. The performance of the proposed algorithm is compared in terms of image restoration metrics with that of common successful algorithms.

  6. The clustering of local maxima in random noise

    International Nuclear Information System (INIS)

    Coles, P.

    1989-01-01

    A mixture of analytic and numerical techniques is used to study the clustering properties of local maxima of random noise. Technical complexities restrict us to the case of 1D noise, but the results obtained should give a reasonably accurate picture of the behaviour of cosmological density peaks in noise defined on a 3D domain. We give estimates of the two-point correlation function of local maxima, for both Gaussian and non-Gaussian noise and show that previous approximations are not accurate. (author)

  7. 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.

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

    International Nuclear Information System (INIS)

    Xu Yong; Gu Rencai; Zhang Huiqing

    2011-01-01

    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.

  9. Is fMRI “noise” really noise? Resting state nuisance regressors remove variance with network structure

    Science.gov (United States)

    Bright, Molly G.; Murphy, Kevin

    2015-01-01

    Noise correction is a critical step towards accurate mapping of resting state BOLD fMRI connectivity. Noise sources related to head motion or physiology are typically modelled by nuisance regressors, and a generalised linear model is applied to regress out the associated signal variance. In this study, we use independent component analysis (ICA) to characterise the data variance typically discarded in this pre-processing stage in a cohort of 12 healthy volunteers. The signal variance removed by 24, 12, 6, or only 3 head motion parameters demonstrated network structure typically associated with functional connectivity, and certain networks were discernable in the variance extracted by as few as 2 physiologic regressors. Simulated nuisance regressors, unrelated to the true data noise, also removed variance with network structure, indicating that any group of regressors that randomly sample variance may remove highly structured “signal” as well as “noise.” Furthermore, to support this we demonstrate that random sampling of the original data variance continues to exhibit robust network structure, even when as few as 10% of the original volumes are considered. Finally, we examine the diminishing returns of increasing the number of nuisance regressors used in pre-processing, showing that excessive use of motion regressors may do little better than chance in removing variance within a functional network. It remains an open challenge to understand the balance between the benefits and confounds of noise correction using nuisance regressors. PMID:25862264

  10. The deterministic chaos and random noise in turbulent jet

    International Nuclear Information System (INIS)

    Yao, Tian-Liang; Liu, Hai-Feng; Xu, Jian-Liang; Li, Wei-Feng

    2014-01-01

    A turbulent flow is usually treated as a superposition of coherent structure and incoherent turbulence. In this paper, the largest Lyapunov exponent and the random noise in the near field of round jet and plane jet are estimated with our previously proposed method of chaotic time series analysis [T. L. Yao, et al., Chaos 22, 033102 (2012)]. The results show that the largest Lyapunov exponents of the round jet and plane jet are in direct proportion to the reciprocal of the integral time scale of turbulence, which is in accordance with the results of the dimensional analysis, and the proportionality coefficients are equal. In addition, the random noise of the round jet and plane jet has the same linear relation with the Kolmogorov velocity scale of turbulence. As a result, the random noise may well be from the incoherent disturbance in turbulence, and the coherent structure in turbulence may well follow the rule of chaotic motion

  11. Fuzzy Logic-Based Filter for Removing Additive and Impulsive Noise from Color Images

    Science.gov (United States)

    Zhu, Yuhong; Li, Hongyang; Jiang, Huageng

    2017-12-01

    This paper presents an efficient filter method based on fuzzy logics for adaptively removing additive and impulsive noise from color images. The proposed filter comprises two parts including noise detection and noise removal filtering. In the detection part, the fuzzy peer group concept is applied to determine what type of noise is added to each pixel of the corrupted image. In the filter part, the impulse noise is deducted by the vector median filter in the CIELAB color space and an optimal fuzzy filter is introduced to reduce the Gaussian noise, while they can work together to remove the mixed Gaussian-impulse noise from color images. Experimental results on several color images proves the efficacy of the proposed fuzzy filter.

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

    African Journals Online (AJOL)

    The process of the survival of species dependent on a limited resource in a polluted environment which isnot a new idea can be described by the technique of a mathematical modelling. We have utilised the technique of a numerical simulation to study the impact of environmental random noise on the carrying capacities of ...

  13. 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

  14. GPR random noise reduction using BPD and EMD

    Science.gov (United States)

    Ostoori, Roya; Goudarzi, Alireza; Oskooi, Behrooz

    2018-04-01

    Ground-penetrating radar (GPR) exploration is a new high-frequency technology that explores near-surface objects and structures accurately. The high-frequency antenna of the GPR system makes it a high-resolution method compared to other geophysical methods. The frequency range of recorded GPR is so wide that random noise recording is inevitable due to acquisition. This kind of noise comes from unknown sources and its correlation to the adjacent traces is nearly zero. This characteristic of random noise along with the higher accuracy of GPR system makes denoising very important for interpretable results. The main objective of this paper is to reduce GPR random noise based on pursuing denoising using empirical mode decomposition. Our results showed that empirical mode decomposition in combination with basis pursuit denoising (BPD) provides satisfactory outputs due to the sifting process compared to the time-domain implementation of the BPD method on both synthetic and real examples. Our results demonstrate that because of the high computational costs, the BPD-empirical mode decomposition technique should only be used for heavily noisy signals.

  15. Partial removal of correlated noise in thermal imagery

    International Nuclear Information System (INIS)

    Borel, C.C.; Cooke, B.J.; Laubscher, B.E.

    1996-01-01

    Correlated noise occurs in many imaging systems such as scanners and push-broom imagers. The sources of correlated noise can be from the detectors, pre-amplifiers and sampling circuits. Correlated noise appears as streaking along the scan direction of a scanner or in the along track direction of a push-broom imager. We have developed algorithms to simulate correlated noise and pre-filter to reduce the amount of streaking while not destroying the scene content. The pre- filter in the Fourier domain consists of the product of two filters. One filter models the correlated noise spectrum, the other is a windowing function e.g. Gaussian or Hanning window with variable width to block high frequency noise away from the origin of the Fourier Transform of the image data. We have optimized the filter parameters for various scenes and find improvements of the RMS error of the original minus the pre-filtered noisy image

  16. 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.

  17. Random walk in dynamically disordered chains: Poisson white noise disorder

    International Nuclear Information System (INIS)

    Hernandez-Garcia, E.; Pesquera, L.; Rodriguez, M.A.; San Miguel, M.

    1989-01-01

    Exact solutions are given for a variety of models of random walks in a chain with time-dependent disorder. Dynamic disorder is modeled by white Poisson noise. Models with site-independent (global) and site-dependent (local) disorder are considered. Results are described in terms of an affective random walk in a nondisordered medium. In the cases of global disorder the effective random walk contains multistep transitions, so that the continuous limit is not a diffusion process. In the cases of local disorder the effective process is equivalent to usual random walk in the absence of disorder but with slower diffusion. Difficulties associated with the continuous-limit representation of random walk in a disordered chain are discussed. In particular, the authors consider explicit cases in which taking the continuous limit and averaging over disorder sources do not commute

  18. Directional Total Generalized Variation Regularization for Impulse Noise Removal

    DEFF Research Database (Denmark)

    Kongskov, Rasmus Dalgas; Dong, Yiqiu

    2017-01-01

    this regularizer for directional images is highly advantageous. In order to estimate directions in impulse noise corrupted images, which is much more challenging compared to Gaussian noise corrupted images, we introduce a new Fourier transform-based method. Numerical experiments show that this method is more...

  19. Listening to the Noise: Random Fluctuations Reveal Gene Network Parameters

    Science.gov (United States)

    Munsky, Brian; Trinh, Brooke; Khammash, Mustafa

    2010-03-01

    The cellular environment is abuzz with noise originating from the inherent random motion of reacting molecules in the living cell. In this noisy environment, clonal cell populations exhibit cell-to-cell variability that can manifest significant prototypical differences. Noise induced stochastic fluctuations in cellular constituents can be measured and their statistics quantified using flow cytometry, single molecule fluorescence in situ hybridization, time lapse fluorescence microscopy and other single cell and single molecule measurement techniques. 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. We use theoretical investigations to establish experimental guidelines for the identification of gene regulatory networks, and we apply these guideline to experimentally identify predictive models for different regulatory mechanisms in bacteria and yeast.

  20. Removing Background Noise with Phased Array Signal Processing

    Science.gov (United States)

    Podboy, Gary; Stephens, David

    2015-01-01

    Preliminary results are presented from a test conducted to determine how well microphone phased array processing software could pull an acoustic signal out of background noise. The array consisted of 24 microphones in an aerodynamic fairing designed to be mounted in-flow. The processing was conducted using Functional Beam forming software developed by Optinav combined with cross spectral matrix subtraction. The test was conducted in the free-jet of the Nozzle Acoustic Test Rig at NASA GRC. The background noise was produced by the interaction of the free-jet flow with the solid surfaces in the flow. The acoustic signals were produced by acoustic drivers. The results show that the phased array processing was able to pull the acoustic signal out of the background noise provided the signal was no more than 20 dB below the background noise level measured using a conventional single microphone equipped with an aerodynamic forebody.

  1. Intelligent Noise Removal from EMG Signal Using Focused Time-Lagged Recurrent Neural Network

    Directory of Open Access Journals (Sweden)

    S. N. Kale

    2009-01-01

    Full Text Available Electromyography (EMG signals can be used for clinical/biomedical application and modern human computer interaction. EMG signals acquire noise while traveling through tissue, inherent noise in electronics equipment, ambient noise, and so forth. ANN approach is studied for reduction of noise in EMG signal. In this paper, it is shown that Focused Time-Lagged Recurrent Neural Network (FTLRNN can elegantly solve to reduce the noise from EMG signal. After rigorous computer simulations, authors developed an optimal FTLRNN model, which removes the noise from the EMG signal. Results show that the proposed optimal FTLRNN model has an MSE (Mean Square Error as low as 0.000067 and 0.000048, correlation coefficient as high as 0.99950 and 0.99939 for noise signal and EMG signal, respectively, when validated on the test dataset. It is also noticed that the output of the estimated FTLRNN model closely follows the real one. This network is indeed robust as EMG signal tolerates the noise variance from 0.1 to 0.4 for uniform noise and 0.30 for Gaussian noise. It is clear that the training of the network is independent of specific partitioning of dataset. It is seen that the performance of the proposed FTLRNN model clearly outperforms the best Multilayer perceptron (MLP and Radial Basis Function NN (RBF models. The simple NN model such as the FTLRNN with single-hidden layer can be employed to remove noise from EMG signal.

  2. Impulse noise estimation and removal for OFDM systems

    KAUST Repository

    Al-Naffouri, Tareq Y.

    2014-03-01

    Orthogonal Frequency Division Multiplexing (OFDM) is a modulation scheme that is widely used in wired and wireless communication systems. While OFDM is ideally suited to deal with frequency selective channels and AWGN, its performance may be dramatically impacted by the presence of impulse noise. In fact, very strong noise impulses in the time domain might result in the erasure of whole OFDM blocks of symbols at the receiver. Impulse noise can be mitigated by considering it as a sparse signal in time, and using recently developed algorithms for sparse signal reconstruction. We propose an algorithm that utilizes the guard band subcarriers for the impulse noise estimation and cancellation. Instead of relying on ℓ1 minimization as done in some popular general-purpose compressive sensing schemes, the proposed method jointly exploits the specific structure of this problem and the available a priori information for sparse signal recovery. The computational complexity of the proposed algorithm is very competitive with respect to sparse signal reconstruction schemes based on ℓ1 minimization. The proposed method is compared with respect to other state-of-the-art methods in terms of achievable rates for an OFDM system with impulse noise and AWGN. © 2014 IEEE.

  3. Impulse noise estimation and removal for OFDM systems

    KAUST Repository

    Al-Naffouri, Tareq Y.; Quadeer, Ahmed Abdul; Caire, Giuseppe

    2014-01-01

    Orthogonal Frequency Division Multiplexing (OFDM) is a modulation scheme that is widely used in wired and wireless communication systems. While OFDM is ideally suited to deal with frequency selective channels and AWGN, its performance may be dramatically impacted by the presence of impulse noise. In fact, very strong noise impulses in the time domain might result in the erasure of whole OFDM blocks of symbols at the receiver. Impulse noise can be mitigated by considering it as a sparse signal in time, and using recently developed algorithms for sparse signal reconstruction. We propose an algorithm that utilizes the guard band subcarriers for the impulse noise estimation and cancellation. Instead of relying on ℓ1 minimization as done in some popular general-purpose compressive sensing schemes, the proposed method jointly exploits the specific structure of this problem and the available a priori information for sparse signal recovery. The computational complexity of the proposed algorithm is very competitive with respect to sparse signal reconstruction schemes based on ℓ1 minimization. The proposed method is compared with respect to other state-of-the-art methods in terms of achievable rates for an OFDM system with impulse noise and AWGN. © 2014 IEEE.

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

    International Nuclear Information System (INIS)

    Kong, Dehui; Peng, Zhenming

    2015-01-01

    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. (paper)

  5. 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.

  6. Wavelet tree structure based speckle noise removal for optical coherence tomography

    Science.gov (United States)

    Yuan, Xin; Liu, Xuan; Liu, Yang

    2018-02-01

    We report a new speckle noise removal algorithm in optical coherence tomography (OCT). Though wavelet domain thresholding algorithms have demonstrated superior advantages in suppressing noise magnitude and preserving image sharpness in OCT, the wavelet tree structure has not been investigated in previous applications. In this work, we propose an adaptive wavelet thresholding algorithm via exploiting the tree structure in wavelet coefficients to remove the speckle noise in OCT images. The threshold for each wavelet band is adaptively selected following a special rule to retain the structure of the image across different wavelet layers. Our results demonstrate that the proposed algorithm outperforms conventional wavelet thresholding, with significant advantages in preserving image features.

  7. Background Noise Removal in Ultrasonic B-scan Images Using Iterative Statistical Techniques

    NARCIS (Netherlands)

    Wells, I.; Charlton, P. C.; Mosey, S.; Donne, K. E.

    2008-01-01

    The interpretation of ultrasonic B-scan images can be a time-consuming process and its success depends on operator skills and experience. Removal of the image background will potentially improve its quality and hence improve operator diagnosis. An automatic background noise removal algorithm is

  8. Poisson noise removal with pyramidal multi-scale transforms

    Science.gov (United States)

    Woiselle, Arnaud; Starck, Jean-Luc; Fadili, Jalal M.

    2013-09-01

    In this paper, we introduce a method to stabilize the variance of decimated transforms using one or two variance stabilizing transforms (VST). These VSTs are applied to the 3-D Meyer wavelet pyramidal transform which is the core of the first generation 3D curvelets. This allows us to extend these 3-D curvelets to handle Poisson noise, that we apply to the denoising of a simulated cosmological volume.

  9. CLEANing the Reward: Counterfactual Actions to Remove Exploratory Action Noise in Multiagent Learning

    Science.gov (United States)

    HolmesParker, Chris; Taylor, Mathew E.; Tumer, Kagan; Agogino, Adrian

    2014-01-01

    Learning in multiagent systems can be slow because agents must learn both how to behave in a complex environment and how to account for the actions of other agents. The inability of an agent to distinguish between the true environmental dynamics and those caused by the stochastic exploratory actions of other agents creates noise in each agent's reward signal. This learning noise can have unforeseen and often undesirable effects on the resultant system performance. We define such noise as exploratory action noise, demonstrate the critical impact it can have on the learning process in multiagent settings, and introduce a reward structure to effectively remove such noise from each agent's reward signal. In particular, we introduce Coordinated Learning without Exploratory Action Noise (CLEAN) rewards and empirically demonstrate their benefits

  10. Salt-and-pepper noise removal using modified mean filter and total variation minimization

    Science.gov (United States)

    Aghajarian, Mickael; McInroy, John E.; Wright, Cameron H. G.

    2018-01-01

    The search for effective noise removal algorithms is still a real challenge in the field of image processing. An efficient image denoising method is proposed for images that are corrupted by salt-and-pepper noise. Salt-and-pepper noise takes either the minimum or maximum intensity, so the proposed method restores the image by processing the pixels whose values are either 0 or 255 (assuming an 8-bit/pixel image). For low levels of noise corruption (less than or equal to 50% noise density), the method employs the modified mean filter (MMF), while for heavy noise corruption, noisy pixels values are replaced by the weighted average of the MMF and the total variation of corrupted pixels, which is minimized using convex optimization. Two fuzzy systems are used to determine the weights for taking average. To evaluate the performance of the algorithm, several test images with different noise levels are restored, and the results are quantitatively measured by peak signal-to-noise ratio and mean absolute error. The results show that the proposed scheme gives considerable noise suppression up to a noise density of 90%, while almost completely maintaining edges and fine details of the original image.

  11. A Shearlet-based algorithm for quantum noise removal in low-dose CT images

    Science.gov (United States)

    Zhang, Aguan; Jiang, Huiqin; Ma, Ling; Liu, Yumin; Yang, Xiaopeng

    2016-03-01

    Low-dose CT (LDCT) scanning is a potential way to reduce the radiation exposure of X-ray in the population. It is necessary to improve the quality of low-dose CT images. In this paper, we propose an effective algorithm for quantum noise removal in LDCT images using shearlet transform. Because the quantum noise can be simulated by Poisson process, we first transform the quantum noise by using anscombe variance stabilizing transform (VST), producing an approximately Gaussian noise with unitary variance. Second, the non-noise shearlet coefficients are obtained by adaptive hard-threshold processing in shearlet domain. Third, we reconstruct the de-noised image using the inverse shearlet transform. Finally, an anscombe inverse transform is applied to the de-noised image, which can produce the improved image. The main contribution is to combine the anscombe VST with the shearlet transform. By this way, edge coefficients and noise coefficients can be separated from high frequency sub-bands effectively. A number of experiments are performed over some LDCT images by using the proposed method. Both quantitative and visual results show that the proposed method can effectively reduce the quantum noise while enhancing the subtle details. It has certain value in clinical application.

  12. Wavelets, ridgelets, and curvelets for Poisson noise removal.

    Science.gov (United States)

    Zhang, Bo; Fadili, Jalal M; Starck, Jean-Luc

    2008-07-01

    In order to denoise Poisson count data, we introduce a variance stabilizing transform (VST) applied on a filtered discrete Poisson process, yielding a near Gaussian process with asymptotic constant variance. This new transform, which can be deemed as an extension of the Anscombe transform to filtered data, is simple, fast, and efficient in (very) low-count situations. We combine this VST with the filter banks of wavelets, ridgelets and curvelets, leading to multiscale VSTs (MS-VSTs) and nonlinear decomposition schemes. By doing so, the noise-contaminated coefficients of these MS-VST-modified transforms are asymptotically normally distributed with known variances. A classical hypothesis-testing framework is adopted to detect the significant coefficients, and a sparsity-driven iterative scheme reconstructs properly the final estimate. A range of examples show the power of this MS-VST approach for recovering important structures of various morphologies in (very) low-count images. These results also demonstrate that the MS-VST approach is competitive relative to many existing denoising methods.

  13. Effectual switching filter for removing impulse noise using a SCM detector

    Science.gov (United States)

    Yuan, Jin-xia; Zhang, Hong-juan; Ma, Yi-de

    2012-03-01

    An effectual method is proposed to remove impulse noise from corrupted color images. The spiking cortical model (SCM) is adopted as a noise detector to identify noisy pixels in each channel of color images, and detected noise pixels are saved in three marking matrices. According to the three marking matrices, the detected noisy pixels are divided into two types (type I and type II). They are filtered differently: an adaptive median filter is used for type I and an adaptive vector median for type II. Noise-free pixels are left unchanged. Extensive experiments show that the proposed method outperforms most of the other well-known filters in the aspects of both visual and objective quality measures, and this method can also reduce the possibility of generating color artifacts while preserving image details.

  14. Noise removal for medical X-ray images in wavelet domain

    International Nuclear Information System (INIS)

    Wang, Ling; Lu, Jianming; Li, Yeqiu; Yahagi, Takashi; Okamoto, Takahide

    2006-01-01

    Many important problems in engineering and science are well-modeled by Poisson noise, the noise of medical X-ray image is Poisson noise. In this paper, we propose a method of noise removal for degraded medical X-ray image using improved preprocessing and improved BayesShrink (IBS) method in wavelet domain. Firstly, we pre-process the medical X-ray image, Secondly, we apply the Daubechies (db) wavelet transform to medical X-ray image to acquire scaling and wavelet coefficients. Thirdly, we apply the proposed IBS method to process wavelet coefficients. Finally, we compute the inverse wavelet transform for the thresholded coefficeints. Experimental results show that the proposed method always outperforms traditional methods. (author)

  15. Effect of removing the common mode errors on linear regression analysis of noise amplitudes in position time series of a regional GPS network & a case study of GPS stations in Southern California

    Science.gov (United States)

    Jiang, Weiping; Ma, Jun; Li, Zhao; Zhou, Xiaohui; Zhou, Boye

    2018-05-01

    The analysis of the correlations between the noise in different components of GPS stations has positive significance to those trying to obtain more accurate uncertainty of velocity with respect to station motion. Previous research into noise in GPS position time series focused mainly on single component evaluation, which affects the acquisition of precise station positions, the velocity field, and its uncertainty. In this study, before and after removing the common-mode error (CME), we performed one-dimensional linear regression analysis of the noise amplitude vectors in different components of 126 GPS stations with a combination of white noise, flicker noise, and random walking noise in Southern California. The results show that, on the one hand, there are above-moderate degrees of correlation between the white noise amplitude vectors in all components of the stations before and after removal of the CME, while the correlations between flicker noise amplitude vectors in horizontal and vertical components are enhanced from un-correlated to moderately correlated by removing the CME. On the other hand, the significance tests show that, all of the obtained linear regression equations, which represent a unique function of the noise amplitude in any two components, are of practical value after removing the CME. According to the noise amplitude estimates in two components and the linear regression equations, more accurate noise amplitudes can be acquired in the two components.

  16. Effect of drain current on appearance probability and amplitude of random telegraph noise in low-noise CMOS image sensors

    Science.gov (United States)

    Ichino, Shinya; Mawaki, Takezo; Teramoto, Akinobu; Kuroda, Rihito; Park, Hyeonwoo; Wakashima, Shunichi; Goto, Tetsuya; Suwa, Tomoyuki; Sugawa, Shigetoshi

    2018-04-01

    Random telegraph noise (RTN), which occurs in in-pixel source follower (SF) transistors, has become one of the most critical problems in high-sensitivity CMOS image sensors (CIS) because it is a limiting factor of dark random noise. In this paper, the behaviors of RTN toward changes in SF drain current conditions were analyzed using a low-noise array test circuit measurement system with a floor noise of 35 µV rms. In addition to statistical analysis by measuring a large number of transistors (18048 transistors), we also analyzed the behaviors of RTN parameters such as amplitude and time constants in the individual transistors. It is demonstrated that the appearance probability of RTN becomes small under a small drain current condition, although large-amplitude RTN tends to appear in a very small number of cells.

  17. A novel peak detection approach with chemical noise removal using short-time FFT for prOTOF MS data.

    Science.gov (United States)

    Zhang, Shuqin; Wang, Honghui; Zhou, Xiaobo; Hoehn, Gerard T; DeGraba, Thomas J; Gonzales, Denise A; Suffredini, Anthony F; Ching, Wai-Ki; Ng, Michael K; Wong, Stephen T C

    2009-08-01

    Peak detection is a pivotal first step in biomarker discovery from MS data and can significantly influence the results of downstream data analysis steps. We developed a novel automatic peak detection method for prOTOF MS data, which does not require a priori knowledge of protein masses. Random noise is removed by an undecimated wavelet transform and chemical noise is attenuated by an adaptive short-time discrete Fourier transform. Isotopic peaks corresponding to a single protein are combined by extracting an envelope over them. Depending on the S/N, the desired peaks in each individual spectrum are detected and those with the highest intensity among their peak clusters are recorded. The common peaks among all the spectra are identified by choosing an appropriate cut-off threshold in the complete linkage hierarchical clustering. To remove the 1 Da shifting of the peaks, the peak corresponding to the same protein is determined as the detected peak with the largest number among its neighborhood. We validated this method using a data set of serial peptide and protein calibration standards. Compared with MoverZ program, our new method detects more peaks and significantly enhances S/N of the peak after the chemical noise removal. We then successfully applied this method to a data set from prOTOF MS spectra of albumin and albumin-bound proteins from serum samples of 59 patients with carotid artery disease compared to vascular disease-free patients to detect peaks with S/N> or =2. Our method is easily implemented and is highly effective to define peaks that will be used for disease classification or to highlight potential biomarkers.

  18. Removing Eddy-current probe wobble noise from steam generator tubes testing using wavelet transform

    International Nuclear Information System (INIS)

    Lopez, Luiz Antonio Negro Martin; Ting, Daniel Kao Sun; Upadhyaya, Belle R.

    2005-01-01

    One of the most import nondestructive evaluation (NDE) applied to steam generator tubes inspection is the electromagnetic Eddy-Current testing (ECT). The signals generated in this NDE, in general, contain many noises which make difficult the interpretation and analysis of ECT signals. One of the noises present in the signals is the probe wobble noise, which is caused by the existing slack between the probe and the tube. In this work, Wavelet Transform (WT) is used in the probe wobble de-noising. WT is a relatively recent mathematical tool, which allows local analysis of non stationary signals such as ECT signals. This is a great advantage of WT when compared with other analysis tools such as Fourier Transform. However, using WT involves wavelets and coefficients selection as well as choosing the number of decomposition level needed. This work presents a probe wobble de-noising method when used in conjunction with the traditional ECT evaluation. Comparative results using several WT applied do Eddy-Current signals are presented in a reliable way, in other words, without loss of inherent defect information. A stainless steel tube, with 2 artificial defects generated by electro-erosion, was inspected by a ZETEC MIZ-17ET ECT equipment. The signals were de-noised through several different WT and the results are presented. The method offer good results and is a promising method because allows for the removal of Eddy-Current signals probe wobble effect without loss of essential signal information. (author)

  19. Looking for the Signal: A guide to iterative noise and artefact removal in X-ray tomographic reconstructions of porous geomaterials

    Science.gov (United States)

    Bruns, S.; Stipp, S. L. S.; Sørensen, H. O.

    2017-07-01

    X-ray micro- and nanotomography has evolved into a quantitative analysis tool rather than a mere qualitative visualization technique for the study of porous natural materials. Tomographic reconstructions are subject to noise that has to be handled by image filters prior to quantitative analysis. Typically, denoising filters are designed to handle random noise, such as Gaussian or Poisson noise. In tomographic reconstructions, noise has been projected from Radon space to Euclidean space, i.e. post reconstruction noise cannot be expected to be random but to be correlated. Reconstruction artefacts, such as streak or ring artefacts, aggravate the filtering process so algorithms performing well with random noise are not guaranteed to provide satisfactory results for X-ray tomography reconstructions. With sufficient image resolution, the crystalline origin of most geomaterials results in tomography images of objects that are untextured. We developed a denoising framework for these kinds of samples that combines a noise level estimate with iterative nonlocal means denoising. This allows splitting the denoising task into several weak denoising subtasks where the later filtering steps provide a controlled level of texture removal. We describe a hands-on explanation for the use of this iterative denoising approach and the validity and quality of the image enhancement filter was evaluated in a benchmarking experiment with noise footprints of a varying level of correlation and residual artefacts. They were extracted from real tomography reconstructions. We found that our denoising solutions were superior to other denoising algorithms, over a broad range of contrast-to-noise ratios on artificial piecewise constant signals.

  20. Challenges in noise removal from Doppler spectra acquired by a continuous-wave lidar

    DEFF Research Database (Denmark)

    Angelou, Nikolas; Foroughi Abari, Farzad; Mann, Jakob

    2012-01-01

    are presented. A method for determining the background noise spectrum without interrupting the transmission of the laser beam is described. Moreover, the dependency between the determination of the threshold of a Doppler spectrum with low signal-to-noise ratios and the characteristics of the wind flow......This paper is focused on the required post processing of Doppler spectra, acquired from a continuous-wave coherent lidar at high sampling rates (400 Hz) and under rapid scanning of the laser beam. In particular, the necessary steps followed for extracting the wind speed from such Doppler spectra...... are investigated and a systematic approach for removing the noise is outlined. The suggested post processing procedures are applied to two sample time series acquired by a short-range WindScanner during one second each....

  1. The Discrete Wavelet Transform and Its Application for Noise Removal in Localized Corrosion Measurements

    Directory of Open Access Journals (Sweden)

    Rogelio Ramos

    2017-01-01

    Full Text Available The present work discusses the problem of induced external electrical noise as well as its removal from the electrical potential obtained from Scanning Vibrating Electrode Technique (SVET in the pitting corrosion process of aluminum alloy A96061 in 3.5% NaCl. An accessible and efficient solution of this problem is presented with the use of virtual instrumentation (VI, embedded systems, and the discrete wavelet transform (DWT. The DWT is a computational algorithm for digital processing that allows obtaining electrical noise with Signal to Noise Ratio (SNR superior to those obtained with Lock-In Amplifier equipment. The results show that DWT and the threshold method are efficient and powerful alternatives to carry out electrical measurements of potential signals from localized corrosion processes measured by SVET.

  2. Block matching 3D random noise filtering for absorption optical projection tomography

    International Nuclear Information System (INIS)

    Fumene Feruglio, P; Vinegoni, C; Weissleder, R; Gros, J; Sbarbati, A

    2010-01-01

    Absorption and emission optical projection tomography (OPT), alternatively referred to as optical computed tomography (optical-CT) and optical-emission computed tomography (optical-ECT), are recently developed three-dimensional imaging techniques with value for developmental biology and ex vivo gene expression studies. The techniques' principles are similar to the ones used for x-ray computed tomography and are based on the approximation of negligible light scattering in optically cleared samples. The optical clearing is achieved by a chemical procedure which aims at substituting the cellular fluids within the sample with a cell membranes' index matching solution. Once cleared the sample presents very low scattering and is then illuminated with a light collimated beam whose intensity is captured in transillumination mode by a CCD camera. Different projection images of the sample are subsequently obtained over a 360 0 full rotation, and a standard backprojection algorithm can be used in a similar fashion as for x-ray tomography in order to obtain absorption maps. Because not all biological samples present significant absorption contrast, it is not always possible to obtain projections with a good signal-to-noise ratio, a condition necessary to achieve high-quality tomographic reconstructions. Such is the case for example, for early stage's embryos. In this work we demonstrate how, through the use of a random noise removal algorithm, the image quality of the reconstructions can be considerably improved even when the noise is strongly present in the acquired projections. Specifically, we implemented a block matching 3D (BM3D) filter applying it separately on each acquired transillumination projection before performing a complete three-dimensional tomographical reconstruction. To test the efficiency of the adopted filtering scheme, a phantom and a real biological sample were processed. In both cases, the BM3D filter led to a signal-to-noise ratio increment of over 30 d

  3. Clustered DPCM with removing noise spectra for the lossless compression of hyperspectral images

    Science.gov (United States)

    Wu, Jiaji; Xu, Jianglei

    2013-10-01

    The clustered DPCM (C-DPCM) lossless compression method by Jarno et al. for hyperspectral images achieved a good compression effect. It can be divided into three components: clustering, prediction, and coding. In the prediction part, it solves a multiple linear regression model for each of the clusters in every band. Without considering the effect of noise spectra, there is still room for improvement. This paper proposes a C-DPCM method with Removing Noise Spectra (C-DPCM-RNS) for the lossless compression of hyperspectral images. C-DPCM-RNS's prediction part consists of two-times trainings. The prediction coefficients obtained from the first training will be used in the linear predictor to compute all the predicted values and then the difference between original and predicted values in current band of current class. Only the non-noise spectra are used in the second training. The resulting prediction coefficients from the second training will be used for prediction and sent to the decoder. The two-times trainings remove part of the interference of noise spectra, and reaches a better compression effect than other methods based on regression prediction.

  4. Super fast physical-random number generation using laser diode frequency noises

    Science.gov (United States)

    Ushiki, Tetsuro; Doi, Kohei; Maehara, Shinya; Sato, Takashi; Ohkawa, Masashi; Ohdaira, Yasuo

    2011-02-01

    Random numbers can be classified as either pseudo- or physical-random in character. Pseudo-random numbers' periodicity renders them inappropriate for use in cryptographic applications, but naturally-generated physical-random numbers have no calculable periodicity, thereby making them ideally-suited to the task. The laser diode naturally produces a wideband "noise" signal that is believed to have tremendous capacity and great promise, for the rapid generation of physical-random numbers for use in cryptographic applications. We measured a laser diode's output, at a fast photo detector and generated physical-random numbers from frequency noises. We then identified and evaluated the binary-number-line's statistical properties. The result shows that physical-random number generation, at speeds as high as 40Gbps, is obtainable, using the laser diode's frequency noise characteristic.

  5. Noise removal using factor analysis of dynamic structures: application to cardiac gated studies.

    Science.gov (United States)

    Bruyant, P P; Sau, J; Mallet, J J

    1999-10-01

    Factor analysis of dynamic structures (FADS) facilitates the extraction of relevant data, usually with physiologic meaning, from a dynamic set of images. The result of this process is a set of factor images and curves plus some residual activity. The set of factor images and curves can be used to retrieve the original data with reduced noise using an inverse factor analysis process (iFADS). This improvement in image quality is expected because the inverse process does not use the residual activity, assumed to be made of noise. The goal of this work is to quantitate and assess the efficiency of this method on gated cardiac images. A computer simulation of a planar cardiac gated study was performed. The simulated images were added with noise and processed by the FADS-iFADS program. The signal-to-noise ratios (SNRs) were compared between original and processed data. Planar gated cardiac studies from 10 patients were tested. The data processed by FADS-iFADS were subtracted to the original data. The result of the substraction was studied to evaluate its noisy nature. The SNR is about five times greater after the FADS-iFADS process. The difference between original and processed data is noise only, i.e., processed data equals original data minus some white noise. The FADS-iFADS process is successful in the removal of an important part of the noise and therefore is a tool to improve the image quality of cardiac images. This tool does not decrease the spatial resolution (compared with smoothing filters) and does not lose details (compared with frequential filters). Once the number of factors is chosen, this method is not operator dependent.

  6. 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.

  7. 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.

  8. Realistic noise-tolerant randomness amplification using finite number of devices

    Science.gov (United States)

    Brandão, Fernando G. S. L.; Ramanathan, Ravishankar; Grudka, Andrzej; Horodecki, Karol; Horodecki, Michał; Horodecki, Paweł; Szarek, Tomasz; Wojewódka, Hanna

    2016-04-01

    Randomness is a fundamental concept, with implications from security of modern data systems, to fundamental laws of nature and even the philosophy of science. Randomness is called certified if it describes events that cannot be pre-determined by an external adversary. It is known that weak certified randomness can be amplified to nearly ideal randomness using quantum-mechanical systems. However, so far, it was unclear whether randomness amplification is a realistic task, as the existing proposals either do not tolerate noise or require an unbounded number of different devices. Here we provide an error-tolerant protocol using a finite number of devices for amplifying arbitrary weak randomness into nearly perfect random bits, which are secure against a no-signalling adversary. The correctness of the protocol is assessed by violating a Bell inequality, with the degree of violation determining the noise tolerance threshold. An experimental realization of the protocol is within reach of current technology.

  9. Noise-aware dictionary-learning-based sparse representation framework for detection and removal of single and combined noises from ECG signal.

    Science.gov (United States)

    Satija, Udit; Ramkumar, Barathram; Sabarimalai Manikandan, M

    2017-02-01

    Automatic electrocardiogram (ECG) signal enhancement has become a crucial pre-processing step in most ECG signal analysis applications. In this Letter, the authors propose an automated noise-aware dictionary learning-based generalised ECG signal enhancement framework which can automatically learn the dictionaries based on the ECG noise type for effective representation of ECG signal and noises, and can reduce the computational load of sparse representation-based ECG enhancement system. The proposed framework consists of noise detection and identification, noise-aware dictionary learning, sparse signal decomposition and reconstruction. The noise detection and identification is performed based on the moving average filter, first-order difference, and temporal features such as number of turning points, maximum absolute amplitude, zerocrossings, and autocorrelation features. The representation dictionary is learned based on the type of noise identified in the previous stage. The proposed framework is evaluated using noise-free and noisy ECG signals. Results demonstrate that the proposed method can significantly reduce computational load as compared with conventional dictionary learning-based ECG denoising approaches. Further, comparative results show that the method outperforms existing methods in automatically removing noises such as baseline wanders, power-line interference, muscle artefacts and their combinations without distorting the morphological content of local waves of ECG signal.

  10. An adaptive image sparse reconstruction method combined with nonlocal similarity and cosparsity for mixed Gaussian-Poisson noise removal

    Science.gov (United States)

    Chen, Yong-fei; Gao, Hong-xia; Wu, Zi-ling; Kang, Hui

    2018-01-01

    Compressed sensing (CS) has achieved great success in single noise removal. However, it cannot restore the images contaminated with mixed noise efficiently. This paper introduces nonlocal similarity and cosparsity inspired by compressed sensing to overcome the difficulties in mixed noise removal, in which nonlocal similarity explores the signal sparsity from similar patches, and cosparsity assumes that the signal is sparse after a possibly redundant transform. Meanwhile, an adaptive scheme is designed to keep the balance between mixed noise removal and detail preservation based on local variance. Finally, IRLSM and RACoSaMP are adopted to solve the objective function. Experimental results demonstrate that the proposed method is superior to conventional CS methods, like K-SVD and state-of-art method nonlocally centralized sparse representation (NCSR), in terms of both visual results and quantitative measures.

  11. Structure-Based Low-Rank Model With Graph Nuclear Norm Regularization for Noise Removal.

    Science.gov (United States)

    Ge, Qi; Jing, Xiao-Yuan; Wu, Fei; Wei, Zhi-Hui; Xiao, Liang; Shao, Wen-Ze; Yue, Dong; Li, Hai-Bo

    2017-07-01

    Nonlocal image representation methods, including group-based sparse coding and block-matching 3-D filtering, have shown their great performance in application to low-level tasks. The nonlocal prior is extracted from each group consisting of patches with similar intensities. Grouping patches based on intensity similarity, however, gives rise to disturbance and inaccuracy in estimation of the true images. To address this problem, we propose a structure-based low-rank model with graph nuclear norm regularization. We exploit the local manifold structure inside a patch and group the patches by the distance metric of manifold structure. With the manifold structure information, a graph nuclear norm regularization is established and incorporated into a low-rank approximation model. We then prove that the graph-based regularization is equivalent to a weighted nuclear norm and the proposed model can be solved by a weighted singular-value thresholding algorithm. Extensive experiments on additive white Gaussian noise removal and mixed noise removal demonstrate that the proposed method achieves a better performance than several state-of-the-art algorithms.

  12. Fast random-number generation using a diode laser's frequency noise characteristic

    Science.gov (United States)

    Takamori, Hiroki; Doi, Kohei; Maehara, Shinya; Kawakami, Kohei; Sato, Takashi; Ohkawa, Masashi; Ohdaira, Yasuo

    2012-02-01

    Random numbers can be classified as either pseudo- or physical-random, in character. Pseudo-random numbers are generated by definite periodicity, so, their usefulness in cryptographic applications is somewhat limited. On the other hand, naturally-generated physical-random numbers have no calculable periodicity, thereby making them ideal for the task. Diode lasers' considerable wideband noise gives them tremendous capacity for generating physical-random numbers, at a high rate of speed. We measured a diode laser's output with a fast photo detector, and evaluated the binary-numbers from the diode laser's frequency noise characteristics. We then identified and evaluated the binary-number-line's statistical properties. We also investigate the possibility that much faster physical-random number parallel-generation is possible, using separate outputs of different optical-path length and character, which we refer to as "coherence collapse".

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

    Science.gov (United States)

    Huang, Lei

    2015-01-01

    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. PMID:26437409

  14. 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 are init...... 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...

  15. 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 ...

  16. Wavelet theory applied to remove noise and movement artifacts from images

    International Nuclear Information System (INIS)

    Blanco, S.; Cabrejas, M.L.; Carpintiero, S.; Costa, A.; Stenborg, J.

    2002-01-01

    : The signal and noise ratio of NM images corresponding to patients with Alzheimer and Parkinsons disease was improved and the movement artifacts were removed from the images. Due to the nature of this disease, patients tend to move, producing difficulty in the interpretation of the low blood flow areas. Other tedious methods, that correct movement using the sinogram data are not as efficient and need big experience to evaluate if the procedure has been successful. Since this is a post processing method, it avoids acquisition repetition when the patient moved during the study

  17. Suppression of thermal noise in a non-Markovian random velocity field

    International Nuclear Information System (INIS)

    Ueda, Masahiko

    2016-01-01

    We study the diffusion of Brownian particles in a Gaussian random velocity field with short memory. By extending the derivation of an effective Fokker–Planck equation for the Lanvegin equation with weakly colored noise to a random velocity-field problem, we find that the effect of thermal noise on particles is suppressed by the existence of memory. We also find that the renormalization effect for the relative diffusion of two particles is stronger than that for single-particle diffusion. The results are compared with those of molecular dynamics simulations. (paper: classical statistical mechanics, equilibrium and non-equilibrium)

  18. A Regular k-Shrinkage Thresholding Operator for the Removal of Mixed Gaussian-Impulse Noise

    Directory of Open Access Journals (Sweden)

    Han Pan

    2017-01-01

    Full Text Available The removal of mixed Gaussian-impulse noise plays an important role in many areas, such as remote sensing. However, traditional methods may be unaware of promoting the degree of the sparsity adaptively after decomposing into low rank component and sparse component. In this paper, a new problem formulation with regular spectral k-support norm and regular k-support l1 norm is proposed. A unified framework is developed to capture the intrinsic sparsity structure of all two components. To address the resulting problem, an efficient minimization scheme within the framework of accelerated proximal gradient is proposed. This scheme is achieved by alternating regular k-shrinkage thresholding operator. Experimental comparison with the other state-of-the-art methods demonstrates the efficacy of the proposed method.

  19. An effective approach to attenuate random noise based on compressive sensing and curvelet transform

    International Nuclear Information System (INIS)

    Liu, Wei; Cao, Siyuan; Zu, Shaohuan; Chen, Yangkang

    2016-01-01

    Random noise attenuation is an important step in seismic data processing. In this paper, we propose a novel denoising approach based on compressive sensing and the curvelet transform. We formulate the random noise attenuation problem as an L _1 norm regularized optimization problem. We propose to use the curvelet transform as the sparse transform in the optimization problem to regularize the sparse coefficients in order to separate signal and noise and to use the gradient projection for sparse reconstruction (GPSR) algorithm to solve the formulated optimization problem with an easy implementation and a fast convergence. We tested the performance of our proposed approach on both synthetic and field seismic data. Numerical results show that the proposed approach can effectively suppress the distortion near the edge of seismic events during the noise attenuation process and has high computational efficiency compared with the traditional curvelet thresholding and iterative soft thresholding based denoising methods. Besides, compared with f-x deconvolution, the proposed denoising method is capable of eliminating the random noise more effectively while preserving more useful signals. (paper)

  20. Random attractors for stochastic lattice reversible Gray-Scott systems with additive noise

    Directory of Open Access Journals (Sweden)

    Hongyan Li

    2015-10-01

    Full Text Available In this article, we prove the existence of a random attractor of the stochastic three-component reversible Gray-Scott system on infinite lattice with additive noise. We use a transformation of addition involved with Ornstein-Uhlenbeck process, for proving the pullback absorbing property and the pullback asymptotic compactness of the reaction diffusion system with cubic nonlinearity.

  1. Covariance-Based Estimation from Multisensor Delayed Measurements with Random Parameter Matrices and Correlated Noises

    Directory of Open Access Journals (Sweden)

    R. Caballero-Águila

    2014-01-01

    Full Text Available The optimal least-squares linear estimation problem is addressed for a class of discrete-time multisensor linear stochastic systems subject to randomly delayed measurements with different delay rates. For each sensor, a different binary sequence is used to model the delay process. The measured outputs are perturbed by both random parameter matrices and one-step autocorrelated and cross correlated noises. Using an innovation approach, computationally simple recursive algorithms are obtained for the prediction, filtering, and smoothing problems, without requiring full knowledge of the state-space model generating the signal process, but only the information provided by the delay probabilities and the mean and covariance functions of the processes (signal, random parameter matrices, and noises involved in the observation model. The accuracy of the estimators is measured by their error covariance matrices, which allow us to analyze the estimator performance in a numerical simulation example that illustrates the feasibility of the proposed algorithms.

  2. A novel method to remove GPR background noise based on the similarity of non-neighboring regions

    Science.gov (United States)

    Montiel-Zafra, V.; Canadas-Quesada, F. J.; Vera-Candeas, P.; Ruiz-Reyes, N.; Rey, J.; Martinez, J.

    2017-09-01

    Ground penetrating radar (GPR) is a non-destructive technique that has been widely used in many areas of research, such as landmine detection or subsurface anomalies, where it is required to locate targets embedded within a background medium. One of the major challenges in the research of GPR data remains the improvement of the image quality of stone materials by means of detection of true anisotropies since most of the errors are caused by an incorrect interpretation by the users. However, it is complicated due to the interference of the horizontal background noise, e.g., the air-ground interface, that reduces the high-resolution quality of radargrams. Thus, weak or deep anisotropies are often masked by this type of noise. In order to remove the background noise obtained by GPR, this work proposes a novel background removal method assuming that the horizontal noise shows repetitive two-dimensional regions along the movement of the GPR antenna. Specifically, the proposed method, based on the non-local similarity of regions over the distance, computes similarities between different regions of the same depth in order to identify most repetitive regions using a criterion to avoid closer regions. Evaluations are performed using a set of synthetic and real GPR data. Experimental results show that the proposed method obtains promising results compared to the classic background removal techniques and the most recently published background removal methods.

  3. Photoplethysmograph signal reconstruction based on a novel motion artifact detection-reduction approach. Part II: Motion and noise artifact removal.

    Science.gov (United States)

    Salehizadeh, S M A; Dao, Duy K; Chong, Jo Woon; McManus, David; Darling, Chad; Mendelson, Yitzhak; Chon, Ki H

    2014-11-01

    We introduce a new method to reconstruct motion and noise artifact (MNA) contaminated photoplethysmogram (PPG) data. A method to detect MNA corrupted data is provided in a companion paper. Our reconstruction algorithm is based on an iterative motion artifact removal (IMAR) approach, which utilizes the singular spectral analysis algorithm to remove MNA artifacts so that the most accurate estimates of uncorrupted heart rates (HRs) and arterial oxygen saturation (SpO2) values recorded by a pulse oximeter can be derived. Using both computer simulations and three different experimental data sets, we show that the proposed IMAR approach can reliably reconstruct MNA corrupted data segments, as the estimated HR and SpO2 values do not significantly deviate from the uncorrupted reference measurements. Comparison of the accuracy of reconstruction of the MNA corrupted data segments between our IMAR approach and the time-domain independent component analysis (TD-ICA) is made for all data sets as the latter method has been shown to provide good performance. For simulated data, there were no significant differences in the reconstructed HR and SpO2 values starting from 10 dB down to -15 dB for both white and colored noise contaminated PPG data using IMAR; for TD-ICA, significant differences were observed starting at 10 dB. Two experimental PPG data sets were created with contrived MNA by having subjects perform random forehead and rapid side-to-side finger movements show that; the performance of the IMAR approach on these data sets was quite accurate as non-significant differences in the reconstructed HR and SpO2 were found compared to non-contaminated reference values, in most subjects. In comparison, the accuracy of the TD-ICA was poor as there were significant differences in reconstructed HR and SpO2 values in most subjects. For non-contrived MNA corrupted PPG data, which were collected with subjects performing walking and stair climbing tasks, the IMAR significantly

  4. Modeling random telegraph signal noise in CMOS image sensor under low light based on binomial distribution

    International Nuclear Information System (INIS)

    Zhang Yu; Wang Guangyi; Lu Xinmiao; Hu Yongcai; Xu Jiangtao

    2016-01-01

    The random telegraph signal noise in the pixel source follower MOSFET is the principle component of the noise in the CMOS image sensor under low light. In this paper, the physical and statistical model of the random telegraph signal noise in the pixel source follower based on the binomial distribution is set up. The number of electrons captured or released by the oxide traps in the unit time is described as the random variables which obey the binomial distribution. As a result, the output states and the corresponding probabilities of the first and the second samples of the correlated double sampling circuit are acquired. The standard deviation of the output states after the correlated double sampling circuit can be obtained accordingly. In the simulation section, one hundred thousand samples of the source follower MOSFET have been simulated, and the simulation results show that the proposed model has the similar statistical characteristics with the existing models under the effect of the channel length and the density of the oxide trap. Moreover, the noise histogram of the proposed model has been evaluated at different environmental temperatures. (paper)

  5. The augmented lagrange multipliers method for matrix completion from corrupted samplings with application to mixed Gaussian-impulse noise removal.

    Directory of Open Access Journals (Sweden)

    Fan Meng

    Full Text Available This paper studies the problem of the restoration of images corrupted by mixed Gaussian-impulse noise. In recent years, low-rank matrix reconstruction has become a research hotspot in many scientific and engineering domains such as machine learning, image processing, computer vision and bioinformatics, which mainly involves the problem of matrix completion and robust principal component analysis, namely recovering a low-rank matrix from an incomplete but accurate sampling subset of its entries and from an observed data matrix with an unknown fraction of its entries being arbitrarily corrupted, respectively. Inspired by these ideas, we consider the problem of recovering a low-rank matrix from an incomplete sampling subset of its entries with an unknown fraction of the samplings contaminated by arbitrary errors, which is defined as the problem of matrix completion from corrupted samplings and modeled as a convex optimization problem that minimizes a combination of the nuclear norm and the l(1-norm in this paper. Meanwhile, we put forward a novel and effective algorithm called augmented Lagrange multipliers to exactly solve the problem. For mixed Gaussian-impulse noise removal, we regard it as the problem of matrix completion from corrupted samplings, and restore the noisy image following an impulse-detecting procedure. Compared with some existing methods for mixed noise removal, the recovery quality performance of our method is dominant if images possess low-rank features such as geometrically regular textures and similar structured contents; especially when the density of impulse noise is relatively high and the variance of Gaussian noise is small, our method can outperform the traditional methods significantly not only in the simultaneous removal of Gaussian noise and impulse noise, and the restoration ability for a low-rank image matrix, but also in the preservation of textures and details in the image.

  6. 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.

  7. Near real-time noise removal for the Monterey Ocean Bottom Broadband (MOBB) seismic station data

    Science.gov (United States)

    Guinois, M.; Zheng, Z.; Taira, T.; Romanowicz, B. A.

    2012-12-01

    universal TF's (one for the period before the change and one after) are therefore defined and utilized for systematic noise removal. We demonstrate the effectiveness of the technique by applying the cleaned MOBB data to moment tensor inversion of all Mw4.0+ and many Mw 3.5+ events in Northern and Central California in 2009-2012. In addition, we also try to process the MOBB data before 2009. Although the TF is less coherent during the autonomous period of operation due to various problems with one or the other of the instruments, there is potential for application to at least part of the data. Because the vertical component TF is so stable, it can be computed in advance, and the noise removal can be done routinely in near real-time ( with ~8 minutes delay), which is sufficient for routine regional moment tensor determination. This procedure is in the process of implementation in the northern California real time earthquake notification system.

  8. Integration of motion energy from overlapping random background noise increases perceived speed of coherently moving stimuli.

    Science.gov (United States)

    Chuang, Jason; Ausloos, Emily C; Schwebach, Courtney A; Huang, Xin

    2016-12-01

    The perception of visual motion can be profoundly influenced by visual context. To gain insight into how the visual system represents motion speed, we investigated how a background stimulus that did not move in a net direction influenced the perceived speed of a center stimulus. Visual stimuli were two overlapping random-dot patterns. The center stimulus moved coherently in a fixed direction, whereas the background stimulus moved randomly. We found that human subjects perceived the speed of the center stimulus to be significantly faster than its veridical speed when the background contained motion noise. Interestingly, the perceived speed was tuned to the noise level of the background. When the speed of the center stimulus was low, the highest perceived speed was reached when the background had a low level of motion noise. As the center speed increased, the peak perceived speed was reached at a progressively higher background noise level. The effect of speed overestimation required the center stimulus to overlap with the background. Increasing the background size within a certain range enhanced the effect, suggesting spatial integration. The speed overestimation was significantly reduced or abolished when the center stimulus and the background stimulus had different colors, or when they were placed at different depths. When the center- and background-stimuli were perceptually separable, speed overestimation was correlated with perceptual similarity between the center- and background-stimuli. These results suggest that integration of motion energy from random motion noise has a significant impact on speed perception. Our findings put new constraints on models regarding the neural basis of speed perception. Copyright © 2016 the American Physiological Society.

  9. A semi-supervised method to detect seismic random noise with fuzzy GK clustering

    International Nuclear Information System (INIS)

    Hashemi, Hosein; Javaherian, Abdolrahim; Babuska, Robert

    2008-01-01

    We present a new method to detect random noise in seismic data using fuzzy Gustafson–Kessel (GK) clustering. First, using an adaptive distance norm, a matrix is constructed from the observed seismic amplitudes. The next step is to find centres of ellipsoidal clusters and construct a partition matrix which determines the soft decision boundaries between seismic events and random noise. The GK algorithm updates the cluster centres in order to iteratively minimize the cluster variance. Multiplication of the fuzzy membership function with values of each sample yields new sections; we name them 'clustered sections'. The seismic amplitude values of the clustered sections are given in a way to decrease the level of noise in the original noisy seismic input. In pre-stack data, it is essential to study the clustered sections in a f–k domain; finding the quantitative index for weighting the post-stack data needs a similar approach. Using the knowledge of a human specialist together with the fuzzy unsupervised clustering, the method is a semi-supervised random noise detection. The efficiency of this method is investigated on synthetic and real seismic data for both pre- and post-stack data. The results show a significant improvement of the input noisy sections without harming the important amplitude and phase information of the original data. The procedure for finding the final weights of each clustered section should be carefully done in order to keep almost all the evident seismic amplitudes in the output section. The method interactively uses the knowledge of the seismic specialist in detecting the noise

  10. Reduction of Musical Noise in Spectral Subtraction Method Using Subframe Phase Randomization

    Energy Technology Data Exchange (ETDEWEB)

    Seok, J.W.; Bae, K.S. [Kyungpook National University, Taegu (Korea)

    1999-06-01

    The Subframe phase randomization method is applied to the spectral subtraction method to reduce the musical noise in nonvoicing region after speech enhancement. The musical noise in the spectral subtraction method is the result of the narrowband tonal components that appearing somewhat periodically in the spectrogram of unvoiced and silence regions. Thus each synthesis frame in nonvoicing region is divided into several subframes to broaden the narrowband spectrum, and then phases of silence and unvoiced regions are randomized to eliminate the tonal components in the spectrum while keeping the shape of the amplitude spectrum. Performance assessments based on visual inspection of spectrogram, objective measure, and informal subjective listening tests demonstrate the superiority of the proposed algorithm. (author). 7 refs., 5 figs.

  11. Algorithm for removing the noise from γ energy spectrum by analyzing the evolution of the wavelet transform maxima across scales

    International Nuclear Information System (INIS)

    Li Tianduo; Xiao Gang; Di Yuming; Han Feng; Qiu Xiaoling

    1999-01-01

    The γ energy spectrum is expanded in allied energy-frequency space. By the different characterization of the evolution of wavelet transform modulus maxima across scales between energy spectrum and noise, the algorithm for removing the noise from γ energy spectrum by analyzing the evolution of the wavelet transform maxima across scales is presented. The results show, in contrast to the methods in energy space or in frequency space, the method has the advantages that the peak of energy spectrum can be indicated accurately and the energy spectrum can be reconstructed with a good approximation

  12. Removal of jitter noise in 3D shape recovery from image focus by using Kalman filter.

    Science.gov (United States)

    Jang, Hoon-Seok; Muhammad, Mannan Saeed; Choi, Tae-Sun

    2018-02-01

    In regard to Shape from Focus, one critical factor impacting system application is mechanical vibration of the translational stage causing jitter noise along the optical axis. This noise is not detectable by simply observing the image. However, when focus measures are applied, inaccuracies in the depth occur. In this article, jitter noise and focus curves are modeled by Gaussian distribution and quadratic function, respectively. Then Kalman filter is designed and applied to eliminate this noise in the focus curves, as a post-processing step after the focus measure application. Experiments are implemented with simulated objects and real objects to show usefulness of proposed algorithm. © 2017 Wiley Periodicals, Inc.

  13. Multi-frequencies ECT algorithms to remove sodium noise in ISI of ferromagnetic SG tubes of FBR

    International Nuclear Information System (INIS)

    Mihalache, Ovidiu

    2012-01-01

    The paper presents developments and application of multi-frequency eddy current to be used during In-Service Inspection (ISI) of ferromagnetic steam generator (SG) tubes of Fast Breeder Reactors (FBR). Signal enhancement by means of multi-frequency ECT techniques are validated through 3D simulations of both signals and noise due to sodium forms around SG tube or SP. The purpose of such algorithms is to remove from ECT signal the electromagnetic noise resulting from sodium accumulated outside of SG tubes after SG vessel draining. Finite element method (FEM) simulations are used to analyse different sodium build-up scenarios observed experimentally, and to determine optimal multi-frequency ECT algorithms to suppress the most efficiently sodium noise. Also a new 'window multi-frequency' algorithm is applied and validated using 3-dimensional FEM simulations of SP and sodium forms. (author)

  14. Electronic device increases threshold sensitivity and removes noise from FM communications receiver

    Science.gov (United States)

    Conrad, W. M.; Loch, F. J.

    1971-01-01

    Threshold extension device connected between demodulator output and filter output minimizes clicking noise. Device consists of click-eliminating signal transfer channel with follow-and-hold circuit and detector for sensing click impulses. Final output consists of signal plus low level noise without high amplitude impulses.

  15. Separation of random telegraph sSignals from 1/f noise in MOSFETs under constant and switched bias conditions

    NARCIS (Netherlands)

    Kolhatkar, J.S.; Vandamme, L.K.J.; Salm, Cora; Wallinga, Hans

    2004-01-01

    The low-frequency noise power spectrum of small dimension MOSFETs is dominated by Lorentzians arising from random telegraph signals (RTS). The low-frequency noise is observed to decrease when the devices are periodically switched 'off'. The technique of determining the statistical lifetimes and

  16. Total Variation Based Parameter-Free Model for Impulse Noise Removal

    DEFF Research Database (Denmark)

    Sciacchitano, Federica; Dong, Yiqiu; Andersen, Martin Skovgaard

    2017-01-01

    We propose a new two-phase method for reconstruction of blurred images corrupted by impulse noise. In the first phase, we use a noise detector to identify the pixels that are contaminated by noise, and then, in the second phase, we reconstruct the noisy pixels by solving an equality constrained...... total variation minimization problem that preserves the exact values of the noise-free pixels. For images that are only corrupted by impulse noise (i. e., not blurred) we apply the semismooth Newton's method to a reduced problem, and if the images are also blurred, we solve the equality constrained...... reconstruction problem using a first-order primal-dual algorithm. The proposed model improves the computational efficiency (in the denoising case) and has the advantage of being regularization parameter-free. Our numerical results suggest that the method is competitive in terms of its restoration capabilities...

  17. Iterative noise removal from temperature and density profiles in the TJ-II Thomson scattering

    International Nuclear Information System (INIS)

    Farias, G.; Dormido-Canto, S.; Vega, J.; Santos, M.; Pastor, I.; Fingerhuth, S.; Ascencio, J.

    2014-01-01

    TJ-II Thomson Scattering diagnostic provides temperature and density profiles of plasma. The CCD camera acquires images that are corrupted with some kind of noise called stray-light. This noise degrades both image contrast and measurement accuracy, which could produce unreliable profiles of the diagnostic. So far, several approaches have been applied in order to decrease the noise in the TJ-II Thomson scattering images. Since the presence of the noise is not global but located in some particular regions of the image, advanced processing techniques are needed. However such methods require of manual fine-tuning of parameters to reach a good performance. In this contribution, an iterative image processing approach is applied in order to reduce the stray light effects in the images of the TJ-II Thomson scattering diagnostic. The proposed solution describes how the noise can be iteratively reduced in the images when a key parameter is automatically adjusted during the iterative process

  18. Iterative noise removal from temperature and density profiles in the TJ-II Thomson scattering

    Energy Technology Data Exchange (ETDEWEB)

    Farias, G., E-mail: gonzalo.farias@ucv.cl [Pontificia Universidad Católica de Valparaíso, Av. Brasil 2147, Valparaíso (Chile); Dormido-Canto, S., E-mail: sebas@dia.uned.es [Departamento de Informática y Automática, UNED, 28040 Madrid (Spain); Vega, J., E-mail: jesus.vega@ciemat.es [Asociación EURATOM/CIEMAT para Fusión, Avd. Complutense 22, 28040 Madrid (Spain); Santos, M., E-mail: msantos@ucm.es [Departamento de Arquitectura de Computadores y Automática, Universidad Complutense de Madrid, 28040 Madrid (Spain); Pastor, I., E-mail: ignacio.pastor@ciemat.es [Asociación EURATOM/CIEMAT para Fusión, Avd. Complutense 22, 28040 Madrid (Spain); Fingerhuth, S., E-mail: sebastian.fingerhuth@ucv.cl [Pontificia Universidad Católica de Valparaíso, Av. Brasil 2147, Valparaíso (Chile); Ascencio, J., E-mail: j_ascencio21@hotmail.com [Pontificia Universidad Católica de Valparaíso, Av. Brasil 2147, Valparaíso (Chile)

    2014-05-15

    TJ-II Thomson Scattering diagnostic provides temperature and density profiles of plasma. The CCD camera acquires images that are corrupted with some kind of noise called stray-light. This noise degrades both image contrast and measurement accuracy, which could produce unreliable profiles of the diagnostic. So far, several approaches have been applied in order to decrease the noise in the TJ-II Thomson scattering images. Since the presence of the noise is not global but located in some particular regions of the image, advanced processing techniques are needed. However such methods require of manual fine-tuning of parameters to reach a good performance. In this contribution, an iterative image processing approach is applied in order to reduce the stray light effects in the images of the TJ-II Thomson scattering diagnostic. The proposed solution describes how the noise can be iteratively reduced in the images when a key parameter is automatically adjusted during the iterative process.

  19. Adaptive filtration of speech signals in the presence of correlated noise with random variation of probabilistic characteristics

    OpenAIRE

    M. O. Partala; S. Ya. Zhuk

    2007-01-01

    On the base of mixed Markoff process in discrete time optimal and quasioptimal algorithms is designed for adaptive filtration of speech signals in the presence of correlated noise with random variation of probabilistic characteristics.

  20. 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.

  1. Cat Swarm Optimization Based Functional Link Artificial Neural Network Filter for Gaussian Noise Removal from Computed Tomography Images

    Directory of Open Access Journals (Sweden)

    M. Kumar

    2016-01-01

    Full Text Available Gaussian noise is one of the dominant noises, which degrades the quality of acquired Computed Tomography (CT image data. It creates difficulties in pathological identification or diagnosis of any disease. Gaussian noise elimination is desirable to improve the clarity of a CT image for clinical, diagnostic, and postprocessing applications. This paper proposes an evolutionary nonlinear adaptive filter approach, using Cat Swarm Functional Link Artificial Neural Network (CS-FLANN to remove the unwanted noise. The structure of the proposed filter is based on the Functional Link Artificial Neural Network (FLANN and the Cat Swarm Optimization (CSO is utilized for the selection of optimum weight of the neural network filter. The applied filter has been compared with the existing linear filters, like the mean filter and the adaptive Wiener filter. The performance indices, such as peak signal to noise ratio (PSNR, have been computed for the quantitative analysis of the proposed filter. The experimental evaluation established the superiority of the proposed filtering technique over existing methods.

  2. Quantum-noise randomized data encryption for wavelength-division-multiplexed fiber-optic networks

    International Nuclear Information System (INIS)

    Corndorf, Eric; Liang Chuang; Kanter, Gregory S.; Kumar, Prem; Yuen, Horace P.

    2005-01-01

    We demonstrate high-rate randomized data-encryption through optical fibers using the inherent quantum-measurement noise of coherent states of light. Specifically, we demonstrate 650 Mbit/s data encryption through a 10 Gbit/s data-bearing, in-line amplified 200-km-long line. In our protocol, legitimate users (who share a short secret key) communicate using an M-ry signal set while an attacker (who does not share the secret key) is forced to contend with the fundamental and irreducible quantum-measurement noise of coherent states. Implementations of our protocol using both polarization-encoded signal sets as well as polarization-insensitive phase-keyed signal sets are experimentally and theoretically evaluated. Different from the performance criteria for the cryptographic objective of key generation (quantum key-generation), one possible set of performance criteria for the cryptographic objective of data encryption is established and carefully considered

  3. Random noise suppression of seismic data using non-local Bayes algorithm

    Science.gov (United States)

    Chang, De-Kuan; Yang, Wu-Yang; Wang, Yi-Hui; Yang, Qing; Wei, Xin-Jian; Feng, Xiao-Ying

    2018-02-01

    For random noise suppression of seismic data, we present a non-local Bayes (NL-Bayes) filtering algorithm. The NL-Bayes algorithm uses the Gaussian model instead of the weighted average of all similar patches in the NL-means algorithm to reduce the fuzzy of structural details, thereby improving the denoising performance. In the denoising process of seismic data, the size and the number of patches in the Gaussian model are adaptively calculated according to the standard deviation of noise. The NL-Bayes algorithm requires two iterations to complete seismic data denoising, but the second iteration makes use of denoised seismic data from the first iteration to calculate the better mean and covariance of the patch Gaussian model for improving the similarity of patches and achieving the purpose of denoising. Tests with synthetic and real data sets demonstrate that the NL-Bayes algorithm can effectively improve the SNR and preserve the fidelity of seismic data.

  4. Evaluation of domain randomness in periodically poled lithium niobate by diffraction noise measurement.

    Science.gov (United States)

    Dwivedi, Prashant Povel; Choi, Hee Joo; Kim, Byoung Joo; Cha, Myoungsik

    2013-12-16

    Random duty-cycle errors (RDE) in ferroelectric quasi-phase-matching (QPM) devices not only affect the frequency conversion efficiency, but also generate non-phase-matched parasitic noise that can be detrimental to some applications. We demonstrate an accurate but simple method for measuring the RDE in periodically poled lithium niobate. Due to the equivalence between the undepleted harmonic generation spectrum and the diffraction pattern from the QPM grating, we employed linear diffraction measurement which is much simpler than tunable harmonic generation experiments [J. S. Pelc, et al., Opt. Lett.36, 864-866 (2011)]. As a result, we could relate the RDE for the QPM device to the relative noise intensity between the diffraction orders.

  5. PHYCAA: Data-driven measurement and removal of physiological noise in BOLD fMRI

    DEFF Research Database (Denmark)

    Churchill, Nathan W.; Yourganov, Grigori; Spring, Robyn

    2012-01-01

    , autocorrelated physiological noise sources with reproducible spatial structure, using an adaptation of Canonical Correlation Analysis performed in a split-half resampling framework. The technique is able to identify physiological effects with vascular-linked spatial structure, and an intrinsic dimensionality...... with physiological noise, and real data-driven model prediction and reproducibility, for both block and event-related task designs. This is demonstrated compared to no physiological noise correction, and to the widely used RETROICOR (Glover et al., 2000) physiological denoising algorithm, which uses externally...

  6. SPDEs with α-Stable Lévy Noise: A Random Field Approach

    Directory of Open Access Journals (Sweden)

    Raluca M. Balan

    2014-01-01

    Full Text Available This paper is dedicated to the study of a nonlinear SPDE on a bounded domain in Rd, with zero initial conditions and Dirichlet boundary, driven by an α-stable Lévy noise Z with α∈(0,2, α≠1, and possibly nonsymmetric tails. To give a meaning to the concept of solution, we develop a theory of stochastic integration with respect to this noise. The idea is to first solve the equation with “truncated” noise (obtained by removing from Z the jumps which exceed a fixed value K, yielding a solution uK, and then show that the solutions uL,L>K coincide on the event t≤τK, for some stopping times τK converging to infinity. A similar idea was used in the setting of Hilbert-space valued processes. A major step is to show that the stochastic integral with respect to ZK satisfies a pth moment inequality. This inequality plays the same role as the Burkholder-Davis-Gundy inequality in the theory of integration with respect to continuous martingales.

  7. Unsupervised detection and removal of muscle artifacts from scalp EEG recordings using canonical correlation analysis, wavelets and random forests.

    Science.gov (United States)

    Anastasiadou, Maria N; Christodoulakis, Manolis; Papathanasiou, Eleftherios S; Papacostas, Savvas S; Mitsis, Georgios D

    2017-09-01

    This paper proposes supervised and unsupervised algorithms for automatic muscle artifact detection and removal from long-term EEG recordings, which combine canonical correlation analysis (CCA) and wavelets with random forests (RF). The proposed algorithms first perform CCA and continuous wavelet transform of the canonical components to generate a number of features which include component autocorrelation values and wavelet coefficient magnitude values. A subset of the most important features is subsequently selected using RF and labelled observations (supervised case) or synthetic data constructed from the original observations (unsupervised case). The proposed algorithms are evaluated using realistic simulation data as well as 30min epochs of non-invasive EEG recordings obtained from ten patients with epilepsy. We assessed the performance of the proposed algorithms using classification performance and goodness-of-fit values for noisy and noise-free signal windows. In the simulation study, where the ground truth was known, the proposed algorithms yielded almost perfect performance. In the case of experimental data, where expert marking was performed, the results suggest that both the supervised and unsupervised algorithm versions were able to remove artifacts without affecting noise-free channels considerably, outperforming standard CCA, independent component analysis (ICA) and Lagged Auto-Mutual Information Clustering (LAMIC). The proposed algorithms achieved excellent performance for both simulation and experimental data. Importantly, for the first time to our knowledge, we were able to perform entirely unsupervised artifact removal, i.e. without using already marked noisy data segments, achieving performance that is comparable to the supervised case. Overall, the results suggest that the proposed algorithms yield significant future potential for improving EEG signal quality in research or clinical settings without the need for marking by expert

  8. An Adaptive Filter for the Removal of Drifting Sinusoidal Noise Without a Reference.

    Science.gov (United States)

    Kelly, John W; Siewiorek, Daniel P; Smailagic, Asim; Wang, Wei

    2016-01-01

    This paper presents a method for filtering sinusoidal noise with a variable bandwidth filter that is capable of tracking a sinusoid's drifting frequency. The method, which is based on the adaptive noise canceling (ANC) technique, will be referred to here as the adaptive sinusoid canceler (ASC). The ASC eliminates sinusoidal contamination by tracking its frequency and achieving a narrower bandwidth than typical notch filters. The detected frequency is used to digitally generate an internal reference instead of relying on an external one as ANC filters typically do. The filter's bandwidth adjusts to achieve faster and more accurate convergence. In this paper, the focus of the discussion and the data is physiological signals, specifically electrocorticographic (ECoG) neural data contaminated with power line noise, but the presented technique could be applicable to other recordings as well. On simulated data, the ASC was able to reliably track the noise's frequency, properly adjust its bandwidth, and outperform comparative methods including standard notch filters and an adaptive line enhancer. These results were reinforced by visual results obtained from real ECoG data. The ASC showed that it could be an effective method for increasing signal to noise ratio in the presence of drifting sinusoidal noise, which is of significant interest for biomedical applications.

  9. New high resolution Random Telegraph Noise (RTN) characterization method for resistive RAM

    Science.gov (United States)

    Maestro, M.; Diaz, J.; Crespo-Yepes, A.; Gonzalez, M. B.; Martin-Martinez, J.; Rodriguez, R.; Nafria, M.; Campabadal, F.; Aymerich, X.

    2016-01-01

    Random Telegraph Noise (RTN) is one of the main reliability problems of resistive switching-based memories. To understand the physics behind RTN, a complete and accurate RTN characterization is required. The standard equipment used to analyse RTN has a typical time resolution of ∼2 ms which prevents evaluating fast phenomena. In this work, a new RTN measurement procedure, which increases the measurement time resolution to 2 μs, is proposed. The experimental set-up, together with the recently proposed Weighted Time Lag (W-LT) method for the analysis of RTN signals, allows obtaining a more detailed and precise information about the RTN phenomenon.

  10. Multiplicative noise removal through fractional order tv-based model and fast numerical schemes for its approximation

    Science.gov (United States)

    Ullah, Asmat; Chen, Wen; Khan, Mushtaq Ahmad

    2017-07-01

    This paper introduces a fractional order total variation (FOTV) based model with three different weights in the fractional order derivative definition for multiplicative noise removal purpose. The fractional-order Euler Lagrange equation which is a highly non-linear partial differential equation (PDE) is obtained by the minimization of the energy functional for image restoration. Two numerical schemes namely an iterative scheme based on the dual theory and majorization- minimization algorithm (MMA) are used. To improve the restoration results, we opt for an adaptive parameter selection procedure for the proposed model by applying the trial and error method. We report numerical simulations which show the validity and state of the art performance of the fractional-order model in visual improvement as well as an increase in the peak signal to noise ratio comparing to corresponding methods. Numerical experiments also demonstrate that MMAbased methodology is slightly better than that of an iterative scheme.

  11. Timing of urinary catheter removal after uncomplicated total abdominal hysterectomy: a prospective randomized trial.

    Science.gov (United States)

    Ahmed, Magdy R; Sayed Ahmed, Waleed A; Atwa, Khaled A; Metwally, Lobna

    2014-05-01

    To assess whether immediate (0h), intermediate (after 6h) or delayed (after 24h) removal of an indwelling urinary catheter after uncomplicated abdominal hysterectomy can affect the rate of re-catheterization due to urinary retention, rate of urinary tract infection, ambulation time and length of hospital stay. Prospective randomized controlled trial conducted at Suez Canal University Hospital, Egypt. Two hundred and twenty-one women underwent total abdominal hysterectomy for benign gynecological diseases and were randomly allocated into three groups. Women in group A (73 patients) had their urinary catheter removed immediately after surgery. Group B (81 patients) had the catheter removed 6h post-operatively while in group C (67 patients) the catheter was removed after 24h. The main outcome measures were the frequency of urinary retention, urinary tract infections, ambulation time and length of hospital stay. There was a significantly higher number of urinary retention episodes requiring re-catheterization in the immediate removal group compared to the intermediate and delayed removal groups (16.4% versus 2.5% and 0% respectively). Delayed urinary catheter removal was associated with a higher incidence of urinary tract infections (15%), delayed ambulation time (10.3h) and longer hospital stay (5.6 days) compared to the early (1.4%, 4.1h and 3.2 days respectively) and intermediate (3.7%, 6.8h and 3.4 days respectively) removal groups. Removal of the urinary catheter 6h postoperatively appears to be more advantageous than early or late removal in cases of uncomplicated total abdominal hysterectomy. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  12. Noise removal in extended depth of field microscope images through nonlinear signal processing.

    Science.gov (United States)

    Zahreddine, Ramzi N; Cormack, Robert H; Cogswell, Carol J

    2013-04-01

    Extended depth of field (EDF) microscopy, achieved through computational optics, allows for real-time 3D imaging of live cell dynamics. EDF is achieved through a combination of point spread function engineering and digital image processing. A linear Wiener filter has been conventionally used to deconvolve the image, but it suffers from high frequency noise amplification and processing artifacts. A nonlinear processing scheme is proposed which extends the depth of field while minimizing background noise. The nonlinear filter is generated via a training algorithm and an iterative optimizer. Biological microscope images processed with the nonlinear filter show a significant improvement in image quality and signal-to-noise ratio over the conventional linear filter.

  13. Doubling the Spectrum of Time-Domain Induced Polarization: Removal of Harmonic Noise and Self-Potential Drift

    Science.gov (United States)

    Fiandaca, G.; Olsson, P. I.; Auken, E.; Larsen, J. J.; Maurya, P. K.; Dahlin, T.

    2015-12-01

    The extraction of spectral information in the inversion process of time-domain (TD) induced polarization (IP) data is changing the use of the IP method. Data interpretation is evolving from a qualitative description of the soil, able only to discriminate the presence of contrasts in chargeability parameters, towards a quantitative analysis of the investigated media, which allows soil-type characterization. Two major limitations restrict the extraction of the spectral information of TDIP data in the field: i) the difficulty of acquiring reliable early-time measurements, in the millisecond range and ii) the self-potential drift in the measured potentials distorting the shape of the late time IP decays, in the second range. For measuring at early-times, we developed a new method for removing the powerline noise contained in the data through a model-based approach, localizing the fundamental frequency of the powerline signal in the full-waveform IP recordings. By this, we cancel both the fundamental signal and its harmonics. This noise cancellation allows the use of earlier and narrower gates, down to a few milliseconds after the current turn-off. Even earlier gates can be measured but they will be inductively "contaminated" which we at present want to avoid. A proper removal of the self-potential drift present between the potential electrodes is essential for preserving the shape of the TD decays, especially for late times. Usually constant or linear drift-removal algorithms are used, but these algorithms fail in removing the background potentials due to the polarization of the electrodes previously used for current injection. We developed a drift-removal scheme that model the polarization effect and efficiently allows for preserving the shape of the IP decays. The removal of both the harmonic noise and self-potential drift allows for doubling the usable range of TDIP data to more than three decades in time (corresponding to three decays in frequency), and will

  14. Removal versus retention of cerclage in preterm premature rupture of membranes: a randomized controlled trial.

    Science.gov (United States)

    Galyean, Anna; Garite, Thomas J; Maurel, Kimberly; Abril, Diana; Adair, Charles D; Browne, Paul; Combs, C Andrew; How, Helen; Iriye, Brian K; Kominiarek, Michelle; Lu, George; Luthy, David; Miller, Hugh; Nageotte, Michael; Ozcan, Tulin; Porto, Manuel; Ramirez, Mildred; Sawai, Shirley; Sorokin, Yoram

    2014-10-01

    The decision of whether to retain or remove a previously placed cervical cerclage in women who subsequently rupture fetal membranes in a premature gestation is controversial and all studies to date are retrospective. We performed a multicenter randomized controlled trial of removal vs retention of cerclage in these patients to determine whether leaving the cerclage in place prolonged gestation and/or increased the risk of maternal or fetal infection. A prospective randomized multicenter trial of 27 hospitals was performed. Patients included were those with cerclage placement at ≤23 weeks 6 days in singleton or twin pregnancies, with subsequent spontaneous rupture of membranes between 22 weeks 0 days and 32 weeks 6 days. Patients were randomized to retention or removal of cerclage. Patients were then expectantly managed and delivered only for evidence of labor, chorioamnionitis, fetal distress, or other medical or obstetrical indications. Management after 34 weeks was at the clinician's discretion. The initial sample size calculation determined that a total of 142 patients should be included but after a second interim analysis, futility calculations determined that the conditional power for showing statistical significance after randomizing 142 patients for the primary outcome of prolonging pregnancy was 22.8%. Thus the study was terminated after a total of 56 subjects were randomized with complete data available for analysis, 32 to removal and 24 to retention of cerclage. There was no statistical significance in primary outcome of prolonging pregnancy by 1 week comparing the 2 groups (removal 18/32, 56.3%; retention 11/24, 45.8%) P = .59; or chorioamnionitis (removal 8/32, 25.0%; retention 10/24, 41.7%) P = .25, respectively. There was no statistical difference in composite neonatal outcomes (removal 16/33, 50%; retention 17/30, 56%), fetal/neonatal death (removal 4/33, 12%; retention 5/30, 16%); or gestational age at delivery (removal mean 200 days; retention

  15. Prediction of interior noise due to random acoustic or turbulent boundary layer excitation using statistical energy analysis

    Science.gov (United States)

    Grosveld, Ferdinand W.

    1990-01-01

    The feasibility of predicting interior noise due to random acoustic or turbulent boundary layer excitation was investigated in experiments in which a statistical energy analysis model (VAPEPS) was used to analyze measurements of the acceleration response and sound transmission of flat aluminum, lucite, and graphite/epoxy plates exposed to random acoustic or turbulent boundary layer excitation. The noise reduction of the plate, when backed by a shallow cavity and excited by a turbulent boundary layer, was predicted using a simplified theory based on the assumption of adiabatic compression of the fluid in the cavity. The predicted plate acceleration response was used as input in the noise reduction prediction. Reasonable agreement was found between the predictions and the measured noise reduction in the frequency range 315-1000 Hz.

  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. Affectively salient meaning in random noise: a task sensitive to psychosis liability.

    Science.gov (United States)

    Galdos, Mariana; Simons, Claudia; Fernandez-Rivas, Aranzazu; Wichers, Marieke; Peralta, Concepción; Lataster, Tineke; Amer, Guillermo; Myin-Germeys, Inez; Allardyce, Judith; Gonzalez-Torres, Miguel Angel; van Os, Jim

    2011-11-01

    Stable differences in the tendency to attribute meaning and emotional value to experience may represent an indicator of liability to psychosis. A brief task was developed assessing variation in detecting affectively meaningful speech (speech illusion) in neutral random signals (white noise) and the degree to which this was associated with psychometric and familial vulnerability for psychosis. Thirty patients, 28 of their siblings, and 307 controls participated. The rate of speech illusion was compared between cases and controls. In controls, the association between speech illusion and interview-based positive schizotypy was assessed. The hypothesis of a dose-response increase in rate of speech illusion across increasing levels of familial vulnerability for psychosis (controls, siblings of patients, and patients) was examined. Patients were more likely to display speech illusions than controls (odds ratio [OR] = 4.0, 95% confidence interval [CI] = 1.4-11.7), also after controlling for neurocognitive variables (OR = 3.8, 95% CI = 1.04-14.1). The case-control difference was more accentuated for speech illusion perceived as affectively salient (positively or negatively appraised) than for neutrally appraised speech illusions. Speech illusion in the controls was strongly associated with positive schizotypy but not with negative schizotypy. In addition, the rate of speech illusion increased with increasing level of familial risk for psychotic disorder. The data suggest that the white noise task may be sensitive to psychometric and familial vulnerability for psychosis associated with alterations in top-down processing and/or salience attribution.

  18. Random noise can help to improve synchronization of excimer laser pulses.

    Science.gov (United States)

    Mingesz, Róbert; Barna, Angéla; Gingl, Zoltán; Mellár, János

    2016-02-01

    Recently, we have reported on a compact microcontroller-based unit developed to accurately synchronize excimer laser pulses (Mingesz et al. 2012 Fluct. Noise Lett. 11, 1240007 (doi:10.1142/S021947751240007X)). We have shown that dithering based on random jitter noise plus pseudorandom numbers can be used in the digital control system to radically reduce the long-term drift of the laser pulse from the trigger and to improve the accuracy of the synchronization. In this update paper, we present our new experimental results obtained by the use of the delay-controller unit to tune the timing of a KrF excimer laser as an addition to our previous numerical simulation results. The hardware was interfaced to the laser using optical signal paths in order to reduce sensitivity to electromagnetic interference and the control algorithm tested by simulations was applied in the experiments. We have found that the system is able to reduce the delay uncertainty very close to the theoretical limit and performs well in real applications. The simple, compact and flexible system is universal enough to also be used in various multidisciplinary applications.

  19. 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.

  20. A Nonlinear Diffusion Equation-Based Model for Ultrasound Speckle Noise Removal

    Science.gov (United States)

    Zhou, Zhenyu; Guo, Zhichang; Zhang, Dazhi; Wu, Boying

    2018-04-01

    Ultrasound images are contaminated by speckle noise, which brings difficulties in further image analysis and clinical diagnosis. In this paper, we address this problem in the view of nonlinear diffusion equation theories. We develop a nonlinear diffusion equation-based model by taking into account not only the gradient information of the image, but also the information of the gray levels of the image. By utilizing the region indicator as the variable exponent, we can adaptively control the diffusion type which alternates between the Perona-Malik diffusion and the Charbonnier diffusion according to the image gray levels. Furthermore, we analyze the proposed model with respect to the theoretical and numerical properties. Experiments show that the proposed method achieves much better speckle suppression and edge preservation when compared with the traditional despeckling methods, especially in the low gray level and low-contrast regions.

  1. A Pipelining Implementation for Parsing X-ray Diffraction Source Data and Removing the Background Noise

    International Nuclear Information System (INIS)

    Bauer, Michael A; Biem, Alain; McIntyre, Stewart; Xie Yuzhen

    2010-01-01

    Synchrotrons can be used to generate X-rays in order to probe materials at the atomic level. One approach is to use X-ray diffraction (XRD) to do this. The data from an XRD experiment consists of a sequence of digital image files which for a single scan could consist of hundreds or even thousands of digital images. Existing analysis software processes these images individually sequentially and is usually used after the experiment is completed. The results from an XRD detector can be thought of as a sequence of images, generated during the scan by the X-ray beam. If these images could be analyzed in near real-time, the results could be sent to the researcher running the experiment and used to improve the overall experimental process and results. In this paper, we report on a stream processing application to remove background from XRD images using a pipelining implementation. We describe our implementation techniques of using IBM Infosphere Streams for parsing XRD source data and removing the background. We present experimental results showing the super-linear speedup attained over a purely sequential version of the algorithm on a quad-core machine. These results demonstrate the potential of making good use of multi-cores for high-performance stream processing of XRD images.

  2. 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.

  3. Surface detection performance evaluation of pseudo-random noise continuous wave laser radar

    Science.gov (United States)

    Mitev, Valentin; Matthey, Renaud; Pereira do Carmo, Joao

    2017-11-01

    A number of space missions (including in the ESA Exploration Programme) foreseen a use of laser radar sensor (or lidar) for determination of range between spacecrafts or between spacecraft and ground surface (altimetry). Such sensors need to be compact, robust and power efficient, at the same time with high detection performance. These requirements can be achieved with a Pseudo-Random Noise continuous wave lidar (PRN cw lidar). Previous studies have pointed to the advantages of this lidar with respect to space missions, but they also identified its limitations in high optical background. The progress of the lasers and the detectors in the near IR spectral range requires a re-evaluation of the PRN cw lidar potential. Here we address the performances of this lidar for surface detection (altimetry) in planetary missions. The evaluation is based on the following system configuration: (i) A cw fiber amplifier as lidar transmitter. The seeding laser exhibits a single-frequency spectral line, with subsequent amplitude modulation. The fiber amplifier allows high output power level, keeping the spectral characteristics and the modulation of the seeding light input. (ii) An avalanche photodiode in photon counting detection; (iii) Measurement scenarios representative for Earth, Mercury and Mars.

  4. Asynchronous Advanced Encryption Standard Hardware with Random Noise Injection for Improved Side-Channel Attack Resistance

    Directory of Open Access Journals (Sweden)

    Siva Kotipalli

    2014-01-01

    (SCA resistance. These designs are based on a delay-insensitive (DI logic paradigm known as null convention logic (NCL, which supports useful properties for resisting SCAs including dual-rail encoding, clock-free operation, and monotonic transitions. Potential benefits include reduced and more uniform switching activities and reduced signal-to-noise (SNR ratio. A novel method to further augment NCL AES hardware with random voltage scaling technique is also presented for additional security. Thereby, the proposed components leak significantly less side-channel information than conventional clocked approaches. To quantitatively verify such improvements, functional verification and WASSO (weighted average simultaneous switching output analysis have been carried out on both conventional synchronous approach and the proposed NCL based approach using Mentor Graphics ModelSim and Xilinx simulation tools. Hardware implementation has been carried out on both designs exploiting a specified side-channel attack standard evaluation FPGA board, called SASEBO-GII, and the corresponding power waveforms for both designs have been collected. Along with the results of software simulations, we have analyzed the collected waveforms to validate the claims related to benefits of the proposed cryptohardware design approach.

  5. Strong Tracking Filter for Nonlinear Systems with Randomly Delayed Measurements and Correlated Noises

    Directory of Open Access Journals (Sweden)

    Hongtao Yang

    2018-01-01

    Full Text Available This paper proposes a novel strong tracking filter (STF, which is suitable for dealing with the filtering problem of nonlinear systems when the following cases occur: that is, the constructed model does not match the actual system, the measurements have the one-step random delay, and the process and measurement noises are correlated at the same epoch. Firstly, a framework of decoupling filter (DF based on equivalent model transformation is derived. Further, according to the framework of DF, a new extended Kalman filtering (EKF algorithm via using first-order linearization approximation is developed. Secondly, the computational process of the suboptimal fading factor is derived on the basis of the extended orthogonality principle (EOP. Thirdly, the ultimate form of the proposed STF is obtained by introducing the suboptimal fading factor into the above EKF algorithm. The proposed STF can automatically tune the suboptimal fading factor on the basis of the residuals between available and predicted measurements and further the gain matrices of the proposed STF tune online to improve the filtering performance. Finally, the effectiveness of the proposed STF has been proved through numerical simulation experiments.

  6. Propagation of waves in a randomly inhomogeneous medium with strongly developed fluctuations. III. Arbitrary power-law noise correlation function

    International Nuclear Information System (INIS)

    Adzhemyan, L.Ts.; Vasil'ev, A.N.; Pis'mak, Yu.M.

    1988-01-01

    The investigation of the infrared behavior of the propagator of a light wave in a randomly inhomogeneous medium with massless Gaussian noise is continued. The infrared representation of the propagator for correlation function D varphi (k)∼k -2 is generalized to the case of an arbitrary power-law noise correlation function is rigorously established in the first two orders of the infrared asymptotic behavior by construction of a suitable R operation. As a consequence, the results are generalized to the case of critical opalescence, when D varphi (k)∼k -2+η , where η ∼ 0.03 is the Fisher index

  7. Volume Threshold for Chest Tube Removal: A Randomized ‎Controlled Trial

    Directory of Open Access Journals (Sweden)

    Sajad Hatami

    2009-07-01

    Full Text Available Background: Despite importance of chest tube insertion in chest trauma, there is no ‎general agreement on the level of daily volume drainage from chest tube. This study ‎was conducted to compare the effectiveness and safety of chest tube removal at the ‎levels of 150 ml/day and 2oo ml/day. Methods: Eligible patients (138 who needed replacement of chest tube (because of ‎trauma or malignancy were randomized into two groups; control (removal of chest tube ‎when drainage reached to 150 ml/day and trial (removal of chest tube at the level of ‎‎200 ml/day. All patients received standard care during hospital admission and a follow-‎up visit after 7days of discharge from hospital. Patients were then compared in terms of ‎major clinical outcomes using chi-squared and t-test. Results: From the total of 138 patients, 70 and 68 patients were randomized to control ‎‎(G150 and trial (G200 group, respectively. Baseline characteristics were comparable ‎between the two groups. Although the trial group had a shorter mean for length of ‎hospital stay (LOS (4.1 compared to 4.8, p=0.04, their differences in drainage time ‎did not reach to the level of statistical significance (p=0.1. Analysis of data showed no ‎statistically significant differences between the rate of radiological reaccumulation, ‎thoracentesis and decrease in pulmonary sounds (auscultatory, one week after ‎discharge from hospital.‎‏ ‏Conclusions: Compared to a daily volume drainage of 150 ml, removal of chest tube ‎when there is 200 ml/day is safe and will even result in a shorter hospital stay. This in ‎turn leads to a lower cost.‎

  8. Doubling the spectrum of time-domain induced polarization: removal of non-linear self-potential drift, harmonic noise and spikes, tapered gating, and uncertainty estimation

    DEFF Research Database (Denmark)

    Olsson, Per-Ivar; Fiandaca, Gianluca; Larsen, Jakob Juul

    , a logarithmic gate width distribution for optimizing IP data quality and an estimate of gating uncertainty. Additional steps include modelling and cancelling of non-linear background drift and harmonic noise and a technique for efficiently identifying and removing spikes. The cancelling of non-linear background...... drift is based on a Cole-Cole model which effectively handles current induced electrode polarization drift. The model-based cancelling of harmonic noise reconstructs the harmonic noise as a sum of harmonic signals with a common fundamental frequency. After segmentation of the signal and determining....... The processing steps is successfully applied on full field profile data sets. With the model-based cancelling of harmonic noise, the first usable IP gate is moved one decade closer to time zero. Furthermore, with a Cole-Cole background drift model the shape of the response at late times is accurately retrieved...

  9. Scaling in Rate-Changeable Birth and Death Processes with Random Removals

    International Nuclear Information System (INIS)

    Ke Jianhong; Lin Zhenquan; Chen Xiaoshuang

    2009-01-01

    We propose a monomer birth-death model with random removals, in which an aggregate of size k can produce a new monomer at a time-dependent rate I(t)k or lose one monomer at a rate J(t)k, and with a probability P (t) an aggregate of any size is randomly removed. We then analytically investigate the kinetic evolution of the model by means of the rate equation. The results show that the scaling behavior of the aggregate size distribution is dependent crucially on the net birth rate I(t) - J(t) as well as the birth rate I(t). The aggregate size distribution can approach a standard or modified scaling form in some cases, but it may take a scale-free form in other cases. Moreover, the species can survive finally only if either I(t) - J(t) ≥ P (t) or [J(t) + P (t) - I(t)]t ≅ 0 at t >> 1; otherwise, it will become extinct.

  10. Incomplete caries removal and indirect pulp capping in primary molars: a randomized controlled trial.

    Science.gov (United States)

    Bressani, Ana Eliza Lemes; Mariath, Adriela Azevedo Souza; Haas, Alex Nogueira; Garcia-Godoy, Franklin; de Araujo, Fernando Borba

    2013-08-01

    To compare the effect of incomplete caries removal (ICR) and indirect pulp capping (IPC) with calcium hydroxide (CH) or an inert material (wax) on color, consistency and contamination of the remaining dentin of primary molars. This double-blind, parallel-design, randomized controlled trial included 30 children presenting one primary molar with deep caries lesion. Children were randomly assigned after ICR to receive IPC with CH or wax. All teeth were then restored with resin composite. Baseline dentin color and consistency were evaluated after ICR, and dentin samples were collected for contamination analyses using scanning electron microscopy. After 3 months, restorations were removed and the three parameters were re-evaluated. In both groups, dentin became significantly darker after 3 months. No cases of yellow dentin were observed after 3 months with CH compared to 33.3% of the wax cases (P Contamination changed significantly over time in CH and wax without significant difference between groups. It was concluded that CH and wax arrested the carious process of the remaining carious dentin after indirect pulp capping, but CH showed superior dentin color and consistency after 3 months.

  11. Discriminality of statistically independent Gaussian noise tokens and random tone-burst complexes

    NARCIS (Netherlands)

    Goossens, T.L.J.; Par, van de S.L.J.D.E.; Kohlrausch, A.G.; Kollmeier, B.; Klump, G.; Hohmann, V.; Langemann, U.; Mauermann, M.; Uppenkamp, S.; Verhey, J.

    2007-01-01

    Hanna (1984) has shown that noise tokens with a duration of 400 ms are harder to discriminate than noise tokens of 100 ms. This is remarkable because a 400-ms stimulus potentially contains four times as much information for judging dissimilarity than the 100-ms stimulus. Apparently, the ability to

  12. On the ability to discriminate Gaussian-noise tokens or random tone-burst complexes

    NARCIS (Netherlands)

    Goossens, T.L.J.; Par, van de S.L.J.D.E.; Kohlrausch, A.G.

    2008-01-01

    This study investigated factors that influence a listeners' ability to discriminate Gaussian-noise stimuli in a same-different discrimination paradigm. The first experiment showed that discrimination ability increased with bandwidth for noise durations up to 100 ms. Duration had a nonmonotonic

  13. Alkaline Peroxides Versus Sodium Hypochlorite for Removing Denture Biofilm: a Crossover Randomized Trial.

    Science.gov (United States)

    Peracini, Amanda; Regis, Rômulo Rocha; Souza, Raphael Freitas de; Pagnano, Valéria Oliveira; Silva, Cláudia Helena Lovato da; Paranhos, Helena de Freitas Oliveira

    2016-01-01

    This study evaluated the efficacy of cleanser solutions on denture biofilm removal by a crossover randomized clinical trial. Thirty two edentulous patients were instructed to brush their dentures (specific brush and liquid soap) three times a day (after breakfast, lunch and dinner) and to soak them (≥ 8 h) in: (C) control -water; (AP): alkaline peroxide; or (SH) 0.5% sodium hypochlorite. Each solution was used for 21 days (three cycles of 7 days). At the end of each cycle, the inner surfaces of maxillary dentures were disclosed (1% neutral red) and photographed (HX1 - Sony). Areas (total and stained biofilm) were measured (Image Tool software) and the percentage of biofilm calculated as the ratio between the area of the biofilm multiplied by 100 and total surface area of the internal base of the denture. Data were compared by means of generalized estimating equation (α=5%) and multiple comparisons (Bonferroni; α=1.67%). Immersion in SH reduced biofilm (%) (8.3 ± 13.3B) compared to C (18.2 ± 14.9A) and AP (18.2 ± 16.6A). The 0.5% sodium hypochlorite solution was the most efficacious for biofilm removal. Alkaline peroxides may not lead to further biofilm removal in patients with adequate denture maintenance habits.

  14. Efficacy of chemomechanical caries removal in reducing cariogenic microbiota: a randomized clinical trial

    Directory of Open Access Journals (Sweden)

    Michelle Mikhael AMMARI

    2014-08-01

    Full Text Available The aim of this study was to compare the efficacy of chemochemical methods (Carisolv™ and Papacárie® versus the manual method (excavators in reducing the cariogenic microbiota in dentine caries of primary teeth. Forty-six healthy children (5 to 9 years old having at least one primary tooth with a cavitated dentine carious lesion were included in the study. The teeth presented no clinical or radiographic signs of pulpal involvement. The sample of 74 teeth was randomly divided into three different groups: Papacárie® (n = 25, Carisolv™ (n = 27 and Manual (n = 22. Samples of carious and sound dentine were collected with sterile excavators before and after caries removal in the three groups. The dentine samples were transferred to glass tubes containing a 1mL thioglycollate medium used as a carrier and enriched for microbiological detection of mutans streptococci and Lactobacillus spp, after incubation for 6h at room temperature. The minimum detection value for colony forming units (CFU was 3.3 x 102 CFU/ml, and the results were converted into scores from 0 to 4. A significant difference was observed in relation to the microbiological scores before and after caries removal for all methods (Wilcoxon test; p < 0.001. The use of chemomechanical methods for caries removal did not improve the reduction of cariogenic microorganisms in dentine caries lesions, in comparison with manual excavation.

  15. 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.

  16. 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.

  17. The benefits of noise and nonlinearity: Extracting energy from random vibrations

    Energy Technology Data Exchange (ETDEWEB)

    Gammaitoni, Luca, E-mail: luca.gammaitoni@pg.infn.it [NiPS Laboratory, Universita di Perugia, I-06100 Perugia (Italy); Neri, Igor; Vocca, Helios [NiPS Laboratory, Universita di Perugia, I-06100 Perugia (Italy)

    2010-10-05

    Nonlinear behavior is the ordinary feature of the vast majority of dynamical systems and noise is commonly present in any finite temperature physical and chemical system. In this article we briefly review the potentially beneficial outcome of the interplay of noise and nonlinearity by addressing the novel field of vibration energy harvesting. The role of nonlinearity in a piezoelectric harvester oscillator dynamics is modeled with nonlinear stochastic differential equation.

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

    International Nuclear Information System (INIS)

    Theodorsen, A; Garcia, O E; Rypdal, M

    2017-01-01

    Filtered Poisson processes are often used as reference models for intermittent fluctuations in physical systems. Such a process is here 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 lowest order moments, probability density function, auto-correlation function and power spectral density are derived and used to identify and compare the effects of the two different noise terms. Monte-Carlo studies of synthetic time series are used to investigate the accuracy of model parameter estimation and to identify methods for distinguishing the noise types. It is shown that the probability density function and the three lowest order moments provide accurate estimations of the model 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 identifying the noise type. The number of times the signal crosses a prescribed threshold level in the positive direction also promises to be able to differentiate the noise type. (paper)

  19. Doubling the spectrum of time-domain induced polarization by harmonic de-noising, drift correction, spike removal, tapered gating and data uncertainty estimation

    Science.gov (United States)

    Olsson, Per-Ivar; Fiandaca, Gianluca; Larsen, Jakob Juul; Dahlin, Torleif; Auken, Esben

    2016-11-01

    The extraction of spectral information in the inversion process of time-domain (TD) induced polarization (IP) data is changing the use of the TDIP method. Data interpretation is evolving from a qualitative description of the subsurface, able only to discriminate the presence of contrasts in chargeability parameters, towards a quantitative analysis of the investigated media, which allows for detailed soil- and rock-type characterization. Two major limitations restrict the extraction of the spectral information of TDIP data in the field: (i) the difficulty of acquiring reliable early-time measurements in the millisecond range and (ii) the self-potential background drift in the measured potentials distorting the shape of the late-time IP responses, in the second range. Recent developments in TDIP acquisition equipment have given access to full-waveform recordings of measured potentials and transmitted current, opening for a breakthrough in data processing. For measuring at early times, we developed a new method for removing the significant noise from power lines contained in the data through a model-based approach, localizing the fundamental frequency of the power-line signal in the full-waveform IP recordings. By this, we cancel both the fundamental signal and its harmonics. Furthermore, an efficient processing scheme for identifying and removing spikes in TDIP data was developed. The noise cancellation and the de-spiking allow the use of earlier and narrower gates, down to a few milliseconds after the current turn-off. In addition, tapered windows are used in the final gating of IP data, allowing the use of wider and overlapping gates for higher noise suppression with minimal distortion of the signal. For measuring at late times, we have developed an algorithm for removal of the self-potential drift. Usually constant or linear drift-removal algorithms are used, but these algorithms often fail in removing the background potentials present when the electrodes used for

  20. Generalized randomly amplified linear system driven by Gaussian noises: Extreme heavy tail and algebraic correlation decay in plasma turbulence

    International Nuclear Information System (INIS)

    Steinbrecher, Gyoergy; Weyssow, B.

    2004-01-01

    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 β 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

  1. Discriminality of statistically independent Gaussian noise tokens and random tone-burst complexes

    OpenAIRE

    Goossens, T.L.J.; Par, van de, S.L.J.D.E.; Kohlrausch, A.G.; Kollmeier, B.; Klump, G.; Hohmann, V.; Langemann, U.; Mauermann, M.; Uppenkamp, S.; Verhey, J.

    2007-01-01

    Hanna (1984) has shown that noise tokens with a duration of 400 ms are harder to discriminate than noise tokens of 100 ms. This is remarkable because a 400-ms stimulus potentially contains four times as much information for judging dissimilarity than the 100-ms stimulus. Apparently, the ability to use all information in a stimulus is impaired by some kind of limitation, e.g. a memory limitation (cf. Cowan 2000) or a limitation in the ability to allocate attentional resources (cf. Kidd and Wat...

  2. A random-parametric reactor model with direct feedback and non-white noise

    International Nuclear Information System (INIS)

    Sako, O.; Taniguchi, A.; Kuroda, Y.

    1982-01-01

    The effects of multiplicative direct power feedback and non-white reactivity noise on the fluctuations of the neutron density are studied, based on the master equation using the cumulant expansion and the system-size expansion. The results obtained are the following: non-whiteness of reactivity noise reduces the variance of neutron density, as well as the level of the power spectral density. The nonlinear effect of power feedback gives rise to at least a pair of corner frequencies, in contrast to the single corner frequency in linearized case. (author)

  3. Signal processing method for Johnson noise thermometry

    International Nuclear Information System (INIS)

    Hwang, I. G.; Moon, B. S.; Kinser, Rpger

    2003-01-01

    The development of Johnson Noise Thermometry requires a high sensitive preamplifier circuit to pick up the temperature-related noise on the sensing element. However, the random noise generated in this amplification circuit causes a significant erroneous influence to the measurement. This paper describes signal processing mechanism of the Johnson Noise Thermometry system which is underway of development in collaboration between KAERI and ORNL. It adopts two identical amplifier channels and utilizes a digital signal processing technique to remove the independent noise of each channel. The CPSD(Cross Power Spectral Density) function is used to cancel the independent noise and the differentiation of narrow or single frequency peak from the CPSD data separates the common mode electromagnetic interference noise

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. An application of reactor noise techniques to neutron transport problems in a random medium

    International Nuclear Information System (INIS)

    Sahni, D.C.

    1989-01-01

    Neutron transport problems in a random medium are considered by defining a joint Markov process describing the fluctuations of one neutron population and the random changes in the medium. Backward Chapman-Kolmogorov equations are derived which yield an adjoint transport equation for the average neutron density. It is shown that this average density also satisfied the direct transport equation as given by the phenomenological model. (author)

  9. A New Switching-Based Median Filtering Scheme and Algorithm for Removal of High-Density Salt and Pepper Noise in Images

    Directory of Open Access Journals (Sweden)

    Jayaraj V

    2010-01-01

    Full Text Available A new switching-based median filtering scheme for restoration of images that are highly corrupted by salt and pepper noise is proposed. An algorithm based on the scheme is developed. The new scheme introduces the concept of substitution of noisy pixels by linear prediction prior to estimation. A novel simplified linear predictor is developed for this purpose. The objective of the scheme and algorithm is the removal of high-density salt and pepper noise in images. The new algorithm shows significantly better image quality with good PSNR, reduced MSE, good edge preservation, and reduced streaking. The good performance is achieved with reduced computational complexity. A comparison of the performance is made with several existing algorithms in terms of visual and quantitative results. The performance of the proposed scheme and algorithm is demonstrated.

  10. Identification and Removal of High Frequency Temporal Noise in a Nd:YAG Macro-Pulse Laser Assisted with a Diagnostic Streak Camera

    International Nuclear Information System (INIS)

    Kent Marlett; Ke-Xun Sun

    2004-01-01

    This paper discusses the use of a reference streak camera (SC) to diagnose laser performance and guide modifications to remove high frequency noise from Bechtel Nevada's long-pulse laser. The upgraded laser exhibits less than 0.1% high frequency noise in cumulative spectra, exceeding National Ignition Facility (NIF) calibration specifications. Inertial Confinement Fusion (ICF) experiments require full characterization of streak cameras over a wide range of sweep speeds (10 ns to 480 ns). This paradigm of metrology poses stringent spectral requirements on the laser source for streak camera calibration. Recently, Bechtel Nevada worked with a laser vendor to develop a high performance, multi-wavelength Nd:YAG laser to meet NIF calibration requirements. For a typical NIF streak camera with a 4096 x 4096 pixel CCD, the flat field calibration at 30 ns requires a smooth laser spectrum over 33 MHz to 68 GHz. Streak cameras are the appropriate instrumentation for measuring laser amplitude noise at these very high frequencies since the upper end spectral content is beyond the frequency response of typical optoelectronic detectors for a single shot pulse. The SC was used to measure a similar laser at its second harmonic wavelength (532 nm), to establish baseline spectra for testing signal analysis algorithms. The SC was then used to measure the new custom calibration laser. In both spatial-temporal measurements and cumulative spectra, 6-8 GHz oscillations were identified. The oscillations were found to be caused by inter-surface reflections between amplifiers. Additional variations in the SC spectral data were found to result from temperature instabilities in the seeding laser. Based on these findings, laser upgrades were made to remove the high frequency noise from the laser output

  11. Efficacy and mode of action of a noise-sensor light alarm to decrease noise in the pediatric intensive care unit: a prospective, randomized study.

    Science.gov (United States)

    Jousselme, Chloé; Vialet, Renaud; Jouve, Elisabeth; Lagier, Pierre; Martin, Claude; Michel, Fabrice

    2011-03-01

    To determine whether a sound-activated light-alarm device could reduce the noise in the central area of our pediatric intensive care unit and to determine whether this reduction was significant enough to decrease the noise that could be perceived by a patient located in a nearby room. The secondary objective was to determine the mode of action of the device. In a 16-bed pediatric and neonatal intensive care unit, a large and clearly noticeable sound-activated light device was set in the noisiest part of the central area of our unit, and noise measurements were made in the central area and in a nearby room. In a prospective, quasi-experimental design, sound levels were compared across three different situations--no device present, device present and turned on, and device present but turned off--and noise level measurements were made over a total of 18 days. None. Setting a sound-activated light device on or off. When the device was present, the noise was about 2 dB lower in the central area and in a nearby room, but there was no difference in noise level with the device turned on vs. turned off. The noise decrease in the central area was of limited importance but was translated in a nearby room. The sound-activated light device did not directly decrease noise when turned on, but repetition of the visual signal throughout the day raised staff awareness of noise levels over time.

  12. 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

  13. Randomized controlled clinical trial of long-term chemo-mechanical caries removal using PapacarieTM gel

    Directory of Open Access Journals (Sweden)

    Lara Jansiski MOTTA

    2014-07-01

    Full Text Available Objectives: Compare the effectiveness of PapacarieTM gel for the chemo-mechanical removal of carious lesions on primary teeth to conventional caries removal with a low-speed bur with regard to execution time, clinical aspects and radiographic findings. Material and Methods: A randomized controlled clinical trial with a split-mouth design was carried out. The sample was composed of 20 children aged four to seven years, in whom 40 deciduous teeth were randomly divided into two groups: chemo-mechanical caries removal with PapacarieTM and removal of carious dentin with a low-speed bur. Each child underwent both procedures and served as his/her own control. Restorations were performed with glass ionomer cement. The time required to perform the procedure was also analyzed. The patients underwent longitudinal clinical and radiographic follow-up of the restorations. Results: No statistically significant difference between groups was found regarding the time required to perform the procedures and the radiographic follow up. Statistically significant differences between groups were found in the clinical evaluation at 6 and 18 months after treatment. Conclusion: PapacarieTM is as effective as the traditional method for the removal of carious dentin on deciduous teeth, but offers the advantages of the preservation of sound dental tissue as well as the avoidance of sharp rotary instruments and local anesthesia.

  14. Efficient algorithm for baseline wander and powerline noise removal from ECG signals based on discrete Fourier series.

    Science.gov (United States)

    Bahaz, Mohamed; Benzid, Redha

    2018-03-01

    Electrocardiogram (ECG) signals are often contaminated with artefacts and noises which can lead to incorrect diagnosis when they are visually inspected by cardiologists. In this paper, the well-known discrete Fourier series (DFS) is re-explored and an efficient DFS-based method is proposed to reduce contribution of both baseline wander (BW) and powerline interference (PLI) noises in ECG records. In the first step, the determination of the exact number of low frequency harmonics contributing in BW is achieved. Next, the baseline drift is estimated by the sum of all associated Fourier sinusoids components. Then, the baseline shift is discarded efficiently by a subtraction of its approximated version from the original biased ECG signal. Concerning the PLI, the subtraction of the contributing harmonics calculated in the same manner reduces efficiently such type of noise. In addition of visual quality results, the proposed algorithm shows superior performance in terms of higher signal-to-noise ratio and smaller mean square error when faced to the DCT-based algorithm.

  15. Investigation of reactivity change and neutron noise due to random absorber vibrations. 2

    International Nuclear Information System (INIS)

    Barthel, R.

    1984-01-01

    Perturbations of the neutron flux due to stochastically excited vibrations of absorbers have been investigated using a one-dimensional core model with N pointlike absorbers. Taking into account the flux depressions near the absorbers, pronounced peaks in the spectral power densities of the flux fluctuations have been found at multiples of the resonance frequencies in addition to the direct imaging of the resonances of absorber vibrations. Investigation of the space dependence of the corresponding transfer functions has shown that a localization is possible by means of the double frequency effect and that the dispersion of absorber vibrations can be determined by using the triple frequency effect. The conclusions of the paper are qualitatively compared with results of noise measurements at a pressurized water reactor. (author)

  16. An Adaptive Noise Cancellation System Based on Linear and Widely Linear Complex Valued Least Mean Square Algorithms for Removing Electrooculography Artifacts from Electroencephalography Signals

    Directory of Open Access Journals (Sweden)

    Engin Cemal MENGÜÇ

    2018-03-01

    Full Text Available In this study, an adaptive noise cancellation (ANC system based on linear and widely linear (WL complex valued least mean square (LMS algorithms is designed for removing electrooculography (EOG artifacts from electroencephalography (EEG signals. The real valued EOG and EEG signals (Fp1 and Fp2 given in dataset are primarily expressed as a complex valued signal in the complex domain. Then, using the proposed ANC system, the EOG artifacts are eliminated in the complex domain from the EEG signals. Expression of these signals in the complex domain allows us to remove EOG artifacts from two EEG channels simultaneously. Moreover, in this study, it has been shown that the complex valued EEG signal exhibits noncircular behavior, and in the case, the WL-CLMS algorithm enhances the performance of the ANC system compared to real-valued LMS and CLMS algorithms. Simulation results support the proposed approach.

  17. Random noise effects in pulse-mode digital multilayer neural networks.

    Science.gov (United States)

    Kim, Y C; Shanblatt, M A

    1995-01-01

    A pulse-mode digital multilayer neural network (DMNN) based on stochastic computing techniques is implemented with simple logic gates as basic computing elements. The pulse-mode signal representation and the use of simple logic gates for neural operations lead to a massively parallel yet compact and flexible network architecture, well suited for VLSI implementation. Algebraic neural operations are replaced by stochastic processes using pseudorandom pulse sequences. The distributions of the results from the stochastic processes are approximated using the hypergeometric distribution. Synaptic weights and neuron states are represented as probabilities and estimated as average pulse occurrence rates in corresponding pulse sequences. A statistical model of the noise (error) is developed to estimate the relative accuracy associated with stochastic computing in terms of mean and variance. Computational differences are then explained by comparison to deterministic neural computations. DMNN feedforward architectures are modeled in VHDL using character recognition problems as testbeds. Computational accuracy is analyzed, and the results of the statistical model are compared with the actual simulation results. Experiments show that the calculations performed in the DMNN are more accurate than those anticipated when Bernoulli sequences are assumed, as is common in the literature. Furthermore, the statistical model successfully predicts the accuracy of the operations performed in the DMNN.

  18. ELLIPTICAL WEIGHTED HOLICs FOR WEAK LENSING SHEAR MEASUREMENT. III. THE EFFECT OF RANDOM COUNT NOISE ON IMAGE MOMENTS IN WEAK LENSING ANALYSIS

    International Nuclear Information System (INIS)

    Okura, Yuki; Futamase, Toshifumi

    2013-01-01

    This is the third paper on the improvement of systematic errors in weak lensing analysis using an elliptical weight function, referred to as E-HOLICs. In previous papers, we succeeded in avoiding errors that depend on the ellipticity of the background image. In this paper, we investigate the systematic error that depends on the signal-to-noise ratio of the background image. We find that the origin of this error is the random count noise that comes from the Poisson noise of sky counts. The random count noise makes additional moments and centroid shift error, and those first-order effects are canceled in averaging, but the second-order effects are not canceled. We derive the formulae that correct this systematic error due to the random count noise in measuring the moments and ellipticity of the background image. The correction formulae obtained are expressed as combinations of complex moments of the image, and thus can correct the systematic errors caused by each object. We test their validity using a simulated image and find that the systematic error becomes less than 1% in the measured ellipticity for objects with an IMCAT significance threshold of ν ∼ 11.7.

  19. REMOVED: Mindfulness meditation with incarcerated youth: A randomized controlled trial informed by neuropsychosocial theories of adolescence.

    Science.gov (United States)

    Evans-Chase, Michelle

    2015-12-01

    This article has been removed: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal) This meeting abstract has been removed by the Publisher. Due to an administrative error, abstracts that were not presented at the ISDN 2014 meeting were inadvertently published in the meeting's abstract supplement. The Publisher apologizes to the authors and readers for this error. Copyright © 2015. Published by Elsevier Ltd.

  20. 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.

  1. Karhunen-Loève treatment to remove noise and facilitate data analysis in sensing, spectroscopy and other applications.

    Science.gov (United States)

    Zaharov, V V; Farahi, R H; Snyder, P J; Davison, B H; Passian, A

    2014-11-21

    Resolving weak spectral variations in the dynamic response of materials that are either dominated or excited by stochastic processes remains a challenge. Responses that are thermal in origin are particularly relevant examples due to the delocalized nature of heat. Despite its inherent properties in dealing with stochastic processes, the Karhunen-Loève expansion has not been fully exploited in measurement of systems that are driven solely by random forces or can exhibit large thermally driven random fluctuations. Here, we present experimental results and analysis of the archetypes (a) the resonant excitation and transient response of an atomic force microscope probe by the ambient random fluctuations and nanoscale photothermal sample response, and (b) the photothermally scattered photons in pump-probe spectroscopy. In each case, the dynamic process is represented as an infinite series with random coefficients to obtain pertinent frequency shifts and spectral peaks and demonstrate spectral enhancement for a set of compounds including the spectrally complex biomass. The considered cases find important applications in nanoscale material characterization, biosensing, and spectral identification of biological and chemical agents.

  2. 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.

  3. Universal Linear Fit Identification: A Method Independent of Data, Outliers and Noise Distribution Model and Free of Missing or Removed Data Imputation.

    Science.gov (United States)

    Adikaram, K K L B; Hussein, M A; Effenberger, M; Becker, T

    2015-01-01

    Data processing requires a robust linear fit identification method. In this paper, we introduce a non-parametric robust linear fit identification method for time series. The method uses an indicator 2/n to identify linear fit, where n is number of terms in a series. The ratio Rmax of amax - amin and Sn - amin*n and that of Rmin of amax - amin and amax*n - Sn are always equal to 2/n, where amax is the maximum element, amin is the minimum element and Sn is the sum of all elements. If any series expected to follow y = c consists of data that do not agree with y = c form, Rmax > 2/n and Rmin > 2/n imply that the maximum and minimum elements, respectively, do not agree with linear fit. We define threshold values for outliers and noise detection as 2/n * (1 + k1) and 2/n * (1 + k2), respectively, where k1 > k2 and 0 ≤ k1 ≤ n/2 - 1. Given this relation and transformation technique, which transforms data into the form y = c, we show that removing all data that do not agree with linear fit is possible. Furthermore, the method is independent of the number of data points, missing data, removed data points and nature of distribution (Gaussian or non-Gaussian) of outliers, noise and clean data. These are major advantages over the existing linear fit methods. Since having a perfect linear relation between two variables in the real world is impossible, we used artificial data sets with extreme conditions to verify the method. The method detects the correct linear fit when the percentage of data agreeing with linear fit is less than 50%, and the deviation of data that do not agree with linear fit is very small, of the order of ±10-4%. The method results in incorrect detections only when numerical accuracy is insufficient in the calculation process.

  4. Universal Linear Fit Identification: A Method Independent of Data, Outliers and Noise Distribution Model and Free of Missing or Removed Data Imputation.

    Directory of Open Access Journals (Sweden)

    K K L B Adikaram

    Full Text Available Data processing requires a robust linear fit identification method. In this paper, we introduce a non-parametric robust linear fit identification method for time series. The method uses an indicator 2/n to identify linear fit, where n is number of terms in a series. The ratio Rmax of amax - amin and Sn - amin*n and that of Rmin of amax - amin and amax*n - Sn are always equal to 2/n, where amax is the maximum element, amin is the minimum element and Sn is the sum of all elements. If any series expected to follow y = c consists of data that do not agree with y = c form, Rmax > 2/n and Rmin > 2/n imply that the maximum and minimum elements, respectively, do not agree with linear fit. We define threshold values for outliers and noise detection as 2/n * (1 + k1 and 2/n * (1 + k2, respectively, where k1 > k2 and 0 ≤ k1 ≤ n/2 - 1. Given this relation and transformation technique, which transforms data into the form y = c, we show that removing all data that do not agree with linear fit is possible. Furthermore, the method is independent of the number of data points, missing data, removed data points and nature of distribution (Gaussian or non-Gaussian of outliers, noise and clean data. These are major advantages over the existing linear fit methods. Since having a perfect linear relation between two variables in the real world is impossible, we used artificial data sets with extreme conditions to verify the method. The method detects the correct linear fit when the percentage of data agreeing with linear fit is less than 50%, and the deviation of data that do not agree with linear fit is very small, of the order of ±10-4%. The method results in incorrect detections only when numerical accuracy is insufficient in the calculation process.

  5. 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.

  6. Transcranial Random Noise Stimulation-induced plasticity is NMDA-receptor independent but sodium-channel blocker and benzodiazepines sensitive

    Directory of Open Access Journals (Sweden)

    Leila eChaieb

    2015-04-01

    Full Text Available Background: Application of transcranial random noise stimulation (tRNS between 0.1 and 640 Hz of the primary motor cortex (M1 for 10 minutes induces a persistent excitability increase lasting for at least 60 minutes. However, the mechanism of tRNS-induced cortical excitability alterations is not yet fully understood. Objective: The main aim of this study was to get first efficacy data with regard to the possible neuronal effect of tRNS. Methods: Single-pulse transcranial magnetic stimulation (TMS was used to measure levels of cortical excitability before and after combined application of tRNS at an intensity of 1mA for 10mins stimulation duration and a pharmacological agent (or sham on 8 healthy male participants. Results: The sodium channel blocker carbamazepine showed a tendency towards inhibiting MEPs 5-60 mins poststimulation. The GABAA agonist lorazepam suppressed tRNS-induced cortical excitability increases at 0-20 and 60 min time points. The partial NMDA receptor agonist D-cycloserine, the NMDA receptor antagonist dextromethorphan and the D2/D3 receptor agonist ropinirole had no significant effects on the excitability increases seen with tRNS.Conclusions: In contrast to transcranial direct current stimulation (tDCS, aftereffects of tRNS are seem to be not NMDA receptor dependent and can be suppressed by benzodiazepines suggesting that tDCS and tRNS depend upon different mechanisms.

  7. Comparison of bandage contact lens removal on the fourth versus seventh postoperative day after photorefractive keratectomy: A randomized clinical trial.

    Science.gov (United States)

    Mohammadpour, Mehrdad; Shakoor, Delaram; Hashemi, Hassan; Aghaie Meybodi, Mohamad; Rajabi, Fateme; Hosseini, Pegah

    2017-06-01

    To compare the outcomes of bandage contact lens (BCL) removal on the fourth versus seventh post-operative day following photorefractive keratectomy (PRK). This study recruited eyes of patients who underwent PRK surgery. The patients were randomly assigned to 2 groups. In Group 1 BCL was removed on the 4th postoperative day, while in Group 2, BCL was removed on the 7th postoperative day. After BCL removal, patients were asked to express their pain score and eye discomfort. At one and three months follow-up examinations, visual acuity scale was assessed. Slit-lamp examination was performed in all visits to evaluate complications. 260 eyes of 130 patients underwent PRK. The age and sex ratio were not significantly different between the two groups. One month after the surgery, the logMAR uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) were significantly lower in Group 2 (P value = 0.016, 0.001 respectively), however, the UDVA and CDVA were not significantly different after 3 months (P > 0.05). In Group 1, filamentary keratitis (FK) was observed in 10 (7.6%) eyes, 6 (4.61%) eyes were diagnosed with recurrent corneal erosion (RCE) and corneal haze was detected in 3 (2.3%) eyes. However, in Group 2, RCE was observed in 4 (2.3%) and FK was noted in 4 (3.07%) eyes. No haze was seen in Group 2. The difference in rate of complications was statistically significant (14.6% and 6.1% in Groups 1 and 2, respectively, P = 0.02). Pain and eye discomfort scores were not significantly different (P > 0.05). There was no major complications including infectious keratitis in either groups. Following PRK surgery, BCL removal on the seventh postoperative day yields faster visual rehabilitation and lower rate of postoperative complications with no increase in eye pain, discomfort or infection.

  8. Hysteroscopic morcellator for removal of intrauterine polyps and myomas: a randomized controlled pilot study among residents in training.

    Science.gov (United States)

    van Dongen, Heleen; Emanuel, Mark Hans; Wolterbeek, Ron; Trimbos, J Baptist; Jansen, Frank Willem

    2008-01-01

    The purpose of this randomized controlled study was to compare conventional resectoscopy and hysteroscopic morcellation among residents in training (Canadian Task Force classification I). Sixty women with an intrauterine polyp or myoma were randomized to either hysteroscopic removal by conventional resectoscopy or hysteroscopic morcellation performed by 6 residents in training for obstetrics and gynecology (10 procedures per resident). The mean operating time for resectosocpy and morcellation was 17.0 (95% confidence interval [95% CI] 14.1-17.9, standard deviation [SD] 8.4) and 10.6 (95% CI 7.3-14.0, SD 9.5) min, respectively (p = .008). Multiple linear regression analysis showed that operating time increased significantly, for both resectoscopy and morcellator, when volume of intrauterine disorder increased. The use of the hysteroscopic morcellator reduced operating time more than 8 min in comparison to conventional resectoscopy (p learning curve was observed. In conclusion, the hysteroscopic morcellator for removal of intrauterine polyps and myomas offers a good alternative to conventional resectoscopy for residents in training.

  9. Efficacy of chemomechanical caries removal in reducing cariogenic microbiota: a randomized clinical trial

    OpenAIRE

    AMMARI, Michelle Mikhael; MOLITERNO, Luiz Flávio Martins; HIRATA JÚNIOR, Raphael; SÉLLOS, Mariana Canano; SOVIERO, Vera Mendes; COUTINHO FILHO, Wagner Pereira

    2014-01-01

    The aim of this study was to compare the efficacy of chemochemical methods (Carisolv™ and Papacárie®) versus the manual method (excavators) in reducing the cariogenic microbiota in dentine caries of primary teeth. Forty-six healthy children (5 to 9 years old) having at least one primary tooth with a cavitated dentine carious lesion were included in the study. The teeth presented no clinical or radiographic signs of pulpal involvement. The sample of 74 teeth was randomly divided into thr...

  10. A Removable Long-arm Soft Cast to Treat Nondisplaced Pediatric Elbow Fractures: A Randomized, Controlled Trial.

    Science.gov (United States)

    Silva, Mauricio; Sadlik, Gal; Avoian, Tigran; Ebramzadeh, Edward

    2018-04-01

    The ideal type of immobilization for nondisplaced pediatric elbow fractures has not been established. We hypothesized that the use of a long-arm cylinder made of soft cast material will result in similar outcomes to those obtained with a traditional long-arm hard cast. We randomly assigned 100 consecutive children who presented with a closed, nondisplaced, type I supracondylar humeral fracture or an occult, closed, acute elbow injury, to 1 of 2 groups: group A (n=50) received a long-arm, traditional fiberglass (hard) cast. Group B (n=50) received a long-arm, soft fiberglass cast. After 4 weeks, the cast was removed in group A by a member of our staff using a cast saw, and in group B by one of the patient's parents by rolling back the soft fiberglass material. We compared the amount of fracture displacement and/or angulation, recovery of range of motion, elbow pain, and patient satisfaction. There were no instances of unplanned removal of the cast by the patient or parent. No evidence of fracture displacement or angulation was seen in either group. The final carrying angle of the affected elbow was nearly identical of that of the normal, contralateral elbow in both groups (P=0.64). At the latest follow-up appointment, elbows in groups A and B had a similar mean arc of motion (156 vs. 154 degrees; P=0.45), and had achieved identical relative arc of motion of 99.6% and 99.5% of that of the normal, contralateral side, respectively (P=0.94). Main pain scores were low and comparable over the study period. All patients in both groups reported the highest rate of satisfaction at the eighth week of follow-up. The results indicate that children with nondisplaced supracondylar humeral fractures can be successfully managed with the use of a removable long-arm soft cast, maintaining fracture alignment and resulting in comparable rates of range of motion, pain, and patient satisfaction. The use of a removable immobilization that can reliably maintain fracture alignment and

  11. Universal Linear Fit Identification: A Method Independent of Data, Outliers and Noise Distribution Model and Free of Missing or Removed Data Imputation

    Science.gov (United States)

    Adikaram, K. K. L. B.; Becker, T.

    2015-01-01

    Data processing requires a robust linear fit identification method. In this paper, we introduce a non-parametric robust linear fit identification method for time series. The method uses an indicator 2/n to identify linear fit, where n is number of terms in a series. The ratio R max of a max − a min and S n − a min *n and that of R min of a max − a min and a max *n − S n are always equal to 2/n, where a max is the maximum element, a min is the minimum element and S n is the sum of all elements. If any series expected to follow y = c consists of data that do not agree with y = c form, R max > 2/n and R min > 2/n imply that the maximum and minimum elements, respectively, do not agree with linear fit. We define threshold values for outliers and noise detection as 2/n * (1 + k 1 ) and 2/n * (1 + k 2 ), respectively, where k 1 > k 2 and 0 ≤ k 1 ≤ n/2 − 1. Given this relation and transformation technique, which transforms data into the form y = c, we show that removing all data that do not agree with linear fit is possible. Furthermore, the method is independent of the number of data points, missing data, removed data points and nature of distribution (Gaussian or non-Gaussian) of outliers, noise and clean data. These are major advantages over the existing linear fit methods. Since having a perfect linear relation between two variables in the real world is impossible, we used artificial data sets with extreme conditions to verify the method. The method detects the correct linear fit when the percentage of data agreeing with linear fit is less than 50%, and the deviation of data that do not agree with linear fit is very small, of the order of ±10−4%. The method results in incorrect detections only when numerical accuracy is insufficient in the calculation process. PMID:26571035

  12. Noise suppression by noise

    OpenAIRE

    Vilar, J. M. G. (José M. G.), 1972-; 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.

  13. Two Randomized Clinical Studies to Confirm Differential Plaque Removal by Sodium Bicarbonate Dentifrices in a Single Timed Brushing Model.

    Science.gov (United States)

    Mason, Stephen; Karwal, Ritu; Bosma, Mary Lynn

    2017-09-01

    This study evaluated and compared plaque removal efficacy of commercially available dentifrices containing sodium bicarbonate (NaHCO3) to those without NaHCO3 in a single timed brushing clinical study model. Two randomized, examiner-blind, three-period, three-treatment, crossover studies were performed in adults with a mean Turesky modification of the Quigley-Hein Plaque Index (TPI) score of = 2.00. In Study 1, 60 subjects were randomized to commercially available dentifrices containing: (i) 67% NaHCO3 plus 1425 ppm fluoride (F) as sodium fluoride (NaF); (ii) 45% NaHCO3 plus 1425 ppm F as NaF; or (iii) 0% NaHCO3 plus silica and 1450 ppm F as NaF. In Study 2, 55 subjects were randomized to commercially available dentifrices containing: (i) 67% NaHCO3 plus 1425 ppm F as NaF; (ii) 0% NaHCO3 plus silica and 1400 ppm F as amine F/stannous F; or (iii) 0% NaHCO3 plus chlorhexidine/aluminum lactate and silica with 1360 ppm F as aluminum F. In both studies, subjects brushed their teeth for one timed minute under supervised conditions. Plaque was assessed pre- and post-brushing according to a six-site modification of the TPI. Mean TPI score was analyzed using an analysis of covariance model with treatment and study period as fixed effects, subject as a random variable, and pre-brushing score as a covariate. In both studies, mean TPI score decreased in all groups post-brushing compared with pre-brushing. In Study 1, statistically significant improvements in mean TPI score were reported with the 67% and 45% NaHCO3 dentifrices compared with the 0% NaHCO3 dentifrice (p = 0.0003 and p = 0.0005, respectively). In Study 2, improvements in mean TPI score were statistically significantly greater with the 67% NaHCO3 dentifrice compared with both 0% NaHCO3 dentifrices (p < 0.0001 for both comparisons). All dentifrices were generally well tolerated. A single timed brushing with commercially available dentifrices containing 67% or 45% NaHCO3 exerted a significantly greater effect on

  14. Performance of Universal Adhesive in Primary Molars After Selective Removal of Carious Tissue: An 18-Month Randomized Clinical Trial.

    Science.gov (United States)

    Lenzi, Tathiane Larissa; Pires, Carine Weber; Soares, Fabio Zovico Maxnuck; Raggio, Daniela Prócida; Ardenghi, Thiago Machado; de Oliveira Rocha, Rachel

    2017-09-15

    To evaluate the 18-month clinical performance of a universal adhesive, applied under different adhesion strategies, after selective carious tissue removal in primary molars. Forty-four subjects (five to 10 years old) contributed with 90 primary molars presenting moderately deep dentin carious lesions on occlusal or occluso-proximal surfaces, which were randomly assigned following either self-etch or etch-and-rinse protocol of Scotchbond Universal Adhesive (3M ESPE). Resin composite was incrementally inserted for all restorations. Restorations were evaluated at one, six, 12, and 18 months using the modified United States Public Health Service criteria. Survival estimates for restorations' longevity were evaluated using the Kaplan-Meier method. Multivariate Cox regression analysis with shared frailty to assess the factors associated with failures (Padhesion strategy did not influence the restorations' longevity (P=0.06; 72.2 percent and 89.7 percent with etch-and-rinse and self-etch mode, respectively). Self-etch and etch-and-rinse strategies did not influence the clinical behavior of universal adhesive used in primary molars after selective carious tissue removal; although there was a tendency for better outcome of the self-etch strategy.

  15. Passive Noise Filtering by Cellular Compartmentalization.

    Science.gov (United States)

    Stoeger, Thomas; Battich, Nico; Pelkmans, Lucas

    2016-03-10

    Chemical reactions contain an inherent element of randomness, which presents itself as noise that interferes with cellular processes and communication. Here we discuss the ability of the spatial partitioning of molecular systems to filter and, thus, remove noise, while preserving regulated and predictable differences between single living cells. In contrast to active noise filtering by network motifs, cellular compartmentalization is highly effective and easily scales to numerous systems without requiring a substantial usage of cellular energy. We will use passive noise filtering by the eukaryotic cell nucleus as an example of how this increases predictability of transcriptional output, with possible implications for the evolution of complex multicellularity. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. 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.

  17. Questioning the wisdom of tubeless percutaneous nephrolithotomy (PCNL): a prospective randomized controlled study of early tube removal vs tubeless PCNL.

    Science.gov (United States)

    Mishra, Shashikant; Sabnis, Ravindra B; Kurien, Abraham; Ganpule, Arvind; Muthu, Veeramani; Desai, Mahesh

    2010-10-01

    To establish the efficacy of early removal of a nephrostomy tube after percutaneous nephrolithotomy (PCNL), to challenge the wisdom of tubeless PCNL, as we hypothesized that it would result in a shorter hospital stay, comparable benefit and safety, while maintaining the option of check nephroscopy ensuring far superior stone clearance. In all, 22 patients were prospectively randomized equally into two groups, group 1 (early nephrostomy removal) or group 2 (tubeless) during a 1-month study period. Inclusion criteria for the study were: a simple stone of Foley catheter were used, while in group 2 only a 6 F retrograde ureteric catheter and Foley catheter were placed at the end of the procedure. Computed tomography (CT) with no contrast medium was done on the first morning after surgery before removing all catheters/tubes, and patients discharged subsequently. The variables assessed were stone clearance, hospital stay, analgesic requirement, postoperative complications and auxiliary procedures. The mean (SD) stone bulk was similar between the groups, at 2737 (946.9) and 2934.2 (2090.7) µL, respectively. Despite an on-table complete clearance, clearance assessed by CT was nine of 11 vs eight of 11 in groups 1 and 2, respectively. CT showed a 6 mm stone in one patient in group 1, while the remaining patients had stones of haematuria in none vs three (P= 0.21), urinoma none vs one, and fever in two vs one, respectively; one patient in group 1 required a check nephroscopy for a residual fragment. Overall clearance including re-treatment was 10/11 vs eight of 11 (P= 0.009), respectively. Early tube removal after PCNL results in an equivalent analgesic requirement, decrease in haemoglobin and hospital stay as tubeless PCNL. It has a significantly lower incidence of early haematuria, better clearance rates and preserves the option of check nephroscopy. It can be considered as an accepted standard of care, with the preserved advantages of tubeless PCNL. © 2010 THE AUTHORS

  18. Microbiological analysis after complete or partial removal of carious dentin using two different techniques in primary teeth: A randomized clinical trial

    Science.gov (United States)

    Singhal, Deepak Kumar; Acharya, Shashidhar; Thakur, Arun Singh

    2016-01-01

    Background: The management of deep carious lesions can be done by various techniques but residual caries dilemma still persists and bacterial reduction in cavities treated by either partial or complete caries removal techniques is debatable. So the objective of the present randomized clinical trial was to compare microbial counts in cavities submitted to complete caries removal and partial caries removal using either hand instruments or burs before and after 3 weeks of restoration. Materials and Methods: Primary molars with acute carious lesions in inner half of dentine and vital pulp were randomly divided into three groups of 14 each: Group A: Partial caries removal using hand instruments atraumatic restorative treatment (ART) only; Group B: Partial caries removal using bur; Group C: Complete caries removal using bur and caries detector dye. Dentine sample obtained after caries removal and 3 weeks after restoration, were subjected to microbial culture and counting (colony-forming units [CFU]/mg of dentine) for total viable bacterial count, Streptococcus spp., mutans streptococci, Lactobacillus spp. Results: Three techniques of caries removal showed significant (P < 0.05) reduction in all microorganisms studied after 3 weeks of evaluation, but there was no statistically significant difference in percentage reduction of microbial count among three groups. Conclusion: Results suggest the use of partial caries removal in a single session as compared to complete caries removal as a part of treatment of deep lesions in deciduous teeth in order to reduce the risk of pulp exposure. Partial caries removal using ART can be preferred for community settings as public health procedure for caries management. PMID:26962313

  19. A randomized trial of early versus delayed mediastinal drain removal after cardiac surgery using silastic and conventional tubes

    Science.gov (United States)

    Moss, Emmanuel; Miller, Corey S.; Jensen, Henrik; Basmadjian, Arsène; Bouchard, Denis; Carrier, Michel; Perrault, Louis P.; Cartier, Raymond; Pellerin, Michel; Demers, Philippe

    2013-01-01

    OBJECTIVES Mediastinal drainage following cardiac surgery with traditional large-bore plastic tubes can be painful and cumbersome. This study was designed to determine whether prolonged drainage (5 days) with a silastic tube decreased the incidence of significant pericardial effusion and tamponade following aortic or valvular surgery. METHODS One hundred and fifty patients undergoing valvular or aortic surgery in a tertiary cardiac surgery institution were randomized to receive a conventional mediastinal tube plus a silastic Blake drain (n = 75), or two conventional tubes (n = 75). Conventional drains were removed on postoperative day (POD) 1, while Blake drains were removed on POD 5. The primary end-point was the combined incidence of significant pericardial effusion (≥15 mm) or tamponade through POD 5. Secondary end-points included total mediastinal drainage, postoperative atrial fibrillation (AF) and pain. RESULTS Analysis was performed for 67 patients in the Blake group and 73 in the conventional group. There was no difference between the two groups in the combined end-point of significant effusion or tamponade (7.4 vs 8.3%, P = 0.74), or in the incidence of AF (47 vs 46%, P = 0.89). Mean 24-h drainage was greater in the Blake group than in the conventional group (749 ± 444 ml vs 645 ± 618 ml, P tubes is safe and does not increase postoperative pain. There was no difference between the Blake and conventional drains with regard to significant pericardial effusion or tamponade in this cohort; however, this conclusion is limited by the low overall incidence of the primary outcome in this cohort. PMID:23575759

  20. Quantized dissipation and random telegraph voltage noise in epitaxial BiSrCaCuO thin films

    International Nuclear Information System (INIS)

    Jung, G.; Savo, B.; Vecchione, A.

    1993-01-01

    In this paper we report on the observation of correlated multiple-voltage RTN switching in high quality epitaxial BiSrCaCuO thin film. We ascribe the correlated noise to the quantization of flux flow dissipation in the film. (orig.)

  1. Postoperative socket irrigation with drinking tap water reduces the risk of inflammatory complications following surgical removal of third molars: a multicenter randomized trial

    NARCIS (Netherlands)

    Ghaeminia, H.; Hoppenreijs, T.J.; Xi, T.; Fennis, J.P.; Maal, T.J.J.; Berge, S.J.; Meijer, G.J.

    2017-01-01

    OBJECTIVES: The primary aim of the present study was to evaluate the effectiveness of postoperative irrigation of the socket with drinking tap water on inflammatory complications following lower third molar removal. MATERIAL AND METHODS: A multicenter randomized controlled trial was carried out from

  2. 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.

  3. Eliminating thermal violin spikes from LIGO noise

    International Nuclear Information System (INIS)

    Santamore, D. H.; Levin, Yuri

    2001-01-01

    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 ∼2 x 10 -13 cm/Hz. This sensitivity is two orders of magnitude greater than that of currently available sensors

  4. Musical noise reduction using an adaptive filter

    Science.gov (United States)

    Hanada, Takeshi; Murakami, Takahiro; Ishida, Yoshihisa; Hoya, Tetsuya

    2003-10-01

    This paper presents a method for reducing a particular noise (musical noise). The musical noise is artificially produced by Spectral Subtraction (SS), which is one of the most conventional methods for speech enhancement. The musical noise is the tin-like sound and annoying in human auditory. We know that the duration of the musical noise is considerably short in comparison with that of speech, and that the frequency components of the musical noise are random and isolated. In the ordinary SS-based methods, the musical noise is removed by the post-processing. However, the output of the ordinary post-processing is delayed since the post-processing uses the succeeding frames. In order to improve this problem, we propose a novel method using an adaptive filter. In the proposed system, the observed noisy signal is used as the input signal to the adaptive filter and the output of SS is used as the reference signal. In this paper we exploit the normalized LMS (Least Mean Square) algorithm for the adaptive filter. Simulation results show that the proposed method has improved the intelligibility of the enhanced speech in comparison with the conventional method.

  5. Active Noise Control for Dishwasher noise

    Science.gov (United States)

    Lee, Nokhaeng; Park, Youngjin

    2016-09-01

    The dishwasher is a useful home appliance and continually used for automatically washing dishes. It's commonly placed in the kitchen with built-in style for practicality and better use of space. In this environment, people are easily exposed to dishwasher noise, so it is an important issue for the consumers, especially for the people living in open and narrow space. Recently, the sound power levels of the noise are about 40 - 50 dBA. It could be achieved by removal of noise sources and passive means of insulating acoustical path. For more reduction, such a quiet mode with the lower speed of cycle has been introduced, but this deteriorates the washing capacity. Under this background, we propose active noise control for dishwasher noise. It is observed that the noise is propagating mainly from the lower part of the front side. Control speakers are placed in the part for the collocation. Observation part of estimating sound field distribution and control part of generating the anti-noise are designed for active noise control. Simulation result shows proposed active noise control scheme could have a potential application for dishwasher noise reduction.

  6. Noise Reduction for Nonlinear Nonstationary Time Series Data using Averaging Intrinsic Mode Function

    Directory of Open Access Journals (Sweden)

    Christofer Toumazou

    2013-07-01

    Full Text Available A novel noise filtering algorithm based on averaging Intrinsic Mode Function (aIMF, which is a derivation of Empirical Mode Decomposition (EMD, is proposed to remove white-Gaussian noise of foreign currency exchange rates that are nonlinear nonstationary times series signals. Noise patterns with different amplitudes and frequencies were randomly mixed into the five exchange rates. A number of filters, namely; Extended Kalman Filter (EKF, Wavelet Transform (WT, Particle Filter (PF and the averaging Intrinsic Mode Function (aIMF algorithm were used to compare filtering and smoothing performance. The aIMF algorithm demonstrated high noise reduction among the performance of these filters.

  7. Removing the Influence of Shimmer in the Calculation of Harmonics-To-Noise Ratios Using Ensemble-Averages in Voice Signals

    OpenAIRE

    Carlos Ferrer; Eduardo González; María E. Hernández-Díaz; Diana Torres; Anesto del Toro

    2009-01-01

    Harmonics-to-noise ratios (HNRs) are affected by general aperiodicity in voiced speech signals. To specifically reflect a signal-to-additive-noise ratio, the measurement should be insensitive to other periodicity perturbations, like jitter, shimmer, and waveform variability. The ensemble averaging technique is a time-domain method which has been gradually refined in terms of its sensitivity to jitter and waveform variability and required number of pulses. In this paper, shimmer is introduced ...

  8. Energy-Based Wavelet De-Noising of Hydrologic Time Series

    Science.gov (United States)

    Sang, Yan-Fang; Liu, Changming; Wang, Zhonggen; Wen, Jun; Shang, Lunyu

    2014-01-01

    De-noising is a substantial issue in hydrologic time series analysis, but it is a difficult task due to the defect of methods. In this paper an energy-based wavelet de-noising method was proposed. It is to remove noise by comparing energy distribution of series with the background energy distribution, which is established from Monte-Carlo test. Differing from wavelet threshold de-noising (WTD) method with the basis of wavelet coefficient thresholding, the proposed method is based on energy distribution of series. It can distinguish noise from deterministic components in series, and uncertainty of de-noising result can be quantitatively estimated using proper confidence interval, but WTD method cannot do this. Analysis of both synthetic and observed series verified the comparable power of the proposed method and WTD, but de-noising process by the former is more easily operable. The results also indicate the influences of three key factors (wavelet choice, decomposition level choice and noise content) on wavelet de-noising. Wavelet should be carefully chosen when using the proposed method. The suitable decomposition level for wavelet de-noising should correspond to series' deterministic sub-signal which has the smallest temporal scale. If too much noise is included in a series, accurate de-noising result cannot be obtained by the proposed method or WTD, but the series would show pure random but not autocorrelation characters, so de-noising is no longer needed. PMID:25360533

  9. Approximations to camera sensor noise

    Science.gov (United States)

    Jin, Xiaodan; Hirakawa, Keigo

    2013-02-01

    Noise is present in all image sensor data. Poisson distribution is said to model the stochastic nature of the photon arrival process, while it is common to approximate readout/thermal noise by additive white Gaussian noise (AWGN). Other sources of signal-dependent noise such as Fano and quantization also contribute to the overall noise profile. Question remains, however, about how best to model the combined sensor noise. Though additive Gaussian noise with signal-dependent noise variance (SD-AWGN) and Poisson corruption are two widely used models to approximate the actual sensor noise distribution, the justification given to these types of models are based on limited evidence. The goal of this paper is to provide a more comprehensive characterization of random noise. We concluded by presenting concrete evidence that Poisson model is a better approximation to real camera model than SD-AWGN. We suggest further modification to Poisson that may improve the noise model.

  10. Random noise attenuation of non-uniformly sampled 3D seismic data along two spatial coordinates using non-equispaced curvelet transform

    Science.gov (United States)

    Zhang, Hua; Yang, Hui; Li, Hongxing; Huang, Guangnan; Ding, Zheyi

    2018-04-01

    The attenuation of random noise is important for improving the signal to noise ratio (SNR). However, the precondition for most conventional denoising methods is that the noisy data must be sampled on a uniform grid, making the conventional methods unsuitable for non-uniformly sampled data. In this paper, a denoising method capable of regularizing the noisy data from a non-uniform grid to a specified uniform grid is proposed. Firstly, the denoising method is performed for every time slice extracted from the 3D noisy data along the source and receiver directions, then the 2D non-equispaced fast Fourier transform (NFFT) is introduced in the conventional fast discrete curvelet transform (FDCT). The non-equispaced fast discrete curvelet transform (NFDCT) can be achieved based on the regularized inversion of an operator that links the uniformly sampled curvelet coefficients to the non-uniformly sampled noisy data. The uniform curvelet coefficients can be calculated by using the inversion algorithm of the spectral projected-gradient for ℓ1-norm problems. Then local threshold factors are chosen for the uniform curvelet coefficients for each decomposition scale, and effective curvelet coefficients are obtained respectively for each scale. Finally, the conventional inverse FDCT is applied to the effective curvelet coefficients. This completes the proposed 3D denoising method using the non-equispaced curvelet transform in the source-receiver domain. The examples for synthetic data and real data reveal the effectiveness of the proposed approach in applications to noise attenuation for non-uniformly sampled data compared with the conventional FDCT method and wavelet transformation.

  11. 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

  12. Comparison of toxin removal outcomes in online hemodiafiltration and intra-dialytic exercise in high-flux hemodialysis: A prospective randomized open-label clinical study protocol

    Directory of Open Access Journals (Sweden)

    Maheshwari Vaibhav

    2012-11-01

    Full Text Available Abstract Background Maintenance hemodialysis (HD patients universally suffer from excess toxin load. Hemodiafiltration (HDF has shown its potential in better removal of small as well as large sized toxins, but its efficacy is restricted by inter-compartmental clearance. Intra-dialytic exercise on the other hand is also found to be effective for removal of toxins; the augmented removal is apparently obtained by better perfusion of skeletal muscles and decreased inter-compartmental resistance. The aim of this trial is to compare the toxin removal outcome associated with intra-dialytic exercise in HD and with post-dilution HDF. Methods/design The main hypothesis of this study is that intra-dialytic exercise enhances toxin removal by decreasing the inter-compartmental resistance, a major impediment for toxin removal. To compare the HDF and HD with exercise, the toxin rebound for urea, creatinine, phosphate, and β2-microglobulin will be calculated after 2 hours of dialysis. Spent dialysate will also be collected to calculate the removed toxin mass. To quantify the decrease in inter-compartmental resistance, the recently developed regional blood flow model will be employed. The study will be single center, randomized, self-control, open-label prospective clinical research where 15 study subjects will undergo three dialysis protocols (a high flux HD, (b post-dilution HDF, (c high flux HD with exercise. Multiple blood samples during each study session will be collected to estimate the unknown model parameters. Discussion This will be the first study to investigate the exercise induced physiological change(s responsible for enhanced toxin removal, and compare the toxin removal outcome both for small and middle sized toxins in HD with exercise and HDF. Successful completion of this clinical research will give important insights into exercise effect on factors responsible for enhanced toxin removal. The knowledge will give confidence for implementing

  13. Comparison of bandage contact lens removal on the fourth versus seventh postoperative day after photorefractive keratectomy: A randomized clinical trial

    Directory of Open Access Journals (Sweden)

    Mehrdad Mohammadpour

    2017-06-01

    Conclusion: Following PRK surgery, BCL removal on the seventh postoperative day yields faster visual rehabilitation and lower rate of postoperative complications with no increase in eye pain, discomfort or infection.

  14. A randomized controlled trial of self-perceived pain, discomfort, and impairment of jaw function in children undergoing orthodontic treatment with fixed or removable appliances.

    Science.gov (United States)

    Wiedel, Anna-Paulina; Bondemark, Lars

    2016-03-01

    To compare patients' perceptions of fixed and removable appliance therapy for correction of anterior crossbite in the mixed dentition, with special reference to perceived pain, discomfort, and impairment of jaw function. Sixty-two patients with anterior crossbite and functional shift were recruited consecutively and randomized for treatment with fixed appliances (brackets and archwires) or removable appliances (acrylic plates and protruding springs). A questionnaire, previously found to be valid and reliable, was used for evaluation at the following time points: before appliance insertion, on the evening of the day of insertion, every day/evening for 7 days after insertion, and at the first and second scheduled appointments (after 4 and 8 weeks, respectively). Pain and discomfort intensity were higher for the first 3 days for the fixed appliance. Pain and discomfort scores overall peaked on day 2. Adverse effects on school and leisure activities were reported more frequently in the removable than in the fixed appliance group. The fixed appliance group reported more difficulty eating different kinds of hard and soft food, while the removable appliance group experienced more speech difficulties. No significant intergroup difference was found for self-estimated disturbance of appearance between the appliances. The general levels of pain and discomfort were low to moderate in both groups. There were some statistically significant differences between the groups, but these were only minor and with minor clinical relevance. As both appliances were generally well accepted by the patients, either fixed or removable appliance therapy can be recommended.

  15. 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…

  16. Efficacy and Safety of Hair Removal with a Long-Pulsed Diode Laser Depending on the Spot Size: A Randomized, Evaluators-Blinded, Left-Right Study.

    Science.gov (United States)

    Jo, Seong Jin; Kim, Jin Yong; Ban, Juhee; Lee, Youngjoo; Kwon, Ohsang; Koh, Wooseok

    2015-10-01

    The efficacy of the long-pulsed diode laser (LPDL) in hair removal is determined with various physical parameters. Recently, LPDLs with a larger spot size are commercially available; however, the independent effect of spot size on hair removal has not been studied. This study aimed to compare the efficacy of the LPDL in hair removal depending on the spot size. A randomized, evaluators-blind, intrapatient comparison (left vs. right) trial was designed. Ten healthy Korean women received three hair removal treatment sessions on both armpits with the 805-nm LPDL and followed for 3 months. A 10×10 mm handpiece (D1) or a 10×30 mm handpiece (D3) was randomly assigned to the right or left axilla. The fluence, pulse duration, and epidermal cooling temperature were identical for both armpits. Hair clearance was quantified with high-resolution photos taken at each visit. Postprocedural pain was quantified on a visual analogue scale. Adverse events were evaluated by physical examination and the patients' self-report. The mean hair clearance at 3 months after three treatment sessions was 38.7% and 50.1% on the armpits treated with D1 and D3, respectively (p=0.028). Procedural pain was significantly greater in the side treated with D3 (p=0.009). Serious adverse events were not observed. Given that the pulse duration, fluence, and epidermal cooling were identical, the 805-nm LPDL at the three times larger spot size showed an efficacy improvement of 29.5% in axillary hair removal without serious adverse events.

  17. Noise/spike detection in phonocardiogram signal as a cyclic random process with non-stationary period interval.

    Science.gov (United States)

    Naseri, H; Homaeinezhad, M R; Pourkhajeh, H

    2013-09-01

    The major aim of this study is to describe a unified procedure for detecting noisy segments and spikes in transduced signals with a cyclic but non-stationary periodic nature. According to this procedure, the cycles of the signal (onset and offset locations) are detected. Then, the cycles are clustered into a finite number of groups based on appropriate geometrical- and frequency-based time series. Next, the median template of each time series of each cluster is calculated. Afterwards, a correlation-based technique is devised for making a comparison between a test cycle feature and the associated time series of each cluster. Finally, by applying a suitably chosen threshold for the calculated correlation values, a segment is prescribed to be either clean or noisy. As a key merit of this research, the procedure can introduce a decision support for choosing accurately orthogonal-expansion-based filtering or to remove noisy segments. In this paper, the application procedure of the proposed method is comprehensively described by applying it to phonocardiogram (PCG) signals for finding noisy cycles. The database consists of 126 records from several patients of a domestic research station acquired by a 3M Littmann(®) 3200, 4KHz sampling frequency electronic stethoscope. By implementing the noisy segments detection algorithm with this database, a sensitivity of Se=91.41% and a positive predictive value, PPV=92.86% were obtained based on physicians assessments. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Removing the Influence of Shimmer in the Calculation of Harmonics-To-Noise Ratios Using Ensemble-Averages in Voice Signals

    Directory of Open Access Journals (Sweden)

    Carlos Ferrer

    2009-01-01

    Full Text Available Harmonics-to-noise ratios (HNRs are affected by general aperiodicity in voiced speech signals. To specifically reflect a signal-to-additive-noise ratio, the measurement should be insensitive to other periodicity perturbations, like jitter, shimmer, and waveform variability. The ensemble averaging technique is a time-domain method which has been gradually refined in terms of its sensitivity to jitter and waveform variability and required number of pulses. In this paper, shimmer is introduced in the model of the ensemble average, and a formula is derived which allows the reduction of shimmer effects in HNR calculation. The validity of the technique is evaluated using synthetically shimmered signals, and the prerequisites (glottal pulse positions and amplitudes are obtained by means of fully automated methods. The results demonstrate the feasibility and usefulness of the correction.

  19. 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.

  20. A split-mouth randomized clinical trial to evaluate the performance of piezosurgery compared with traditional technique in lower wisdom tooth removal.

    Science.gov (United States)

    Mantovani, Edoardo; Arduino, Paolo Giacomo; Schierano, Gianmario; Ferrero, Luca; Gallesio, Giorgia; Mozzati, Marco; Russo, Andrea; Scully, Crispian; Carossa, Stefano

    2014-10-01

    The surgical removal of mandibular third molars is frequently accompanied by significant postsurgical sequelae, and different protocols have been described to decrease such adverse events. The aim of this study was to investigate the performance of piezosurgery compared with traditional rotating instruments during mandibular third molar removal. A single-center, randomized, split-mouth study was performed using a consecutive series of unrelated healthy patients attending the Oral Surgery Unit of the University of Turin for surgical removal of bilateral mandibular third molar teeth. Each patient was treated, at the same appointment, using bur removal on 1 side of the mandible and a piezoelectric device on the contralateral side. The primary outcomes reported were postoperative pain, objective orofacial swelling, and surgical duration; secondary outcomes were gender, age, and possible adverse events. Analysis of variance or paired t test was used as appropriate to test any significant differences at baseline according to each treatment subgroup, and categorical variables were analyzed by χ(2) test. The study sample consisted of 100 otherwise healthy patients. The mean pain evaluation reported by patients who underwent surgery with piezosurgery was significantly lower than that reported after bur (conventional) removal, reaching statistical difference after 4 days (P = .043). The clinical value of orofacial swelling at day 7, normalized to baseline, was lower in the piezosurgery group (P piezosurgery group (P piezosurgery for lower third molar tooth removal. This study also compared surgeons with different degrees of experience. It is evident that using a piezoelectric device can enhance the patient experience and decrease postoperative pain and swelling. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  1. Detector point of view of reactor internal vibrations under Gaussian coloured random forces - the problem of fitting neutron noise experimental data

    International Nuclear Information System (INIS)

    Arnal, R.S.; Martin, G.V.; Gonzalez, J.L.M.-C.

    1988-01-01

    This paper studies the local vibrations of reactor components driven by Gaussian coloured and white forces, when nonlinear vibrations arise. We study also the important problem of noise sources, modelization and the noise propagation through the neutron field using the discrete ordinates transport theory. Finally, we study the effect of the neutron field upon the PSD (power spectral density) of the noise source and we analyse the problem of fitting neutron noise experimental data to perform pattern recognition analysis. (author)

  2. Randomized, double-blind, placebo-controlled trial to test the efficacy of nitradine tablets in maxillary removable orthodontic appliance patients.

    Science.gov (United States)

    Vento-Zahra, Ethel; De Wever, Bart; Decelis, Stephen; Mallia, Kenneth; Camilleri, Simon

    2011-01-01

    to evaluate the efficiency of NitrAdine (MSI Laboratories) tablets in the reduction of oral Candida levels, biofilm formation, and appliance odor in maxillary removable orthodontic appliance wearers. seventy children between 11 and 15 years of age undergoing maxillary removable appliance treatment were assigned via a double-blind randomized method to the experimental or placebo arm of the study. One milliliter of unstimulated saliva was collected at the beginning of the experiment and 6 weeks later after treatment of the maxillary removable appliance with NitrAdine tablets. Samples were cultured on chromogenic Candida agar, and the number of colony-forming units per mL of saliva (CFU mL-1) was determined. there was no significant difference in salivary Candida levels before or after treatment with NitrAdine tablets. There was a significant drop in plaque accumulation on the appliance and a significant amelioration in appliance odor. There was a small, nonsignificant drop in individuals exhibiting counts of 400 CFU mL-1 or more in the experimental group and a nonsignificant increase in the number of new species in the placebo group. NitrAdine tablets are effective in reducing plaque accumulation and appliance odor during maxillary removable appliance treatment. Further in vivo studies are required to determine the efficacy and exact protocol for NitrAdine tablets in appliance disinfection.

  3. One-step partial or complete caries removal and bonding with antibacterial or traditional self-etch adhesives: study protocol for a randomized controlled trial.

    Science.gov (United States)

    Villat, Cyril; Attal, Jean-Pierre; Brulat, Nathalie; Decup, Franck; Doméjean, Sophie; Dursun, Elisabeth; Fron-Chabouis, Hélène; Jacquot, Bruno; Muller Bolla, Michèle; Plasse-Pradelle, Nelly; Roche, Laurent; Maucort-Boulch, Delphine; Nony, Patrice; Gritsch, Kerstin; Millet, Pierre; Gueyffier, François; Grosgogeat, Brigitte

    2016-08-15

    Current concepts in conservative dentistry advocate minimally invasive dentistry and pulp vitality preservation. Moreover, complete removal of carious dentin in deep carious lesions often leads to pulp exposure and root canal treatment, despite the absence of irreversible pulp inflammation. For years, partial caries removal has been performed on primary teeth, but little evidence supports its effectiveness for permanent teeth. Furthermore, the recent development of new antibacterial adhesive systems could be interesting in the treatment of such lesions. The objectives of this study are to compare the effectiveness of partial versus complete carious dentin removal in deep lesions (primary objective) and the use of an antibacterial versus a traditional two-step self-etch adhesive system (main secondary objective). The DEep CAries Treatment (DECAT) study protocol is a multicenter, randomized, controlled superiority trial comparing partial versus complete caries removal followed by adhesive restoration. The minimum sample size required is 464 patients. Two successive randomizations will be performed (allocation ratio 1:1): the first for the type of excavation (partial versus complete) and the second (if no root canal treatment is required) for the type of adhesive (antibacterial versus traditional). For the two objectives, the outcome is the success of the treatment after 1 year, measured according to a composite outcome of five FDI criteria: material fracture and retention, marginal adaptation, radiographic examination (including apical pathologies), postoperative sensitivity and tooth vitality, and carious lesion recurrence. The study will investigate the interest of a conservative approach for the management of deep carious lesions in terms of dentin excavation and bioactive adhesive systems. The results may help practitioners achieve the most efficient restorative procedure to maintain pulp vitality and increase the restoration longevity. Clinical

  4. The evaluation of off-loading using a new removable oRTHOsis in DIABetic foot (ORTHODIAB) randomized controlled trial: study design and rational.

    Science.gov (United States)

    Mohammedi, Kamel; Potier, Louis; François, Maud; Dardari, Dured; Feron, Marilyne; Nobecourt-Dupuy, Estelle; Dolz, Manuel; Ducloux, Roxane; Chibani, Abdelkader; Eveno, Dominique-François; Crea Avila, Teresa; Sultan, Ariane; Baillet-Blanco, Laurence; Rigalleau, Vincent; Velho, Gilberto; Tubach, Florence; Roussel, Ronan; Dupré, Jean-Claude; Malgrange, Dominique; Marre, Michel

    2016-01-01

    Off-loading is essential for diabetic foot management, but remains understudied. The evaluation of Off-loading using a new removable oRTHOsis in DIABetic foot (ORTHODIAB) trial aims to evaluate the efficacy of a new removable device "Orthèse Diabète" in the healing of diabetic foot. ORTHODIAB is a French multi-centre randomized, open label trial, with a blinded end points evaluation by an adjudication committee according to the Prospective Randomized Open Blinded End-point. Main endpoints are adjudicated based on the analysis of diabetic foot photographs. Orthèse Diabète is a new removable off-loading orthosis (PROTEOR, France) allowing innovative functions including real-time evaluation of off-loading and estimation of patients' adherence. Diabetic patients with neuropathic plantar ulcer or amputation wounds (toes or transmetatarsal) are assigned to one of 2 parallel-groups: Orthèse Diabète or control group (any removable device) according to a central computer-based randomization. Study visits are scheduled for 6 months (days D7 and D14, and months M1, M2, M3, and M6). The primary endpoint is the proportion of patients whose principal ulcer is healed at M3. Secondary endpoints are: the proportion of patients whose principal ulcer is healed at M1, M2 and M6; the proportion of patients whose initial ulcers are all healed at M1, M2, M3, and M6; principal ulcer area reduction; time-related ulcer-free survival; development of new ulcers; new lower-extremity amputation; infectious complications; off-loading adherence; and patient satisfaction. The study protocol was approved by the French National Agency for Medicines and Health Products Safety, and by the ethics committee of Saint-Louis Hospital (Paris). Comprehensive study information including a Patient Information Sheet has been provided to each patient who must give written informed consent before enrolment. Monitoring, data management, and statistical analyses are providing by UMANIS Life Science (Paris

  5. 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.

  6. New ways of removing cyclic borehole noise from low- and high-resolution LWD images and its impact on image interpretation

    Energy Technology Data Exchange (ETDEWEB)

    Lalchan, C.; Wiggins, C.; Moriyama, C. [Trican Well Service (Canada)

    2011-07-01

    With the depletion of conventional oil reservoirs and increasing energy demand, the exploitation of unconventional resources is underway. Until now, the use of emulsified acids, which dissolve organic and inorganic deposits and strip off layered scales, has been restricted to conventional reservoirs, but it could also be used for thermal heavy oil reservoirs. The aim of this paper is to determine the appropriate acid blend for deposit and scale removal in thermal heavy oil reservoirs. Acid formulations were tested under 170 degrees Celsius and sensitivity testing was performed to find the optimal concentration. Results showed that a 5% or 10% acid acetic, emulsified in a 4:1 ratio with a modified wax and asphaltenes solvent blend, is the optimal acid formulation for removal of scales and organic deposits. This paper demonstrated that emulsified acids can be used to stimulate water injection and production in thermal heavy oil reservoirs and provided the optimum acid formulation.

  7. Noise Enhanced Stability

    International Nuclear Information System (INIS)

    Spagnolo, B.; Agudov, N.V.; Dubkov, A.A.

    2004-01-01

    The noise can stabilize a fluctuating or a periodically driven metastable state in such a way that the system remains in this state for a longer time than in the absence of white noise. This is the noise enhanced stability phenomenon, observed experimentally and numerically in different physical systems. After shortly reviewing all the physical systems where the phenomenon was observed, the theoretical approaches used to explain the effect are presented. Specifically the conditions to observe the effect in systems: (a) with periodical driving force, and (b) with random dichotomous driving force, are discussed. In case (b) we review the analytical results concerning the mean first passage time and the nonlinear relaxation time as a function of the white noise intensity, the parameters of the potential barrier, and of the dichotomous noise. (author)

  8. Mapping of Natural Radionuclides using Noise Adjusted Singular Value Decomposition, NASVD

    DEFF Research Database (Denmark)

    Aage, Helle Karina

    2006-01-01

    Mapping of natural radionuclides from airborne gamma spectrometry suffer from random ”noise” in the spectra due to short measurement times. This is partly compensated for by using large volume detectors to improve the counting statistics. One method of further improving the quality of the measured...... spectra is to remove from the spectra a large fraction of this random noise using a special variant of Singular Value Decomposition: Noise Adjusted Singular Value Decomposition. In 1997-1999 the natural radionuclides on the Danish Island of Bornholm were mapped using a combination of the standard 3...

  9. Impact of tamsulosin on urinary retention following early catheter removal after robot-assisted laparoscopic radical prostatectomy: a prospective randomized controlled trial.

    Science.gov (United States)

    Jeong, In Gab; You, Dalsan; Yoon, Jong Hyun; Hong, Sungwoo; Lim, Ju Hyun; Hong, Jun Hyuk; Choo, Myung-Soo; Ahn, Hanjong; Kim, Choung-Soo

    2014-02-01

    To examine the impact of tamsulosin on the rate of acute urinary retention following early catheter removal after robot-assisted laparoscopic radical prostatectomy. A total of 236 patients who underwent robot-assisted laparoscopic radical prostatectomy for prostate cancer carried out by a single surgeon were enrolled in this randomized study. Patients were randomly divided into two groups: treatment with tamsulosin (0.4 mg) from 1 day before to 14 days after surgery (tamsulosin group), or no tamsulosin treatment (control group). The urethral catheter was removed on the fifth postoperative day. The primary end-point was the acute urinary retention rate. Changes in each domain of the International Continence Society male short-form questionnaire and uroflowmetry parameters were secondary end-points. The primary end-point was assessed in 218 patients (92.4%; n = 109 in each group). It was not assessed in 18 patients because of cystographic leak from the vesicourethral anastomosis. The acute urinary retention rate was lower in the tamsulosin group (7.3%) than in the control group (17.4%, P = 0.018). Multivariate logistic regression analysis identified tamsulosin treatment and the operative experience of the surgeon as independent risk factors for acute urinary retention. Tamsulosin-treated patients had a 0.30-fold lower risk of developing acute urinary retention compared with control patients (95% confidence interval 0.12-0.76; P = 0.011). None of the International Continence Society male questionnaire domain scores showed significant changes between the groups. Perioperative treatment with tamsulosin in patients undergoing robot-assisted laparoscopic radical prostatectomy reduces the rate of acute urinary retention after early catheter removal, without aggravating urinary incontinence. © 2013 The Japanese Urological Association.

  10. Maximizing noise energy for noise-masking studies.

    Science.gov (United States)

    Jules Étienne, Cédric; Arleo, Angelo; Allard, Rémy

    2017-08-01

    Noise-masking experiments are widely used to investigate visual functions. To be useful, noise generally needs to be strong enough to noticeably impair performance, but under some conditions, noise does not impair performance even when its contrast approaches the maximal displayable limit of 100 %. To extend the usefulness of noise-masking paradigms over a wider range of conditions, the present study developed a noise with great masking strength. There are two typical ways of increasing masking strength without exceeding the limited contrast range: use binary noise instead of Gaussian noise or filter out frequencies that are not relevant to the task (i.e., which can be removed without affecting performance). The present study combined these two approaches to further increase masking strength. We show that binarizing the noise after the filtering process substantially increases the energy at frequencies within the pass-band of the filter given equated total contrast ranges. A validation experiment showed that similar performances were obtained using binarized-filtered noise and filtered noise (given equated noise energy at the frequencies within the pass-band) suggesting that the binarization operation, which substantially reduced the contrast range, had no significant impact on performance. We conclude that binarized-filtered noise (and more generally, truncated-filtered noise) can substantially increase the energy of the noise at frequencies within the pass-band. Thus, given a limited contrast range, binarized-filtered noise can display higher energy levels than Gaussian noise and thereby widen the range of conditions over which noise-masking paradigms can be useful.

  11. A prospective randomized, controlled trial deems a drainage of 300 ml/day safe before removal of the last chest drain after video-assisted thoracoscopic surgery lobectomy.

    Science.gov (United States)

    Xie, Hong-Ya; Xu, Kai; Tang, Jin-Xing; Bian, Wen; Ma, Hai-Tao; Zhao, Jun; Ni, Bin

    2015-08-01

    To study the feasible and safe volume threshold for chest tube removal following video-assisted thoracoscopic surgical lobectomy. One hundred and sixty-eight consecutive patients (18 were excluded) who underwent video-assisted thoracoscopic surgery lobectomy or bilobectomy with two incisions between August 2012 and February 2014 were included. Eligible patients were randomized into three groups: Group A (chest tube was removed at a drainage volume of 150 ml/day or less. n = 49); Group B (chest tube was removed when the drainage volume was less than 300 ml/day. n = 50); Group C (chest tube was removed when the drainage volume was less than 450 ml/day. n = 51). The postoperative care of all patients was consistent. The time of extracting the drainage tube, postoperative hospital stay, postoperative visual analogue scale grades, dosage of analgesic, and the incidence of complications and thoracocentesis were measured. Group B and C had a much shorter drainage time and postoperative hospital stay than Group A (P 0.05). The mean dosage of pethidine hydrochloride was 248.9 ± 33.3 mg in Group B and 226.1 ± 32.7 mg in Group C (P > 0.05). The dosage of pethidine hydrochloride of Group A was significantly higher than that of Group B and C (P 0.05), Group A had a significantly higher total VAS score than Group B and C (P drains among the three groups (P > 0.05). A 300-ml/day volume threshold for chest tube removal after video-assisted thoracoscopic surgery lobectomy is feasible and safe, demonstating more advantages than the 150-ml/day volume threshold. However, a 450-ml/day volume threshold for chest tube removal may increase the risk of thoracentesis compared with the 300- and the 150-ml/day volume threshold. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  12. 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.

  13. A 7 ke-SD-FWC 1.2 e-RMS Temporal Random Noise 128×256 Time-Resolved CMOS Image Sensor With Two In-Pixel SDs for Biomedical Applications.

    Science.gov (United States)

    Seo, Min-Woong; Kawahito, Shoji

    2017-12-01

    A large full well capacity (FWC) for wide signal detection range and low temporal random noise for high sensitivity lock-in pixel CMOS image sensor (CIS) embedded with two in-pixel storage diodes (SDs) has been developed and presented in this paper. For fast charge transfer from photodiode to SDs, a lateral electric field charge modulator (LEFM) is used for the developed lock-in pixel. As a result, the time-resolved CIS achieves a very large SD-FWC of approximately 7ke-, low temporal random noise of 1.2e-rms at 20 fps with true correlated double sampling operation and fast intrinsic response less than 500 ps at 635 nm. The proposed imager has an effective pixel array of and a pixel size of . The sensor chip is fabricated by Dongbu HiTek 1P4M 0.11 CIS process.

  14. 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.

  15. Noise Pollution

    Science.gov (United States)

    ... Regulated by EPA EPA or a designated Federal agency regulates noise sources, such as rail and motor carriers, low noise emission products, construction equipment, transport equipment, trucks, motorcycles, and the labeling of hearing ...

  16. Magnetic field induced random pulse trains of magnetic and acoustic noises in martensitic single-crystal Ni2MnGa

    Science.gov (United States)

    Daróczi, Lajos; Piros, Eszter; Tóth, László Z.; Beke, Dezső L.

    2017-07-01

    Jerky magnetic and acoustic noises were evoked in a single variant martensitic Ni2MnGa single crystal (produced by uniaxial compression) by application of an external magnetic field along the hard magnetization direction. It is shown that after reaching the detwinning threshold, spontaneous reorientation of martensite variants (twins) leads not only to acoustic emission but magnetic two-directional noises as well. At small magnetic fields, below the above threshold, unidirectional magnetic emission is also observed and attributed to a Barkhausen-type noise due to magnetic domain wall motions during magnetization along the hard direction. After the above first run, in cycles of decreasing and increasing magnetic field, at low-field values, weak, unidirectional Barkhausen noise is detected and attributed to the discontinuous motion of domain walls during magnetization along the easy magnetization direction. The magnetic noise is also measured by constraining the sample in the same initial variant state along the hard direction and, after the unidirectional noise (as obtained also in the first run), a two-directional noise package is developed and it is attributed to domain rotations. From the statistical analysis of the above noises, the critical exponents, characterizing the power-law behavior, are calculated and compared with each other and with the literature data. Time correlations within the magnetic as well as acoustic signals lead to a common scaled power function (with β =-1.25 exponent) for both types of signals.

  17. Digital circuit for the introduction and later removal of dither from an analog signal

    Science.gov (United States)

    Borgen, Gary S.

    1994-05-01

    An electronics circuit is presented for accurately digitizing an analog audio or like data signal into a digital equivalent signal by introducing dither into the analog signal and then subsequently removing the dither from the digitized signal prior to its conversion to an analog signal which is a substantial replica of the incoming analog audio or like data signal. The electronics circuit of the present invention is characterized by a first pseudo-random number generator which generates digital random noise signals or dither for addition to the digital equivalent signal and a second pseudo-random number generator which generates subtractive digital random noise signals for the subsequent removal of dither from the digital equivalent signal prior its conversion to the analog replica signal.

  18. Community noise

    Science.gov (United States)

    Bragdon, C. R.

    Airport and community land use planning as they relate to airport noise reduction are discussed. Legislation, community relations, and the physiological effect of airport noise are considered. Noise at the Logan, Los Angeles, and Minneapolis/St. Paul airports is discussed.

  19. Use of onion extract, heparin, allantoin gel in prevention of scarring in chinese patients having laser removal of tattoos: a prospective randomized controlled trial.

    Science.gov (United States)

    Ho, Wai Sun; Ying, Shun Yuen; Chan, Pik Chu; Chan, Henry H

    2006-07-01

    With rapid advancement in cutaneous laser therapy, Q-switched lasers have become the standard treatment for tattoo removal. The longer wavelength Q-switched Nd:YAG laser is used when removing tattoos in darker skin patients to avoid scarring and permanent pigment changes. Nevertheless, the local experience revealed that nearly 25% of the Chinese patients developed scarring. Meanwhile, multiple clinical studies have shown that Contractubex gel (Merz Pharma, Frankfurt, Germany) was effective in the treatment and prevention of hypertrophic scars and keloids. To evaluate the efficacy of Contractubex gel in the prevention of scarring after laser removal of tattoos in Chinese patients. A total of 120 Chinese patients with 144 professional blue-black tattoos were recruited into the study. They were randomly assigned into the Contractubex group or the control group. All patients were treated with a QS 1,064-nm Nd:YAG laser using a 3-mm spot size, a 10-Hz repeat rate, a pulse duration of 6 nanoseconds, and fluences that ranged from 3.6 to 4.8 J/cm2 (mean fluence, 4.2 J/cm2). The treated areas were assessed 3 months after the last treatments for clinical clearance and complications. Fifty-two patients with 61 tattoos in the Contractubex group were able to achieve a mean clearing rate of 82.3+/-11.6%. There were 7 tattoos in 7 patients that developed scarring, 4 patients had permanent hypopigmentation, and 3 patients had transient hyperpigmentation. In contrast, 55 patients with 68 tattoos in the control group had a mean clearing rate of 80.4+/-11.3%. Among them, 16 tattoos in 14 patients developed scarring, 4 patients had permanent hypopigmentation, and 5 patients had transient hyperpigmentation. Although there was no significant difference in age, sex, fluence, treatment session, and clinical clearance between the two groups, the Contractubex group had a statistically significantly lower rate of scarring than the control group (ptattoos.

  20. Comparison of Piezosurgery and Conventional Rotary Instruments for Removal of Impacted Mandibular Third Molars: A Randomized Controlled Clinical and Radiographic Trial

    Science.gov (United States)

    Shokry, Mohamed; Aboelsaad, Nayer

    2016-01-01

    The purpose of this study was to test the effect of the surgical removal of impacted mandibular third molars using piezosurgery versus the conventional surgical technique on postoperative sequelae and bone healing. Material and Methods. This study was carried out as a randomized controlled clinical trial: split mouth design. Twenty patients with bilateral mandibular third molar mesioangular impaction class II position B indicated for surgical extraction were treated randomly using either the piezosurgery or the conventional bur technique on each site. Duration of the procedure, postoperative edema, trismus, pain, healing, and bone density and quantity were evaluated up to 6 months postoperatively. Results. Test and control sites were compared using paired t-test. There was statistical significance in reduction of pain and swelling in test sites, where the time of the procedure was statistically increased in test site. For bone quantity and quality, statistical difference was found where test site showed better results. Conclusion. Piezosurgery technique improves quality of patient's life in form of decrease of postoperative pain, trismus, and swelling. Furthermore, it enhances bone quality within the extraction socket and bone quantity along the distal aspect of the mandibular second molar. PMID:27597866

  1. Comparison of Piezosurgery and Conventional Rotary Instruments for Removal of Impacted Mandibular Third Molars: A Randomized Controlled Clinical and Radiographic Trial

    Directory of Open Access Journals (Sweden)

    Hani Arakji

    2016-01-01

    Full Text Available The purpose of this study was to test the effect of the surgical removal of impacted mandibular third molars using piezosurgery versus the conventional surgical technique on postoperative sequelae and bone healing. Material and Methods. This study was carried out as a randomized controlled clinical trial: split mouth design. Twenty patients with bilateral mandibular third molar mesioangular impaction class II position B indicated for surgical extraction were treated randomly using either the piezosurgery or the conventional bur technique on each site. Duration of the procedure, postoperative edema, trismus, pain, healing, and bone density and quantity were evaluated up to 6 months postoperatively. Results. Test and control sites were compared using paired t-test. There was statistical significance in reduction of pain and swelling in test sites, where the time of the procedure was statistically increased in test site. For bone quantity and quality, statistical difference was found where test site showed better results. Conclusion. Piezosurgery technique improves quality of patient’s life in form of decrease of postoperative pain, trismus, and swelling. Furthermore, it enhances bone quality within the extraction socket and bone quantity along the distal aspect of the mandibular second molar.

  2. Comparison of Carbon Dioxide Laser With Surgical Blade for Removal of Epulis Fissuratum. A Randomized Clinical Trial

    Science.gov (United States)

    Karimi, Abbas; Sobouti, Farhad; Torabi, Sara; Bakhshandehfard, Ali; Amirian, Armaghan; Shariati, Mahsa; Morshedi, Ehsan; Barati, Maryam

    2016-01-01

    Introduction: Epulis fissuratum is often formed as a result of a poor fitting denture. The conventional treatment for this fibrous hyperplastic tissue is to excise it using a scalpel and to close the wound by a continuous or an interrupted suture. The increased utilization of lasers in dentistry also includes the utilization of carbon dioxide (CO2) lasers in place of surgical scalpels in soft tissue surgeries. The objective of this study is to assess the feasibility of utilizing CO2 laser in place of scalpel in surgical treatment of epulis fissuratum. Methods: In this clinical trial research (IRCT code: IRCT2016071124969N2), 19 patients were selected with nearly symmetrical epulis fissuratums in the anterior part of the jaws. The hyperplastic tissue was evenly divided into two sections in each patient. One section was randomly selected and cut by CO2 laser and the other section by a surgical scalpel. The wound created by the scalpel was closed by appropriate number of interrupted sutures. Surgery duration and bleeding as well as vestibular depth, re-epithelialization and edema in both sections were noted and recorded after 7 and 14 days postoperatively. Results: The time of surgery and the amount of bleeding during surgery in the laser section was less and the vestibular depth was more than surgical scalpel section (P < 0.05). Surgical scalpel wound at day seventh healed significantly better than the section treated by the CO2 laser (P < 0.05). Wound in both sections healed similarly on day 14 and no statistical difference was observed. Edema presence was also equal in both sides after 7th and 14th following the surgery. Conclusion: According to the results it could be concluded that the use of CO2 laser may result in less surgery time, less bleeding during surgery, more vestibular depth, better re-epithelialization of the wound and less need for suturing. CO2 laser may be a clinically preferred method for surgical treatment of epulis fissuratum. PMID:28144443

  3. Noise-based Stego-ECC

    Directory of Open Access Journals (Sweden)

    Rahardjo Budi

    2014-03-01

    Full Text Available A novel method of inserting noise into stream of ciphered text is proposed. The goal of inserting noise is to increase the level of uncertainty, thus making it harder for an attacker to detect data and noise. This form of steganography is implemented using Elliptic Curve Cryptography (ECC. The process of embedding the noise to the message in the encryption process and removing the noise from the message in the decryption process is proposed in this work by modifying ElGamal to allow auto detection of data and noise.

  4. Effectiveness of Green Tea Mouthwash in Postoperative Pain Control Following Surgical Removal of Impacted Third Molars: Double Blind Randomized Clinical Trial

    Directory of Open Access Journals (Sweden)

    Majid Eshghpour

    2013-07-01

    Full Text Available Background:Pain following surgical removal of impacted molars has remained an important concern among practitioners. Various protocols have been proposed to reduce postoperative pain. However, each one has special side effects and limitations. As green tea possesses anti-inflammatory and antibacterial properties, the aim of the current study was to evaluate the effectiveness of green tea mouthwash in controlling postoperative pain.Materials and methods:In a study with split-mouth and double blind design, 44 patients in need of bilateral removal of impacted third molars underwent randomized surgical extraction; following one surgery patients rinsed with a green tea mouthwash from the first to seventh postoperative day and after other extraction rinsed with placebo mouthwash in the same duration. Both patients and surgeon were blinded to the type of mouthwash. The predictor variable was type of mouthwash and primary outcome variable was postoperative pain measured by visual analogue scale (VAS during first week after surgery. In addition, number of analgesics patients used after surgery recorded. To measure the effect of green tea mouthwash, repeated measures test with confidence interval of 95% was performed.Results:Total of 43 patients with mean age of 24 years underwent total of 86 surgeries. VAS value had no statistically difference prior rinsing among groups (P-value > 0.05. However, the mean value of VAS following rinsing with green tea was statistically lower than placebo in postoperative days of 3–7 (P-value < 0.05. In addition, while rinsing with green tea, patients took significantly lower number of analgesics after surgery (P-value < 0.05. No side effects reported.Conclusion:Green tea mouthwash could be an appropriate and safe choice to control postoperative pain after third molar surgery.

  5. 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

  6. 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…

  7. Association of Behavior With Noise-Induced Hearing Loss Among Attendees of an Outdoor Music Festival: A Secondary Analysis of a Randomized Clinical Trial.

    Science.gov (United States)

    Kraaijenga, Véronique J C; van Munster, J J C M; van Zanten, G A

    2018-06-01

    To date, factors associated with noise-induced hearing loss at music festivals have not yet been analyzed in a single comprehensive data set. In addition, little is known about the hearing loss-associated behavior of music festival attendees. To assess which factors are associated with the occurrence of a temporary threshold shift (TTS) after music exposure and to investigate the behavior of music festival attendees. This prospective post hoc analysis gathered data from a randomized, single-blind clinical trial conducted on September 5, 2015, at an outdoor music festival in Amsterdam, the Netherlands. Adult volunteers with normal hearing were recruited via social media from August 26 through September 3, 2015. Intention to use earplugs was an exclusion criterion. Of 86 volunteers assessed, 51 were included. This post hoc analysis was performed from October 3, 2016, through February 27, 2017. Music festival visit for 4.5 hours. The primary outcome was a TTS on a standard audiogram for the frequencies 3.0- and 4.0-kHz. Multivariable linear regression was performed to determine which factors are associated with a TTS. A questionnaire on behavior, hearing, and tinnitus was distributed to the participants before and after the festival visit. A total of 51 participants were included (18 men [35%] and 33 women [65%]) with a mean (SD) age of 27 (6) years. Mean (SD) threshold change across 3.0 and 4.0 kHz was 5.4 (5.7) dB for the right ear and 4.0 (6.1) dB for the left ear. Earplug use (absolute difference in the left ear, -6.0 dB [95% CI, -8.7 to -3.2 dB]; in the right ear, -6.4 dB [95% CI, -8.8 to -4.1 dB]), quantity of alcohol use (absolute difference per unit in the left ear, 1.1 dB [95% CI, 0.5 to 1.7 dB]; in the right ear, 0.7 dB [95% CI, 0.1 to 1.4 dB]), drug use (absolute difference in the right ear, 6.0 dB [95% CI, 0.9 to 11.1 dB]), and male sex (absolute difference in the right ear, 4.1 dB [95% CI, 0.3 to 5.9 dB]) were independently associated with hearing loss

  8. 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

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

    NARCIS (Netherlands)

    Bagchi, Arunabha; Karandikar, Rajeeva

    1994-01-01

    In the existing `direct¿ white noise theory of nonlinear filtering, the state process is still modelled as a Markov process satisfying an Itô stochastic differential equation, while a `finitely additive¿ white noise is used to model the observation noise. We remove this asymmetry by modelling the

  10. Immediate versus delayed loading of strategic mini dental implants for the stabilization of partial removable dental prostheses: a patient cluster randomized, parallel-group 3-year trial.

    Science.gov (United States)

    Mundt, Torsten; Al Jaghsi, Ahmad; Schwahn, Bernd; Hilgert, Janina; Lucas, Christian; Biffar, Reiner; Schwahn, Christian; Heinemann, Friedhelm

    2016-07-30

    Acceptable short-term survival rates (>90 %) of mini-implants (diameter implants as strategic abutments for a better retention of partial removable dental prosthesis (PRDP) are not available. The purpose of this study is to test the hypothesis that immediately loaded mini-implants show more bone loss and less success than strategic mini-implants with delayed loading. In this four-center (one university hospital, three dental practices in Germany), parallel-group, controlled clinical trial, which is cluster randomized on patient level, a total of 80 partially edentulous patients with unfavourable number and distribution of remaining abutment teeth in at least one jaw will receive supplementary min-implants to stabilize their PRDP. The mini-implant are either immediately loaded after implant placement (test group) or delayed after four months (control group). Follow-up of the patients will be performed for 36 months. The primary outcome is the radiographic bone level changes at implants. The secondary outcome is the implant success as a composite variable. Tertiary outcomes include clinical, subjective (quality of life, satisfaction, chewing ability) and dental or technical complications. Strategic implants under an existing PRDP are only documented for standard-diameter implants. Mini-implants could be a minimal invasive and low cost solution for this treatment modality. The trial is registered at Deutsches Register Klinischer Studien (German register of clinical trials) under DRKS-ID: DRKS00007589 ( www.germanctr.de ) on January 13(th), 2015.

  11. Noise in strong laser-atom interactions: Phase telegraph noise

    International Nuclear Information System (INIS)

    Eberly, J.H.; Wodkiewicz, K.; Shore, B.W.

    1984-01-01

    We discuss strong laser-atom interactions that are subjected to jump-type (random telegraph) random-phase noise. Physically, the jumps may arise from laser fluctuations, from collisions of various kinds, or from other external forces. Our discussion is carried out in two stages. First, direct and partially heuristic calculations determine the laser spectrum and also give a third-order differential equation for the average inversion of a two-level atom on resonance. At this stage a number of general features of the interaction are able to be studied easily. The optical analog of motional narrowing, for example, is clearly predicted. Second, we show that the theory of generalized Poisson processes allows laser-atom interactions in the presence of random telegraph noise of all kinds (not only phase noise) to be treated systematically, by means of a master equation first used in the context of quantum optics by Burshtein. We use the Burshtein equation to obtain an exact expression for the two-level atom's steady-state resonance fluorescence spectrum, when the exciting laser exhibits phase telegraph noise. Some comparisons are made with results obtained from other noise models. Detailed treatments of the effects ofmly jumps, or as a model of finite laser bandwidth effects, in which the laser frequency exhibits random jumps. We show that these two types of frequency noise can be distinguished in light-scattering spectra. We also discuss examples which demonstrate both temporal and spectral motional narrowing, nonexponential correlations, and non-Lorentzian spectra. Its exact solubility in finite terms makes the frequency-telegraph noise model an attractive alternative to the white-noise Ornstein-Uhlenbeck frequency noise model which has been previously applied to laser-atom interactions

  12. 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.

  13. Microbiological analysis after complete or partial removal of carious dentin using two different techniques in primary teeth: A randomized clinical trial

    Directory of Open Access Journals (Sweden)

    Deepak Kumar Singhal

    2016-01-01

    Conclusion: Results suggest the use of partial caries removal in a single session as compared to complete caries removal as a part of treatment of deep lesions in deciduous teeth in order to reduce the risk of pulp exposure. Partial caries removal using ART can be preferred for community settings as public health procedure for caries management.

  14. Noise characteristics of neutron images obtained by cooled CCD device

    International Nuclear Information System (INIS)

    Taniguchi, Ryoichi; Sasaki, Ryoya; Okuda, Shuichi; Okamoto, Ken-Ichi; Ogawa, Yoshihiro; Tsujimoto, Tadashi

    2009-01-01

    The noise characteristics of a cooled CCD device induced by neutron and gamma ray irradiation have been investigated. In the cooled CCD images, characteristic white spot noises (CCD noise) frequently appeared, which have a shape like a pixel in most cases and their brightness is extremely high compared with that of the image pattern. They could be divided into the two groups, fixed pattern noise (FPN) and random noise. The former always appeared in the same position in the image and the latter appeared at any position. In the background image, nearly all of the CCD noises were found to be the FPN, while many of them were the random noise during the irradiation. The random CCD noises increased with irradiation and decreased soon after the irradiation. In the case of large irradiation, a part of the CCD noise remained as the FPN. These facts suggest that the CCD noise is a phenomenon strongly relating to radiation damage of the CCD device.

  15. High level white noise generator

    International Nuclear Information System (INIS)

    Borkowski, C.J.; Blalock, T.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

  16. 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.

  17. 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.

  18. 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.

  19. RTS noise and dark current white defects reduction using selective averaging based on a multi-aperture system.

    Science.gov (United States)

    Zhang, Bo; Kagawa, Keiichiro; Takasawa, Taishi; Seo, Min Woong; Yasutomi, Keita; Kawahito, Shoji

    2014-01-16

    In extremely low-light conditions, random telegraph signal (RTS) noise and dark current white defects become visible. In this paper, a multi-aperture imaging system and selective averaging method which removes the RTS noise and the dark current white defects by minimizing the synthetic sensor noise at every pixel is proposed. In the multi-aperture imaging system, a very small synthetic F-number which is much smaller than 1.0 is achieved by increasing optical gain with multiple lenses. It is verified by simulation that the effective noise normalized by optical gain in the peak of noise histogram is reduced from 1.38e⁻ to 0.48 e⁻ in a 3 × 3-aperture system using low-noise CMOS image sensors based on folding-integration and cyclic column ADCs. In the experiment, a prototype 3 × 3-aperture camera, where each aperture has 200 × 200 pixels and an imaging lens with a focal length of 3.0 mm and F-number of 3.0, is developed. Under a low-light condition, in which the maximum average signal is 11e⁻ per aperture, the RTS and dark current white defects are removed and the peak signal-to-noise ratio (PSNR) of the image is increased by 6.3 dB.

  20. Fractals in Power Reactor Noise

    International Nuclear Information System (INIS)

    Aguilar Martinez, O.

    1994-01-01

    In this work the non- lineal dynamic problem of power reactor is analyzed using classic concepts of fractal analysis as: attractors, Hausdorff-Besikovics dimension, phase space, etc. A new non-linear problem is also analyzed: the discrimination of chaotic signals from random neutron noise signals and processing for diagnosis purposes. The advantages of a fractal analysis approach in the power reactor noise are commented in details

  1. 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.

  2. Elimination of noise peak for signal processing in Johnson noise thermometry development

    International Nuclear Information System (INIS)

    Hwang, I. G.; Moon, B. S.; Jeong, J. E.; Jeo, Y. H.; Kisner, Roger A.

    2003-01-01

    The internal and external noise is the most considering obstacle in development of Johnson Noise Thermometry system. This paper addresses an external noise elimination issue of the Johnson Noise Thermometry system which is underway of development in collaboration between KAERI and ORNL. Although internal random noise is canceled by Cross Power Spectral Density function, a continuous wave penetrating into the electronic circuit is eliminated by the difference of peaks between Johnson signal and external noise. The elimination logic using standard deviation of CPSD and energy leakage problem in discrete CPSD function are discussed in this paper

  3. Reduction method for residual stress of welded joint using random vibration

    International Nuclear Information System (INIS)

    Aoki, Shigeru; Nishimura, Tadashi; Hiroi, Tetsumaro

    2005-01-01

    Welded joints are used for construction of many structures. Residual stress is induced near the bead caused by locally given heat. Tensile residual stress on the surface may reduce fatigue strength. In this paper, a new method for reduction of residual stress using vibration during welding is proposed. As vibrational load, random vibration, white noise and filtered white noise are used. Two thin plates are butt-welded. Residual stress is measured with a paralleled beam X-ray diffractometer with scintillation counter after removing quenched scale chemically. It is concluded that tensile residual stress near the bead is reduced by using random vibration during welding

  4. Hair Removal

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Hair Removal KidsHealth / For Teens / Hair Removal What's in ... you need any of them? Different Types of Hair Before removing hair, it helps to know about ...

  5. Early sheath removal after percutaneous coronary intervention using Assiut Femoral Compression Device is feasible and safe. Results of a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Ayman K.M. Hassan

    2015-03-01

    Conclusion: Our results indicate that AFCD2 is a simple and effective alternative to MC for hemostasis following PCI. Early sheath removal 2 h post PCI is feasible, safe, and improves the patient’s comfort.

  6. Hair removal in hirsute women with normal testosterone levels: a randomized controlled trial of long-pulsed diode laser vs. intense pulsed light

    DEFF Research Database (Denmark)

    Haak, C S; Jensen, Pernille Nymann; Pedersen, A T

    2010-01-01

    Hirsutism is a common disorder in women of reproductive age, and androgen disturbances may aggravate the condition. Limited evidence exists regarding efficacy of hair removal in this specific population and no data are available for patients with verified normal testosterone levels.......Hirsutism is a common disorder in women of reproductive age, and androgen disturbances may aggravate the condition. Limited evidence exists regarding efficacy of hair removal in this specific population and no data are available for patients with verified normal testosterone levels....

  7. A high speed digital noise generator

    Science.gov (United States)

    Obrien, J.; Gaffney, B.; Liu, B.

    In testing of digital signal processing hardware, a high speed pseudo-random noise generator is often required to simulate an input noise source to the hardware. This allows the hardware to be exercised in a manner analogous to actual operating conditions. In certain radar and communication environments, a noise generator operating at speeds in excess of 60 MHz may be required. In this paper, a method of generating high speed pseudo-random numbers from an arbitrarily specified distribution (Gaussian, Log-Normal, etc.) using a transformation from a uniform noise source is described. A noise generator operating at 80 MHz has been constructed. Different distributions can be readily obtained by simply changing the ROM set. The hardware and test results will be described. Using this approach, the generation of pseudo-random sequences with arbitrary distributions at word rates in excess of 200 MHz can be readily achieved.

  8. Noise Tomography and Adaptive Illumination in Noise Radar

    Science.gov (United States)

    2015-10-01

    transform of scatu , defined in (2.15), in y–direction can be written as 2 ( , , ) ( , ) 2 j dn n scat n y scat n y k EU k x d k e O k k j...and J. A. Henning , "Radar penetration imaging using ultra- wideband (UWB) random noise waveforms," IEE Proceedings-Radar Sonar and Navigation, vol

  9. 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....

  10. A new noise erosion operator for anisotropic diffusion

    Institute of Scientific and Technical Information of China (English)

    蔡超; 丁名跃; 周成平; 张天序

    2004-01-01

    A noise erosion operator based on partial differential equation (PDE) is introduced, which has an excellent ability of noise removal and edge preservation for two-dimensional (2D) gradient data. The operator is applied to estimate a new diffusion coefficient. Experimental results demonstrate that anisotropic diffusion based on this new erosion operator can efficiently reduce noise and sharpen object boundaries.

  11. Generalised shot noise Cox processes

    DEFF Research Database (Denmark)

    Møller, Jesper; Torrisi, Giovanni Luca

    We introduce a new class of Cox cluster processes called generalised shot-noise processes (GSNCPs), which extends the definition of shot noise Cox processes (SNCPs) in two directions: the point process which drives the shot noise is not necessarily Poisson, and the kernel of the shot noise can...... be random. Thereby a very large class of models for aggregated or clustered point patterns is obtained. Due to the structure of GSNCPs, a number of useful results can be established. We focus first on deriving summary statistics for GSNCPs and next on how to make simulation for GSNCPs. Particularly, results...... for first and second order moment measures, reduced Palm distributions, the -function, simulation with or without edge effects, and conditional simulation of the intensity function driving a GSNCP are given. Our results are exemplified for special important cases of GSNCPs, and we discuss the relation...

  12. Noise pollution resources compendium

    Science.gov (United States)

    1973-01-01

    Abstracts of reports concerning noise pollution are presented. The abstracts are grouped in the following areas of activity: (1) sources of noise, (2) noise detection and measurement, (3) noise abatement and control, (4) physical effects of noise and (5) social effects of noise.

  13. Yesterday's noise - today's signal

    International Nuclear Information System (INIS)

    Serdula, K.J.

    1978-01-01

    Plant performance can be improved by noise analysis. This paper describes noise characteristics, imposed noise and response functions, a case history of cost benefits derived from application of noise analysis techniques, areas for application of noise analysis techniques with special reference to the Gentilly-1 nuclear generating station, and the validity of noise measurement results. (E.C.B.)

  14. 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...

  15. Cross over of recurrence networks to random graphs and random ...

    Indian Academy of Sciences (India)

    2017-01-27

    Jan 27, 2017 ... that all recurrence networks can cross over to random geometric graphs by adding sufficient amount of noise to .... municative [19] or social [20], deviate from the random ..... He has shown that the spatial effects become.

  16. Quantum Noise

    International Nuclear Information System (INIS)

    Beenakker, C W J

    2005-01-01

    Quantum Noise is advertised as a handbook, and this is indeed how it functions for me these days: it is a book that I keep within hand's reach, ready to be consulted on the proper use of quantum stochastic methods in the course of my research on quantum dots. I should point out that quantum optics, the target field for this book, is not my field by training. So I have much to learn, and find this handbook to be a reliable and helpful guide. Crispin Gardiner previously wrote the Handbook of Stochastic Methods (also published by Springer), which provides an overview of methods in classical statistical physics. Quantum Noise, written jointly with Peter Zoller, is the counterpart for quantum statistical physics, and indeed the two books rely on each other by frequent cross referencing. The fundamental problem addressed by Quantum Noise is how the quantum dynamics of an open system can be described statistically by treating the environment as a source of noise. This is a general problem in condensed matter physics (in particular in the context of Josephson junctions) and in quantum optics. The emphasis in this book in on the optical applications (for condensed matter applications one could consult Quantum Dissipative Systems by Ulrich Weiss, published by World Scientific). The optical applications centre around the interaction of light with atoms, where the atoms represent the open system and the light is the noisy environment. A complete description of the production and detection of non-classical states of radiation (such as squeezed states) can be obtained using one of the equivalent quantum stochastic formulations: the quantum Langevin equation for the field operators (in either the Ito or the Stratonovich form), the Master equation for the density matrix, or the stochastic Schroedinger equation for the wave functions. Each formulation is fully developed here (as one would expect from a handbook), with detailed instructions on how to go from one to the other. The

  17. Hair removal in hirsute women with normal testosterone levels: a randomized controlled trial of long-pulsed diode laser vs. intense pulsed light

    DEFF Research Database (Denmark)

    Haak, C S; Jensen, Pernille Nymann; Pedersen, A T

    2010-01-01

    Hirsutism is a common disorder in women of reproductive age, and androgen disturbances may aggravate the condition. Limited evidence exists regarding efficacy of hair removal in this specific population and no data are available for patients with verified normal testosterone levels....

  18. 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.

  19. Examining nocturnal railway noise and aircraft noise in the field: sleep, psychomotor performance, and annoyance.

    Science.gov (United States)

    Elmenhorst, Eva-Maria; Pennig, Sibylle; Rolny, Vinzent; Quehl, Julia; Mueller, Uwe; Maaß, Hartmut; Basner, Mathias

    2012-05-01

    Traffic noise is interfering during day- and nighttime causing distress and adverse physiological reactions in large parts of the population. Railway noise proved less annoying than aircraft noise in surveys which were the bases for a so called 5 dB railway bonus regarding noise protection in many European countries. The present field study investigated railway noise-induced awakenings during sleep, nighttime annoyance and the impact on performance the following day. Comparing these results with those from a field study on aircraft noise allowed for a ranking of traffic modes concerning physiological and psychological reactions. 33 participants (mean age 36.2 years ± 10.3 (SD); 22 females) living alongside railway tracks around Cologne/Bonn (Germany) were polysomnographically investigated. These data were pooled with data from a field study on aircraft noise (61 subjects) directly comparing the effects of railway and aircraft noise in one random subject effects logistic regression model. Annoyance was rated in the morning evaluating the previous night. Probability of sleep stage changes to wake/S1 from railway noise increased significantly from 6.5% at 35 dB(A) to 20.5% at 80 dB(A) LAFmax. Rise time of noise events had a significant impact on awakening probability. Nocturnal railway noise led to significantly higher awakening probabilities than aircraft noise, partly explained by the different rise times, whereas the order was inversed for annoyance. Freight train noise compared to passenger train noise proved to have the most impact on awakening probability. Nocturnal railway noise had no effect on psychomotor vigilance. Nocturnal freight train noise exposure in Germany was associated with increased awakening probabilities exceeding those for aircraft noise and contrasting the findings of many annoyance surveys and annoyance ratings of our study. During nighttime a bonus for railway noise seems not appropriate. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Adaptive Noise Canceling Menggunakan Algoritma Least Mean Square (Lms)

    OpenAIRE

    Nardiana, Anita; Sumaryono, Sari Sujoko

    2011-01-01

    Noise is inevitable in communication system. In some cases, noise can disturb signal. It is veryannoying as the received signal is jumbled with the noise itself. To reduce or remove noise, filter lowpass,highpass or bandpass can solve the problems, but this method cannot reach a maximum standard. One ofthe alternatives to solve the problem is by using adaptive filter. Adaptive algorithm frequently used is LeastMean Square (LMS) Algorithm which is compatible to Finite Impulse Response (FIR). T...

  1. Noise thermometer

    Energy Technology Data Exchange (ETDEWEB)

    Von Brixy, H. [Forschungszentrum Juelich GmbH (Germany); Kakuta, Tsunemi

    1996-03-01

    The noise thermometry (NT) is a temperature measuring method by which the absolute temperature measurement can be performed with a very high accuracy and without any influence of ambient environments and of the thermal history of its NT sensor (electric resistor). Hence it is quite suitable for application as a standard thermometry to the in-situ temperature calibration of incore thermocouples. The KFA Juelich had played a pioneering role in the development of NT and applied the results successfully to the AVR for testing its feasibility. In this report, all about the NT including its principle, sensor elements and system configurations are presented together with the experiences in the AVR and the results of investigation to apply it to high temperature measurement. The NT can be adopted as a standard method for incore temperature measurement and in situ temperature calibration in the HTTR. (author). 85 refs.

  2. Noise thermometer

    International Nuclear Information System (INIS)

    Von Brixy, H.; Kakuta, Tsunemi.

    1996-03-01

    The noise thermometry (NT) is a temperature measuring method by which the absolute temperature measurement can be performed with a very high accuracy and without any influence of ambient environments and of the thermal history of its NT sensor (electric resistor). Hence it is quite suitable for application as a standard thermometry to the in-situ temperature calibration of incore thermocouples. The KFA Juelich had played a pioneering role in the development of NT and applied the results successfully to the AVR for testing its feasibility. In this report, all about the NT including its principle, sensor elements and system configurations are presented together with the experiences in the AVR and the results of investigation to apply it to high temperature measurement. The NT can be adopted as a standard method for incore temperature measurement and in situ temperature calibration in the HTTR. (author). 85 refs

  3. The influence of CT image noise on proton range calculation in radiotherapy planning

    International Nuclear Information System (INIS)

    Chvetsov, Alexei V; Paige, Sandra L

    2010-01-01

    The purpose of this note is to evaluate the relationship between the stochastic errors in CT numbers and the standard deviation of the computed proton beam range in radiotherapy planning. The stochastic voxel-to-voxel variation in CT numbers called 'noise,' may be due to signal registration, processing and numerical image reconstruction technique. Noise in CT images may cause a deviation in the computed proton range from the physical proton range, even assuming that the error due to CT number-stopping power calibration is removed. To obtain the probability density function (PDF) of the computed proton range, we have used the continuing slowing down approximation (CSDA) and the uncorrelated white Gaussian noise along the proton path. The model of white noise was accepted because for the slice-based fan-beam CT scanner; the power-spectrum properties apply only to the axial (x, y) domain and the noise is uncorrelated in the z domain. However, the possible influence of the noise power spectrum on the standard deviation of the range should be investigated in the future. A random number generator was utilized for noise simulation and this procedure was iteratively repeated to obtain convergence of range PDF, which approached a Gaussian distribution. We showed that the standard deviation of the range, σ, increases linearly with the initial proton energy, computational grid size and standard deviation of the voxel values. The 95% confidence interval width of the range PDF, which is defined as 4σ, may reach 0.6 cm for the initial proton energy of 200 MeV, computational grid 0.25 cm and 5% standard deviation of CT voxel values. Our results show that the range uncertainty due to random errors in CT numbers may be significant and comparable to the uncertainties due to calibration of CT numbers. (note)

  4. When noise is beneficial for sensory encoding: Noise adaptation can improve face processing.

    Science.gov (United States)

    Menzel, Claudia; Hayn-Leichsenring, Gregor U; Redies, Christoph; Németh, Kornél; Kovács, Gyula

    2017-10-01

    The presence of noise usually impairs the processing of a stimulus. Here, we studied the effects of noise on face processing and show, for the first time, that adaptation to noise patterns has beneficial effects on face perception. We used noiseless faces that were either surrounded by random noise or presented on a uniform background as stimuli. In addition, the faces were either preceded by noise adaptors or not. Moreover, we varied the statistics of the noise so that its spectral slope either matched that of the faces or it was steeper or shallower. Results of parallel ERP recordings showed that the background noise reduces the amplitude of the face-evoked N170, indicating less intensive face processing. Adaptation to a noise pattern, however, led to reduced P1 and enhanced N170 amplitudes as well as to a better behavioral performance in two of the three noise conditions. This effect was also augmented by the presence of background noise around the target stimuli. Additionally, the spectral slope of the noise pattern affected the size of the P1, N170 and P2 amplitudes. We reason that the observed effects are due to the selective adaptation of noise-sensitive neurons present in the face-processing cortical areas, which may enhance the signal-to-noise-ratio. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Speech production in amplitude-modulated noise

    DEFF Research Database (Denmark)

    Macdonald, Ewen N; Raufer, Stefan

    2013-01-01

    The Lombard effect refers to the phenomenon where talkers automatically increase their level of speech in a noisy environment. While many studies have characterized how the Lombard effect influences different measures of speech production (e.g., F0, spectral tilt, etc.), few have investigated...... 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...... of noisy environments and will alter their speech accordingly....

  6. 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

  7. Trajectories of Brownian particles with space-correlated noise

    Indian Academy of Sciences (India)

    EDOARDO MILOTTI

    walks with spatially correlated white noise: the time- dependence of the distance of pairs of random walkers. ... Dedicated to the memory of the late Professor Charusita Chakravarty. also quite well-known that the two-sided noise .... due to the individual noise components, we find that in the present context the value of ξ2 is.

  8. 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.

  9. Noise-induced effects in population dynamics

    Science.gov (United States)

    Spagnolo, Bernardo; Cirone, Markus; La Barbera, Antonino; de Pasquale, Ferdinando

    2002-03-01

    We investigate the role of noise in the nonlinear relaxation of two ecosystems described by generalized Lotka-Volterra equations in the presence of multiplicative noise. Specifically we study two cases: (i) an ecosystem with two interacting species in the presence of periodic driving; (ii) an ecosystem with a great number of interacting species with random interaction matrix. We analyse the interplay between noise and periodic modulation for case (i) and the role of the noise in the transient dynamics of the ecosystem in the presence of an absorbing barrier in case (ii). We find that the presence of noise is responsible for the generation of temporal oscillations and for the appearance of spatial patterns in the first case. In the other case we obtain the asymptotic behaviour of the time average of the ith population and discuss the effect of the noise on the probability distributions of the population and of the local field.

  10. Sub-1-V-60 nm vertical body channel MOSFET-based six-transistor static random access memory array with wide noise margin and excellent power delay product and its optimization with the cell ratio on static random access memory cell

    Science.gov (United States)

    Ogasawara, Ryosuke; Endoh, Tetsuo

    2018-04-01

    In this study, with the aim to achieve a wide noise margin and an excellent power delay product (PDP), a vertical body channel (BC)-MOSFET-based six-transistor (6T) static random access memory (SRAM) array is evaluated by changing the number of pillars in each part of a SRAM cell, that is, by changing the cell ratio in the SRAM cell. This 60 nm vertical BC-MOSFET-based 6T SRAM array realizes 0.84 V operation under the best PDP and up to 31% improvement of PDP compared with the 6T SRAM array based on a 90 nm planar MOSFET whose gate length and channel width are the same as those of the 60 nm vertical BC-MOSFET. Additionally, the vertical BC-MOSFET-based 6T SRAM array achieves an 8.8% wider read static noise margin (RSNM), a 16% wider write margin (WM), and an 89% smaller leakage. Moreover, it is shown that changing the cell ratio brings larger improvements of RSNM, WM, and write time in the vertical BC-MOSFET-based 6T SRAM array.

  11. Removing cosmic rays and other randomly positioned spurious events from CCD images by taking the lesser image -statistical theory for the general case

    International Nuclear Information System (INIS)

    Kay, L.

    1992-01-01

    If two optical images of the same scene are obtained using a charged-coupled device (CCD), a third image (called the lesser image) may be formed in computer memory by taking the lesser of the two counts in each pixel. The process may be used to remove, or greatly reduce, the effect of spurious events such as cosmic rays. A complete statistical theory of the lesser image is given for the general case, thereby facilitating recovery of the true image from the lesser image. (author)

  12. 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.

  13. Feedback-tuned, noise resilient gates for encoded spin qubits

    Science.gov (United States)

    Bluhm, Hendrik

    Spin 1/2 particles form native two level systems and thus lend themselves as a natural qubit implementation. However, encoding a single qubit in several spins entails benefits, such as reducing the resources necessary for qubit control and protection from certain decoherence channels. While several varieties of such encoded spin qubits have been implemented, accurate control remains challenging, and leakage out of the subspace of valid qubit states is a potential issue. Optimal performance typically requires large pulse amplitudes for fast control, which is prone to systematic errors and prohibits standard control approaches based on Rabi flopping. Furthermore, the exchange interaction typically used to electrically manipulate encoded spin qubits is inherently sensitive to charge noise. I will discuss all-electrical, high-fidelity single qubit operations for a spin qubit encoded in two electrons in a GaAs double quantum dot. Starting from a set of numerically optimized control pulses, we employ an iterative tuning procedure based on measured error syndromes to remove systematic errors.Randomized benchmarking yields an average gate fidelity exceeding 98 % and a leakage rate into invalid states of 0.2 %. These gates exhibit a certain degree of resilience to both slow charge and nuclear spin fluctuations due to dynamical correction analogous to a spin echo. Furthermore, the numerical optimization minimizes the impact of fast charge noise. Both types of noise make relevant contributions to gate errors. The general approach is also adaptable to other qubit encodings and exchange based two-qubit gates.

  14. Noise and Hearing Protection

    Science.gov (United States)

    ... ENTCareers Marketplace Find an ENT Doctor Near You Noise and Hearing Protection Noise and Hearing Protection Patient ... it is. How can I tell if a noise is dangerous? People differ in their sensitivity to ...

  15. Analysis of Noise Mechanisms in Cell-Size Control.

    Science.gov (United States)

    Modi, Saurabh; Vargas-Garcia, Cesar Augusto; Ghusinga, Khem Raj; Singh, Abhyudai

    2017-06-06

    At the single-cell level, noise arises from multiple sources, such as inherent stochasticity of biomolecular processes, random partitioning of resources at division, and fluctuations in cellular growth rates. How these diverse noise mechanisms combine to drive variations in cell size within an isoclonal population is not well understood. Here, we investigate the contributions of different noise sources in well-known paradigms of cell-size control, such as adder (division occurs after adding a fixed size from birth), sizer (division occurs after reaching a size threshold), and timer (division occurs after a fixed time from birth). Analysis reveals that variation in cell size is most sensitive to errors in partitioning of volume among daughter cells, and not surprisingly, this process is well regulated among microbes. Moreover, depending on the dominant noise mechanism, different size-control strategies (or a combination of them) provide efficient buffering of size variations. We further explore mixer models of size control, where a timer phase precedes/follows an adder, as has been proposed in Caulobacter crescentus. Although mixing a timer and an adder can sometimes attenuate size variations, it invariably leads to higher-order moments growing unboundedly over time. This results in a power-law distribution for the cell size, with an exponent that depends inversely on the noise in the timer phase. Consistent with theory, we find evidence of power-law statistics in the tail of C. crescentus cell-size distribution, although there is a discrepancy between the observed power-law exponent and that predicted from the noise parameters. The discrepancy, however, is removed after data reveal that the size added by individual newborns in the adder phase itself exhibits power-law statistics. Taken together, this study provides key insights into the role of noise mechanisms in size homeostasis, and suggests an inextricable link between timer-based models of size control and

  16. Dynamics and bifurcations of random circle diffeomorphisms

    NARCIS (Netherlands)

    Zmarrou, H.; Homburg, A.J.

    2008-01-01

    We discuss iterates of random circle diffeomorphisms with identically distributed noise, where the noise is bounded and absolutely continuous. Using arguments of B. Deroin, V.A. Kleptsyn and A. Navas, we provide precise conditions under which random attracting fixed points or random attracting

  17. Non-Markovian noise

    International Nuclear Information System (INIS)

    Fulinski, A.

    1994-01-01

    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 δ 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

  18. Noise in ecosystems: a short review.

    Science.gov (United States)

    Spagnolo, B; Valenti, D; Fiasconaro, A

    2004-06-01

    Noise, through its interaction with the nonlinearity of the living systems, can give rise to counter-intuitive phenomena such as stochastic resonance, noise-delayed extinction, temporal oscillations, and spatial patterns. In this paper we briefly review the noise-induced effects in three different ecosystems: (i) two competing species; (ii) three interacting species, one predator and two preys, and (iii) N-interacting species. The transient dynamics of these ecosystems are analyzed through generalized Lotka-Volterra equations in the presence of multiplicative noise, which models the interaction between the species and the environment. The interaction parameter between the species is random in cases (i) and (iii), and a periodical function, which accounts for the environmental temperature, in case (ii). We find noise-induced phenomena such as quasi-deterministic oscillations, stochastic resonance, noise-delayed extinction, and noise-induced pattern formation with nonmonotonic behaviors of patterns areas and of the density correlation as a function of the multiplicative noise intensity. The asymptotic behavior of the time average of the i(th) population when the ecosystem is composed of a great number of interacting species is obtained and the effect of the noise on the asymptotic probability distributions of the populations is discussed.

  19. Noise enhances information transfer in hierarchical networks.

    Science.gov (United States)

    Czaplicka, Agnieszka; Holyst, Janusz A; Sloot, Peter M A

    2013-01-01

    We study the influence of noise on information transmission in the form of packages shipped between nodes of hierarchical networks. Numerical simulations are performed for artificial tree networks, scale-free Ravasz-Barabási networks as well for a real network formed by email addresses of former Enron employees. Two types of noise are considered. One is related to packet dynamics and is responsible for a random part of packets paths. The second one originates from random changes in initial network topology. We find that the information transfer can be enhanced by the noise. The system possesses optimal performance when both kinds of noise are tuned to specific values, this corresponds to the Stochastic Resonance phenomenon. There is a non-trivial synergy present for both noisy components. We found also that hierarchical networks built of nodes of various degrees are more efficient in information transfer than trees with a fixed branching factor.

  20. Spleen removal

    Science.gov (United States)

    ... spleen. Sickle cell anemia . Splenic artery aneurysm (rare). Trauma to the spleen. Risks Risks for anesthesia and surgery in general ... removal - series References Brandow AM, Camitta BM. Hyposplenism, splenic trauma, and splenectomy. In: Kliegman RM, Stanton BF, St. ...

  1. Long-pulsed Nd:YAG laser vs. intense pulsed light for hair removal in dark skin: a randomized controlled trial.

    Science.gov (United States)

    Ismail, S A

    2012-02-01

    Although several lasers meet the wavelength criteria for selective follicular destruction, the treatment of darker skin phototypes is particularly challenging because absorption of laser energy by the targeted hairs is compromised by an increased concentration of epidermal melanin. To compare satisfaction level, safety and effectiveness of a long-pulsed Nd:YAG laser and intense pulsed light (IPL) in axillary hair reduction in subjects with dark skin. The study design was a within-patient, right-left, assessor-blinded, comparison of long-pulsed Nd:YAG laser and IPL. Fifty women (skin phototypes IV-VI) volunteered for removal of axillary hair. Five sessions at 4- to 6-week intervals were performed. Hair counts at both sides were compared at baseline and 6months after the last session. Final overall evaluations were performed by subjects and clinician at the end of the study. Satisfaction was scored for both devices. Thirty-nine women completed the study. At 6months, the decrease in hair counts on the laser side (79·4%, Pvs. pretreatment) was significantly (Pvs. pretreatment). Only temporary adverse effects were reported at both sides. Higher pain scores and more inflammation were reported with Nd:YAG laser; however, it was preferred by 29 volunteers (74%). Volunteers reported higher satisfaction score with Nd:YAG laser (PDark skin can be treated by both systems safely and effectively; however, long-pulsed (1064 nm) Nd:YAG laser is more effective as reported by both subjects and clinician. © 2011 The Authors. BJD © 2011 British Association of Dermatologists.

  2. Noise level and MPEG-2 encoder statistics

    Science.gov (United States)

    Lee, Jungwoo

    1997-01-01

    Most software in the movie and broadcasting industries are still in analog film or tape format, which typically contains random noise that originated from film, CCD camera, and tape recording. The performance of the MPEG-2 encoder may be significantly degraded by the noise. It is also affected by the scene type that includes spatial and temporal activity. The statistical property of noise originating from camera and tape player is analyzed and the models for the two types of noise are developed. The relationship between the noise, the scene type, and encoder statistics of a number of MPEG-2 parameters such as motion vector magnitude, prediction error, and quant scale are discussed. This analysis is intended to be a tool for designing robust MPEG encoding algorithms such as preprocessing and rate control.

  3. Topical eflornithine hydrochloride improves the effectiveness of standard laser hair removal for treating pseudofolliculitis barbae: a randomized, double-blinded, placebo-controlled trial.

    Science.gov (United States)

    Xia, Yang; Cho, Sunghun; Howard, Robin S; Maggio, Kurt L

    2012-10-01

    Pseudofolliculitis barbae (PFB) significantly impacts the military population, especially deployed personnel. This study was designed to determine whether the addition of topical eflornithine to hair laser treatment would improve efficacy in treating PFB. This was a randomized, double-blinded, placebo-controlled, paired (right and left neck) comparison study examining a combination of eflornithine and hair laser versus placebo and hair laser for the treatment of PFB. In all, 27 male patients with clinical PFB were treated with a long-pulsed neodymium:yttrium-aluminum-garnet laser with an energy fluence of 25 to 30 J/cm(2), a pulse duration of 20 to 30 milliseconds, and a 10-mm spot size to the entire bearded neck region. The laser treatment was performed every 4 weeks for a total of 16 weeks. Between laser treatments, patients applied eflornithine and placebo creams twice daily to opposite sides of the bearded neck region. The number of hairs and inflammatory papules were counted bilaterally at each visit. The eflornithine side had a statistically significant decrease in the number of hairs and inflammatory papules compared with the placebo side. At 16 weeks, the eflornithine side had a median hair reduction of 99.5% from baseline (range 48.5%-100.0%), whereas the placebo side had an 85.0% median hair reduction from baseline (range 50.5%-94.5%), P less than .001. Patients were not followed up beyond 16 weeks. The addition of topical eflornithine to hair laser treatment decreased hairs and inflammatory papules faster when compared with hair laser therapy alone in the treatment of PFB. Copyright © 2011 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.

  4. 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.

  5. Surveillance of instruments by noise analysis

    International Nuclear Information System (INIS)

    Thie, J.A.

    1981-01-01

    Random fluctuations of neutron flux, temperature, and pressure in a reactor provide multifrequency excitation of the corresponding instrumentation chains. Mathematical descriptors suitable for characterizing the output, or noise, of the instrumentation are reviewed with a view toward using such noise in detecting instrument faults. Demonstrations of the feasibility of this approach in a number of reactors provide illustrative examples. Comparisons with traditional surveillance testing are made, and a number of advantages and some disadvantages of using noise analysis as a supplementary technique are pointed out

  6. Noise-Induced Riddling in Chaotic Systems

    International Nuclear Information System (INIS)

    Lai, Y.; Grebogi, C.

    1996-01-01

    Recent works have considered the situation of riddling where, when a chaotic attractor lying in an invariant subspace is transversely stable, the basin of the attractor can be riddled with holes that belong to the basin of another attractor. We show that riddling can be induced by arbitrarily small random noise even if the attractor is transversely unstable, and we obtain universal scaling laws for noise-induced riddling. Our results imply that the phenomenon of riddling can be more prevalent than expected before, as noise is practically inevitable in dynamical systems. copyright 1996 The American Physical Society

  7. 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

  8. Hair Removal

    DEFF Research Database (Denmark)

    Hædersdal, Merete

    2011-01-01

    Hair removal with optical devices has become a popular mainstream treatment that today is considered the most efficient method for the reduction of unwanted hair. Photothermal destruction of hair follicles constitutes the fundamental concept of hair removal with red and near-infrared wavelengths...... suitable for targeting follicular and hair shaft melanin: normal mode ruby laser (694 nm), normal mode alexandrite laser (755 nm), pulsed diode lasers (800, 810 nm), long-pulse Nd:YAG laser (1,064 nm), and intense pulsed light (IPL) sources (590-1,200 nm). The ideal patient has thick dark terminal hair......, white skin, and a normal hormonal status. Currently, no method of lifelong permanent hair eradication is available, and it is important that patients have realistic expectations. Substantial evidence has been found for short-term hair removal efficacy of up to 6 months after treatment with the available...

  9. Hair removal

    DEFF Research Database (Denmark)

    Haedersdal, Merete; Haak, Christina S

    2011-01-01

    Hair removal with optical devices has become a popular mainstream treatment that today is considered the most efficient method for the reduction of unwanted hair. Photothermal destruction of hair follicles constitutes the fundamental concept of hair removal with red and near-infrared wavelengths...... suitable for targeting follicular and hair shaft melanin: normal mode ruby laser (694 nm), normal mode alexandrite laser (755 nm), pulsed diode lasers (800, 810 nm), long-pulse Nd:YAG laser (1,064 nm), and intense pulsed light (IPL) sources (590-1,200 nm). The ideal patient has thick dark terminal hair......, white skin, and a normal hormonal status. Currently, no method of lifelong permanent hair eradication is available, and it is important that patients have realistic expectations. Substantial evidence has been found for short-term hair removal efficacy of up to 6 months after treatment with the available...

  10. Mixed Gaussian-Impulse Noise Image Restoration Via Total Variation

    Science.gov (United States)

    2012-05-01

    deblurring under impulse noise ,” J. Math. Imaging Vis., vol. 36, pp. 46–53, January 2010. [5] B. Li, Q. Liu, J. Xu, and X. Luo, “A new method for removing......Several Total Variation (TV) regularization methods have recently been proposed to address denoising under mixed Gaussian and impulse noise . While

  11. Time response measurements of pressure sensors using pink noise technique

    International Nuclear Information System (INIS)

    Pereira, Iraci Martinez; Santos, Roberto Carlos dos

    2009-01-01

    This work presents an experimental setup for Pink Noise method application on pressure transmitters' response times. The Pink Noise method consists on injecting artificial pressure noise into the pressure transmitter. The artificial pressure noise is generated using a current-to-pressure (I-to-P) converter, which is driven by a random noise signal generator. The output pressure transmitter noise is then analyzed using conventional Noise Analysis Technique. Noise signals may be interpreted using spectral techniques or empirical time series models. The frequency domain method consists of evaluating the Power Spectral Density (PSD) function. The information needed for time constant estimation can be obtained by fitting an all-pole transfer function to this power spectral density. (author)

  12. 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.

  13. 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

  14. Neutron noise in nuclear reactors

    International Nuclear Information System (INIS)

    Blaquiere, A.; Pachowska, R.

    1961-06-01

    The power of a nuclear reactor, in the operating conditions, presents fluctuations due to various causes. This random behaviour can be included in the study of 'noises'. Among other sources of noise, we analyse hereafter the fluctuations due: a) to the discontinuous emissions of neutrons from an independent source; b) to the multiplication of neutrons inside the reactor. The method which we present makes use of the analogies between the rules governing a nuclear reactor in operation and a number of radio-electrical systems, in particular the feed-back loops. The reactor can be characterized by its 'passing band' and is described as a system submitted to a sequence of random pulses. In non linear operating condition, the effect of neutron noise is defined by means of a non-linear functional, this theory is thus related to previous works the references of which are given at the end of the present report. This leads us in particular in the case of nuclear reactors to some results given by A. Blaquiere in the case of radio-electrical loops. (author) [fr

  15. NASA Jet Noise Research

    Science.gov (United States)

    Henderson, Brenda

    2016-01-01

    The presentation highlights NASA's jet noise research for 2016. Jet-noise modeling efforts, jet-surface interactions results, acoustic characteristics of multi-stream jets, and N+2 Supersonic Aircraft system studies are presented.

  16. Local noise in a diffusive conductor

    Science.gov (United States)

    Tikhonov, E. S.; Shovkun, D. V.; Ercolani, D.; Rossella, F.; Rocci, M.; Sorba, L.; Roddaro, S.; Khrapai, V. S.

    2016-07-01

    The control and measurement of local non-equilibrium configurations is of utmost importance in applications on energy harvesting, thermoelectrics and heat management in nano-electronics. This challenging task can be achieved with the help of various local probes, prominent examples including superconducting or quantum dot based tunnel junctions, classical and quantum resistors, and Raman thermography. Beyond time-averaged properties, valuable information can also be gained from spontaneous fluctuations of current (noise). From these perspective, however, a fundamental constraint is set by current conservation, which makes noise a characteristic of the whole conductor, rather than some part of it. Here we demonstrate how to remove this obstacle and pick up a local noise temperature of a current biased diffusive conductor with the help of a miniature noise probe. This approach is virtually noninvasive for the electronic energy distributions and extends primary local measurements towards strongly non-equilibrium regimes.

  17. 40 CFR 211.214 - Removal of label.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Removal of label. 211.214 Section 211... PRODUCT NOISE LABELING Hearing Protective Devices § 211.214 Removal of label. Section 10(a)(4) of the Act prohibits any person from removing, prior to sale, any label required by this subpart, by either physical...

  18. 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...

  19. Noise Reduction Techniques

    Science.gov (United States)

    Hallas, Tony

    There are two distinct kinds of noise - structural and color. Each requires a specific method of attack to minimize. The great challenge is to reduce the noise without reducing the faint and delicate detail in the image. My most-used and favorite noise suppression is found in Photoshop CS 5 Camera Raw. If I cannot get the desired results with the first choice, I will use Noise Ninja, which has certain advantages in some situations that we will cover.

  20. Comparative study of adaptive-noise-cancellation algorithms for intrusion detection systems

    International Nuclear Information System (INIS)

    Claassen, J.P.; Patterson, M.M.

    1981-01-01

    Some intrusion detection systems are susceptible to nonstationary noise resulting in frequent nuisance alarms and poor detection when the noise is present. Adaptive inverse filtering for single channel systems and adaptive noise cancellation for two channel systems have both demonstrated good potential in removing correlated noise components prior detection. For such noise susceptible systems the suitability of a noise reduction algorithm must be established in a trade-off study weighing algorithm complexity against performance. The performance characteristics of several distinct classes of algorithms are established through comparative computer studies using real signals. The relative merits of the different algorithms are discussed in the light of the nature of intruder and noise signals

  1. Detection threshold for sound distortion resulting from noise reduction in normal-hearing and hearing-impaired listeners

    NARCIS (Netherlands)

    Brons, Inge; Dreschler, Wouter A.; Houben, Rolph

    2014-01-01

    Hearing-aid noise reduction should reduce background noise, but not disturb the target speech. This objective is difficult because noise reduction suffers from a trade-off between the amount of noise removed and signal distortion. It is unknown if this important trade-off differs between

  2. Aircrafts' taxi noise emission

    NARCIS (Netherlands)

    Asensio, C.; Pagan Munoz, Raul; López, J.M.

    2008-01-01

    An investigation has been conducted, with the objective of creating a database of inputs that can be used with noise prediction software, to evaluate noise of aircraft taxing movements and community noise exposure levels. The acoustic consultant can use these data with any of the software packages,

  3. A multi-stage noise adaptive switching filter for extremely corrupted images

    Science.gov (United States)

    Dinh, Hai; Adhami, Reza; Wang, Yi

    2015-07-01

    A multi-stage noise adaptive switching filter (MSNASF) is proposed for the restoration of images extremely corrupted by impulse and impulse-like noise. The filter consists of two steps: noise detection and noise removal. The proposed extrema-based noise detection scheme utilizes the false contouring effect to get better over detection rate at low noise density. It is adaptive and will detect not only impulse but also impulse-like noise. In the noise removal step, a novel multi-stage filtering scheme is proposed. It replaces corrupted pixel with the nearest uncorrupted median to preserve details. When compared with other methods, MSNASF provides better peak signal to noise ratio (PSNR) and structure similarity index (SSIM). A subjective evaluation carried out online also demonstrates that MSNASF yields higher fidelity.

  4. Near-source noise suppression of AMT by compressive sensing and mathematical morphology filtering

    Science.gov (United States)

    Li, Guang; Xiao, Xiao; Tang, Jing-Tian; Li, Jin; Zhu, Hui-Jie; Zhou, Cong; Yan, Fa-Bao

    2017-12-01

    In deep mineral exploration, the acquisition of audio magnetotelluric (AMT) data is severely affected by ambient noise near the observation sites; This near-field noise restricts investigation depths. Mathematical morphological filtering (MMF) proved effective in suppressing large-scale strong and variably shaped noise, typically low-frequency noise, but can not deal with pulse noise of AMT data. We combine compressive sensing and MMF. First, we use MMF to suppress the large-scale strong ambient noise; second, we use the improved orthogonal match pursuit (IOMP) algorithm to remove the residual pulse noise. To remove the noise and protect the useful AMT signal, a redundant dictionary that matches with spikes and is insensitive to the useful signal is designed. Synthetic and field data from the Luzong field suggest that the proposed method suppresses the near-source noise and preserves the signal well; thus, better results are obtained that improve the output of either MMF or IOMP.

  5. Microwave noise detection of a quantum dot with stub impedance matching

    OpenAIRE

    Hasler, Thomas

    2016-01-01

    Noise is defined as random fluctuations of a signal in time. The fundamental requirement for noise is some sort of randomness. Noise is well-known and infamous to every experimentalist - whether he is working in the field of electronics, optics, acoustics or anywhere else - since such fluctuations are inherent and unavoidable in many systems. For most of us, the word noise has a negative connotation. It is considered to be an unwanted disturbance superposed on a useful signal, which tend...

  6. Evaluation of adjunctive effect of low-level laser Therapy on pain, swelling and trismus after surgical removal of impacted lower third molar: A double blind randomized clinical trial.

    Science.gov (United States)

    Farhadi, Farrokh; Eslami, Hosein; Majidi, Alireza; Fakhrzadeh, Vahid; Ghanizadeh, Milad; KhademNeghad, Sahar

    2017-09-30

    Wisdom teeth remains impacted in the jaw due to several reasons and surgery of impacted wisdom teeth is one of the most common surgeries in dental clinics. Pain, swelling and trismus are the common complications after this surgery which affect quality of life. In articles, various methods are introduced to control immediate inflammatory-response associated with third-molar surgery. The aim of this study is to evaluate the adjunctive effect of low-level laser Therapy on pain, swelling and trismus after surgical removal of impacted lower third molar. This double-blind randomized controlled trial (RCT) was conducted on two groups of 24 patients (age range of 18-35) that had referred to surgical ward of Faculty of Dentistry, Tabriz University of Medical Sciences for surgery of their mandibular third molar(2015-16). All the subjects were systemically healthy and had at least one impacted mandibular third molar. After surgery, in experimental group, the laser was applied intraorally (inside the tooth socket) and extraorally (at the insertion point of the masseter muscle) immediately after surgery in contact with the target area for 25 seconds each. The laser energy was 2.5 J per area with an energy density of 5 J/ cm 2 at the surface of the probe (spot size= 0.5 cm 2 ). In the other group, as the control group, it was pretended to radiate. Trismus, pain, and swelling were evaluated on the first and seventh days after surgery. The obtained data were evaluated using SPSS 16 software and independent samples T-test. In the group where LLLT had been used, P> 0.05 was calculated for pain, swelling, and trismus on days 1 and 7 after surgery that was not statistically significant. Under limitations of this study, using low-power laser with mentioned parameters, clinically reduces pain, swelling and trismus after surgical removal of impacted mandibular wisdom, but not statistically significant.

  7. Lower tidal volume strategy (≈3 ml/kg) combined with extracorporeal CO2 removal versus 'conventional' protective ventilation (6 ml/kg) in severe ARDS: the prospective randomized Xtravent-study.

    Science.gov (United States)

    Bein, Thomas; Weber-Carstens, Steffen; Goldmann, Anton; Müller, Thomas; Staudinger, Thomas; Brederlau, Jörg; Muellenbach, Ralf; Dembinski, Rolf; Graf, Bernhard M; Wewalka, Marlene; Philipp, Alois; Wernecke, Klaus-Dieter; Lubnow, Matthias; Slutsky, Arthur S

    2013-05-01

    Acute respiratory distress syndrome is characterized by damage to the lung caused by various insults, including ventilation itself, and tidal hyperinflation can lead to ventilator induced lung injury (VILI). We investigated the effects of a low tidal volume (V(T)) strategy (V(T) ≈ 3 ml/kg/predicted body weight [PBW]) using pumpless extracorporeal lung assist in established ARDS. Seventy-nine patients were enrolled after a 'stabilization period' (24 h with optimized therapy and high PEEP). They were randomly assigned to receive a low V(T) ventilation (≈3 ml/kg) combined with extracorporeal CO2 elimination, or to a ARDSNet strategy (≈6 ml/kg) without the extracorporeal device. The primary outcome was the 28-days and 60-days ventilator-free days (VFD). Secondary outcome parameters were respiratory mechanics, gas exchange, analgesic/sedation use, complications and hospital mortality. Ventilation with very low V(T)'s was easy to implement with extracorporeal CO2-removal. VFD's within 60 days were not different between the study group (33.2 ± 20) and the control group (29.2 ± 21, p = 0.469), but in more hypoxemic patients (PaO2/FIO2 ≤150) a post hoc analysis demonstrated significant improved VFD-60 in study patients (40.9 ± 12.8) compared to control (28.2 ± 16.4, p = 0.033). The mortality rate was low (16.5%) and did not differ between groups. The use of very low V(T) combined with extracorporeal CO2 removal has the potential to further reduce VILI compared with a 'normal' lung protective management. Whether this strategy will improve survival in ARDS patients remains to be determined (Clinical trials NCT 00538928).

  8. Reduction of environmental MHz noise for SQUID application

    Energy Technology Data Exchange (ETDEWEB)

    Araya, T. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan)]. E-mail: araya@sup.ee.es.osaka-u.ac.jp; Kitamura, Y. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan); Kamishiro, M. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan); Sakuta, K. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan); Itozaki, H. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan)]. E-mail: itozaki@ee.es.osaka-u.ac.jp

    2006-10-01

    It is important to remove large environmental noise in measurement using SQUIDs without magnetic shielding. Active noise control (ANC) is an effective method to remove the environmental noise. The environmental noise has been reduced by the ANC system in the radio frequency region around MHz. The anti-phase waves of the environmental noise should be generated by this system. The ANC system including the phase and amplitude control circuit was developed to make the anti-phase waves in the MHz region. In this paper, sinusoidal waves with a MHz frequency were used as the environmental noise. When a coil antenna was used for a receiver antenna, this ANC system suppressed these sinusoidal waves to the white noise level about 40 dB. When we used a SQUID as a receiver antenna, we also cancelled sinusoidal waves to the white noise level by this system. This shows that the ANC system is useful to reduce an environmental noise when this ANC system is developed to cancel multi-frequency noise.

  9. Reduction of environmental MHz noise for SQUID application

    International Nuclear Information System (INIS)

    Araya, T.; Kitamura, Y.; Kamishiro, M.; Sakuta, K.; Itozaki, H.

    2006-01-01

    It is important to remove large environmental noise in measurement using SQUIDs without magnetic shielding. Active noise control (ANC) is an effective method to remove the environmental noise. The environmental noise has been reduced by the ANC system in the radio frequency region around MHz. The anti-phase waves of the environmental noise should be generated by this system. The ANC system including the phase and amplitude control circuit was developed to make the anti-phase waves in the MHz region. In this paper, sinusoidal waves with a MHz frequency were used as the environmental noise. When a coil antenna was used for a receiver antenna, this ANC system suppressed these sinusoidal waves to the white noise level about 40 dB. When we used a SQUID as a receiver antenna, we also cancelled sinusoidal waves to the white noise level by this system. This shows that the ANC system is useful to reduce an environmental noise when this ANC system is developed to cancel multi-frequency noise

  10. Classical noise, quantum noise and secure communication

    International Nuclear Information System (INIS)

    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. (review)

  11. Efficacy of Codeine When Added to Paracetamol (Acetaminophen) and Ibuprofen for Relief of Postoperative Pain After Surgical Removal of Impacted Third Molars: A Double-Blinded Randomized Control Trial.

    Science.gov (United States)

    Best, Adrian D; De Silva, R K; Thomson, W M; Tong, Darryl C; Cameron, Claire M; De Silva, Harsha L

    2017-10-01

    The use of opioids in combination with nonopioids is common practice for acute pain management after third molar surgery. One such combination is paracetamol, ibuprofen, and codeine. The authors assessed the efficacy of codeine when added to a regimen of paracetamol and ibuprofen for pain relief after third molar surgery. This study was a randomized, double-blinded, placebo-controlled trial conducted in patients undergoing the surgical removal of at least 1 impacted mandibular third molar requiring bone removal. Participants were randomly allocated to a control group (paracetamol 1,000 mg and ibuprofen 400 mg) or an intervention group (paracetamol 1,000 mg, ibuprofen 400 mg, and codeine 60 mg). All participants were treated under intravenous sedation and using identical surgical conditions and technique. Postoperative pain was assessed using the visual analog scale (VAS) every 3 hours (while awake) for the first 48 hours after surgery. Pain was globally assessed using a questionnaire on day 3 after surgery. There were 131 participants (36% men; control group, n = 67; intervention group, n = 64). Baseline characteristics were similar for the 2 groups. Data were analyzed using a modified intention-to-treat analysis and, for this, a linear mixed model was used. The model showed that the baseline VAS score was associated with subsequent VAS scores and that, with each 3-hour period, the VAS score increased by an average of 0.08. The treatment effect was not statistically meaningful, indicating there was no difference in recorded pain levels between the 2 groups during the first 48 hours after mandibular third molar surgery. Similarly, the 2 groups did not differ in their global ratings of postoperative pain. Codeine 60 mg added to a regimen of paracetamol 1,000 mg and ibuprofen 400 mg does not improve analgesia after third molar surgery. Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights

  12. 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.

  13. Combat aircraft noise

    Science.gov (United States)

    Sgarbozza, M.; Depitre, A.

    1992-04-01

    A discussion of the characteristics and the noise levels of combat aircraft and of a transport aircraft in taking off and landing are presented. Some methods of noise reduction are discussed, including the following: operational anti-noise procedures; and concepts of future engines (silent post-combustion and variable cycle). Some measurement results concerning the noise generated in flight at great speeds and low altitude will also be examined. Finally, the protection of the environment of French air bases against noise will be described and the possibilities of regulation examined.

  14. 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....

  15. Removing Bureaucracy

    Science.gov (United States)

    2015-08-01

    11 Defense AT&L: July–August 2015 Removing Bureaucracy Katharina G. McFarland McFarland is Assistant Secretary of Defense for Acquisition. I once...involvement from all of the Service warfighting areas came together to scrub the program requirements due to concern over the “ bureaucracy ” and... Bureaucracy ” that focuses on reducing cycle time, staffing time and all forms of inefficiencies. This includes review of those burdens that Congress

  16. On the Impact of Anomalous Noise Events on Road Traffic Noise Mapping in Urban and Suburban Environments.

    Science.gov (United States)

    Orga, Ferran; Alías, Francesc; Alsina-Pagès, Rosa Ma

    2017-12-23

    Noise pollution is a critical factor affecting public health, the relationship between road traffic noise (RTN) and several diseases in urban areas being especially disturbing. The Environmental Noise Directive 2002/49/EC and the CNOSSOS-EU framework are the main instruments of the European Union to identify and combat noise pollution, requiring Member States to compose and publish noise maps and noise management action plans every five years. Nowadays, the noise maps are starting to be tailored by means of Wireless Acoustic Sensor Networks (WASN). In order to exclusively monitor the impact of RTN on the well-being of citizens through WASN-based approaches, those noise sources unrelated to RTN denoted as Anomalous Noise Events (ANEs) should be removed from the noise map generation. This paper introduces an analysis methodology considering both Signal-to-Noise Ratio (SNR) and duration of ANEs to evaluate their impact on the A-weighted equivalent RTN level calculation for different integration times. The experiments conducted on 9 h of real-life data from the WASN-based DYNAMAP project show that both individual high-impact events and aggregated medium-impact events bias significantly the equivalent noise levels of the RTN map, making any derived study about public health impact inaccurate.

  17. Noise suppression in duct

    International Nuclear Information System (INIS)

    Ahmed, A.; Barfeh, M.A.G.

    2001-01-01

    In air-conditioning system the noise generated by supply fan is carried by conditioned air through the ductwork. The noise created in ductwork run may be transmission, regenerative and ductborne. Transmission noise is fan noise, regenerative noise is due to turbulence in flow and ductborne noise is the noise radiating from duct to surroundings. Some noise is attenuated in ducts also but if noise level is high then it needs to be attenuated. A simple mitre bend can attenuate-noise. This principle is extended to V and M-shape ducts with inside lining of fibreglass, which gave maximum attenuation of 77 dB and 62 dB respectively corresponding to 8 kHz frequency as compared to mitre, bend giving maximum 18 dB attenuation. Sound level meter measured sound levels with octave band filter and tests were conducted in anechoic room. A V-shape attenuator can be used at fan outlet and high frequency noise can be minimized greatly. (author)

  18. Digital random-number generator

    Science.gov (United States)

    Brocker, D. H.

    1973-01-01

    For binary digit array of N bits, use N noise sources to feed N nonlinear operators; each flip-flop in digit array is set by nonlinear operator to reflect whether amplitude of generator which feeds it is above or below mean value of generated noise. Fixed-point uniform distribution random number generation method can also be used to generate random numbers with other than uniform distribution.

  19. Active3 noise reduction

    International Nuclear Information System (INIS)

    Holzfuss, J.

    1996-01-01

    Noise reduction is a problem being encountered in a variety of applications, such as environmental noise cancellation, signal recovery and separation. Passive noise reduction is done with the help of absorbers. Active noise reduction includes the transmission of phase inverted signals for the cancellation. This paper is about a threefold active approach to noise reduction. It includes the separation of a combined source, which consists of both a noise and a signal part. With the help of interaction with the source by scanning it and recording its response, modeling as a nonlinear dynamical system is achieved. The analysis includes phase space analysis and global radial basis functions as tools for the prediction used in a subsequent cancellation procedure. Examples are given which include noise reduction of speech. copyright 1996 American Institute of Physics

  20. 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.

  1. Instrument Variables for Reducing Noise in Parallel MRI Reconstruction

    Directory of Open Access Journals (Sweden)

    Yuchou Chang

    2017-01-01

    Full Text Available Generalized autocalibrating partially parallel acquisition (GRAPPA has been a widely used parallel MRI technique. However, noise deteriorates the reconstructed image when reduction factor increases or even at low reduction factor for some noisy datasets. Noise, initially generated from scanner, propagates noise-related errors during fitting and interpolation procedures of GRAPPA to distort the final reconstructed image quality. The basic idea we proposed to improve GRAPPA is to remove noise from a system identification perspective. In this paper, we first analyze the GRAPPA noise problem from a noisy input-output system perspective; then, a new framework based on errors-in-variables (EIV model is developed for analyzing noise generation mechanism in GRAPPA and designing a concrete method—instrument variables (IV GRAPPA to remove noise. The proposed EIV framework provides possibilities that noiseless GRAPPA reconstruction could be achieved by existing methods that solve EIV problem other than IV method. Experimental results show that the proposed reconstruction algorithm can better remove the noise compared to the conventional GRAPPA, as validated with both of phantom and in vivo brain data.

  2. Lateralization of noise bursts in interaurally correlated or uncorrelated background noise using interaural level differences.

    Science.gov (United States)

    Reed, Darrin K; van de Par, Steven

    2015-10-01

    The interaural level difference (ILD) of a lateralized target source may be effectively reduced when the target is presented together with background noise containing zero ILD. It is not certain whether listeners perceive a position congruent with the reduced ILD or the actual target ILD in a lateralization task. Two sets of behavioral experiments revealed that many listeners perceived a position at or even larger than that corresponding to the presented target ILD when a temporal onset/offset asynchrony between the broadband target and the broadband background noise was present. When no temporal asynchrony was present, however, the perceived lateral position indicated a dependency on the coherence of the background noise for several listeners. With interaurally correlated background noise, listeners reported a reduced ILD resulting from the combined target and background noise stimulus. In contrast, several of the listeners made a reasonable estimate of the position corresponding to the target ILD for interaurally uncorrelated, broadband, background noise. No obvious difference in performance was seen between low- or high-frequency stimuli. Extension of a weighting template to the output of a standard equalization-cancellation model was shown to remove a lateral bias on the predicted target ILD resulting from the presence of background noise. Provided that an appropriate weighting template is applied based on knowledge of the background noise coherence, good prediction of the behavioral data is possible.

  3. 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

  4. Sensor response time monitoring using noise analysis

    International Nuclear Information System (INIS)

    Hashemian, H.M.; Thie, J.A.; Upadhyaya, B.R.; Holbert, K.E.

    1988-01-01

    Random noise techniques in nuclear power plants have been developed for system surveillance and for analysis of reactor core dynamics. The noise signals also contain information about sensor dynamics, and this can be extracted using frequency, amplitude and time domain analyses. Even though noise analysis has been used for sensor response time testing in some nuclear power plants, an adequate validation of this method has never been carried out. This paper presents the results of limited work recently performed to examine the validity of the noise analysis for sensor response time testing in nuclear power plants. The conclusion is that noise analysis has the potential for detecting gross changes in sensor response but it cannot be used for reliable measurement of response time until more laboratory and field experience is accumulated. The method is more advantageous for testing pressure sensors than it is for temperature sensors. This is because: 1) for temperature sensors, a method called Loop Current Step Response test is available which is quantitatively more exact than noise analysis, 2) no method currently exists for on-line testing of pressure transmitters other than the Power-Interrupt test which is applicable only to force balance pressure transmitters, and 3) pressure sensor response time is affected by sensing line degradation which is inherently taken into account by testing with noise analysis. (author)

  5. Judgments of aircraft noise in a traffic noise background

    Science.gov (United States)

    Powell, C. A.; Rice, C. G.

    1975-01-01

    An investigation was conducted to determine subjective response to aircraft noise in different road traffic backgrounds. In addition, two laboratory techniques for presenting the aircraft noise with the background noise were evaluated. For one technique, the background noise was continuous over an entire test session; for the other, the background noise level was changed with each aircraft noise during a session. Subjective response to aircraft noise was found to decrease with increasing background noise level, for a range of typical indoor noise levels. Subjective response was found to be highly correlated with the Noise Pollution Level (NPL) measurement scale.

  6. Digital signal processing for the Johnson noise thermometry: a time series analysis of the Johnson noise

    International Nuclear Information System (INIS)

    Moon, Byung Soo; Hwang, In Koo; Chung, Chong Eun; Kwon, Kee Choon; David, E. H.; Kisner, R.A.

    2004-06-01

    In this report, we first proved that a random signal obtained by taking the sum of a set of signal frequency signals generates a continuous Markov process. We used this random signal to simulate the Johnson noise and verified that the Johnson noise thermometry can be used to improve the measurements of the reactor coolant temperature within an accuracy of below 0.14%. Secondly, by using this random signal we determined the optimal sampling rate when the frequency band of the Johnson noise signal is given. Also the results of our examination on how good the linearity of the Johnson noise is and how large the relative error of the temperature could become when the temperature increases are described. Thirdly, the results of our analysis on a set of the Johnson noise signal blocks taken from a simple electric circuit are described. We showed that the properties of the continuous Markov process are satisfied even when some channel noises are present. Finally, we describe the algorithm we devised to handle the problem of the time lag in the long-term average or the moving average in a transient state. The algorithm is based on the Haar wavelet and is to estimate the transient temperature that has much smaller time delay. We have shown that the algorithm can track the transient temperature successfully

  7. Measurement time and statistics for a noise thermometer with a synthetic-noise reference

    Science.gov (United States)

    White, D. R.; Benz, S. P.; Labenski, J. R.; Nam, S. W.; Qu, J. F.; Rogalla, H.; Tew, W. L.

    2008-08-01

    This paper describes methods for reducing the statistical uncertainty in measurements made by noise thermometers using digital cross-correlators and, in particular, for thermometers using pseudo-random noise for the reference signal. First, a discrete-frequency expression for the correlation bandwidth for conventional noise thermometers is derived. It is shown how an alternative frequency-domain computation can be used to eliminate the spectral response of the correlator and increase the correlation bandwidth. The corresponding expressions for the uncertainty in the measurement of pseudo-random noise in the presence of uncorrelated thermal noise are then derived. The measurement uncertainty in this case is less than that for true thermal-noise measurements. For pseudo-random sources generating a frequency comb, an additional small reduction in uncertainty is possible, but at the cost of increasing the thermometer's sensitivity to non-linearity errors. A procedure is described for allocating integration times to further reduce the total uncertainty in temperature measurements. Finally, an important systematic error arising from the calculation of ratios of statistical variables is described.

  8. Trajectories of Brownian particles with space-correlated noise

    Indian Academy of Sciences (India)

    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 time and has a Gaussian correlation in space, and by means of numerical simulation, I show how the spatial correlation determines the time ...

  9. 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 ...

  10. Advanced digital signal processing and noise reduction

    CERN Document Server

    Vaseghi, Saeed V

    2008-01-01

    Digital signal processing plays a central role in the development of modern communication and information processing systems. The theory and application of signal processing is concerned with the identification, modelling and utilisation of patterns and structures in a signal process. The observation signals are often distorted, incomplete and noisy and therefore noise reduction, the removal of channel distortion, and replacement of lost samples are important parts of a signal processing system. The fourth edition of Advanced Digital Signal Processing and Noise Reduction updates an

  11. Milk removal

    OpenAIRE

    Ferneborg, Sabine

    2016-01-01

    Milk from dairy cows is a staple dietary component for humans all over the world. Regardless of whether milk is consumed in its purest, unaltered form or as high-end products such as fine cheese or ice cream, it needs to be of high quality when taken from the cow, produced at a low price and produced in a system that consider aspects such as animal health, animal welfare and sustainability. This thesis investigated the role of milk removal and the importance of residual milk on milk yield...

  12. assessment of noise pollutio noise pollutio noise pollution

    African Journals Online (AJOL)

    eobe

    re above the recommended limit of 85 dB(A) and these high noise intensit related health ... multiple workplaces i.e. steel pipe and a unit factory ... construction material. However .... selected workers, particularly the machine operators. In some ...

  13. Model tracking dual stochastic controller design under irregular internal noises

    International Nuclear Information System (INIS)

    Lee, Jong Bok; Heo, Hoon; Cho, Yun Hyun; Ji, Tae Young

    2006-01-01

    Although many methods about the control of irregular external noise have been introduced and implemented, it is still necessary to design a controller that will be more effective and efficient methods to exclude for various noises. Accumulation of errors due to model tracking, internal noises (thermal noise, shot noise and l/f noise) that come from elements such as resistor, diode and transistor etc. in the circuit system and numerical errors due to digital process often destabilize the system and reduce the system performance. New stochastic controller is adopted to remove those noises using conventional controller simultaneously. Design method of a model tracking dual controller is proposed to improve the stability of system while removing external and internal noises. In the study, design process of the model tracking dual stochastic controller is introduced that improves system performance and guarantees robustness under irregular internal noises which can be created internally. The model tracking dual stochastic controller utilizing F-P-K stochastic control technique developed earlier is implemented to reveal its performance via simulation

  14. 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.

  15. Adaptive noise cancellation

    International Nuclear Information System (INIS)

    Akram, N.

    1999-01-01

    In this report we describe the concept of adaptive noise canceling, an alternative method of estimating signals corrupted by additive noise of interference. The method uses 'primary' input containing the corrupted signal and a 'reference' input containing noise correlated in some unknown way with the primary noise, the reference input is adaptively filtered and subtracted from the primary input to obtain the signal estimate. Adaptive filtering before subtraction allows the treatment of inputs that are deterministic or stochastic, stationary or time variable. When the reference input is free of signal and certain other conditions are met then noise in the primary input can be essentially eliminated without signal distortion. It is further shown that the adaptive filter also acts as notch filter. Simulated results illustrate the usefulness of the adaptive noise canceling technique. (author)

  16. Visibility of wavelet quantization noise

    Science.gov (United States)

    Watson, A. B.; Yang, G. Y.; Solomon, J. A.; Villasenor, J.

    1997-01-01

    The discrete wavelet transform (DWT) decomposes an image into bands that vary in spatial frequency and orientation. It is widely used for image compression. Measures of the visibility of DWT quantization errors are required to achieve optimal compression. Uniform quantization of a single band of coefficients results in an artifact that we call DWT uniform quantization noise; it is the sum of a lattice of random amplitude basis functions of the corresponding DWT synthesis filter. We measured visual detection thresholds for samples of DWT uniform quantization noise in Y, Cb, and Cr color channels. The spatial frequency of a wavelet is r 2-lambda, where r is display visual resolution in pixels/degree, and lambda is the wavelet level. Thresholds increase rapidly with wavelet spatial frequency. Thresholds also increase from Y to Cr to Cb, and with orientation from lowpass to horizontal/vertical to diagonal. We construct a mathematical model for DWT noise detection thresholds that is a function of level, orientation, and display visual resolution. This allows calculation of a "perceptually lossless" quantization matrix for which all errors are in theory below the visual threshold. The model may also be used as the basis for adaptive quantization schemes.

  17. 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....

  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 subjec...... using running Danish and non-semantic speech materials as stimuli and modulated speech-spectrum and multi-talker babble noises as competing stimuli....

  20. Environmental noise pollution and risk of preeclampsia.

    Science.gov (United States)

    Auger, Nathalie; Duplaix, Mathilde; Bilodeau-Bertrand, Marianne; Lo, Ernest; Smargiassi, Audrey

    2018-08-01

    Environmental noise exposure is associated with a greater risk of hypertension, but the link with preeclampsia, a hypertensive disorder of pregnancy, is unclear. We sought to determine the relationship between environmental noise pollution and risk of preeclampsia during pregnancy. We analyzed a population-based cohort comprising 269,263 deliveries on the island of Montreal, Canada between 2000 and 2013. We obtained total environmental noise pollution measurements (LA eq24 , L den , L night ) from land use regression models, and assigned noise levels to each woman based on the residential postal code. We computed odds ratios (OR) and 95% confidence intervals (CI) for the association of noise with preeclampsia in mixed logistic regression models with participants as a random effect, and adjusted for air pollution, neighbourhood walkability, maternal age, parity, multiple pregnancy, comorbidity, socioeconomic deprivation, and year of delivery. We assessed whether noise exposure was more strongly associated with severe or early onset preeclampsia than mild or late onset preeclampsia. Prevalence of preeclampsia was higher for women exposed to elevated environmental noise pollution levels (LA eq24h  ≥ 65 dB(A) = 37.9 per 1000 vs. <50 dB(A) = 27.9 per 1000). Compared with 50 dB(A), an LA eq24h of 65.0 dB(A) was not significantly associated the risk of preeclampsia (OR 1.09, 95% CI 0.99-1.20). Associations were however present with severe (OR 1.29, 95% CI 1.09-1.54) and early onset (OR 1.71, 95% CI 1.20-2.43) preeclampsia, with results consistent across all noise indicators. The associations were much weaker or absent for mild and late preeclampsia. Environmental noise pollution may be a novel risk factor for pregnancy-related hypertension, particularly more severe variants of preeclampsia. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. Application of Machine Learning Algorithms to the Study of Noise Artifacts in Gravitational-Wave Data

    Science.gov (United States)

    Biswas, Rahul; Blackburn, Lindy L.; Cao, Junwei; Essick, Reed; Hodge, Kari Alison; Katsavounidis, Erotokritos; Kim, Kyungmin; Young-Min, Kim; Le Bigot, Eric-Olivier; Lee, Chang-Hwan; hide

    2014-01-01

    The sensitivity of searches for astrophysical transients in data from the Laser Interferometer Gravitationalwave Observatory (LIGO) is generally limited by the presence of transient, non-Gaussian noise artifacts, which occur at a high-enough rate such that accidental coincidence across multiple detectors is non-negligible. Furthermore, non-Gaussian noise artifacts typically dominate over the background contributed from stationary noise. These "glitches" can easily be confused for transient gravitational-wave signals, and their robust identification and removal will help any search for astrophysical gravitational-waves. We apply Machine Learning Algorithms (MLAs) to the problem, using data from auxiliary channels within the LIGO detectors that monitor degrees of freedom unaffected by astrophysical signals. Terrestrial noise sources may manifest characteristic disturbances in these auxiliary channels, inducing non-trivial correlations with glitches in the gravitational-wave data. The number of auxiliary-channel parameters describing these disturbances may also be extremely large; high dimensionality is an area where MLAs are particularly well-suited. We demonstrate the feasibility and applicability of three very different MLAs: Artificial Neural Networks, Support Vector Machines, and Random Forests. These classifiers identify and remove a substantial fraction of the glitches present in two very different data sets: four weeks of LIGO's fourth science run and one week of LIGO's sixth science run. We observe that all three algorithms agree on which events are glitches to within 10% for the sixth science run data, and support this by showing that the different optimization criteria used by each classifier generate the same decision surface, based on a likelihood-ratio statistic. Furthermore, we find that all classifiers obtain similar limiting performance, suggesting that most of the useful information currently contained in the auxiliary channel parameters we extract

  2. 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...

  3. Understanding jet noise.

    Science.gov (United States)

    Karabasov, S A

    2010-08-13

    Jets are one of the most fascinating topics in fluid mechanics. For aeronautics, turbulent jet-noise modelling is particularly challenging, not only because of the poor understanding of high Reynolds number turbulence, but also because of the extremely low acoustic efficiency of high-speed jets. Turbulent jet-noise models starting from the classical Lighthill acoustic analogy to state-of-the art models were considered. No attempt was made to present any complete overview of jet-noise theories. Instead, the aim was to emphasize the importance of sound generation and mean-flow propagation effects, as well as their interference, for the understanding and prediction of jet noise.

  4. 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.

  5. On randomly interrupted diffusion

    International Nuclear Information System (INIS)

    Luczka, J.

    1993-01-01

    Processes driven by randomly interrupted Gaussian white noise are considered. An evolution equation for single-event probability distributions in presented. Stationary states are considered as a solution of a second-order ordinary differential equation with two imposed conditions. A linear model is analyzed and its stationary distributions are explicitly given. (author). 10 refs

  6. Noise effect in metabolic networks

    International Nuclear Information System (INIS)

    Zheng-Yan, Li; Zheng-Wei, Xie; Tong, Chen; Qi, Ouyang

    2009-01-01

    Constraint-based models such as flux balance analysis (FBA) are a powerful tool to study biological metabolic networks. Under the hypothesis that cells operate at an optimal growth rate as the result of evolution and natural selection, this model successfully predicts most cellular behaviours in growth rate. However, the model ignores the fact that cells can change their cellular metabolic states during evolution, leaving optimal metabolic states unstable. Here, we consider all the cellular processes that change metabolic states into a single term 'noise', and assume that cells change metabolic states by randomly walking in feasible solution space. By simulating a state of a cell randomly walking in the constrained solution space of metabolic networks, we found that in a noisy environment cells in optimal states tend to travel away from these points. On considering the competition between the noise effect and the growth effect in cell evolution, we found that there exists a trade-off between these two effects. As a result, the population of the cells contains different cellular metabolic states, and the population growth rate is at suboptimal states. (cross-disciplinary physics and related areas of science and technology)

  7. Coherent diffractive imaging using randomly coded masks

    Energy Technology Data Exchange (ETDEWEB)

    Seaberg, Matthew H., E-mail: seaberg@slac.stanford.edu [CNRS and D.I., UMR 8548, École Normale Supérieure, 45 Rue d' Ulm, 75005 Paris (France); Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); D' Aspremont, Alexandre [CNRS and D.I., UMR 8548, École Normale Supérieure, 45 Rue d' Ulm, 75005 Paris (France); Turner, Joshua J. [Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States)

    2015-12-07

    We experimentally demonstrate an extension to coherent diffractive imaging that encodes additional information through the use of a series of randomly coded masks, removing the need for typical object-domain constraints while guaranteeing a unique solution to the phase retrieval problem. Phase retrieval is performed using a numerical convex relaxation routine known as “PhaseCut,” an iterative algorithm known for its stability and for its ability to find the global solution, which can be found efficiently and which is robust to noise. The experiment is performed using a laser diode at 532.2 nm, enabling rapid prototyping for future X-ray synchrotron and even free electron laser experiments.

  8. Principal component analysis of 1/fα noise

    International Nuclear Information System (INIS)

    Gao, J.B.; Cao Yinhe; Lee, J.-M.

    2003-01-01

    Principal component analysis (PCA) is a popular data analysis method. One of the motivations for using PCA in practice is to reduce the dimension of the original data by projecting the raw data onto a few dominant eigenvectors with large variance (energy). Due to the ubiquity of 1/f α noise in science and engineering, in this Letter we study the prototypical stochastic model for 1/f α processes--the fractional Brownian motion (fBm) processes using PCA, and find that the eigenvalues from PCA of fBm processes follow a power-law, with the exponent being the key parameter defining the fBm processes. We also study random-walk-type processes constructed from DNA sequences, and find that the eigenvalue spectrum from PCA of those random-walk processes also follow power-law relations, with the exponent characterizing the correlation structures of the DNA sequence. In fact, it is observed that PCA can automatically remove linear trends induced by patchiness in the DNA sequence, hence, PCA has a similar capability to the detrended fluctuation analysis. Implications of the power-law distributed eigenvalue spectrum are discussed

  9. Noise minimization in eukaryotic gene expression.

    Directory of Open Access Journals (Sweden)

    Hunter B Fraser

    2004-06-01

    Full Text Available 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.

  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 minimization in eukaryotic gene expression

    International Nuclear Information System (INIS)

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

    2004-01-01

    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

  12. Sounds and Noises. A Position Paper on Noise Pollution.

    Science.gov (United States)

    Chapman, Thomas L.

    This position paper focuses on noise pollution and the problems and solutions associated with this form of pollution. The paper is divided into the following five sections: Noise and the Ear, Noise Measurement, III Effects of Noise, Acoustics and Action, and Programs and Activities. The first section identifies noise and sound, the beginnings of…

  13. A Two-Sensor Noise Reduction System: Applications for Hands-Free Car Kit

    Directory of Open Access Journals (Sweden)

    Guérin Alexandre

    2003-01-01

    Full Text Available This paper presents a two-microphone speech enhancer designed to remove noise in hands-free car kits. The algorithm, based on the magnitude squared coherence, uses speech correlation and noise decorrelation to separate speech from noise. The remaining correlated noise is reduced using cross-spectral subtraction. Particular attention is focused on the estimation of the different spectral densities (noise and noisy signals power spectral densities which are critical for the quality of the algorithm. We also propose a continuous noise estimation, avoiding the need of vocal activity detector. Results on recorded signals are provided, showing the superiority of the two-sensor approach to single microphone techniques.

  14. 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.

  15. On the stochastic pendulum with Ornstein-Uhlenbeck noise

    International Nuclear Information System (INIS)

    Mallick, Kirone; Marcq, Philippe

    2004-01-01

    We study a frictionless pendulum subject to multiplicative random noise. Because of destructive interference between the angular displacement of the system and the noise term, the energy fluctuations are reduced when the noise has a non-zero correlation time. We derive the long time behaviour of the pendulum in the case of Ornstein-Uhlenbeck noise by a recursive adiabatic elimination procedure. An analytical expression for the asymptotic probability distribution function of the energy is obtained and the results agree with numerical simulations. Lastly, we compare our method with other approximation schemes

  16. Suitable or optimal noise benefits in signal detection

    International Nuclear Information System (INIS)

    Liu, Shujun; Yang, Ting; Tang, Mingchun; Wang, Pin; Zhang, Xinzheng

    2016-01-01

    Highlights: • Six intervals of additive noises divided according to the two constraints. • Derivation of the suitable additive noise to meet the two constraints. • Formulation of the suitable noise for improvability or nonimprovability. • Optimal noises to minimize P FA , maximize P D and maximize the overall improvement. - Abstract: We present an effective way to generate the suitable or the optimal additive noises which can achieve the three goals of the noise enhanced detectability, i.e., the maximum detection probability (P D ), the minimum false alarm probability (P FA ) and the maximum overall improvement of P D and P FA , without increasing P FA and decreasing P D in a binary hypothesis testing problem. The mechanism of our method is that we divide the discrete vectors into six intervals and choose the useful or partial useful vectors from these intervals to form the additive noise according to different requirements. The form of the optimal noise is derived and proven as a randomization of no more than two discrete vectors in our way. Moreover, how to choose suitable and optimal noises from the six intervals are given. Finally, numerous examples are presented to illustrate the theoretical analysis, where the background noises are Gaussian, symmetric and asymmetric Gaussian mixture noise, respectively.

  17. The equivalent internal orientation and position noise for contour integration.

    Science.gov (United States)

    Baldwin, Alex S; Fu, Minnie; Farivar, Reza; Hess, Robert F

    2017-10-12

    Contour integration is the joining-up of local responses to parts of a contour into a continuous percept. In typical studies observers detect contours formed of discrete wavelets, presented against a background of random wavelets. This measures performance for detecting contours in the limiting external noise that background provides. Our novel task measures contour integration without requiring any background noise. This allowed us to perform noise-masking experiments using orientation and position noise. From these we measure the equivalent internal noise for contour integration. We found an orientation noise of 6° and position noise of 3 arcmin. Orientation noise was 2.6x higher in contour integration compared to an orientation discrimination control task. Comparing against a position discrimination task found position noise in contours to be 2.4x lower. This suggests contour integration involves intermediate processing that enhances the quality of element position representation at the expense of element orientation. Efficiency relative to the ideal observer was lower for the contour tasks (36% in orientation noise, 21% in position noise) compared to the controls (54% and 57%).

  18. A statistical background noise correction sensitive to the steadiness of background noise.

    Science.gov (United States)

    Oppenheimer, Charles H

    2016-10-01

    A statistical background noise correction is developed for removing background noise contributions from measured source levels, producing a background noise-corrected source level. Like the standard background noise corrections of ISO 3741, ISO 3744, ISO 3745, and ISO 11201, the statistical background correction increases as the background level approaches the measured source level, decreasing the background noise-corrected source level. Unlike the standard corrections, the statistical background correction increases with steadiness of the background and is excluded from use when background fluctuation could be responsible for measured differences between the source and background noise levels. The statistical background noise correction has several advantages over the standard correction: (1) enveloping the true source with known confidence, (2) assuring physical source descriptions when measuring sources in fluctuating backgrounds, (3) reducing background corrected source descriptions by 1 to 8 dB for sources in steady backgrounds, and (4) providing a means to replace standardized background correction caps that incentivize against high precision grade methods.

  19. 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...

  20. Post commissioning noise study

    International Nuclear Information System (INIS)

    Heraud, P.

    2008-01-01

    This presentation described a wind farm post-commissioning study conducted at a wind farm owned by Helimax Energy Inc. The farm was located in a partly-forested, partly cultivated region in Quebec that featured gently rolling hills. Over 600 dwellings were located within 2 km of the wind farm, and 44 dwellings were within the wind farm's boundaries. The noise impact assessments were conducted at various points near the wind farm. The wind farm was designed using an International Standards Organization (ISO) noise propagation model and a 40 dBA to provide adequate setbacks. The study was conducted using 10 days of continuous measurements at selected points of a wind farm. Points of reception included points from 650 m to 800 m. Noise over 2 km was not thought to be contributed by the wind turbine. The nearest dwelling was 512 m from one of the farm's wind turbines. The study also considered ground factor, temperature, relative humidity, and the height of the receptors. Quebec noise level limits are 40 dBA at night, and 45 dBA during the day. Noise level limits are independent of wind speed. Measured noise contributions over 40 dBA were not observed during the measurement program. The wind turbines were only audible for 1 night out of the 30 night study period. It was concluded that the ISO noise propagation model is a reliable tool for conducting noise impact assessments. tabs., figs

  1. Noise, buildings and people

    Energy Technology Data Exchange (ETDEWEB)

    Croome, D J

    1977-01-01

    This book covers the physics of acoustics necessary to understand the analytical aspects of acoustical design and noise control in buildings. The major part is devoted to the problems of noise and man, and other chapters cover features of noise control in and around buildings. In an introduction, building environmental engineering is dealth with in general terms of architecture, creativity, systms design, etc. Aspects of the acoustical environment, noise sources in buildings, control of airborne and structure-borne noise and acoustical design techniques are covered in Part II. Items include: comfort, physiological response to noise and vibrations, noise criteria, human performance, speech communication, landscaped offices, sound generation by air-conditioning and heating equipment, building structure and noise attenuation, acoustical design. Part III gives some fundamentals of acoustics; mechanical vibration, wave motion, propagation of sound, structure-borne sound, behavior of sound in rooms, transmission of sound through structure. References include lists of British standards and booklets on health and safety at work.

  2. Low frequency noise study.

    Science.gov (United States)

    2007-04-01

    This report documents a study to investigate human response to the low-frequency : content of aviation noise, or low-frequency noise (LFN). The study comprised field : measurements and laboratory studies. The major findings were: : 1. Start-of-takeof...

  3. Noise Pollution, Teachers' Edition.

    Science.gov (United States)

    O'Donnell, Patrick A.; Lavaroni, Charles W.

    One of three in a series about pollution, this teacher's guide for a unit on noise pollution is designed for use in junior high school grades. It offers suggestions for extending the information and activities contained in the textual material for students. Chapter 1 discusses the problem of noise pollution and involves students in processes of…

  4. Discrete least squares polynomial approximation with random evaluations - application to PDEs with Random parameters

    KAUST Repository

    Nobile, Fabio

    2015-01-01

    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

  5. Absolute negative mobility induced by white Poissonian noise

    International Nuclear Information System (INIS)

    Spiechowicz, J; Łuczka, J; Hänggi, P

    2013-01-01

    We study the transport properties of inertial Brownian particles which move in a symmetric periodic potential and are subjected to both a symmetric, unbiased time-periodic external force and a biased Poissonian white shot noise (of non-zero average F) which is composed of a random sequence of δ-shaped pulses with random amplitudes. Upon varying the parameters of the white shot noise, one can conveniently manipulate the transport direction and the overall nonlinear response behavior. We find that within tailored parameter regimes the response is opposite to the applied average bias F of such white shot noise. This particular transport characteristic thus mimics that of a nonlinear absolute negative mobility (ANM) regime. Moreover, such white shot noise driven ANM is robust with respect to the statistics of the shot noise spikes. Our findings can be checked and corroborated experimentally by the use of a setup that consists of a single resistively and capacitively shunted Josephson junction device. (paper)

  6. Noise from wind turbines

    International Nuclear Information System (INIS)

    Andersen, B.; Larsen, P.

    1993-01-01

    Denmark has 3200 wind turbines with an installed maximum capacity of 418MW. The most important Danish research projects into wind turbine noise and the main results are listed. These date from 1983. Two comprehensive studies are currently in progress. The first is an analytical and empirical investigation of aerodynamic noise from wind turbine rotors and has so far dealt mainly with tip noise. The measurement method, using a hard board mounted microphone on the ground near the turbine, is described. Four different tip designs have been tested. Some examples of reference sound power level spectra for three of the designs are presented. During the past two years a computerbased data acquisition system has been used for real-time determination of sound power levels. The second study, which has just commenced, is on annoyance from wind turbine noise. It will include noise measurements, masking calculations and a social survey on the perceived nuisance. (UK)

  7. Noise from wind turbines

    International Nuclear Information System (INIS)

    Andersen, B.; Jakobsen, J.

    1992-11-01

    Based on a previous project concerning the calculation of the amount of noise emanating from wind turbine arrays, this one examines the subject further by investigating whether there could be significant differences in the amount of noise made by individual wind turbines in an array, and whether the noise is transmitted in varying directions - so that when it is carried in the same direction as the wind blows it would appear to be louder. The aim was also to determine whether the previously used method of calculation lacked precision. It was found that differences in noise niveaux related to individual wind turbines were insignificant and that noise was not so loud when it was not borne in the direction of the wind. It was necessary to change the method of calculation as reckoning should include the influence of the terrain, wind velocity and distance. The measuring and calculation methods are exemplified and the resulting measurements are presented in detail. (AB)

  8. Reactor noise monitoring device

    International Nuclear Information System (INIS)

    Yamanaka, Hiroto.

    1990-01-01

    The present invention concerns a reactor noise monitoring device by detecting abnormal sounds in background noises. Vibration sounds detected by accelerometers are applied to a loose parts detector. The detector generates high alarm if there are sudden impact sounds in the background noises and applies output signals to an accumulation device. If there is slight impact sounds in the vicinity of any of the accelerometers, the accumulation device accumulates the abnormal sounds assumed to be generated from an identical site while synchronizing the waveforms for all of the channels. Then, the device outputs signals in which the background noises are cancelled, as detection signals. Therefore, S/N ratio can be improved and the abnormal sounds contained in the background noises can be detected, to thereby improve the accuracy for estimating the position where the abnormal sounds are generated. (I.S.)

  9. 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

  10. 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

  11. Reducing noise in uranium exploration

    International Nuclear Information System (INIS)

    Ward, W.J. III.

    1977-01-01

    A method and apparatus are described for reducing or removing the background noise caused by thoron gas ( 220 Rn) in uranium exploration conducted by the detection of radon gas ( 222 Rn) emanating from the ground. This is accomplished by the use of a number of alpha particle detectors, each of which is disposed in a protective enclosure. A permselective membrane, which permits, but selectively retards, the passage therethrough of gases is disposed in the path to be traversed before such gases can reach the alpha particle detector. The retarding influence of the membrane should be sufficient to make the concentration of thoron inside the enclosure small relative to the concentration of thoron outside the enclosure. The influence of the membrane of radon should be negligible, i.e., the radon concentration inside and outside the enclosure should be substantially equal

  12. Slepian Simulations of Plastic Displacements of Randomly Excited Hysteretic Structures

    DEFF Research Database (Denmark)

    Lazarov, Boyan Stefanov

    2003-01-01

    The object of the study is a fast simulation method for generation and analysis of the plastic response of a randomly excited MDOF oscillatro with several potential elements with elasto-plastic constitutive behavior. The oscillator is statically determinate with linear damping. The external...... approximately as a stationary Gaussian process. This requires that the standard deviation of the stationary response is not too large as compared to the plastic yield limits. The Slepian model process for the behavior of the linear response is then simply the conditional mean (linear regression) of the process...... noise excited linear oscillator obtained from the elasto-plastic oscillator by totally removing the plastic domain. Thus the key to the applicability of the method is that the oscillator has a linear domain within which the response stays for a sufficiently long time to make the random response behave...

  13. Effect of noise in computed tomographic reconstructions on detectability

    International Nuclear Information System (INIS)

    Hanson, K.M.

    1982-01-01

    The detectability of features in an image is ultimately limited by the random fluctuations in density or noise present in that image. The noise in CT reconstructions arising from the statistical fluctuations in the one-dimensional input projection measurements has an unusual character owing to the reconstruction procedure. Such CT image noise differs from the white noise normally found in images in its lack of low-frequency components. The noise power spectrum of CT reconstructions can be related to the effective density of x-ray quanta detected in the projection measurements, designated as NEQ (noise-equivalent quanta). The detectability of objects that are somewhat larger than the spatial resolution is directly related to NEQ. Since contrast resolution may be defined in terms of the ability to detect large, low-contrast objects, the measurement of a CT scanner's NEQ may be used to characterize its contrast sensitivity

  14. 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.

  15. Noise and Hearing Loss Prevention

    Science.gov (United States)

    ... message, please visit this page: About CDC.gov . NOISE AND HEARING LOSS PREVENTION Language: English (US) Español ( ... when hazardous noise levels cannot be adequately reduced. Noise and Hearing Loss on the NIOSH Science Blog ...

  16. Feasibility of Johnson Noise Thermometry based on Digital Signal Processing Techniques

    International Nuclear Information System (INIS)

    Hwang, In Koo; Kim, Yang Mo

    2014-01-01

    This paper presents an implementation strategy of noise thermometry based on a digital signal processing technique and demonstrates its feasibilities. A key factor in its development is how to extract the small thermal noise signal from other noises, for example, random noise from amplifiers and continuous electromagnetic interference from the environment. The proposed system consists of two identical amplifiers and uses a cross correlation function to cancel the random noise of the amplifiers. Then, the external interference noises are eliminated by discriminating the difference in the peaks between the thermal signal and external noise. The gain of the amplifiers is estimated by injecting an already known pilot signal. The experimental simulation results of signal processing methods have demonstrated that the proposed approach is an effective method in eliminating an external noise signal and performing gain correction for development of the thermometry

  17. Handbook Of Noise And Vibration

    International Nuclear Information System (INIS)

    1995-12-01

    This book is about noise and vibration. The first chapter has explanations of noise such as basic of sound, influence of noise, assessment of noise, measurement of prevention of noise and technology, case of noise measurement and soundproof. The second chapter describes vibration with outline, theory of vibration, interpretation of vibration, measurement for reduction of vibration, case of design of protection against vibration. It deals with related regulation and method of measurement.

  18. Noise properties of Pb/Cd-free thick film resistors

    International Nuclear Information System (INIS)

    Stadler, Adam Witold; Kolek, Andrzej; Zawislak, Zbigniew; Mleczko, Krzysztof; Jakubowska, Malgorzata; Kielbasinski, Konrad Rafal; Mlozniak, Anna

    2010-01-01

    Low-frequency noise spectroscopy has been used to examine noise properties of Pb/Cd-free RuO 2 - and CaRuO 3 -based thick films screen printed on alumina substrates. Experiments were performed in the temperature range 77-300 K and the frequency range 0.5-5000 Hz with multiterminal devices. The measured noise has been recognized as resistance noise that consists of background 1/f noise and components generated by several thermally activated noise sources (TANSs) of different activation energies. The total noise has been composed of the contributions generated in the resistive layer and in the resistive/conductive layers interface. These noise sources are non-uniformly distributed in the resistor volume. Noise intensity of new-resistive layers has been described by the noise parameter C bulk . Pb/Cd-free layers turned out to be noisier than their Pb-containing counterparts; however, the removal of Pb and Cd from resistive composition is hardly responsible for the increase in the noise. In the case of RuO 2 layers noise increases most likely due to larger grain size of RuO 2 powder used to prepare resistive pastes. Information on the quality of the resistive-to-conductive layers interface occurred to be stored in the values of noise parameter C int . Pb/Cd-free RuO 2 -based resistive pastes form well-behaved interfaces with various Ag-based conductive pastes. In contrast, CaRuO 3 -based paste forms bad contacts with AgPd terminations because the density of TANSs increases in the interface area.

  19. Introductory guide to noise

    CSIR Research Space (South Africa)

    Ferreira, T.M

    1973-01-01

    Full Text Available or (by remaining at the 'alarm' level) prevents us from sleeping or resting. Some noise comes into buildings from outside, such as when a passing jet plane drowns a telephone conversation or when traffic noise prevents one from hearing an interesting... 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...

  20. 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.

  1. Hypermedicalization in White Noise.

    Science.gov (United States)

    Benson, Josef

    2015-09-01

    The Nazis hijacked Germany's medical establishment and appropriated medical language to hegemonize their ideology. In White Noise, shifting medical information stifles the public into docility. In Nazi Germany the primacy of language and medical authority magnified the importance of academic doctors. The muddling of identities caused complex insecurities and the need for psychological doubles. In White Noise, Professor Gladney is driven by professional insecurities to enact a double in Murray. Through the manipulation of language and medical overreach the U.S., exemplified in the novel White Noise, has become a hypermedicalized society where the spirit of the Hippocratic Oath has eroded.

  2. Controlled Noise Seismology

    KAUST Repository

    Hanafy, Sherif M.; AlTheyab, Abdullah; Schuster, Gerard T.

    2015-01-01

    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.

  3. NASVD and MNF techniques and your application noise reduction in gamma-ray spectrometric data; As tecnicas NASVD e MNF e sua aplicacao na reducao de ruidos em dados gamaespectrometricos

    Energy Technology Data Exchange (ETDEWEB)

    Cavallaro, Francisco de Assis, E-mail: assisfc@yahoo.com.br, E-mail: assis@agp-la.org [Departamento de Geologia Sedimentar e Ambiental, DGSA, Instituto de Geociencias, IG, Universidade de Sao Paulo, SP (Brazil); AGPLA, AeroGeoPhysica Latinoamerica, Sao Paulo, SP (Brazil); Portugal, Rodrigo S.; Bizuti, Ariathemis M., E-mail: portugal@ige.unicamp.br, E-mail: ambizuti@ige.unicamp.br [Departamento de Geologia e Recursos Naturais, DGRN, Instituto de Geociencias, IG, Universidade Estadual de Campinas, SP (Brazil); Silva, Adalene M., E-mail: adalene@unb.br [Universidade de Brasilia (UnB), DF (Brazil). Inst. de Geociencias. Dept. de Geoquimica e Recursos Minerais (GRM)

    2009-04-15

    The radioactive decay is a random process, and the measurement precision is ruled by statistical laws. The counting ratios of the profiles are always noisy when analyzed for short periods, such as one second per measurement. Corrections made at the end of conventional processing in the airborne gamma-ray spectrometric method data are not enough to remove and minimize, or even reduce considerably, the spectrum's originated noise. Two statistic methods that act locally in collected data, in the spectrum domain, have been suggested by literature to remove such remaining noises, the Noise-Adjusted Singular Value Decomposition - NASVD and Maximum Noise Fraction - MNF. These methods produce a significantly noise reduction. In this work both methods were applied in an area comprehended by two blocks, I and II, of the airborne survey that covers the west area of Mineral Province of Tapajos between Para and Amazon states. The filtered and non-filtered data with the NASVD and MNF techniques were processed with the Lasa's parameters. The comparison of results between maps and profiles shows that both methods are valuable, since there was resolution gain in these products. (author)

  4. On-line adaptive line frequency noise cancellation from a nuclear power measuring channel

    Directory of Open Access Journals (Sweden)

    Qadir Javed

    2011-01-01

    Full Text Available On-line software for adaptively canceling 50 Hz line frequency noise has been designed and tested at Pakistan Research Reactor 1. Line frequency noise causes much problem in weak signals acquisition. Sometimes this noise is so dominant that original signal is totally corrupted. Although notch filter can be used for eliminating this noise, but if signal of interest is in close vicinity of 50 Hz, then original signal is also attenuated and hence overall performance is degraded. Adaptive noise removal is a technique which could be employed for removing line frequency without degrading the desired signal. In this paper line frequency noise has been eliminated on-line from a nuclear power measuring channel. The adaptive LMS algorithm has been used to cancel 50 Hz noise. The algorithm has been implemented in labVIEW with NI 6024 data acquisition card. The quality of the acquired signal has been improved much as can be seen in experimental results.

  5. White Gaussian Noise - Models for Engineers

    Science.gov (United States)

    Jondral, Friedrich K.

    2018-04-01

    This paper assembles some information about white Gaussian noise (WGN) and its applications. It starts from a description of thermal noise, i. e. the irregular motion of free charge carriers in electronic devices. In a second step, mathematical models of WGN processes and their most important parameters, especially autocorrelation functions and power spectrum densities, are introduced. In order to proceed from mathematical models to simulations, we discuss the generation of normally distributed random numbers. The signal-to-noise ratio as the most important quality measure used in communications, control or measurement technology is accurately introduced. As a practical application of WGN, the transmission of quadrature amplitude modulated (QAM) signals over additive WGN channels together with the optimum maximum likelihood (ML) detector is considered in a demonstrative and intuitive way.

  6. Fast image interpolation via random forests.

    Science.gov (United States)

    Huang, Jun-Jie; Siu, Wan-Chi; Liu, Tian-Rui

    2015-10-01

    This paper proposes a two-stage framework for fast image interpolation via random forests (FIRF). The proposed FIRF method gives high accuracy, as well as requires low computation. The underlying idea of this proposed work is to apply random forests to classify the natural image patch space into numerous subspaces and learn a linear regression model for each subspace to map the low-resolution image patch to high-resolution image patch. The FIRF framework consists of two stages. Stage 1 of the framework removes most of the ringing and aliasing artifacts in the initial bicubic interpolated image, while Stage 2 further refines the Stage 1 interpolated image. By varying the number of decision trees in the random forests and the number of stages applied, the proposed FIRF method can realize computationally scalable image interpolation. Extensive experimental results show that the proposed FIRF(3, 2) method achieves more than 0.3 dB improvement in peak signal-to-noise ratio over the state-of-the-art nonlocal autoregressive modeling (NARM) method. Moreover, the proposed FIRF(1, 1) obtains similar or better results as NARM while only takes its 0.3% computational time.

  7. 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

  8. 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...

  9. Alien Noise Cancellation

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Full FEXT Cancellation. Expectation Maximization based Algorithms. Partial Cancellation. Optimal Choice of what to Cancel and what not to! Alien Noise Cancellation. Efficient Crosstalk channel estimation. In addition:

  10. Induced Noise Control

    National Research Council Canada - National Science Library

    Maidanik, G

    2002-01-01

    The induced noise control parameter is defined in terms of the ratio of the stored energy in a master dynamic system, when it is coupled to an adjunct dynamic system, to that stored energy when the coupling is absent...

  11. Quantum random number generator

    Science.gov (United States)

    Soubusta, Jan; Haderka, Ondrej; Hendrych, Martin

    2001-03-01

    Since reflection or transmission of a quantum particle on a beamsplitter is inherently random quantum process, a device built on this principle does not suffer from drawbacks of neither pseudo-random computer generators or classical noise sources. Nevertheless, a number of physical conditions necessary for high quality random numbers generation must be satisfied. Luckily, in quantum optics realization they can be well controlled. We present an easy random number generator based on the division of weak light pulses on a beamsplitter. The randomness of the generated bit stream is supported by passing the data through series of 15 statistical test. The device generates at a rate of 109.7 kbit/s.

  12. Impulse Noise Cancellation of Medical Images Using Wavelet Networks and Median Filters

    Science.gov (United States)

    Sadri, Amir Reza; Zekri, Maryam; Sadri, Saeid; Gheissari, Niloofar

    2012-01-01

    This paper presents a new two-stage approach to impulse noise removal for medical images based on wavelet network (WN). The first step is noise detection, in which the so-called gray-level difference and average background difference are considered as the inputs of a WN. Wavelet Network is used as a preprocessing for the second stage. The second step is removing impulse noise with a median filter. The wavelet network presented here is a fixed one without learning. Experimental results show that our method acts on impulse noise effectively, and at the same time preserves chromaticity and image details very well. PMID:23493998

  13. Film grain noise modeling in advanced video coding

    Science.gov (United States)

    Oh, Byung Tae; Kuo, C.-C. Jay; Sun, Shijun; Lei, Shawmin

    2007-01-01

    A new technique for film grain noise extraction, modeling and synthesis is proposed and applied to the coding of high definition video in this work. The film grain noise is viewed as a part of artistic presentation by people in the movie industry. On one hand, since the film grain noise can boost the natural appearance of pictures in high definition video, it should be preserved in high-fidelity video processing systems. On the other hand, video coding with film grain noise is expensive. It is desirable to extract film grain noise from the input video as a pre-processing step at the encoder and re-synthesize the film grain noise and add it back to the decoded video as a post-processing step at the decoder. Under this framework, the coding gain of the denoised video is higher while the quality of the final reconstructed video can still be well preserved. Following this idea, we present a method to remove film grain noise from image/video without distorting its original content. Besides, we describe a parametric model containing a small set of parameters to represent the extracted film grain noise. The proposed model generates the film grain noise that is close to the real one in terms of power spectral density and cross-channel spectral correlation. Experimental results are shown to demonstrate the efficiency of the proposed scheme.

  14. Core Noise Diagnostics of Turbofan Engine Noise Using Correlation and Coherence Functions

    Science.gov (United States)

    Miles, Jeffrey H.

    2009-01-01

    Cross-correlation and coherence functions are used to look for periodic acoustic components in turbofan engine combustor time histories, to investigate direct and indirect combustion noise source separation based on signal propagation time delays, and to provide information on combustor acoustics. Using the cross-correlation function, time delays were identified in all cases, clearly indicating the combustor is the source of the noise. In addition, unfiltered and low-pass filtered at 400 Hz signals had a cross-correlation time delay near 90 ms, while the low-pass filtered at less than 400 Hz signals had a cross-correlation time delay longer than 90 ms. Low-pass filtering at frequencies less than 400 Hz partially removes the direct combustion noise signals. The remainder includes the indirect combustion noise signal, which travels more slowly because of the dependence on the entropy convection velocity in the combustor. Source separation of direct and indirect combustion noise is demonstrated by proper use of low-pass filters with the cross-correlation function for a range of operating conditions. The results may lead to a better idea about the acoustics in the combustor and may help develop and validate improved reduced-order physics-based methods for predicting direct and indirect combustion noise.

  15. Noise frame duration, masking potency and whiteness of temporal noise.

    Science.gov (United States)

    Kukkonen, Heljä; Rovamo, Jyrki; Donner, Kristian; Tammikallio, Marja; Raninen, Antti

    2002-09-01

    Because of the limited contrast range, increasing the duration of the noise frame is often the only option for increasing the masking potency of external, white temporal noise. This, however, reduces the high-frequency cutoff beyond which noise is no longer white. This study was conducted to determine the longest noise frame duration that produces the strongest masking effect and still mimics white noise on the detection of sinusoidal flicker. Contrast energy thresholds (E(th)) were measured for flicker at 1.25 to 20 Hz in strong, purely temporal (spatially uniform), additive, external noise. The masking power of white external noise, characterized by its spectral density at zero frequency N0, increases with the duration of the noise frame. For short noise frame durations, E(th) increased in direct proportion to N0, keeping the nominal signal-to-noise ratio [SNR = (E(th)/N0)(0.5)] constant at threshold. The masking effect thus increased with the duration of the noise frame and the noise mimicked white noise. When noise frame duration and N0 increased further, the nominal SNR at threshold started to decrease, indicating that noise no longer mimicked white noise. The minimum number of noise frames per flicker cycle needed to mimic white noise decreased with increasing flicker frequency from 8.3 at 1.25 Hz to 1.6 at 20 Hz. The critical high-frequency cutoff of detection-limiting temporal noise in terms of noise frames per signal cycle depends on the temporal frequency of the signal. This is opposite to the situation in the spatial domain and must be taken into consideration when temporal signals are masked with temporal noise.

  16. 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...

  17. Power reactor noise

    International Nuclear Information System (INIS)

    Thie, J.A.

    1981-01-01

    This book concentrates on the different types of noise present in power reactors and how the analysis of this noise can be used as a tool for reactor monitoring and diagnostics. Noise analysis is a growing field that offers advantages such as simplicity, low cost, and natural multivariable interactions. A major advantage, continuous and undisturbed monitoring, supplies a means of obtaining early warnings of possible reactor malfunctions thus preventing further complications by alerting operators to a problem - and aiding in the diagnosis of that problem - before it demands major repairs. Following an introductory chapter, the theoretical basis for the various methods of noise analysis is explained, and full chapters are devoted to the fundamentals of statistics for time-domain analysis and Fourier series and related topics for frequency-domain analysis. General experimental techniques and associated theoretical considerations are reviewed, leading to discussion of practical applications in the latter half of the book. Besides chapters giving examples of neutron noise and acoustical noise, chapters are also devoted to extensive examples from pressurized water reactor and boiling water reactor power plants

  18. Improved Denoising via Poisson Mixture Modeling of Image Sensor Noise.

    Science.gov (United States)

    Zhang, Jiachao; Hirakawa, Keigo

    2017-04-01

    This paper describes a study aimed at comparing the real image sensor noise distribution to the models of noise often assumed in image denoising designs. A quantile analysis in pixel, wavelet transform, and variance stabilization domains reveal that the tails of Poisson, signal-dependent Gaussian, and Poisson-Gaussian models are too short to capture real sensor noise behavior. A new Poisson mixture noise model is proposed to correct the mismatch of tail behavior. Based on the fact that noise model mismatch results in image denoising that undersmoothes real sensor data, we propose a mixture of Poisson denoising method to remove the denoising artifacts without affecting image details, such as edge and textures. Experiments with real sensor data verify that denoising for real image sensor data is indeed improved by this new technique.

  19. Why nature needs 1/f noise

    International Nuclear Information System (INIS)

    Kuzovlev, Yu E

    2015-01-01

    While ubiquitous at all levels of organization in nature, including in nanotechnology, low-frequency 1/f noise is not yet understood. A possible reason is the unjustified application of probability theory concepts, primarily that of independence, to random physical phenomena. We show that in the framework of statistical mechanics, no medium can impart a definite diffusivity and mobility to a particle that performs random walk through it, which gives rise to flicker fluctuations in these properties. A universal source of 1/f noise in many-particle systems in this example is a dependence of the time behavior of any particular relaxation or transport process on the details of the initial microstate of the system as a whole. (methodological notes)

  20. 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.

  1. Noise reduction methods for nucleic acid and macromolecule sequencing

    Science.gov (United States)

    Schuller, Ivan K.; Di Ventra, Massimiliano; Balatsky, Alexander

    2018-05-08

    Methods, systems, and devices are disclosed for processing macromolecule sequencing data with substantial noise reduction. In one aspect, a method for reducing noise in a sequential measurement of a macromolecule comprising serial subunits includes cross-correlating multiple measured signals of a physical property of subunits of interest of the macromolecule, the multiple measured signals including the time data associated with the measurement of the signal, to remove or at least reduce signal noise that is not in the same frequency and in phase with the systematic signal contribution of the measured signals.

  2. 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....

  3. 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.

  4. Environmental noise in downtown Medellin 2002

    International Nuclear Information System (INIS)

    Bedoya, Julian; Correa E, Alexander

    2003-01-01

    A total of 6400 noise measurements were taken in downtown Medellin, a 2km x 2km area to characterize noise levels. The area was divided into a grid of 160 blocks with a length 154 m each; 40 measurements were taken in each block Sampling was conducted for 10 days, with simultaneous measurements in four sampling zones selected randomly and with coverage of four sampling periods 7:00-9:00 AM, 9:30-11:30 AM, 12:00 AM-2:00 PM, y 5:00-7:00 PM). The zone between 44 and 49 streets and between 40 and 49 avenues has the maximum average noise level with 74 dBA (decibels in scale A). Four of the noisiest sites were measured during 48 hours continuously by usage of a dosimeter Auto correlation results allowed use of Geo statistics to built isophones for the tour time periods. Isophones plots over imposed on physical layout of the city shows a good correlation between high noise levels and heavy traffic through main avenues (Avenida Oriental, Calle San Juan, Avenida del Ferrocarril, Bazar de los Puentes, Glorieta de la Minorista). Medellin is a noisy city that does not meet existing national regulations. The proposed methodology based on Geo statistics and experimental design is a feasible and comprehensive approach to manage urban noise

  5. Group-velocity dispersion effects on quantum noise of a fiber optical soliton in phase space

    International Nuclear Information System (INIS)

    Ju, Heongkyu; Lee, Euncheol

    2010-01-01

    Group-velocity dispersion (GVD) effects on quantum noise of ultrashort pulsed light are theoretically investigated at the soliton energy level, using Gaussian-weighted pseudo-random distribution of phasors in phase space for the modeling of quantum noise properties including phase noise, photon number noise, and quantum noise shape in phase space. We present the effects of GVD that mixes the different spectral components in time, on the self-phase modulation(SPM)-induced quantum noise properties in phase space such as quadrature squeezing, photon-number noise, and tilting/distortion of quantum noise shape in phase space, for the soliton that propagates a distance of the nonlinear length η NL = 1/( γP 0 ) (P 0 is the pulse peak power and γ is the SPM parameter). The propagation dependence of phase space quantum noise properties for an optical soliton is also provided.

  6. Stochastic Evolution Equations Driven by Fractional Noises

    Science.gov (United States)

    2016-11-28

    paper is to establish the weak convergence, in the topology of the Skorohod space, of the ν-symmetric Riemann sums for functionals of the fractional...stochastic heat equation with fractional-colored noise: existence of the solution. ALEA Lat. Am. J. Probab. Math . Stat. 4 (2008), 57–87. [8] P. Carmona, Y...Hu: Strong disorder implies strong localization for directed polymers in a random environment. ALEA Lat. Am. J. Probab. Math . Stat. 2 (2006), 217

  7. Noise frame duration, masking potency and whiteness of temporal noise

    OpenAIRE

    Kukkonen, Helja; Rovamo, Jyrki; Donner, Kristian; Tammikallio, Marja; Raninen, Antii

    2002-01-01

    PURPOSE. Because of the limited contrast range, increasing the duration of the noise frame is often the only option for increasing the masking potency of external, white temporal noise. This, however, reduces the high-frequency cutoff beyond which noise is no longer white. This study was conducted to determine the longest noise frame duration that produces the strongest masking effect and still mimics white noise on the detection of sinusoidal flicker. \\ud \\ud METHODS. Contrast energy thresho...

  8. Prediction of Landing Gear Noise Reduction and Comparison to Measurements

    Science.gov (United States)

    Lopes, Leonard V.

    2010-01-01

    Noise continues to be an ongoing problem for existing aircraft in flight and is projected to be a concern for next generation designs. During landing, when the engines are operating at reduced power, the noise from the airframe, of which landing gear noise is an important part, is equal to the engine noise. There are several methods of predicting landing gear noise, but none have been applied to predict the change in noise due to a change in landing gear design. The current effort uses the Landing Gear Model and Acoustic Prediction (LGMAP) code, developed at The Pennsylvania State University to predict the noise from landing gear. These predictions include the influence of noise reduction concepts on the landing gear noise. LGMAP is compared to wind tunnel experiments of a 6.3%-scale Boeing 777 main gear performed in the Quiet Flow Facility (QFF) at NASA Langley. The geometries tested in the QFF include the landing gear with and without a toboggan fairing and the door. It is shown that LGMAP is able to predict the noise directives and spectra from the model-scale test for the baseline configuration as accurately as current gear prediction methods. However, LGMAP is also able to predict the difference in noise caused by the toboggan fairing and by removing the landing gear door. LGMAP is also compared to far-field ground-based flush-mounted microphone measurements from the 2005 Quiet Technology Demonstrator 2 (QTD 2) flight test. These comparisons include a Boeing 777-300ER with and without a toboggan fairing that demonstrate that LGMAP can be applied to full-scale flyover measurements. LGMAP predictions of the noise generated by the nose gear on the main gear measurements are also shown.

  9. 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

  10. Generalised shot noise Cox processes

    DEFF Research Database (Denmark)

    Møller, Jesper; Torrisi, Giovanni Luca

    2005-01-01

    We introduce a class of cox cluster processes called generalised shot noise Cox processes (GSNCPs), which extends the definition of shot noise Cox processes (SNCPs) in two directions: the point process that drives the shot noise is not necessarily Poisson, and the kernel of the shot noise can...

  11. Pentek metal coating removal system: Baseline report

    International Nuclear Information System (INIS)

    1997-01-01

    The Pentek coating removal technology was tested and is being evaluated at Florida International University (FIU) as a baseline technology. In conjunction with FIU's evaluation of efficiency and cost, this report covers evaluation conducted for safety and health issues. It is a commercially available technology and has been used for various projects at locations throughout the country. The Pentek coating removal system consisted of the ROTO-PEEN Scaler, CORNER-CUTTER reg-sign, and VAC-PAC reg-sign. They are designed to remove coatings from steel, concrete, brick, and wood. The Scaler uses 3M Roto Peen tungsten carbide cutters while the CORNER-CUTTER reg-sign uses solid needles for descaling activities. These hand tools are used with the VAC-PAC reg-sign vacuum system to capture dust and debris as removal of the coating takes place. The safety and health evaluation during the testing demonstration focused on two main areas of exposure: dust and noise. Dust exposure minimal, but noise exposure was significant. Further testing for each exposure is recommended because of the environment where the testing demonstration took place. It is feasible that the dust and noise levels will be higher in an enclosed operating environment of different construction. In addition, other areas of concern found were arm-hand vibration, whole-body, ergonomics, heat stress, tripping hazards, electrical hazards, machine guarding, and lockout/tagout

  12. 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....

  13. Incoherent dictionary learning for reducing crosstalk noise in least-squares reverse time migration

    Science.gov (United States)

    Wu, Juan; Bai, Min

    2018-05-01

    We propose to apply a novel incoherent dictionary learning (IDL) algorithm for regularizing the least-squares inversion in seismic imaging. The IDL is proposed to overcome the drawback of traditional dictionary learning algorithm in losing partial texture information. Firstly, the noisy image is divided into overlapped image patches, and some random patches are extracted for dictionary learning. Then, we apply the IDL technology to minimize the coherency between atoms during dictionary learning. Finally, the sparse representation problem is solved by a sparse coding algorithm, and image is restored by those sparse coefficients. By reducing the correlation among atoms, it is possible to preserve most of the small-scale features in the image while removing much of the long-wavelength noise. The application of the IDL method to regularization of seismic images from least-squares reverse time migration shows successful performance.

  14. Noise equivalent count measurements in a neuro-PET scanner with retractable septa

    International Nuclear Information System (INIS)

    Bailey, D.L.; Jones, T.; Spinks, T.J.; Gilardi, M.C.; Townsend, D.W.

    1990-01-01

    This paper reports on the removal of interplane septa in a PET scanner that enables acquisition of all possible lines of response (3D mode) in an effort to maximize the available number of detected events. One problem with this method at high countrates, however, is a markedly increased deadtime and randoms rate, which has a deleterious effect on data quality. The noise-equivalent countrate (NEC) performance of a neuro-PET scanner has been determined with and without interplane septa on uniform cylindrical phantoms of differing radii and in human studies to assess the optimum countrate conditions that realize the maximum gain. In the brain, the effective gain in NEC performance for 3D ranges from >5 at low countrates to ∼3.3 at 200 kcps (equivalent to 37 kcps in 2D). The gains of the 3D method assessed by this analysis are significant, and are shown to be highly dependent on countrate and object dimensions

  15. Disk Density Tuning of a Maximal Random Packing.

    Science.gov (United States)

    Ebeida, Mohamed S; Rushdi, Ahmad A; Awad, Muhammad A; Mahmoud, Ahmed H; Yan, Dong-Ming; English, Shawn A; Owens, John D; Bajaj, Chandrajit L; Mitchell, Scott A

    2016-08-01

    We introduce an algorithmic framework for tuning the spatial density of disks in a maximal random packing, without changing the sizing function or radii of disks. Starting from any maximal random packing such as a Maximal Poisson-disk Sampling (MPS), we iteratively relocate, inject (add), or eject (remove) disks, using a set of three successively more-aggressive local operations. We may achieve a user-defined density, either more dense or more sparse, almost up to the theoretical structured limits. The tuned samples are conflict-free, retain coverage maximality, and, except in the extremes, retain the blue noise randomness properties of the input. We change the density of the packing one disk at a time, maintaining the minimum disk separation distance and the maximum domain coverage distance required of any maximal packing. These properties are local, and we can handle spatially-varying sizing functions. Using fewer points to satisfy a sizing function improves the efficiency of some applications. We apply the framework to improve the quality of meshes, removing non-obtuse angles; and to more accurately model fiber reinforced polymers for elastic and failure simulations.

  16. 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

  17. A molecular noise generator

    International Nuclear Information System (INIS)

    Lu Ting; Ferry, Michael; Hasty, Jeff; Weiss, Ron

    2008-01-01

    Recent studies have demonstrated that intracellular variations in the rate of gene expression are of fundamental importance to cellular function and development. While such 'noise' is often considered detrimental in the context of perturbing genetic systems, it can be beneficial in processes such as species diversification and facilitation of evolution. A major difficulty in exploring such effects is that the magnitude and spectral properties of the induced variations arise from some intrinsic cellular process that is difficult to manipulate. Here, we present two designs of a molecular noise generator that allow for the flexible modulation of the noise profile of a target gene. The first design uses a dual-signal mechanism that enables independent tuning of the mean and variability of an output protein. This is achieved through the combinatorial control of two signals that regulate transcription and translation separately. We then extend the design to allow for DNA copy-number regulation, which leads to a wider tuning spectrum for the output molecule. To gain a deeper understanding of the circuit's functionality in a realistic environment, we introduce variability in the input signals in order to ascertain the degree of noise induced by the control process itself. We conclude by illustrating potential applications of the noise generator, demonstrating how it could be used to ascertain the robust or fragile properties of a genetic circuit

  18. Power reactor noise

    International Nuclear Information System (INIS)

    Thie, J.A.

    1981-01-01

    Noise analysis is a growing field that offers advantages such as simplicity, low cost, and natural multivariable interactions. A major advantage, continuous and undisturbed monitoring, supplies a means of obtaining early warnings of possible reactor malfunctions, thus preventing further complications by alerting opeators to a problem - and aiding in the diagnosis of that problem - before it demands major repairs. Dr. Thie hopes to further, through detailed explanations and over 70 illustrations, the acceptance of the use of noise analysis by the nuclear utility industry. Following an introductory chapter, the theoretical basis for the various methods of noise analysis is explained, and full chapters are devoted to the fundamentals of statistics for time-domain analysis and Fourier series and related topics for frequency-domain analysis. General experimental techniques and associated theoretical considerations are reviewed, leading to discussions of practical applications in the latter half of the book. Besides chapters giving examples of neutron noise and acoustical noise, chapters are also devoted to extensive examples from pressurized water reactor and boiling water reactor power plants

  19. Retrospective Correction of Physiological Noise: Impact on Sensitivity, Specificity, and Reproducibility of Resting-State Functional Connectivity in a Reading Network Model.

    Science.gov (United States)

    Krishnamurthy, Venkatagiri; Krishnamurthy, Lisa C; Schwam, Dina M; Ealey, Ashley; Shin, Jaemin; Greenberg, Daphne; Morris, Robin D

    2018-03-01

    It is well accepted that physiological noise (PN) obscures the detection of neural fluctuations in resting-state functional connectivity (rsFC) magnetic resonance imaging. However, a clear consensus for an optimal PN correction (PNC) methodology and how it can impact the rsFC signal characteristics is still lacking. In this study, we probe the impact of three PNC methods: RETROICOR: (Glover et al., 2000 ), ANATICOR: (Jo et al., 2010 ), and RVTMBPM: (Bianciardi et al., 2009 ). Using a reading network model, we systematically explore the effects of PNC optimization on sensitivity, specificity, and reproducibility of rsFC signals. In terms of specificity, ANATICOR was found to be effective in removing local white matter (WM) fluctuations and also resulted in aggressive removal of expected cortical-to-subcortical functional connections. The ability of RETROICOR to remove PN was equivalent to removal of simulated random PN such that it artificially inflated the connection strength, thereby decreasing sensitivity. RVTMBPM maintained specificity and sensitivity by balanced removal of vasodilatory PN and local WM nuisance edges. Another aspect of this work was exploring the effects of PNC on identifying reading group differences. Most PNC methods accounted for between-subject PN variability resulting in reduced intersession reproducibility. This effect facilitated the detection of the most consistent group differences. RVTMBPM was most effective in detecting significant group differences due to its inherent sensitivity to removing spatially structured and temporally repeating PN arising from dense vasculature. Finally, results suggest that combining all three PNC resulted in "overcorrection" by removing signal along with noise.

  20. Removing Hair Safely

    Science.gov (United States)

    ... For Consumers Home For Consumers Consumer Updates Removing Hair Safely Share Tweet Linkedin Pin it More sharing ... related to common methods of hair removal. Laser Hair Removal In this method, a laser destroys hair ...

  1. The generation of 68 Gbps quantum random number by measuring laser phase fluctuations

    International Nuclear Information System (INIS)

    Nie, You-Qi; Liu, Yang; Zhang, Jun; Pan, Jian-Wei; Huang, Leilei; Payne, Frank

    2015-01-01

    The speed of a quantum random number generator is essential for practical applications, such as high-speed quantum key distribution systems. Here, we push the speed of a quantum random number generator to 68 Gbps by operating a laser around its threshold level. To achieve the rate, not only high-speed photodetector and high sampling rate are needed but also a very stable interferometer is required. A practical interferometer with active feedback instead of common temperature control is developed to meet the requirement of stability. Phase fluctuations of the laser are measured by the interferometer with a photodetector and then digitalized to raw random numbers with a rate of 80 Gbps. The min-entropy of the raw data is evaluated by modeling the system and is used to quantify the quantum randomness of the raw data. The bias of the raw data caused by other signals, such as classical and detection noises, can be removed by Toeplitz-matrix hashing randomness extraction. The final random numbers can pass through the standard randomness tests. Our demonstration shows that high-speed quantum random number generators are ready for practical usage

  2. ECG De-noising

    DEFF Research Database (Denmark)

    Kærgaard, Kevin; Jensen, Søren Hjøllund; Puthusserypady, Sadasivan

    2015-01-01

    Electrocardiogram (ECG) is a widely used noninvasive method to study the rhythmic activity of the heart and thereby to detect the abnormalities. However, these signals are often obscured by artifacts from various sources and minimization of these artifacts are of paramount important. This paper...... proposes two adaptive techniques, namely the EEMD-BLMS (Ensemble Empirical Mode Decomposition in conjunction with the Block Least Mean Square algorithm) and DWT-NN (Discrete Wavelet Transform followed by Neural Network) methods in minimizing the artifacts from recorded ECG signals, and compares...... their performance. These methods were first compared on two types of simulated noise corrupted ECG signals: Type-I (desired ECG+noise frequencies outside the ECG frequency band) and Type-II (ECG+noise frequencies both inside and outside the ECG frequency band). Subsequently, they were tested on real ECG recordings...

  3. Joyce’s Noises

    Directory of Open Access Journals (Sweden)

    Derek Attridge

    2009-10-01

    Full Text Available James Joyce uses both lexical and nonlexical onomatopoeia extensively in _Ulysses_; this essay examines some of the ways in which he employs the latter in order to convey noises of many kinds. Nonlexical onomatopoeia is particularly suited to the evocation of noise, though it can only do so in conjunction with shared literary and linguistic conventions. Several of the characters in _Ulysses_ show an interest in the representation of noise in language, but there are many more examples where there is no evidence of mental processes at work. The reader’s pleasure in Joyce’s nonlexical onomatopoeia is very seldom the result of vivid imitation; it is, as these examples testify, Joyce’s play with the workings of the device (and frequently its failure to imitate the nonlinguistic world that provides enjoyment and some insight into the relation between language and sound.

  4. 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.

  5. Random networks of Boolean cellular automata

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, Enrique [Comision Nacional de Energia Atomica, San Carlos de Bariloche (Argentina). Centro Atomico Bariloche

    1990-01-01

    Some recent results about random networks of Boolean automata -the Kauffman model- are reviewed. The structure of configuration space is explored. Ultrametricity between cycles is analyzed and the effects of noise in the dynamics are studied. (Author).

  6. Random networks of Boolean cellular automata

    International Nuclear Information System (INIS)

    Miranda, Enrique

    1990-01-01

    Some recent results about random networks of Boolean automata -the Kauffman model- are reviewed. The structure of configuration space is explored. Ultrametricity between cycles is analyzed and the effects of noise in the dynamics are studied. (Author)

  7. 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

  8. Noise-sustained fluctuations in stochastic dynamics with a delay.

    Science.gov (United States)

    D'Odorico, Paolo; Laio, Francesco; Ridolfi, Luca

    2012-04-01

    Delayed responses to external drivers are ubiquitous in environmental, social, and biological processes. Delays may induce oscillations, Hopf bifurcations, and instabilities in deterministic systems even in the absence of nonlinearities. Despite recent advances in the study of delayed stochastic differential equations, the interaction of random drivers with delays remains poorly understood. In particular, it is unclear whether noise-induced behaviors may emerge from these interactions. Here we show that noise may enhance and sustain transient periodic oscillations inherent to deterministic delayed systems. We investigate the conditions conducive to the emergence and disappearance of these dynamics in a linear system in the presence of both additive and multiplicative noise.

  9. Effect of multiplicative noise on stationary stochastic process

    Science.gov (United States)

    Kargovsky, A. V.; Chikishev, A. Yu.; Chichigina, O. A.

    2018-03-01

    An open system that can be analyzed using the Langevin equation with multiplicative noise is considered. The stationary state of the system results from a balance of deterministic damping and random pumping simulated as noise with controlled periodicity. The dependence of statistical moments of the variable that characterizes the system on parameters of the problem is studied. A nontrivial decrease in the mean value of the main variable with an increase in noise stochasticity is revealed. Applications of the results in several physical, chemical, biological, and technical problems of natural and humanitarian sciences are discussed.

  10. Risk factor noise - otological aspects

    Energy Technology Data Exchange (ETDEWEB)

    Haas, E

    1984-06-11

    After a short review of the anatomy and physiology of the inner ear the pathogenesis of chronic noise-induced hearing loss is discussed. The exposure to noise results first in a temporary but reversible threshold shift. But if the exposure to noise was exceedingly high or if the rest period would have required further noise reduction, a state of so-called auditory fatigue develops, finally leading to noise-induced hearing loss, a state which is considered irreversible. The noise-perception varies greatly among individuals and thus it is impossible to determine a certain noise intensity above which noise leasions will to be expected. It is generally accepted, that longterm exposure to noise above 85 dB (A) may lead to hearing loss in a portion of the exposed persons.

  11. Diode laser pumped solid state laser. Part IV. ; Noise analysis. Handotai laser reiki kotai laser. 4. ; Noise kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Sakurai, H.; Seno, T.; Tanabe, Y. (Asahi Glass Co. Ltd., Tokyo (Japan))

    1991-06-10

    Concerning the second harmonic generation(SHG) of diode laser pumped solid state laser using a nonlinear optical material, the researches are carried out to pracitically apply to the optical pickup. Therefore, the reduction of output optical noise has become the important researching subject. The theoretical and experimental analyses of noise generating mechanism were carried out for the system in which Nd;YAG as the laser diode and KTP (KTiOPO {sub 4}) as the nonlinear optical crystal were used. The following findings for the noise generating mechanism could be obtained: The competitive interaction between the polarization modes was dominant noise mechanism in the high frequency range from 1 to 20MHz and the noise could be removed sufficiently by using the QWP(quarter wave plate). On the other hand, the noise observed in the low frequency range from 100 to 200kHz depended on the resonance length, agreed qualitatively with the theoretical analysis of the noise to the competitive longitudinal modes and agreed quantitatively with the noise generating frequency range. 10 refs., 13 figs., 1 tab.

  12. Wind turbine noise diagnostics

    International Nuclear Information System (INIS)

    Richarz, W.; Richarz, H.

    2009-01-01

    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.

  13. Exploring Noise: Sound Pollution.

    Science.gov (United States)

    Rillo, Thomas J.

    1979-01-01

    Part one of a three-part series about noise pollution and its effects on humans. This section presents the background information for teachers who are preparing a unit on sound. The next issues will offer learning activities for measuring the effects of sound and some references. (SA)

  14. Nodule detection in digital chest radiography: Effect of anatomical noise

    International Nuclear Information System (INIS)

    Baath, M.; Haakansson, M.; Boerjesson, S.; Hoeschen, C.; Tischenko, O.; Kheddache, S.; Vikgren, J.; Maansson, L. G.

    2005-01-01

    The image background resulting from imaged anatomy can be divided into those components that are meaningful to the observers, in the sense that they are recognised as separate structures, and those that are not. These latter components (referred to as anatomical noise) can be removed using a method developed within the RADIUS group. The aim of the present study was to investigate whether the removal of the anatomical noise results in images where lung nodules with lower contrast can be detected. A receiver operating characteristic (ROC) study was therefore conducted using two types of images: clinical chest images and chest images in which the anatomical noise had been removed. Simulated designer nodules with a full-width-at-fifth-maximum of 10 mm but with varying contrast were added to the images. The contrast needed to obtain an area under the ROC curve of 0.80, C0.8, was used as a measure of detectability (a low value of C0.8 represents a high delectability). Five regions of the chest X ray were investigated and it was found that in all regions the removal of anatomical noise led to images with lower C0.8 than the original images. On average, C0.8 was 20% higher in the original images, ranging from 7% (the lateral pulmonary regions) to 41% (the upper mediastinal regions). (authors)

  15. New Hybrid Variational Recovery Model for Blurred Images with Multiplicative Noise

    DEFF Research Database (Denmark)

    Dong, Yiqiu; Zeng, Tieyong

    2013-01-01

    A new hybrid variational model for recovering blurred images in the presence of multiplicative noise is proposed. Inspired by previous work on multiplicative noise removal, an I-divergence technique is used to build a strictly convex model under a condition that ensures the uniqueness...

  16. An investigation of excess noise in transition-edge sensors on a solid silicon substrate

    International Nuclear Information System (INIS)

    Crowder, S.G.; Lindeman, M.A.; Anderson, M.B.; Bandler, S.R.; Bilgri, N.; Bruijn, M.P.; Chervenak, J.; Figueroa-Feliciano, E.; Finkbeiner, F.; Germeau, A.; Hoevers, H.F.C.; Iyomoto, N.; Kelly, R.; Kilbourne, C.A.; Lai, T.; Man, J.; McCammon, D.; Nelms, K.L.; Porter, F.S.; Rocks, L.; Saab, T.; Sadleir, J.; Vidugiris, G.

    2006-01-01

    Transition-edge sensors (TESs) exhibit two major types of excess noise above the expected and unavoidable thermodynamic fluctuation noise (TFN) to the heat sink and Johnson noise. High-resistance TESs such as those made by the Netherlands Institute for Space Research (SRON) show excess noise consistent with internal TFN (ITFN) caused by random energy transport within the TES itself while low resistance TESs show an excess voltage noise of unknown origin seemingly unrelated to temperature fluctuations. Running a high-resistance TES on a high thermal conductivity substrate should suppress ITFN and allow detection of any excess voltage noise. We tested two TESs on a solid silicon substrate fabricated by SRON of a relatively high normal state resistance of ∼200 mΩ. After determining a linear model of the TES response to noise for the devices, we found little excess TFN and little excess voltage noise for bias currents of up to ∼20 μA

  17. A fourth order PDE based fuzzy c- means approach for segmentation of microscopic biopsy images in presence of Poisson noise for cancer detection.

    Science.gov (United States)

    Kumar, Rajesh; Srivastava, Subodh; Srivastava, Rajeev

    2017-07-01

    For cancer detection from microscopic biopsy images, image segmentation step used for segmentation of cells and nuclei play an important role. Accuracy of segmentation approach dominate the final results. Also the microscopic biopsy images have intrinsic Poisson noise and if it is present in the image the segmentation results may not be accurate. The objective is to propose an efficient fuzzy c-means based segmentation approach which can also handle the noise present in the image during the segmentation process itself i.e. noise removal and segmentation is combined in one step. To address the above issues, in this paper a fourth order partial differential equation (FPDE) based nonlinear filter adapted to Poisson noise with fuzzy c-means segmentation method is proposed. This approach is capable of effectively handling the segmentation problem of blocky artifacts while achieving good tradeoff between Poisson noise removals and edge preservation of the microscopic biopsy images during segmentation process for cancer detection from cells. The proposed approach is tested on breast cancer microscopic biopsy data set with region of interest (ROI) segmented ground truth images. The microscopic biopsy data set contains 31 benign and 27 malignant images of size 896 × 768. The region of interest selected ground truth of all 58 images are also available for this data set. Finally, the result obtained from proposed approach is compared with the results of popular segmentation algorithms; fuzzy c-means, color k-means, texture based segmentation, and total variation fuzzy c-means approaches. The experimental results shows that proposed approach is providing better results in terms of various performance measures such as Jaccard coefficient, dice index, Tanimoto coefficient, area under curve, accuracy, true positive rate, true negative rate, false positive rate, false negative rate, random index, global consistency error, and variance of information as compared to other

  18. Noise cancellation properties of displacement noise free interferometer

    International Nuclear Information System (INIS)

    Sato, Shuichi; Kawamura, Seiji; Nishizawa, Atsushi; Chen Yanbei

    2010-01-01

    We have demonstrated the practical feasibility of a displacement- and frequency-noise-free laser interferometer (DFI) by partially implementing a recently proposed optical configuration using bi-directional Mach-Zehnder interferometers (MZIs). The noise cancellation efficiency was evaluated by comparing the displacement noise spectrum of the MZIs and the DFI, demonstrating up to 50 dB of noise cancellation. In addition, the possible extension of DFI as QND device is explored.

  19. Entanglement probabilities of polymers: a white noise functional approach

    International Nuclear Information System (INIS)

    Bernido, Christopher C; Carpio-Bernido, M Victoria

    2003-01-01

    The entanglement probabilities for a highly flexible polymer to wind n times around a straight polymer are evaluated using white noise analysis. To introduce the white noise functional approach, the one-dimensional random walk problem is taken as an example. The polymer entanglement scenario, viewed as a random walk on a plane, is then treated and the entanglement probabilities are obtained for a magnetic flux confined along the straight polymer, and a case where an entangled polymer is subjected to the potential V = f-dot(s)θ. In the absence of the magnetic flux and the potential V, the entanglement probabilities reduce to a result obtained by Wiegel

  20. The Traffic Noise Index: A Method of Controlling Noise Nuisance.

    Science.gov (United States)

    Langdon, F. J.; Scholes, W. E.

    This building research survey is an analysis of the social nuisance caused by urban motor ways and their noise. The Traffic Noise Index is used to indicate traffic noises and their effects on architectural designs and planning, while suggesting the need for more and better window insulation and acoustical barriers. Overall concern is for--(1)…

  1. Noise sensitivity and reactions to noise and other environmental conditions

    NARCIS (Netherlands)

    Miedema, H.M.E.; Vos, H.

    2003-01-01

    This article integrates findings from the literature and new results regarding noise sensitivity. The new results are based on analyses of 28 combined datasets (N=23 038), and separate analyses of a large aircraft noise study (N=10939). Three topics regarding noise sensitivity are discussed, namely,

  2. Evaluating noise abatement measures using strategic noise maps

    NARCIS (Netherlands)

    Borst, H.C.; Miedema, H.M.E.; Laan, W.P.N. van der; Lohman, W.J.A.

    2006-01-01

    Noise annoyance due to transportation is widespread in industrialized countries and in urban areas in the developing countries. The European Noise Directive (END) requires an assessment of the noise situation as well as the formulation of action plans for the reduction of the number of people

  3. 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...

  4. Rating environmental noise on the basis of noise maps

    NARCIS (Netherlands)

    Miedema, H.M.E.; Borst, H.C.

    2006-01-01

    A system that rates noise on the basis of noise maps has been developed which is based on empirical exposure-response relationships, so that effects in the community will be lower if the system gives a better rating. It is consistent with noise metrics and effect endpoint chosen in the EU, i.e., it

  5. Study on phase noise induced by 1/f noise of the modulator drive circuit in high-sensitivity fiber optic gyroscope

    Science.gov (United States)

    Teng, Fei; Jin, Jing; Li, Yong; Zhang, Chunxi

    2018-05-01

    The contribution of modulator drive circuit noise as a 1/f noise source to the output noise of the high-sensitivity interferometric fiber optic gyroscope (IFOG) was studied here. A noise model of closed-loop IFOG was built. By applying the simulated 1/f noise sequence into the model, a gyroscope output data series was acquired, and the corresponding power spectrum density (PSD) and the Allan variance curve were calculated to analyze the noise characteristic. The PSD curve was in the spectral shape of 1/f, which verifies that the modulator drive circuit induced a low frequency 1/f phase noise into the gyroscope. The random walk coefficient (RWC), a standard metric to characterize the noise performance of the IFOG, was calculated according to the Allan variance curve. Using an operational amplifier with an input 1/f noise of 520 nV/√Hz at 1 Hz, the RWC induced by this 1/f noise was 2 × 10-4°/√h, which accounts for 63% of the total RWC. To verify the correctness of the noise model we proposed, a high-sensitivity gyroscope prototype was built and tested. The simulated Allan variance curve gave a good rendition of the prototype actual measured curve. The error percentage between the simulated RWC and the measured value was less than 13%. According to the model, a noise reduction method is proposed and the effectiveness is verified by the experiment.

  6. Framing sound: Using expectations to reduce environmental noise annoyance.

    Science.gov (United States)

    Crichton, Fiona; Dodd, George; Schmid, Gian; Petrie, Keith J

    2015-10-01

    Annoyance reactions to environmental noise, such as wind turbine sound, have public health implications given associations between annoyance and symptoms related to psychological distress. In the case of wind farms, factors contributing to noise annoyance have been theorised to include wind turbine sound characteristics, the noise sensitivity of residents, and contextual aspects, such as receiving information creating negative expectations about sound exposure. The experimental aim was to assess whether receiving positive or negative expectations about wind farm sound would differentially influence annoyance reactions during exposure to wind farm sound, and also influence associations between perceived noise sensitivity and noise annoyance. Sixty volunteers were randomly assigned to receive either negative or positive expectations about wind farm sound. Participants in the negative expectation group viewed a presentation which incorporated internet material indicating that exposure to wind turbine sound, particularly infrasound, might present a health risk. Positive expectation participants viewed a DVD which framed wind farm sound positively and included internet information about the health benefits of infrasound exposure. Participants were then simultaneously exposed to sub-audible infrasound and audible wind farm sound during two 7 min exposure sessions, during which they assessed their experience of annoyance. Positive expectation participants were significantly less annoyed than negative expectation participants, while noise sensitivity only predicted annoyance in the negative group. Findings suggest accessing negative information about sound is likely to trigger annoyance, particularly in noise sensitive people and, importantly, portraying sound positively may reduce annoyance reactions, even in noise sensitive individuals. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Noise-Induced Hearing Loss

    Science.gov (United States)

    ... Home » Health Info » Hearing, Ear Infections, and Deafness Noise-Induced Hearing Loss On this page: What is ... I find additional information about NIHL? What is noise-induced hearing loss? Every day, we experience sound ...

  8. 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 words......, we put a new tool in the box that computes fast high-quality noise. In addition to being free of artifacts, the noise we present does not rely on tabulated data (everything is computed on the fly) and it is easy to adjust quality vs. quantity for the noise. The noise is based on point rendering (like...... spot noise), but it extends to more than two dimensions. The fact that it is based on point rendering makes art direction of the noise much easier....

  9. Spectral Characteristics of Pitot Noise

    Science.gov (United States)

    Hornung, H. G.; Parziale, N. J.

    For experimental studies of transition from laminar to turbulent boundary layer flow it is important to know the ambient noise spectrum in the facility. In supersonic wind tunnels this is often assessed by measuring pitot pressure noise.

  10. Vocal Noise Cancellation From Respiratory Sounds

    National Research Council Canada - National Science Library

    Moussavi, Zahra

    2001-01-01

    Although background noise cancellation for speech or electrocardiographic recording is well established, however when the background noise contains vocal noises and the main signal is a breath sound...

  11. Randomization tests

    CERN Document Server

    Edgington, Eugene

    2007-01-01

    Statistical Tests That Do Not Require Random Sampling Randomization Tests Numerical Examples Randomization Tests and Nonrandom Samples The Prevalence of Nonrandom Samples in Experiments The Irrelevance of Random Samples for the Typical Experiment Generalizing from Nonrandom Samples Intelligibility Respect for the Validity of Randomization Tests Versatility Practicality Precursors of Randomization Tests Other Applications of Permutation Tests Questions and Exercises Notes References Randomized Experiments Unique Benefits of Experiments Experimentation without Mani

  12. Measurement of Noise in Supercapacitors

    OpenAIRE

    Szewczyk Arkadiusz

    2017-01-01

    A developed method and measurement setup for measurement of noise generated in a supercapacitor is presented. The requirements for noise data recording are considered and correlated with working modes of supercapacitors. An example of results of low-frequency noise measurements in commercially available supercapacitors are presented. The ability of flicker noise measurements suggests that they can be used to assess quality of tested supercapacitors.

  13. Measurement of Noise in Supercapacitors

    Directory of Open Access Journals (Sweden)

    Szewczyk Arkadiusz

    2017-12-01

    Full Text Available A developed method and measurement setup for measurement of noise generated in a supercapacitor is presented. The requirements for noise data recording are considered and correlated with working modes of supercapacitors. An example of results of low-frequency noise measurements in commercially available supercapacitors are presented. The ability of flicker noise measurements suggests that they can be used to assess quality of tested supercapacitors.

  14. ''1/f noise'' in music: Music from 1/f noise

    Energy Technology Data Exchange (ETDEWEB)

    Voss, R.F.; Clarke, J.

    1978-01-01

    The spectral density of fluctuations in the audio power of many musical selections and of English speech varies approximately as 1/f (f is the frequency) down to a frequency of 5 x 10/sup -4/ Hz. This result implies that the audio-power fluctuations are correlated over all times in the same manner as ''1/f noise'' in electronic components. The frequency fluctuations of music also have a 1/f spectral density at frequencies down to the inverse of the length of the piece of music. The frequency fluctuations of English speech have a quite different behavior, with a single characteristic time of about 0.1 s, the average length of a syllable. The observations on music suggest that 1/f noise is a good choice for stochastic composition. Compositions in which the frequency and duration of each note were determined by 1/f noise sources sounded pleasing. Those generated by white-noise sources sounded too random, while those generated by 1/f/sup 2/ noise sounded too correlated.

  15. ARSENIC REMOVAL BY IRON REMOVAL PROCESSES

    Science.gov (United States)

    Presentation will discuss the removal of arsenic from drinking water using iron removal processes that include oxidation/filtration and the manganese greensand processes. Presentation includes results of U.S. EPA field studies conducted in Michigan and Ohio on existing iron remo...

  16. Noise simulation in cone beam CT imaging with parallel computing

    International Nuclear Information System (INIS)

    Tu, S.-J.; Shaw, Chris C; Chen, Lingyun

    2006-01-01

    We developed a computer noise simulation model for cone beam computed tomography imaging using a general purpose PC cluster. This model uses a mono-energetic x-ray approximation and allows us to investigate three primary performance components, specifically quantum noise, detector blurring and additive system noise. A parallel random number generator based on the Weyl sequence was implemented in the noise simulation and a visualization technique was accordingly developed to validate the quality of the parallel random number generator. In our computer simulation model, three-dimensional (3D) phantoms were mathematically modelled and used to create 450 analytical projections, which were then sampled into digital image data. Quantum noise was simulated and added to the analytical projection image data, which were then filtered to incorporate flat panel detector blurring. Additive system noise was generated and added to form the final projection images. The Feldkamp algorithm was implemented and used to reconstruct the 3D images of the phantoms. A 24 dual-Xeon PC cluster was used to compute the projections and reconstructed images in parallel with each CPU processing 10 projection views for a total of 450 views. Based on this computer simulation system, simulated cone beam CT images were generated for various phantoms and technique settings. Noise power spectra for the flat panel x-ray detector and reconstructed images were then computed to characterize the noise properties. As an example among the potential applications of our noise simulation model, we showed that images of low contrast objects can be produced and used for image quality evaluation

  17. Aircraft Noise Reduction Subproject Overview

    Science.gov (United States)

    Fernandez, Hamilton; Nark, Douglas M.; Van Zante, Dale E.

    2016-01-01

    The material presents highlights of propulsion and airframe noise research being completed for the Advanced Air Transport Technology Project. The basis of noise reduction plans along with representative work for the airframe, propulsion, and propulsion-airframe integration is discussed for the Aircraft Noise reduction Subproject.

  18. Background noise levels in Europe

    OpenAIRE

    Gjestland, Truls

    2008-01-01

    - This report gives a brief overview of typical background noise levels in Europe, and suggests a procedure for the prediction of background noise levels based on population density. A proposal for the production of background noise maps for Europe is included.

  19. Practical Ranges of Loudness Levels of Various Types of Environmental Noise, Including Traffic Noise, Aircraft Noise, and Industrial Noise

    Directory of Open Access Journals (Sweden)

    Sabine A. Janssen

    2011-05-01

    Full Text Available In environmental noise control one commonly employs the A-weighted sound level as an approximate measure of the effect of noise on people. A measure that is more closely related to direct human perception of noise is the loudness level. At constant A-weighted sound level, the loudness level of a noise signal varies considerably with the shape of the frequency spectrum of the noise signal. In particular the bandwidth of the spectrum has a large effect on the loudness level, due to the effect of critical bands in the human hearing system. The low-frequency content of the spectrum also has an effect on the loudness level. In this note the relation between loudness level and A-weighted sound level is analyzed for various environmental noise spectra, including spectra of traffic noise, aircraft noise, and industrial noise. From loudness levels calculated for these environmental noise spectra, diagrams are constructed that show the relation between loudness level, A‑weighted sound level, and shape of the spectrum. The diagrams show that the upper limits of the loudness level for broadband environmental noise spectra are about 20 to 40 phon higher than the lower limits for narrowband spectra, which correspond to the loudness levels of pure tones. The diagrams are useful for assessing limitations and potential improvements of environmental noise control methods and policy based on A-weighted sound levels.

  20. Practical ranges of loudness levels of various types of environmental noise, including traffic noise, aircraft noise, and industrial noise

    NARCIS (Netherlands)

    Salomons, E.M.; Janssen, S.A.

    2011-01-01

    In environmental noise control one commonly employs the A-weighted sound level as an approximate measure of the effect of noise on people. A measure that is more closely related to direct human perception of noise is the loudness level. At constant A-weighted sound level, the loudness level of a

  1. Chaos and noise.

    Science.gov (United States)

    He, Temple; Habib, Salman

    2013-09-01

    Simple dynamical systems--with a small number of degrees of freedom--can behave in a complex manner due to the presence of chaos. Such systems are most often (idealized) limiting cases of more realistic situations. Isolating a small number of dynamical degrees of freedom in a realistically coupled system generically yields reduced equations with terms that can have a stochastic interpretation. In situations where both noise and chaos can potentially exist, it is not immediately obvious how Lyapunov exponents, key to characterizing chaos, should be properly defined. In this paper, we show how to do this in a class of well-defined noise-driven dynamical systems, derived from an underlying Hamiltonian model.

  2. White noise on bialgebras

    CERN Document Server

    Schürmann, Michael

    1993-01-01

    Stochastic processes with independent increments on a group are generalized to the concept of "white noise" on a Hopf algebra or bialgebra. The main purpose of the book is the characterization of these processes as solutions of quantum stochastic differential equations in the sense of R.L. Hudsonand K.R. Parthasarathy. The notes are a contribution to quantum probability but they are also related to classical probability, quantum groups, and operator algebras. The Az ma martingales appear as examples of white noise on a Hopf algebra which is a deformation of the Heisenberg group. The book will be of interest to probabilists and quantum probabilists. Specialists in algebraic structures who are curious about the role of their concepts in probablility theory as well as quantum theory may find the book interesting. The reader should havesome knowledge of functional analysis, operator algebras, and probability theory.

  3. Noise Phobia in Dog

    Directory of Open Access Journals (Sweden)

    Mangle

    Full Text Available Fear of thunderstorms and other forms of noise phobia are common problems in dogs. Administering medications along with changing the pet’s environment, and using behavior modification techniques can help ease the fear. Above all, do not give your pet any attention or reward when he is showing signs of fear; this will only reinforce the fearful behavior. [Veterinary World 2008; 1(11.000: 351-352

  4. Thermal noise engines

    OpenAIRE

    Kish, Laszlo B.

    2010-01-01

    Electrical heat engines driven by the Johnson-Nyquist noise of resistors are introduced. They utilize Coulomb's law and the fluctuation-dissipation theorem of statistical physics that is the reverse phenomenon of heat dissipation in a resistor. No steams, gases, liquids, photons, combustion, phase transition, or exhaust/pollution are present here. In these engines, instead of heat reservoirs, cylinders, pistons and valves, resistors, capacitors and switches are the building elements. For the ...

  5. [The century of noise].

    Science.gov (United States)

    Pivato, Stefano

    2011-01-01

    When did, actually, "noise pollution" begin to coexist along with our daily life and activities and change our environmental natural sounds, which hadn't changed for centuries? Industrial revolution, first, and the introduction of new technologies later, introduced "noise" as one of the most relevant features that marked the development of progress. Later on, it became the distinctive characteristic of the XX century. The incessant rumble of industrial machinery, of weapons and cannons from the wars, the roar of cars in the streets and aeroplanes from the sky, the deafening sound of XX century music, as well as the shouting out of new political ideas suddenly invaded the new century. They became part of our daily life so much as almost to become a new lay religion of modernity. As the century proceeded towards economic boom, a "new noisy Man" complied with this change, becoming the anthropologic prototype who was able to adapt to the new style of life and even contribute to its expansion. All this finally allows, to day, a definition of the XX century as the "century of noise".

  6. Universal Majorana thermoelectric noise

    Science.gov (United States)

    Smirnov, Sergey

    2018-04-01

    Thermoelectric phenomena resulting from an interplay between particle flows induced by electric fields and temperature inhomogeneities are extremely insightful as a tool providing substantial knowledge about the microscopic structure of a given system. By tuning, e.g., parameters of a nanoscopic system coupled via tunneling mechanisms to two contacts, one may achieve various situations where the electric current induced by an external bias voltage competes with the electric current excited by the temperature difference of the two contacts. Even more exciting physics emerges when the system's electronic degrees freedom split to form Majorana fermions which make the thermoelectric dynamics universal. Here, we propose revealing these unique universal signatures of Majorana fermions in strongly nonequilibrium quantum dots via noise of the thermoelectric transport beyond linear response. It is demonstrated that whereas mean thermoelectric quantities are only universal at large-bias voltages, the noise of the electric current excited by an external bias voltage and the temperature difference of the contacts is universal at any bias voltage. We provide truly universal, i.e., independent of the system's parameters, thermoelectric ratios between nonlinear response coefficients of the noise and mean current at large-bias voltages where experiments may easily be performed to uniquely detect these truly universal Majorana thermoelectric signatures.

  7. Tinnitus and leisure noise.

    Science.gov (United States)

    Williams, Warwick; Carter, Lyndal

    2017-04-01

    To study the relationship of life-time noise exposure and experience of tinnitus. Audiometric measures included otoscopy, pure tone air- and bone-conduction hearing threshold levels (HTL) and otoacoustic emissions (OAEs). Participants completed questionnaires including demographic information, past hearing health, history of participation in loud leisure activities, and attitudes to noise. A representative sample (1435) of the young (11-35 years old) Australian population. Of the sample, 63% indicated they experienced tinnitus in some form. There was no correlation of tinnitus experience with HTL or OAE amplitudes. Although median octave band HTLs for those who experienced tinnitus "all the time" were slightly higher for those who did not, neither group exhibited HTLs outside clinically-normal values. Of those who experienced tinnitus a direct correlation was found between frequency of experience of tinnitus and increasing cumulative, life-time noise exposure. Those who experienced tinnitus were more likely to report noticing deterioration in their hearing ability over time and to report difficulty hearing in quiet and/or noisy situations. Experience of tinnitus was found throughout this young population but not associated with HTLs or variation in OAE amplitudes. Males experienced 'permanent' tinnitus at significantly greater rate than females.

  8. The diversity and unity of reactor noise theory

    International Nuclear Information System (INIS)

    Kuang, Zhifeng

    2001-01-01

    The study of reactor noise theory concerns questions about cause and effect relationships, and the utilisation of random noise in nuclear reactor systems. The diversity of reactor noise theory arises from the variety of noise sources, the various mathematical treatments applied and the various practical purposes. The neutron noise in zero-energy systems arises from the fluctuations in the number of neutrons per fission, the time between nuclear events, and the type of reactions. It can be used to evaluate system parameters. The mathematical treatment is based on the master equation of stochastic branching processes. The noise in power reactor systems is given rise by random processes of technological origin such as vibration of mechanical parts, boiling of the coolant, fluctuations of temperature and pressure. It can be used to monitor the reactor behaviour with the possibility of detecting malfunctions at an early stage. The mathematical treatment is based on the Langevin equation. The unity of reactor noise theory arises from the fact that the useful information from noise is embedded in the second moments of random variables, which lends the possibility of building up a unified mathematical description and analysis of the various reactor noise sources. Exploring such possibilities is the main subject among the three major topics reported in this thesis. The first subject is within the zero power noise in steady media, and we reported on the extension of the existing theory to more general cases. In Paper I, by use of the master equation approach, we have derived the most general Feynman- and Rossi-alpha formulae so far by taking the full joint statistics of the prompt and all the six groups of delayed neutron precursors, and a multiple emission source into account. The involved problems are solved with a combination of effective analytical techniques and symbolic algebra codes. Paper II gives a numerical evaluation of these formulae. An assessment of the

  9. SU-C-207B-02: Maximal Noise Reduction Filter with Anatomical Structures Preservation

    Energy Technology Data Exchange (ETDEWEB)

    Maitree, R; Guzman, G; Chundury, A; Roach, M; Yang, D [Washington University School of Medicine, St Louis, MO (United States)

    2016-06-15

    Purpose: All medical images contain noise, which can result in an undesirable appearance and can reduce the visibility of anatomical details. There are varieties of techniques utilized to reduce noise such as increasing the image acquisition time and using post-processing noise reduction algorithms. However, these techniques are increasing the imaging time and cost or reducing tissue contrast and effective spatial resolution which are useful diagnosis information. The three main focuses in this study are: 1) to develop a novel approach that can adaptively and maximally reduce noise while preserving valuable details of anatomical structures, 2) to evaluate the effectiveness of available noise reduction algorithms in comparison to the proposed algorithm, and 3) to demonstrate that the proposed noise reduction approach can be used clinically. Methods: To achieve a maximal noise reduction without destroying the anatomical details, the proposed approach automatically estimated the local image noise strength levels and detected the anatomical structures, i.e. tissue boundaries. Such information was used to adaptively adjust strength of the noise reduction filter. The proposed algorithm was tested on 34 repeating swine head datasets and 54 patients MRI and CT images. The performance was quantitatively evaluated by image quality metrics and manually validated for clinical usages by two radiation oncologists and one radiologist. Results: Qualitative measurements on repeated swine head images demonstrated that the proposed algorithm efficiently removed noise while preserving the structures and tissues boundaries. In comparisons, the proposed algorithm obtained competitive noise reduction performance and outperformed other filters in preserving anatomical structures. Assessments from the manual validation indicate that the proposed noise reduction algorithm is quite adequate for some clinical usages. Conclusion: According to both clinical evaluation (human expert ranking) and

  10. SU-C-207B-02: Maximal Noise Reduction Filter with Anatomical Structures Preservation

    International Nuclear Information System (INIS)

    Maitree, R; Guzman, G; Chundury, A; Roach, M; Yang, D

    2016-01-01

    Purpose: All medical images contain noise, which can result in an undesirable appearance and can reduce the visibility of anatomical details. There are varieties of techniques utilized to reduce noise such as increasing the image acquisition time and using post-processing noise reduction algorithms. However, these techniques are increasing the imaging time and cost or reducing tissue contrast and effective spatial resolution which are useful diagnosis information. The three main focuses in this study are: 1) to develop a novel approach that can adaptively and maximally reduce noise while preserving valuable details of anatomical structures, 2) to evaluate the effectiveness of available noise reduction algorithms in comparison to the proposed algorithm, and 3) to demonstrate that the proposed noise reduction approach can be used clinically. Methods: To achieve a maximal noise reduction without destroying the anatomical details, the proposed approach automatically estimated the local image noise strength levels and detected the anatomical structures, i.e. tissue boundaries. Such information was used to adaptively adjust strength of the noise reduction filter. The proposed algorithm was tested on 34 repeating swine head datasets and 54 patients MRI and CT images. The performance was quantitatively evaluated by image quality metrics and manually validated for clinical usages by two radiation oncologists and one radiologist. Results: Qualitative measurements on repeated swine head images demonstrated that the proposed algorithm efficiently removed noise while preserving the structures and tissues boundaries. In comparisons, the proposed algorithm obtained competitive noise reduction performance and outperformed other filters in preserving anatomical structures. Assessments from the manual validation indicate that the proposed noise reduction algorithm is quite adequate for some clinical usages. Conclusion: According to both clinical evaluation (human expert ranking) and

  11. Handbook for industrial noise control

    Science.gov (United States)

    The basic principles of sound, measuring techniques, and instrumentation associated with general purpose noise control are discussed. Means for identifying and characterizing a noise problem so that subsequent work may provide the most efficient and cost effective solution are outlined. A methodology for choosing appropriate noise control materials and the proper implementation of control procedures is detailed. The most significant NASA sponsored contributions to the state of the art development of optimum noise control technologies are described including cases in which aeroacoustics and related research have shed some light on ways of reducing noise generation at its source.

  12. Active control of the noise

    International Nuclear Information System (INIS)

    Rodriguez V, Luis Alfonso; Lopez Q, Jose German

    2001-01-01

    The problems of acoustic noise are more and more preponderant in the measure in that the amount of equipment and industrial machinery is increased such as fans, transformers, compressors etc. the use of devices passive mechanics for the reduction of the noise is effective and very appreciated because its effects embrace a wide range of acoustic frequency. However, to low frequencies, such devices become too big and expensive besides that present a tendency to do not effective. The control of active noise, CAN, using the electronic generation anti-noise, constitutes an interesting solution to the problem because their operation principle allows achieving an appreciable reduction of the noise by means of the use of compact devices. The traditional techniques for the control of acoustic noise like barriers and silenced to attenuate it, are classified as passive and their works has been accepted as norm as for the treatment of problems of noise it refers. Such techniques are considered in general very effective in the attenuation of noise of wide band. However, for low frequency, the required passive structures are too big and expensive; also, their effectiveness diminishes flagrantly, that which makes them impractical in many applications. The active suppression is profiled like a practical alternative for the reduction of acoustic noise. The idea in the active treatment of the noise it contemplates the use of a device electro-acoustic, like a speaker for example that it cancels to the noise by the generation of sounds of Same width and of contrary phase (anti-noise). The cancellation phenomenon is carried out when the ant-noise combines acoustically with the noise, what is in the cancellation of both sounds. The effectiveness of the cancellation of the primary source of noise depends on the precision with which the width and the phase of the generated ant-noise are controlled. The active control of noise, ANC (activates noise control), it is being investigated for

  13. Measurements techniques for transportation noise

    International Nuclear Information System (INIS)

    Brambilla, G.

    2001-01-01

    The noise from transport systems (roads, railways and aircraft) are increasing more and more both in space and in time and, therefore, they are still the major factor responsible for environmental noise pollution. The population exposed to transport noise is also increasing, and the corresponding health effects on people (i.e. annoyance and sleep disturbance) become more severe. Due to this current situation international and national legislation has been issued and implemented to reduce the harmful effects of such noise. This paper describes the techniques prescribed by recent Italian legislation to measure road, railway and aircraft noise. (author)

  14. Noise tolerant spatiotemporal chaos computing.

    Science.gov (United States)

    Kia, Behnam; Kia, Sarvenaz; Lindner, John F; Sinha, Sudeshna; Ditto, William L

    2014-12-01

    We introduce and design a noise tolerant chaos computing system based on a coupled map lattice (CML) and the noise reduction capabilities inherent in coupled dynamical systems. The resulting spatiotemporal chaos computing system is more robust to noise than a single map chaos computing system. In this CML based approach to computing, under the coupled dynamics, the local noise from different nodes of the lattice diffuses across the lattice, and it attenuates each other's effects, resulting in a system with less noise content and a more robust chaos computing architecture.

  15. Genetic noise control via protein oligomerization

    Directory of Open Access Journals (Sweden)

    Almaas Eivind

    2008-11-01

    Full Text Available Abstract Background 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 dynamic role of protein-protein interactions. Results 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 binding-unbinding kinetics among proteins, 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 random switching rate. Hence, the dimer promotes the robust function of bistable switches by preventing the uninduced (induced state from randomly being induced (uninduced. Conclusion 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 regulatory circuits

  16. Impact of environmental noise on growth and neuropsychological development of newborn rats.

    Science.gov (United States)

    Zheng, Yanyan; Meng, Meng; Zhao, Congmin; Liao, Wei; Zhang, Yuping; Wang, Liyan; Wen, Enyi

    2014-05-01

    We aimed to investigate the effects of environmental noise exposure on the growth and neuropsychological development in neonatal rats. Twenty-four postnatal 7-day-old Sprague-Dawley rats were randomly assigned into control, high-noise and reduced noise groups. The rats in the high-noise group were exposed to 90 dB white noise, and those in the control group were grown under standard condition, while those in the reduced noise group were exposed to standard condition with sound-absorbing cotton. Ten, 15, and 20 days post noise exposure, both the body weight and length of the rats in high-noise group were lower than those in the control and reduced noise groups, respectively. The secretion of growth hormone was significantly decreased in the rats exposed to high noise environment, compared to those exposed to standard condition and reduced noise. More interestingly, the swimming distance was apparently increased and the swimming speed was significantly decreased in high-noise group compared with those in control and reduced noise groups. Importantly, the mRNA and protein levels of SYP in the rats hippocampus were significantly decreased in high-noise group compare with those in control and reduced noise groups. Similarly, the positive expression of SYP in the CA1 region of hippocampus was also significantly decreased in the high noise group rats. In conclusion, our results demonstrated that high noise exposure could decrease the production of growth hormone and SYP in neonatal rats, which may retard the growth of weight and length and the capability of learning and memory. Copyright © 2014 Wiley Periodicals, Inc.

  17. Hybrid colored noise process with space-dependent switching rates

    Science.gov (United States)

    Bressloff, Paul C.; Lawley, Sean D.

    2017-07-01

    A fundamental issue in the theory of continuous stochastic process is the interpretation of multiplicative white noise, which is often referred to as the Itô-Stratonovich dilemma. From a physical perspective, this reflects the need to introduce additional constraints in order to specify the nature of the noise, whereas from a mathematical perspective it reflects an ambiguity in the formulation of stochastic differential equations (SDEs). Recently, we have identified a mechanism for obtaining an Itô SDE based on a form of temporal disorder. Motivated by switching processes in molecular biology, we considered a Brownian particle that randomly switches between two distinct conformational states with different diffusivities. In each state, the particle undergoes normal diffusion (additive noise) so there is no ambiguity in the interpretation of the noise. However, if the switching rates depend on position, then in the fast switching limit one obtains Brownian motion with a space-dependent diffusivity of the Itô form. In this paper, we extend our theory to include colored additive noise. We show that the nature of the effective multiplicative noise process obtained by taking both the white-noise limit (κ →0 ) and fast switching limit (ɛ →0 ) depends on the order the two limits are taken. If the white-noise limit is taken first, then we obtain Itô, and if the fast switching limit is taken first, then we obtain Stratonovich. Moreover, the form of the effective diffusion coefficient differs in the two cases. The latter result holds even in the case of space-independent transition rates, where one obtains additive noise processes with different diffusion coefficients. Finally, we show that yet another form of multiplicative noise is obtained in the simultaneous limit ɛ ,κ →0 with ɛ /κ2 fixed.

  18. P3a from white noise.

    Science.gov (United States)

    Frank, David W; Yee, Ryan B; Polich, John

    2012-08-01

    P3a and P3b event-related brain potentials (ERPs) were elicited with an auditory three-stimulus (target, distracter, and standard) discrimination task in which subjects responded only to the target. Distracter stimuli consisted of white noise or novel sounds with stimulus characteristics perceptually matched. Target/standard discrimination difficulty was manipulated by varying target/standard pitch differences to produce relatively easy, medium, and hard tasks. Error rate and response time increased with increases in task difficulty. P3a was larger for the white noise compared to novel sounds, maximum over the central/parietal recording sites, and did not differ in size across difficulty levels. P3b was unaffected by distracter type, decreased as task difficulty increased, and maximum over the parietal recording sites. The findings indicate that P3a from white noise is robust and should be useful for applied studies as it removes stimulus novelty variability. Theoretical perspectives are discussed. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Theory And Working Of Noise And Vibration

    International Nuclear Information System (INIS)

    Jeong, Il Rok

    1988-09-01

    This book deals with theory of noise including physical property of noise like term and characteristic of sound, occurrence of sound, characteristic of noise pollution and main cause of occurrence of noise, technique of prevention of noise with noise reduction, construction guide for prevention of noise, and measure of interior noise. It also has the theory of vibration such as an introduction of vibration, and technology of prevention of vibration, official test method of environmental pollution, and summary of protection of the environment.

  20. Quantum noise and stochastic reduction

    International Nuclear Information System (INIS)

    Brody, Dorje C; Hughston, Lane P

    2006-01-01

    In standard nonrelativistic quantum mechanics the expectation of the energy is a conserved quantity. It is possible to extend the dynamical law associated with the evolution of a quantum state consistently to include a nonlinear stochastic component, while respecting the conservation law. According to the dynamics thus obtained, referred to as the energy-based stochastic Schroedinger equation, an arbitrary initial state collapses spontaneously to one of the energy eigenstates, thus describing the phenomenon of quantum state reduction. In this paper, two such models are investigated: one that achieves state reduction in infinite time and the other in finite time. The properties of the associated energy expectation process and the energy variance process are worked out in detail. By use of a novel application of a nonlinear filtering method, closed-form solutions-algebraic in character and involving no integration-are obtained of both these models. In each case, the solution is expressed in terms of a random variable representing the terminal energy of the system and an independent noise process. With these solutions at hand it is possible to simulate explicitly the dynamics of the quantum states of complicated physical systems

  1. Road traffic noise: self-reported noise annoyance versus GIS modelled road traffic noise exposure.

    Science.gov (United States)

    Birk, Matthias; Ivina, Olga; von Klot, Stephanie; Babisch, Wolfgang; Heinrich, Joachim

    2011-11-01

    self-reported road traffic noise annoyance is commonly used in epidemiological studies for assessment of potential health effects. Alternatively, some studies have used geographic information system (GIS) modelled exposure to road traffic noise as an objective parameter. The aim of this study was to analyse the association between noise exposure due to neighbouring road traffic and the noise annoyance of adults, taking other determinants into consideration. parents of 951 Munich children from the two German birth cohorts GINIplus and LISAplus reported their annoyance due to road traffic noise at home. GIS modelled road traffic noise exposure (L(den), maximum within a 50 m buffer) from the noise map of the city of Munich was available for all families. GIS-based calculated distance to the closest major road (≥10,000 vehicles per day) and questionnaire based-information about family income, parental education and the type of the street of residence were explored for their potential influence. An ordered logit regression model was applied. The noise levels (L(den)) and the reported noise annoyance were compared with an established exposure-response function. the correlation between noise annoyance and noise exposure (L(den)) was fair (Spearman correlation r(s) = 0.37). The distance to a major road and the type of street were strong predictors for the noise annoyance. The annoyance modelled by the established exposure-response function and that estimated by the ordered logit model were moderately associated (Pearson's correlation r(p) = 0.50). road traffic noise annoyance was associated with GIS modelled neighbouring road traffic noise exposure (L(den)). The distance to a major road and the type of street were additional explanatory factors of the noise annoyance appraisal.

  2. Spider Vein Removal

    Science.gov (United States)

    Spider veins: How are they removed? I have spider veins on my legs. What options are available ... M.D. Several options are available to remove spider veins — thin red lines or weblike networks of ...

  3. Nuisance Caused by Aircraft Noise in the Vicinity of Tehran International Airport

    Directory of Open Access Journals (Sweden)

    Stan Frost

    1999-03-01

    Full Text Available Noise measurement and social questionnaire surveys in three residential areas around Mehrabad International Airport (Tehran, Iran were based upon randomly selected dwellings in each area. A total of 193 individuals responded and many are annoyed and dissatisfied with aircraft noise and in consequence they would like to move. Aircraft noise is the strongest negative environmental factor affecting the residents in the vicinity of Mehrabad Airport and it could be a hazard for their health.

  4. 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

  5. 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.

  6. Identification and Filtering of Uncharacteristic Noise in the CMS Hadron Calorimeter

    CERN Document Server

    Chatrchyan, S; Sirunyan, A M; Adam, W; Arnold, B; Bergauer, H; Bergauer, T; Dragicevic, M; Eichberger, M; Erö, J; Friedl, M; Frühwirth, R; Ghete, V M; Hammer, J; Hänsel, S; Hoch, M; Hörmann, N; Hrubec, J; Jeitler, M; Kasieczka, G; Kastner, K; Krammer, M; Liko, D; Magrans de Abril, I; Mikulec, I; Mittermayr, F; Neuherz, B; Oberegger, M; Padrta, M; Pernicka, M; Rohringer, H; Schmid, S; Schöfbeck, R; Schreiner, T; Stark, R; Steininger, H; Strauss, J; Taurok, A; Teischinger, F; Themel, T; Uhl, D; Wagner, P; Waltenberger, W; Walzel, G; Widl, E; Wulz, C E; Chekhovsky, V; Dvornikov, O; Emeliantchik, I; Litomin, A; Makarenko, V; Marfin, I; Mossolov, V; Shumeiko, N; Solin, A; Stefanovitch, R; Suarez Gonzalez, J; Tikhonov, A; Fedorov, A; Karneyeu, A; Korzhik, M; Panov, V; Zuyeuski, R; Kuchinsky, P; Beaumont, W; Benucci, L; Cardaci, M; De Wolf, E A; Delmeire, E; Druzhkin, D; Hashemi, M; Janssen, X; Maes, T; Mucibello, L; Ochesanu, S; Rougny, R; Selvaggi, M; Van Haevermaet, H; Van Mechelen, P; Van Remortel, N; Adler, V; Beauceron, S; Blyweert, S; D'Hondt, J; De Weirdt, S; Devroede, O; Heyninck, J; Kalogeropoulos, A; Maes, J; Maes, M; Mozer, M U; Tavernier, S; Van Doninck, W; Van Mulders, P; Villella, I; Bouhali, O; Chabert, E C; Charaf, O; Clerbaux, B; De Lentdecker, G; Dero, V; Elgammal, S; Gay, A P R; Hammad, G H; Marage, P E; Rugovac, S; Vander Velde, C; Vanlaer, P; Wickens, J; Grunewald, M; Klein, B; Marinov, A; Ryckbosch, D; Thyssen, F; Tytgat, M; Vanelderen, L; Verwilligen, P; Basegmez, S; Bruno, G; Caudron, J; Delaere, C; Demin, P; Favart, D; Giammanco, A; Grégoire, G; Lemaitre, V; Militaru, O; Ovyn, S; Piotrzkowski, K; Quertenmont, L; Schul, N; Beliy, N; Daubie, E; Alves, G A; Pol, M E; Souza, M H G; Carvalho, W; De Jesus Damiao, D; De Oliveira Martins, C; Fonseca De Souza, S; Mundim, L; Oguri, V; Santoro, A; Silva Do Amaral, S M; Sznajder, A; Fernandez Perez Tomei, T R; Ferreira Dias, M A; Gregores, E M; Novaes, S F; Abadjiev, K; Anguelov, T; Damgov, J; Darmenov, N; Dimitrov, L; Genchev, V; Iaydjiev, P; Piperov, S; Stoykova, S; Sultanov, G; Trayanov, R; Vankov, I; Dimitrov, A; Dyulendarova, M; Kozhuharov, V; Litov, L; Marinova, E; Mateev, M; Pavlov, B; Petkov, P; Toteva, Z; Chen, G M; Chen, H S; Guan, W; Jiang, C H; Liang, D; Liu, B; Meng, X; Tao, J; Wang, J; Wang, Z; Xue, Z; Zhang, Z; Ban, Y; Cai, J; Ge, Y; Guo, S; Hu, Z; Mao, Y; Qian, S J; Teng, H; Zhu, B; Avila, C; Baquero Ruiz, M; Carrillo Montoya, C A; Gomez, A; Gomez Moreno, B; Ocampo Rios, A A; Osorio Oliveros, A F; Reyes Romero, D; Sanabria, J C; Godinovic, N; Lelas, K; Plestina, R; Polic, D; Puljak, I; Antunovic, Z; Dzelalija, M; Brigljevic, V; Duric, S; Kadija, K; Morovic, S; Fereos, R; Galanti, M; Mousa, J; Papadakis, A; Ptochos, F; Razis, P A; Tsiakkouri, D; Zinonos, Z; Hektor, A; Kadastik, M; Kannike, K; Müntel, M; Raidal, M; Rebane, L; Anttila, E; Czellar, S; Härkönen, J; Heikkinen, A; Karimäki, V; Kinnunen, R; Klem, J; Kortelainen, M J; Lampén, T; Lassila-Perini, K; Lehti, S; Lindén, T; Luukka, P; Mäenpää, T; Nysten, J; Tuominen, E; Tuominiemi, J; Ungaro, D; Wendland, L; Banzuzi, K; Korpela, A; Tuuva, T; Nedelec, P; Sillou, D; Besancon, M; Chipaux, R; Dejardin, M; Denegri, D; Descamps, J; Fabbro, B; Faure, J L; Ferri, F; Ganjour, S; Gentit, F X; Givernaud, A; Gras, P; Hamel de Monchenault, G; Jarry, P; Lemaire, M C; Locci, E; Malcles, J; Marionneau, M; Millischer, L; Rander, J; Rosowsky, A; Rousseau, D; Titov, M; Verrecchia, P; Baffioni, S; Bianchini, L; Bluj, M; Busson, P; Charlot, C; Dobrzynski, L; Granier de Cassagnac, R; Haguenauer, M; Miné, P; Paganini, P; Sirois, Y; Thiebaux, C; Zabi, A; Agram, J L; Besson, A; Bloch, D; Bodin, D; Brom, J M; Conte, E; Drouhin, F; Fontaine, J C; Gelé, D; Goerlach, U; Gross, L; Juillot, P; Le Bihan, A C; Patois, Y; Speck, J; Van Hove, P; Baty, C; Bedjidian, M; Blaha, J; Boudoul, G; Brun, H; Chanon, N; Chierici, R; Contardo, D; Depasse, P; Dupasquier, T; El Mamouni, H; Fassi, F; Fay, J; Gascon, S; Ille, B; Kurca, T; Le Grand, T; Lethuillier, M; 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Ignatenko, M; Jarvis, C; Mumford, J; Plager, C; Rakness, G; Schlein, P; Tucker, J; Valuev, V; Wallny, R; Yang, X; Babb, J; Bose, M; Chandra, A; Clare, R; Ellison, J A; Gary, J W; Hanson, G; Jeng, G Y; Kao, S C; Liu, F; Liu, H; Luthra, A; Nguyen, H; Pasztor, G; Satpathy, A; Shen, B C; Stringer, R; Sturdy, J; Sytnik, V; Wilken, R; Wimpenny, S; Branson, J G; Dusinberre, E; Evans, D; Golf, F; Kelley, R; Lebourgeois, M; Letts, J; Lipeles, E; Mangano, B; Muelmenstaedt, J; Norman, M; Padhi, S; Petrucci, A; Pi, H; Pieri, M; Ranieri, R; Sani, M; Sharma, V; Simon, S; Würthwein, F; Yagil, A; Campagnari, C; D'Alfonso, M; Danielson, T; Garberson, J; Incandela, J; Justus, C; Kalavase, P; Koay, S A; Kovalskyi, D; Krutelyov, V; Lamb, J; Lowette, S; Pavlunin, V; Rebassoo, F; Ribnik, J; Richman, J; Rossin, R; Stuart, D; To, W; Vlimant, J R; Witherell, M; Apresyan, A; Bornheim, A; Bunn, J; Chiorboli, M; Gataullin, M; Kcira, D; Litvine, V; Ma, Y; Newman, H B; Rogan, C; Timciuc, V; Veverka, J; Wilkinson, R; Yang, Y; Zhang, L; Zhu, K; Zhu, R Y; Akgun, B; Carroll, R; Ferguson, T; Jang, D W; Jun, S Y; Paulini, M; Russ, J; Terentyev, N; Vogel, H; Vorobiev, I; Cumalat, J P; Dinardo, M E; Drell, B R; Ford, W T; Heyburn, B; Luiggi Lopez, E; Nauenberg, U; Stenson, K; Ulmer, K; Wagner, S R; Zang, S L; Agostino, L; Alexander, J; Blekman, F; Cassel, D; Chatterjee, A; Das, S; Gibbons, L K; Heltsley, B; Hopkins, W; Khukhunaishvili, A; Kreis, B; Kuznetsov, V; Patterson, J R; Puigh, D; Ryd, A; Shi, X; Stroiney, S; Sun, W; Teo, W D; Thom, J; Vaughan, J; Weng, Y; Wittich, P; Beetz, C P; Cirino, G; Sanzeni, C; Winn, D; Abdullin, S; Afaq, M A; Albrow, M; Ananthan, B; Apollinari, G; Atac, M; Badgett, W; Bagby, L; Bakken, J A; Baldin, B; Banerjee, S; Banicz, K; Bauerdick, L A T; Beretvas, A; Berryhill, J; Bhat, P C; Biery, K; Binkley, M; Bloch, I; Borcherding, F; Brett, A M; Burkett, K; Butler, J N; Chetluru, V; Cheung, H W K; Chlebana, F; Churin, I; Cihangir, S; Crawford, M; Dagenhart, W; Demarteau, M; Derylo, G; Dykstra, D; Eartly, D P; Elias, J E; Elvira, V D; Evans, D; Feng, L; Fischler, M; Fisk, I; Foulkes, S; Freeman, J; Gartung, P; Gottschalk, E; Grassi, T; Green, D; Guo, Y; Gutsche, O; Hahn, A; Hanlon, J; Harris, R M; Holzman, B; Howell, J; Hufnagel, D; James, E; Jensen, H; Johnson, M; Jones, C D; Joshi, U; Juska, E; Kaiser, J; Klima, B; Kossiakov, S; Kousouris, K; Kwan, S; Lei, C M; Limon, P; Lopez Perez, J A; Los, S; Lueking, L; Lukhanin, G; Lusin, S; Lykken, J; Maeshima, K; Marraffino, J M; Mason, D; McBride, P; Miao, T; Mishra, K; Moccia, S; Mommsen, R; Mrenna, S; Muhammad, A S; Newman-Holmes, C; Noeding, C; O'Dell, V; Prokofyev, O; Rivera, R; Rivetta, C H; Ronzhin, A; Rossman, P; Ryu, S; Sekhri, V; Sexton-Kennedy, E; Sfiligoi, I; Sharma, S; Shaw, T M; Shpakov, D; Skup, E; Smith, R P; Soha, A; Spalding, W J; Spiegel, L; Suzuki, I; Tan, P; Tanenbaum, W; Tkaczyk, S; Trentadue, R; Uplegger, L; Vaandering, E W; Vidal, R; Whitmore, J; Wicklund, E; Wu, W; Yarba, J; Yumiceva, F; Yun, J C; Acosta, D; Avery, P; Barashko, V; Bourilkov, D; Chen, M; Di Giovanni, G P; Dobur, D; Drozdetskiy, A; Field, R D; Fu, Y; Furic, I K; Gartner, J; Holmes, D; Kim, B; Klimenko, S; Konigsberg, J; Korytov, A; Kotov, K; Kropivnitskaya, A; Kypreos, T; Madorsky, A; Matchev, K; Mitselmakher, G; Pakhotin, Y; Piedra Gomez, J; Prescott, C; Rapsevicius, V; Remington, R; Schmitt, M; Scurlock, B; Wang, D; Yelton, J; Ceron, C; Gaultney, V; Kramer, L; Lebolo, L M; Linn, S; Markowitz, P; Martinez, G; Rodriguez, J L; Adams, T; Askew, A; Baer, H; Bertoldi, M; Chen, J; Dharmaratna, W G D; Gleyzer, S V; Haas, J; Hagopian, S; Hagopian, V; Jenkins, M; Johnson, K F; Prettner, E; Prosper, H; Sekmen, S; Baarmand, M M; Guragain, S; Hohlmann, M; Kalakhety, H; Mermerkaya, H; Ralich, R; Vodopiyanov, I; Abelev, B; Adams, M R; Anghel, I M; Apanasevich, L; Bazterra, V E; Betts, R R; Callner, J; Castro, M A; Cavanaugh, R; Dragoiu, C; Garcia-Solis, E J; Gerber, C E; Hofman, D J; Khalatian, S; Mironov, C; Shabalina, E; Smoron, A; Varelas, N; Akgun, U; Albayrak, E A; Ayan, A S; Bilki, B; Briggs, R; Cankocak, K; Chung, K; Clarida, W; Debbins, P; Duru, F; Ingram, F D; Lae, C K; McCliment, E; Merlo, J P; Mestvirishvili, A; Miller, M J; Moeller, A; Nachtman, J; Newsom, C R; Norbeck, E; Olson, J; Onel, Y; Ozok, F; Parsons, J; Schmidt, I; Sen, S; Wetzel, J; Yetkin, T; Yi, K; Barnett, B A; Blumenfeld, B; Bonato, A; Chien, C Y; Fehling, D; Giurgiu, G; Gritsan, A V; Guo, Z J; Maksimovic, P; Rappoccio, S; Swartz, M; Tran, N V; Zhang, Y; Baringer, P; Bean, A; Grachov, O; Murray, M; Radicci, V; Sanders, S; Wood, J S; Zhukova, V; Bandurin, D; Bolton, T; Kaadze, K; Liu, A; Maravin, Y; Onoprienko, D; Svintradze, I; Wan, Z; Gronberg, J; Hollar, J; Lange, D; Wright, D; Baden, D; Bard, R; Boutemeur, M; Eno, S C; Ferencek, D; Hadley, N J; Kellogg, R G; Kirn, M; Kunori, S; Rossato, K; Rumerio, P; Santanastasio, F; Skuja, A; Temple, J; Tonjes, M B; Tonwar, S C; Toole, T; Twedt, E; Alver, B; Bauer, G; Bendavid, J; Busza, W; Butz, E; Cali, I A; Chan, M; D'Enterria, D; Everaerts, P; Gomez Ceballos, G; Hahn, K A; Harris, P; Jaditz, S; Kim, Y; Klute, M; Lee, Y J; Li, W; Loizides, C; Ma, T; Miller, M; Nahn, S; Paus, C; Roland, C; Roland, G; Rudolph, M; Stephans, G; Sumorok, K; Sung, K; Vaurynovich, S; Wenger, E A; Wyslouch, B; Xie, S; Yilmaz, Y; Yoon, A S; Bailleux, D; Cooper, S I; Cushman, P; Dahmes, B; De Benedetti, A; Dolgopolov, A; Dudero, P R; Egeland, R; Franzoni, G; Haupt, J; Inyakin, A; Klapoetke, K; Kubota, Y; Mans, J; Mirman, N; Petyt, D; Rekovic, V; Rusack, R; Schroeder, M; Singovsky, A; Zhang, J; Cremaldi, L M; Godang, R; Kroeger, R; Perera, L; Rahmat, R; Sanders, D A; Sonnek, P; Summers, D; Bloom, K; Bockelman, B; Bose, S; Butt, J; Claes, D R; Dominguez, A; Eads, M; Keller, J; Kelly, T; Kravchenko, I; Lazo-Flores, J; Lundstedt, C; Malbouisson, H; Malik, S; Snow, G R; Baur, U; Iashvili, I; Kharchilava, A; Kumar, A; Smith, K; Strang, M; Alverson, G; Barberis, E; Boeriu, O; Eulisse, G; Govi, G; McCauley, T; Musienko, Y; Muzaffar, S; Osborne, I; Paul, T; Reucroft, S; Swain, J; Taylor, L; Tuura, L; Anastassov, A; Gobbi, B; Kubik, A; Ofierzynski, R A; Pozdnyakov, A; Schmitt, M; Stoynev, S; Velasco, M; Won, S; Antonelli, L; Berry, D; Hildreth, M; Jessop, C; Karmgard, D J; Kolberg, T; Lannon, K; Lynch, S; Marinelli, N; Morse, D M; Ruchti, R; Slaunwhite, J; Warchol, J; Wayne, M; Bylsma, B; Durkin, L S; Gilmore, J; Gu, J; Killewald, P; Ling, T Y; Williams, G; Adam, N; Berry, E; Elmer, P; Garmash, A; Gerbaudo, D; Halyo, V; Hunt, A; Jones, J; Laird, E; Marlow, D; Medvedeva, T; Mooney, M; Olsen, J; Piroué, P; Stickland, D; Tully, C; Werner, J S; Wildish, T; Xie, Z; Zuranski, A; Acosta, J G; Bonnett Del Alamo, M; Huang, X T; Lopez, A; Mendez, H; Oliveros, S; Ramirez Vargas, J E; Santacruz, N; Zatzerklyany, A; Alagoz, E; Antillon, E; Barnes, V E; Bolla, G; Bortoletto, D; Everett, A; Garfinkel, A F; Gecse, Z; Gutay, L; Ippolito, N; Jones, M; Koybasi, O; Laasanen, A T; Leonardo, N; Liu, C; Maroussov, V; Merkel, P; Miller, D H; Neumeister, N; Sedov, A; Shipsey, I; Yoo, H D; Zheng, Y; Jindal, P; Parashar, N; Cuplov, V; Ecklund, K M; Geurts, F J M; Liu, J H; Maronde, D; Matveev, M; Padley, B P; Redjimi, R; Roberts, J; Sabbatini, L; Tumanov, A; Betchart, B; Bodek, A; Budd, H; Chung, Y S; de Barbaro, P; Demina, R; Flacher, H; Gotra, Y; Harel, A; Korjenevski, S; Miner, D C; Orbaker, D; Petrillo, G; Vishnevskiy, D; Zielinski, M; Bhatti, A; Demortier, L; Goulianos, K; Hatakeyama, K; Lungu, G; Mesropian, C; Yan, M; Atramentov, O; Bartz, E; Gershtein, Y; Halkiadakis, E; Hits, D; Lath, A; Rose, K; Schnetzer, S; Somalwar, S; Stone, R; Thomas, S; Watts, T L; Cerizza, G; Hollingsworth, M; Spanier, S; Yang, Z C; York, A; Asaadi, J; Aurisano, A; Eusebi, R; Golyash, A; Gurrola, A; Kamon, T; Nguyen, C N; Pivarski, J; Safonov, A; Sengupta, S; Toback, D; Weinberger, M; Akchurin, N; Berntzon, L; Gumus, K; Jeong, C; Kim, H; Lee, S W; Popescu, S; Roh, Y; Sill, A; Volobouev, I; Washington, E; Wigmans, R; Yazgan, E; Engh, D; Florez, C; Johns, W; Pathak, S; Sheldon, P; Andelin, D; Arenton, M W; Balazs, M; Boutle, S; Buehler, M; Conetti, S; Cox, B; Hirosky, R; Ledovskoy, A; Neu, C; Phillips II, D; Ronquest, M; Yohay, R; Gollapinni, S; Gunthoti, K; Harr, R; Karchin, P E; Mattson, M; Sakharov, A; Anderson, M; Bachtis, M; Bellinger, J N; Carlsmith, D; Crotty, I; Dasu, S; Dutta, S; Efron, J; Feyzi, F; Flood, K; Gray, L; Grogg, K S; Grothe, M; Hall-Wilton, R; Jaworski, M; Klabbers, P; Klukas, J; Lanaro, A; Lazaridis, C; Leonard, J; Loveless, R; Magrans de Abril, M; Mohapatra, A; Ott, G; Polese, G; Reeder, D; Savin, A; Smith, W H; Sourkov, A; Swanson, J; Weinberg, M; Wenman, D; Wensveen, M; White, A

    2010-01-01

    Commissioning studies of the CMS hadron calorimeter have identified sporadic uncharacteristic noise and a small number of malfunctioning calorimeter channels. Algorithms have been developed to identify and address these problems in the data. The methods have been tested on cosmic ray muon data, calorimeter noise data, and single beam data collected with CMS in 2008. The noise rejection algorithms can be applied to LHC collision data at the trigger level or in the offline analysis. The application of the algorithms at the trigger level is shown to remove 90% of noise events with fake missing transverse energy above 100 GeV, which is sufficient for the CMS physics trigger operation.

  7. The importance of railway noise in France

    CERN Document Server

    Maurin, M

    1979-01-01

    A national survey on environmental nuisances due to all forms of transport was made in France during 1977. From among the data gathered, it is possible to extract results concerning the impact of nuisance due to railways, partly from results of questionnaires and partly from results of acoustical measurements. Interviews and measurements were made in several towns, at randomly selected dwellings. Rail and air transport noise nuisance impacts appeared to be of comparable importance, with that of road transport very much larger than either. (0 refs).

  8. Influence of Spatial and Chromatic Noise on Luminance Discrimination.

    Science.gov (United States)

    Miquilini, Leticia; Walker, Natalie A; Odigie, Erika A; Guimarães, Diego Leite; Salomão, Railson Cruz; Lacerda, Eliza Maria Costa Brito; Cortes, Maria Izabel Tentes; de Lima Silveira, Luiz Carlos; Fitzgerald, Malinda E C; Ventura, Dora Fix; Souza, Givago Silva

    2017-12-05

    Pseudoisochromatic figures are designed to base discrimination of a chromatic target from a background solely on the chromatic differences. This is accomplished by the introduction of luminance and spatial noise thereby eliminating these two dimensions as cues. The inverse rationale could also be applied to luminance discrimination, if spatial and chromatic noise are used to mask those cues. In this current study estimate of luminance contrast thresholds were conducted using a novel stimulus, based on the use of chromatic and spatial noise to mask the use of these cues in a luminance discrimination task. This was accomplished by presenting stimuli composed of a mosaic of circles colored randomly. A Landolt-C target differed from the background only by the luminance. The luminance contrast thresholds were estimated for different chromatic noise saturation conditions and compared to luminance contrast thresholds estimated using the same target in a non-mosaic stimulus. Moreover, the influence of the chromatic content in the noise on the luminance contrast threshold was also investigated. Luminance contrast threshold was dependent on the chromaticity noise strength. It was 10-fold higher than thresholds estimated from non-mosaic stimulus, but they were independent of colour space location in which the noise was modulated. The present study introduces a new method to investigate luminance vision intended for both basic science and clinical applications.

  9. Noise-induced chaos in a quadratically nonlinear oscillator

    International Nuclear Information System (INIS)

    Gan Chunbiao

    2006-01-01

    The present paper focuses on the noise-induced chaos in a quadratically nonlinear oscillator. Simple zero points of the stochastic Melnikov integral theoretically mean the necessary rising of noise-induced chaotic response in the system based on the stochastic Melnikov method. To quantify the noise-induced chaos, the boundary of the system's safe basin is firstly studied and it is shown to be incursively fractal when chaos arises. Three cases are considered in simulating the safe basin of the system, i.e., the system is excited only by the harmonic excitation, by both the harmonic and the Gaussian white noise excitations, and only by the Gaussian white noise excitation. Secondly, the leading Lyapunov exponent by Rosenstein's algorithm is shown to quantify the chaotic nature of the sample time series of the system. The results show that the boundary of the safe basin can also be fractal even if the system is excited only by the external Gaussian white noise. Most importantly, the almost-harmonic, the noise-induced chaotic and the thoroughly random responses can be found in the system

  10. 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.

  11. PLANNING YOUR REMOVALS

    CERN Multimedia

    Service déménagement; ST Division

    1999-01-01

    To give you better service and avoid lengthy delays, the Removals Service advises you to refrain from programming moves between 26 July and 3 September, as large-scale removals are already planned during this summer period.Thanking you in advance for your co-operation and understanding.Removals Service STTel. 74185 / Mobile 164017

  12. PROGRAMMING OFFICE REMOVALS

    CERN Multimedia

    Groupe ST-HM

    2000-01-01

    The Removals Service recommends you to plan your removals well in advance, taking into account the fact that the Transport and Handling Group’s main priority remains the dismantling of LEP and the installation of the LHC. The requests can be made by: http://st.web.cern.ch/st/hm/removal/DEMEE.HTM Thank you for your cooperation.

  13. Quantum optics in multiple scattering random media

    DEFF Research Database (Denmark)

    Lodahl, Peter; Lagendijk, Ad

    2005-01-01

    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......-tions that should be readily attainable experimentally is devised. Figure 1. Inverse total transmission of shot noise (left) and technical noise (right) as a function of the thickness of the ran-dom medium. The experimental data are well explained by theory (curves). [1] J. Tworzydlo and C.W.J. Beenakker, Phys. Rev...

  14. A Hybrid Method of medical Image Restoration with Gaussian and Impulsive Noise; Un Metodo Hibrido de Restauracion de Images Medidas con Ruido Gausino e Impulsivo

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, M. G.; Vidal, V.; Verdu, G.; Mayo, P.; Rodenas, F.

    2011-07-01

    The noise removal techniques to restore noisy images is currently an important issue, for example, medical images obtained by X-ray computed tomography in noise due to the use of a small number of projections present noise of different types. In this paper we analyze and evaluate two techniques that separately each behaves efficiently for the removal of Gaussian and impulsive noise respectively, and combined to form a hybrid approach obtains very good performance with respect to quality in most different types of noise.

  15. Prevalence of noise induced hearing loss in textile industries in ...

    African Journals Online (AJOL)

    This cross sectional study measured the prevalence of Noise Induced Hearing Loss (NIHL) in textile industries in Dar Es Salaam city and Morogoro municipality. Data were collected from 125 employees randomly selected from each of the textile factory mill in each region through structured questionnaires and audiogram ...

  16. Low noise constant current source for bias dependent noise measurements

    International Nuclear Information System (INIS)

    Talukdar, D.; Bose, Suvendu; Bardhan, K. K.; Chakraborty, R. K.

    2011-01-01

    A low noise constant current source used for measuring the 1/f noise in disordered systems in ohmic as well as nonohmic regime is described. The source can supply low noise constant current starting from as low as 1 μA to a few tens of milliampere with a high voltage compliance limit of around 20 V. The constant current source has several stages, which can work in a standalone manner or together to supply the desired value of load current. The noise contributed by the current source is very low in the entire current range. The fabrication of a low noise voltage preamplifier modified for bias dependent noise measurements and based on the existing design available in the MAT04 data sheet is also described.

  17. The diversity and unit of reactor noise theory

    Science.gov (United States)

    Kuang, Zhifeng

    The study of reactor noise theory concerns questions about cause and effect relationships, and utilisation of random noise in nuclear reactor systems. The diversity of reactor noise theory arises from the variety of noise sources, the various mathematical treatments applied and various practical purposes. The neutron noise in zero- energy systems arises from the fluctuations in the number of neutrons per fission, the time between nuclear events, and the type of reactions. It can be used to evaluate system parameters. The mathematical treatment is based on the master equation of stochastic branching processes. The noise in power reactor systems is given rise by random processes of technological origin such as vibration of mechanical parts, boiling of the coolant, fluctuations of temperature and pressure. It can be used to monitor reactor behaviour with the possibility of detecting malfunctions at an early stage. The mathematical treatment is based on the Langevin equation. The unity of reactor noise theory arises from the fact that useful information from noise is embedded in the second moments of random variables, which lends the possibility of building up a unified mathematical description and analysis of the various reactor noise sources. Exploring such possibilities is the main subject among the three major topics reported in this thesis. The first subject is within the zero power noise in steady media, and we reported on the extension of the existing theory to more general cases. In Paper I, by use of the master equation approach, we have derived the most general Feynman- and Rossi-alpha formulae so far by taking the full joint statistics of the prompt and all the six groups of delayed neutron precursors, and a multiple emission source into account. The involved problems are solved with a combination of effective analytical techniques and symbolic algebra codes (Mathematica). Paper II gives a numerical evaluation of these formulae. An assessment of the

  18. Low-frequency flux noise in YBCO dc SQUIDs cooled in static magnetic fields

    International Nuclear Information System (INIS)

    Sager, M.P.; Bindslev Hansen, J.; Petersen, P.R.E.; Holst, T.; Shen, Y.Q.

    1999-01-01

    The low-frequency flux noise in bicrystal and step-edge YBa 2 Cu 3 O x dc SQUIDs has been investigated. The width, w, of the superconducting strips forming the SQUID frame was varied from 4 to 42 μm. The SQUIDs were cooled in static magnetic fields up to 150 μT. Two types of low-frequency noise dominated, namely 1/f-like noise and random telegraph noise giving a Lorentzian frequency spectrum. The 1/f noise performance of the w = 4, 6 and 7 μm SQUIDs was almost identical, while the SQUIDs with w = 22 and 42 μm showed an order of magnitude higher noise level. Our analysis of the data suggests an exponential increase of the 1/f noise versus the cooling field, exhibiting a characteristic magnetic field around 40 μT. (author)

  19. The Protective Effect of Conditioning on Noise-Induced Hearing Loss Is Frequency-Dependent

    Directory of Open Access Journals (Sweden)

    Akram Pourbakht

    2012-10-01

    Full Text Available We compared the extent of temporary threshold shift (TTS and hair cell loss following high level 4 kHz noise exposure with those preconditioned with moderate level 1 and 4 kHz octave band noise. Fifteen Male albino guinea pigs (300- 350 g in weight were randomly allocated into three groups: those exposed to 4 kHz octave band noise at 102 dB SPL (group 1, n=5; those conditioned with 1 kHz octave band noise at 85 dB SPL, 6 hours per day for 5 days, then exposed to noise (group 2, n=5; those conditioned with 4 kHz octave band noise at 85 dB SPL, then exposed to noise (group 3, n=5. An hour and one week after noise exposure, threshold shifts were evaluated by auditory-evoked brainstem response (ABR and then animals were euthanized for histological evaluation. We found that TTS and cochlear damage caused by noise exposure were significantly reduced by 1 kHz and 4 kHz conditioning (P<0.001. We also showed that 4 kHz protocol attenuates noise- induced TTS but no significant TTS reduction occurred by 1 kHz conditioning. Both protocol protected noise-induced cochlear damage. We concluded that lower tone conditioning could not protect against higher tone temporary noise-induced hearing loss, thus conditioning is a local acting and frequency-dependent phenomenon.

  20. Investigation of noise in gear transmissions by the method of mathematical smoothing of experiments

    Science.gov (United States)

    Sheftel, B. T.; Lipskiy, G. K.; Ananov, P. P.; Chernenko, I. K.

    1973-01-01

    A rotatable central component smoothing method is used to analyze rotating gear noise spectra. A matrix is formulated in which the randomized rows correspond to various tests and the columns to factor values. Canonical analysis of the obtained regression equation permits the calculation of optimal speed and load at a previous assigned noise level.