WorldWideScience

Sample records for background noise

  1. Background sound levels and wind turbine noise

    International Nuclear Information System (INIS)

    This paper reviewed the regulators' approach to the challenge of establishing sound level limits in wind turbine arrays that allow for variations in background sound level with wind speed. Wind speed influences the amount of noise produced by wind turbines and also the noise associated with wind passing over terrain and through foliage. New guidelines by Ontario's Ministry of the Environment were discussed along with wind noise as a function of speed in remote locations having a variety of terrain and foliage types. It was concluded that wind induced noise can effectively mask the steady noise of wind turbine generators, especially during high wind conditions. The extent of wind induced noise depends on the local terrain, foliage and wind speed through vegetation. Masking wind turbine noise by wind induced noise in vegetation can be reduced during stable atmospheric conditions which are common at night. The extent of masking by wind induced noise depends on the level and characteristics of wind turbine noise and wind induced noise. 9 refs., 2 tabs., 2 figs

  2. Physiologic correlates to background noise acceptance

    Science.gov (United States)

    Tampas, Joanna; Harkrider, Ashley; Nabelek, Anna

    2001-05-01

    Acceptance of background noise can be evaluated by having listeners indicate the highest background noise level (BNL) they are willing to accept while following the words of a story presented at their most comfortable listening level (MCL). The difference between the selected MCL and BNL is termed the acceptable noise level (ANL). One of the consistent findings in previous studies of ANL is large intersubject variability in acceptance of background noise. This variability is not related to age, gender, hearing sensitivity, personality, type of background noise, or speech perception in noise performance. The purpose of the current experiment was to determine if individual differences in physiological activity measured from the peripheral and central auditory systems of young female adults with normal hearing can account for the variability observed in ANL. Correlations between ANL and various physiological responses, including spontaneous, click-evoked, and distortion-product otoacoustic emissions, auditory brainstem and middle latency evoked potentials, and electroencephalography will be presented. Results may increase understanding of the regions of the auditory system that contribute to individual noise acceptance.

  3. Speech Recognition in Natural Background Noise

    OpenAIRE

    Julien Meyer; Laure Dentel; Fanny Meunier

    2013-01-01

    In the real world, human speech recognition nearly always involves listening in background noise. The impact of such noise on speech signals and on intelligibility performance increases with the separation of the listener from the speaker. The present behavioral experiment provides an overview of the effects of such acoustic disturbances on speech perception in conditions approaching ecologically valid contexts. We analysed the intelligibility loss in spoken word lists with increasing listene...

  4. Background noise spectra of global seismic stations

    Energy Technology Data Exchange (ETDEWEB)

    Wada, M.M.; Claassen, J.P.

    1996-08-01

    Over an extended period of time station noise spectra were collected from various sources for use in estimating the detection and location performance of global networks of seismic stations. As the database of noise spectra enlarged and duplicate entries became available, an effort was mounted to more carefully select station noise spectra while discarding others. This report discusses the methodology and criteria by which the noise spectra were selected. It also identifies and illustrates the station noise spectra which survived the selection process and which currently contribute to the modeling efforts. The resulting catalog of noise statistics not only benefits those who model network performance but also those who wish to select stations on the basis of their noise level as may occur in designing networks or in selecting seismological data for analysis on the basis of station noise level. In view of the various ways by which station noise were estimated by the different contributors, it is advisable that future efforts which predict network performance have available station noise data and spectral estimation methods which are compatible with the statistics underlying seismic noise. This appropriately requires (1) averaging noise over seasonal and/or diurnal cycles, (2) averaging noise over time intervals comparable to those employed by actual detectors, and (3) using logarithmic measures of the noise.

  5. Urban background noise mapping: the general model

    NARCIS (Netherlands)

    Wei, W.; Botteldooren, D.; Renterghem, T. van; Hornikx, M.; Forssen, J.; Salomons, E.; Ogren, M.

    2014-01-01

    Surveys show that inhabitants of dwellings exposed to high noise levels benefit from having access to a quiet side. However, current practice in noise prediction often underestimates the noise levels at a shielded façade. Multiple reflections between façades in street canyons and inner yards are com

  6. Measurement of Acceptable Noise Level with Background Music

    OpenAIRE

    Ahn, Hyun-Jung; Bahng, Junghwa; Lee, Jae Hee

    2015-01-01

    Background and Objectives Acceptable noise level (ANL) is a measure of the maximum background noise level (BNL) that a person is willing to tolerate while following a target story. Although researchers have used various sources of target sound in ANL measures, a limited type of background noise has been used. Extending the previous study of Gordon-Hickey & Moore (2007), the current study determined the effect of music genre and tempo on ANLs as possible factors affecting ANLs. We also investi...

  7. Auditory intensity processing: Effect of MRI background noise.

    Science.gov (United States)

    Angenstein, Nicole; Stadler, Jörg; Brechmann, André

    2016-03-01

    Studies on active auditory intensity discrimination in humans showed equivocal results regarding the lateralization of processing. Whereas experiments with a moderate background found evidence for right lateralized processing of intensity, functional magnetic resonance imaging (fMRI) studies with background scanner noise suggest more left lateralized processing. With the present fMRI study, we compared the task dependent lateralization of intensity processing between a conventional continuous echo planar imaging (EPI) sequence with a loud background scanner noise and a fast low-angle shot (FLASH) sequence with a soft background scanner noise. To determine the lateralization of the processing, we employed the contralateral noise procedure. Linearly frequency modulated (FM) tones were presented monaurally with and without contralateral noise. During both the EPI and the FLASH measurement, the left auditory cortex was more strongly involved than the right auditory cortex while participants categorized the intensity of FM tones. This was shown by a strong effect of the additional contralateral noise on the activity in the left auditory cortex. This means a massive reduction in background scanner noise still leads to a significant left lateralized effect. This suggests that the reversed lateralization in fMRI studies with loud background noise in contrast to studies with softer background cannot be fully explained by the MRI background noise. PMID:26778471

  8. Comparison of Speech Perception in Background Noise with Acceptance of Background Noise in Aided and Unaided Conditions.

    Science.gov (United States)

    Nabelek, Anna K.; Tampas, Joanna W.; Burchfield, Samuel B.

    2004-01-01

    l, speech perception in noiseBackground noise is a significant factor influencing hearing-aid satisfaction and is a major reason for rejection of hearing aids. Attempts have been made by previous researchers to relate the use of hearing aids to speech perception in noise (SPIN), with an expectation of improved speech perception followed by an…

  9. Effects of road traffic background noise on judgments of individual airplane noises. Ph.D. Thesis

    Science.gov (United States)

    Powell, C. A.

    1979-01-01

    Two laboratory experiments were conducted to investigate the effects of road-traffic background noise on judgments of individual airplane flyover noises. In the first experiment, 27 subjects judged a set of 16 airplane flyover noises in the presence of traffic-noise sessions of 30-min duration consisting of the combinations of 3 traffic-noise types and 3 noise levels. In the second experiment, 24 subjects judged the same airplane flyover noises in the presence of traffic-noise sessions of 10-min duration consisting of the combinations of 2 traffic-noise types and 4 noise levels. In both experiments the airplane noises were judged less annoying in the presence of high traffic-noise levels than in the presence of low traffic-noise levels.

  10. Retinal Image Preprocessing: Background and Noise Segmentation

    OpenAIRE

    Usman Akram

    2012-01-01

    Retinal images are used for the automated screening and diagnosis of diabetic retinopathy. The retinal image quality must be improved for the detection of features and abnormalities and for this purpose preprocessing of retinal images is vital. In this paper, we present a novel automated approach for preprocessing of colored retinal images. The proposed technique improves the quality of input retinal image by separating the background and noisy area from the overall image. It contains coarse ...

  11. Retinal Image Preprocessing: Background and Noise Segmentation

    Directory of Open Access Journals (Sweden)

    Usman Akram

    2012-07-01

    Full Text Available Retinal images are used for the automated screening and diagnosis of diabetic retinopathy. The retinal image quality must be improved for the detection of features and abnormalities and for this purpose preprocessing of retinal images is vital. In this paper, we present a novel automated approach for preprocessing of colored retinal images. The proposed technique improves the quality of input retinal image by separating the background and noisy area from the overall image. It contains coarse segmentation and fine segmentation. Standard retinal images databases Diaretdb0, Diaretdb1, DRIVE and STARE are used to test the validation of our preprocessing technique. The experimental results show the validity of proposed preprocessing technique.

  12. 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.

  13. Interaction of Working Memory, Compressor Speed and Background Noise Characteristics

    OpenAIRE

    Ohlenforst, Barbara; MacDonald, Ewen; Souza, Pamela

    2014-01-01

    Previous studies have shown that individuals with poor working memory perform worse in speech recognition tests when fast compression release time is applied. However, it is not clear why this effect occurs only when modulations are present in the background noise. This study explored the relationship between working memory capacity, compression release time and characteristics of the background noise. This relationship is important to understand because the majority of everyday listening sit...

  14. Background Noise Contributes to Organic Solvent Induced Brain Dysfunction

    Directory of Open Access Journals (Sweden)

    O’neil W. Guthrie

    2016-01-01

    Full Text Available Occupational exposure to complex blends of organic solvents is believed to alter brain functions among workers. However, work environments that contain organic solvents are also polluted with background noise which raises the issue of whether or not the noise contributed to brain alterations. The purpose of the current study was to determine whether or not repeated exposure to low intensity noise with and without exposure to a complex blend of organic solvents would alter brain activity. Female Fischer344 rats served as subjects in these experiments. Asynchronous volume conductance between the midbrain and cortex was evaluated with a slow vertex recording technique. Subtoxic solvent exposure, by itself, had no statistically significant effects. However, background noise significantly suppressed brain activity and this suppression was exacerbated with solvent exposure. Furthermore, combined exposure produced significantly slow neurotransmission. These abnormal neurophysiologic findings occurred in the absence of hearing loss and detectable damage to sensory cells. The observations from the current experiment raise concern for all occupations where workers are repeatedly exposed to background noise or noise combined with organic solvents. Noise levels and solvent concentrations that are currently considered safe may not actually be safe and existing safety regulations have failed to recognize the neurotoxic potential of combined exposures.

  15. Background noise cancellation for improved acoustic detection of manatee vocalizations

    Science.gov (United States)

    Yan, Zheng; Niezrecki, Christopher; Beusse, Diedrich O.

    2005-06-01

    The West Indian manatee (Trichechus manatus latirostris) has become endangered partly because of an increase in the number of collisions with boats. A device to alert boaters of the presence of manatees, so that a collision can be avoided, is desired. A practical implementation of the technology is dependent on the hydrophone spacing and range of detection. These parameters are primarily dependent on the manatee vocalization strength, the decay of the signal's strength with distance, and the background noise levels. An efficient method to extend the detection range by using background noise cancellation is proposed in this paper. An adaptive line enhancer (ALE) that can detect and track narrow band signals buried in broadband noise is implemented to cancel the background noise. The results indicate that the ALE algorithm can efficiently extract the manatee calls from the background noise. The improved signal-to-noise ratio of the signal can be used to extend the range of detection of manatee vocalizations and reduce the false alarm and missing detection rate in their natural habitat. .

  16. Survey of noise exposure and background noise in call centers using headphones.

    Science.gov (United States)

    Trompette, N; Chatillon, J

    2012-01-01

    Call centers represent one of the fastest growing industries. However, there are health and safety hazards unique to this new industry. One of these potential hazards is hearing impairment caused by headsets. In this study, noise exposure assessment was performed at 21 call centers and for 117 operators. Although call center background noise does not contribute to noise exposure, it impacts working conditions and influences the headset volume setting. It was therefore measured at the same time as exposure to noise. Results revealed that although the risk of hearing impairment was generally low, exposure could exceed the European Union regulation upper and lower exposure action values. Besides exposure to noise, background noise levels are often high with regard to recommendations for office workers. Results are discussed and some recommendations are given, issued from on-site observations. Their application is intended to ensure the absence of excessive exposure to noise and improve acoustic comfort. PMID:22577858

  17. Background Noise Characteristics in the Western Part of Romania

    Science.gov (United States)

    Grecu, B.; Neagoe, C.; Tataru, D.; Stuart, G.

    2012-04-01

    The seismological database of the western part of Romania increased significantly during the last years, when 33 broadband seismic stations provided by SEIS-UK (10 CMG 40 T's - 30 s, 9 CMG 3T's - 120 s, 14 CMG 6T's - 30 s) were deployed in the western part of the country in July 2009 to operate autonomously for two years. These stations were installed within a joint project (South Carpathian Project - SCP) between University of Leeds, UK and National Institute for Earth Physics (NIEP), Romania that aimed at determining the lithospheric structure and geodynamical evolution of the South Carpathian Orogen. The characteristics of the background seismic noise recorded at the SCP broadband seismic network have been studied in order to identify the variations in background seismic noise as a function of time of day, season, and particular conditions at the stations. Power spectral densities (PSDs) and their corresponding probability density functions (PDFs) are used to characterize the background seismic noise. At high frequencies (> 1 Hz), seismic noise seems to have cultural origin, since notable variations between daytime and nighttime noise levels are observed at most of the stations. The seasonal variations are seen in the microseisms band. The noise levels increase during the winter and autumn months and decrease in summer and spring seasons, while the double-frequency peak shifts from lower periods in summer to longer periods in winter. The analysis of the probability density functions for stations located in different geologic conditions points out that the noise level is higher for stations sited on softer formations than those sited on hard rocks. Finally, the polarization analysis indicates that the main sources of secondary microseisms are found in the Mediterranean Sea and Atlantic Ocean.

  18. Interaction of Working Memory, Compressor Speed and Background Noise Characteristics

    DEFF Research Database (Denmark)

    Ohlenforst, Barbara; MacDonald, Ewen; Souza, Pamela

    Previous studies have shown that individuals with poor working memory perform worse in speech recognition tests when fast compression release time is applied. However, it is not clear why this effect occurs only when modulations are present in the background noise. This study explored the relatio...

  19. Improvement in the insensitivity of pulse amplifiers to background noise

    International Nuclear Information System (INIS)

    The level of background noise around certain reactors is often so great that the operation of pulse assemblies is strongly affected. A few practical precautions are described which make it possible to decrease the sensitivity to interference. Results obtained on two reactors, G1 and AQUILON, are described. (authors)

  20. Identification of simulated microcalcifications in white noise and mammographic backgrounds

    International Nuclear Information System (INIS)

    This work investigates human performance in discriminating between differently shaped simulated microcalcifications embedded in white noise or mammographic backgrounds. Human performance was determined through two alternative forced-choice (2-AFC) experiments. The signals used were computer-generated simple shapes that were designed such that they had equal signal energy. This assured equal detectability. For experiments involving mammographic backgrounds, signals were blurred to account for the imaging system modulation transfer function (MTF). White noise backgrounds were computer generated; anatomic background patches were extracted from normal mammograms. We compared human performance levels as a function of signal energy in the expected difference template. In the discrimination task, the expected difference template is the difference between the two signals shown. In white noise backgrounds, human performance in the discrimination task was degraded compared to the detection task. In mammographic backgrounds, human performance in the discrimination task exceeded that of the detection task. This indicates that human observers do not follow the optimum decision strategy of correlating the expected signal template with the image. Human observer performance was qualitatively reproduced by non-prewhitening with eye filter (NPWE) model observer calculations, in which spatial uncertainty was explicitly included by shifting the locations of the expected difference templates. The results indicate that human strategy in the discrimination task may be to match individual signal templates with the image individually, rather than to perform template matching between the expected difference template and the image

  1. Reproduction of Realistic Background Noise for Testing Telecommunications Devices

    DEFF Research Database (Denmark)

    Gil Corrales, Juan David; Song, Wookeun; MacDonald, Ewen

    2015-01-01

    A method for reproduction of sound, based on crosstalk cancellation using inverse filters, was implemented in the context of testing telecommunications devices. The effect of the regularization parameter, number of loudspeakers, type of background noise, and a technique to attenuate audible...... performance was equally good when using eight or four loudspeakers, and the reproduction method was shown to be robust for different program materials. The proposed technique to reduce audible artifacts increased the perceived similarity....

  2. Data Series Subtraction with Unknown and Unmodeled Background Noise

    Science.gov (United States)

    Vitale, Stefano; Congedo, Giuseppe; Dolesi, Rita; Ferroni, Valerio; Hueller, Mauro; Vetrugno, Daniele; Weber, William Joseph; Audley, Heather; Danzmann, Karsten; Diepholz, Ingo; Hewitson, Martin; Korsakova, Natalia; Ferraioli, Luigi; Gibert, Ferran; Karnesis, Nikolaos; Nofrarias, Miquel; Inchauspe, Henri; Plagnol, Eric; Jennrich, Oliver; McNamara, Paul W.; Armano, Michele; Thorpe, James Ira; Wass, Peter

    2014-01-01

    LISA Pathfinder (LPF), the precursor mission to a gravitational wave observatory of the European Space Agency, will measure the degree to which two test masses can be put into free fall, aiming to demonstrate a suppression of disturbance forces corresponding to a residual relative acceleration with a power spectral density (PSD) below (30 fm/sq s/Hz)(sup 2) around 1 mHz. In LPF data analysis, the disturbance forces are obtained as the difference between the acceleration data and a linear combination of other measured data series. In many circumstances, the coefficients for this linear combination are obtained by fitting these data series to the acceleration, and the disturbance forces appear then as the data series of the residuals of the fit. Thus the background noise or, more precisely, its PSD, whose knowledge is needed to build up the likelihood function in ordinary maximum likelihood fitting, is here unknown, and its estimate constitutes instead one of the goals of the fit. In this paper we present a fitting method that does not require the knowledge of the PSD of the background noise. The method is based on the analytical marginalization of the posterior parameter probability density with respect to the background noise PSD, and returns an estimate both for the fitting parameters and for the PSD. We show that both these estimates are unbiased, and that, when using averaged Welchs periodograms for the residuals, the estimate of the PSD is consistent, as its error tends to zero with the inverse square root of the number of averaged periodograms. Additionally, we find that the method is equivalent to some implementations of iteratively reweighted least-squares fitting. We have tested the method both on simulated data of known PSD and on data from several experiments performed with the LISA Pathfinder end-to-end mission simulator.

  3. Background Noise Reduction in Wind Tunnels using Adaptive Noise Cancellation and Cepstral Echo Removal Techniques for Microphone Array Applications

    OpenAIRE

    Spalt, Taylor B

    2010-01-01

    Two experiments were conducted to investigate Adaptive Noise Cancelling and Cepstrum echo removal post-processing techniques on acoustic data from a linear microphone array in an anechoic chamber. A point source speaker driven with white noise was used as the primary signal. The first experiment included a background speaker to provide interference noise at three different Signal-to-Noise Ratios to simulate noise propagating down a wind tunnel circuit. The second experiment contained only the...

  4. Influence of background noise on the performance in the odor sensitivity task: effects of noise type and extraversion.

    Science.gov (United States)

    Seo, Han-Seok; Hähner, Antje; Gudziol, Volker; Scheibe, Mandy; Hummel, Thomas

    2012-10-01

    Recent research demonstrated that background noise relative to silence impaired subjects' performance in a cognitively driven odor discrimination test. The current study aimed to investigate whether the background noise can also modulate performance in an odor sensitivity task that is less cognitively loaded. Previous studies have shown that the effect of background noise on task performance can be different in relation to degree of extraversion and/or type of noise. Accordingly, we wanted to examine whether the influence of background noise on the odor sensitivity task can be altered as a function of the type of background noise (i.e., nonverbal vs. verbal noise) and the degree of extraversion (i.e., introvert vs. extrovert group). Subjects were asked to conduct an odor sensitivity task in the presence of either nonverbal noise (e.g., party sound) or verbal noise (e.g., audio book), or silence. Overall, the subjects' mean performance in the odor sensitivity task was not significantly different across three auditory conditions. However, with regard to the odor sensitivity task, a significant interaction emerged between the type of background noise and the degree of extraversion. Specifically, verbal noise relative to silence significantly impaired or improved the performance of the odor sensitivity task in the introvert or extrovert group, respectively; the differential effect of introversion/extraversion was not observed in the nonverbal noise-induced task performance. In conclusion, our findings provide new empirical evidence that type of background noise and degree of extraversion play an important role in modulating the effect of background noise on subjects' performance in an odor sensitivity task. PMID:22941357

  5. Visual signal detection in structured backgrounds. II. Effects of contrast gain control, background variations, and white noise

    Science.gov (United States)

    Eckstein, M. P.; Ahumada, A. J. Jr; Watson, A. B.

    1997-01-01

    Studies of visual detection of a signal superimposed on one of two identical backgrounds show performance degradation when the background has high contrast and is similar in spatial frequency and/or orientation to the signal. To account for this finding, models include a contrast gain control mechanism that pools activity across spatial frequency, orientation and space to inhibit (divisively) the response of the receptor sensitive to the signal. In tasks in which the observer has to detect a known signal added to one of M different backgrounds grounds due to added visual noise, the main sources of degradation are the stochastic noise in the image and the suboptimal visual processing. We investigate how these two sources of degradation (contrast gain control and variations in the background) interact in a task in which the signal is embedded in one of M locations in a complex spatially varying background (structured background). We use backgrounds extracted from patient digital medical images. To isolate effects of the fixed deterministic background (the contrast gain control) from the effects of the background variations, we conduct detection experiments with three different background conditions: (1) uniform background, (2) a repeated sample of structured background, and (3) different samples of structured background. Results show that human visual detection degrades from the uniform background condition to the repeated background condition and degrades even further in the different backgrounds condition. These results suggest that both the contrast gain control mechanism and the background random variations degrade human performance in detection of a signal in a complex, spatially varying background. A filter model and added white noise are used to generate estimates of sampling efficiencies, an equivalent internal noise, an equivalent contrast-gain-control-induced noise, and an equivalent noise due to the variations in the structured background.

  6. Helicopter Rotor Noise Prediction: Background, Current Status, and Future Direction

    Science.gov (United States)

    Brentner, Kenneth S.

    1997-01-01

    Helicopter noise prediction is increasingly important. The purpose of this viewgraph presentation is to: 1) Put into perspective the recent progress; 2) Outline current prediction capabilities; 3) Forecast direction of future prediction research; 4) Identify rotorcraft noise prediction needs. The presentation includes an historical perspective, a description of governing equations, and the current status of source noise prediction.

  7. Minkowski maps: detection of diffuse signals with strong background noise

    Energy Technology Data Exchange (ETDEWEB)

    Klatt, Michael A.; Mecke, Klaus [Institut fuer Theoretische Physik, Universitaet Erlangen (Germany); ECAP, Universitaet Erlangen (Germany); Goering, Daniel [ECAP, Universitaet Erlangen (Germany); Stegmann, Christian [DESY (Germany); Universitaet Potsdam (Germany)

    2013-07-01

    A new technique based on the morphology of random fields is developed to detect non-Poisson features via structural deviations; for example for detection of spatially extended signals in count maps with high background noise. The morphometric analysis quantifies the structure of random fields by Minkowski functionals, which are powerful shape measures. Hadwiger's completeness theorem ensures that Minkowski functionals provide robust and comprehensive shape information and have short computation times. The joint probability distribution of all three Minkowski functionals is determined by a Monte-Carlo-algorithm for a Poisson random field. Common likelihood ratio methods are exclusively based on the number of excess counts and discard all further structure information. The analysis based on Minkowski functionals incorporates this additional geometric information in an unbiased analysis, i.e. not looking for an explicit shape but detecting any structural deviation. The non-Poisson features, e.g. sources, are visualized with Minkowski maps. The technique is designed to detect extended sources in γ-ray astronomy and is successfully applied to data of the H.E.S.S. experiment.

  8. The Impact of Listening Condition on Background Noise Acceptance for Young Adults with Normal Hearing

    Science.gov (United States)

    Gordon-Hickey, Susan; Moore, Robert E.; Estis, Julie M.

    2012-01-01

    Purpose: To evaluate the effect of different speech conditions on background noise acceptance. A total of 23 stimulus pairings, differing in primary talker gender (female, male, conventional), number of background talkers (1, 4, 12), and gender composition of the background noise (female, male, mixed) were used to evaluate background noise…

  9. The effects of background white noise on memory performance in inattentive school children

    OpenAIRE

    Söderlund, Göran BW; Sikström, Sverker; Loftesnes, Jan M; Sonuga-Barke, Edmund J.

    2010-01-01

    Background: Noise is typically conceived of as being detrimental for cognitive performance; however, a recent computational model based on the concepts of stochastic resonance and dopamine related internal noise postulates that a moderate amount of auditive noise benefit individuals in hypodopaminergic states. On the basis of this model we predicted that inattentive children would be enhanced by adding background white noise while attentive children’s performance would deteriorate...

  10. The effects of background white noise on memory performance in inattentive school children

    Directory of Open Access Journals (Sweden)

    Sikström Sverker

    2010-09-01

    Full Text Available Abstract Background Noise is typically conceived of as being detrimental for cognitive performance; however, a recent computational model based on the concepts of stochastic resonance and dopamine related internal noise postulates that a moderate amount of auditive noise benefit individuals in hypodopaminergic states. On the basis of this model we predicted that inattentive children would be enhanced by adding background white noise while attentive children's performance would deteriorate. Methods Fifty-one secondary school pupils carried out an episodic verbal free recall test in two noise conditions. In the high noise condition, verb-noun sentences were presented during auditory background noise (white noise, 78 dB, and in the low noise condition sentences were presented without noise. Results Exposure to background noise improved performance for inattentive children and worsened performance for attentive children and eliminated episodic memory differences between attentive and inattentive school children. Conclusions Consistent with the model, our data show that cognitive performance can be moderated by external background white noise stimulation in a non-clinical group of inattentive participants. This finding needs replicating in a larger sample using more noise levels but if replicated has great practical applications by offering a non-invasive way to improve school results in children with attentional problems.

  11. Background noise and its influence on the brain waves related to attention

    OpenAIRE

    Tristán Hernández, Edgar; Pavón García, Ignacio; López Navarro, Juan Manuel

    2013-01-01

    In this work, we present a study whose objective is to prove the influence of background noise produced inside university facilities on the brain waves related to attention processes. Recordings of background noise were carried out in study areas inside university facilities. Volunteers were asked to perform an attention test without any background noise but also while being exposed to the sound recordings, and their cerebral activity was recorded through electroencephalography (EEG). After t...

  12. An analysis of background noise in selected canyons of Los Alamos County

    Energy Technology Data Exchange (ETDEWEB)

    Huchton, K.; Koch, S.W.; Robinson, R.

    1997-10-01

    The authors recorded background noise levels in six canyons within Los Alamos County in order to establish a baseline for future comparisons and to discover what noises animals are exposed to. Noise level measurements were taken within each canyon, beginning at an established starting point and at one-mile intervals up to four miles. The primary source of noise above 55 dBA was vehicular traffic. One clap of thunder provided the highest recorded noise level (76 dBA). In general, the level of noise, once away from highways and parking lots, was well below 60 dBA.

  13. Background Noise Acceptance and Personality Factors Involved in Library Environment Choices by College Students

    Science.gov (United States)

    Gordon-Hickey, Susan; Lemley, Trey

    2012-01-01

    For decades, academic libraries made efforts to provide study environments differing in acoustic environment. The present study aimed to provide an evidence basis for this practice by comparing background noise acceptance and personality factors of two groups of college-aged students self identified as preferring quiet or background noise when…

  14. Reducing Background Noise Through a Stethoscope Cup Using Adaptive Filters

    OpenAIRE

    Hill, Bryce E.; Christensen, Douglas

    2010-01-01

    An adaptive filtering algorithm was used to test the validity of adaptively filtering respiratory signals recorded at the trachea with an external reference microphone. Two different setups were tested. The first used a microphone in open air, the second used a microphone that was housed inside a second stethoscope cup. The primary microphone was affixed to a phantom material. External sounds and music were played via aloud speaker to record additive noise data from within the stethoscope cup...

  15. Elimination of the Background Noise of the Decoded Image in Fresnel Zone Plate Scanning Holography

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A method of digitally high pass filtering in frequency domain is proposed to eliminate the background noise of the decoded image in Fresnel zone plate scanning holography. The high pass filter is designed as a circular stop, which should be suitable to suppressing the background noise significantly and remain much low frequency information of the object. The principle of high pass filtering is that the Fourier transform of the decoded image is multiplied with the high pass filter. Thus the frequency spectrum of the decoded image without the background noise is achieved. By inverse Fourier transform of the spectrum of the decoded image after multiplying operation, the decoded image without the background noise is obtained. Both of the computer simulations and the experimental results show that the contrast and the signal-to-noise ratio of the decoded image are significantly improved with digital filtering.

  16. Assessment of speech intelligibility in background noise and reverberation

    DEFF Research Database (Denmark)

    Nielsen, Jens Bo

    important deviation between the two new tests and the original HINT is a new procedure used for equalizing the intelligibility of the speech material during the development process. This procedure produces more accurately equalized sentences than achieved with the original HINT procedure. This study also......Reliable methods for assessing speech intelligibility are essential within hearing research, audiology, and related areas. Such methods can be used for obtaining a better understanding of how speech intelligibility is affected by, e.g., various environmental factors or different types of hearing...... impairment. In this thesis, two sentence-based tests for speech intelligibility in Danish were developed. The first test is the Conversational Language Understanding Evaluation (CLUE), which is based on the principles of the original American-English Hearing in Noise Test (HINT). The second test is a...

  17. Study of the background noise in microwave GaAsFET devices

    International Nuclear Information System (INIS)

    One of the most important properties of the gallium arsenide field effect transistor is its low noise figure in the microwave frequency range (approx. 1 dB, 4 GHz). The applications of this device in components and systems in the high frequency range require analysis of background noise in terms of basic static and dynamic properties of the device. The purpose of this paper is to review GaAsFET noise properties; from this review, a description of precise noise measurement techniques is made. Some experimental and theoretical results on the minimum noise figure are shown for several GaAsFET devices. (author)

  18. Background noise measurements on prototype of SNR 300 steam generator at Hengelo

    International Nuclear Information System (INIS)

    Acoustic noise amplitudes were measured in a 50 MW helical coil prototype of a steam generator mounted in the Hengelo test facility in a joint technical program betwen GE/DOE and TNO/NERATOOM. Background noise measurements were completed with test conditions ranging from quiescent (with no sodium or water flow) to high thermal power transfer from the sodium circuit to the water circuit. The acoustic noise pressure on the vessel wall was measured using externally mounted accelerometers. Data were obtained for the effect of sodium flow rate on the acoustic noise amplitude. A preliminary correlation was derived for the acoustic noise generated by nucleate boiling. Leak detection and location were demonstrated

  19. Study of the background noise in microwave GaAsFET devices

    Energy Technology Data Exchange (ETDEWEB)

    Serrano S, A. (Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, B.C. (Mexico))

    1984-01-01

    One of the most important properties of the gallium arsenide field effect transistor is its low noise figure in the microwave frequency range (approx. 1 dB, 4 GHz). The applications of this device in components and systems in the high frequency range require analysis of background noise in terms of basic static and dynamic properties of the device. The purpose of this paper is to review GaAsFET noise properties; from this review, a description of precise noise measurement techniques is made. Some experimental and theoretical results on the minimum noise figure are shown for several GaAsFET devices.

  20. Exploring the Relationship Between Working Memory, Compressor Speed, and Background Noise Characteristics

    DEFF Research Database (Denmark)

    Ohlenforst, Barbara; Souza, Pamela E.; MacDonald, Ewen

    2016-01-01

    Objectives: Previous work has shown that individuals with lower working memory demonstrate reduced intelligibility for speech processed with fast-acting compression amplification. This relationship has been noted in fluctuating noise, but the extent of noise modulation that must be present to...... elicit such an effect is unknown. This study expanded on previous study by exploring the effect of background noise modulations in relation to compression speed and working memory ability, using a range of signal to noise ratios. Design: Twenty-six older participants between ages 61 and 90 years were...... grouped by high or low working memory according to their performance on a reading span test. Speech intelligibility was measured for low-context sentences presented in background noise, where the noise varied in the extent of amplitude modulation. Simulated fast- or slowacting compression amplification...

  1. The Effects of Digital Noise Reduction on the Acceptance of Background Noise

    OpenAIRE

    Mueller, H. Gustav; Weber, Jennifer; Hornsby, Benjamin W.Y.

    2006-01-01

    Modern hearing aids commonly employ digital noise reduction (DNR) algorithms. The potential benefit of these algorithms is to provide improved speech understanding in noise or, at the least, to provide relaxed listening or increased ease of listening. In this study, 22 adults were fitted with 16-channel wide-dynamic-range compression hearing aids containing DNR processing. The DNR includes both modulation-based and Wiener-filter-type algorithms working simultaneously. Both speech intelligibil...

  2. The impact of musicianship on the cortical mechanisms related to separating speech from background noise.

    Science.gov (United States)

    Zendel, Benjamin Rich; Tremblay, Charles-David; Belleville, Sylvie; Peretz, Isabelle

    2015-05-01

    Musicians have enhanced auditory processing abilities. In some studies, these abilities are paralleled by an improved understanding of speech in noisy environments, partially due to more robust encoding of speech signals in noise at the level of the brainstem. Little is known about the impact of musicianship on attention-dependent cortical activity related to lexical access during a speech-in-noise task. To address this issue, we presented musicians and nonmusicians with single words mixed with three levels of background noise, across two conditions, while monitoring electrical brain activity. In the active condition, listeners repeated the words aloud, and in the passive condition, they ignored the words and watched a silent film. When background noise was most intense, musicians repeated more words correctly compared with nonmusicians. Auditory evoked responses were attenuated and delayed with the addition of background noise. In musicians, P1 amplitude was marginally enhanced during active listening and was related to task performance in the most difficult listening condition. By comparing ERPs from the active and passive conditions, we isolated an N400 related to lexical access. The amplitude of the N400 was not influenced by the level of background noise in musicians, whereas N400 amplitude increased with the level of background noise in nonmusicians. In nonmusicians, the increase in N400 amplitude was related to a reduction in task performance. In musicians only, there was a rightward shift of the sources contributing to the N400 as the level of background noise increased. This pattern of results supports the hypothesis that encoding of speech in noise is more robust in musicians and suggests that this facilitates lexical access. Moreover, the shift in sources suggests that musicians, to a greater extent than nonmusicians, may increasingly rely on acoustic cues to understand speech in noise. PMID:25390195

  3. Impact of Background Noise and Sentence Complexity on Processing Demands during Sentence Comprehension

    DEFF Research Database (Denmark)

    Wendt, Dorothea; Dau, Torsten; Hjortkjær, Jens

    2016-01-01

    two levels of background noise both corresponding to high intelligibility. A digit span and a reading span test were used to assess individual differences in the participants’ working memory capacity (WMC). The results showed that the subjectively rated effort was mostly affected by the noise level...

  4. Effects of Background Noise on Cortical Encoding of Speech in Autism Spectrum Disorders

    Science.gov (United States)

    Russo, Nicole; Zecker, Steven; Trommer, Barbara; Chen, Julia; Kraus, Nina

    2009-01-01

    This study provides new evidence of deficient auditory cortical processing of speech in noise in autism spectrum disorders (ASD). Speech-evoked responses (approximately 100-300 ms) in quiet and background noise were evaluated in typically-developing (TD) children and children with ASD. ASD responses showed delayed timing (both conditions) and…

  5. Quantum noise properties of CT images with anatomical textured backgrounds across reconstruction algorithms: FBP and SAFIRE

    Energy Technology Data Exchange (ETDEWEB)

    Solomon, Justin, E-mail: justin.solomon@duke.edu [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Samei, Ehsan [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 and Departments of Biomedical Engineering and Electrical and Computer Engineering, Pratt School of Engineering, Duke University, Durham, North Carolina 27705 (United States)

    2014-09-15

    Purpose: Quantum noise properties of CT images are generally assessed using simple geometric phantoms with uniform backgrounds. Such phantoms may be inadequate when assessing nonlinear reconstruction or postprocessing algorithms. The purpose of this study was to design anatomically informed textured phantoms and use the phantoms to assess quantum noise properties across two clinically available reconstruction algorithms, filtered back projection (FBP) and sinogram affirmed iterative reconstruction (SAFIRE). Methods: Two phantoms were designed to represent lung and soft-tissue textures. The lung phantom included intricate vessel-like structures along with embedded nodules (spherical, lobulated, and spiculated). The soft tissue phantom was designed based on a three-dimensional clustered lumpy background with included low-contrast lesions (spherical and anthropomorphic). The phantoms were built using rapid prototyping (3D printing) technology and, along with a uniform phantom of similar size, were imaged on a Siemens SOMATOM Definition Flash CT scanner and reconstructed with FBP and SAFIRE. Fifty repeated acquisitions were acquired for each background type and noise was assessed by estimating pixel-value statistics, such as standard deviation (i.e., noise magnitude), autocorrelation, and noise power spectrum. Noise stationarity was also assessed by examining the spatial distribution of noise magnitude. The noise properties were compared across background types and between the two reconstruction algorithms. Results: In FBP and SAFIRE images, noise was globally nonstationary for all phantoms. In FBP images of all phantoms, and in SAFIRE images of the uniform phantom, noise appeared to be locally stationary (within a reasonably small region of interest). Noise was locally nonstationary in SAFIRE images of the textured phantoms with edge pixels showing higher noise magnitude compared to pixels in more homogenous regions. For pixels in uniform regions, noise magnitude was

  6. Objective Measures of Listening Effort: Effects of Background Noise and Noise Reduction

    Science.gov (United States)

    Sarampalis, Anastasios; Kalluri, Sridhar; Edwards, Brent; Hafter, Ervin

    2009-01-01

    Purpose: This work is aimed at addressing a seeming contradiction related to the use of noise-reduction (NR) algorithms in hearing aids. The problem is that although some listeners claim a subjective improvement from NR, it has not been shown to improve speech intelligibility, often even making it worse. Method: To address this, the hypothesis…

  7. The Effects of Background Noise on Dichotic Listening to Consonant-Vowel Syllables

    Science.gov (United States)

    Sequeira, Sarah Dos Santos; Specht, Karsten; Hamalainen, Heikki; Hugdahl, Kenneth

    2008-01-01

    Lateralization of verbal processing is frequently studied with the dichotic listening technique, yielding a so called right ear advantage (REA) to consonant-vowel (CV) syllables. However, little is known about how background noise affects the REA. To address this issue, we presented CV-syllables either in silence or with traffic background noise…

  8. Adaptive cancellation of geomagnetic background noise for magnetic anomaly detection using coherence

    International Nuclear Information System (INIS)

    Magnetic anomaly detection (MAD) is an effective method for the detection of ferromagnetic targets against background magnetic fields. Currently, the performance of MAD systems is mainly limited by the background geomagnetic noise. Several techniques have been developed to detect target signatures, such as the synchronous reference subtraction (SRS) method. In this paper, we propose an adaptive coherent noise suppression (ACNS) method. The proposed method is capable of evaluating and detecting weak anomaly signals buried in background geomagnetic noise. Tests with real-world recorded magnetic signals show that the ACNS method can excellently remove the background geomagnetic noise by about 21 dB or more in high background geomagnetic field environments. Additionally, as a general form of the SRS method, the ACNS method offers appreciable advantages over the existing algorithms. Compared to the SRS method, the ACNS algorithm can eliminate the false target signals and represents a noise suppressing capability improvement of 6.4 dB. The positive outcomes in terms of intelligibility make this method a potential candidate for application in MAD systems. (paper)

  9. Measurement of speech levels in the presence of time varying background noise

    Science.gov (United States)

    Pearsons, K. S.; Horonjeff, R.

    1982-01-01

    Short-term speech level measurements which could be used to note changes in vocal effort in a time varying noise environment were studied. Knowing the changes in speech level would in turn allow prediction of intelligibility in the presence of aircraft flyover noise. Tests indicated that it is possible to use two second samples of speech to estimate long term root mean square speech levels. Other tests were also performed in which people read out loud during aircraft flyover noise. Results of these tests indicate that people do indeed raise their voice during flyovers at a rate of about 3-1/2 dB for each 10 dB increase in background level. This finding is in agreement with other tests of speech levels in the presence of steady state background noise.

  10. A reconstruction algorithm based on sparse representation for Raman signal processing under high background noise

    International Nuclear Information System (INIS)

    Background noise is one of the main interference sources of the Raman spectroscopy measurement and imaging technique. In this paper, a sparse representation based algorithm is presented to process the Raman signals under high background noise. In contrast with the existing de-noising methods, the proposed method reconstructs the pure Raman signals by estimating the Raman peak information. The advantage of the proposed algorithm is its high anti-noise capacity and low pure Raman signal reduction contributed by its reconstruction principle. Meanwhile, the Batch-OMP algorithm is applied to accelerate the training of the sparse representation. Therefore, it is very suitable to be adopted in the Raman measurement or imaging instruments to observe fast dynamic processes where the scanning time has to be shortened and the signal-to-noise ratio (SNR) of the raw tested signal is reduced. In the simulation and experiment, the de-noising result obtained by the proposed algorithm was better than the traditional Savitzky-Golay (S-G) filter and the fixed-threshold wavelet de-noising algorithm

  11. A reconstruction algorithm based on sparse representation for Raman signal processing under high background noise

    Science.gov (United States)

    Fan, X.; Wang, X.; Wang, X.; Xu, Y.; Que, J.; He, H.; Wang, X.; Tang, M.

    2016-02-01

    Background noise is one of the main interference sources of the Raman spectroscopy measurement and imaging technique. In this paper, a sparse representation based algorithm is presented to process the Raman signals under high background noise. In contrast with the existing de-noising methods, the proposed method reconstructs the pure Raman signals by estimating the Raman peak information. The advantage of the proposed algorithm is its high anti-noise capacity and low pure Raman signal reduction contributed by its reconstruction principle. Meanwhile, the Batch-OMP algorithm is applied to accelerate the training of the sparse representation. Therefore, it is very suitable to be adopted in the Raman measurement or imaging instruments to observe fast dynamic processes where the scanning time has to be shortened and the signal-to-noise ratio (SNR) of the raw tested signal is reduced. In the simulation and experiment, the de-noising result obtained by the proposed algorithm was better than the traditional Savitzky-Golay (S-G) filter and the fixed-threshold wavelet de-noising algorithm.

  12. Background noise cancellation of manatee vocalizations using an adaptive line enhancer.

    Science.gov (United States)

    Yan, Zheng; Niezrecki, Christopher; Cattafesta, Louis N; Beusse, Diedrich O

    2006-07-01

    The West Indian manatee (Trichechus manatus latirostris) has become an endangered species partly because of an increase in the number of collisions with boats. A device to alert boaters of the presence of manatees is desired. Previous research has shown that background noise limits the manatee vocalization detection range (which is critical for practical implementation). By improving the signal-to-noise ratio of the measured manatee vocalization signal, it is possible to extend the detection range. The finite impulse response (FIR) structure of the adaptive line enhancer (ALE) can detect and track narrow-band signals buried in broadband noise. In this paper, a constrained infinite impulse response (IIR) ALE, called a feedback ALE (FALE), is implemented to reduce the background noise. In addition, a bandpass filter is used as a baseline for comparison. A library consisting of 100 manatee calls spanning ten different signal categories is used to evaluate the performance of the bandpass filter, FIR-ALE, and FALE. The results show that the FALE is capable of reducing background noise by about 6.0 and 21.4 dB better than that of the FIR-ALE and bandpass filter, respectively, when the signal-to-noise ratio (SNR) of the original manatee call is -5 dB. PMID:16875212

  13. Humans, Fish, and Whales: How Right Whales Modify Calling Behavior in Response to Shifting Background Noise Conditions.

    Science.gov (United States)

    Parks, Susan E; Groch, Karina; Flores, Paulo; Sousa-Lima, Renata; Urazghildiiev, Ildar R

    2016-01-01

    This study investigates the role of behavioral plasticity in the variation of sound production of southern right whales (Eubalaena australis) in response to changes in the ambient background noise conditions. Data were collected from southern right whales in Brazilian waters in October and November 2011. The goal of this study was to quantify differences in right whale vocalizations recorded in low background noise as a control, fish chorus noise, and vessel noise. Variation in call parameters were detected among the three background noise conditions and have implications for future studies of noise effects on whale sound production. PMID:26611036

  14. Auditory-neurophysiological responses to speech during early childhood: Effects of background noise.

    Science.gov (United States)

    White-Schwoch, Travis; Davies, Evan C; Thompson, Elaine C; Woodruff Carr, Kali; Nicol, Trent; Bradlow, Ann R; Kraus, Nina

    2015-10-01

    Early childhood is a critical period of auditory learning, during which children are constantly mapping sounds to meaning. But this auditory learning rarely occurs in ideal listening conditions-children are forced to listen against a relentless din. This background noise degrades the neural coding of these critical sounds, in turn interfering with auditory learning. Despite the importance of robust and reliable auditory processing during early childhood, little is known about the neurophysiology underlying speech processing in children so young. To better understand the physiological constraints these adverse listening scenarios impose on speech sound coding during early childhood, auditory-neurophysiological responses were elicited to a consonant-vowel syllable in quiet and background noise in a cohort of typically-developing preschoolers (ages 3-5 yr). Overall, responses were degraded in noise: they were smaller, less stable across trials, slower, and there was poorer coding of spectral content and the temporal envelope. These effects were exacerbated in response to the consonant transition relative to the vowel, suggesting that the neural coding of spectrotemporally-dynamic speech features is more tenuous in noise than the coding of static features-even in children this young. Neural coding of speech temporal fine structure, however, was more resilient to the addition of background noise than coding of temporal envelope information. Taken together, these results demonstrate that noise places a neurophysiological constraint on speech processing during early childhood by causing a breakdown in neural processing of speech acoustics. These results may explain why some listeners have inordinate difficulties understanding speech in noise. Speech-elicited auditory-neurophysiological responses offer objective insight into listening skills during early childhood by reflecting the integrity of neural coding in quiet and noise; this paper documents typical response

  15. A particle velocity sensor to measure the sound from a structure in the presence of background noise

    NARCIS (Netherlands)

    Bree, de H.E.; Druyvesteyn, W.F.

    2005-01-01

    The performance (or quality) of a product is often checked by measuring the radiated sound (noise) from the vibrating structure. Often this test has to be done in an environment with background noise, which makes the measurement difficult. When using a (pressure) microphone the background noise can

  16. A Low-noise Germanium Ionization Spectrometer for Low-background Science

    CERN Document Server

    Aalseth, Craig E; Colaresi, Jim; Fast, James E; Hossbach, Todd W; Orrell, John L; Overman, Cory T; Scholz, Bjorn; VanDevender, Brent A; Yocum, K Michael

    2016-01-01

    Recent progress on the development of very low noise high purity germanium ionization spectrometers has produced an instrument of 1.2 kg mass and excellent noise performance. The detector was installed in a low-background cryostat intended for use in a direct detection search for low mass, WIMP dark matter. This Transaction reports the thermal characterization of the cryostat, specifications of the newly prepared 1.2 kg p-type point contact germanium detector, and the spectroscopic performance of the integrated system. The integrated detector and low background cryostat achieved full-width-at-half-maximum noise performance of 98 eV for an electronic pulse generator peak and 1.9 keV for the 1332 keV Co-60 gamma ray.

  17. Adaptive V/UV Speech Detection Based on Characterization of Background Noise

    Directory of Open Access Journals (Sweden)

    F. Beritelli

    2009-01-01

    Full Text Available The paper presents an adaptive system for Voiced/Unvoiced (V/UV speech detection in the presence of background noise. Genetic algorithms were used to select the features that offer the best V/UV detection according to the output of a background Noise Classifier (NC and a Signal-to-Noise Ratio Estimation (SNRE system. The system was implemented, and the tests performed using the TIMIT speech corpus and its phonetic classification. The results were compared with a nonadaptive classification system and the V/UV detectors adopted by two important speech coding standards: the V/UV detection system in the ETSI ES 202 212 v1.1.2 and the speech classification in the Selectable Mode Vocoder (SMV algorithm. In all cases the proposed adaptive V/UV classifier outperforms the traditional solutions giving an improvement of 25% in very noisy environments.

  18. Vibration transfers to measure the performance of vibration isolated platforms on site using background noise excitation

    NARCIS (Netherlands)

    Segerink, F.B.; Korterik, J.P.; Offerhaus, H.L.

    2011-01-01

    This article demonstrates a quick and easy way of quantifying the performance of a vibration-isolated platform. We measure the vibration transfer from floor to table using background noise excitation from the floor. As no excitation device is needed, our setup only requires two identical sensors (in

  19. Electromagnetic Compatibility (EMC) and Noise Background Testing for Double Chooz PMT System

    International Nuclear Information System (INIS)

    The Double Chooz PMT system is a HV/signal splitter. In this report is presented an electromagnetic compatibility and background noise testing for the Double Chooz PMT system. It was possible to proceed the EMC testing on different grounding configurations of PMT splitter due to its special PCB design, endowed of jumping points and a metal box ground electrode. (Author)

  20. Electromagnetic Compatibility (EMC) and Noise Background Testing for Double Chooz PMT System

    Energy Technology Data Exchange (ETDEWEB)

    Cepero, J. R.; Encabo Fernandez, F. J.; Pepe, I.; Verdugo, A.

    2009-05-21

    The Double Chooz PMT system is a HV/signal splitter. In this report is presented an electromagnetic compatibility and background noise testing for the Double Chooz PMT system. It was possible to proceed the EMC testing on different grounding configurations of PMT splitter due to its special PCB design, endowed of jumping points and a metal box ground electrode. (Author)

  1. Nonparametric VSS-APA based on precise background noise power estimate

    Institute of Scientific and Technical Information of China (English)

    昊翔; 赖晓翰; 陈隆道; 蔡忠法

    2015-01-01

    The adaptive algorithm used for echo cancellation (EC) system needs to provide 1) low misadjustment and 2) high convergence rate. The affine projection algorithm (APA) is a better alternative than normalized least mean square (NLMS) algorithm in EC applications where the input signal is highly correlated. Since the APA with a constant step-size has to make compromise between the performance criteria 1) and 2), a variable step-size APA (VSS-APA) provides a more reliable solution. A nonparametric VSS-APA (NPVSS-APA) is proposed by recovering the background noise within the error signal instead of cancelling the a posteriori errors. The most problematic term of its variable step-size formula is the value of background noise power (BNP). The power difference between the desired signal and output signal, which equals the power of error signal statistically, has been considered the BNP estimate in a rough manner. Considering that the error signal consists of background noise and misalignment noise, a precise BNP estimate is achieved by multiplying the rough estimate with a corrective factor. After the analysis on the power ratio of misalignment noise to background noise of APA, the corrective factor is formulated depending on the projection order and the latest value of variable step-size. The new algorithm which does not require any a priori knowledge of EC environment has the advantage of easier controllability in practical application. The simulation results in the EC context indicate the accuracy of the proposed BNP estimate and the more effective behavior of the proposed algorithm compared with other versions of APA class.

  2. Speech-in-noise perception deficit in adults with dyslexia: effects of background type and listening configuration.

    OpenAIRE

    Dole, Marjorie; Hoen, Michel; Meunier, Fanny

    2012-01-01

    Developmental dyslexia is associated with impaired speech-in-noise perception. The goal of the present research was to further characterize this deficit in dyslexic adults. In order to specify the mechanisms and processing strategies used by adults with dyslexia during speech-in-noise perception, we explored the influence of background type, presenting single target-words against backgrounds made of cocktail party sounds, modulated speech-derived noise or stationary noise. We also evaluated t...

  3. Analysis of Background Seismic Noise Recorded at the Amundsen-Scott South Pole Station, Antarctica

    Science.gov (United States)

    Anderson, K. R.; Aster, R.; Beaudoin, B. C.; Butler, R.

    2006-12-01

    station. Therefore, encroachment of any of these noise sources into the Quiet Sector will adversely affect the signal-to-noise ratio in the frequencies above 1 Hz for seismograms recorded at QSPA. At this point, QSPA is by far the quietest seismic station in the world at these high frequencies. We hope that we can preserve these low background noise levels and keep the QSPA one of the quietest places on Earth.

  4. Estimation of background noise level on seismic station using statistical analysis for improved analysis accuracy

    Science.gov (United States)

    Han, S. M.; Hahm, I.

    2015-12-01

    We evaluated the background noise level of seismic stations in order to collect the observation data of high quality and produce accurate seismic information. Determining of the background noise level was used PSD (Power Spectral Density) method by McNamara and Buland (2004) in this study. This method that used long-term data is influenced by not only innate electronic noise of sensor and a pulse wave resulting from stabilizing but also missing data and controlled by the specified frequency which is affected by the irregular signals without site characteristics. It is hard and inefficient to implement process that filters out the abnormal signal within the automated system. To solve these problems, we devised a method for extracting the data which normally distributed with 90 to 99% confidence intervals at each period. The availability of the method was verified using 62-seismic stations with broadband and short-period sensors operated by the KMA (Korea Meteorological Administration). Evaluation standards were NHNM (New High Noise Model) and NLNM (New Low Noise Model) published by the USGS (United States Geological Survey). It was designed based on the western United States. However, Korean Peninsula surrounded by the ocean on three sides has a complicated geological structure and a high population density. So, we re-designed an appropriate model in Korean peninsula by statistically combined result. The important feature is that secondary-microseism peak appeared at a higher frequency band. Acknowledgements: This research was carried out as a part of "Research for the Meteorological and Earthquake Observation Technology and Its Application" supported by the 2015 National Institute of Meteorological Research (NIMR) in the Korea Meteorological Administration.

  5. Anatomical background noise power spectrum in differential phase contrast breast images

    Science.gov (United States)

    Garrett, John; Ge, Yongshuai; Li, Ke; Chen, Guang-Hong

    2015-03-01

    In x-ray breast imaging, the anatomical noise background of the breast has a significant impact on the detection of lesions and other features of interest. This anatomical noise is typically characterized by a parameter, β, which describes a power law dependence of anatomical noise on spatial frequency (the shape of the anatomical noise power spectrum). Large values of β have been shown to reduce human detection performance, and in conventional mammography typical values of β are around 3.2. Recently, x-ray differential phase contrast (DPC) and the associated dark field imaging methods have received considerable attention as possible supplements to absorption imaging for breast cancer diagnosis. However, the impact of these additional contrast mechanisms on lesion detection is not yet well understood. In order to better understand the utility of these new methods, we measured the β indices for absorption, DPC, and dark field images in 15 cadaver breast specimens using a benchtop DPC imaging system. We found that the measured β value for absorption was consistent with the literature for mammographic acquisitions (β = 3.61±0.49), but that both DPC and dark field images had much lower values of β (β = 2.54±0.75 for DPC and β = 1.44±0.49 for dark field). In addition, visual inspection showed greatly reduced anatomical background in both DPC and dark field images. These promising results suggest that DPC and dark field imaging may help provide improved lesion detection in breast imaging, particularly for those patients with dense breasts, in whom anatomical noise is a major limiting factor in identifying malignancies.

  6. Impact of Background Noise and Sentence Complexity on Processing Demands during Sentence Comprehension

    Science.gov (United States)

    Wendt, Dorothea; Dau, Torsten; Hjortkjær, Jens

    2016-01-01

    Speech comprehension in adverse listening conditions can be effortful even when speech is fully intelligible. Acoustical distortions typically make speech comprehension more effortful, but effort also depends on linguistic aspects of the speech signal, such as its syntactic complexity. In the present study, pupil dilations, and subjective effort ratings were recorded in 20 normal-hearing participants while performing a sentence comprehension task. The sentences were either syntactically simple (subject-first sentence structure) or complex (object-first sentence structure) and were presented in two levels of background noise both corresponding to high intelligibility. A digit span and a reading span test were used to assess individual differences in the participants’ working memory capacity (WMC). The results showed that the subjectively rated effort was mostly affected by the noise level and less by syntactic complexity. Conversely, pupil dilations increased with syntactic complexity but only showed a small effect of the noise level. Participants with higher WMC showed increased pupil responses in the higher-level noise condition but rated sentence comprehension as being less effortful compared to participants with lower WMC. Overall, the results demonstrate that pupil dilations and subjectively rated effort represent different aspects of effort. Furthermore, the results indicate that effort can vary in situations with high speech intelligibility. PMID:27014152

  7. Background noise levels and correlation with ship traffic in the Gulf of Catania

    Science.gov (United States)

    Viola, Salvatore; Buscaino, Giuseppa; Caruso, Francesco; Chierici, Francesco; Embriaco, Davide; Favali, Paolo; Giovanetti, Gabriele; Grammauta, Roasario; Larosa, Giuseppina; Pavan, Gianni; Pellegrino, Carmelo; Pulvirenti, Sara; Riccobene, Giorgio; Sciacca, Virginia; Simeone, Francesco; Beranzoli, Laura; Marinaro, Giuditta

    2015-04-01

    In the last decades the growing interest in the evaluation of the underwater acoustic noise for studies in the fields of geology, biology and high-energy physics is driving the scientific community to collaborate towards a multidisciplinary approach to the topic. In June 2012 in the framework of the European project EMSO, a multidisciplinary underwater observatory, named NEMO-SN1, was installed 25 km off-shore the port of Catania, at a depth of 2100 m and operated until May 2013 by INFN (Istituto Nazionale di Fisica Nucleare) and INGV (Istituto Nazionale di Geofisica e Vulcanologia). NEMO-SN1 hosted aboard geophysical, oceanographic and acoustic sensors: among these a seismic hydrophone model SMID DT-405D(V). In this work, conducted within the activity of the SMO project, the results on the evaluation of the underwater acoustic pollution in the Gulf of Catania through SMID DT-405D(V) recordings are presented. The seismic hydrophone provided a data set of about 11 months of continuous (24/7) recordings. Underwater sounds have been continuously digitized at a sampling frequency of 2 kHz and the acquired data have been stored in 10min long files for off-line analysis. To describe one-year background noise levels, the mean integrated acoustic noise was measured every second (sampling frequency 2000, NFFT 2048) in the 1/3 octave bands with centre frequency 63 Hz and for each 10 minutes-long file the 5th, the 50th and the 98th percentiles were calculated. Measured noise was correlated with the shipping traffic in the area, thanks to the data provided by an AIS receiver installed at the INFN-Laboratori Nazionali del Sud. An acoustic noise increment was measured in coincidence with the passing of crafts in the area and it was possible to identify the characteristic spectrum of each ship. A simple model for the estimation of the acoustic noise induced by the ships passing through the area was developed. The model was applied by using AIS data acquired during the operation

  8. Bayesian Noise Estimation for Non-ideal Cosmic Microwave Background Experiments

    Science.gov (United States)

    Wehus, I. K.; Næss, S. K.; Eriksen, H. K.

    2012-03-01

    We describe a Bayesian framework for estimating the time-domain noise covariance of cosmic microwave background (CMB) observations, typically parameterized in terms of a 1/f frequency profile. This framework is based on the Gibbs sampling algorithm, which allows for exact marginalization over nuisance parameters through conditional probability distributions. In this paper, we implement support for gaps in the data streams and marginalization over fixed time-domain templates, and also outline how to marginalize over confusion from CMB fluctuations, which may be important for high signal-to-noise experiments. As a by-product of the method, we obtain proper constrained realizations, which themselves can be useful for map making. To validate the algorithm, we demonstrate that the reconstructed noise parameters and corresponding uncertainties are unbiased using simulated data. The CPU time required to process a single data stream of 100,000 samples with 1000 samples removed by gaps is 3 s if only the maximum posterior parameters are required, and 21 s if one also wants to obtain the corresponding uncertainties by Gibbs sampling.

  9. BAYESIAN NOISE ESTIMATION FOR NON-IDEAL COSMIC MICROWAVE BACKGROUND EXPERIMENTS

    International Nuclear Information System (INIS)

    We describe a Bayesian framework for estimating the time-domain noise covariance of cosmic microwave background (CMB) observations, typically parameterized in terms of a 1/f frequency profile. This framework is based on the Gibbs sampling algorithm, which allows for exact marginalization over nuisance parameters through conditional probability distributions. In this paper, we implement support for gaps in the data streams and marginalization over fixed time-domain templates, and also outline how to marginalize over confusion from CMB fluctuations, which may be important for high signal-to-noise experiments. As a by-product of the method, we obtain proper constrained realizations, which themselves can be useful for map making. To validate the algorithm, we demonstrate that the reconstructed noise parameters and corresponding uncertainties are unbiased using simulated data. The CPU time required to process a single data stream of 100,000 samples with 1000 samples removed by gaps is 3 s if only the maximum posterior parameters are required, and 21 s if one also wants to obtain the corresponding uncertainties by Gibbs sampling.

  10. Dependence of regular background noise of VLF radiation and thunder-storm activity on solar wind proton density

    International Nuclear Information System (INIS)

    Correlation of the intensity of slowly changing regular background noise within 9.7 kHz frequency in Yakutsk (L = 3) and of the solar wind density protons was determined. This result explains the reverse dependence of the intensity of the regular background noise on the solar activity, 27-day frequency, increase before and following geomagnetic storms, absence of relation with Kp index of geomagnetic activity. Conclusion is made that growth of density of the solar wind protons results in increase of the regular background noise and thunderstorm activity

  11. Study of the neutron background noise generated by muons in the Edelweiss-2 experiment

    International Nuclear Information System (INIS)

    This thesis contributes to the Edelweiss experiment whose aim is to detect interactions between neutralinos and target nuclei. Bolometers used in Edelweiss combine the detection of phonons with the detection of electric charges generated by the energy deposition. This double detection enables us to discard background signals due to electronic interactions and soon detection sensitivity of the experiment will be limited by the neutron background noise due to residual cosmic muons. This work is dedicated to a detailed study of muon inelastic interactions and the consequent production of neutrons. Simulations show that the expected neutron flux is so high that the direct detection of muons is required in order to link it to the neutron signal issued by the bolometer. Results from simulations show that plastic scintillators might be the main components of the muon detector

  12. Speech-in-Noise Perception Deficit in Adults with Dyslexia: Effects of Background Type and Listening Configuration

    Science.gov (United States)

    Dole, Marjorie; Hoen, Michel; Meunier, Fanny

    2012-01-01

    Developmental dyslexia is associated with impaired speech-in-noise perception. The goal of the present research was to further characterize this deficit in dyslexic adults. In order to specify the mechanisms and processing strategies used by adults with dyslexia during speech-in-noise perception, we explored the influence of background type,…

  13. Effects of signal features and background noise on distance cue discrimination by a songbird.

    Science.gov (United States)

    Pohl, Nina U; Klump, Georg M; Langemann, Ulrike

    2015-04-01

    During the transmission of acoustic signals, the spectral and temporal properties of the original signal are degraded, and with increasing distance more and more echo patterns are imposed. It is well known that these physical alterations provide useful cues to assess the distance of a sound source. Previous studies in birds have shown that birds employ the degree of degradation of a signal to estimate the distance of another singing male (referred to as ranging). Little is known about how acoustic masking by background noise interferes with ranging, and if the number of song elements and stimulus familiarity affect the ability to discriminate between degraded and undegraded signals. In this study we trained great tits (Parus major L.) to discriminate between signal variants in two background types, a silent condition and a condition consisting of a natural dawn chorus. We manipulated great tit song types to simulate patterns of reverberation and degradation equivalent to transmission distances of between 5 and 160 m. The birds' responses were significantly affected by the differences between the signal variants and by background type. In contrast, stimulus familiarity or their element number had no significant effect on signal discrimination. Although background type was a significant main effect with respect to the response latencies, the great tits' overall performance in the noisy dawn chorus was similar to the performance in silence. PMID:25657204

  14. The role of narrowband filtering in improving signal-to-noise ratio of ghost imaging with thermal light background

    CERN Document Server

    Yang, Dongyue; Wu, Guohua; Luo, Bin; Yin, Longfei; Guo, Hong

    2016-01-01

    In ghost imaging with narrow-band signal in thermal light background, signal arm filters bring higher value and upper limit of signal-to-noise ratio (SNR), and faster speed to reach that limit. The narrower bandwidth, the better.

  15. Monte-Carlo simulation of noise in hard X-ray Transmission Crystal Spectrometers: identification of contributors to the background noise and shielding optimization.

    Science.gov (United States)

    Thfoin, I; Reverdin, C; Hulin, S; Szabo, C I; Bastiani-Ceccotti, S; Batani, D; Brambrink, E; Koenig, M; Duval, A; Leboeuf, X; Lecherbourg, L; Rossé, B; Morace, A; Santos, J J; Vaisseau, X; Fourment, C; Giuffrida, L; Nakatsutsumi, M

    2014-11-01

    Transmission crystal spectrometers (TCS) are used on many laser facilities to record hard X-ray spectra. During experiments, signal recorded on imaging plates is often degraded by a background noise. Monte-Carlo simulations made with the code GEANT4 show that this background noise is mainly generated by diffusion of MeV electrons and very hard X-rays. An experiment, carried out at LULI2000, confirmed that the use of magnets in front of the diagnostic, that bent the electron trajectories, reduces significantly this background. The new spectrometer SPECTIX (Spectromètre PETAL à Cristal en TransmIssion X), built for the LMJ/PETAL facility, will include this optimized shielding. PMID:25430191

  16. Monte-Carlo simulation of noise in hard X-ray Transmission Crystal Spectrometers: Identification of contributors to the background noise and shielding optimization

    Energy Technology Data Exchange (ETDEWEB)

    Thfoin, I., E-mail: isabelle.lantuejoul@cea.fr; Reverdin, C.; Duval, A.; Leboeuf, X.; Lecherbourg, L.; Rossé, B. [CEA, Centre de Saclay, IRFU, F-91191 Gif-sur-Yvette (France); Hulin, S.; Batani, D.; Santos, J. J.; Vaisseau, X.; Fourment, C.; Giuffrida, L. [CELIA, Université de Bordeaux-CNRS-CEA, F-33405 Talence (France); Szabo, C. I. [Laboratoire Kastler Brossel, ENS, CNRS, UPMC, 75005 Paris Cedex (France); Bastiani-Ceccotti, S.; Brambrink, E.; Koenig, M.; Nakatsutsumi, M. [LULI Ecole Polytechnique, CNRS, CEA, UPMC, 91128 Palaiseau (France); Morace, A. [University of Milano, via Celoria 16, 20133 Milano (Italy)

    2014-11-15

    Transmission crystal spectrometers (TCS) are used on many laser facilities to record hard X-ray spectra. During experiments, signal recorded on imaging plates is often degraded by a background noise. Monte-Carlo simulations made with the code GEANT4 show that this background noise is mainly generated by diffusion of MeV electrons and very hard X-rays. An experiment, carried out at LULI2000, confirmed that the use of magnets in front of the diagnostic, that bent the electron trajectories, reduces significantly this background. The new spectrometer SPECTIX (Spectromètre PETAL à Cristal en TransmIssion X), built for the LMJ/PETAL facility, will include this optimized shielding.

  17. Precision of least-squares mono-exponential decay time estimates from optical measurements with both photon shot noise and background noise

    International Nuclear Information System (INIS)

    Equations are derived for the precision of least-squares estimates of mono-exponential decay times from optical measurements containing both photon shot noise and background noise. The special case of data containing only photon shot noise leads to the same equation as that derived previously by others using the maximum likelihood estimation method. It is shown that for a sufficiently large number of data points used in the fit, spanning up to approximately ten decay times, the lifetime estimate precision reaches a limit value being the inverse square root of the number of photons contained in the decay curve used for the estimate. Further, an extension to the general case where both types of noise are present is provided. Approximating photon statistical noise as normally distributed, the expressions for precision are shown to be valid even for very low signal-to-noise ratios. Thus, the theory provides a straightforward and useful tool to assess the lifetime estimate precision from a single decay measurement. (paper)

  18. Increasing session-to-session transfer in a brain-computer interface with on-site background noise acquisition

    Science.gov (United States)

    Cho, Hohyun; Ahn, Minkyu; Kim, Kiwoong; Jun, Sung Chan

    2015-12-01

    Objective. A brain-computer interface (BCI) usually requires a time-consuming training phase during which data are collected and used to generate a classifier. Because brain signals vary dynamically over time (and even over sessions), this training phase may be necessary each time the BCI system is used, which is impractical. However, the variability in background noise, which is less dependent on a control signal, may dominate the dynamics of brain signals. Therefore, we hypothesized that an understanding of variations in background noise may allow existing data to be reused by incorporating the noise characteristics into the feature extraction framework; in this way, new session data are not required each time and this increases the feasibility of the BCI systems. Approach. In this work, we collected background noise during a single, brief on-site acquisition session (approximately 3 min) immediately before a new session, and we found that variations in background noise were predictable to some extent. Then we implemented this simple session-to-session transfer strategy with a regularized spatiotemporal filter (RSTF), and we tested it with a total of 20 cross-session datasets collected over multiple days from 12 subjects. We also proposed and tested a bias correction (BC) in the RSTF. Main results. We found that our proposed session-to-session strategies yielded a slightly less or comparable performance to the conventional paradigm (each session training phase is needed with an on-site training dataset). Furthermore, using an RSTF only and an RSTF with a BC outperformed existing approaches in session-to-session transfers. Significance. We inferred from our results that, with an on-site background noise suppression feature extractor and pre-existing training data, further training time may be unnecessary.

  19. An investigation of cognitive test performance across conditions of silence, background noise and music as a function of neuroticism.

    OpenAIRE

    Reynolds, J; McClelland, A; A. Furnham

    2013-01-01

    The present study investigates the role of trait neuroticism on cognitive performance under distraction. Seventy participants were given a personality test and then undertook a number of different cognitive tasks in silence, in the presence of popular music and in background noise. It was predicted that performance on a general intelligence test, a test of abstract reasoning, and a mental arithmetic task would be adversely affected by background sounds. It was predicted that neuroticism would...

  20. Effects of background noise on transiently evoked otoacoustic emissions in newborn hearing screening

    Directory of Open Access Journals (Sweden)

    Chandrakant Vishwakarma

    2015-01-01

    Full Text Available Introduction: Newborn hearing screening program is one of the services offered in Neonatal Intensive Care Units (NICU by most of the neonatologist today. Aim of the Study: Present study aimed to investigate the ambient noise levels which allow successful transient evoked otoacoustic emission testing. Method: 25 normal hearing neonates (group 1 and 25 normal hearing adults (group 2 participated in the study. Both groups were tested at 30 dB sound pressure level (SPL, 40 dB SPL and 50 dB SPL noise levels. Results and Discussion: Tests results showed with increase in noise levels number of passing subjects decreased and also testing was done at times more than once. Conclusion: Tester should take care of noise levels while doing the test in NICU, which can give false negative responses.

  1. Spectral subtraction-based speech enhancement for cochlear implant patients in background noise

    Science.gov (United States)

    Yang, Li-Ping; Fu, Qian-Jie

    2005-03-01

    A single-channel speech enhancement algorithm utilizing speech pause detection and nonlinear spectral subtraction is proposed for cochlear implant patients in the present study. The spectral subtraction algorithm estimates the short-time spectral magnitude of speech by subtracting the estimated noise spectral magnitude from the noisy speech spectral magnitude. The artifacts produced by spectral subtraction (such as ``musical noise'') were significantly reduced by combining variance-reduced gain function and spectral flooring. Sentence recognition by seven cochlear implant subjects was tested under different noisy listening conditions (speech-shaped noise and 6-talker speech babble at +9, +6, +3, and 0 dB SNR) with and without the speech enhancement algorithm. For speech-shaped noise, performance for all subjects at all SNRs was significantly improved by the speech enhancement algorithm; for speech babble, performance was only modestly improved. The results suggest that the proposed speech enhancement algorithm may be beneficial for implant users in noisy listening. .

  2. An investigation of cognitive test performance across conditions of silence, background noise and music as a function of neuroticism.

    Science.gov (United States)

    Reynolds, James; McClelland, Alastair; Furnham, Adrian

    2014-01-01

    The present study investigates the role of trait neuroticism on cognitive performance under distraction. Seventy participants were given a personality test and then undertook a number of different cognitive tasks in silence, in the presence of popular music and in background noise. It was predicted that performance on a general intelligence test, a test of abstract reasoning, and a mental arithmetic task would be adversely affected by background sounds. It was predicted that neuroticism would be negatively correlated with performance on the mental arithmetic task but only when the individuals were working in the presence of background sound. Stable vs. unstable participant's performance on a mental arithmetic task during noise was significantly higher as predicted. The results provided partial support for the hypotheses and are discussed with respect to previous findings in the literature on personality (particularly introversion-extraversion) and distraction on cognitive task performance. Limitations are noted. PMID:24215564

  3. Effect of scanner acoustic background noise on strict resting-state fMRI

    Directory of Open Access Journals (Sweden)

    C. Rondinoni

    2013-04-01

    Full Text Available Functional MRI (fMRI resting-state experiments are aimed at identifying brain networks that support basal brain function. Although most investigators consider a ‘resting-state' fMRI experiment with no specific external stimulation, subjects are unavoidably under heavy acoustic noise produced by the equipment. In the present study, we evaluated the influence of auditory input on the resting-state networks (RSNs. Twenty-two healthy subjects were scanned using two similar echo-planar imaging sequences in the same 3T MRI scanner: a default pulse sequence and a reduced “silent” pulse sequence. Experimental sessions consisted of two consecutive 7-min runs with noise conditions (default or silent counterbalanced across subjects. A self-organizing group independent component analysis was applied to fMRI data in order to recognize the RSNs. The insula, left middle frontal gyrus and right precentral and left inferior parietal lobules showed significant differences in the voxel-wise comparison between RSNs depending on noise condition. In the presence of low-level noise, these areas Granger-cause oscillations in RSNs with cognitive implications (dorsal attention and entorhinal, while during high noise acquisition, these connectivities are reduced or inverted. Applying low noise MR acquisitions in research may allow the detection of subtle differences of the RSNs, with implications in experimental planning for resting-state studies, data analysis, and ergonomic factors.

  4. Effect of scanner acoustic background noise on strict resting-state fMRI

    Directory of Open Access Journals (Sweden)

    C. Rondinoni

    2013-12-01

    Full Text Available Functional MRI (fMRI resting-state experiments are aimed at identifying brain networks that support basal brain function. Although most investigators consider a ‘resting-state' fMRI experiment with no specific external stimulation, subjects are unavoidably under heavy acoustic noise produced by the equipment. In the present study, we evaluated the influence of auditory input on the resting-state networks (RSNs. Twenty-two healthy subjects were scanned using two similar echo-planar imaging sequences in the same 3T MRI scanner: a default pulse sequence and a reduced “silent” pulse sequence. Experimental sessions consisted of two consecutive 7-min runs with noise conditions (default or silent counterbalanced across subjects. A self-organizing group independent component analysis was applied to fMRI data in order to recognize the RSNs. The insula, left middle frontal gyrus and right precentral and left inferior parietal lobules showed significant differences in the voxel-wise comparison between RSNs depending on noise condition. In the presence of low-level noise, these areas Granger-cause oscillations in RSNs with cognitive implications (dorsal attention and entorhinal, while during high noise acquisition, these connectivities are reduced or inverted. Applying low noise MR acquisitions in research may allow the detection of subtle differences of the RSNs, with implications in experimental planning for resting-state studies, data analysis, and ergonomic factors.

  5. Precision of mono-exponential decay estimates from rapid lifetime determination in the presence of signal photon and background noise

    International Nuclear Information System (INIS)

    Precision of mono-exponential decay time estimates using the rapid lifetime determination (RLD) method is analyzed, taking into account both signal photon shot noise and Gaussian background noise. Analytical expressions are derived that enable selection of optimum gate width and inter-gate delay values, and the range of validity of these expressions is tested with random number simulations. The analysis includes both the general case when gates are allowed to overlap in time and the specific case when they do not overlap. The analysis is also applicable to whole decay measurements, from which two gates are selected afterwards for lifetime estimation. (paper)

  6. Impacts of Reverberation Time, Absorption Location and Background Noise on Listening Conditions in Multi Source Environment

    DEFF Research Database (Denmark)

    Saher, Konca; Rindel, Jens Holger; Nijs, Lau; van der Voorden, Marinus

    2005-01-01

    This paper is part of a PhD research project focusing on the prediction of the acoustical quality in living rooms and workspaces in institutions for mentally challenged people. One of the important activities in these rooms is simultaneous conversations. In this respect, the speech intelligibility...... environment are done according to different reverberation and absorption (with and without a screen) conditions. Then listening tests with the subjects are accomplished. The results indicate that the judgment of reverberation; loudness and type of noise source and its impact on speech intelligibility......, listening effort and noise distraction, are a central issue. Lower RT values help for better speech intelligibility and introduction of a screen is an effective element for obtaining a lower noise level. However, the interaction between objective and subjective parameters shows some variance. The type and...

  7. Development and Certification of Ultrasonic Background Noise Test (UBNT) System for use on the International Space Station (ISS)

    Science.gov (United States)

    Prosser, William H.; Madaras, Eric I.

    2011-01-01

    As a next step in the development and implementation of an on-board leak detection and localization system on the International Space Station (ISS), there is a documented need to obtain measurements of the ultrasonic background noise levels that exist within the ISS. This need is documented in the ISS Integrated Risk Management System (IRMA), Watch Item #4669. To address this, scientists and engineers from the Langley Research Center (LaRC) and the Johnson Space Center (JSC), proposed to the NASA Engineering and Safety Center (NESC) and the ISS Vehicle Office a joint assessment to develop a flight package as a Station Development Test Objective (SDTO) that would perform ultrasonic background noise measurements within the United States (US) controlled ISS structure. This document contains the results of the assessment

  8. Detection of WIMPs in the Edelweiss experiment. Study of the radioactive background noise and measurements with bolometers

    International Nuclear Information System (INIS)

    This thesis is dedicated to the detection of black matter in the form of WIMPs (weakly interacting massive particle). The characteristics of the interaction of WIMPs with matter are recalled. The very low number of expected events (<1 event/day.Kg) implies a radioactive background noise as weak as possible, furthermore the exponential decrease of the interacting rate with increasing energy calls for detectors with very low thresholds. Bolometers present advantages in WIMPs detection: i) very good resolution and very low thresholds, ii) very broad range of materials that can be used as absorber, the only requirements are: a crystal structure, to be a diamagnetic isolator and to have a convenient Debye temperature, iii) the possibility of detecting ionizing or non-ionizing particles, iv) the possibility of identifying the incident particle by measuring both temperature and another parameter such as ionization or scintillation, and v) the possibility of localizing the interaction inside the absorber by detecting ballistic phonons. The problematic of radioactive background noise is presented and the answers to the different sources (cosmic radiation,natural and artificial radioactivity) generating the background noise are examined. The materials used in the building of the detector and cryostat must be carefully chosen, they should be as little radioactive as possible. The test benches used to select materials for the Edelweiss experiment are described. The first measurements concerning the detectors Ge-4 and Ge-7 are presented. (A.C.)

  9. 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 ...

  10. Memory performance on the Auditory Inference Span Test is independent of background noise type for young adults with normal hearing at high speech intelligibility.

    Science.gov (United States)

    Rönnberg, Niklas; Rudner, Mary; Lunner, Thomas; Stenfelt, Stefan

    2014-01-01

    Listening in noise is often perceived to be effortful. This is partly because cognitive resources are engaged in separating the target signal from background noise, leaving fewer resources for storage and processing of the content of the message in working memory. The Auditory Inference Span Test (AIST) is designed to assess listening effort by measuring the ability to maintain and process heard information. The aim of this study was to use AIST to investigate the effect of background noise types and signal-to-noise ratio (SNR) on listening effort, as a function of working memory capacity (WMC) and updating ability (UA). The AIST was administered in three types of background noise: steady-state speech-shaped noise, amplitude modulated speech-shaped noise, and unintelligible speech. Three SNRs targeting 90% speech intelligibility or better were used in each of the three noise types, giving nine different conditions. The reading span test assessed WMC, while UA was assessed with the letter memory test. Twenty young adults with normal hearing participated in the study. Results showed that AIST performance was not influenced by noise type at the same intelligibility level, but became worse with worse SNR when background noise was speech-like. Performance on AIST also decreased with increasing memory load level. Correlations between AIST performance and the cognitive measurements suggested that WMC is of more importance for listening when SNRs are worse, while UA is of more importance for listening in easier SNRs. The results indicated that in young adults with normal hearing, the effort involved in listening in noise at high intelligibility levels is independent of the noise type. However, when noise is speech-like and intelligibility decreases, listening effort increases, probably due to extra demands on cognitive resources added by the informational masking created by the speech fragments and vocal sounds in the background noise. PMID:25566159

  11. A MARKOV CHAIN MONTE CARLO ALGORITHM FOR ANALYSIS OF LOW SIGNAL-TO-NOISE COSMIC MICROWAVE BACKGROUND DATA

    International Nuclear Information System (INIS)

    We present a new Markov Chain Monte Carlo (MCMC) algorithm for cosmic microwave background (CMB) analysis in the low signal-to-noise regime. This method builds on and complements the previously described CMB Gibbs sampler, and effectively solves the low signal-to-noise inefficiency problem of the direct Gibbs sampler. The new algorithm is a simple Metropolis-Hastings sampler with a general proposal rule for the power spectrum, C l, followed by a particular deterministic rescaling operation of the sky signal, s. The acceptance probability for this joint move depends on the sky map only through the difference of χ2 between the original and proposed sky sample, which is close to unity in the low signal-to-noise regime. The algorithm is completed by alternating this move with a standard Gibbs move. Together, these two proposals constitute a computationally efficient algorithm for mapping out the full joint CMB posterior, both in the high and low signal-to-noise regimes.

  12. Experimental study of neutron induced background noise on gated x-ray framing cameras

    International Nuclear Information System (INIS)

    A temporally gated x-ray framing camera based on a proximity focus microchannel plate is one of the most important diagnostic tools of inertial confinement fusion experiments. However, fusion neutrons produced in imploded capsules interact with structures surrounding the camera and produce background to x-ray signals. To understand the mechanisms of this neutron induced background, we tested several gated x-ray cameras in the presence of 14 MeV neutrons produced at the Omega laser facility. Differences between background levels observed with photographic film readout and charge-coupled-device readout have been studied.

  13. Long-term measurements of acoustic background noise in very deep sea

    Energy Technology Data Exchange (ETDEWEB)

    Riccobene, G. [Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare, Via S. Sofia 62, 95123 Catania (Italy)], E-mail: riccobene@lns.infn.it

    2009-06-01

    The NEMO (NEutrino Mediterranean Observatory) Collaboration installed, 25 km E offshore the port of Catania (Sicily) at 2000 m depth, an underwater laboratory to perform long-term tests of prototypes and new technologies for an underwater high energy neutrino km{sup 3}-scale detector in the Mediterranean Sea. In this framework the Collaboration deployed and successfully operated for about two years, starting from January 2005, an experimental apparatus for on-line monitoring of deep-sea noise. The station was equipped with four hydrophones and it is operational in the range 30 Hz-43 kHz. This interval of frequencies matches the range suitable for the proposed acoustic detection technique of high energy neutrinos. Hydrophone signals were digitized underwater at 96 kHz sampling frequency and 24 bits resolution. The stored data library, consisting of more than 2000 h of recordings, is a unique tool to model underwater acoustic noise at large depth, to characterize its variations as a function of environmental parameters, biological sources and human activities (ship traffic, etc.), and to determine the presence of cetaceans in the area.

  14. Effect of Background Noise on the Photon Statistics of Triggered Single Molecules

    Institute of Scientific and Technical Information of China (English)

    XIAO Lian-Tuan; ZHAO Yan-Ting; HUANG Tao; ZHAO Jian-Ming; YIN Wang-Bao; JIA Suo-Tang

    2004-01-01

    @@ We theoretically derive exact expressions for Mandel's Q parameter of the triggered single molecular source, which is inferred from the probabilities PRS(n) using the recorded of each photon detection event based on Hanbury Brown and Twiss detection. The real triggered source is recognized as an ideal single photon source with a Poissonian statistics background. How to decease the background and to increase the efficiency are discussed. It is established that the sub-Poissonian statistics formation can be determined by comparing the measured QRS of the real single triggered molecular with QC of the Poissonian source containing the same mean photons. By this method, we also give an efficient way to measure signal-to-background ratios of triggered single photons.

  15. Background Noise Analysis in a Few-Photon-Level Qubit Memory

    Science.gov (United States)

    Mittiga, Thomas; Kupchak, Connor; Jordaan, Bertus; Namazi, Mehdi; Nolleke, Christian; Figeroa, Eden

    2014-05-01

    We have developed an Electromagnetically Induced Transparency based polarization qubit memory. The device is composed of a dual-rail probe field polarization setup colinear with an intense control field to store and retrieve any arbitrary polarization state by addressing a Λ-type energy level scheme in a 87Rb vapor cell. To achieve a signal-to-background ratio at the few photon level sufficient for polarization tomography of the retrieved state, the intense control field is filtered out through an etalon filtrating system. We have developed an analytical model predicting the influence of the signal-to-background ratio on the fidelities and compared it to experimental data. Experimentally measured global fidelities have been found to follow closely the theoretical prediction as signal-to-background decreases. These results suggest the plausibility of employing room temperature memories to store photonic qubits at the single photon level and for future applications in long distance quantum communication schemes.

  16. Comparison of Model Prediction With Measurements of Galactic Background Noise at L-Band

    DEFF Research Database (Denmark)

    Le Vine, David M.; Abraham, Saji; Kerr, Yann H.;

    2005-01-01

    The spectral window at L-band (1.413 GHz) is important for passive remote sensing of surface parameters such as soil moisture and sea surface salinity that are needed to understand the hydrological cycle and ocean circulation. Radiation from celestial sources (mostly galactic) is strong in this w......The spectral window at L-band (1.413 GHz) is important for passive remote sensing of surface parameters such as soil moisture and sea surface salinity that are needed to understand the hydrological cycle and ocean circulation. Radiation from celestial sources (mostly galactic) is strong...... in this window, and an accurate accounting of this background radiation is often needed for calibration. This paper presents a comparison of the background radiation predicted by a model developed from modern radio astronomy measurements with measurements made with several modern L-band remote sensing...

  17. Influence from Polarized Galactic Background Noise on L-band Measurements of the Sea Surface Salinity

    DEFF Research Database (Denmark)

    Søbjærg, Sten Schmidl; Skou, Niels

    2004-01-01

    target area as well as clover leaf patterns have been measured, and both provide an azimuth signature of the ocean at a constant incidence angle. The resulting azimuth signatures show significant variations in all the three first Stokes parameters, and a correlation is found between the downwelling......The polarimetric EMIRAD radiometer, based on novel digital down conversion and detection techniques, has been installed on a C-130 aircraft from the Royal Danish. Air Force during the L-band Ocean Salinity Airborne Campaign (LOSAC) in 2001 and 2003. Full 360° circle flight patterns around the same...... galactic background signal and the measured results. The measured 3rd Stokes parameter has variations of the same order of magnitude as the two linear polarizations, and to verify this result, an experiment for direct observation of the sky over long time is set up. This experiment confirms the presence of...

  18. Seismic survey in southeastern Socorro Island: Background noise measurements, seismic events, and T phases

    Energy Technology Data Exchange (ETDEWEB)

    Valenzuela, Raul W [Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, D.F. (Mexico); Galindo, Marta [Comprehensive Nuclear-Test-Ban Treaty Organization, IMS, Vienna (Austria); Pacheco, Javier F; Iglesias, Arturo; Teran, Luis F [Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, D.F. (Mexico); Barreda, Jose L; Coba, Carlos [Facultad de Ingenieria, Benemerita Universidad Autonoma de Puebla, Puebla (Mexico)

    2005-01-15

    We carried out a seismic survey and installed five portable, broadband seismometers in the southeastern corner of Socorro Island during June 1999. Power spectral densities for all five sites were relatively noisy when compared to reference curves around the world. Power spectral densities remain constant regardless of the time of day, or the day of the week. Cultural noise at the island is very small. Quiet and noisy sites were identified to determine the best location of the T phase station to be installed jointly by the Universidad Nacional Autonoma de Mexico and the Comprehensive Nuclear-Test-Ban Treaty Organization. During the survey six earthquakes were recorded at epicentral distances between 42 km and 2202 km, with magnitudes between 2.8 and 7.0. Two small earthquakes (M{sub c} = 2.8 and 3.3) occurred on the Clarion Fracture Zone. The four largest and more distant earthquakes produced T waves. One T wave from an epicenter near the coast of Guatemala had a duration of about 100 s and a frequency content between 2 and 8 Hz, with maximum amplitude at about 4.75 Hz. The Tehuacan earthquake of June 15, 1999 (M{sub w} = 7.0) produced arrivals of P {yields} T and S {yields} T waves, with energy between 2 Hz and 3.75 Hz. The earthquake occurred inland within the subducted Cocos plate at a depth of 60 km; a significant portion of the path was continental. Seismic P and S waves probably propagated upward in the subducted slab, and were converted to acoustic energy at the continental slope. Total duration of the T phase is close to 500 s and reaches its maximum amplitude about 200 s after the P {yields} T arrival. The T wave contains energy at frequencies between 2 and 10 Hz and reaches its maximum amplitude at about 2.5 Hz. T phases were also recorded from two earthquakes in Guerrero, Mexico and in the Rivera Fracture Zone. [Spanish] En junio de 1999 instalamos cinco sismometros portatiles de banda ancha en el sureste de la Isla Socorro. Se encontro que las densidades

  19. How to coadd images? II. A coaddition image that is optimal for any purpose in the background dominated noise limit

    CERN Document Server

    Zackay, Barak

    2015-01-01

    Image coaddition is one of the most basic operations that astronomers perform. In Paper~I, we presented the optimal ways to coadd images in order to detect faint sources and to perfrom flux measurements under the assumption that the noise is approximately Gaussian. Here, we build on these results and derive from first principles a coaddition technique which is optimal for any hypothesis testing and measurement (e.g., source detection, flux or shape measurements and star/galaxy separation), in the background-noise-dominated case. This method has several important properties. The pixels of the resulting coadd image are uncorrelated. This image preserves all the information (from the original individual images) on all spatial frequencies. Any hypothesis testing or measurement that can be done on all the individual images simultaneously, can be done on the coadded image without any loss of information. The PSF of this image is typically as narrow, or narrower than the PSF of the best image in the ensemble. Moreov...

  20. Implications of conspecific background noise for features of blue tit, Cyanistes caeruleus , communication networks at dawn

    DEFF Research Database (Denmark)

    Poesel, Angelika; Dabelsteen, Torben; Pedersen, Simon Boel

    2007-01-01

    Abstract  Communication among animals often comprises several signallers and receivers within the signal's transmission range. In such communication networks, individuals can extract information about differences in relative performance of conspecifics by eavesdropping on their signalling...... interactions. In songbirds, information can be encoded in the timing of signals, which either alternate or overlap, and both male and female receivers may utilise this information when engaging in territorial interactions or making reproductive decisions, respectively. We investigated how conspecific...... background noise at dawn may overlay and possibly constrain the perception of such singing patterns. We simulated a small communication network of blue tits, Cyanistes caeruleus, at dawn in spring. Two loudspeakers simulated a singing interaction which was recorded from four different receiver positions...

  1. Subtraction of low level background noise in measurement of enriched uranium using CdZnTe detector

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Jung-ki; Kwak, Sung-Woo [Korea Institute of Nuclear Nonproliferation and Control, Daejeon (Korea, Republic of)

    2015-05-15

    In this study, it have been the present work new samples lead shield of 5 cm and copper filter plates with 100x100 mm{sup 2} area and the thickness of 0.2 - 2 mm were prepared, it have been undertaken to evaluate the former samples as γ-ray shields. Experimentally values of mass attenuation coefficients have been compared with theoretically calculated values of these samples using Monte Carlo simulation. The present study demonstrates that the combination of CZT measurements and computer simulations helps us understand the radiation production by shielding materials and the decrease of low-level background noise by Cu-filter. We carried out simulation of shielding using Cu-filter and verified the method by experimental measurement. We did not observe an evolution of relative ratio of low and high energy region using more than thickness of 1.6mm but only count rates deceased.

  2. Emergence of a signal from background noise in the "memory of water" experiments: how to explain it?

    Science.gov (United States)

    Beauvais, Francis

    2012-01-01

    After more than 20 years, the case of the "memory of water" still has not been resolved satisfactorily. After the affair with the journal Nature, Benveniste extended his results on high dilutions to an "electromagnetic biology" and then to a "digital biology," where electromagnetic signals supposed to be emitted from biologically active solutions were said to be stored on magnetic memories. Although the results obtained by Benveniste and coworkers were obvious, the difficulties in reproducibility by other teams created doubt of the reality of the alleged phenomenon. In a first step, we analyzed a set of experiments obtained by Benveniste's team in the 1990s. We quantified the relationship between "expected" effects (ie, labels of the tested samples) and apparatus outcomes, and we defined the experimental conditions to observe significant correlations. We concluded that the results of these experiments were related to experimenter-dependent correlations, which did not support the initial "memory of water" hypothesis. The fact that a signal emerged from background noise, however, remained puzzling. Therefore, in a second step, we described Benveniste's experiments according to the relational interpretation of quantum physics of C. Rovelli. In this interpretation, the state of a system is observer-dependent and the collapse of the wave function appears only in the states relative to a given observer. This interpretation allowed us to elaborate a model describing Benveniste's experiments in which the emergence of a signal from background noise was described by the entanglement of the experimenter with the observed system. In conclusion, the pursuit of the experimental "proof" to support the "memory of water" hypothesis has prevented other interpretations. Although our hypothesis does not definitely dismiss the possibility of "memory of water," the experimenter-dependent entanglement could be an attractive alternative interpretation of Benveniste's experiments. PMID

  3. Impact of Improved Heat Sinking of an X-Ray Calorimeter Array on Crosstalk, Noise, and Background Events

    Science.gov (United States)

    Kilbourne, C. A.; Adams, J. S.; Brekosky, R. P.; Chervenak, J. A.; Chiao, M. P.; Kelley, R. L.; Kelly, D. P.; Porter, F. S.

    2011-01-01

    The x-ray calorimeter array of the Soft X-ray Spectrometer (SXS) of the Astro-H satellite will incorporate a silicon thermistor array produced during the development of the X-Ray Spectrometer (XRS) of the Suzaku satellite. On XRS, inadequate heat sinking of the array led to several non-ideal effects. The thermal crosstalk, while too small to be confused with x-ray signals, nonetheless contributed a noise term that could be seen as a degradation in energy resolution at high flux. When energy was deposited in the silicon frame around the active elements of the array, such as by a cosmic ray, the resulting pulse in the temperature of the frame resulted in coincident signal pulses on most of the pixels. In orbit, the resolution was found to depend on the particle background rate. In order to minimize these effects on SXS, heat-sinking gold was applied to areas on the front and back of the array die, which was thermally anchored to the gold of its fanout board via gold wire bonds. The thermal conductance from the silicon chip to the fanout board was improved over that of XRS by an order of magnitude. This change was sufficient for essentially eliminating frame events and allowing high-resolution to be attained at much higher counting rates. We will present the improved performance, the measured crosstalk, and the results of the thermal characterization of such arrays.

  4. Long-term ELF background noise measurements, the existence of window regions, and applications to earthquake precursor emission studies

    Science.gov (United States)

    Dea, Jack Y.; Hansen, Peder M.; Boerner, Wolfgang-M.

    1993-04-01

    A Low Frequency Monitoring Network has been under development at Naval Command, Control and Ocean Surveillance Center (NCCOSC), Research, Development, Test and Evaluation Division (RDT & E), San Diego, CA, for the last 2 years. Originally developed to monitor space vehicle induced signatures in the 5-12 Hz region, the network now includes monitoring of anomolous broadband signals in the 0.1-20 Hz region that often precede the occurrence of nearby earthquakes. Observations of such events have led to a hypothesis that geological signals are normally present in the ULF (ultra-low frequency, less than 3 Hz) and ELF (extremely low frequency, 3-3000 Hz) bands in addition to the generally accepted signals from micropulsations and lightning discharges. In Southern California, the geological signals are best observed in the 'polarimetric window' regions of (i) 2-5 Hz using horizontally oriented magnetic sensors and, (ii) 2-20 Hz using vertically oriented magnetic sensors. To determine the significance of anomalous events, we conducted a statistical study of the background noise levels. Observations of daily records over a span of several months indicated that the background level in the 1-20 Hz region is stationary. Stationarity is not true below 1 Hz. The APD (amplitude probability density) of 2-12 Hz signals was found to be surprisingly close to a Gaussian distribution. These two results indicated that a determination of long-term averages and variances would be meaningful. Long-term averages and variances were obtained and were used to develop alert-level criteria. Typical deviations over the course of several hours are 1 to 2 dB. The alert-level criteria are used as input parameters in our Automated Monitoring System (AMS), a computerized monitoring and real-time analysis system. The alert levels warn the operator when unusual events are occurring. High alert-levels in conjunction with the fulfilment of several other conditions often presage the occurrence of an

  5. Double beta radioactivity and physics of the neutrino. Study of the background noise at 3 MeV in the search of 100Mo beta beta decay

    International Nuclear Information System (INIS)

    Double beta decay without neutrino emission provides a test of the mass and nature of neutrinos (Majorana or Dirac). Experimental proof would be the observation of a peak at the transition energy in the spectrum of the two emitted electrons. The expected half-life of the process is extremely long (about 1025 years for 100Mo). So, being thus, it is very important to get a good knowledge of the origins and contributions of background noise in the region where the signal could occur. The main origins of the background noise in the region where the signal could occur. The main origins of the background noise are found to be e+ - e- pairs induced by heavy energy gamma rays. These gamma rays follow the thermal neutron capture by the components of the detector. Another factor in the production of background noise is natural radio-activity. For example, the presence of Radon in the laboratory has been observed to produce deposits of 214Bi on the sides of the detector. Data taken with the NEMO 2 prototype and an enriched molybdenum source foil indicates that the background limit reached is of the order of 1 event per year in the 3 MeV region. Results of this work have proven the necessity to have a magnetic field in NEMO 3 in order to reject e+ - e-pairs. (author)

  6. Accuracy of joint measurement of time and direction of arrival of radio signal against the background of narrow-band influence and noise

    OpenAIRE

    Fesun, A. M.; Goloskokova, L. Sh.

    2009-01-01

    The mean square errors of joint measurement of delay interval and direction of arrival of signal against the background of external narrow-band influence and internal noise are obtained. The measurement accuracy of parameters with respect to space-time characteristics of radiation is calculated.

  7. Reducing the Effects of Background Noise during Auditory Functional Magnetic Resonance Imaging of Speech Processing: Qualitative and Quantitative Comparisons between Two Image Acquisition Schemes and Noise Cancellation

    Science.gov (United States)

    Blackman, Graham A.; Hall, Deborah A.

    2011-01-01

    Purpose: The intense sound generated during functional magnetic resonance imaging (fMRI) complicates studies of speech and hearing. This experiment evaluated the benefits of using active noise cancellation (ANC), which attenuates the level of the scanner sound at the participant's ear by up to 35 dB around the peak at 600 Hz. Method: Speech and…

  8. Neural Segregation of Concurrent Speech: Effects of Background Noise and Reverberation on Auditory Scene Analysis in the Ventral Cochlear Nucleus.

    Science.gov (United States)

    Sayles, Mark; Stasiak, Arkadiusz; Winter, Ian M

    2016-01-01

    Concurrent complex sounds (e.g., two voices speaking at once) are perceptually disentangled into separate "auditory objects". This neural processing often occurs in the presence of acoustic-signal distortions from noise and reverberation (e.g., in a busy restaurant). A difference in periodicity between sounds is a strong segregation cue under quiet, anechoic conditions. However, noise and reverberation exert differential effects on speech intelligibility under "cocktail-party" listening conditions. Previous neurophysiological studies have concentrated on understanding auditory scene analysis under ideal listening conditions. Here, we examine the effects of noise and reverberation on periodicity-based neural segregation of concurrent vowels /a/ and /i/, in the responses of single units in the guinea-pig ventral cochlear nucleus (VCN): the first processing station of the auditory brain stem. In line with human psychoacoustic data, we find reverberation significantly impairs segregation when vowels have an intonated pitch contour, but not when they are spoken on a monotone. In contrast, noise impairs segregation independent of intonation pattern. These results are informative for models of speech processing under ecologically valid listening conditions, where noise and reverberation abound. PMID:27080680

  9. Tunnel diode amplifiers and their background noise as a function of the polarization point, the temperature, and the bandwidth

    International Nuclear Information System (INIS)

    The author presents mathematical and graphical methods for the study of the stability of tunnel diode circuits. He gives an application to the realization of three amplifiers. Then he describes a theoretical and experimental investigation of the noise of these amplifiers and of its variations with the bias, the temperature and the bandwidth. (author)

  10. Techniques to improve the accuracy of noise power spectrum measurements in digital x-ray imaging based on background trends removal

    International Nuclear Information System (INIS)

    Purpose: Noise characterization through estimation of the noise power spectrum (NPS) is a central component of the evaluation of digital x-ray systems. Extensive works have been conducted to achieve accurate and precise measurement of NPS. One approach to improve the accuracy of the NPS measurement is to reduce the statistical variance of the NPS results by involving more data samples. However, this method is based on the assumption that the noise in a radiographic image is arising from stochastic processes. In the practical data, the artifactuals always superimpose on the stochastic noise as low-frequency background trends and prevent us from achieving accurate NPS. The purpose of this study was to investigate an appropriate background detrending technique to improve the accuracy of NPS estimation for digital x-ray systems. Methods: In order to achieve the optimal background detrending technique for NPS estimate, four methods for artifactuals removal were quantitatively studied and compared: (1) Subtraction of a low-pass-filtered version of the image, (2) subtraction of a 2-D first-order fit to the image, (3) subtraction of a 2-D second-order polynomial fit to the image, and (4) subtracting two uniform exposure images. In addition, background trend removal was separately applied within original region of interest or its partitioned sub-blocks for all four methods. The performance of background detrending techniques was compared according to the statistical variance of the NPS results and low-frequency systematic rise suppression. Results: Among four methods, subtraction of a 2-D second-order polynomial fit to the image was most effective in low-frequency systematic rise suppression and variances reduction for NPS estimate according to the authors' digital x-ray system. Subtraction of a low-pass-filtered version of the image led to NPS variance increment above low-frequency components because of the side lobe effects of frequency response of the boxcar filtering

  11. The Influence of Photon Attenuation on Tumor-to-Background and Signal-to-Noise Ratios for SPECT Imaging

    OpenAIRE

    Soares, Edward J.; King, Michael A.; Byrne, Charles L.; Gifford, Howard C.; Lehovich, Andre

    2007-01-01

    Expanding on the work of Nuyts et. al [1], Bai et. al. [2], and Bai and Shao [3], who all studied the effects of attenuation and attenuation correction on tumor-to-background ratios and signal detection, we have derived a general expression for the tumor-to-background ratio (TBR) for SPECT attenuated data that have been reconstructed with a linear, non-iterative reconstruction operator O. A special case of this is when O represents discrete filtered back-projection (FBP). The TBR of the recon...

  12. Acoustic Emission Detection Applications in High Background Noise Environments%声发射技术在高噪声背景下的检测应用

    Institute of Scientific and Technical Information of China (English)

    田亚团; 蒋仕良; 李杰; 李东

    2013-01-01

    This article describes the acoustic emission (AE) detection technology in high background noise environments.The AE technique was used for on-line detection and analysis of the reformed parts of a gasifier and the acoustic emission test results were re-inspected by conventional NDT methods.The results showed that acoustic emission testing technology could have good correspondence with conventional NDT methods in detecting the defects,which proved the feasibility and effectiveness of acoustic emission in high background noise.The results could provide reference for AE test of similar large-scale petrochemical equipment.%介绍了在高噪声背景下,对某台气化炉改造部位进行声发射检测分析的情况,并采用常规无损检测方法对声发射检测结果进行了复验.结果表明,声发射检测技术与常规无损检测方法发现的缺陷有良好的对应关系,证明声发射检测技术在高噪声背景下的可行性和有效性,为类似大型石化设备声发射检测提供了参考.

  13. Search for Higgs bosons in 2 lepton events and validation of a background noise detector in the DELPHI experiment

    International Nuclear Information System (INIS)

    This thesis presents two studies made within the DELPHI experiment in the context of the energy rise of the LEP collider. The first study concerns the setting up of a silicon plate detector that allows a continuous measurement of the background generated by the beams, particularly synchrotron radiation, the intensity of which increases strongly with the beam energy. This silicon monitor ensures a better safety of the more fragile DELPHI sub-detectors, especially the Time Projection Chamber, and gives a very precise measurement of the time of flight and energy of particles (2.1 ns and 3.6 keV resolution), thus allowing to identify the machine elements from which the background originates. The second study is devoted to the search for a neutral Higgs boson, produced in association with a Z boson decaying into an electron or a muon pair; we have searched for Higgs boson decays in b quarks, τ leptons or into invisible decay products as it is predicted by some supersymmetry scenarios. No signal has been observed in the 54 and 158 pb-1 data recorded at √s=183 and 189 GeV. Combining this result with those from other search channels, the hypothesis for a standard Higgs boson with a mass less than 94.5 GeV/c2 can be excluded at more than 95 % confidence level. In the frame of the Minimal Supersymmetric Model, this limit becomes 82.4 GeV/c2, independently of the free parameter tanβ. Finally, as far as invisible decays are concerned, the limit becomes 90.2 GeV/c2, independently of the branching ratio into invisible decay products. (author)

  14. Fast Estimator of Primordial Non-Gaussianity from Temperature and Polarization Anisotropies in the Cosmic Microwave Background II: Partial Sky Coverage and Inhomogeneous Noise

    CERN Document Server

    Yadav, Amit P S; Wandelt, Benjamin D; Liguori, Michele; Hansen, Frode K; Matarrese, Sabino

    2007-01-01

    In our recent paper (Yadav et al. 2007) we described a fast cubic (bispectrum) estimator of the amplitude of primordial non-Gaussianity of local type, f_{NL}, from a combined analysis of the Cosmic Microwave Background (CMB) temperature and E-polarization observations. In this paper we generalize the estimator to deal with a partial sky coverage as well as inhomogeneous noise. Our generalized estimator is still computationally efficient, scaling as O(N^3/2) compared to the O(N^5/2) scaling of the brute force bispectrum calculation for sky maps with N pixels. Upcoming CMB experiments are expected to yield high-sensitivity temperature and E-polarization data. Our generalized estimator will allow us to optimally utilize the combined CMB temperature and E-polarization information from these realistic experiments, and to constrain primordial non-Gaussianity.

  15. The Background Noise (Book review)

    OpenAIRE

    Klaff, Lesley D

    2010-01-01

    This is a review of Anthony Julius's 'Trials of the Diaspora: A History of Anti-Semitism in England' (Oxford University Press 2010). It critiques and praises Julius's detailed, scholarly and fluent account of four anti-Semitisms, each with a uniquely English provenance: the anti-Semitism of medieval England; English literary anti-Semitism; modern English anti-Semitism; and contemporary anti-Zionism.

  16. Analysis of the Characteristics of the Background Noise from a Nuclear Explosion Monitoring%核爆次声背景噪声信号特征分析

    Institute of Scientific and Technical Information of China (English)

    青建华; 程先友; 庞新良

    2013-01-01

    Infrasound monitoring is one of the four monitoring technologies stipulated in " The Comprehensive Nuclear-Test-Ban Treaty".According to the interest in the understanding of background noise during nuclear explosion infrasound monitoring,the discussion is concentrated on the infrasound caused by earthquake,volcanic eruption,lightning,gale and so on.It's very important to understand these characteristics for developing nuclear explosion infrasound monitoring.%核爆炸次声监测技术是《全面禁止核试验条约》规定的监测技术手段之一,主要用来监测大气层中的核爆炸.根据核爆次声监测对背景噪声信号影响的关注,重点介绍了地震、火山喷发、闪电、大风等非核爆次声信号的特征,了解这些特征对于开展核爆次声监测有益.

  17. Designing acoustics for linguistically diverse classrooms: Effects of background noise, reverberation and talker foreign accent on speech comprehension by native and non-native English-speaking listeners

    Science.gov (United States)

    Peng, Zhao Ellen

    The current classroom acoustics standard (ANSI S12.60-2010) recommends core learning spaces not to exceed background noise level (BNL) of 35 dBA and reverberation time (RT) of 0.6 second, based on speech intelligibility performance mainly by the native English-speaking population. Existing literature has not correlated these recommended values well with student learning outcomes. With a growing population of non-native English speakers in American classrooms, the special needs for perceiving degraded speech among non-native listeners, either due to realistic room acoustics or talker foreign accent, have not been addressed in the current standard. This research seeks to investigate the effects of BNL and RT on the comprehension of English speech from native English and native Mandarin Chinese talkers as perceived by native and non-native English listeners, and to provide acoustic design guidelines to supplement the existing standard. This dissertation presents two studies on the effects of RT and BNL on more realistic classroom learning experiences. How do native and non-native English-speaking listeners perform on speech comprehension tasks under adverse acoustic conditions, if the English speech is produced by talkers of native English (Study 1) versus native Mandarin Chinese (Study 2)? Speech comprehension materials were played back in a listening chamber to individual listeners: native and non-native English-speaking in Study 1; native English, native Mandarin Chinese, and other non-native English-speaking in Study 2. Each listener was screened for baseline English proficiency level, and completed dual tasks simultaneously involving speech comprehension and adaptive dot-tracing under 15 acoustic conditions, comprised of three BNL conditions (RC-30, 40, and 50) and five RT scenarios (0.4 to 1.2 seconds). The results show that BNL and RT negatively affect both objective performance and subjective perception of speech comprehension, more severely for non

  18. Design of exponent type space matched filter based on analysis of background noise Fourier spectrum%基于噪音谱分析的新型指数空间匹配滤波器设计

    Institute of Scientific and Technical Information of China (English)

    高鸿启; 沈学举; 甘厚吉

    2011-01-01

    In order to limit the influence of background noise on correlation spot on the output correlation plane , the Fourier spectrum of the matched filter function and the background noise were compared, and the amplitude of the matched filter was nonlinearly modulated based on the exponent function relying on the Founer spectrum of the background noise. It enables the filter to reduce the transmittance in the area of the intense noise Fourier spectrum relative to the transmittance for input image Fourier spectrum. The signal-to-noise ratio on the output correlation plane was improved and the detection of the correlation spots was realized. The results of computer simulation show that the correlation peak value reduces 2. 28 times and the signal-to-noise ratio increases 3 times when m changes into 1. 2 from 0. The results of simulation and experiment show that the anti-noise capability of exponent type space matched filter is imprved obviously.%光学相关识别过程中,为减小输入场景中背景噪音对输出相关点的影响,通过分析背景噪音和目标图像的傅里叶谱,在匹配滤波函数中引入一由背景噪音傅里叶谱确定的指数函数,通过指数函数对匹配滤波函数振幅进行非线性调制,使设计的指数型空间匹配滤波器对背景噪音谱透过率小于目标图像谱透过率,从而增加输出相关平面上的信噪比,以实现相关点的正确探测.模拟结果表明当参量m由0增加到1.2时,相关峰值下降2.28倍,信噪比增加3倍.模拟和实验结果均表明:与纯相位匹配滤波器相比其抗噪能力得到明显改善.

  19. Variations in voice level and fundamental frequency with changing background noise level and talker-to-listener distance while wearing hearing protectors: A pilot study

    DEFF Research Database (Denmark)

    Bouserhal, Rachel E.; MacDonald, Ewen; Falk, Tiago H.;

    2016-01-01

    concern for people wearing hearing protection devices (HPD). Although practical, radio communication is cumbersome, as it does not distinguish designated receivers. A smarter radio communication protocol must be developed to alleviate this problem. Thus, it is necessary to model speech production in noise...... while wearing HPDs. Such a model opens the door to radio communication systems that distinguish receivers and offer more efficient communication between persons wearing HPDs. Design: This paper presents the results of a pilot study aimed to investigate the effects of occluding the ear on changes in...... voice level and fundamental frequency in noise and with varying talker-to-listener distance. Study sample: Twelve participants with a mean age of 28 participated in this study. Results: Compared to existing data, results show a trend similar to the open ear condition with the exception of the occluded...

  20. Noise suppression by noise

    OpenAIRE

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

    2001-01-01

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

  1. Study of the background noise generated by the accelerator PEP-2 with a CsI(Na) scanning ring. Study of mass difference between B neutral mesons by using BABAR detector and DI-leptons events

    International Nuclear Information System (INIS)

    The first part of this report is dedicated to the CP-violation in the sector of B quarks and to its experimental proof through 2 major equipment: the B meson factory PEP-2 and the detector BABAR. The second part deals with the background noise generated by PEP-2. The third part presents the study of the oscillations of neutral B mesons with the detector BABAR. The study of the background noise shows important differences between the experimental data and the simulation. These differences are thought to be due on one hand to the lack of accuracy of pressure models that set the normalisation of the simulated background noise, and on the other hand to the absence of simulation of particles that undergo Coulomb diffusion and do more than a lap before bumping into the void tube. The second hypothesis is backed by the evaluation of the collimation effect of the beam that appears to be more important in experimental data than in the simulation. Among the main results given by the BABAR collaboration, the measurement of the oscillation frequency of the neutral B meson is very important. This measurement is based on semi-leptonic decays of B mesons in order to tag the favour of neutral B mesons at the very moment of their decay. The data analysis was performed over 2.3 106 decays of B meson pairs and we obtained: Δmd = (0.495 ± 0.026 ± 0.023) ℎps-1. The accuracy on the value of Δmd could be improved by using tagging methods based on the semi-exclusive then exclusive reconstruction of neutral B mesons. (A.C.)

  2. CP violation in the K0 - anti K0 system. Study of the background noise minimization by means of a transition radiation detector

    International Nuclear Information System (INIS)

    This work has been performed for the NA31 experiment at CERN whose goal is a high precision mesurement of the parameter ε'/ε reflecting direct CP-violation in the K0 - anti K0 system. This work is concerned with the calibration and the study of the performance of the transition radiation detector, TRD, added recently to the experiment. The TRD provides an important increase in the pion/electrons separation. This allows a significant reduction in the systematic uncertainty in the background subtraction of the KL0 to two charged pions decay mode which is dominated by semileptonics decays. A complete calibration of this detector has been performed. Energy pulseheight response for various detectors parameters are reviewed. After all corrections, electron rejection efficiency is shown. We analyse then, the semi-leptonic charged background

  3. Study of the neutron background noise generated by muons in the Edelweiss-2 experiment; Etude du bruit de fond neutron induit par les muons dans l'experience EDELWEISS-2

    Energy Technology Data Exchange (ETDEWEB)

    Chabert, L

    2004-07-01

    This thesis contributes to the Edelweiss experiment whose aim is to detect interactions between neutralinos and target nuclei. Bolometers used in Edelweiss combine the detection of phonons with the detection of electric charges generated by the energy deposition. This double detection enables us to discard background signals due to electronic interactions and soon detection sensitivity of the experiment will be limited by the neutron background noise due to residual cosmic muons. This work is dedicated to a detailed study of muon inelastic interactions and the consequent production of neutrons. Simulations show that the expected neutron flux is so high that the direct detection of muons is required in order to link it to the neutron signal issued by the bolometer. Results from simulations show that plastic scintillators might be the main components of the muon detector.

  4. Radiological measurements at low signal-to-noise ratios. Statistical considerations for background measurements and suppression; Messungen an der Erkennungsgrenze des Messsystems. Statistische Betrachtungen zu Hintergrundmessungen und -korrekturen

    Energy Technology Data Exchange (ETDEWEB)

    Brandl, A.; Mann, J.; Labrake, M. [Colorado State Univ., Fort Collins, CO (United States). Environmental and Radiological Health Sciences; Klumpp, J. [Los Alamos National Laboratory, Los Alamos, NM (United States). Environment, Safety, Health Directorate

    2015-07-01

    Low-level radiological measurements of environmental samples, food stuffs and drinking water, or in screening for orphan radiological sources or clandestine nuclear materials often challenge the measurement capabilities of radiological instruments. The decision threshold serves as differentiating factor between ''signal'' and ''background'' and is determined by standardized methodologies according to ISO 11929. These methodologies are extended to include novel statistical considerations where continuous measurements allow for a more accurate, and possibly lower decision threshold. Both classical as well as Bayesian statistics for correlated measurements from detector time series or from multiple combined instruments (i.e., detectors in a network, individual pixels on a detector unit) seem promising. Practical applications of statistical algorithms could improve detection capabilities for radiological instruments in environmental radiology, could lead to earlier identification of orphan sources, or could allow for dose reduction in medical imaging procedures.

  5. Noise Pollution

    Science.gov (United States)

    ... Overview » Title IV - Noise Pollution Title IV - Noise Pollution The 1990 Clean Air Act Amendments added a ... abatement 7642 Authorization of appropriations What is Noise Pollution? The traditional definition of noise is “unwanted or ...

  6. Noise Control and Noise Evaluation in Aircraft Engines

    OpenAIRE

    石井, 達哉; Ishii, Tatsuya

    2002-01-01

    Aircraft engine noise emitted for example by the jet exhaust, fan, compressor, turbine and combustor is the predominant factor in total aircraft noise during take-off and landing. As a result of enormous efforts to alleviate engine noise, noise levels have been improved by more than 20 dB compared to the first generation of airliners. However, the growing volume of air transport means that further noise reduction is still required. With this background, we decided to concentrate on two techni...

  7. 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....

  8. 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...

  9. Noise Pollution

    Science.gov (United States)

    ... EPA Home Air and Radiation Noise Pollution Noise Pollution This page has moved. You should be immediately ... gov/clean-air-act-overview/title-iv-noise-pollution Local Navigation Air & Radiation Home Basic Information Where ...

  10. Noise and public health.

    Science.gov (United States)

    Lipscomb, D M; Roettger, R W

    1976-01-01

    Environmental noise has increased to the point that it affects large numbers of people. The most consistently demonstrated health effect of exposure to noise is hearing impairment. Other effects, such as stress reaction, irritability, fatigue and disturbances to physiologic function have been seen in laboratory research but are highly individualized and restricted to such specific populations as industrial workers. Rising background sound levels in communities due to increased traffic flow, industralization, work saving machinery, and other noise sources have caused community noise levels to become dangerously high. This factor is complicated by exposure to high sound level recreational activities with greater frequency and for longer periods. Recognizing the existence of the problem, governmental agencies have begun to identify the scope of the problem, to designate standards and regulations controlling noise sources, and to regulate allowable noise exposure for workers. PMID:10297834

  11. Noise prevention

    Science.gov (United States)

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

  12. Noise map

    OpenAIRE

    Němcová, Michaela

    2015-01-01

    The aim of this paper is to introduce the measurement of noise and create a noise map in a geographic information system. The first part is focused on describing the physical properties of sound in space, atmospheric and physiological acoustics. It also deals with the physiological effects of noise on the human body and technology needed for measure and process noise. Other part describes the structure of a geographic information system and noise map. The last part is about the practical crea...

  13. Snowmobile noise

    OpenAIRE

    Liikonen, Larri; Alanko, Mikko; Jokinen, Sirpa; Niskanen, Ilkka; Virrankoski, Lauri

    2007-01-01

    Planning snowmobiling routes and considering the possible need for off-road traffic restrictions requires that the noise impact of snowmobile traffic is known. The objective of this report was to take off-road readings in order to determine snowmobile noise emissions and the spread of noise from snowmobile routes into the environment. Based on the readings taken, it can be said that the noise zones created by snowmobile traffic are quite narrow at current traffic levels. Noise pollution ca...

  14. Industrial Noise

    OpenAIRE

    Mehran zolfaghari

    1996-01-01

    Various risk factors in industrial environments can affect hearing status and healthy in today’s modern society. Noise control and hearing conservation program is very crucial in preventing workers exposed to high levels of noise in the work places. In the current article we are going to discuss issues such as industrial noise control, noise characteristics and standards and techniques for noise control. Then the methods for individual hearing conservation and medical care will be described i...

  15. Adaptive noise

    OpenAIRE

    Viney, Mark; Reece, Sarah E.

    2013-01-01

    In biology, noise implies error and disorder and is therefore something which organisms may seek to minimize and mitigate against. We argue that such noise can be adaptive. Recent studies have shown that gene expression can be noisy, noise can be genetically controlled, genes and gene networks vary in how noisy they are and noise generates phenotypic differences among genetically identical cells. Such phenotypic differences can have fitness benefits, suggesting that evolution can shape noise ...

  16. Quantum Noise

    International Nuclear Information System (INIS)

    development of the topic is precise and well-organized. The derivations are written out in sufficient detail, without frustrating comments like 'it can be shown that'. The book is not quite self-contained, because it relies on the Handbook of Stochastic Methods for some background material (notably the issue of Ito versus Stratonovich). Still, one could very well use this book as a text for a course, supplying the background material to the students in some other form. Quantum Noise is now in its third edition. The second edition was a major expansion, including applications to laser cooling and quantum information processing. The third edition is a relatively minor upgrade, consisting mainly of pointers to recent literature. If you own the second edition, you might well skip this upgrade. If you do not yet own the book, or are still at edition 1, then I would enthusiastically recommend acquiring this handbook, regardless of whether you work in quantum optics or in another field of quantum physics. As I did, you might well find a new tool to attack your favourite problem. (book review)

  17. Background Material

    DEFF Research Database (Denmark)

    Zandersen, Marianne; Hyytiäinen, Kari; Saraiva, Sofia;

    2016-01-01

    This document serves as a background material to the BONUS Pilot Scenario Workshop, which aims to develop harmonised regional storylines of socio-ecological futures in the Baltic Sea region in a collaborative effort together with other BONUS projects and stakeholders.......This document serves as a background material to the BONUS Pilot Scenario Workshop, which aims to develop harmonised regional storylines of socio-ecological futures in the Baltic Sea region in a collaborative effort together with other BONUS projects and stakeholders....

  18. [The fetus and noise].

    Science.gov (United States)

    Brezinka, C; Lechner, T; Stephan, K

    1997-01-01

    From 23 weeks of gestation some and from 28 weeks all healthy fetuses are capable of reacting to sound stimulation. The intrauterine acoustic environment is dominated by maternal sounds--heartbeat, breathing, the mother's voice, borborygmi and sounds caused by body movements. Background noise is never below 28 dB and can rise to 84 dB when the mother is singing. Noises that are meant to reach the fetus must be louder than the background noise and must be of low frequency as high frequency sounds are damped by maternal tissue. Vibroacoustic stimulation tests (VAST) have become popular in pregnancy surveillance over the last 20 years, mostly using an artificial larynx. Advantages and problems of the various VAST protocols in fetal monitoring are discussed in the light of animal experiments and clinical studies. Health legislation laws in most countries forbid pregnant women to work in surroundings with a high noise level (80 dB continuous noise and/or rapid impulse noise changes of 40 dB). Whereas regulations for pregnant women are easy to enforce in industry, pregnant women employed in discos or performing as musicians spend most of their working day exposed to noise impact higher than the recommended limit. PMID:9483870

  19. Unjust noise

    OpenAIRE

    Paul Voice

    2009-01-01

    In this paper I argue that noise is a significant source of social harm and thoseharmed by noise often suffer not merely a misfortune but an injustice. I arguethat noise is a problem of justice in two ways; firstly, noise is a burden of socialcooperation and so the question of the distribution of this burden arises. And,secondly, some noises, although burdensome, are nevertheless just becausethey arise from practices that are ‘reasonable’. I offer a number of distinctions,between necessary an...

  20. Rotor noise

    Science.gov (United States)

    Schmitz, F. H.

    1991-01-01

    The physical characteristics and sources of rotorcraft noise as they exist today are presented. Emphasis is on helicopter-like vehicles, that is, on rotorcraft in nonaxial flight. The mechanisms of rotor noise are reviewed in a simple physical manner for the most dominant sources of rotorcraft noise. With simple models, the characteristic time- and frequency-domain features of these noise sources are presented for idealized cases. Full-scale data on several rotorcraft are then reviewed to allow for the easy identification of the type and extent of the radiating noise. Methods and limitations of using scaled models to test for several noise sources are subsequently presented. Theoretical prediction methods are then discussed and compared with experimental data taken under very controlled conditions. Finally, some promising noise reduction technology is reviewed.

  1. Gaussianity of LISA's confusion backgrounds

    International Nuclear Information System (INIS)

    Data analysis for the proposed Laser Interferometer Space Antenna (LISA) will be complicated by the huge number of sources in the LISA band. In the frequency band ∼10-4-2x10-3 Hz, galactic white dwarf binaries (GWDBs) are sufficiently dense in frequency space that it will be impossible to resolve most of them, and ''confusion noise'' from the unresolved Galactic binaries will dominate over instrumental noise in determining LISA's sensitivity to other sources in that band. Confusion noise from unresolved extreme-mass-ratio inspirals (EMRIs) could also contribute significantly to LISA's total noise curve. To date, estimates of the effect of LISA's confusion noise on matched-filter searches and their detection thresholds have generally approximated the noise as Gaussian, based on the central limit theorem. However in matched-filter searches, the appropriate detection threshold for a given class of signals may be located rather far out on the tail of the signal-to-noise probability distribution, where a priori it is unclear whether the Gaussian approximation is reliable. Using the Edgeworth expansion and the theory of large deviations, we investigate the probability distribution of the usual matched-filter detection statistic, far out on the tail of the distribution. We apply these tools to four somewhat idealized versions of LISA data searches: searches for EMRI signals buried in GWDB confusion noise, and searches for massive black hole binary signals buried in (i) GWDB noise, (ii) EMRI noise, and (iii) a sum of EMRI noise and Gaussian noise. Assuming reasonable short-distance cutoffs in the populations of confusion sources (since the very closest and hence strongest sources will be individually resolvable), modifications to the appropriate detection threshold, due to the non-Gaussianity of the confusion noise, turn out to be quite small for realistic cases. The smallness of the correction is partly due to the fact that these three types of sources evolve on quite

  2. Feminizing noise

    OpenAIRE

    Thompson, Marie

    2014-01-01

    Marie will explore the relationship between constructions of femininity and noise, which is understood here as an affective transformative force, rather than simply as unwanted sound. She will suggest that ‘feminine’ noises are often deemed negative; not because of what they mean, but as a result of the transformations they threaten to induce. Marie will raise questions around essentialism – does talking of a feminine or feminized noise require us to adopt an essentialist position, or can an ...

  3. NOISE REGULATION

    OpenAIRE

    Cristina Voican; Constantin Stanescu

    2012-01-01

    Noise regulation includes statutes or guidelines relating to sound transmission established by national, state or provincial and municipal levels of government. After the watershed passage of the United States Noise Control Act of 1972, other local and state governments passed further regulations. Although the UK and Japan enacted national laws in 1960 and 1967 respectively, these laws were not at all comprehensive or fully enforceable as to address generally rising ambient noise, enforceable...

  4. Detection of WIMPs in the Edelweiss experiment. Study of the radioactive background noise and measurements with bolometers; Recherche des wimp's du halo galactique dans l'experience edelweiss: etude du bas bruit radioactif et mesures a l'aide de bolometres a double detection ionisation/chaleur

    Energy Technology Data Exchange (ETDEWEB)

    Miramonti, L. [CEA/Saclay, Dept. d' Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l' Instrumentation Associee (DAPNIA), 91 - Gif-sur-Yvette (France)]|[Paris-11 Univ., 91 - Orsay (France)

    1999-11-01

    This thesis is dedicated to the detection of black matter in the form of WIMPs (weakly interacting massive particle). The characteristics of the interaction of WIMPs with matter are recalled. The very low number of expected events (<1 event/day.Kg) implies a radioactive background noise as weak as possible, furthermore the exponential decrease of the interacting rate with increasing energy calls for detectors with very low thresholds. Bolometers present advantages in WIMPs detection: i) very good resolution and very low thresholds, ii) very broad range of materials that can be used as absorber, the only requirements are: a crystal structure, to be a diamagnetic isolator and to have a convenient Debye temperature, iii) the possibility of detecting ionizing or non-ionizing particles, iv) the possibility of identifying the incident particle by measuring both temperature and another parameter such as ionization or scintillation, and v) the possibility of localizing the interaction inside the absorber by detecting ballistic phonons. The problematic of radioactive background noise is presented and the answers to the different sources (cosmic radiation,natural and artificial radioactivity) generating the background noise are examined. The materials used in the building of the detector and cryostat must be carefully chosen, they should be as little radioactive as possible. The test benches used to select materials for the Edelweiss experiment are described. The first measurements concerning the detectors Ge-4 and Ge-7 are presented. (A.C.)

  5. 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)

  6. Aircraft Noise

    Science.gov (United States)

    Michel, Ulf; Dobrzynski, Werner; Splettstoesser, Wolf; Delfs, Jan; Isermann, Ullrich; Obermeier, Frank

    Aircraft industry is exposed to increasing public pressure aiming at a continuing reduction of aircraft noise levels. This is necessary to both compensate for the detrimental effect on noise of the expected increase in air traffic and improve the quality of living in residential areas around airports.

  7. Noise Traders

    OpenAIRE

    James Dow; Gary Gorton

    2006-01-01

    Noise traders are agents whose theoretical existence has been hypothesized as a way of solving certain fundamental problems in Financial Economics. We briefly review the literature on noise traders. The is an entry for The New Palgrave: A Dictionary of Economics, 2nd Edition (Palgrave Macmillan: New York), edited by Steven N. Durlauf and Lawrence E. Blume, forthcoming in 2008.

  8. Chasing Noise

    OpenAIRE

    Mendel, Brock; Shleifer, Andrei

    2012-01-01

    We present a simple model in which rational but uninformed traders occasionally chase noise as if it were information, thereby amplifying sentiment shocks and moving prices away from fundamental values. We fill a theoretical gap in the literature by showing conditions under which noise traders can have an impact on market equilibrium disproportionate to their size in the market. The model offers a partial explanation for the surprisingly low market price of financial risk in the Spring of 2007.

  9. Crackling Noise

    OpenAIRE

    Sethna, James P.; Dahmen, Karin A.; Christopher R Myers

    2001-01-01

    Crackling noise arises when a system responds to changing external conditions through discrete, impulsive events spanning a broad range of sizes. A wide variety of physical systems exhibiting crackling noise have been studied, from earthquakes on faults to paper crumpling. Because these systems exhibit regular behavior over many decades of sizes, their behavior is likely independent of microscopic and macroscopic details, and progress can be made by the use of very simple models. The fact tha...

  10. Noise Bubbles

    OpenAIRE

    Mario Forni; Luca Gambetti; Marco Lippi; Luca Sala

    2014-01-01

    We introduce noisy information into a standard present value stock price model. Agents receive a noisy signal about the structural shock driving future dividend variations. The resulting equilibrium stock price includes a transitory component — the "noise bubble" — which can be responsible for boom and bust episodes unrelated to economic fundamentals. We propose a non-standard VAR procedure to estimate the structural shock and the "noise" shock, their impulse response functions and the bubble...

  11. Noise annoyance from wind turbines a review

    International Nuclear Information System (INIS)

    This study summarises present knowledge on noise perception and annoyances from wind turbines in areas were people live or spend recreation time. There are two main types of noise from a wind turbine: mechanical noise and aerodynamic noise. The aerodynamic noise emits from the rotor blades passing the air. It has a swishing character with a modulation that makes it noticeable from the background noise. This part of the wind turbine noise was found to be the most annoying. Field studies performed among people living in the vicinity of wind turbines showed that there was a correlation between sound pressure level and noise annoyance, but annoyance was also influenced by visual factors such as the attitude to wind turbines' impact on the landscape. Noise annoyance was found at lower sound pressure levels than in studies of annoyance from traffic noise. There is no scientific evidence that noise at levels created by wind turbines could cause health problems other than annoyance. No studies on noise from wind turbines in wilderness areas have been found, but the reaction to other noise sources such as aircraft have been studied. In recreational areas, the expectation of quietness is high among visitors, but wind turbines are, in contrary to aircraft, stationary and could be avoided by recreationists. The visual impact of wind turbines might though be the dominant source of annoyance. Regulations on noise from wind turbines are based on different principles. Some states, e.g. Denmark, have a special legislation concerning wind turbines, while others, like Sweden, have used recommendations originally developed for a different noise source. The noise level could either be absolute, as in Germany, or related to the background noise level as in France. This background noise level could be standardised, measured or related to wind speed

  12. A measurement method to discriminate aircraft fly-over noise

    OpenAIRE

    Genesca Francitorra, Meritxell; Romeu Garbí, Jordi; Pàmies Gómez, Teresa

    2010-01-01

    Currently aircraft noise monitoring systems use a mesh of single microphones distributed around an airport to continuously sample the noise level. This fact requires a manual process of aircraft noise event detection and classification in order to distinguish aircraft events from the rest of noise events in the recording. In the present paper a 3-meter-long 12-microphone linear array is used to automatically obtain a background noise free aircraft noise recording. The beamforming process sepa...

  13. Low voltage excess noise and shot noise in YBCO bicrystal junctions

    DEFF Research Database (Denmark)

    Constantinian, K.Y.; Ovsyannikov, G.A.; Borisenko, I.V.;

    2002-01-01

    The spectral density of background noise emitted by symmetric bicrystal YBaCuO Josephson junctions on sapphire substrates have been measured by a low noise cooled HEMT amplifier for bias voltages up to V approximate to 50 mV. At relatively low voltages V <4 mV a noticeable noise rise has been...

  14. Improving Gabor Noise

    OpenAIRE

    Lagae, Ares; Lefebvre, Sylvain; Dutré, Philip

    2011-01-01

    We have recently proposed a new procedural noise function, Gabor noise, which offers a combination of properties not found in existing noise functions. In this paper, we present three significant improvements to Gabor noise: (1) an isotropic kernel for Gabor noise, which speeds up isotropic Gabor noise with a factor of roughly two, (2) an error analysis of Gabor noise, which relates the kernel truncation radius to the relative error of the noise, and (3) spatially varying Gabor noise, which e...

  15. Relativistic Noise

    OpenAIRE

    Kapusta, Joseph; Mueller, Berndt; Stephanov, Misha

    2012-01-01

    The relativistic theory of hydrodynamic fluctuations, or noise, is derived and applied to high energy heavy ion collisions. These fluctuations are inherent in any space-time varying system and are in addition to initial state fluctuations. We illustrate the effects with the boost-invariant Bjorken solution to the hydrodynamic equations. Long range correlations in rapidity are induced by propagation of sound modes. The magnitude of these correlations are directly proportional to the viscositie...

  16. Skewed Noise

    OpenAIRE

    David Dillenberger; Uzi Segal

    2013-01-01

    Experimental evidence suggests that individuals who face an asymmetric distribution over the likelihood of a specific event might actually prefer not to know the exact value of this probability. We address these findings by studying a decision maker who has recursive, non-expected utility preferences over two-stage lotteries. For a binary lottery that yields the better outcome with probability p, we identify noise around p with a compound lottery that induces a probability distribution over t...

  17. Low noise road surfaces

    OpenAIRE

    Bolčina, Matjaž

    2014-01-01

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

  18. 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....

  19. Noise levels in an urban Asian school environment

    Directory of Open Access Journals (Sweden)

    Karen M.K. Chan

    2015-01-01

    Full Text Available Background noise is known to adversely affect speech perception and speech recognition. High levels of background noise in school classrooms may affect student learning, especially for those pupils who are learning in a second language. The current study aimed to determine the noise level and teacher speech-to-noise ratio (SNR in Hong Kong classrooms. Noise level was measured in 146 occupied classrooms in 37 schools, including kindergartens, primary schools, secondary schools and special schools, in Hong Kong. The mean noise levels in occupied kindergarten, primary school, secondary school and special school classrooms all exceeded recommended maximum noise levels, and noise reduction measures were seldom used in classrooms. The measured SNRs were not optimal and could have adverse implications for student learning and teachers′ vocal health. Schools in urban Asian environments are advised to consider noise reduction measures in classrooms to better comply with recommended maximum noise levels for classrooms.

  20. Yesterday's noise - today's signal

    International Nuclear Information System (INIS)

    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.)

  1. Nonequilibrium Spin Noise and Noise of Susceptibility

    OpenAIRE

    Schad, Pablo; Narozhny, Boris N.; Schön, Gerd; Shnirman, Alexander

    2014-01-01

    We analyze out-of-equilibrium fluctuations in a driven spin system and relate them to the noise of spin susceptibility. In the spirit of the linear response theory we further relate the noise of susceptibility to a $4$-spin correlation function in equilibrium. We show that, in contrast to the second noise (noise of noise), the noise of susceptibility is a direct measure of non-Gaussian fluctuations in the system. We develop a general framework for calculating the noise of susceptibility using...

  2. Radio Astronomy Explorer /RAE/. I - Observations of terrestrial radio noise.

    Science.gov (United States)

    Herman, J. R.; Caruso, J. A.; Stone, R. G.

    1973-01-01

    Radio Astronomy Explorer (RAE) I data are analyzed to establish characteristics of HF terrestrial radio noise at an altitude of about 6000 km. Time and frequency variations in amplitude of the observed noise well above cosmic noise background are explained on the basis of temporal and spatial variations in ionospheric critical frequency coupled with those in noise source distributions. It is shown that terrestrial radio noise regularly breaks through the ionosphere and reaches RAE with magnitudes 15 dB and more above cosmic noise background, on frequencies above the F-layer critical frequency.

  3. Noise-based communication and computing

    CERN Document Server

    Kish, Laszlo B

    2008-01-01

    We discuss the speed-error-heat triangle and related problems with rapidly increasing energy dissipation and error rate during miniaturization. These and the independently growing need of unconditional data security have provoked non-conventional approaches in the physics of informatics. Noise-based informatics is a potentially promising possibility which is the way how biological brains process the information. Recently, it has been shown that thermal noise and its electronically enhanced versions (Johnson-like noises) can be utilized as information carrier with peculiar properties. Relevant examples are Zero power (stealth) communication, Unconditionally secure communication with Johnson(-like) noise and Kirchhoff loop and Noise-driven computing. The zero power communication utilizes the equilibrium background noise in the channel to transfer information. The unconditionally secure communication is based on the properties of Johnson(-like) noise and those of a simple Kirchhoff's loop. The scheme utilizes on...

  4. Research on noise characteristics of industrial CT detecting system

    International Nuclear Information System (INIS)

    After analyzing the noise characteristics of industrial CT detecting system, this paper researches particularly the sources and influencing factors of the detecting system noise. Firstly, the general method of data processing was introduced. Secondly, a series of experiments based on low-energy industrial CT system were designed to test the signal power and noise power. Finally, experimental data were processed by statistical method, including computation of signal level, noise level and rule of noise. The experimental results show that: background is stable, noise level is related to integration time and amplification, noise introduced by DDC118 is low. The noise of detecting system is mainly caused by analog circuit and ray-source, which is composed of low frequency noise and white noise. Therefore, signal-to-noise ratio (SNR) can be improved by reducing system bandwidth. (authors)

  5. Hanford Site background: Part 3, Groundwater background

    International Nuclear Information System (INIS)

    This report presents and interprets groundwater background data collected from the unconfined aquifer beneath the Hanford Site, a U.S. Department of Energy complex located near Richland, Washington. Characterization of background composition is an important component of environmental characterization activities and serves as a basis for distinguishing the presence and significance of contamination. Background data can also be used to assess the levels of baseline risk to which humans or other receptors are typically exposed and to establish remediation goals. Evaluating background on a sitewide basis provides a consistent, technically defensible definition of background as opposed to determining area-specific background compositions for each waste management unit being considered for remediation across the Hanford Site

  6. Simulation of realistic background noise using multiple loudspeakers

    DEFF Research Database (Denmark)

    Song, Wookeun; Marschall, Marton; Gil Corrales, Juan David

    2015-01-01

    torso simulator (HATS) for sound reproduction, while the matrix inversion method optimizes the local sound field around a few target positions. The matrix inversion method had two conditions, i.e. with or without the extra processing steps described in ETSI TS 103 224; and three sets of optimization...

  7. Noise Reduction with Microphone Arrays for Speaker Identification

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, Z

    2011-12-22

    Reducing acoustic noise in audio recordings is an ongoing problem that plagues many applications. This noise is hard to reduce because of interfering sources and non-stationary behavior of the overall background noise. Many single channel noise reduction algorithms exist but are limited in that the more the noise is reduced; the more the signal of interest is distorted due to the fact that the signal and noise overlap in frequency. Specifically acoustic background noise causes problems in the area of speaker identification. Recording a speaker in the presence of acoustic noise ultimately limits the performance and confidence of speaker identification algorithms. In situations where it is impossible to control the environment where the speech sample is taken, noise reduction filtering algorithms need to be developed to clean the recorded speech of background noise. Because single channel noise reduction algorithms would distort the speech signal, the overall challenge of this project was to see if spatial information provided by microphone arrays could be exploited to aid in speaker identification. The goals are: (1) Test the feasibility of using microphone arrays to reduce background noise in speech recordings; (2) Characterize and compare different multichannel noise reduction algorithms; (3) Provide recommendations for using these multichannel algorithms; and (4) Ultimately answer the question - Can the use of microphone arrays aid in speaker identification?

  8. 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.

  9. Cosmic Infrared Background Fluctuations and Zodiacal Light

    CERN Document Server

    Arendt, Richard G; Moseley, S H; Mather, J

    2016-01-01

    We have performed a specific observational test to measure the effect that the zodiacal light can have on measurements of the spatial fluctuations of the near-IR background. Previous estimates of possible fluctuations caused by zodiacal light have often been extrapolated from observations of the thermal emission at longer wavelengths and low angular resolution, or from IRAC observations of high latitude fields where zodiacal light is faint and not strongly varying with time. The new observations analyzed here target the COSMOS field, at low ecliptic latitude where the zodiacal light intensity varies by factors of $\\sim2$ over the range of solar elongations at which the field can be observed. We find that the white noise component of the spatial power spectrum of the background is correlated with the modeled zodiacal light intensity. Roughly half of the measured white noise is correlated with the zodiacal light, but a more detailed interpretation of the white noise is hampered by systematic uncertainties that ...

  10. Noise and Hearing Protection

    Science.gov (United States)

    ... Meeting Calendar 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 ...

  11. Adaptive noise level estimation

    OpenAIRE

    Yeh, Chunghsin; Roebel, Axel

    2006-01-01

    We describe a novel algorithm for the estimation of the colored noise level in audio signals with mixed noise and sinusoidal components. The noise envelope model is based on the assumptions that the envelope varies slowly with frequency and that the magnitudes of the noise peaks obey a Rayleigh distribution. Our method is an extension of a recently proposed approach of spectral peak classification of sinusoids and noise, which takes into account a noise envelope model to improve the detection...

  12. Noise-Measuring Method

    DEFF Research Database (Denmark)

    Diamond, J. M.

    1965-01-01

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

  13. Wind turbine noise. Primary noise sources

    Energy Technology Data Exchange (ETDEWEB)

    Oerlemans, S.

    2011-04-15

    Wind is a clean, cheap, and inexhaustible source of energy. However, the noise from wind turbines constitutes an important hindrance for the widespread application of wind energy. As a result, there is considerable interest in wind turbine noise, from a number of angles. As public clamour grows from those living near turbines, and misinformation and disinformation begin to take root, there is a clear need for a scientifically accurate book to give an account of the noise generated, its effects on people, and possible remedies either through technology or legislation or both. The different potential source mechanisms are described and the theoretical characteristics of flowinduced sound from wind turbine blades are explained. The noise sources on wind turbines are characterized experimentally by means of wind tunnel and field experiments. Methods to predict and reduce wind turbine noise are discussed. The dominant noise source for typical modern large wind turbines is broadband trailing edge noise from the outer part of the blades. The swishing character of the sound can be explained by trailing edge noise directivity and convective amplification. A semi-analytical, semi-empirical prediction method can accurately predict the characteristics of wind turbine noise. Wind turbine noise can be halved by means of serrations, without adverse effects on the aerodynamic performance. The book is aimed at people with a personal or professional involvement in wind turbine noise, such as environmental health or public health practitioners, wind farm developers or informed wind farm supporters and objectors.

  14. Audience noise in concert halls during musical performances

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho; Marie, Pierre; Brunskog, Jonas

    2012-01-01

    Noise generated by the audience during musical performances is audible and sometimes disturbing. In this study, an attempt to estimate such audience noise was carried out. From the recordings of performances in five performance spaces (four concert halls and one opera house), probability density...... prediction models were made using the four orchestra concert halls, revealing that the audience noise level is significantly correlated with the technical background noise level. It is therefore concluded that a relaxation of the current background noise recommendations for concert halls is not recommended...

  15. Audience noise in concert halls during musical performances

    DEFF Research Database (Denmark)

    Marie, Pierre; Jeong, Cheol-Ho; Brunskog, Jonas;

    2012-01-01

    Noise generated by the audience during musical performances is audible and sometimes disturbing. In this study, an attempt to estimate such audience noise was carried out. From the recordings of performances in five performance spaces (four concert halls and one opera house), probability density...... prediction models were made using the four orchestra concert halls, revealing that the audience noise level is significantly correlated with the technical background noise level. It is therefore concluded that a relaxation of the current background noise recommendations for concert halls is not recommended....

  16. Radio Astronomy Explorer (RAE) 1 observations of terrestrial radio noise

    Science.gov (United States)

    Herman, J. R.; Caruso, J. A.

    1971-01-01

    Radio Astonomy Explorer (RAE) 1 data are analyzed to establish characteristics of HF terrestrial radio noise at an altitude of about 6000 km. Time and frequency variations in amplitude of the observed noise well above cosmic noise background are explained on the basis of temporal and spatial variations in ionospheric critical frequency coupled with those in noise source distributions. It is shown that terrestrial noise regularly breaks through the ionosphere and reaches RAE with magnitudes 15 or more db higher than cosmic noise background. Maximum terrestrial noise is observed when RAE is over the dark side of the Earth in the neighborhood of equatorial continental land masses where thunderstorms occur most frequently. The observed noise level is 30-40 db lower with RAE over oceans.

  17. Listen to the Noise: Noise Is Beneficial for Cognitive Performance in ADHD

    Science.gov (United States)

    Soderlund, Goran; Sikstrom, Sverker; Smart, Andrew

    2007-01-01

    Background: Noise is typically conceived of as being detrimental to cognitive performance. However, given the mechanism of stochastic resonance, a certain amount of noise can benefit performance. We investigate cognitive performance in noisy environments in relation to a neurocomputational model of attention deficit hyperactivity disorder (ADHD)…

  18. The astrophysical gravitational wave stochastic background

    Institute of Scientific and Technical Information of China (English)

    Tania Regimbau

    2011-01-01

    A stochastic background of gravitational waves with astrophysical origins may have resulted from the superposition of a large number of unresolved sources since the beginning of stellar activity.Its detection would put very strong constraints on the physical properties of compact objects, the initial mass function and star formarion history.On the other hand, it could be a ‘noise' that would mask the stochastic background of its cosmological origin.We review the main astrophysical processes which are able to produce a stochastic background and discuss how they may differ from the primordial contribution in terms of statistical properties.Current detection methods are also presented.

  19. Cosmic Infrared Background Fluctuations and Zodiacal Light

    Science.gov (United States)

    Arendt, Richard G.; Kashlinsky, A.; Moseley, S. H.; Mather, J.

    2016-06-01

    We performed a specific observational test to measure the effect that the zodiacal light can have on measurements of the spatial fluctuations of the near-IR background. Previous estimates of possible fluctuations caused by zodiacal light have often been extrapolated from observations of the thermal emission at longer wavelengths and low angular resolution or from IRAC observations of high-latitude fields where zodiacal light is faint and not strongly varying with time. The new observations analyzed here target the COSMOS field at low ecliptic latitude where the zodiacal light intensity varies by factors of ∼2 over the range of solar elongations at which the field can be observed. We find that the white-noise component of the spatial power spectrum of the background is correlated with the modeled zodiacal light intensity. Roughly half of the measured white noise is correlated with the zodiacal light, but a more detailed interpretation of the white noise is hampered by systematic uncertainties that are evident in the zodiacal light model. At large angular scales (≳100″) where excess power above the white noise is observed, we find no correlation of the power with the modeled intensity of the zodiacal light. This test clearly indicates that the large-scale power in the infrared background is not being caused by the zodiacal light.

  20. Noise, Health, and Architecture.

    Science.gov (United States)

    Beranek, Leo L.

    There is reasonable agreement that hearing impairment is related to noise exposure. This hearing loss due to noise is considered a serious health injury, but there is still difficulty in delineating the importance of noise related to people's general non-auditory well-being and health. Beside hearing loss, noise inhibits satisfactory speech…

  1. Can Noise Kill People?

    Institute of Scientific and Technical Information of China (English)

    刘玲娣

    2007-01-01

    Someone is singing next door,but you feel unhappy because her singing is just making a noise.We know that too much noise makes people feel terrible. Scientists are still trying to find out more about noise,but already it is known that a noise of over 85 decibels can make some people tired and anxious.

  2. Immersion Into Noise

    OpenAIRE

    Nechvatal, Joseph

    2011-01-01

    Joseph Nechvatal's Immersion Into Noise investigates multiple aspects of cultural noise by applying our audio understanding of noise to the visual, architectual and cognative domains. The author takes the reader through phenomenal aspects of the art of noise into algorithmic and network contexts, beginning in the Abside of the Grotte de Lascaux.

  3. Noise exposure and hypertension: investigation of a silent relationship

    OpenAIRE

    de Souza, Tatiana Cristina Fernandes; PÉRISSÉ, André Reynaldo Santos; Moura, Marisa

    2015-01-01

    Background Noise is an important occupational hazard worldwide and hypertension a well-known risk factor for cardiovascular disease, which is currently the greatest cause of disability retirement worldwide. The association between noise exposure and auditory effects is well documented in the biomedical literature, but the same is not true about exposure to different levels of noise and extra-auditory effects. It has been shown that noise exposure levels to be considered for non-auditory effec...

  4. Combined sensor noise-immunity

    Institute of Scientific and Technical Information of China (English)

    Vladimir A. Shchurov; Alexander V. Shchurov

    2002-01-01

    The paper presents statistical analysis of combined sensor noise-immunity while recording fluctuating tone against underwater dynamic noise background. The experimental data used for the analysis have been collected by a pair of four-component combined sensors centered at two depths, 150 and 300 m in deep water. Expressions for combined sensor signalto-noise ratio (SNR) for cross-spectral levels of signal and noise for both wide and narrow frequency bands have been derived. A combined sensor gain has been introduced in terms of ordinary single-point coherence function between acoustic pressure and particle velocity in acoustic wave. The estimates obtained experimentally evidence that SNR for a combined sensor with multiplicative data processing may exceed SNR for a hydrophone-based sensor by 15 to 16 dB at most for the horizontal channel of the combined sensor, and by 30 dB at most for the vertical channel (when opposite energy flows of signal and noise compensate one another).

  5. Non-Markovian noise

    International Nuclear Information System (INIS)

    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

  6. Study of the background noise generated by the accelerator PEP-2 with a CsI(Na) scanning ring. Study of mass difference between B neutral mesons by using BABAR detector and DI-leptons events; Etude du bruit de fond engendre par l'accelerateur PEP-2 avec un anneau de cristaux de CsI(Na). Etude des oscillations des mesons B neutres avec le detecteur BaBar en utilisant les evenements DI-Leptons

    Energy Technology Data Exchange (ETDEWEB)

    Domenico, G. de

    2000-06-14

    The first part of this report is dedicated to the CP-violation in the sector of B quarks and to its experimental proof through 2 major equipment: the B meson factory PEP-2 and the detector BABAR. The second part deals with the background noise generated by PEP-2. The third part presents the study of the oscillations of neutral B mesons with the detector BABAR. The study of the background noise shows important differences between the experimental data and the simulation. These differences are thought to be due on one hand to the lack of accuracy of pressure models that set the normalisation of the simulated background noise, and on the other hand to the absence of simulation of particles that undergo Coulomb diffusion and do more than a lap before bumping into the void tube. The second hypothesis is backed by the evaluation of the collimation effect of the beam that appears to be more important in experimental data than in the simulation. Among the main results given by the BABAR collaboration, the measurement of the oscillation frequency of the neutral B meson is very important. This measurement is based on semi-leptonic decays of B mesons in order to tag the favour of neutral B mesons at the very moment of their decay. The data analysis was performed over 2.3 10{sup 6} decays of B meson pairs and we obtained: {delta}m{sub d} = (0.495 {+-} 0.026 {+-} 0.023) {Dirac_h}ps{sup -1}. The accuracy on the value of {delta}m{sub d} could be improved by using tagging methods based on the semi-exclusive then exclusive reconstruction of neutral B mesons. (A.C.)

  7. Mechanics of underwater noise

    CERN Document Server

    Ross, Donald

    1976-01-01

    Mechanics of Underwater Noise elucidates the basic mechanisms by which noise is generated, transmitted by structures and radiated into the sea. Organized into 10 chapters, this book begins with a description of noise, decibels and levels, significance of spectra, and passive sonar equation. Subsequent chapters discuss sound waves in liquids; acoustic radiation fundamentals; wind-generated ocean ambient noise; vibration isolation and structural damping; and radiation by plate flexural vibrations. Other chapters address cavitation, propeller cavitation noise, radiation by fluctuating-force (dipo

  8. Polarization of Cosmic Microwave Background

    CERN Document Server

    Buzzelli, Alessandro; de Gasperis, Giancarlo; Vittorio, Nicola

    2016-01-01

    In this work we present an extension of the ROMA map-making code for data analysis of Cosmic Microwave Background polarization, with particular attention given to the inflationary polarization B-modes. The new algorithm takes into account a possible cross-correlated noise component among the different detectors of a CMB experiment. We tested the code on the observational data of the BOOMERanG (2003) experiment and we show that we are provided with a better estimate of the power spectra, in particular the error bars of the BB spectrum are smaller up to 20% for low multipoles. We point out the general validity of the new method. A possible future application is the LSPE balloon experiment, devoted to the observation of polarization at large angular scales.

  9. The Cosmic Background Imager 2

    CERN Document Server

    Taylor, Angela C; Allison, James R; Angelakis, Emmanouil; Bond, J Richard; Bronfman, Leonardo; Bustos, Ricardo; Davis, Richard J; Dickinson, Clive; Leech, Jamie; Mason, Brian S; Myers, Steven T; Pearson, Timothy J; Readhead, Anthony C S; Reeves, Rodrigo; Shepherd, Martin C; Sievers, Jonathan L

    2011-01-01

    We describe an upgrade to the Cosmic Background Imager instrument to increase its surface brightness sensitivity at small angular scales. The upgrade consisted of replacing the thirteen 0.9-m antennas with 1.4-m antennas incorporating a novel combination of design features, which provided excellent sidelobe and spillover performance for low manufacturing cost. Off-the-shelf spun primaries were used, and the secondary mirrors were oversized and shaped relative to a standard Cassegrain in order to provide an optimum compromise between aperture efficiency and low spillover lobes. Low-order distortions in the primary mirrors were compensated for by custom machining of the secondary mirrors. The secondaries were supported on a transparent dielectric foam cone to minimize scattering. The antennas were tested in the complete instrument, and the beam shape and spillover noise contributions were as expected. We demonstrate the performance of the telescope and the inter-calibration with the previous system using observ...

  10. Building Background Knowledge

    Science.gov (United States)

    Neuman, Susan B.; Kaefer, Tanya; Pinkham, Ashley

    2014-01-01

    This article make a case for the importance of background knowledge in children's comprehension. It suggests that differences in background knowledge may account for differences in understanding text for low- and middle-income children. It then describes strategies for building background knowledge in the age of common core standards.

  11. Noise sustained propagation: Local versus global noise

    OpenAIRE

    Locher, M.; Chatterjee, N.; Marchesoni, F.; Ditto, W. L.; Hunt, E. R.

    2000-01-01

    We expand on prior results on noise supported signal propagation in arrays of coupled bistable elements. We present and compare experimental and numerical results for kink propagation under the influence of local and global fluctuations. As demonstrated previously for local noise, an optimum range of global noise power exists for which the medium acts as a reliable transmission ``channel''. We discuss implications for propagation failure in a model of cardiac tissue and present a general theo...

  12. Noise reduction of dental drill noise

    OpenAIRE

    Rotter, KRGR; Atherton, MA; Kaymak, E; Millar, BJ

    2008-01-01

    Dental drills produce a characteristic noise that is uncomfortable for patients and is also known to be harmful to dentists under prolonged exposure. It is therefore desirable to protect the patient and dentist whilst allowing two-way communication, which will require a headphone - type system. Re-establishing good communication between the dentist and patient will be achieved through a combination of three noise cancellation technologies, namely, Passive Noise Control (PNC), Adaptive Filteri...

  13. Active noise cancellation algorithms for impulsive noise

    OpenAIRE

    Li, Peng; Yu, Xun

    2012-01-01

    Impulsive noise is an important challenge for the practical implementation of active noise control (ANC) systems. The advantages and disadvantages of popular filtered-X least mean square (FXLMS) ANC algorithm and nonlinear filtered-X least mean M-estimate (FXLMM) algorithm are discussed in this paper. A new modified FXLMM algorithm is also proposed to achieve better performance in controlling impulsive noise. Computer simulations and experiments are carried out for all three algorithms and th...

  14. Gravitational wave background from binary systems

    CERN Document Server

    Rosado, Pablo A

    2011-01-01

    Basic aspects of the background of gravitational waves and its mathematical characterization are reviewed. The spectral energy density parameter $\\Omega(f)$, commonly used as a quantifier of the background, is derived for an ensemble of many identical sources emitting at different times and locations. For such an ensemble, $\\Omega(f)$ is generalized to account for the duration of the signals and of the observation, so that one can distinguish the resolvable and unresolvable parts of the background. The unresolvable part, often called confusion noise or stochastic background, is made by signals that cannot be either individually identified or subtracted out of the data. To account for the resolvability of the background, the overlap function is introduced. This function is a generalization of the duty cycle, which has been commonly used in the literature, in some cases leading to incorrect results. The spectra produced by binary systems (stellar binaries and massive black hole binaries) are presented over the ...

  15. Noise characteristics of CT perfusion imaging: how does noise propagate from source images to final perfusion maps?

    Science.gov (United States)

    Li, Ke; Chen, Guang-Hong

    2016-03-01

    Cerebral CT perfusion (CTP) imaging is playing an important role in the diagnosis and treatment of acute ischemic strokes. Meanwhile, the reliability of CTP-based ischemic lesion detection has been challenged due to the noisy appearance and low signal-to-noise ratio of CTP maps. To reduce noise and improve image quality, a rigorous study on the noise transfer properties of CTP systems is highly desirable to provide the needed scientific guidance. This paper concerns how noise in the CTP source images propagates to the final CTP maps. Both theoretical deviations and subsequent validation experiments demonstrated that, the noise level of background frames plays a dominant role in the noise of the cerebral blood volume (CBV) maps. This is in direct contradiction with the general belief that noise of non-background image frames is of greater importance in CTP imaging. The study found that when radiation doses delivered to the background frames and to all non-background frames are equal, lowest noise variance is achieved in the final CBV maps. This novel equality condition provides a practical means to optimize radiation dose delivery in CTP data acquisition: radiation exposures should be modulated between background frames and non-background frames so that the above equality condition is satisïnAed. For several typical CTP acquisition protocols, numerical simulations and in vivo canine experiment demonstrated that noise of CBV can be effectively reduced using the proposed exposure modulation method.

  16. Directional monitoring terminal for aircraft noise

    Science.gov (United States)

    Genescà, M.

    2016-07-01

    This paper presents a concept of an aircraft noise monitoring terminal (NMT) that reduces background noise and the influence of ground reflection, in comparison with a single microphone. Also, it automatically identifies aircraft sound events based on the direction of arrival of the sound rather than on the sound pressure level (or radar data). And moreover, it provides an indicator of the quality of the sound pressure level measurement, i.e. if it is possibly disturbed by extraneous sources. The performance of this NMT is experimentally tested under real conditions in a measurement site close to Zurich airport. The results show that the NMT unambiguously identifies the noise events generated by the target aircraft, correctly detects those aircraft noise events that may be disturbed by the presence of other sources, and offers a substantial reduction in background and ground reflected sound.

  17. 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

  18. Predicting Anthropogenic Noise Contributions to US Waters.

    Science.gov (United States)

    Gedamke, Jason; Ferguson, Megan; Harrison, Jolie; Hatch, Leila; Henderson, Laurel; Porter, Michael B; Southall, Brandon L; Van Parijs, Sofie

    2016-01-01

    To increase understanding of the potential effects of chronic underwater noise in US waters, the National Oceanic and Atmospheric Administration (NOAA) organized two working groups in 2011, collectively called "CetSound," to develop tools to map the density and distribution of cetaceans (CetMap) and predict the contribution of human activities to underwater noise (SoundMap). The SoundMap effort utilized data on density, distribution, acoustic signatures of dominant noise sources, and environmental descriptors to map estimated temporal, spatial, and spectral contributions to background noise. These predicted soundscapes are an initial step toward assessing chronic anthropogenic noise impacts on the ocean's varied acoustic habitats and the animals utilizing them. PMID:26610977

  19. Noise in distributed erbium-doped fibers

    DEFF Research Database (Denmark)

    Rottwitt, Karsten; Povlsen, Jørn Hedegaard; Bjarklev, Anders Overgaard;

    1993-01-01

    Theoretical limits in noise figure for a long-haul transmission line based on lumped amplification are contrasted with distributed amplification. The latter results in a reduction of approximately 60% of the required number of pump power stations. The distributed optical amplification is provided...... by an erbium-doped fiber and comparisons of aluminum and germanium as codopant materials are shown. The pump power consumption and noise figure are analyzed with respect to the background loss...

  20. Amperometric Noise at Thin Film Band Electrodes

    DEFF Research Database (Denmark)

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

    2012-01-01

    Background current noise is often a significant limitation when using constant-potential amperometry for biosensor application such as amperometric recordings of transmitter release from single cells through exocytosis. In this paper, we fabricated thin-film electrodes of gold and conductive...... presented here can be used for choosing an electrode material and dimensions and when designing chip-based devices for low-noise current measurements....

  1. Whitening of Background Brain Activity via Parametric Modeling

    Directory of Open Access Journals (Sweden)

    Nidal Kamel

    2007-01-01

    Full Text Available Several signal subspace techniques have been recently suggested for the extraction of the visual evoked potential signals from brain background colored noise. The majority of these techniques assume the background noise as white, and for colored noise, it is suggested to be whitened, without further elaboration on how this might be done. In this paper, we investigate the whitening capabilities of two parametric techniques: a direct one based on Levinson solution of Yule-Walker equations, called AR Yule-Walker, and an indirect one based on the least-squares solution of forward-backward linear prediction (FBLP equations, called AR-FBLP. The whitening effect of the two algorithms is investigated with real background electroencephalogram (EEG colored noise and compared in time and frequency domains.

  2. NASA propeller noise research

    Science.gov (United States)

    Greene, G. C.

    1980-01-01

    The research in propeller noise prediction, noise/performance optimization, and interior reduction is described. Selected results are presented to illustrate the status of the technology and the direction of future research.

  3. Yesterday's noise - today's signal

    International Nuclear Information System (INIS)

    Noise signals can yield information on both the dynamic and steady-state performance of a system. Application of signal noise presents many challenges which can be met successfully, resulting in significant benefits. The concept and characteristics of signal noise and the benefits that can be obtained through use of signal noise are discussed. Results from practical applications to nuclear systems are given with emphasis on applications to the Gentilly-1 reactor

  4. Filtering Solid Gabor Noise

    OpenAIRE

    Lagae, Ares; Drettakis, George

    2011-01-01

    Solid noise is a fundamental tool in computer graphics. Surprisingly, no existing noise function supports both high-quality anti-aliasing and continuity across sharp edges. In this paper we show that a slicing approach is required to preserve continuity across sharp edges, and we present a new noise function that supports anisotropic filtering of sliced solid noise. This is made possible by individually filtering the slices of Gabor kernels, which requires the proper treatment of phase. This ...

  5. Coupling Reduces Noise

    OpenAIRE

    Kia, Behnam; Kia, Sarvenaz; Lindner, John. F.; Sinha, Sudeshna; Ditto, William L.

    2014-01-01

    We demonstrate how coupling nonlinear dynamical systems can reduce the effects of noise. For simplicity we investigate noisy coupled map lattices. Noise from different lattice nodes can diffuse across the lattice and lower the noise level of individual nodes. We develop a theoretical model that explains this observed noise evolution and show how the coupled dynamics can naturally function as an averaging filter. Our numerical simulations are in excellent agreement with the model predictions.

  6. Nonlinear noise cancellation

    OpenAIRE

    Strauch, Paul E

    1997-01-01

    Noise or interference is often assumed to be a random process. Conventional linear filtering, control or prediction techniques are used to cancel or reduce the noise. However, some noise processes have been shown to be nonlinear and deterministic. These nonlinear deterministic noise processes appear to be random when analysed with second order statistics. As nonlinear processes are widespread in nature it may be beneficial to exploit the coherence of the nonlinear deterministic no...

  7. Noise in electromigrated nanojunctions

    OpenAIRE

    Wheeler, P. J.; Chen, Ruoyu; Natelson, D.

    2013-01-01

    Noise measurements are a probe beyond simple electronic transport that can reveal additional information about electronic correlations and inelastic processes. Here we report noise measurements in individual electromigrated nanojunctions, examining the evolution from the many channel regime to the tunneling regime, using a radio frequency technique. While we generally observe the dependence of noise on bias expected for shot noise, in approximately 12% of junction configurations we find discr...

  8. Noise and Neuronal Heterogeneity

    OpenAIRE

    Barber, Michael J.; Ristig, Manfred L.

    2010-01-01

    We consider signal transaction in a simple neuronal model featuring intrinsic noise. The presence of noise limits the precision of neural responses and impacts the quality of neural signal transduction. We assess the signal transduction quality in relation to the level of noise, and show it to be maximized by a non-zero level of noise, analogous to the stochastic resonance effect. The quality enhancement occurs for a finite range of stimuli to a single neuron; we show how to construct network...

  9. Noise in mesoscopic physics

    OpenAIRE

    Martin, Thierry

    2005-01-01

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

  10. The Cosmic Microwave Background

    OpenAIRE

    Silk, Joseph

    2001-01-01

    This set of lectures provides an overview of the basic theory and phenomenology of the cosmic microwave background. Topics include a brief historical review; the physics of temperature and polarization fluctuations; acoustic oscillations of the primordial plasma; the space of inflationary cosmological models; current and potential constraints on these models from the microwave background; and constraints on inflation.

  11. Characteristics of USB noise

    Science.gov (United States)

    Gibson, J. S.; Searle, N.

    1976-01-01

    An extensive series of noise measurements, for a variety of geometric and operational parameters, was made on models of upper surface blowing (USB) powered lift systems. The data obtained were analyzed and the effects and trends of parametric variation defined. The behavior and nature of USB noise and the design of USB systems with low noise characteristics is examined.

  12. 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...

  13. Signs of noise-induced neural degeneration in humans

    DEFF Research Database (Denmark)

    Holtegaard, Pernille; Olsen, Steen Østergaard

    2015-01-01

    background noise, while leaving the processing of low-level stimuli unaffected. The purpose of this study was to investigate if signs of such primary neural damage from noise-exposure could also be found in noiseexposed human individuals. It was investigated: (1) if noise-exposed listeners with hearing...... thresholds within the “normal” range perform poorer, in terms of their speech recognition threshold in noise (SRTN), and (2) if auditory brainstem responses (ABR) reveal lower amplitude of wave I in the noise-exposed listeners. A test group of noise/music-exposed individuals and a control group were...... recruited. All subjects were between 18-32 years of age and had pure-tone thresholds ≤ 15 dB HL from 250-8000 Hz. Despite normal pure-tone thresholds, the noise-exposed listeners required a significantly better signal-to-noise ratio to obtain SRTN, compared to the control group. The ABR results showed...

  14. 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

  15. Classical noise, quantum noise and secure communication

    Science.gov (United States)

    Tannous, C.; Langlois, J.

    2016-01-01

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

  16. Adaptive Noise Reduction System

    Directory of Open Access Journals (Sweden)

    Ivana Ropuš

    2013-01-01

    Full Text Available Noise is an all-present environment pollutant, considered to be one of the greatest contemporary pollutants. World-wide, co-ordinated actions are conducted in order to develop systems which minimise the noise influence onto society.In this article we argue that novel approach to suppression of influence of noise is useful. Furthermore, we argue that the efficient approach is formulation of the efficient, broadly applicable, ubiquituous, adaptive noise-protection system. The approach combines the natural noise-protection form based on plants with the artificially formed coatings.Elements of the system are discussed, its formation and maintenance analysed and perspectives conjectured.

  17. Low-noise amplifier

    OpenAIRE

    V. B. Gulkov; A. S. Makarenko

    2012-01-01

    The mixture of signal and noise processing device is considered in this article. It contains two channels: the main channel (MC) contains the mixture of signal and noise, and compensation channel (CC) that extracts just a noise from the mixture. The feature of the processing circuit is that the mixture samples are formed by short impulses at the moments of passing signal through zero. Further antiphase noise is set in the channels, adder by which the noise is removed from mixture is set on th...

  18. 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....

  19. Low-noise amplifier

    Directory of Open Access Journals (Sweden)

    V. B. Gulkov

    2012-11-01

    Full Text Available The mixture of signal and noise processing device is considered in this article. It contains two channels: the main channel (MC contains the mixture of signal and noise, and compensation channel (CC that extracts just a noise from the mixture. The feature of the processing circuit is that the mixture samples are formed by short impulses at the moments of passing signal through zero. Further antiphase noise is set in the channels, adder by which the noise is removed from mixture is set on the cannels output. Study of the described device was carried out for simulated AM signal and white Gaussian noise in simulation environment Matlab. The results are shown, that device reduces noise by 16 dB of power.

  20. Active3 noise reduction

    International Nuclear Information System (INIS)

    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

  1. Cosmogenic Backgrounds to 0{\

    CERN Document Server

    :,; Auty, D J; Barbeau, P S; Beck, D; Belov, V; Breidenbach, M; Brunner, T; Burenkov, A; Cao, G F; Chambers, C; Cleveland, B; Coon, M; Craycraft, A; Daniels, T; Danilov, M; Daugherty, S J; Davis, J; Delaquis, S; Der Mesrobian-Kabakian, A; DeVoe, R; Didberidze, T; Dilling, J; Dolgolenko, A; Dolinski, M J; Dunford, M; Fairbank, W; Farine, J; Feldmeier, W; Feyzbakhsh, S; Fierlinger, P; Fudenberg, D; Gornea, R; Graham, K; Gratta, G; Hall, C; Herrin, S; Hughes, M; Jewell, M J; Johnson, A; Johnson, T N; Johnston, S; Karelin, A; Kaufman, L J; Killick, R; Koffas, T; Kravitz, S; Krücken, R; Kuchenkov, A; Kumar, K S; Leonard, D S; Licciardi, C; Lin, Y H; Ling, J; MacLellan, R; Marino, M G; Mong, B; Moore, D; Njoya, O; Nelson, R; Odian, A; Ostrovskiy, I; Piepke, A; Pocar, A; Prescott, C Y; Retière, F; Rowson, P C; Russell, J J; Schubert, A; Sinclair, D; Smith, E; Stekhanov, V; Tarka, M; Tolba, T; Tsang, R; Twelker, K; Vuilleumier, J -L; Waite, A; Walton, J; Walton, T; Weber, M; Wen, L J; Wichoski, U; Wood, J; Yang, L; Yen, Y -R; Zeldovich, O Ya

    2015-01-01

    As neutrinoless double-beta decay experiments become more sensitive and intrinsic radioactivity in detector materials is reduced, previously minor contributions to the background must be understood and eliminated. With this in mind, cosmogenic backgrounds have been studied with the EXO-200 experiment. Using the EXO-200 TPC, the muon flux (through a flat horizontal surface) underground at the Waste Isolation Pilot Plant (WIPP) has been measured to be {\\Phi} = 4.07 $\\pm$ 0.14 (sys) $\\pm$ 0.03 (stat) $\\times$ $10^{-7}$cm$^{-2}$ s$^{-1}$, with a vertical intensity of $I_{v}$ = 2.97$^{+0.14}_{-0.13}$ (sys) $\\pm$ 0.02 (stat) $\\times$ $10^{-7}$cm$^{-2}$ s$^{-1}$ sr$^{-1}$. Simulations of muon-induced backgrounds identified several potential cosmogenic radionuclides, though only 137Xe is a significant background for the 136Xe 0{\

  2. Nuclear Spin Noise and STM Noise Spectroscopy

    OpenAIRE

    Balatsky, A. V.; Fransson, J.; Mozyrsky, D.; Manassen, Yishay

    2006-01-01

    We consider fluctuations of the electronic spin due to coupling to nuclear spin. Noise spectroscopy of an electronic spin can be revealed in the Scanning Tunnelling Microscope (STM). We argue that the noise spectroscopy of electronic spin can reveal the nuclear spin dynamics due to hyperfine coupling. Tunnelling current develops satellites of the main lines at Larmor frequency and at zero frequency due to hyperfine coupling. We also address the role of the rf field that is at or near the reso...

  3. On Background Independence

    OpenAIRE

    Anderson, Edward

    2013-01-01

    This paper concerns what Background Independence itself is (as opposed to some particular physical theory that is background independent). The notions presented mostly arose from a layer-by-layer analysis of the facets of the Problem of Time in Quantum Gravity. Part of this coincides with two relational postulates which are thus identified as classical precursors of two of the facets of the Problem of Time. These are furthemore tied to the forms of each of the GR Hamiltonian and momentum cons...

  4. Zambia Country Background Report

    DEFF Research Database (Denmark)

    Hampwaye, Godfrey; Jeppesen, Søren; Kragelund, Peter

    This paper provides background data and general information for the Zambia studies focusing on local food processing sub­‐sector; and the local suppliers to the mines as part of the SAFIC project (Successful African Firms and Institutional Change).......This paper provides background data and general information for the Zambia studies focusing on local food processing sub­‐sector; and the local suppliers to the mines as part of the SAFIC project (Successful African Firms and Institutional Change)....

  5. 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.

  6. The influences of low frequency noise on mental performance

    Directory of Open Access Journals (Sweden)

    J. Hatami

    2008-01-01

    Full Text Available AbstractBackground and Purpose: Although the evolution of industrial systems toward digital technologies decreased the exposure to high levels of noise, it has created some problems encountered with low level and provoking noise (low frequency noise. In the present work, the mental performance of students exposed to low frequency and reference noises at low and high levels (45 & 65 dB were studied. Additionally, other factors such as annoyance, sensitivity to low frequency noise and hearing status of participants were considered.Materials and Methods: After generating low frequency and reference noises required for the study, a pilot study was conducted. Then, 54 students participated in the main study after preliminary tests. Their mental performances were evaluated with standard psychological tests while they were exposed to low frequency and reference noises at 45 and 65 dBA.Results: The results showed that noise annoyance and low frequency noise sensitivity do not have a significant correlation with age and sex. The results also revealed that, low frequency noise at 65 dB can decrease concentration (P=0.003 and increase response time (P=0.039 of performance in comparison with low frequency noise at 45 dB. On the other hand, reference noise at 65 dB can increase speed (P<0.001 of performance in comparison with reference noise at 45 dB.Conclusion: Low frequency noise can reduce the mental performance and increase its response time.Key words: Low Frequency Noise, Reference Noise, Noise Annoyance, Mental PerformanceJ Mazand Univ Med Sci 2008; 18(63: 55-65(Persian

  7. Dip listening or modulation masking? Call recognition by green treefrogs (Hyla cinerea) in temporally fluctuating noise

    OpenAIRE

    Vélez, Alejandro; Höbel, Gerlinde; Gordon, Noah M.; Bee, Mark A.

    2012-01-01

    Despite the importance of perceptually separating signals from background noise, we still know little about how nonhuman animals solve this problem. Dip listening, an ability to catch meaningful ‘acoustic glimpses’ of a target signal when fluctuating background noise levels momentarily drop, constitutes one possible solution. Amplitude-modulated noises, however, can sometimes impair signal recognition through a process known as modulation masking. We asked whether fluctuating noise simulating...

  8. X-ray background measurements with XMM-Newton EPIC

    OpenAIRE

    Lumb, D. H.; Warwick, R. S.; Page, M.; De Luca, A.

    2002-01-01

    We discuss the methods used to compile a high signal-to-noise dataset representative of both the instrumental and cosmic background signal measured at high galactic latitude by the XMM-Newton EPIC cameras. The characteristics of the EPIC background are described and the potential applications of the derived dataset in general science analysis are outlined. In the case of the cosmic X-ray background, the transition between a hard power-law spectrum (due to the integrated emission of unresolved...

  9. Road Traffic Noise - A study of region Skåne, Sweden

    OpenAIRE

    Farcas, Florentina

    2008-01-01

    Since the first car appeared, the pollution on the roads became an issue, which is still mainly unsolved. Too many people complain about traffic noise. Various methods have been developed that aimed at minimizing the noise pollution and improving the environment. This thesis presents the problems posed by noise pollution, covers the background of noise pollution and its effects on human health. Another important part of the thesis covers the method of noise calculation which applies in specif...

  10. Determination of background radiation

    International Nuclear Information System (INIS)

    The invention relates to a method and appartus for determining the level of background radiation in a spectral region where a Raman peak characteristic of a particular substance, in particular diamond, is expected to occur. The method includes the steps of isolating the radiation in a first spectral band, and isolating the radiation in a second spectral band which overlaps the first spectral band at least partially to form an overlapping band in the vicinity of the expected Raman Peak and a least one sideband. At least one sideband value representative of the radiation present in the one or more sidebands is then obtained, and further values, representative of the radiation isolated by any one or more of the other spectral bands, such as the first and second bands, are then used to derive a background value indicative of the level of background radiation present at the position of the expected Raman peak

  11. Exploring String Theory Backgrounds

    CERN Document Server

    Williams, B P

    2004-01-01

    This thesis examines phenomenological and theoretical questions by exploring string theoretic backgrounds. Part I focuses on cosmology. First we propose that the induced metric along a brane moving through a curved bulk may be interpreted as the cosmology of the brane universe, providing a resolution to the apparent cosmological singularity on the brane. We then look at various decay channels of the certain meta-stable de Sitter vacua and show that there exist NS5-brane meditated decays which are much faster than decays to decompactification. Part II discusses a new class of nongeometric vacua in string theory. These backgrounds may be described locally as T2 fibrations. By enlarging the monodromy group of the fiber to include perturbative stringy duality symmetries we are able to explicitly construct nongeometric backgrounds.

  12. Unitarity and singular backgrounds

    CERN Document Server

    Brouzakis, Nikos

    2013-01-01

    We compute the graviton Kaluza-Klein spectrum on a gravity-dilaton background with a naked singularity for all possible boundary conditions at the singularity which are consistent with unitary evolution. We apply methods from non-relativistic quantum mechanics with singular Schr\\"{o}dinger potentials. In general the spectrum contains a tachyon, a sign of instability. Only for a particular boundary condition at the singularity the spectrum is free of tachyons. In this case the lowest-lying graviton mode is massless. We argue that this result will also hold for other backgrounds with similar geometry near the curvature singularity. We complete our study with a brief discussion on radion perturbations and Higgs mechanism on this singular background.

  13. Noise control of radiological monitoring equipment

    International Nuclear Information System (INIS)

    Although vacuum pumps on continuous air monitors (CAMs) do not produce noise levels above regulatory limits, engineering controls were used to establish a safer work environment. Operations performed in areas where CAMs are located are highly specialized and require precision work when handling nuclear materials, heavy metals, and inert gases. Traditional methods for controlling noise such as enclosing or isolating the source and the use of personal protection equipment were evaluated. An innovative solution was found by retrofitting CAMs with air powered multistage ejectors pumps. By allowing the air to expand in several chambers to create a vacuum, one can eliminate the noise hazard altogether. In facilities with adequate pressurized air, use of these improved ejector pumps may be a cost-effective replacement for noisy vacuum pumps. A workplace designed or engineered with noise levels as low as possible or as close to background adds to increased concentration, attention to detail, and increased production

  14. Aerodynamical noise from wind turbine generators

    International Nuclear Information System (INIS)

    Two extensive measurement series of noise from wind turbines have been made during different modifications of their rotors. One series focused on the influence from the tip shape on the noise, while the other series dealt with the influence from the trailing edge. The experimental layout for the two investigations was identical. The total A-weighted noise from the wind turbine was measured in 1/3 octave bands from 50 Hz to 10 kHz in 1-minute periods simultaneously with wind speed measurements. The microphone was mounted on a hard board on the ground about 40 m directly downwind of the wind turbine, and the wind speed meter was placed at the same distance upwind of the wind turbine 10 m above ground. Regression analysis was made between noise and wind speed in each 1/3 octave band to determine the spectrum at 8 m/s. During the measurements care was taken to avoid influence from background noise, and the influence from machinery noise was minimized and corrected for. Thus the results display the aerodynamic rotor noise from the wind turbines. By use of this measurement technique, the uncertainty has been reduced to 1.5 - 2 dB per 1/3 octave band in the relevant frequency range and to about 1 dB on the total A-weighted levels. (au) (10 refs.)

  15. Ambient noise levels in the Taiwan region

    Science.gov (United States)

    Liang, W.; Liu, C.; Chen, R.; Huang, B.; Wu, F. T.; Wang, C.

    2008-12-01

    To characterize the island-wide background seismic noise in Taiwan, we estimate the power spectral density (PSD) at broadband stations of both the BATS (Broadband Array in Taiwan for Seismology) and the TAIGER experiment (Apr. 2006~Apr. 2008) for periods ranging from ~0.2 to 100 seconds. A new approach to calculate the probability density functions of noise power (PDFs, MaNamara and Buland, 2004) is used in this study. The results indicate that the cultural noise at higher frequencies is significant at populated area, which shows diurnal and weekly variation as what we expected. The noise power for microseisms centered at a period of ~5 seconds around the western costal plain show ~20dB higher than what observed at eastern Taiwan. This observation supports the inference that the coastal regions having narrow shelf with irregular coastlines are know to be especially efficient at radiating the predominat microseisms. Results from the linear array across central Taiwan demonstrate that the average noise power is quietest at the eastern Central Range. We have mapped the PDF mode for stations at various periods to see the spatial distribution of ambient noise levels, which could be used as the basic information for future station siting. Temporal variation of noise PSD is also present to provide a quantitative description of the seismic data quality collected by both BATS and TAIGER experiment. Some operational problems like base tilt, sensitivity change can be identified easily as well.

  16. Noise impact assessment of wind farms

    International Nuclear Information System (INIS)

    The noise impact assessment of a wind farm is dependent upon a number of factors pertinent to the site. The most controversial is the selection of a criterion which is acceptable to both the developer of a site, in terms of maximising the number of turbines he may operate without fear of injunction to stop, and the local residents and Environmental Health Officer who will have to enforce any agreements. A number of British Standards exist which cover noise issues. There are, however, certain reservations about their use when applied to potential wind farm developments; some of the more relevant standards are outlined. In addition, Draft Planning Guidance notes which have recently been issued are discussed. These are intended to provide an indication to local planning authorities as to what noise levels and criteria may be acceptable when considering noise emitted by wind farms. No European standard for noise emission from wind farms exists but the legislative position in Denmark, the Netherlands, Germany and Sweden is briefly considered. It is considered that when a maximum level criterion is set it should take into account the existing background noise levels based on measurements which are taken at the most sensitive dwellings to the site. A method for calculating emitted noise levels from turbine arrays is described. (UK)

  17. Timing Noise Analysis of NANOGrav Pulsars

    CERN Document Server

    Perrodin, Delphine; Lommen, Andrea; Finn, Lee; Demorest, Paul; Ferdman, Robert; Gonzalez, Marjorie; Nice, David; Ransom, Scott; Stairs, Ingrid

    2013-01-01

    We analyze timing noise from five years of Arecibo and Green Bank observations of the seventeen millisecond pulsars of the North-American Nanohertz Observatory for Gravitational Waves (NANOGrav) pulsar timing array. The weighted autocovariance of the timing residuals was computed for each pulsar and compared against two possible models for the underlying noise process. The first model includes red noise and predicts the autocovariance to be a decaying exponential as a function of time lag. The second model is Gaussian white noise whose autocovariance would be a delta function. We also perform a ``nearest-neighbor" correlation analysis. We find that the exponential process does not accurately describe the data. Two pulsars, J1643-1224 and J1910+1256, exhibit weak red noise, but the rest are well described as white noise. The overall lack of evidence for red noise implies that sensitivity to a (red) gravitational wave background signal is limited by statistical rather than systematic uncertainty. In all pulsars...

  18. Assessment of NASA's Aircraft Noise Prediction Capability

    Science.gov (United States)

    Dahl, Milo D. (Editor)

    2012-01-01

    A goal of NASA s Fundamental Aeronautics Program is the improvement of aircraft noise prediction. This document provides an assessment, conducted from 2006 to 2009, on the current state of the art for aircraft noise prediction by carefully analyzing the results from prediction tools and from the experimental databases to determine errors and uncertainties and compare results to validate the predictions. The error analysis is included for both the predictions and the experimental data and helps identify where improvements are required. This study is restricted to prediction methods and databases developed or sponsored by NASA, although in many cases they represent the current state of the art for industry. The present document begins with an introduction giving a general background for and a discussion on the process of this assessment followed by eight chapters covering topics at both the system and the component levels. The topic areas, each with multiple contributors, are aircraft system noise, engine system noise, airframe noise, fan noise, liner physics, duct acoustics, jet noise, and propulsion airframe aeroacoustics.

  19. Microscopic traffic modelling in urban noise assessment

    Science.gov (United States)

    de Coensel, Bert; Botteldooren, Dick; de Muer, Tom; Peeters, Bert; van Blokland, Gijsjan

    2005-04-01

    The temporal structure of the urban soundscape can be rather complex, due to the presence of many screening and reflecting surfaces and many different sound sources, of which traffic noise is the most dominant. From the point of view of soundscape research, the background level as well as the time structure of noise peaks are important. However, these indicators cannot be estimated easily by current noise prediction models, based on static traffic flows. Therefore, a dynamic traffic noise model was used, based on a microscopic traffic simulation. This way, individual vehicles can be traced, each having an associated set of noise sources that can depend on vehicle properties such as speed and acceleration, as well as on road properties such as the surface type. The model further consists of an ISO 9613 based propagation component, which can account for multiple reflections and diffractions. Maps of statistical noise levels, but also of more complicated measures reflecting the time structure of the soundscape, can be produced. This way, the soundscape contribution of single vehicles can be traced, as well as the influence of more general vehicle properties, such as the contribution of vehicle acceleration noise to the soundscape at junctions.

  20. Cosmic Tachyon Background Radiation

    CERN Document Server

    Tomaschitz, R

    1999-01-01

    The equilibrium statistical mechanics of a background radiation of superluminal particles is investigated, based on a vectorial wave equation for tachyons of the Proca type. The partition function, the spectral energy density, and the various thermodynamic variables of an ideal Bose gas of tachyons in an open Robertson-Walker cosmology are derived. The negative mass square in the wave equation changes the frequency scaling in the Rayleigh-Jeans law, and there are also significant changes in the low temperature regime as compared to the microwave background, in particular in the caloric and thermal equations of state.

  1. The natural radiation background

    International Nuclear Information System (INIS)

    The components of the natural background radiation and their variations are described. Cosmic radiation is a major contributor to the external dose to the human body whilst naturally-occurring radionuclides of primordial and cosmogenic origin contribute to both the external and internal doses, with the primordial radionuclides being the major contributor in both cases. Man has continually modified the radiation dose to which he has been subjected. The two traditional methods of measuring background radiation, ionisation chamber measurements and scintillation counting, are looked at and the prospect of using thermoluminescent dosimetry is considered

  2. Johnson Noise Thermometry System Requirements

    Energy Technology Data Exchange (ETDEWEB)

    Britton Jr, Charles L [ORNL; Roberts, Michael [ORNL; Ezell, N Dianne Bull [ORNL; Qualls, A L [ORNL; Holcomb, David Eugene [ORNL

    2013-01-01

    This document is intended to capture the requirements for the architecture of the developmental electronics for the ORNL-lead drift-free Johnson Noise Thermometry (JNT) project conducted under the Instrumentation, Controls, and Human-Machine Interface (ICHMI) research pathway of the U.S. Department of Energy (DOE) Advanced Small Modular Reactor (SMR) Research and Development (R&D) program. The requirements include not only the performance of the system but also the allowable measurement environment of the probe and the allowable physical environment of the associated electronics. A more extensive project background including the project rationale is available in the initial project report [1].

  3. Objective and subjective rating of tonal noise radiated from UK wind farms

    International Nuclear Information System (INIS)

    The radiation of noise to the environment is currently a major issue with regard to U.K. wind farm developments. The reason for this concern is not that wind turbines are unduly noisy, but rather because wind farms are often located in rural areas where background noise levels can fall very low. The fact that background noise levels fall so low in these areas means that the permissible noise radiation from wind farms must also be kept similarly low if nuisance to local residents is to be avoided. However, ensuring that the overall noise level of the wind farm does not exceed the pre-existing background noise level by more than a set amount is not the whole story. Noise radiated from wind turbines can exhibit characteristics that set it apart from the natural background noises typically found in quiet rural areas, where ''natural'' background noises might include the sound of the wind blowing through trees, or the sound of running water. One of the acoustic characteristics that can be attributed to some wind turbines is the radiation of tonal noise from mechanical plant located in the nacelles. It is well accepted that tonal components in otherwise broad band, or ''characterless'', noise, can increase the subjective perception of that noise. Account for increased annoyance due to tones is found in both of the British Standards which relate to environmental noise; BS4142 and BS7445. (UK)

  4. Mitigation of calorimeter noise.

    Energy Technology Data Exchange (ETDEWEB)

    Santi, P. A. (Peter A.); Bracken, D. S. (David S.); Smith, M. K. (Morag K.)

    2004-01-01

    One of the main factors that limit the sensitivity of calorimeters is the noise in the calorimeter response. A previous study into the sources of noise in a Wheatstone bridge calorimeter used by Department of Energy (DOE) facilities has shown that the control system for maintaining the water bath at a constant temperature was an important contributor to the noise in the system. In order to minimize the contribution that the control system makes to the noise in the calorimeter response, a new control system for the calorimeter has been developed. An experimental and analytical study has been performed to determine the effectiveness of this new control system in reducing the response noise in a Wheatstone bridge calorimeter. The results of this study are presented along with their implications for future work in minimizing the equilibrium noise of calorimeters.

  5. Adaptive noise cancellation

    International Nuclear Information System (INIS)

    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)

  6. Thoughts out of noise

    International Nuclear Information System (INIS)

    We study the effects of additive Gaussian noise on the behaviour of a simple spatially extended system, which is locally modelled by a nonlinear two-dimensional iterated map describing neuronal dynamics. In particular, we focus on the ability of noise to induce spatially ordered patterns, i.e. the so-called noise-induced pattern formation. For intermediate noise intensities, the spatially extended system exhibits ordered circular waves, thereby clearly manifesting the constructive role of random perturbations. The emergence of observed noise-induced patterns is explained with simple arguments that are obtained by analysing the typical spatial scale of patterns evoked by various diffusion coefficients. Since discrete-time systems are straightforward to implement and require modest computational capabilities, the present study describes one of the most fascinating and visually compelling examples of noise-induced self-organization in nonlinear systems in an accessible way for graduate or even advanced undergraduate students attending a nonlinear dynamics course

  7. Efficient Data Averaging for Spin Noise Spectroscopy in Semiconductors

    CERN Document Server

    Müller, Georg M; Hübner, Jens; Oestreich, Michael

    2010-01-01

    Spin noise spectroscopy (SNS) is the perfect tool to investigate electron spin dynamics in semiconductors at thermal equilibrium. We simulate SNS measurements and show that ultrafast digitizers with low bit depth enable sensitive, high bandwidth SNS in the presence of strong optical background shot noise. The simulations reveal that optimized input load at the digitizer is crucial for efficient spin noise detection while the bit depth influences the sensitivity rather weakly.

  8. Cardiovascular effects of environmental noise: Research in Germany

    OpenAIRE

    Christian Maschke

    2011-01-01

    Research on systematic noise effects started in Germany back in the fifties with basic experimental studies on humans. As a result, noise was classified as a non-specific stressor, which could cause an ergotropic activation of the complete organism. In the light of this background research a hypothesis was proposed that long-term noise exposure could have an adverse effect on health. This hypothesis was further supported by animal studies. Since the sixties, the adverse effects of chronic roa...

  9. Reliability, synchrony and noise

    OpenAIRE

    Ermentrout, G. Bard; Galán, Roberto F; Urban, Nathaniel N.

    2008-01-01

    The brain is noisy. Neurons receive tens of thousands of highly fluctuating inputs and generate spike trains that appear highly irregular. Much of this activity is spontaneous—uncoupled to overt stimuli or motor outputs—leading to questions about the functional impact of this noise. Although noise is most often thought of as disrupting patterned activity and interfering with the encoding of stimuli, recent theoretical and experimental work has shown that noise can play a constructive role—lea...

  10. Word Identification in Noise

    OpenAIRE

    Pisoni, David B.

    1996-01-01

    Speech intelligibility has traditionally been measured by presenting words mixed in noise to listeners for identification at several different signal-to-noise ratios. The words are produced in isolation or in sentence contexts where the predictability of specific items can be varied. Psychometric functions are typically obtained relating signal-to-noise ratio to percent correct recognition. Error analyses are often carried out by examining response confusions to construct similarity spaces fo...

  11. Multidimensional Speckle Noise Model

    OpenAIRE

    Fàbregas Xavier; López-Martínez Carlos; Pottier Eric

    2005-01-01

    One of the main problems of SAR imagery is the presence of speckle noise, originated by the inherent coherent nature of this type of systems. For one-dimensional SAR systems it has been demonstrated that speckle can be considered as a multiplicative noise term. Nevertheless, this simple model cannot be exported when multidimensional SAR imagery is addressed. This paper is devoted to present the latest advances into the definition of a multidimensional speckle noise model which does not depen...

  12. Nuclear spin noise imaging

    OpenAIRE

    Müller, Norbert; Jerschow, Alexej

    2006-01-01

    NMR images were obtained from the proton spin noise signals of a water-containing phantom, which was placed in the highly tuned, low-noise resonant circuit of a cryogenically cooled NMR probe in the presence of systematically varied magnetic field gradients. The spatially resolved proton spin density was obtained from the raw signal by a modified projection–reconstruction protocol. Although spin noise imaging is inherently less sensitive than conventional magnetic resonance imaging, it afford...

  13. Aircrafts' taxi noise emission

    OpenAIRE

    Asensio Rivera, César; Pagán Muñoz, Raúl; López Navarro, Juan Manuel

    2008-01-01

    During planning stages, when noisy activity has not been implanted or while evaluating operation changes, it is necessary to find an environmental noise mapping prediction tool for future scenarios. When an activity is already implanted, it is possible to measure noise emissions, but this is expensive, so prediction tools can also be useful. Because of these reasons, for the last 10 years, as a response to the increasing concern for noise pollution in developed countries, several simulation m...

  14. In-Beam Background Suppression Shield

    CERN Document Server

    Santoro, V; DiJulio, D D; Ansell, S; Bentley, P M

    2015-01-01

    The long (3ms) proton pulse of the European Spallation Source (ESS) gives rise to unique and potentially high backgrounds for the instrument suite. In such a source an instrument capabilities will be limited by it's Signal to Noise (S/N) ratio. The instruments with a direct view of the moderator, which do not use a bender to help mitigate the fast neutron background, are the most challenging. For these beam lines we propose the innovative shielding of placing blocks of material directly into the guide system, which allow a minimum attenuation of the cold and thermal fluxes relative to the background suppression. This shielding configuration has been worked into a beam line model using Geant4. We study particularly the advantages of single crystal sapphire and silicon blocks .

  15. Berkeley Low Background Facility

    International Nuclear Information System (INIS)

    The Berkeley Low Background Facility (BLBF) at Lawrence Berkeley National Laboratory (LBNL) in Berkeley, California provides low background gamma spectroscopy services to a wide array of experiments and projects. The analysis of samples takes place within two unique facilities; locally within a carefully-constructed, low background laboratory on the surface at LBNL and at the Sanford Underground Research Facility (SURF) in Lead, SD. These facilities provide a variety of gamma spectroscopy services to low background experiments primarily in the form of passive material screening for primordial radioisotopes (U, Th, K) or common cosmogenic/anthropogenic products; active screening via neutron activation analysis for U,Th, and K as well as a variety of stable isotopes; and neutron flux/beam characterization measurements through the use of monitors. A general overview of the facilities, services, and sensitivities will be presented. Recent activities and upgrades will also be described including an overview of the recently installed counting system at SURF (recently relocated from Oroville, CA in 2014), the installation of a second underground counting station at SURF in 2015, and future plans. The BLBF is open to any users for counting services or collaboration on a wide variety of experiments and projects

  16. Local microwave background radiation

    OpenAIRE

    Soares, Domingos

    2006-01-01

    An inquiry on a possible local origin for the Microwave Background Radiation is made. Thermal MBR photons are contained in a system called {\\it magnetic bottle} which is due to Earth magnetic field and solar wind particles, mostly electrons. Observational tests are anticipated.

  17. Berkeley Low Background Facility

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, K. J.; Norman, E. B. [Department of Nuclear Engineering, University of California-Berkeley, CA 94720 (United States); Nuclear Science Division, Lawrence Berkeley National Laboratory, CA 94720 (United States); Smith, A. R.; Poon, A. W. P.; Chan, Y. D. [Nuclear Science Division, Lawrence Berkeley National Laboratory, CA 94720 (United States); Lesko, K. T. [Physics Division, Lawrence Berkeley National Laboratory, CA 94720 (United States)

    2015-08-17

    The Berkeley Low Background Facility (BLBF) at Lawrence Berkeley National Laboratory (LBNL) in Berkeley, California provides low background gamma spectroscopy services to a wide array of experiments and projects. The analysis of samples takes place within two unique facilities; locally within a carefully-constructed, low background laboratory on the surface at LBNL and at the Sanford Underground Research Facility (SURF) in Lead, SD. These facilities provide a variety of gamma spectroscopy services to low background experiments primarily in the form of passive material screening for primordial radioisotopes (U, Th, K) or common cosmogenic/anthropogenic products; active screening via neutron activation analysis for U,Th, and K as well as a variety of stable isotopes; and neutron flux/beam characterization measurements through the use of monitors. A general overview of the facilities, services, and sensitivities will be presented. Recent activities and upgrades will also be described including an overview of the recently installed counting system at SURF (recently relocated from Oroville, CA in 2014), the installation of a second underground counting station at SURF in 2015, and future plans. The BLBF is open to any users for counting services or collaboration on a wide variety of experiments and projects.

  18. 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.

  19. Noise from wind farms

    International Nuclear Information System (INIS)

    Noise measurements has been carried out at increasing distances from wind farms with small wind turbines (75-110 kW). Measurements were performed for different layout of the wind park (a network or a line of turbines). Prediction of the noise levels according to the Danish or the IEA method resulted in an overestimation of the total level by up to 8 dB. In order to explain these discrepancies further investigations have included: measurements of the source strength for 4 different samples of the wind turbines, more elaborate directivity measurement, a repetition of the noise measurements, a pilot study of noise propagation under windy conditions. The investigations showed that the individual differences in source strength was smaller than ±1 dB and that the directivity in directions ±60 deg. relative to downwind was in the order of -1 dB to -2dB in most of the frequency range. Consequently, both hypotheses failed to explain the observed differences between measured and predicted noise levels. New noise measurements and predictions (taking the actual source strength and directivity into account) confirmed the original findings, that noise levels are overestimated by 1 - 6 dB. Noise propagation investigations using a powerful loudspeaker showed that the effect of the terrain on the noise propagation is strongly dependent on frequency. This dependency was a function of the wind speed and in qualitative agreement with a theoretical sound propagation model. (au)

  20. 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...

  1. Partially informed noise traders

    OpenAIRE

    Aase, Knut K.; Bjuland, Terje; Øksendal, Bernt

    2012-01-01

    The single auction equilibrium of Kyle’s (1985) is studied, in which noise traders may be partially informed, or alternatively they can be manipulated. Unlike Kyle’s assumption that the quantity traded by the noise traders is independent of the asset value, we assume that the noise traders are able to correlate their trade with the true price. This has several implications for the equilibrium, one being that the informed trader’s expected profits decrease as the noise traders’ ability to corr...

  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. On 1/f Noise

    OpenAIRE

    Li, Ming; Zhao, Wei

    2012-01-01

    Due to the fact that 1/f noise gains the increasing interests in the field of biomedical signal processing and living systems, we present this introductive survey that may suffice to exhibit the elementary and the particularities of 1/f noise in comparison with conventional random functions. Three theorems are given for highlighting the particularities of 1/f noise. The first says that a random function with long-range dependence (LRD) is a 1/f noise. The secondindicates that a heavy-tailed r...

  4. Noise through Quantum Pumps

    OpenAIRE

    Polianski, M. L.; Vavilov, M. G.; Brouwer, P.W.

    2002-01-01

    We study the current noise through an unbiased quantum electron pump and its mesoscopic fluctuations for arbitrary temperatures and beyond the bilinear response. In the bilinear regime, we find the full distributions of the noise power and the current-to-noise ratio for a chaotic quantum dots with single-channel and many-channel ballistic point contacts. For a dot with many-channel point contacts we also calculate the ensemble-averaged noise at arbitrary temperature and pumping strength. In t...

  5. Updating working memory in aircraft noise and speech noise causes different fMRI activations

    OpenAIRE

    Sætrevik, Bjørn; Sörqvist, Patrik

    2014-01-01

    The present study used fMRI/BOLD neuroimaging to investigate how visual-verbal working memory is updated when exposed to three different background-noise conditions: speech noise, aircraft noise and silence. The number-updating task that was used can distinguish between “substitution processes,” which involve adding new items to the working memory representation and suppressing old items, and “exclusion processes,” which involve rejecting new items and maintaining an intact memory set. The cu...

  6. Noise and Hearing Loss: A Review

    Science.gov (United States)

    Daniel, Eileen

    2007-01-01

    Background: Noise-induced hearing loss is a major cause of deafness and hearing impairment in the United States. Though genetics and advanced age are major risk factors, temporary and permanent hearing impairments are becoming more common among young adults and children especially with the increased exposure to portable music players. Though…

  7. The Feasibility of Noise Control in a Soft Drink Plant

    Directory of Open Access Journals (Sweden)

    Fouladi Dehaghi

    2016-03-01

    Full Text Available Background “Noise” can be defined as any unwanted sound. Soft drink plants, which produce the raw materials used in most carbonated beverage factories, are sources of noise. Objectives This study investigated the noise pollution present in a soft drink CO2 gas injection plant, in order to present noise control measures. Materials and Methods The instructions specified by the canadian center for occupational health and safety (CCOHS were followed during the noise study, and a sound level meter, CEL.450 calibrated with CEL-110.2 based on ISO-9612 methods, was used to record the sound pressure level (SPL at each grid point. SPL was determined in weighting scales A and C. and a noise survey map of equivalent SPLs was drawn for each part. Each part of the floor area of the soft drink factory where SPL exceeded 85 dBA was identified from the noise survey map to determine the causes of high levels of noise. In order to reduce noise level in each part, the absorption coefficient, transmission loss, and noise reduction rate were calculated in the proposed control area. Results According to the study results, noise levels in a CO2 plant’s house and control room ranged from 88 to 102 dB and 79 to 82 dB (A, respectively. In order to reduce the amount of emitted noise in the CO2 plant house and control room, a noise control plan was implemented in each part of the facility; it was met with effective results. Conclusions The findings of this investigation have clearly revealed that plant workers are at risk of developing noise-induced hearing loss. However, after the implementation of a noise control plan in each part of the facility, the noise dose received by workers has significantly decreased. The need to implement a noise conservation program was established.

  8. INFORMATION FUSION STEADY-STATE WHITE NOISE DECONVOLUTION ESTIMATORS WITH TIME-DELAYED MEASUREMENTS AND COLORED MEASUREMENT NOISES

    Institute of Scientific and Technical Information of China (English)

    Sun Xiaojun; Deng Zili

    2009-01-01

    White noise deconvolution or input white noise estimation problem has important application backgrounds in oil seismic exploration, communication and signal processing. By the modern time series analysis method, based on the Auto-Regressive Moving Average (ARMA) innovation model, under the linear minimum variance optimal fusion rules, three optimal weighted fusion white noise deconvolution estimators are presented for the multisensor systems with time-delayed measurements and colored measurement noises. They can handle the input white noise fused filtering, prediction and smoothing problems. The accuracy of the fusers is higher than that of each local white noise estimator. In order to compute the optimal weights, the formula of computing the local estimation error cross-covariances is given. A Monte Carlo simulation example for the system with 3 sensors and the Bernoulli-Gaussian input white noise shows their effectiveness and performances.

  9. 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…

  10. The Cosmic Microwave Background

    Directory of Open Access Journals (Sweden)

    Jones Aled

    1998-01-01

    Full Text Available We present a brief review of current theory and observations of the cosmic microwave background (CMB. New predictions for cosmological defect theories and an overview of the inflationary theory are discussed. Recent results from various observations of the anisotropies of the microwave background are described and a summary of the proposed experiments is presented. A new analysis technique based on Bayesian statistics that can be used to reconstruct the underlying sky fluctuations is summarised. Current CMB data is used to set some preliminary constraints on the values of fundamental cosmological parameters $Omega$ and $H_circ$ using the maximum likelihood technique. In addition, secondary anisotropies due to the Sunyaev-Zel'dovich effect are described.

  11. Background Modelling Using Edge-Segment Distributions

    Directory of Open Access Journals (Sweden)

    Jaemyun Kim

    2013-02-01

    Full Text Available We propose an edge‐segment‐based statistical background modelling algorithm to detect the moving edges for the detection of moving objects using a static camera. Traditional pixel intensity‐based background modelling algorithms face difficulties in dynamic environments since they cannot handle sudden changes in illumination. They also bring out ghosts when a sudden change occurs in the scene. To cope with this issue, intensity and noise robust edge‐based features have emerged. However, existing edge‐pixel‐based methods suffer from scattered moving edge pixels since they cannot utilize the shape. Moreover, traditional segment‐ based methods cannot handle edge shape variations and miss moving edges when they come close to the background edges. Unlike traditional approaches, our proposed method builds the background model from ordinary training frames that may contain moving objects. Furthermore, it does not leave any ghosts behind. Moreover, our method uses an automatic threshold for every background edge distribution for matching. This makes our approach robust to illumination change, camera movement and background motion. Experiments show that our method outperforms others and can detect moving edges efficiently despite the above mentioned difficulties.

  12. Unitarity and singular backgrounds

    OpenAIRE

    Brouzakis, Nikos; Quiros, Mariano

    2013-01-01

    We compute the graviton Kaluza-Klein spectrum on a gravity-dilaton background with a naked singularity for all possible boundary conditions at the singularity which are consistent with unitary evolution. We apply methods from non-relativistic quantum mechanics with singular Schr\\"{o}dinger potentials. In general the spectrum contains a tachyon, a sign of instability. Only for a particular boundary condition at the singularity is the spectrum free of tachyons. In this case the lowest-lying gra...

  13. Australia; Background Material

    OpenAIRE

    International Monetary Fund

    1995-01-01

    This paper describes the developments in the Australian labor market during the 1990s. In 1994, a number of new labor market programs were launched, directed especially at the long-term unemployed, and a further step was taken in the evolutionary reform of the industrial relations system. The paper reviews developments in employment, wages, and productivity in Australia that formed the background to these policy initiatives. It also examines the conduct of fiscal policy at the Commonwealth an...

  14. Sri Lanka; Background Papers

    OpenAIRE

    International Monetary Fund

    1995-01-01

    This Background Paper on Sri Lanka provides information on the economic developments during 1992–95. Developments in the domestic and external sectors are discussed. The deficiencies of the official consumer price index that resulted in a substantial understatement of inflation performance in 1994 and alternative estimates of underlying inflation are described. The structural rigidities in the labor market that perpetuate high unemployment and limit job growth are also described. The paper ...

  15. Background, phenomenology, and motivation

    International Nuclear Information System (INIS)

    The authors discuss the background to the kinetics of adsorption and desorption after an elementary introduction to the problem of chemisorption in two limiting cases. Other topics discussed include the thermodynamics of adsorption, reaction mechanisms outside surfaces, and a case history of catalytic hydrogenation of carbon monoxide. Figures show the potential energy barrier as a function of an appropriate reaction coordinate, and bonding of carbon monoxide to platinum metal

  16. Some background about satellites

    Science.gov (United States)

    Burns, Joseph A.

    1986-01-01

    Four tables of planetary and satellite data are presented which list satellite discoveries, planetary parameters, satellite orbits, and satellite physical properties respectively. A scheme for classifying the satellites is provided and it is noted that most known moons fall into three general classes: regular satellites, collisional shards, and irregular satellites. Satellite processes are outlined with attention given to origins, dynamical and thermal evolution, surface processes, and composition and cratering. Background material is provided for each family of satellites.

  17. Effects of traffic noise

    Energy Technology Data Exchange (ETDEWEB)

    Gottlob, D.

    1986-02-01

    One of the main sources of noise is road traffic. In 1984 there were over 25 million cars, 1.2 million lorries, 1.3 million motor cycles and 1.6 million mopeds using our roads. Opinion polls showed that 21% of the population felt that they were affected by traffic noise as a nuisance factor. An outline of the effects of this noise on the affected population is given, illustrated by diagrams. Details about noise emissions (drive-past level) of the different types of vehicles in city traffic are stated and the effects of noise described. The author goes into the nuisance effect (noise is not a physical factor, but a psychosocial one), changes in behaviour (ways of speaking, reduction of stress on households in proportion to rising income and higher educational levels) and the consequences for health (the reaction of the body to noise is primarily a consequence of the psychosomatic organisation of ow bodies). In conclusion, the author deals with the subjective efficiency of noise protection measures. (HWJ).

  18. RB reactor noise analysis

    International Nuclear Information System (INIS)

    Statistical fluctuations of reactivity represent reactor noise. Analysis of reactor noise enables determining a series of reactor kinetic parameters. Fluctuations of power was measured by ionization chamber placed next to the tank of the RB reactor. The signal was digitized by an analog-digital converter. After calculation of the mean power, 3000 data obtained by sampling were analysed

  19. 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…

  20. EDA noise analysis

    International Nuclear Information System (INIS)

    Using orCAD Pspice EDA software, the circuit simulation and the analysis such as transient analysis, noise analysis, temperature analysis, are made for charge-sensitive preamplifier. By calculation and comparison, the result shows circuit noise responses according to the temperature changes. (authors)

  1. MOWER ATTACHMENT NOISE

    OpenAIRE

    Mosdzianowski, G.

    1990-01-01

    The noise produced by grass mowing attachments fitted to small tractors and combining a number of rotary blades with a total cutting width of up to 120 cm was investigated. The paper develops a noise reduction concept based on an analysis of sound sources.

  2. Noise-induced linearisation

    OpenAIRE

    Dykman, Mark; Luchinsky, D. G.; Mannella, R.; McClintock, Peter V. E.; Short, H. E.; Stein, N. D.; Stocks, N. G.

    1994-01-01

    It is found that the response of a nonlinear dynamical system can be linearised, and its frequency dispersion diminished, by the addition of external noise of sufficient intensity. Taking as an example an overdamped bistable system driven by a low-frequency periodic field, this noise-induced linearisation is investigated through analogue electronic experiments. The wider implications are considered.

  3. 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...

  4. Noise from wind turbines

    International Nuclear Information System (INIS)

    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)

  5. Noise Enhanced Stability

    International Nuclear Information System (INIS)

    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)

  6. Noise in coevolving networks.

    Science.gov (United States)

    Diakonova, Marina; Eguíluz, Víctor M; San Miguel, Maxi

    2015-09-01

    Coupling dynamics of the states of the nodes of a network to the dynamics of the network topology leads to generic absorbing and fragmentation transitions. The coevolving voter model is a typical system that exhibits such transitions at some critical rewiring. We study the robustness of these transitions under two distinct ways of introducing noise. Noise affecting all the nodes destroys the absorbing-fragmentation transition, giving rise in finite-size systems to two regimes: bimodal magnetization and dynamic fragmentation. Noise targeting a fraction of nodes preserves the transitions but introduces shattered fragmentation with its characteristic fraction of isolated nodes and one or two giant components. Both the lack of absorbing state for homogeneous noise and the shift in the absorbing transition to higher rewiring for targeted noise are supported by analytical approximations. PMID:26465524

  7. Noise in Coevolving Networks

    CERN Document Server

    Diakonova, Marina; Miguel, Maxi San

    2014-01-01

    Coupling dynamics of the states of the nodes of a network to the dynamics of the network topology leads to generic absorbing and fragmentation transitions. The coevolving voter model is a typical system that exhibits such transitions at some critical rewiring. We study the robustness of these transitions under two distinct ways of introducing noise. Noise affecting all the nodes destroys the absorbing-fragmentation transition, giving rise in finite-size systems to two regimes: bimodal magnetisation and dynamic fragmentation. Noise Targeting a fraction of nodes preserves the transitions but introduces shattered fragmentation with its characteristic fraction of isolated nodes and one or two giant components. Both the lack of absorbing state for homogenous noise and the shift in the absorbing transition to higher rewiring for targeted noise are supported by analytical approximations.

  8. Single and Multiple Microphone Noise Reduction Strategies in Cochlear Implants

    OpenAIRE

    Kokkinakis, Kostas; Azimi, Behnam; Hu, Yi; Friedland, David R.

    2012-01-01

    To restore hearing sensation, cochlear implants deliver electrical pulses to the auditory nerve by relying on sophisticated signal processing algorithms that convert acoustic inputs to electrical stimuli. Although individuals fitted with cochlear implants perform well in quiet, in the presence of background noise, the speech intelligibility of cochlear implant listeners is more susceptible to background noise than that of normal hearing listeners. Traditionally, to increase performance in noi...

  9. Simulation of cosmological stochastic background in LISA

    International Nuclear Information System (INIS)

    A pilot study has been carried out to simulate stochastic gravitational wave background originating from first order phase transitions in the early universe. The space based gravitational wave detector LISA will be operational in the range of 10-4 to 0.1 Hz and could be sensitive to the red shifted gravitational waves from cosmological origin. In this study we have modeled the signals from first order phase transitions and we compared the signal both with the expected instrumental noise and realistic simulated foreground signals, originating from the white dwarf population in our galaxy.

  10. Analysis and modeling on noise factor of microchannel plate

    Science.gov (United States)

    Li, Yanhong; Chen, Xiaomei; Ni, Guoqiang

    2013-12-01

    The Microchannel plate (MCP) is the main noise source of low-level light (LLL) image intensifier. Material and the whole manufacturing process of MCP have great impact on the noises of MCP. In this paper, based on the physical mechanisms of MCP, noises of MCP are classified scientifically. By using the data obtained from the actual production and the process test, the regression equation of the noise figure of MCP is derived, and the theoretical model of MCP noise figure is established, including the background noise figure model caused by the dark current of the MCP primarily about the time of the alkali corrosion technic, the ion feedback induced noise figure model caused by the patterns of the MCP channel wall primarily about the time and temperature of the hydrogen reduction technic, and the electronic scattering noise figure model caused by the open area ratio of the MCP primarily about the time of the alkali corrosion technic. Guided by the theoretical model of noise figure, the methods of suppressing noises of MCP are obtained and the technics are optimized. Taking advantage of the new techniques, the noise figure of the third generation MCP has been reduced to below 1.8.

  11. Cardiovascular effects of environmental noise: Research in Germany

    Directory of Open Access Journals (Sweden)

    Christian Maschke

    2011-01-01

    Full Text Available Research on systematic noise effects started in Germany back in the fifties with basic experimental studies on humans. As a result, noise was classified as a non-specific stressor, which could cause an ergotropic activation of the complete organism. In the light of this background research a hypothesis was proposed that long-term noise exposure could have an adverse effect on health. This hypothesis was further supported by animal studies. Since the sixties, the adverse effects of chronic road traffic noise exposure were further examined in humans with the help of epidemiological studies. More epidemiological aircraft noise studies followed in the 1970s and thereafter. The sample size was increased, relevant confounding factors were taken into account, and the exposure and health outcomes were investigated objectively and with higher quality measures. To date, more than 20 German epidemiological traffic noise studies have focused on noise-induced health effects, mainly on the cardiovascular system. In particular, the newer German noise studies demonstrate a clear association between residential exposure to traffic noise (particularly night noise and cardiovascular outcomes. Nevertheless, additional research is needed, particularly on vulnerable groups and multiple noise exposures. The epidemiological findings have still not been fully considered in German regulations, particularly for aircraft noise. The findings, however, were taken into account in national recommendations. The Federal Environment Agency recommends noise rating levels of 65 dB(A for the day and 55 dB(A for the night, as a short-term goal. In the medium term, noise rating levels of 60 / 50 (day, night should be reached and noise rating levels of 55 / 45 in the long run.

  12. Quantum Computers: Noise Propagation and Adversarial Noise Models

    OpenAIRE

    Kalai, Gil

    2009-01-01

    In this paper we consider adversarial noise models that will fail quantum error correction and fault-tolerant quantum computation. We describe known results regarding high-rate noise, sequential computation, and reversible noisy computation. We continue by discussing highly correlated noise and the "boundary," in terms of correlation of errors, of the "threshold theorem." Next, we draw a picture of adversarial forms of noise called (collectively) "detrimental noise." Detrimental noise is mode...

  13. Backgrounded but not peripheral

    DEFF Research Database (Denmark)

    Hovmark, Henrik

    DDAs in question contribute to the socio-cultural construction of identity, i.e. that they play a rather specific role in discursive communication and socio-cultural meaning construction. On the other hand it is clear that the semantics of the DDAs in question, seen in isolation, is very abstract or...... general; furthermore, the DDAs are backgrounded in discourse. Is it reasonable to claim, rather boldly, that “the informants express their identity in the use of the directional adverb ud ‘out’ etc.”? In the course of this article, however, I suggest that the DDAs in question do contribute to the socio-cultural...

  14. The Cosmic Background Radiation

    OpenAIRE

    Smoot, George; Scott, Douglas

    1997-01-01

    We review the current status of experimental data for spectral distortions and angular anisotropies of the cosmic microwave background, as well as discussing the relevant physical processes. This is one of a number of new articles in astrophysics and cosmology which will appear in the 1996 Review of Particle Properties (Phys. Rev. D. in press). Other relevant reviews include: "Big-Bang Cosmology" by K.A. Olive; "Big-Bang Nucleosynthesis" by K.A. Olive & D.N. Schramm; "The Hubble Constant" by ...

  15. Malaysia; Background Paper

    OpenAIRE

    International Monetary Fund

    1996-01-01

    This Background Paper on Malaysia examines developments and trends in the labor market since the mid-1980s. The paper describes the changes in the employment structure and the labor force. It reviews wages and productivity trends and their effects on unit labor cost. The paper highlights that Malaysia’s rapid growth, sustained since 1987, has had a major impact on the labor market. The paper outlines the major policy measures to address the labor constraints. It also analyzes Malaysia’s r...

  16. Background and introduction

    DEFF Research Database (Denmark)

    Jensen, Per Anker; van der Voordt, Theo; Coenen, Christian

    2012-01-01

    in scope between FM and CREM is that CREM has its focus on real estate as physical and economical assets utilized by an organisation, while FM has a wider service focus. The difference in scope between FM and CREM on one side and B2B marketing on the other is that FM and CREM are related to...... chapter provides important background information to understand the following chapters in this book. Research limitations: The chapter is mainly based on the experience and knowledge of the editors. It does not include original research but provides an introductory overview of the book. Originality...

  17. Family Background and Entrepreneurship

    DEFF Research Database (Denmark)

    Lindquist, Matthew J.; Sol, Joeri; Van Praag, Mirjam;

    Vast amounts of money are currently being spent on policies aimed at promoting entrepreneurship. The success of such policies, however, rests in part on the assumption that individuals are not ‘born entrepreneurs’. In this paper, we assess the importance of family background and neighborhood...... effects as determinants of entrepreneurship. We start by estimating sibling correlations in entrepreneurship. We find that between 20 and 50 percent of the variance in different entrepreneurial outcomes is explained by factors that siblings share. The average is 28 percent. Allowing for differential...... entrepreneurship does play a large role, as do shared genes....

  18. Disconnect between turbine noise guidelines and health authority recommendations

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, J.P. [Queen' s Univ., Kingston, ON (Canada). Dept. of Physics

    2008-07-01

    Wind turbine noise causes annoyance and health problems that include sleeplessness, anxiety and headaches. Universally, turbine noise limits at residences allow an intrusion of 5 to 20 dBA above background noise level in rural areas. Regulations for wind turbine siting relative to residences vary world-wide and within countries with local environmental protection jurisdictions. Some regulations specify setback distances while others specify noise limits. This paper stated that there is a disconnect between the setbacks of modern up-wind blade wind turbines from homes as recommended by health authorities and as determined from the noise guidelines of various jurisdictions. Health authorities generally recommend 1.5 to 2 km while noise guidelines allow setbacks of 400 to 500 metres. The resolution lies in the inadequacy of noise guidelines, notably the typical allowance of 10 dBA above background noise; the characteristic periodic or impulsive sound of a turbine; the continuing use, in Ontario and New Zealand, of masking from ground-level wind noise to allow permissible turbine noise to increase with wind speed; the absence of turbulent inflow noise in noise guidelines and assessments; and the lack of coherent sound reflection from the ground in the calculation of turbine noise at a receptor. The additional aerodynamic noise arising from the rotation of turbine blades in turbulent wind is not yet included in the noise limits of any jurisdictions. Calculation and measurements from the National Renewable Energy Laboratory demonstrate that this additional noise can add substantial low frequency noise, which is weakly absorbed by the atmosphere and walls. The authors emphasized that regulating authorities need to request turbulence intensity measurements and associated noise estimates in the impact assessments required before approval of wind plants. At distances of 500 m and more from a turbine, the combination of direct sound and that reflected from the ground can

  19. The Backgrounds Data Center

    Science.gov (United States)

    Snyder, W. A.; Gursky, H.; Heckathorn, H. M.; Lucke, R. L.; Berg, S. L.; Dombrowski, E. G.; Kessel, R. A.

    1993-01-01

    The Strategic Defense Initiative Organization has created data centers for midcourse, plumes, and backgrounds phenomenologies. The Backgrounds Data Center (BDC) has been designated as the prime archive for data collected by SDIO programs. The BDC maintains a Summary Catalog that contains 'metadata,' that is, information about data, such as when the data were obtained, what the spectral range of the data is, and what region of the Earth or sky was observed. Queries to this catalog result in a listing of all data sets (from all experiments in the Summary Catalog) that satisfy the specified criteria. Thus, the user can identify different experiments that made similar observations and order them from the BDC for analysis. On-site users can use the Science Analysis Facility (SAFE for this purpose. For some programs, the BDC maintains a Program Catalog, which can classify data in as many ways as desired (rather than just by position, time, and spectral range as in the Summary Catalog). For example, data sets could be tagged with such diverse parameters as solar illumination angle, signal level, or the value of a particular spectral ratio, as long as these quantities can be read from the digital record or calculated from it by the ingest program. All unclassified catalogs and unclassified data will be remotely accessible.

  20. Ambient Noise in an Urbanized Tidal Channel

    Science.gov (United States)

    Bassett, Christopher

    levels that shows good agreement with 85% of the temporal data. Bed stresses associated with currents can produce propagating ambient noise by mobilizing sediments. The strength of the tidal currents in northern Admiralty Inlet produces bed stresses in excess of 20 Pa. Significant increases in noise levels at frequencies from 4-30 kHz, with more modest increases noted from 1-4 kHz, are attributed to mobilized sediments. Sediment-generated noise during strong currents masks background noise from other sources, including vessel traffic. Inversions of the acoustic spectra for equivalent grain sizes are consistent with qualitative observations of the seabed composition. Bed stress calculations using log layer, Reynolds stress, and inertial dissipation techniques generally agree well and are used to estimate the shear stresses at which noise levels increase for different grain sizes. Ambient noise levels in one-third octave bands with center frequencies from 1 kHz to 25 kHz are dominated by sediment-generated noise and can be accurately predicted using the near-bed current velocity above a critical threshold. When turbulence is advected over a pressure sensitive transducer, the turbulent pressure fluctuations can be measured as noise, though these pressure fluctuations are not propagating sound and should not be interpreted as ambient noise. Based on measurements in both Admiralty Inlet, Puget Sound and the Chacao Channel, Chile, two models are developed for flow-noise. The first model combined measurements of mean current velocities and turbulence and agrees well with data from both sites. The second model uses scaling arguments to model the flow-noise based solely on the mean current velocity. This model agrees well with the data from the Chacao Channel but performs poorly in Admiralty Inlet, a difference attributed to differences turbulence production mechanisms. At both sites, the spectral slope of flow noise follows a f-3.2 dependence, suggesting partial cancellation of

  1. Noise and Phase Transitions

    Science.gov (United States)

    Chen, Zhi; Yu, Clare C.

    2006-03-01

    Noise is present in many physical systems and is often viewed as a nuisance. Yet it can also be a probe of microscopic fluctuations. There have been indications recently that the noise in the resistivity increases in the vicinity of the metal-insulator transition. But what are the characteristics of the noise associated with well-understood first and second order phase transitions? It is well known that critical fluctuations are associated with second order phase transitions, but do these fluctuations lead to enhanced noise? We have addressed these questions using Monte Carlo simulations to study the noise in the 2D Ising model which undergoes a second order phase transition, and in the 5-state Potts model which undergoes a first order phase transition. We monitor these systems as the temperature drops below the critical temperature. At each temperature, after equilibration is established, we obtain the time series of quantities characterizing the properties of the system, i.e., the energy and magnetization per site. We apply different methods, such as the noise power spectrum, the Detrended Fluctuation Analysis (DFA) and the second spectrum of the noise, to analyze the fluctuations in these quantities.

  2. Substation noise screening tool

    Energy Technology Data Exchange (ETDEWEB)

    Maybee, Nigel; Everton, Pascal [HFP Acoustical Consultants Corp. (Canada)], email: nigel.maybee@hfpacoustical.com; Chow, Vincent [Altalink Management Ltd. (Canada)], email: Vincent.Chow@AltaLink.ca

    2011-07-01

    Alberta noise regulations require energy-related facilities to conduct predictions on sound levels, especially for large and medium noise sources. This is usually done with well-known modelling software, but that can be disadvantageous when assessing the noise impact of smaller noise sources, such as transformer substations. This paper focuses on the development of a spreadsheet substation noise screening tool to assess the noise impact of a small transformer substation with precision and ease-of-use. Three aspects must be considered: transformer sound levels, which can be provided by the manufacturer or extracted from accepted sound level references; sound power calculations, which depend on the substation size and operating regime; and sound propagation calculations, which take into account the distance of the receptor from the substation and sound absorption by the air and ground. Comparison of results obtained with this tool with results generated by standard sound modelling software shows the utility, accuracy and ease-of-use of this screening method for assessing the noise impact of transformer substations.

  3. Gravitational wave background from binary systems

    International Nuclear Information System (INIS)

    Basic aspects of the background of gravitational waves and its mathematical characterization are reviewed. The spectral energy density parameter Ω(f), commonly used as a quantifier of the background, is derived for an ensemble of many identical sources emitting at different times and locations. For such an ensemble, Ω(f) is generalized to account for the duration of the signals and of the observation, so that one can distinguish the resolvable and unresolvable parts of the background. The unresolvable part, often called confusion noise or stochastic background, is made by signals that cannot be either individually identified or subtracted out of the data. To account for the resolvability of the background, the overlap function is introduced. This function is a generalization of the duty cycle, which has been commonly used in the literature, in some cases leading to incorrect results. The spectra produced by binary systems (stellar binaries and massive black hole binaries) are presented over the frequencies of all existing and planned detectors. A semi-analytical formula for Ω(f) is derived in the case of stellar binaries (containing white dwarfs, neutron stars or stellar-mass black holes). Besides a realistic expectation of the level of background, upper and lower limits are given, to account for the uncertainties in some astrophysical parameters such as binary coalescence rates. One interesting result concerns all current and planned ground-based detectors (including the Einstein Telescope). In their frequency range, the background of binaries is resolvable and only sporadically present. In other words, there is no stochastic background of binaries for ground-based detectors.

  4. Noise and Hearing Loss Prevention

    Science.gov (United States)

    ... Follow us on Twitter Noise Manufacturing Construction SafeInSound Noise and Hearing Loss on the NIOSH Science Blog ... Topics Publications and Products Programs Contact NIOSH NIOSH NOISE AND HEARING LOSS PREVENTION Recommend on Facebook Tweet ...

  5. Photon shot noise

    OpenAIRE

    Beenakker, C. W. J.; Patra, M.

    1999-01-01

    A recent theory is reviewed for the shot noise of coherent radiation propagating through a random medium. The Fano factor P/I (the ratio of the noise power and the mean transmitted current) is related to the scattering matrix of the medium. This is the optical analogue of Buttiker's formula for electronic shot noise. Scattering by itself has no effect on the Fano factor, which remains equal to 1 (as for a Poisson process). Absorption and amplification both increase the Fano factor above the P...

  6. NOISE POLLUTION IN MUMBAI

    OpenAIRE

    Khamkar S. P.

    2016-01-01

    According to the World Health Organization (WHO), noise is a second only to air pollution in the impact it has on health. Mumbai is the nosiest city in the world. Traffic is a continuous source of noise. 21 Century has three grave problems, namely growth of population, conicperversity and pollution. If we have to survive, pollution is the most dangerous problems like a cancer in which death is sure but slow. Maharashtra pollution Control Board (MPCB) has given zone wise noise level limits. No...

  7. Controlled Noise Seismology

    KAUST Repository

    Hanafy, Sherif M.

    2015-08-19

    We use controlled noise seismology (CNS) to generate surface waves, where we continuously record seismic data while generating artificial noise along the profile line. To generate the CNS data we drove a vehicle around the geophone line and continuously recorded the generated noise. The recorded data set is then correlated over different time windows and the correlograms are stacked together to generate the surface waves. The virtual shot gathers reveal surface waves with moveout velocities that closely approximate those from active source shot gathers.

  8. Noise: sound reactive fashion

    OpenAIRE

    Paiva, André; Catarino, André P.; Cabral, Isabel; Carvalho, Helder

    2015-01-01

    Sound and noise have an important influence in our daily lives. They can positively or negatively change our quality of life. Given the idea that it is harder to ignore what we see, rather than what we hear, the team developed a garment that senses environmental noise and shows it through lighting, to make people aware of the noise around them. The garment chosen was a jacket, with a deliberately provocative design. It is the authors’ intention to study the integration of lighting in garments...

  9. Noise blind test

    OpenAIRE

    H. Cadet

    2006-01-01

    In the aim of characterizing site condition for seismic risk, the microtremor or ambient noise studies have been developed. The main objective of this blind test is to check of the reliability of results, to observe the user subjectivity (array choice, parameters that are user depend) in the noise recordings analyze. Noise records were analysed on single-station with H/V method and with several sensors for array method to determine the dispersion characteristics of the surface-wave part of th...

  10. 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. PMID:24458659

  11. Criteria for environmental noise assessment

    OpenAIRE

    Hadzi-Nikolova, Marija; Mirakovski, Dejan; Doneva, Nikolinka

    2015-01-01

    The noise assessment generally refers to the assessment of noise impact from a specific source, such as noise originating from certain industrial plants, road traffic, and this is not always an easy task. Practically in every surrounding, a number of different sources contribute to the ambiental noise at a certain point. Standardization of noise level includes recommendations for noise level prescribed by legislation, which are enabling stay in the environment without danger to human heal...

  12. Handbook Of Noise And Vibration

    International Nuclear Information System (INIS)

    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.

  13. Holography for Schrodinger backgrounds

    CERN Document Server

    Guica, Monica; Taylor, Marika; van Rees, Balt

    2010-01-01

    We discuss holography for Schrodinger solutions of both topologically massive gravity in three dimensions and massive vector theories in (d+1) dimensions. In both cases the dual field theory can be viewed as a d-dimensional conformal field theory (two dimensional in the case of TMG) deformed by certain operators that respect the Schrodinger symmetry. These operators are irrelevant from the viewpoint of the relativistic conformal group but they are exactly marginal with respect to the non-relativistic conformal group. The spectrum of linear fluctuations around the background solutions corresponds to operators that are labeled by their scaling dimension and the lightcone momentum k_v. We set up the holographic dictionary and compute 2-point functions of these operators both holographically and in field theory using conformal perturbation theory and find agreement. The counterterms needed for holographic renormalization are non-local in the v lightcone direction.

  14. Aircraft noise and speech intelligibility in an outdoor living space.

    Science.gov (United States)

    Alvarsson, Jesper J; Nordström, Henrik; Lundén, Peter; Nilsson, Mats E

    2014-06-01

    Studies of effects on speech intelligibility from aircraft noise in outdoor places are currently lacking. To explore these effects, first-order ambisonic recordings of aircraft noise were reproduced outdoors in a pergola. The average background level was 47 dB LA eq. Lists of phonetically balanced words (LAS max,word = 54 dB) were reproduced simultaneously with aircraft passage noise (LAS max,noise = 72-84 dB). Twenty individually tested listeners wrote down each presented word while seated in the pergola. The main results were (i) aircraft noise negatively affects speech intelligibility at sound pressure levels that exceed those of the speech sound (signal-to-noise ratio, S/N aircraft noise on speech intelligibility outdoors. PMID:24907809

  15. Proceedings of a workshop on wind turbine noise

    International Nuclear Information System (INIS)

    Noise generated by wind turbines is an environmental constraint on the exploitation of wind energy. It is a major consideration when seeking planning consent for the siting of machines due to the high population density in the UK and low levels of background noise in rural areas. There is, therefore, a need to identify the sources and characteristics of noise emitted by wind turbine generators, assess the influences on the propagation of noise through the atmosphere, and provide information to both wind farm developers and planning regulators on noise levels. A one day workshop was organised to provide an opportunity for experts in the field of wind turbine noise to present the current thoughts on the subject and so allow a wide ranging discussion of particular issues of interest. This volume contains the 10 papers presented at the workshop for each of which a separate abstract has been prepared. (author)

  16. Musical Training during Early Childhood Enhances the Neural Encoding of Speech in Noise

    Science.gov (United States)

    Strait, Dana L.; Parbery-Clark, Alexandra; Hittner, Emily; Kraus, Nina

    2012-01-01

    For children, learning often occurs in the presence of background noise. As such, there is growing desire to improve a child's access to a target signal in noise. Given adult musicians' perceptual and neural speech-in-noise enhancements, we asked whether similar effects are present in musically-trained children. We assessed the perception and…

  17. Acoustics Noise Test Cell

    Data.gov (United States)

    Federal Laboratory Consortium — The Acoustic Noise Test Cell at the NASA/Caltech Jet Propulsion Laboratory (JPL) is located adjacent to the large vibration system; both are located in a class 10K...

  18. Conservative Noise Filters

    Directory of Open Access Journals (Sweden)

    Mona M.Jamjoom

    2016-05-01

    Full Text Available Noisy training data have a huge negative impact on machine learning algorithms. Noise-filtering algorithms have been proposed to eliminate such noisy instances. In this work, we empirically show that the most popular noise-filtering algorithms have a large False Positive (FP error rate. In other words, these noise filters mistakenly identify genuine instances as outliers and eliminate them. Therefore, we propose more conservative outlier identification criteria that improve the FP error rate and, thus, the performance of the noise filters. With the new filter, an instance is eliminated if and only if it is misclassified by a mutual decision of Naïve Bayesian (NB classifier and the original filtering criteria being used. The number of genuine instances that are incorrectly eliminated is reduced as a result, thereby improving the classification accuracy.

  19. Geometry And Quantum Noise

    CERN Document Server

    Barbon, Jose L F

    2014-01-01

    We study the fine structure of long-time quantum noise in correlation functions of AdS/CFT systems. Under standard assumptions of quantum chaos for the dynamics and the observables, we estimate the size of exponentially small oscillations and trace them back to geometrical features of the bulk system. The noise level is highly suppressed by the amount of dynamical chaos and the amount of quantum impurity in the states. This implies that, despite their missing on the details of Poincare recurrences, `virtual' thermal AdS phases do control the overall noise amplitude even at high temperatures where the thermal ensemble is dominated by large AdS black holes. We also study EPR correlations and find that, in contrast to the behavior of large correlation peaks, their noise level is the same in TFD states and in more general highly entangled states.

  20. Occupational Noise Exposure

    Science.gov (United States)

    ... the ear drum and are transmitted to the middle and inner ear. In the middle ear three small bones called the malleus (or ... quiet area). Restricting worker presence to a suitable distance away from noisy equipment. Controlling noise exposure through ...

  1. Active road noise reduction

    OpenAIRE

    Vraničar, Primož

    2012-01-01

    Theoretical principle of noise cancellation can be realized in the ideal studio conditions, but when the experiment is put into actual space and realized, we can see that the sound only partly cancels itself, on some frequencies more and on some less. However, in construction engineering we are not only dealing with certain frequencies but with frequency spectrums, if not with the whole frequency field. It is relatively hard to control the noise in traffic. We are dealing with a larger freque...

  2. Noise Secured Internet

    OpenAIRE

    Barbosa, Geraldo A.

    2005-01-01

    This work shows how a secure Internet can be implemented through a fast key distribution system that uses physical noise to protect the transmitted information. Starting from a shared random sequence $K_0$ between two (or more) users, longsequences $R$ of random bits can be shared. The signals sent over the Internet are deterministic but have a built-in Nature-made uncertainty that protects the shared sequences. After privacy amplification the shared $R$ random bits --encrypted by noise-- are...

  3. Nonequilibrium spin noise spectroscopy

    OpenAIRE

    Li, Fuxiang; Pershin, Yuriy V.; Slipko, Valeriy A.; Sinitsyn, Nikolai A.

    2013-01-01

    Spin Noise Spectroscopy (SNS) is an experimental approach to obtain correlators of mesoscopic spin fluctuations in time by purely optical means. We explore the information that this technique can provide when it is applied to a weakly non-equilibrium regime when an electric current is driven through a sample by an electric field. We find that the noise power spectrum of conducting electrons experiences a shift, which is proportional to the strength of the spin-orbit coupling for electrons mov...

  4. Noise in Biology

    OpenAIRE

    Tsimring, Lev S

    2014-01-01

    Noise permeates biology on all levels, from the most basic molecular, sub-cellular processes to the dynamics of tissues, organs, organisms, and populations. The functional roles of noise in biological processes can vary greatly. Along with standard, entropy-increasing effects of producing random mutations, diversifying phenotypes in isogenic populations, limiting information capacity of signaling relays, it occasionally plays more surprising constructive roles by accelerating the pace of evol...

  5. Gravitational Wave Confusion Noise

    OpenAIRE

    Cornish, Neil J.

    2003-01-01

    One of the greatest challenges facing gravitational wave astronomy in the low frequency band is the confusion noise generated by the vast numbers of unresolved galactic and extra galactic binary systems. Estimates of the binary confusion noise suffer from several sources of astrophysical uncertainty, such as the form of the initial mass function and the star formation rate. There is also considerable uncertainty about what defines the confusion limit. Various ad-hoc rules have been proposed, ...

  6. ENDOGENOUS NOISE TRADERS

    OpenAIRE

    Salomonsson, Marcus

    2006-01-01

    We construct a parsimonious model of a financial market where the marginal investor is an endogenous noise trader. Such a trader anticipates that future shocks may force him to exit his position. In compensation he requires a higher return. We show that the original seller of the asset pays the required return. This can only be optimal if the seller has access to an investment opportunity that gives a sufficiently high return, compared to the noise trader's investment opportunities. We also s...

  7. Noise Stabilized Random Attractor

    OpenAIRE

    Finn, J.M.; Tracy, E. R.; Cooke, W. E.; Richardson, A. S.

    2005-01-01

    A two dimensional flow model is introduced with deterministic behavior consisting of bursts which become successively larger, with longer interburst time intervals between them. The system is symmetric in one variable x and there are bursts on either side of x = 0, separated by the presence of an invariant manifold at x = 0. In the presence of arbitrarily small additive noise in the x direction, the successive bursts have bounded amplitudes and interburst intervals. This system with noise is ...

  8. Progress in Understanding the Diffuse UV Cosmic Background

    OpenAIRE

    Henry, Richard Conn

    2012-01-01

    I report on progress in my ongoing work with Professor Jayant Murthy concerning the origin and nature of the diffuse ultraviolet background radiation over the sky. We have obtained and are reducing a vast trove of Voyager ultraviolet spectrometer observations of the diffuse background shortward of Lyman alpha, including for the first time measurements made from the outermost regions of the solar system, where noise from solar-system scattered (and then grating-scattered) solar Lyman alpha is ...

  9. Gas plant environmental noise

    International Nuclear Information System (INIS)

    In September 1988, the Energy Resources Conservation Board which regulates the Alberta oil and gas industry tightened its environmental noise guidelines by a factor of 10. New nighttime maximum permissible noise levels as low as 40 dBA are now enforceable in rural areas. The directive is retroactively applicable upon residential complaints and necessitated the use of radical innovations for industry to comply. Details are presented of noise and noise parameters, acoustic fields, dissipation, absorption and diffraction. Major sources of gas plant noise are engine and turbine exhausts, air coolers and cooling towers, purge blowers for electric motors, piping and valves, and flares. Attenuation techniques include silencers, berms and dykes, acoustic lagging and housing, variable speed drives, and stack induced air draft cooler. Recommendations for noise abatement include: house all rotating equipment in acoustically lined buildings; muffle engine exhausts and purge blower vents with reactive silencers where possible; choose electric over engine driven equipment; keep a good mix of engine speeds, fan speeds, and blade counts to reduce tonal spikes; don't rely on berms or dykes; choose water cooling towers over aerial coolers and fit aerial coolers with variable speed drive fans; experiment with stack induced draft coolers where water cooling is not an option; and use process speed valves where possible over bypass valving. 18 figs

  10. Noise composed of multiplication of two dichotomous noises

    Institute of Scientific and Technical Information of China (English)

    Li Jing-Hui

    2008-01-01

    In this paper, we introduce a noise which is composed of multiplication of two dichotomous noises, and derive the probability density and the statistical properties of this noise. The obtained results can help study the resonant activation phenomenon, the phenomenon of stochastic resonance, the transport of particles, and the nonequilibrium (phase) transition for the systems driven by this noise.

  11. A Comparison of seismic instrument noise coherence analysis techniques

    Science.gov (United States)

    Ringler, A.T.; Hutt, C.R.; Evans, J.R.; Sandoval, L.D.

    2011-01-01

    The self-noise of a seismic instrument is a fundamental characteristic used to evaluate the quality of the instrument. It is important to be able to measure this self-noise robustly, to understand how differences among test configurations affect the tests, and to understand how different processing techniques and isolation methods (from nonseismic sources) can contribute to differences in results. We compare two popular coherence methods used for calculating incoherent noise, which is widely used as an estimate of instrument self-noise (incoherent noise and self-noise are not strictly identical but in observatory practice are approximately equivalent; Holcomb, 1989; Sleeman et al., 2006). Beyond directly comparing these two coherence methods on similar models of seismometers, we compare how small changes in test conditions can contribute to incoherent-noise estimates. These conditions include timing errors, signal-to-noise ratio changes (ratios between background noise and instrument incoherent noise), relative sensor locations, misalignment errors, processing techniques, and different configurations of sensor types.

  12. Genetical background of intelligence.

    Science.gov (United States)

    Junkiert-Czarnecka, Anna; Haus, Olga

    2016-01-01

    Intelligence as an ability to reason, think abstractly and adapt effectively to the environment is a subject of research in the field of psychology, neurobiology, and in the last twenty years genetics as well. Genetical testing of twins carried out from XX century indicated heritebility of intelligence, therefore confirmed an influence of genetic factor on cognitive processes. Studies on genetic background of intelligence focus on dopaminergic (DRD2, DRD4, COMT, SLC6A3, DAT1, CCKAR) and adrenergic system (ADRB2, CHRM2) genes as well as, neutrofins (BDNF) and oxidative stress genes (LTF, PRNP). Positive effect of investigated gene polymorphism was indicated by variation c.957C>T DRD2 gene (if in polymorphic site is thymine), polymorphism c.472G>A COMT gene (presence of adenine) and also gene ADRB2 c.46A->G (guanine), CHRM2 (thymine in place c.1890A>T) and BDNF (guanine in place c.472G>A) Obtained results indicate that intelligence is a feature dependent not only on genetic but also an environmental factor. PMID:27333929

  13. Biological aerosol background characterization

    Science.gov (United States)

    Blatny, Janet; Fountain, Augustus W., III

    2011-05-01

    To provide useful information during military operations, or as part of other security situations, a biological aerosol detector has to respond within seconds or minutes to an attack by virulent biological agents, and with low false alarms. Within this time frame, measuring virulence of a known microorganism is extremely difficult, especially if the microorganism is of unknown antigenic or nucleic acid properties. Measuring "live" characteristics of an organism directly is not generally an option, yet only viable organisms are potentially infectious. Fluorescence based instruments have been designed to optically determine if aerosol particles have viability characteristics. Still, such commercially available biological aerosol detection equipment needs to be improved for their use in military and civil applications. Air has an endogenous population of microorganisms that may interfere with alarm software technologies. To design robust algorithms, a comprehensive knowledge of the airborne biological background content is essential. For this reason, there is a need to study ambient live bacterial populations in as many locations as possible. Doing so will permit collection of data to define diverse biological characteristics that in turn can be used to fine tune alarm algorithms. To avoid false alarms, improving software technologies for biological detectors is a crucial feature requiring considerations of various parameters that can be applied to suppress alarm triggers. This NATO Task Group will aim for developing reference methods for monitoring biological aerosol characteristics to improve alarm algorithms for biological detection. Additionally, they will focus on developing reference standard methodology for monitoring biological aerosol characteristics to reduce false alarm rates.

  14. Wind Turbines: Unsteady Aerodynamics and Inflow Noise

    DEFF Research Database (Denmark)

    Broe, Brian Riget

    the highest emphasis in semi-empirical models. However it is an open question whether inflow noise has a high emphasis. This illustrates the need to investigate and improve the semi-empirical model for noise due to atmospheric turbulence. Three different aerodynamical models are investigated...... (Sears, W. R.: 1941; and Graham, J. M. R.: 1970). An acoustic model is investigated using a model for the lift distribution as input (Amiet, R. K.: 1975, Acoustic radiation from an airfoil in a turbulent stream). The two models for lift distribution are used in the acoustic model. One of the models...... profile. Comparison of the aerodynamical models with data shows that the models capture the general characteristics of the measurements, but the data are hampered by background noise from the fan propellers in the wind tunnel. The measurements are in between the completely anisotropic turbulent model...

  15. Low background infrared (LBIR) facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Low background infrared (LBIR) facility was originally designed to calibrate user supplied blackbody sources and to characterize low-background IR detectors and...

  16. Hanford Site background: Part 1, Soil background for nonradioactive analytes

    International Nuclear Information System (INIS)

    Volume two contains the following appendices: Description of soil sampling sites; sampling narrative; raw data soil background; background data analysis; sitewide background soil sampling plan; and use of soil background data for the detection of contamination at waste management unit on the Hanford Site

  17. Aircraft noise - Different ways to monitor the noise load

    Science.gov (United States)

    Bekebrede, G.

    Measures taken by the Dutch government to reduce aircraft-noise disturbances including the establishment of noise zones in which subsequent building is forbidden, while already existing homes are provided with noise insulation are discussed. To ensure accurate noise monitoring, the following recommendations were made by the NLR: (1) regular noise load calculations, utilizing aircraft noise and performance data, the air traffic mix, and flight route information; (2) flight track monitoring, performed by a computerized Flight Track and Aircraft Noise Monitoring System which identifies all aircraft deviating from the prescribed track (i.e., flying over congested regions); and (3) actual noise monitoring, to guard the noise level at a specific noise-sensitive area in close proximity to the airfield, such as a hospital.

  18. Intrinsic noise-induced phase transitions: beyond the noise interpretation

    OpenAIRE

    Carrillo, O.; Ibanes, M.; Garcia-Ojalvo, J.; Casademunt, J.; Sancho, J.M.

    2003-01-01

    We discuss intrinsic noise effects in stochastic multiplicative-noise partial differential equations, which are qualitatively independent of the noise interpretation (Ito vs. Stratonovich), in particular in the context of noise-induced ordering phase transitions. We study a model which, contrary to all cases known so far, exhibits such ordering transitions when the noise is interpreted not only according to Stratonovich, but also to Ito. The main feature of this model is the absence of a line...

  19. Noise exposure assessment with task-based measurement in complex noise environment

    Institute of Scientific and Technical Information of China (English)

    LI Nan; YANG Qiu-ling; ZENG Lin; ZHU Liang-liang; TAO Li-yuan; ZHANG Hua; ZHAO Yi-ming

    2011-01-01

    Background Task-based measurement (TBM) is a method to assess the eight-hour A-weighted equivalent noise exposure level (LAeq. 8h) besides dosimeter. TBM can be better used in factories by non-professional workers and staffs.However, it is still not clear if TBM is equal or similar with dosimeter for LAeq.8h measurement in general. This study considered the measurement with dosimeter as real personal noise exposure level (PNEL) and assessed the accuracy of TBM by comparing the consistencies of TBM and dosimeter in LAeq.8h measurement.Methods The study was conducted in one automobile firm among 387 workers who are exposed to unstable noise.Dosimeters and TBM were used to compare the two strategies and assess the degree of agreement and causes of disagreement. Worker's PNEL was measured via TBM for noise; the real PNEL was also recorded. The TBM for noise was computed with task/position noise levels measured via sound level meter and workers' exposure information collected via working diary forms (WDF) filled by participants themselves. Full-shift noise exposure measurement via personal noise dosimeters were taken as the real PNEL. General linear model (GLM) was built to analyze the accuracy of TBM for noise and the source of difference between TBM for noise and real PNEL.Results The LAeq.8h with TBM were slightly higher than the real PNELs, except the electricians. Differences of the two values had statistical significance in stamping workers (P <0.001), assembly workers (P=0.015) and welding workers (P=0.001). The correlation coefficient of LAeq.8h with TBM and real PNELs was 0.841. Differences of the two results were mainly affected by real PNEL (F=11.27, P=0.001); and work groups (F=3.11, P <0.001) divided by jobs and workshops were also independent factors. PNEL of workers with fixed task/position ((86.53±8.82) dB(A)) was higher than those without ((75.76±9.92) dB(A)) (t=8.84, P <0.01). Whether workers had fixed task/position was another factor on the

  20. 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 be...

  1. 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...

  2. Reducing environmental noise impacts: A USAREUR noise management program handbook

    Science.gov (United States)

    Feather, Timothy D.; Shekell, Ted K.

    1991-06-01

    Noise pollution is a major environmental problem faced by the U.S. Army in Europe. Noise-related complaints from German citizens can escalate into intense political issues in German communities. This in turn hampers efficient operation of military training and often times threatens the Army's mission. In order to remedy these problems, USAREUR has developed a noise management program. A successful noise management program will limit the impact of unavoidable noise on the populace. This report, a component of the noise management program, is a reference document for noise management planning. It contains guidelines and rules-of-thumb for noise management. This document contains procedures which operation and training level personnel can understand and apply in their day to day noise management planning. Noise mitigation tips are given. Basic technical information that will aid in understanding noise mitigation is provided along with noise management through land use planning. Noise management for specific components of the military community, (airfields, base operations, training areas, and housing and recreation areas) are addressed. The nature of noise generated, means of noise abatement at the source, path, and receiver (both physical and organizational/public relations methods), and a case study example are described.

  3. Saliva Cortisol and Exposure to Aircraft Noise in Six European Countries

    OpenAIRE

    Selander, Jenny; Bluhm, Gösta; Theorell, Töres; Pershagen, Göran; Babisch, Wolfgang; Seiffert, Ingeburg; Houthuijs, Danny; Breugelmans, Oscar; Vigna-Taglianti, Federica; Antoniotti, Maria Chiara; Velonakis, Emmanuel; Davou, Elli; Dudley, Marie-Louise; Järup, Lars

    2009-01-01

    Background Several studies show an association between exposure to aircraft or road traffic noise and cardiovascular effects, which may be mediated by a noise-induced release of stress hormones. Objective Our objective was to assess saliva cortisol concentration in relation to exposure to aircraft noise. Method A multicenter cross-sectional study, HYENA (Hypertension and Exposure to Noise near Airports), comprising 4,861 persons was carried out in six European countries. In a subgroup of 439 ...

  4. Assessment of noise pollution indices in Birjand old districts in 2010

    OpenAIRE

    Nargess Moasheri; Mohammad Reza Monazzam Esmaeelpoore; Vahideh Abolhasannejad; Mahdi Abbaszadeh; Edris Movahedi

    2013-01-01

    Background and Aim: Noise pollution is recognized as a major problem in urban areas. Therefore, the current study was aimed to determine noise pollution indices in Birjand old districts. Materials and Methods: In this cross-sectional and analytical-descriptive study, noise measurement was performed by means of "CEL" sound level meter (model 450.490). Equivalent noise level "Leq 10 min" was measured within four daily periods and within two periods at night, according to the procedures recom...

  5. Effects of Domain-Specific Noise on Visual Motion Processing in Schizophrenia

    OpenAIRE

    Chen, Yue; Norton, Daniel; McBain, Ryan

    2014-01-01

    Background: Visual perception impairments in schizophrenia stem from abnormal information processing. Information processing requires neural response to a stimulus (signal) against a backdrop of 1) random variation in baseline neural activity (internal noise) and sometimes irrelevant environmental stimulation (external noise). Filtering out noise is a critical aspect of information processing, and needs to be critically examined in schizophrenia. Methods: To understand how noise in the visual...

  6. Lateralization of Music Processing with Noises in the Auditory Cortex: An fNIRS Study

    OpenAIRE

    Hendrik eSantosa; Melissa Jiyoun Hong; Keum-Shik eHong

    2014-01-01

    The present study is to determine the effects of background noise on the hemispheric lateralization in music processing by exposing fourteen subjects to four different auditory environments: music segments only, noise segments only, music+noise segments, and the entire music interfered by noise segments. The hemodynamic responses in both hemispheres caused by the perception of music in 10 different conditions were measured using functional near-infrared spectroscopy. As a feature to distingui...

  7. Lateralization of music processing with noises in the auditory cortex: an fNIRS study

    OpenAIRE

    Santosa, Hendrik; Hong, Melissa Jiyoun; Hong, Keum-Shik

    2014-01-01

    The present study is to determine the effects of background noise on the hemispheric lateralization in music processing by exposing 14 subjects to four different auditory environments: music segments only, noise segments only, music + noise segments, and the entire music interfered by noise segments. The hemodynamic responses in both hemispheres caused by the perception of music in 10 different conditions were measured using functional near-infrared spectroscopy. As a feature to distinguish s...

  8. Aircraft noise and its nearfield propagation computations

    Science.gov (United States)

    Zhang, Xin

    2012-08-01

    Noise generated by civil transport aircraft during take-off and approach-to-land phases of operation is an environmental problem. The aircraft noise problem is firstly reviewed in this article. The review is followed by a description and assessment of a number of sound propagation methods suitable for applications with a background mean flow field pertinent to aircraft noise. Of the three main areas of the noise problem, i.e. generation, propagation, and radiation, propagation provides a vital link between near-field noise generation and far-field radiation. Its accurate assessment ensures the overall validity of a prediction model. Of the various classes of propagation equations, linearised Euler equations are often casted in either time domain or frequency domain. The equations are often solved numerically by computational aeroacoustics techniques, bur are subject to the onset of Kelvin-Helmholtz (K-H) instability modes which may ruin the solutions. Other forms of linearised equations, e.g. acoustic perturbation equations have been proposed, with differing degrees of success.

  9. Aircraft noise and its nearfield propagation computations

    Institute of Scientific and Technical Information of China (English)

    Xin Zhang

    2012-01-01

    Noise generated by civil transport aircraft during take-off and approach-to-land phases of operation is an environmental problem.The aircraft noise problem is firstly reviewed in this article.The review is followed by a description and assessment of a number of sound propagation methods suitable for applications with a background mean flow field pertinent to aircraft noise.Of the three main areas of the noise problem,i.e.generation,propagation,and radiation,propagation provides a vital link between near-field noise generation and far-field radiation.Its accurate assessment ensures the overall validity of a prediction model.Of the various classes of propagation equations,linearised Euler equations are often casted in either time domain or frequency domain.The equations are often solved numerically by computational aeroacoustics techniques,bur are subject to the onset of Kelvin-Helmholtz (K-H) instability modes which may ruin the solutions. Other forms of linearised equations,e.g.acoustic perturbation equations have been proposed,with differing degrees of success.

  10. The influence of continuous and intermittent traffic noise on sleep

    Science.gov (United States)

    Eberhardt, J. L.; Stråle, L.-O.; Berlin, M. H.

    1987-08-01

    The effects of road traffic noise on sleep were studied in the laboratory using nine young male adults (aged 20-26). The subjects were exposed to noise with different temporal characteristics: (i) continuous traffic noise of 36 dB(A) or 45 dB(A), (ii) intermittent noise of 50 truck passages with L pmax = 45 dB(A) ( L eq = 29 dB(A)) or L pmax = 55 dB(A) ( L eq = 36 dB(A)), and (iii) a combination of continuous (45 dB(A)) and intermittent ( L pmax = 55 dB(A)) traffic noise. For one noise condition (intermittent 55 dB(A)) the effect of the use of ear plugs was also studied. The intermittent noise of L pmax = 45 dB(A) caused transitions towards lighter sleep, whereas 55 dB(A) was needed to induce awakening effects. It could be shown that the probability for arousal reactions depends on the emergence of the noise peaks from the background, rather than the absolute noise peak level. Continuous traffic noise of 45 dB(A) caused REM sleep deficits, while intermittent traffic noise of L pmax = 45 dB(A) caused stage III+IV deficits. The night with ear plugs was virtually undisturbed. After nights with REM sleep deficits the subjective sleep quality was rated lower and mood was influenced adversely. For the types of exposure used in the present investigation L eq alone is not an adequate descriptor of the noise dose, relating to the sleep disturbances observed. From the present experiment, together with other existing data, it might be concluded that the WHO recommendation of L eq = 35 dB(A) is adequate, but should be supplemented with a maximum noise level, as expressed for example in L pmax or LI, that should not be exceeded.

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

    Science.gov (United States)

    Witold Stadler, Adam; Kolek, Andrzej; Zawiślak, Zbigniew; Mleczko, Krzysztof; Jakubowska, Małgorzata; Rafał Kiełbasiński, Konrad; Młożniak, Anna

    2010-07-01

    Low-frequency noise spectroscopy has been used to examine noise properties of Pb/Cd-free RuO2- and CaRuO3-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 Cbulk. 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 RuO2 layers noise increases most likely due to larger grain size of RuO2 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 Cint. Pb/Cd-free RuO2-based resistive pastes form well-behaved interfaces with various Ag-based conductive pastes. In contrast, CaRuO3-based paste forms bad contacts with AgPd terminations because the density of TANSs increases in the interface area.

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

    International Nuclear Information System (INIS)

    Low-frequency noise spectroscopy has been used to examine noise properties of Pb/Cd-free RuO2- and CaRuO3-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 Cbulk. 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 RuO2 layers noise increases most likely due to larger grain size of RuO2 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 Cint. Pb/Cd-free RuO2-based resistive pastes form well-behaved interfaces with various Ag-based conductive pastes. In contrast, CaRuO3-based paste forms bad contacts with AgPd terminations because the density of TANSs increases in the interface area.

  13. Noise and Function

    CERN Document Server

    Weinstein, Steven

    2016-01-01

    Noise is widely understood to be something that interferes with a signal or process. Thus, it is generally thought to be destructive, obscuring signals and interfering with function. However, early in the 20th century, mechanical engineers found that mechanisms inducing additional vibration in mechanical systems could prevent sticking and hysteresis. This so-called "dither" noise was later introduced in an entirely different context at the advent of digital information transmission and recording in the early 1960s. Ironically, the addition of noise allows one to preserve information that would otherwise be lost when the signal or image is digitized. As we shall see, the benefits of added noise in these contexts are closely related to the phenomenon which has come to be known as stochastic resonance, the original version of which appealed to noise to explain how small periodic fluctuations in the eccentricity of the earth's orbit might be amplified in such a way as to bring about the observed periodic transiti...

  14. Airport noise and teratogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Edmonds, L.D.; Layde, P.M.; Erickson, J.D.

    1979-07-01

    It has been suggested that exposure to high-noise levels near major airports may cause increased incidence of birth defects in the offspring of parents residing near these airports. Using data gathered in Metropolitan Atlanta during 1970 to 1972, we compared the rates of seventeen categories of defects in high- and low-noise census tracts. No significant differences were observed. However, when we subdivided the category of central nervous system defects into several subcategories of specific defects, we noted a significantly increased incidence of spina bifida without hydrocephalus in the high-noise areas. Because of the small number of cases associated with this finding we did a matched case-control study using all cases of central nervous system defects born during the years 1968 to 1976. No significantly increased risk for residents in the high-noise areas was noted in this study. It is our opinion that noise or other factors associated with residence near airports are unlikely to be important environmental teratogens.

  15. Extraaural effects of noise

    Energy Technology Data Exchange (ETDEWEB)

    Marth, E.; Gruber, M.; Koeck, M.; Moese, J.R.; Gallasch, E.; Fueger, G.F.

    This study investigates the effects of a short-term exposition (15 sec) to an indifferent, broad spectrum of noise. Noise levels were set at 85 dB(A) and 110 dB(A). Stress mediators and compensatory mechanisms were studied in 30 test persons. The study was particularly concerned with the metabolic processes providing energy for fight or flight reactions. Most importantly triglycerides are hydrolysed in order to be able to produce the fatty acids that are released. This catabolism is a function of an ACTH-activated lipase. In 93% of the person tested, triglycerides decreased by 7 to 40% of the initial concentration. Blood sugar reaction can be described in two phases: Initially, there was a slight increase in the blood sugar concentration; at higher noise levels, it was followed by a slight decrease. This behaviour was even more characteristic of the insulin concentration. At 85 dB(A), no significant difference concentration was found compared with the levels previous to noise exposition. At 110 dB(A), there was a significant decrease in the insulin level. Vaso constriction of the peripheral blood vessels is a useful parameter for the stress caused by noise. This was shown by registering the finger pulse during the test.

  16. Natural and man-made terrestrial electromagnetic noise: an outlook

    Directory of Open Access Journals (Sweden)

    A. Meloni

    2007-06-01

    Full Text Available The terrestrial environment is continuously exposed to electromagnetic radiations which set up a «background» electromagnetic noise. Within the Non Ionizing Radiation band (NIR, i.e. for frequencies lower than 300 GHz, this background can have a natural or an artificial origin. Natural origins of electromagnetic radiations are generally atmospheric or cosmic while artificial origins are technological applications, power transmission, communications, etc. This paper briefly describes the natural and man-made electromagnetic noise in the NIR band. Natural noise comes from a large variety of sources involving different physical phenomena and covering a wide range of frequencies and showing various propagation characteristics with an extremely broad range of power levels. Due to technological growth man-made electromagnetic noise is nowadays superimposed on natural noise almost everywhere on Earth. In the last decades man-made noise has increased dramatically over and above the natural noise in residential and business areas. This increase has led some scientists to consider possible negative effects of electromagnetic waves on human life and living systems in general. Accurate measurements of natural and man-made electromagnetic noise are necessary to understand the relative power levels in the different bands and their influence on life.

  17. Traffic noise and cardiovascular disease

    OpenAIRE

    Selander, Jenny

    2010-01-01

    Traffic noise is an increasing problem in urban areas worldwide, but health effects in relation to traffic noise exposure are not well understood. Several studies show that noise may give rise to acute stress reactions, possibly leading to cardiovascular effects, but the evidence is limited on cardiovascular risks associated with traffic noise exposure. Cardiovascular effects have been indicated for other environmental stressors such as occupational noise exposure and job ...

  18. Lower Hearing Threshold by Noise

    Institute of Scientific and Technical Information of China (English)

    龙长才; 邵峰; 张燕萍; 秦佑国

    2004-01-01

    We demonstrate that noise can be a benefit factor that enables us to hear weaker signals. We measured the hearing thresholds of subjects for pure tone in different noise levels. The results show that pure tone thresholds with noise of some levels are lower than that without noise. The largest down-shift of the threshold by noise among the examined subjects is 5. 7dB, and the smallest is 1.7dB.

  19. Double Layered-Background Removal Filter for Detecting Small Infrared Targets in Heterogenous Backgrounds

    Science.gov (United States)

    Kim, Sungho

    2011-01-01

    Detecting small targets is essential for mitigating the sea-based Infrared search and track (IRST) problem. It is easy to detect small targets in homogeneous backgrounds such as the sky. When targets are on the border line of heterogeneous backgrounds such as the horizon in the sky and sea surface, solving the problem of detection becomes difficult. This paper presents a novel spatial filtering method, called Double Layered-Background Removal Filter (DL-BRF), for achieving high detection rates and low false alarm rates. DL-BRF consists of a Modified-Mean Subtraction Filter (M-MSF) and a consecutive Local-Directional Background Removal Filter (L-DBRF). M-MSF enhances the target signal and reduces background noise. L-DBRF removes horizontal structures, which upgrade the signal-to-clutter ratio and background suppression factor. L-DBRF used after M-MSF enhances the synergistic performance of horizontal target detection. Additionally, the adaptive Hysteresis threshold-based scheme is a suitable detection method. We validate the superior performance of the proposed method via three types of evaluation tests, including a real test scenario.

  20. The effect of human activity noise on the acoustic quality in open plan office

    DEFF Research Database (Denmark)

    Dehlbæk, Tania Stenholt; Jeong, Cheol-Ho; Brunskog, Jonas;

    2016-01-01

    A disadvantage of open plan offices is the noise annoyance. Noise problems in open plan offices have been dealt with in several studies, and standards have been set up. Still, what has not been taken into account is the effect of human activity noise on acoustic conditions. In this study......, measurements of the general office noise levels and the room acoustic conditions according to ISO 3382-3 have been carried out in five open plan offices. Probability density functions of the sound pressure level have been obtained, and the human activity noise has been identified. Results showed a decrease in...... D2,S have an impact on the variation in the activity noise. At 1 kHz, the technical background noise influences human activity noise positively. In both octave bands, the human activity noise level varies significantly with the office type, from a call center to a lawyer’s office....

  1. Important trends in the assessment and regulation of wind turbine noise

    International Nuclear Information System (INIS)

    Wind turbine noise assessments are used to mitigate potential negative impacts associated with wind turbines. This PowerPoint presentation reviewed recent wind turbine noise assessment trends and regulations in Canada. The noise assessment best practices guide from 2007 was discussed, and recent noise assessment developments in Ontario were reviewed. Methods of auditing wind turbine noise were evaluated and issues related to the propagation of sound over water were discussed. The impacts of noise on human health were also discussed. It was suggested that the best practices guide is in need of updating in relation to the potential health impacts of turbines and as well as a result of new setback and audit requirements. Known margins of error pose a risk to developers. The statistical variability of noise impacts and the difficulty of separating background noises from wind turbine noise data must be considered. Long-term monitoring at several points is needed to ensure accurate data collection. tabs., figs.

  2. Updating working memory in aircraft noise and speech noise causes different fMRI activations.

    Science.gov (United States)

    Saetrevik, Bjørn; Sörqvist, Patrik

    2015-02-01

    The present study used fMRI/BOLD neuroimaging to investigate how visual-verbal working memory is updated when exposed to three different background-noise conditions: speech noise, aircraft noise and silence. The number-updating task that was used can distinguish between "substitution processes," which involve adding new items to the working memory representation and suppressing old items, and "exclusion processes," which involve rejecting new items and maintaining an intact memory set. The current findings supported the findings of a previous study by showing that substitution activated the dorsolateral prefrontal cortex, the posterior medial frontal cortex and the parietal lobes, whereas exclusion activated the anterior medial frontal cortex. Moreover, the prefrontal cortex was activated more by substitution processes when exposed to background speech than when exposed to aircraft noise. These results indicate that (a) the prefrontal cortex plays a special role when task-irrelevant materials should be denied access to working memory and (b) that, when compensating for different types of noise, either different cognitive mechanisms are involved or those cognitive mechanisms that are involved are involved to different degrees. PMID:25352319

  3. 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...

  4. Shot Noise in Graphene

    OpenAIRE

    DiCarlo, L.; Williams, J.R.; Zhang, Yiming; McClure, D. T.; Marcus, C. M.

    2007-01-01

    We report measurements of current noise in single- and multi-layer graphene devices. In four single-layer devices, including a p-n junction, the Fano factor remains constant to within +/-10% upon varying carrier type and density, and averages between 0.35 and 0.38. The Fano factor in a multi-layer device is found to decrease from a maximal value of 0.33 at the charge-neutrality point to 0.25 at high carrier density. These results are compared to theoretical predictions for shot noise in balli...

  5. Community response to noise

    Directory of Open Access Journals (Sweden)

    Takashi Yano

    2012-01-01

    Full Text Available Activities from 2008 to 2011 by ICBEN community response to noise team were summarized. That is, individual community-based indexes such as community tolerance Level, Zuricher Fluglarm Index (ZFI and Frankfurter Fluglarm Index (FFI/FNI were newly proposed, differences in railway bonus between Europe and Asia were discussed by a Swedish survey, socio-acoustic surveys were reported from developing countries, and annoyance equivalents and dominant source models were proposed as the adequate combined noise model. Furthermore, not only negative, but also positive aspects of sound were discussed as soundscape studies. Finally, seven items were listed as future team activities.

  6. Ancient noise generators

    Science.gov (United States)

    Beristain, Sergio; Menchaca, Rolando; Velazquez, Roberto

    2002-11-01

    There has been found a whole family of similar artifacts which produce singing noises. These noises sometimes resemble those sounds generated by some animals and/or naturally produced by strong winds passing through holes and edges. It means that these sounds have wide frequency spectrums and very often some clear tones are identified. The original purpose of these artifacts is unknown, but some researchers think that some were used in mortuary ceremonies and employed by H-men. The Olmecan whistle previously presented belongs to this family, and now it is compared with a bone or wooden instrument shown in the Florentine codex.

  7. Noise Source Location Optimization

    Directory of Open Access Journals (Sweden)

    Ed O’Keefe

    1994-01-01

    Full Text Available This article describes a method to determine locations of noise sources that minimize modal coupling in complex acoustic volumes. Using the acoustic source scattering capabilities of the boundary element method, predictions are made of mode shape and pressure levels due to various source locations. Combining knowledge of the pressure field with a multivariable function minimization technique, the source location generating minimum pressure levels can be determined. The analysis also allows for an objective comparison of “best/worst” locations. The technique was implemented on a personal computer for the U.S. Space Station, predicting 5–10 dB noise reduction using optimum source locations.

  8. Environmental propagation of noise in mines and nearby villages: A study through noise mapping

    Directory of Open Access Journals (Sweden)

    Veena D Manwar

    2016-01-01

    Full Text Available Background: Noise mapping being an established practice in Europe is hardly practiced for noise management in India although it is mandatory in Indian mines as per guidelines of the Directorate General of Mines Safety (DGMS. As a pilot study, noise mapping was conducted in an opencast mine with three different models; one based on the baseline operating conditions in two shifts (Situation A, and two other virtual situations where either production targets were enhanced by extending working hours to three shifts (Situation B or only by increased mechanization and not changing the duration of work (Situation C. Methods: Noise sources were categorized as point, line, area, and moving sources. Considering measured power of the sources, specific meteorological and geographical parameters, noise maps were generated using Predictor LimA software. Results: In all three situations, Lden values were 95 dB(A and 70–80 dB(A near drill machine and haul roads, respectively. Noise contours were wider in Situation C due to increase in frequency of dumpers. Lden values near Shovel 1 and Shovel 2 under Situation B increased by 5 dB and 3 dB, respectively due to expansion of working hours. In Situation C, noise levels were >82 dB(A around shovels. Noise levels on both sides of conveyor belts were in the range of 80–85 dB(A in Situations A and C whereas it was 85–90 dB(A in Situation B. Near crusher plants, it ranged from 80 to 90 dB(A in Situations A and C and between 85 and 95 dB(A in Situation B. In all situations, noise levels near residential areas exceeded the Central Pollution Control Board (CPCB limits, i.e., 55 dB(A. Conclusions: For all situations, predicted noise levels exceeded CPCB limits within the mine and nearby residential area. Residential areas near the crusher plants are vulnerable to increased noise propagation. It is recommended to put an acoustic barrier near the crusher plant to attenuate the noise propagation.

  9. Sequentially Adapted Parallel Feedforward Active Noise Control of Noisy Sinusoidal Signals

    Directory of Open Access Journals (Sweden)

    Govind Kannan

    2009-01-01

    Full Text Available A large class of acoustic noise sources has an underlying periodic process that generates a periodic noise component, and thus their acoustic noise can in general be modeled as the sum of a periodic signal and a randomly fluctuating signal (usually a broadband background noise. Active control of periodic noise (i.e., for a mixture of sinusoids is more effective than that of random noise. For mixtures of sinusoids in a background broadband random noise, conventional FXLMS-based single filter method does not reach the maximum achievable Noise Attenuation Level (NALmax⁡. In this paper, an alternative approach is taken and the idea of a parallel active noise control (ANC architecture for cancelling mixtures of periodic and random signals is presented. The proposed ANC system separates the noise into periodic and random components and generates corresponding antinoises via separate noise cancelling filters, and tends to reach NALmax⁡ consistently. The derivation of NALmax⁡ is presented. Both the separation and noise cancellation are based on adaptive filtering. Experimental results verify the analytical development by showing superior performance of the proposed method, over the single-filter approach, for several cases of sinusoids in white noise.

  10. Target detection under sea background using constructed biorthogonal wavelet

    Institute of Scientific and Technical Information of China (English)

    Peng Zhang; Jianxun Li

    2006-01-01

    A new technique is presented to detect targets under sea background. Focused on interested areas, the spatial and frequency distributions are first studied, then analytic expression of targets is set up by least square method (LSM). According to the shape, frequency, and analytic expression of targets, a matched biorthogonal wavelet is constructed to better enhance targets and eliminate noises. Results show the usefulness of this method for single frame detection (signal to noise ratio SNR ≥ 1.25), which provides a better performance than classic wavelets and morphological filtering.

  11. Spin Hall noise

    NARCIS (Netherlands)

    Kamra, A.; Witek, F.P.; Meyer, S.; Huebl, H.; Geprägs, S.; Gross, R.; Bauer, G.E.W.; Goennenwein, S.T.B.

    2014-01-01

    We measure the low-frequency thermal fluctuations of pure spin current in a platinum film deposited on yttrium iron garnet via the inverse spin Hall effect (ISHE)-mediated voltage noise as a function of the angle α between the magnetization and the transport direction. The results are consistent wit

  12. When noise becomes voice

    DEFF Research Database (Denmark)

    Veerasawmy, Rune; McCarthy, John

    2014-01-01

    space in competition with their rivals. The more noise and movement they make, the more screen real estate they gain. BannerBattle therefore enabled us to explore the emergence of imitative and at times inventive behavior in enriched crowd experience, by augmenting and supporting spectator performance...

  13. The Galker test of speech reception in noise

    DEFF Research Database (Denmark)

    Lauritsen, Maj-Britt Glenn; Söderström, Margareta; Kreiner, Svend;

    2016-01-01

    PURPOSE: We tested "the Galker test", a speech reception in noise test developed for primary care for Danish preschool children, to explore if the children's ability to hear and understand speech was associated with gender, age, middle ear status, and the level of background noise. METHODS......: The Galker test is a 35-item audio-visual, computerized word discrimination test in background noise. Included were 370 normally developed children attending day care center. The children were examined with the Galker test, tympanometry, audiometry, and the Reynell test of verbal comprehension. Parents...... to Reynell test scores (Gamma (G)=0.35), the children's age group (G=0.33), and the day care teachers' assessment of the children's vocabulary (G=0.26). CONCLUSIONS: The Galker test of speech reception in noise appears promising as an easy and quick tool for evaluating preschool children's understanding...

  14. JEM-X background models

    DEFF Research Database (Denmark)

    Huovelin, J.; Maisala, S.; Schultz, J.;

    2003-01-01

    revolution 41 of INTEGRAL. Total observing time used for the analysis was 216 502 s, with the average of 25 cps of background for each of the two JEM-X telescopes. JEM-X1 showed slightly higher average background intensity than JEM-X2. The detectors were stable during the long exposures, and weak orbital...... phase dependence in the background outside radiation belts was observed. The analysis yielded an average of 5 cps for the diffuse background, and 20 cps for the instrument background. The instrument background was found highly dependent on position, both for spectral shape and intensity. Diff use...... background was enhanced in the central area of a detector, and it decreased radially towards the edge, with a clear vignetting effect for both JEM-X units. The instrument background was weakest in the central area of a detector and showed a steep increase at the very edges of both JEM-X detectors, with...

  15. Destriping Cosmic Microwave Background Polarimeter data

    CERN Document Server

    Zonca, Andrea; Meinhold, Peter; Lubin, Philip

    2013-01-01

    Destriping is a well-established technique for removing low-frequency correlated noise from Cosmic Microwave Background (CMB) survey data. In this paper we present a destriping algorithm tailored to data from a polarimeter, i.e. an instrument where each channel independently measures the polarization of the input signal. We also describe a fully parallel implementation in Python released as Open Source software and analyze its results and performance on simulated datasets, both the design case of signal and correlated noise, and also with the addition of other systematic effects. Finally we apply the algorithm to 30 days of 40 GHz polarized microwave data gathered from the B-Machine experiment, developed at UCSB. The B-Machine data and destriped maps are publicly available. The purpose is the development of a scalable software tool to be applied to the upcoming 12 months of temperature and polarization data from LATTE (Low frequency All sky TemperaTure Experiment) at 8 GHz and to even larger datasets.

  16. Low-frequency noise in single electron tunneling transistor

    DEFF Research Database (Denmark)

    Tavkhelidze, A.N.; Mygind, Jesper

    1998-01-01

    The noise in current biased aluminium single electron tunneling (SET) transistors has been investigated in the frequency range of 5 mHz radiation and especially high energy...... photons emitted by the 4.2 K environment from reaching the sample, allows us to study a given background charge configuration for many hours below [approximate] 100 mK. The noise at relatively high frequencies originates from internal (presumably thermal equilibrium) charge fluctuations. For f >= 10 Hz......, we find the same input charge noise, typically QN = 5 × 10–4 e/Hz1/2 at 10 Hz, with and without the HF shielding. At lower frequencies, the noise is due to charge trapping, and the voltage noise pattern superimposed on the V(Vg) curve (voltage across transistor versus gate voltage) strongly depends...

  17. Noise and noise abatement in fans and blowers: A review

    Science.gov (United States)

    Neise, W.

    1980-03-01

    Noise generation and its reduction industrial fans (ventilators) is addressed. A review is given of the fan types commonly in use and their practical applications, the mechanisms of the aerodynamic noise generation in fans, theoretical and empirical prediction methods for fan noise, acoustic similarity laws, and noise reduction methods by means of the fan construction and fan operation. Measurement procedures are discussed with respect to the noise radiated from different parts of a fan, e.g. from the fan inlet or outlet, from the fan casing, from the fan as a whole, and to the noise radiated into ducts connected to the fan. Finally, considerations are made, for which classes of fans noise standards can be defined to characterize the noise emission of the various fan types.

  18. Tandem Cylinder Noise Predictions

    Science.gov (United States)

    Lockhard, David P.; Khorrami, Mehdi R.; CHoudhari, Meelan M.; Hutcheson, Florence V.; Brooks, Thomas F.; Stead, Daniel J.

    2007-01-01

    In an effort to better understand landing-gear noise sources, we have been examining a simplified configuration that still maintains some of the salient features of landing-gear flow fields. In particular, tandem cylinders have been studied because they model a variety of component level interactions. The present effort is directed at the case of two identical cylinders spatially separated in the streamwise direction by 3.7 diameters. Experimental measurements from the Basic Aerodynamic Research Tunnel (BART) and Quiet Flow Facility (QFF) at NASA Langley Research Center (LaRC) have provided steady surface pressures, detailed off-surface measurements of the flow field using Particle Image Velocimetry (PIV), hot-wire measurements in the wake of the rear cylinder, unsteady surface pressure data, and the radiated noise. The experiments were conducted at a Reynolds number of 166 105 based on the cylinder diameter. A trip was used on the upstream cylinder to insure a fully turbulent shedding process and simulate the effects of a high Reynolds number flow. The parallel computational effort uses the three-dimensional Navier-Stokes solver CFL3D with a hybrid, zonal turbulence model that turns off the turbulence production term everywhere except in a narrow ring surrounding solid surfaces. The current calculations further explore the influence of the grid resolution and spanwise extent on the flow and associated radiated noise. Extensive comparisons with the experimental data are used to assess the ability of the computations to simulate the details of the flow. The results show that the pressure fluctuations on the upstream cylinder, caused by vortex shedding, are smaller than those generated on the downstream cylinder by wake interaction. Consequently, the downstream cylinder dominates the noise radiation, producing an overall directivity pattern that is similar to that of an isolated cylinder. Only calculations based on the full length of the model span were able to

  19. Radioactive krypton background evaluation using atom counting

    International Nuclear Information System (INIS)

    The beta-decay of 85Kr is a significant radioactive background for experiments that use liquified noble gases to search for dark matter and measure the low-energy solar neutrino flux. While there are several proposed methods for reducing Kr levels in these experiments, an independent technique is needed for measuring very low Kr levels. By selectively exciting Kr atoms to a metastable state, capturing them in a magneto-optical trap (MOT), and detecting fluorescence from the trapped atoms, individual Kr atoms can be counted with a high signal-to-noise ratio. This approach could be used to ascertain Kr impurity levels in other noble gases, with an estimated sensitivity of 3x10-14

  20. GIS to Evaluate Road Traffic Noise in Makassar City, Indonesia

    OpenAIRE

    Hustim, Muralia; Fujimoto, Kazutoshi; Yasuhiro, Hiraguri

    2013-01-01

    In recent years, the increase of vehicle number in developing countries including Indonesia leads the rise of road traffic noise (RTN). Regarding this, the authors examine a guideline to find optimal solution for the RTN problem. To achieve this, an integrated noise-GIS (Geographic Information System) which predicts and evaluates the RTN is needed. On this background, this paper aims to establish a GIS applicable in Makassar City in Indonesia. This GIS is based on POEM, which has been develop...

  1. The effects of road traffic noise on mental performance

    OpenAIRE

    Iraj Alimohammadi; Raziyeh Soltani; Stephan Sandrock; Manouchehr Azkhosh; Mahmood Reza Gohari

    2013-01-01

    Background Noise is one of the more widespread pollutions of road transportation system, which can cause deterioration in performance. This experimental study was designed to assess the effect of road traffic noise on performance with regard to extra/introversion and sex of participants. The personality trait of extra/introversion has been remarked as relevant factor to mental performance. Results Thirty six (26 males and 10 females) medical sciences students of Tehran University participated...

  2. Shot-noise limited detection sensitivity in multiplex CARS microscopy

    OpenAIRE

    Müller, M; Schins, J.M.; Wurpel, G.W.H.

    2004-01-01

    In multiplex CARS microscopy the generated anti-Stokes signal is generated and detected simultaneously over a significant part of the vibrational spectrum. The signal-to-noise ratio of the thus detected spectra is limited only by shot-noise. This principle is demonstrated using a dilution series of 2-propanol in water. It is derived theoretically and shown experimentally that for low solute concentrations - in contrast to methods that suppress the non-resonant background - the CARS signal str...

  3. Laboratory Investigation of Noise-Canceling Headphones Utilizing ``Mr. Blockhead''

    Science.gov (United States)

    Koser, John

    2013-09-01

    While I was co-teaching an introductory course in musical acoustics a few years ago, our class investigated several pieces of equipment designed for audio purposes. One piece of such equipment was a pair of noise-canceling headphones. Our students were curious as to how these devices were in eliminating background noise and whether they indeed block low-frequency sounds as advertised.

  4. Detection of short transients in colored noise by multiresolution analysis

    OpenAIRE

    Stevens, John Davenport.

    2000-01-01

    Detecting short transients is a signal processing application that has a wide range of military uses. To be specific in Undersea Warfare, sensitive signal detection schemes can increase the effective range of active and passive sonar operations. Current research is being done to improve the capability of detecting short signals buried within background noise, particularly in Littoral waters. Starting with a colored noise model, this thesis will introduce two denoising methods based on multire...

  5. Noise synthesis for the Virtual Community Noise Simulator

    OpenAIRE

    Arntzen, M.

    2013-01-01

    Aircraft noise imposes restrictions on possible growth of airports. Noise mitigation measures can be based long-term predictive models but would benefit from high-fidelity simulation of the audible effects. To this end the NLR uses its Virtual Community Noise Simulator (VCNS). Several modelling steps and an application will be demonstrated in this article as to show the promising future of aircraft noise synthesis.

  6. Noise issues in Kanagawa Prefecture

    Science.gov (United States)

    Yokoshima, Shigenori; Tamura, Akihiro

    2001-05-01

    In Kanagawa Prefecture, bordering Tokyo Metropolis and the third most densely populated prefecture in Japan, various noises have caused serious problems in terms of living environment preservation and human health protection. This paper describes present states of noise issues in Kanagawa. Road traffic noise, remaining one of serious pollution issues, was monitored at a total 217 sites along trunk roads in Kanagawa from fiscal year 2000 to 2002. The percentage of the sites that achieve environmental quality standards for road traffic noise was approximately 20%. Noise caused by Tokaido Shinkansen trains, of which the total daily number is 287, also has negative impacts on inhabitants along the railway. As a result of the noise measurement from fiscal year 1994 to 2002, about 80% of the measurement sites exceeded environmental quality standards for Shinkansen railway noise during the years. In the areas surrounding the Atsugi Base, noise generated by training flights damagingly affects inhabitants' daily life. The number of complaints due to the noise was largest among noise issues. Moreover, neighborhood noises, noises emitted during the nighttime operation of bars, restaurants and shops, and noises produced by work in out-of-door yards have recently provoked social issues.

  7. 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,

  8. 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)…

  9. 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 harmfu

  10. Annoyance of low frequency noise and traffic noise

    DEFF Research Database (Denmark)

    Mortensen, Frank Rysgaard; Poulsen, Torben

    2000-01-01

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

  11. 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...

  12. Ultra-low noise mechanically cooled germanium detector

    Science.gov (United States)

    Barton, P.; Amman, M.; Martin, R.; Vetter, K.

    2016-03-01

    Low capacitance, large volume, high purity germanium (HPGe) radiation detectors have been successfully employed in low-background physics experiments. However, some physical processes may not be detectable with existing detectors whose energy thresholds are limited by electronic noise. In this paper, methods are presented which can lower the electronic noise of these detectors. Through ultra-low vibration mechanical cooling and wire bonding of a CMOS charge sensitive preamplifier to a sub-pF p-type point contact HPGe detector, we demonstrate electronic noise levels below 40 eV-FWHM.

  13. Ultra-Low Noise Mechanically Cooled Germanium Detector

    CERN Document Server

    Barton, Paul; Martin, Ryan; Vetter, Kai

    2015-01-01

    Low capacitance, large volume, high purity germanium (HPGe) radiation detectors have been successfully employed in low-background physics experiments. However, some physical processes may not be detectable with existing detectors whose energy thresholds are limited by electronic noise. In this paper, methods are presented which can lower the electronic noise of these detectors. Through ultra-low vibration mechanical cooling and wire bonding of a CMOS charge sensitive preamplifier to a sub-pF p-type point contact HPGe detector, we demonstrate electronic noise levels below 40 eV-FWHM.

  14. Does Masking Matter? Shipping Noise and Fish Vocalizations.

    Science.gov (United States)

    Neenan, Sarah T V; Piper, Rayner; White, Paul R; Kemp, Paul; Leighton, Timothy G; Shaw, Peter J

    2016-01-01

    Shipping creates large near-field background noises at levels similar to or higher than fish vocalizations and in the same critical bandwidths. This noise has the potential to "mask" biologically important signals and prevent fish from hearing them; any interference with the detection and recognition of sounds may impact fish survival. The Lombard effect, whereby vocalizations are altered to reduce or exclude masking effects, is an adaptation that has been observed in mammals and birds. Research is needed to establish whether the Lombard effect occurs in fish to gain a better understanding of the implications of noise pollution on fish populations. PMID:26611028

  15. Supergravity backgrounds and symmetry superalgebras

    CERN Document Server

    Ertem, Ümit

    2016-01-01

    We consider the bosonic sectors of supergravity theories in ten and eleven dimensions which correspond to the low energy limits of string theories and M-theory. The solutions of supergravity field equations are known as supergravity backgrounds and the number of preserved supersymmetries in those backgrounds are determined by Killing spinors. We provide some examples of supergravity backgrounds which preserve different fractions of supersymmetry. An important invariant for the characterization of supergravity backgrounds is their Killing superalgebras which are constructed out of Killing vectors and Killing spinors of the background. After constructing Killing superalgebras of some special supergravity backgrounds, we discuss about the possibilities of the extensions of these superalgebras to include the higher degree hidden symmetries of the background.

  16. Fast High-Quality Noise

    DEFF Research Database (Denmark)

    Frisvad, Jeppe Revall; Wyvill, Geoff

    2007-01-01

    , 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......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...... 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....

  17. Wind turbine noise source characterization

    International Nuclear Information System (INIS)

    Wind turbine noise is a function of many parameters. Aerodynamics noise is a direct function of the rotor characteristics and wind speed, which can change rapidly with time. Mechanical noise is primarily a function of electrical power output, but the radiation of such noise is highly modified by vibration behaviour within the turbine. An experiment has been performed to isolate the behaviour of the major WTG noise sources with respect to electrical power output and wind speed. Twelve ground based microphones equispaced around the turbine gave detailed noise directionality information. Additional instrumentation was added to allow the separation of aerodynamic and mechanical noise components. Noise was found to be very well correlated to electrical power output. (author)

  18. 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 ...

  19. How CANMET tests noise pollution

    Energy Technology Data Exchange (ETDEWEB)

    Savich, M.U.

    1983-07-01

    The paper describes a noise control program that CANMET has developed to protect miners from permanent hearing loss. Studies at a uranium mine at Elliot Lake were used to reach three objectives: first to identify main underground job categories by noise exposure index; second to measure cyclical noise; and third to establish the effectiveness of ear muffs used in mines. Some of the data obtained is included. Several recommendations for noise control are made.

  20. A low noise amplifier and its noise performances (Contract research)

    International Nuclear Information System (INIS)

    For development of two-dimensional position sensitive (2-D) neutron detectors with fast response and high spatial resolution, an ASIC with fast response and low noise performances is required. The MP8 and MP16, consisting of p-MOSFETs, with high gm and low noise have been proposed to develop the ASIC. In this paper a simple low noise amplifier (LNA) was designed and the noise power and the noise figure were analytically calculated. The results were also applied to LNAs using MP8 or MP16 configuration. The results showed that the MP8 and MP16 had enough performances for the ASIC. (author)

  1. Ex / Noise / CERN / Deerhoof

    CERN Multimedia

    CERN, SM18,

    2015-01-01

    Indie rockers Deerhoof battled with the noise of CERN’s magnet test facilities on 30 August 2015. The band visited CERN at the invitation of ATLAS physicist James Beacham, whose pilot project Ex/Noise/CERN collides experimental music artists with experimental particle physics. Credits: -Producer- CERN Video Productions James Beacham François Briard -Director- Noemi Caraban -Camera- Yann Krajewski Piotr Traczyk Noemi Caraban -Crane operator- Antonio Henrique Jorge-Costa -Live recording at CERN- Mixing at Rec studio/Geneva By Serge Morattel -Infography- Daniel Dominguez Noemi Caraban -Deerhoof- John Dieterich Satomi Matsuzaki Ed Rodriguez Greg Saunier w/Deron Pulley SPECIAL THANKS TO: Michal Strychalski Marta Bajko Maryline Charrondiere Luca Bottura Christian Giloux Rodrigue Faes Mariane Catallon Georgina Hobgen Hailey Reissman Marine Bass

  2. Noise in biology

    International Nuclear Information System (INIS)

    Noise permeates biology on all levels, from the most basic molecular, sub-cellular processes to the dynamics of tissues, organs, organisms and populations. The functional roles of noise in biological processes can vary greatly. Along with standard, entropy-increasing effects of producing random mutations, diversifying phenotypes in isogenic populations, limiting information capacity of signaling relays, it occasionally plays more surprising constructive roles by accelerating the pace of evolution, providing selective advantage in dynamic environments, enhancing intracellular transport of biomolecules and increasing information capacity of signaling pathways. This short review covers the recent progress in understanding mechanisms and effects of fluctuations in biological systems of different scales and the basic approaches to their mathematical modeling. (review article)

  3. Low-frequency noise complaints

    DEFF Research Database (Denmark)

    Pedersen, Christian Sejer; Møller, Henrik; Persson-Waye, Kerstin

    2006-01-01

    In Denmark and in other industrialized countries there are cases where people complain about annoying low-frequency or infrasonic noise in their homes. Besides noise annoyance people often report other adverse effects such as insomnia, headache, lack of concentration etc. In many cases the noise is...

  4. 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.

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

    Science.gov (United States)

    Salomons, Erik M; Janssen, Sabine A

    2011-06-01

    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 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. PMID:21776205

  6. Sounds Alive: A Noise Workbook.

    Science.gov (United States)

    Dickman, Donna McCord

    Sarah Screech, Danny Decibel, Sweetie Sound and Neil Noisy describe their experiences in the world of sound and noise to elementary students. Presented are their reports, games and charts which address sound measurement, the effects of noise on people, methods of noise control, and related areas. The workbook is intended to stimulate students'…

  7. Monte Carlo simulation for background study of geophysical inspection with cosmic-ray muons

    Science.gov (United States)

    Nishiyama, Ryuichi; Taketa, Akimichi; Miyamoto, Seigo; Kasahara, Katsuaki

    2016-08-01

    Several attempts have been made to obtain a radiographic image inside volcanoes using cosmic-ray muons (muography). Muography is expected to resolve highly heterogeneous density profiles near the surface of volcanoes. However, several prior works have failed to make clear observations due to contamination by background noise. The background contamination leads to an overestimation of the muon flux and consequently a significant underestimation of the density in the target mountains. To investigate the origin of the background noise, we performed a Monte Carlo simulation. The main components of the background noise in muography are found to be low-energy protons, electrons and muons in case of detectors without particle identification and with energy thresholds below 1 GeV. This result was confirmed by comparisons with actual observations of nuclear emulsions. This result will be useful for detector design in future works, and in addition some previous works of muography should be reviewed from the view point of background contamination.

  8. 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 ...

  9. 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

  10. Community response to noise

    OpenAIRE

    Takashi Yano; Truls Gjestland; Soogab Lee

    2012-01-01

    Activities from 2008 to 2011 by ICBEN community response to noise team were summarized. That is, individual community-based indexes such as community tolerance Level, Zuricher Fluglarm Index (ZFI) and Frankfurter Fluglarm Index (FFI/FNI) were newly proposed, differences in railway bonus between Europe and Asia were discussed by a Swedish survey, socio-acoustic surveys were reported from developing countries, and annoyance equivalents and dominant source models were proposed as the adequate co...

  11. Spin Hall noise

    OpenAIRE

    Kamra, A.; Witek, F.P.; Meyer, S.; Huebl, H.; Geprägs, S.; Gross, R.; Bauer, G. E. W.; Goennenwein, S. T. B.

    2014-01-01

    We measure the low-frequency thermal fluctuations of pure spin current in a Platinum film deposited on yttrium iron garnet via the inverse spin Hall effect (ISHE)-mediated voltage noise as a function of the angle $\\alpha$ between the magnetization and the transport direction. The results are consistent with the fluctuation dissipation theorem in terms of the recently discovered spin Hall magnetoresistance (SMR). We present a microscopic description of the $\\alpha$ dependence of the voltage no...

  12. Noise characterization for LISA

    OpenAIRE

    Sylvestre, Julien; Tinto, Massimo

    2003-01-01

    We consider the general problem of estimating the inflight LISA noise power spectra and cross-spectra, which are needed for detecting and estimating the gravitational wave signals present in the LISA data. For the LISA baseline design and in the long wavelength limit, we bound the error on all spectrum estimators that rely on the use of the fully symmetric Sagnac combination ($\\zeta$). This procedure avoids biases in the estimation that would otherwise be introduced by the presence of a stron...

  13. Probabilistic noise reduction

    OpenAIRE

    Hansen, James A.; Smith, Leonard A

    2011-01-01

    State estimation is an important factor in the production of accurate forecasts. Great effort isexpended in reducing the noise inherent in observations, to produce a ‘‘best’’ estimate of thetrue system state. But noisy observations necessitate a probabilistic, not a deterministic,approach to state estimation. A state’s probabilistic description is rarely Gaussian, and requiresinformation beyond variance magnitude; the correct distribution is restricted by the underlyingstructure of the system...

  14. Stochastic noise in translation

    OpenAIRE

    Stefaniuk, Adam; Racle, Julien; Hatzimanikatis, Vassily

    2011-01-01

    Translation lies at the heart of every living organism, it is the process synthesizing the proteins, a main component in the cells. Earlier studies have considered protein synthesis as mainly initiation limited, modeling it as a first-order reaction with respect to free ribosomes and mRNA. In such studies, the noise is therefore coming from initiation phase only. We have previously studied a continuous deterministic model for translation, taking into account the ribosome elongation and a poss...

  15. Sonic Crystal Noise Barriers

    OpenAIRE

    Chong, Yung

    2012-01-01

    An alternative road traffic noise barrier using an array of periodically arranged vertical cylinders known as a Sonic Crystal (SC) is investigated. As a result of multiple (Bragg) scattering, SCs exhibit a selective sound attenuation in frequency bands called band gaps or stop bands related to the spacing and size of the cylinders. Theoretical studies using Plane Wave Expansion (PWE), Multiple Scattering Theory (MST) and Finite Element Method (FEM) have enabled study of the performance of SC ...

  16. Dynamical decoupling noise spectroscopy

    OpenAIRE

    Alvarez, Gonzalo A.; Suter, Dieter

    2011-01-01

    Decoherence is one of the most important obstacles that must be overcome in quantum information processing. It depends on the qubit-environment coupling strength, but also on the spectral composition of the noise generated by the environment. If the spectral density is known, fighting the effect of decoherence can be made more effective. Applying sequences of inversion pulses to the qubit system, we generate effective filter functions that probe the environmental spectral density. Comparing d...

  17. Noise induced Hopf bifurcation

    OpenAIRE

    Shuda, I. A.; Borysov, S S; A.I. Olemskoi

    2008-01-01

    We consider effect of stochastic sources upon self-organization process being initiated with creation of the limit cycle induced by the Hopf bifurcation. General relations obtained are applied to the stochastic Lorenz system to show that departure from equilibrium steady state can destroy the limit cycle in dependence of relation between characteristic scales of temporal variation of principle variables. Noise induced resonance related to the limit cycle is found to appear if the fastest vari...

  18. Higher moments of noise

    OpenAIRE

    Reulet, Bertrand

    2005-01-01

    In this article we present simple approaches to the calculation of P(i) (the probability distribution of current fluctuations) in a tunnel junction, and to the effect of the environment on noise measurements in terms of the modification of P. We do not provide rigorous calculations, but simple considerations that bear the essential ingredients of the phenomena. We also discuss the effect of a finite measurement bandwidth. We report experimental results of the first measurement of the third mo...

  19. Extracting information from noise

    OpenAIRE

    Baptie, Brian

    2010-01-01

    Seismic waves created by sources such as wind, the ocean and human activity propagate inside the Earth all the time. Such waves are often regarded as ‘noise’ by seismologists, however, they travel through the Earth in exactly the same way as those waves from earthquakes. Recent advances in theory have shown that ambient noise recorded at two seismic stations can be combined to provide information about the properties of the Earth between the two stations. This is known as seism...

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

    Science.gov (United States)

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

    2014-03-01

    Speech perception depends on access to spectral and temporal acoustic cues. Temporal cues include slowly varying amplitude changes (i.e. temporal envelope, TE) and quickly varying amplitude changes associated with the center frequency of the auditory filter (i.e. temporal fine structure, TFS). This study quantifies the effects of TFS randomization through noise vocoding on the perception of speech quality by parametrically varying the amount of original TFS available above 1500Hz. The two research aims were: 1) to establish the role of TFS in quality perception, and 2) to determine if the role of TFS in quality perception differs between subjects with normal hearing and subjects with sensorineural hearing loss. Ratings were obtained from 20 subjects (10 with normal hearing and 10 with hearing loss) using an 11-point quality scale. Stimuli were processed in three different ways: 1) A 32-channel noise-excited vocoder with random envelope fluctuations in the noise carrier, 2) a 32-channel noise-excited vocoder with the noise-carrier envelope smoothed, and 3) removal of high-frequency bands. Stimuli were presented in quiet and in babble noise at 18dB and 12dB signal-to-noise ratios. TFS randomization had a measurable detrimental effect on quality ratings for speech in quiet and a smaller effect for speech in background babble. Subjects with normal hearing and subjects with sensorineural hearing loss provided similar quality ratings for noise-vocoded speech. PMID:24333929

  1. The Effect of Noise on Human Performance: A Clinical Trial

    Directory of Open Access Journals (Sweden)

    K Azam

    2013-04-01

    Full Text Available Background: Noise is defined as unwanted or meaningless sound that apart from auditory adverse health effects may distract attention from cues that are important for task performance. Human performance is influenced by many job-related factors and workplace conditions including noise level.Objective: To study the effect of noise on human performance.Methods: The participants included 40 healthy male university students. The experimental design consisted of 3 (sound pressure level x 3 (noise schedule x 2 (noise type factors. To investigate occupational skill performance, some specific test batteries were used: 1 steadiness test, 2 Minnesota manual dexterity test, 3 hand tool dexterity test, and 4 two-arm coordination test. Time duration of test completion was measured as speed response; to determine error response, the time taken during committing an error by participants while performing a task was measured.Results: Speed response obtained from the 4 tests in combined conditions of noise schedule, harmonic index, and sound pressure level was highest for (intermittent, treble, 95 dB, (continuous, treble, 95 dB, (continuous, treble, 85 dB and (intermittent, treble, 95 dB, respectively.Conclusion: Treble noise was found significant in reducing human performance; also, intermittent noise, especially at high pressure levels, was responsible for worsening environmental conditions during performing a task.

  2. Noise and mental performance: personality attributes and noise sensitivity.

    Science.gov (United States)

    Belojevic, G; Jakovljevic, B; Slepcevic, V

    2003-01-01

    The contradictory and confusing results in noise research on humans may partly be due to individual differences between the subjects participating in different studies. This review is based on a twelve year research on the role of neuroticism, extroversion and subjective noise sensitivity during mental work in noisy environment. Neurotic persons might show enhanced "arousability" i.e. their arousal level increases more in stress. Additional unfavorable factors for neurotics are worrying and anxiety, which might prevent them coping successfully with noise, or some other stressors during mental performance. In numerous experiments introverts have showed higher sensitivity to noise during mental performance compared to extroverts, while extroverts often cope with a boring task even by requesting short periods of noise during performance. Correlation analyses have regularly revealed a highly significant negative relation between extroversion and noise annoyance during mental processing. Numerous studies have shown that people with high noise sensitivity may be prevented from achieving the same work results as other people in noisy environment, thus leading to psychosomatic, neurotic or other difficulties. Positive relation between noise annoyance and subjective noise sensitivity might be very strong. Our results have shown, after matching with the results of other relevant studies, that more stable personality, with extroversive tendencies and with a relatively lower subjective noise sensitivity measured with standard questionnaires, may be expected to better adapt to noise during mental performance, compared to people with opposite personality traits. PMID:14965455

  3. Aircraft noise prediction

    Science.gov (United States)

    Filippone, Antonio

    2014-07-01

    This contribution addresses the state-of-the-art in the field of aircraft noise prediction, simulation and minimisation. The point of view taken in this context is that of comprehensive models that couple the various aircraft systems with the acoustic sources, the propagation and the flight trajectories. After an exhaustive review of the present predictive technologies in the relevant fields (airframe, propulsion, propagation, aircraft operations, trajectory optimisation), the paper addresses items for further research and development. Examples are shown for several airplanes, including the Airbus A319-100 (CFM engines), the Bombardier Dash8-Q400 (PW150 engines, Dowty R408 propellers) and the Boeing B737-800 (CFM engines). Predictions are done with the flight mechanics code FLIGHT. The transfer function between flight mechanics and the noise prediction is discussed in some details, along with the numerical procedures for validation and verification. Some code-to-code comparisons are shown. It is contended that the field of aircraft noise prediction has not yet reached a sufficient level of maturity. In particular, some parametric effects cannot be investigated, issues of accuracy are not currently addressed, and validation standards are still lacking.

  4. Noise Analysis of MAIA System and Possible Noise Suppression

    Directory of Open Access Journals (Sweden)

    J. Svihlik

    2011-04-01

    Full Text Available This paper is devoted to the noise analysis and noise suppression in a system for double station observation of the meteors now known as MAIA (Meteor Automatic Imager and Analyzer. The noise analysis is based on acquisition of testing video sequences in different light conditions and their further statistical evaluation. The main goal is to find a suitable noise model and subsequently determine if the noise is signal dependent or not. Noise and image model in the wavelet domain should be based on Gaussian mixture model (GMM or Generalized Laplacian Model (GLM and the model parameters should be estimated by moment method. Furthermore, noise should be modeled by GMM or GLM also in the space domain. GMM and GLM allow to model various types of probability density functions. Finally the advanced denoising algorithm using Bayesian estimator is applied and its performance is verified.

  5. The influence of jet engine noise on hearing of technical staff

    OpenAIRE

    Wiesław Konopka; Małgorzata Pawlaczyk-Łuszczyńska; Mariola Śliwińska-Kowalska

    2014-01-01

    Background: Due to high sound pressure levels (SPLs), noise produced by jet planes may be harmful to hearing of people working in their proximity. The aim of this study was to assess the effects of exposure to jet engine noise on technical staff hearing. Material and Methods: The study comprised 60 men, aged 24–50 years, employed in army as technical staff and exposed to jet engine noise for 6–20 years. The control group were 50 non-noise exposed males, aged 25–51 years. Exposure to noise emi...

  6. Military aviation noise:noise-induced hearing impairment and noise protection

    OpenAIRE

    Kuronen, P. (Pentti)

    2004-01-01

    Abstract This research on military aviation noise was conducted because the personnel working with military aircraft were concerned about noise induced hearing damage. In addition, comprehensive data on hearing impairments and occupational exposure of military pilots in the Finnish Air Force was not available. Moreover, data on the effects of overflight noise of military jets was necessary for the evaluation of noise induced hearing deteriorations of members of the ...

  7. Projected contributions of future wind farm development to community noise and annoyance levels in Ontario, Canada

    International Nuclear Information System (INIS)

    Wind turbines produce sound during their operation; therefore, jurisdictions around the world have developed regulations regarding the placement of electricity generating wind farms with the intent of preventing unacceptable levels of ‘community noise’ in their vicinity. However, as survey results indicate that the relationship between wind turbine noise and annoyance may differ from noise-annoyance relationships for other common noise sources (e.g., rail, traffic), there are concerns that the application of general noise guidelines for wind turbines may lead to unacceptably high levels of annoyance in communities. In this study, previously published survey results that quantified wind turbine noise and self-reported annoyance were applied to the predicted noise levels (from turbines and transformers) for over 8000 receptors in the vicinity of 13 planned wind power developments in the province of Ontario, Canada. The results of this analysis indicate that the current wind turbine noise restrictions in Ontario will limit community exposure to wind turbine related noise such that levels of annoyance are unlikely to exceed previously established background levels of noise-related annoyance from other common noise sources. This provides valuable context that should be considered by policy-makers when evaluating the potential impacts of wind turbine noise on the community. -- highlights: •Wind turbine noise-annoyance relationship used to predict annoyance in Ontario. •Noise annoyance predicted to be <8% for non-participants <1 km from turbines. •Predicted levels of wind turbine noise annoyance similar to that from traffic noise. •Wind turbine noise annoyance not expected to exceed existing background levels

  8. Background subtraction theory and practice

    CERN Document Server

    Elgammal, Ahmed

    2014-01-01

    Background subtraction is a widely used concept for detection of moving objects in videos. In the last two decades there has been a lot of development in designing algorithms for background subtraction, as well as wide use of these algorithms in various important applications, such as visual surveillance, sports video analysis, motion capture, etc. Various statistical approaches have been proposed to model scene backgrounds. The concept of background subtraction also has been extended to detect objects from videos captured from moving cameras. This book reviews the concept and practice of back

  9. Active control of the noise

    International Nuclear Information System (INIS)

    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

  10. Measurements techniques for transportation noise

    International Nuclear Information System (INIS)

    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)

  11. Measurements techniques for transportation noise

    Energy Technology Data Exchange (ETDEWEB)

    Brambilla, G

    2001-07-01

    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)

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

    OpenAIRE

    Sabine A. Janssen; Salomons, Erik M.

    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 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 o...

  13. Noise-induced coherent switch

    Institute of Scientific and Technical Information of China (English)

    YUAN ZhanJiang; ZHANG Jiadun; ZHOU TianShou

    2008-01-01

    Taking the famous genetic toggle switch as an example, we numerically investigated the effect of noise on bistability. We found that extrinsic noise resulting from stochastic fluctuations in synthesis and degradation rates and from the environmental fluctuation in gene regulatory processes can induce coherent switch, and that there is an optimal noise intensity such that the noise not only can induce this switch, but also can amplify a weak input signal. In addition, we found that the intrinsic noise introduced through the Poisson τ-leap algorithm cannot induce such a switch.

  14. Noise-induced coherent switch

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Taking the famous genetic toggle switch as an example,we numerically investigated the effect of noise on bistability.We found that extrinsic noise resulting from stochastic fluctuations in synthesis and degradation rates and from the environmental fluctuation in gene regulatory processes can induce coherent switch,and that there is an optimal noise intensity such that the noise not only can induce this switch,but also can amplify a weak input signal.In addition,we found that the intrinsic noise introduced through the Poisson τ-leap algorithm cannot induce such a switch.

  15. Noise-Mediated Generalized Synchronization

    Institute of Scientific and Technical Information of China (English)

    CHEN Yue-Hua; WU Zhi-Yuan; YANG Jun-Zhong

    2007-01-01

    @@ We investigate a drive-response system by considering the impacts of noise on generalized synchronization (GS).It is found that a small amount of noise can turn the system from desynchronization to the GS state in the resonant case no matter how noise is injected into the system. In the non-resonant case, noise with intensity in a certain range is helpful in building GS only when the noise is injected to the driving system. The mechanism behind the observed phenomena is discussed.

  16. The Noise Pollution Caused by Pneumatic Drills in City Services

    OpenAIRE

    Rostam Gol Mohammadi

    1999-01-01

    We designed this study to measure the Percussion caused by pneumatic drill( 32gram) which is used commonly in different in city services. this study have been performed in the summer of 1375 in Hamedan. The results demonstrated that the average background noise level (including environment and compressor) was 92.4 with standard deviation of 5.4 dBC, the average background noise level of the drills while working was 109.6 dBC with the standard deviation of about 2.2dBC and the average peaking ...

  17. Determination of FET noise parameters from 50 Ω noise figure measurements using a distributed noise model

    OpenAIRE

    Maya, M.C.; A. Lazaro; Pradell, L.

    2002-01-01

    A method for measuring FET noise parameters is presented. It is based on the determination of a distributed noise model from 50 Ω noise figure measurements without needing a tuner, and taking into account the propagation effects along device electrodes. Experimental results up to 40 GHz are given.

  18. Search for Higgs bosons in 2 lepton events and validation of a background noise detector in the DELPHI experiment; Recherche de bosons de higgs neutres dans les evenements a deux leptons isoles a LEP2 et mise au point d'un detecteur de controle du bruit de fond dans l'experience DELPHI

    Energy Technology Data Exchange (ETDEWEB)

    Lethuillier, M. [CEA/Saclay, Dept. d' Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l' Instrumentation Associee (DAPNIA), 91 - Gif-sur-Yvette (France)]|[Paris-7 Univ., 75 (France)

    1999-04-01

    This thesis presents two studies made within the DELPHI experiment in the context of the energy rise of the LEP collider. The first study concerns the setting up of a silicon plate detector that allows a continuous measurement of the background generated by the beams, particularly synchrotron radiation, the intensity of which increases strongly with the beam energy. This silicon monitor ensures a better safety of the more fragile DELPHI sub-detectors, especially the Time Projection Chamber, and gives a very precise measurement of the time of flight and energy of particles (2.1 ns and 3.6 keV resolution), thus allowing to identify the machine elements from which the background originates. The second study is devoted to the search for a neutral Higgs boson, produced in association with a Z boson decaying into an electron or a muon pair; we have searched for Higgs boson decays in b quarks, {tau} leptons or into invisible decay products as it is predicted by some supersymmetry scenarios. No signal has been observed in the 54 and 158 pb{sup -1} data recorded at {radical}s=183 and 189 GeV. Combining this result with those from other search channels, the hypothesis for a standard Higgs boson with a mass less than 94.5 GeV/c{sup 2} can be excluded at more than 95 % confidence level. In the frame of the Minimal Supersymmetric Model, this limit becomes 82.4 GeV/c{sup 2}, independently of the free parameter tan{beta}. Finally, as far as invisible decays are concerned, the limit becomes 90.2 GeV/c{sup 2}, independently of the branching ratio into invisible decay products. (author)

  19. Proceedings of noise-con 91

    International Nuclear Information System (INIS)

    This volume covers the following topics related to noise control: control of mine ventilation fans; physical phenomena; gas turbine exhaust system silencing; computer models for estimating electric utility environmental noise; noise from rotary coal car unloading; noise analysis

  20. Hanford Site background: Part 1, Soil background for nonradioactive analytes

    International Nuclear Information System (INIS)

    The determination of soil background is one of the most important activities supporting environmental restoration and waste management on the Hanford Site. Background compositions serve as the basis for identifying soil contamination, and also as a baseline in risk assessment processes used to determine soil cleanup and treatment levels. These uses of soil background require an understanding of the extent to which analytes of concern occur naturally in the soils. This report documents the results of sampling and analysis activities designed to characterize the composition of soil background at the Hanford Site, and to evaluate the feasibility for use as Sitewide background. The compositions of naturally occurring soils in the vadose Zone have been-determined for-nonradioactive inorganic and organic analytes and related physical properties. These results confirm that a Sitewide approach to the characterization of soil background is technically sound and is a viable alternative to the determination and use of numerous local or area backgrounds that yield inconsistent definitions of contamination. Sitewide soil background consists of several types of data and is appropriate for use in identifying contamination in all soils in the vadose zone on the Hanford Site. The natural concentrations of nearly every inorganic analyte extend to levels that exceed calculated health-based cleanup limits. The levels of most inorganic analytes, however, are well below these health-based limits. The highest measured background concentrations occur in three volumetrically minor soil types, the most important of which are topsoils adjacent to the Columbia River that are rich in organic carbon. No organic analyte levels above detection were found in any of the soil samples

  1. The association of noise sensitivity with music listening, training, and aptitude.

    Science.gov (United States)

    Kliuchko, Marina; Heinonen-Guzejev, Marja; Monacis, Lucia; Gold, Benjamin P; Heikkilä, Kauko V; Spinosa, Vittoria; Tervaniemi, Mari; Brattico, Elvira

    2015-01-01

    After intensive, long-term musical training, the auditory system of a musician is specifically tuned to perceive musical sounds. We wished to find out whether a musician's auditory system also develops increased sensitivity to any sound of everyday life, experiencing them as noise. For this purpose, an online survey, including questionnaires on noise sensitivity, musical background, and listening tests for assessing musical aptitude, was administered to 197 participants in Finland and Italy. Subjective noise sensitivity (assessed with the Weinstein's Noise Sensitivity Scale) was analyzed for associations with musicianship, musical aptitude, weekly time spent listening to music, and the importance of music in each person's life (or music importance). Subjects were divided into three groups according to their musical expertise: Nonmusicians (N = 103), amateur musicians (N = 44), and professional musicians (N = 50). The results showed that noise sensitivity did not depend on musical expertise or performance on musicality tests or the amount of active (attentive) listening to music. In contrast, it was associated with daily passive listening to music, so that individuals with higher noise sensitivity spent less time in passive (background) listening to music than those with lower sensitivity to noise. Furthermore, noise-sensitive respondents rated music as less important in their life than did individuals with lower sensitivity to noise. The results demonstrate that the special sensitivity of the auditory system derived from musical training does not lead to increased irritability from unwanted sounds. However, the disposition to tolerate contingent musical backgrounds in everyday life depends on the individual's noise sensitivity. PMID:26356378

  2. Background reduction in cryogenic detectors

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Daniel A.; /Fermilab

    2005-04-01

    This paper discusses the background reduction and rejection strategy of the Cryogenic Dark Matter Search (CDMS) experiment. Recent measurements of background levels from CDMS II at Soudan are presented, along with estimates for future improvements in sensitivity expected for a proposed SuperCDMS experiment at SNOLAB.

  3. Children of ethnic minority backgrounds

    DEFF Research Database (Denmark)

    Johansen, Stine Liv

    2010-01-01

    Children of ethnic minority background balance their everyday life between a cultural background rooted in their ethnic origin and a daily life in day care, schools and with peers that is founded in a majority culture. This means, among other things, that they often will have access to different ...

  4. Stochastic Background from Coalescences of NS-NS Binaries

    CERN Document Server

    Regimbau, T

    2006-01-01

    In this work, numerical simulations were used to investigate the gravitational stochastic background produced by coalescences occurring up to $z \\sim 5$ of double neutron star systems. The cosmic coalescence rate was derived from Monte Carlo methods using the probability distributions for forming a massive binary and to occur a coalescence in a given redshift. A truly continuous background is produced by events located only beyond the critical redshift $z_* = 0.23$. Events occurring in the redshift interval $0.027noise, while those arising closer than $z = 0.027$ produce a shot noise. The gravitational density parameter $\\Omega_{gw}$ for the continuous background reaches a maximum around 670 Hz with an amplitude of $1.1\\times 10^{-9}$, while the "popcorn" noise has an amplitude about one order of magnitude higher and the maximum occurs around a frequency of 1.2 kHz. The signal is below the sensitivity of the first generation of detectors but could be detectable by the...

  5. Theory And Working Of Noise And Vibration

    International Nuclear Information System (INIS)

    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.

  6. Wind turbines. Unsteady aerodynamics and inflow noise

    Energy Technology Data Exchange (ETDEWEB)

    Riget Broe, B.

    2009-12-15

    Aerodynamical noise from wind turbines due to atmospheric turbulence has the highest emphasis in semi-empirical models. However it is an open question whether inflow noise has a high emphasis. This illustrates the need to investigate and improve the semi-empirical model for noise due to atmospheric turbulence. Three different aerodynamical models are investigated in order to estimate the lift fluctuations due to unsteady aerodynamics. Two of these models are investigated to find the unsteady lift distribution or pressure difference as function of chordwise position on the aerofoil. An acoustic model is investigated using a model for the lift distribution as input. The two models for lift distribution are used in the acoustic model. One of the models for lift distribution is for completely anisotropic turbulence and the other for perfectly isotropic turbulence, and so is also the corresponding models for the lift fluctuations derived from the models for lift distribution. The models for lift distribution and lift are compared with pressure data which are obtained by microphones placed flush with the surface of an aerofoil. The pressure data are from two experiments in a wind tunnel, one experiment with a NACA0015 profile and a second with a NACA63415 profile. The turbulence is measured by a triple wired hotwire instrument in the experiment with a NACA0015 profile. Comparison of the aerodynamical models with data shows that the models capture the general characteristics of the measurements, but the data are hampered by background noise from the fan propellers in the wind tunnel. The measurements are in between the completely anisotropic turbulent model and the perfectly isotropic turbulent model. This indicates that the models capture the aerodynamics well. Thus the measurements suggest that the noise due to atmospheric turbulence can be described and modeled by the two models for lift distribution. It was not possible to test the acoustical model by the measurements

  7. Noise and Vibrations Measurements. External noise and vibrations measurements for offshore SODAR application

    International Nuclear Information System (INIS)

    The partners in the WISE project investigate whether application of the SODAR (sonic detection and ranging) measurement technique in wind energy experimental work is feasible as a replacement for cup anemometers, wind direction sensors and tall meteorological masts. In Work Package 2 of the WISE project extensive controlled experiments with the SODAR are performed. For example SODAR measurements are compared with measurements from nearby masts and different brands of SODARs are compared. Part of the work package is the measurement of vibration and noise on an offshore SODAR system. The results of these measurements are presented in this report. ECN performed measurements at an offshore location to investigate the influence of noise and vibrations on the performance of a MiniSODAR measurement system. The aim of the measurements is to quantify the effect of these external noise and vibrations disturbances on the MiniSODAR's performance. Measurements on an identical SODAR system onshore are carried out to compare the disturbances of offshore and onshore external conditions. The effect of background noise on SODAR operation has clearly been established in literature. Therefore, measurements have been performed only to establish the absolute sound pressure levels. This is done at the Measuring Platform Noordwijk (MPN) located in the North Sea, nine kilometres out of the coast at Noordwijk, The Netherlands, and at two locations onshore. At the MPN-platform, the SODAR has been moved from the middle deck to the upper deck to diminish the influence of the diesel generator needed for the electric powering of the island. Although the absolute sound pressure level became higher at the new location, this level became lower at the most important frequencies inside the SODAR, due to the use of absorbing foam. With regards to the sound pressure level the move improved the situation. The sound pressure levels measured offshore were 6 to 15 dB higher than for the two locations

  8. Contribution to the G{sup 0} experiment about parity violation: calculation and simulation of radiative corrections, study of the background noise; Contribution a l'experience G{sup 0} de violation de la parite: calcul et simulation des corrections radiatives et etude de bruit de fond

    Energy Technology Data Exchange (ETDEWEB)

    Guler, H

    2003-12-01

    In the framework of quantum chromodynamics, the nucleon is made of three valence quarks surrounded by a sea of gluons and quark-antiquark pairs. Only the only lightest quarks (u, d and s) contribute significantly to the nucleon properties. In G{sup 0} we use the property of weak interaction to violate parity symmetry, in order to determine separately the contributions of the three types of quarks to nucleon form factors. The experiment, which takes place at Thomas Jefferson laboratory (USA), aims at measuring parity violation asymmetry in electron-proton scattering. By doing several measurements at different momentum squared of the exchanged photons and for different kinematics (forward angle when the proton is detected and backward angle it will be the electron) will permit to determine separately strange quarks electric and magnetic contributions to nucleon form factors. To extract an asymmetry with small errors, it is necessary to correct all the beam parameters, and to have high enough counting rates in detectors. A special electronics was developed to treat information coming from 16 scintillator pairs for each of the 8 sectors of the G{sup 0} spectrometer. A complete calculation of radiative corrections has been done and Monte Carlo simulations with the GEANT program has permitted to determine the shape of the experimental spectra including inelastic background. This work will allow to do a comparison between experimental data and theoretical calculations based on the Standard Model. (author)

  9. Progress in understanding the diffuse UV cosmic background

    Science.gov (United States)

    Henry, Richard Conn

    I report on progress in my ongoing work with Professor Jayant Murthy concerning the origin and nature of the diffuse ultraviolet background radiation over the sky. We have obtained and are reducing a vast trove of Voyager ultraviolet spectrometer observations of the diffuse background shortward of Lalpha , including for the first time measurements made from the outermost regions of the solar system, where noise from solar-system scattered (and then grating-scattered) solar Lalpha is lowest. Also, we have obtained and are investigating the complete set of GALEX observations of the diffuse ultraviolet background longward of Lalpha . Preliminary investigation appears to confirm that longward of Lalpha there exists a component of the diffuse ultraviolet background that is not dust-scattered starlight.

  10. Progress in Understanding the Diffuse UV Cosmic Background

    CERN Document Server

    Henry, Richard Conn

    2012-01-01

    I report on progress in my ongoing work with Professor Jayant Murthy concerning the origin and nature of the diffuse ultraviolet background radiation over the sky. We have obtained and are reducing a vast trove of Voyager ultraviolet spectrometer observations of the diffuse background shortward of Lyman alpha, including for the first time measurements made from the outermost regions of the solar system, where noise from solar-system scattered (and then grating-scattered) solar Lyman alpha is lowest. Also, we have obtained and are investigating the complete set of GALEX observations of the diffuse ultraviolet background longward of Lyman alpha. Preliminary investigation appears to confirm that longward of Lyman alpha there exists a component of the diffuse ultraviolet background that is not dust-scattered starlight.

  11. A method of complex background estimation in astronomical images

    CERN Document Server

    Popowicz, Adam

    2016-01-01

    In this paper, we present a novel approach to the estimation of strongly varying backgrounds in astronomical images by means of small objects removal and subsequent missing pixels interpolation. The method is based on the analysis of a pixel local neighborhood and utilizes the morphological distance transform. In contrast to popular background estimation techniques, our algorithm allows for accurate extraction of complex structures, like galaxies or nebulae. Moreover, it does not require multiple tuning parameters, since it relies on physical properties of CCD image sensors - the gain and the read-out noise characteristics. The comparison with other widely used background estimators revealed higher accuracy of the proposed technique. The superiority of the novel method is especially significant for the most challenging fluctuating backgrounds. The size of filtered out objects is tunable, therefore the algorithm may eliminate a wide range of foreground structures, including the dark current impulses, cosmic ra...

  12. Noise hazard course

    CERN Multimedia

    2003-01-01

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

  13. Noise hazard course

    CERN Multimedia

    2003-01-01

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

  14. Quantum Noise Locking

    OpenAIRE

    McKenzie, Kirk; Mikhailov, Eugeniy; Goda, Keisuke; Lam, Ping Koy; Grosse, Nicolai; Gray, Malcolm B.; Mavalvala, Nergis; McClelland, David E.

    2005-01-01

    Quantum optical states which have no coherent amplitude, such as squeezed vacuum states, can not rely on standard readout techniques to generate error signals for control of the quadrature phase. Here we investigate the use of asymmetry in the quadrature variances to obtain a phase-sensitive readout and to lock the phase of a squeezed vacuum state, a technique which we call noise locking (NL). We carry out a theoretical derivation of the NL error signal and the associated stability of the squ...

  15. Low noise constant current source for bias dependent noise measurements

    International Nuclear Information System (INIS)

    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.

  16. Cosmic microwave background polarization results from QUIET

    International Nuclear Information System (INIS)

    Despite the success of precision cosmology, cosmologists cannot fully explain the initial conditions of the Universe. Inflation, an exponential expansion in the first ∼ 10-36 s, is a promising potential explanation. A generic prediction of inflation is odd-parity (B-mode) polarization in the cosmic microwave background (CMB). Q/U Imaging Experiment (QUIET) aimed at limiting or detecting this polarization. We built a pseudo-correlation microwave polarimeter as an array of mass-produced modules in the focal plane of a 1.4 m telescope. We used rotation around the absorbing ground screen, a new time-stream double-demodulation technique, and optimized optics in the design to reduce instrumental polarization. We observed with this instrument at the Atacama Plateau in Chile between October 2008 and December 2010. This paper describes the analysis and results of these observations from one of 2 parallel pipelines. We developed noise modeling, filtering and data selection following a blind-analysis strategy. Central to this strategy was a suite of null test, each motivated by a possible instrumental problem or systematic effect. We evaluated the systematic errors in the blind stage of the analysis before the result was known. We calculated the CMB power spectra using a pseudo-Cl cross-correlation technique that suppressed contamination and made the result insensitive to noise bias. We measured the first 3 peaks of the E-mode spectrum at high significance and limited B-mode polarization. We measured the CMB polarization power at 25 ≤ l ≤ 975. We found no statistically significant deviation from ΛCDM model, and our results are consistent with zero BB and EB power. Systematic errors were well below our B-mode polarization limits. This systematic-error reduction was a strong demonstration of technology for application in more sensitive, next generation CMB experiments. (author)

  17. Noise pollution filters bird communities based on vocal frequency.

    Directory of Open Access Journals (Sweden)

    Clinton D Francis

    Full Text Available BACKGROUND: Human-generated noise pollution now permeates natural habitats worldwide, presenting evolutionarily novel acoustic conditions unprecedented to most landscapes. These acoustics not only harm humans, but threaten wildlife, and especially birds, via changes to species densities, foraging behavior, reproductive success, and predator-prey interactions. Explanations for negative effects of noise on birds include disruption of acoustic communication through energetic masking, potentially forcing species that rely upon acoustic communication to abandon otherwise suitable areas. However, this hypothesis has not been adequately tested because confounding stimuli often co-vary with noise and are difficult to separate from noise exposure. METHODOLOGY/PRINCIPAL FINDINGS: Using a natural experiment that controls for confounding stimuli, we evaluate whether species vocal features or urban-tolerance classifications explain their responses to noise measured through habitat use. Two data sets representing nesting and abundance responses reveal that noise filters bird communities nonrandomly. Signal duration and urban tolerance failed to explain species-specific responses, but birds with low-frequency signals that are more susceptible to masking from noise avoided noisy areas and birds with higher frequency vocalizations remained. Signal frequency was also negatively correlated with body mass, suggesting that larger birds may be more sensitive to noise due to the link between body size and vocal frequency. CONCLUSIONS/SIGNIFICANCE: Our findings suggest that acoustic masking by noise may be a strong selective force shaping the ecology of birds worldwide. Larger birds with lower frequency signals may be excluded from noisy areas, whereas smaller species persist via transmission of higher frequency signals. We discuss our findings as they relate to interspecific relationships among body size, vocal amplitude and frequency and suggest that they are

  18. Occupational noise in printing companies.

    Science.gov (United States)

    Mihailovic, Aleksandra; Grujic, Selena D; Kiurski, Jelena; Krstic, Jelena; Oros, Ivana; Kovacevic, Ilija

    2011-10-01

    The extent of noise in five printing companies in Novi Sad, Serbia, was determined using TES-1358A Sound Analyzer with RS-232 Interface. The data on equivalent A-level (dBA), as well as, maximum and minimum sound pressure levels were collected. It was found that folders and offset printing units are the predominant noise sources, with the average L (eq) levels of 87.66 and 82.7 dBA, respectively. Forty percent of the machines produced noise levels above the limiting threshold level of 85 dBA, allowed by law. The noise in all printing companies was dominated by higher frequency noise, and the maximum level mostly appeared at 4,000 Hz. For offset printing machines and folders, the means of L (eq) levels exceeded the permissible levels given by NR-80 curve at higher frequencies. There are no published studies of occupational noise and hearing impairment of workers exposed to hazardous noise in printing industry in Serbia. More extensive studies are needed to determine the exact impact of noise on the workers. Technical and organizational measures in order to control noise and prevent noise exposure, and general hearing conservation program to protect workers, should be introduced in printing industry. PMID:21161679

  19. Monitoring of Noise During Ganeshotsav

    Directory of Open Access Journals (Sweden)

    Mrs. P. Saler

    2011-09-01

    Full Text Available Sound is a form of energy emitted by a vibrating body causing change in pressure of the surrounding elastic medium through which energy is transmitted. Noise has been defined as unwanted sound. Noise is a disturbance to the human environment which is escalating at a high rate. There are numerous effects of noise on human and environment due to the increase in noise pollution slowly, insensibly; we seem to accept noise and the physiological and psychological deterioration that accompanies it as an inevitable part of our lives. Althoughattempts have been made to regulate noise pollution by setting standards for some of the major sources of noise, we often are unable to monitor them. One such source of noise in India is celebration of festival and especially in Maharashtra, the biggest festival- Ganeshostav. The way noise levels are increasing year by year during this festival, it seems we enjoy these sounds, though it has harmful effects on Human Health and Environment. This paper focuses on study of noise pollution during Ganesh Festival and also its other causes and effects.

  20. Noise Level of Hospital Environment

    Directory of Open Access Journals (Sweden)

    Suphi Vehid

    2011-08-01

    Full Text Available Aim: Noise pollution is one of the important problems among the environmental pollution. In this present study we tried to show that the problem of noise at hospital is still exceeding and investigate the sources of noise that annoyed the patients mostly. We measured the sound levels randomly selected in wards and asked the patients the causes of the noise annoying the patients mostly. Material and Methods:Noise level were measured during August 2009 by Testo 816 Sound Lever Meter in Cerrahpasa Medical Faculty. Total of the readings were taken in the day time between 09.00 am and 15.00 pm with three minutes intervals Results: Daily sound level is differing between 45 dBA and 61 dBA. Measured sound level at the beginning time was significantly lower in Neurology and Otorhinolaryngology wards compare to others. During the day time maximum Leq was observed in Physical Therapy and Rehabilitation ward (61 dBA. Telephone bells and conversations, Talking in corridors and water running from faucet declared as a most frequent of noise source by the patients. Conclusion: Activities of medical and non-medical staff are the common source of noise which suggests the noise pollution is mostly “manmade”. In order to solve the noise problem at hospitals there is great need to staff education, administrative rules and may be first of all national guidelines for hospital noise. [TAF Prev Med Bull 2011; 10(4.000: 409-414

  1. Characterization of typical chemical background interferences in atmospheric pressure ionization liquid chromatography-mass spectrometry

    NARCIS (Netherlands)

    Guo, Xinghua; Bruins, Andries P.; Covey, Thomas R.

    2006-01-01

    The structures and origins of typical chemical background noise ions in positive atmospheric pressure ionization liquid chromatography/mass spectrometry (API LC/MS) are investigated and summarized in this study. This was done by classifying chemical background ions using precursor and product ion sc

  2. Cosmological flux noise and measured noise power spectra in SQUIDs

    OpenAIRE

    Beck, Christian

    2014-01-01

    The understanding of the origin of $1/f$ magnetic flux noise commonly observed in superconducting devices such as SQUIDS and $q$-bits is still a major unsolved puzzle. Here we discuss the possibility that a significant part of the observed low-frequency flux noise measured in these devices is ultimately seeded by cosmological fluctuations. We consider a theory where a primordial flux noise field left over in unchanged form from an early inflationary or quantum gravity epoch of the universe in...

  3. Effects of noise on the distribution of the cell surface glycoconjugates in the developing mouse spiral ganglion

    OpenAIRE

    Talaei T; Monsefi M; Vojdani Z; Dehghani F; Arab M R

    2007-01-01

    Background: Some pregnant women are exposed to occupational noise, a risk factor for the development of the auditory system. The auditory system is one of the areas in embryonic development in which noise might induce aberrant development. Noise can change the gene expression pattern of an embryo and thereby modify the physiology of the auditory system. Therefore, noise can change the molecular structure of the developing ear. One of the critical molecules involved in development of auditory ...

  4. Development of Active Noise Control System for Quieting Transformer Noise

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Bok Kyu; Song, Seik Young; Choi, Huo Yul [Korea Electric Power Research Institute, Taejon (Korea, Republic of); Yun, Dae Hea; Lee, Hyuk Jae [Korea Electrotechnology Research Institute, Changwon (Korea, Republic of)

    1997-12-31

    The passive noise control technique made use of sound-absorbing or soundproofing materials, so it required a large area and high cost for installation and had a drawback of poor performance at low frequency. Compared to this, the Active Noise Control attenuates noise sound pressure by using secondary source which has same performance ay low-frequency. Furthermore, it is able to save space and expenses. - research on adaptive algorithms - evaluation of global attenuation of the control - computer simulation - real-time Active Noise Control System Hardware Implementation - ANC system setting in the noisy area.

  5. Pulsed noise analysis system

    Energy Technology Data Exchange (ETDEWEB)

    Barsanti, M.L. [Naval Research Lab., Washington, DC (United States); Smutek, L.S. [Mission Research Corp., Newington, VA (United States); Armstrong, C.M. [Northrop Grumman Corp., Rolling Meadows, IL (United States)

    1995-12-31

    NRL studies of various microwave and millimeter wave amplifiers and the need to know and understand their characteristics have led to the development of a pulsed noise analysis system. This system is capable of measuring amplitude, phase, and total spectra of two signals simultaneously. It can also measure am/pm conversion, group or phase delay and linearity, and phase and amplitude jitter. The system downconverts the signal to be analyzed and then digitizes the intermediate frequency. The digitized sample is transferred to a personal computer equipped with LabVIEW, where all further processing and analysis takes place. It is digitally demodulated into I and Q channels which can then be separated into amplitude and phase information. Discrete Fourier Transforms are used to display the spectral information. Measurements have been performed on both conventional linear beam devices such as commercially available TWT and klystron amplifiers. As well as two gyro-devices, the NRL gyroklystron and gyrotwystron amplifiers. These measurements were expanded to include noise power dependency on various tube parameters such as beam current and alpha. The results of the analysis will be used as a basis for modifying the gyrotwystron amplifier to improve its operating characteristics.

  6. Noise storm coordinated observations

    International Nuclear Information System (INIS)

    The usually accepted bipolar model of noise storm centers is irrelevant for the present observations. An alternative model has been proposed in which the different sources of a noise storm center are located in different flux tubes connecting active regions with their surroundings. Radio emission is observed from the wide, descending branch of the flux tubes, opposite to the flaring site. The relation between the sense of circular polarization of the radio emission and the magnetic polarity, has been more precisely defined. The radiation is in the ordinary mode with respect to the underlying large scale photospheric magnetic polarity. Thus the ''irregular'' polarity of noice storm center ''B'' is explained. As regards center ''C'', one should note that although the observed radio emission is polarized in the ordinary mode with respect to the leading spot of region HR 17653, center ''C'' is not situated in flux tubes originating from the leading part of this region according to the proposed model. Rather, the radio sources are located in the wide and descending part of flux tubes connecting a large, quiet area of south magnetic polarity with the following part of the region HR 17653 (of north magnetic polarity). Thus it is the polarity of the extended area which determines the polarization of the radio emission. The observed polarization should result rather from the emission process than from complicated conditions of propagation for the radio waves

  7. Low-noise SQUID

    Science.gov (United States)

    Dantsker, Eugene; Clarke, John

    2000-01-01

    The present invention comprises a high-transition-temperature superconducting device having low-magnitude low-frequency noise-characteristics in magnetic fields comprising superconducting films wherein the films have a width that is less than or equal to a critical width, w.sub.C, which depends on an ambient magnetic field. For operation in the Earth's magnetic field, the critical width is about 6 micrometers (.mu.m). When made with film widths of about 4 .mu.m an inventive high transition-temperature, superconducting quantum interference device (SQUID) excluded magnetic flux vortices up to a threshold ambient magnetic field of about 100 microTesla (.mu.T). SQUIDs were fabricated having several different film strip patterns. When the film strip width was kept at about 4 .mu.m, the SQUIDs exhibited essentially no increase in low-frequency noise, even when cooled in static magnetic fields of magnitude up to 100 .mu.T. Furthermore, the mutual inductance between the inventive devices and a seven-turn spiral coil was at least 85% of that for inductive coupling to a conventional SQUID.

  8. Origin of the chemical noise in ambient mass spectrometry

    International Nuclear Information System (INIS)

    The instrumental background of ambient mass spectrometry, (API-MS) is analyzed and the possible potential origins of the background noise is identified. According to the mass spectra obtained using the API-MS instruments by different manufacturers, the characteristic fragment ions all indicated that the background noise are resulted from the phthalates such as diethyl phthalate (DEP), dibutyl phthalate (DBP), benzyl butyl phthalate (BBP), bis (2-ethylhexyl) phthalate (DEHP), and silicones such as decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6). These chemicals are probably released from the polymeric materials used in the ionization sources, such as O-type sealing ring etc. In addition, the instrumental background has to be considered especially during the analysis of phthalate and peptide compounds. (authors)

  9. Epidemiology of noise-induced tinnitus and the attitudes and beliefs towards noise and hearing protection in adolescents.

    Directory of Open Access Journals (Sweden)

    Annick Gilles

    Full Text Available BACKGROUND AND OBJECTIVES: Previous research showed an increase of noise-induced symptoms in adolescents. Permanent tinnitus as a consequence of loud music exposure is usually considered as noise-induced damage. The objective was to perform an epidemiological study in order to obtain prevalence data of permanent noise-induced tinnitus as well as temporary tinnitus following noise exposure in a young population. In addition the attitudes and beliefs towards noise and hearing protection were evaluated in order to explain the use/non-use of hearing protection in a young population. METHODS: A questionnaire was completed by 3892 high school students (mean age: 16.64 years old, SD: 1.29 years. The prevalence of temporary and permanent tinnitus was assessed. In addition the 'Youth Attitudes to Noise Scale' and the 'Beliefs About Hearing Protection and Hearing Loss' were used in order to assess the attitudes and beliefs towards noise and hearing protection respectively. RESULTS: The prevalence of temporary noise-induced tinnitus and permanent tinnitus in high school students was respectively 74.9% and 18.3%. An increasing prevalence of temporary tinnitus with age was present. Most students had a 'neutral attitude' towards loud music and the use of hearing protection was minimal (4.7%. The limited use of hearing protection is explained by a logistic regression analysis showing the relations between certain parameters and the use of hearing protection. CONCLUSIONS: Despite the very high prevalence of tinnitus in such a young population, the rate of hearing protection use and the knowledge about the risks of loud music is extremely low. Future preventive campaigns should focus more on tinnitus as a warning signal for noise-induced damage and emphasize that also temporary symptoms can result in permanent noise-induced damage.

  10. An Effective History-based Background Extraction System

    Directory of Open Access Journals (Sweden)

    Fatimah Khalid

    2012-01-01

    Full Text Available Problem statement: In many visions-based surveillance systems, the first step is accomplished by detecting moving objects resulted from subtraction of the current captured frame from the extracted background. So, the results of these systems mainly depend on the accuracy of the background image. Approach: In this study, a proposed background extraction system is presented to model the background using a simple method, to initialize the model, to extract the moving objects and to construct the final background. Our model saves the history of each pixel separately. It uses the saved information to extract the background using a probability-based method. It updates the history of the pixel consequently and according to the value of that pixel in the current captured image. Results: Results of the experiments certify that not only the quality of the final extracted background is the best between four recently re-implemented methods, but also the time consumption of the extraction is acceptable. Conclusion: Since History-based methods use temporal information extracted from the several previous frames, they are less sensitive to noise and sudden changes for extracting the background image.

  11. Adaptive noise estimation and suppression for improving microseismic event detection

    Science.gov (United States)

    Mousavi, S. Mostafa; Langston, Charles A.

    2016-09-01

    Microseismic data recorded by surface arrays are often strongly contaminated by unwanted noise. This background noise makes the detection of small magnitude events difficult. A noise level estimation and noise reduction algorithm is presented for microseismic data analysis based upon minimally controlled recursive averaging and neighborhood shrinkage estimators. The method might not be compared with more sophisticated and computationally expensive denoising algorithm in terms of preserving detailed features of seismic signal. However, it is fast and data-driven and can be applied in real-time processing of continuous data for event detection purposes. Results from application of this algorithm to synthetic and real seismic data show that it holds a great promise for improving microseismic event detection.

  12. Generalized Background-Field Method

    CERN Document Server

    Feng, Y J

    1997-01-01

    The graphical method discussed previously can be used to create new gauges not reachable by the path-integral formalism. By this means a new gauge is designed for more efficient two-loop QCD calculations. It is related to but simpler than the ordinary background-field gauge, in that even the triple-gluon vertices for internal lines contain only four terms, not the usual six. This reduction simplifies the calculation inspite of the necessity to include other vertices for compensation. Like the ordinary background-field gauge, this generalized background-field gauge also preserves gauge invariance of the external particles. As a check of the result and an illustration for the reduction in labour, an explicit calculation of the two-loop QCD 45% of computation compared to the ordinary background-field gauge.

  13. The Cosmic Background Radiation, 1997

    CERN Document Server

    Smoot, G F; Smoot, George; Scott, Douglas

    1997-01-01

    We summarise the current status of cosmic microwave background spectrum and anisotropy measurements, and their theoretical interpretation. This is the update of the mini-review for the 1997 web-version of the Review of Particle Properties.

  14. Geometrodynamics on a background spacetime

    CERN Document Server

    Papadopoulos, P P; Papadopoulos, Philippos; Sopuerta, Carlos F.

    2001-01-01

    The formulation of the initial value problem for the Einstein equations is at the heart of obtaining interesting new solutions using numerical relativity and still very much under theoretical and applied scrutiny. We develop a specialised background geometry approach, for systems where there is non-trivial a priori knowledge about the spacetime under study. The background three-geometry and associated connection are used to express the ADM evolution equations in terms of physical non-linear deviations from that background. Expressing the equations in first order form leads naturally to a system closely linked to the Einstein-Christoffel system, introduced by Anderson and York, and sharing its hyperbolicity properties. The background metric approach can drastically alter the source structure of the equations, and we present an argument as to why this is likely to be numerically advantageous.

  15. Measurement of MRI scanner noise

    International Nuclear Information System (INIS)

    The present paper describes a simple method for the analysis of MRI scanner noise. Besides the heating of body tissue by strong RF radiation and the formation of circular currents in the body induced bey switching field gradients, a noise level of more than 100 dB(A) during the measurement belongs to the potential risks of MRI [1,2]. This risk is of particular concern for staff and accompanying persons who remain close to the scanner for different reasons (e.g., monitoring of anesthetized patients, reassuring of children). For this reason, and given the scanty information on noise provided in the manuals of the scanners, it is useful to quantify the noise level more exactly. This applies also to the evaluation of different sound-reducing methods for the patient. This presents the results of noise level measurements in the tomograph and in its surrounding, with and without noise reduction by headphones. (orig.)

  16. Noise Considerations in Resistance Bridges

    DEFF Research Database (Denmark)

    Diamond, Joseph M.

    1963-01-01

    thermometry, where the noise in the unknown resistor will predominate strongly. An impedance step-up device (transformer or tuned circuit) is valuable in raising the bridge signal and noise level above the noise of the first amplifier tube. However, as the step-up ratio is increased, two counterfactors appear......, namely, noise in the loss resistance of the step-up device, and grid current noise. There is therefore an optimum step-up ratio, which has been found. The step-up device is permitted to have a different temperature from the unknown and standard resistors, to evaluate the advantage of cooling it....... With certain assumptions about the noise and grid current of the first tube it is found that the equivalent temperature of a unity ratio (Mueller) bridge used for liquid helium measurements may be 400°K....

  17. Single-electron thermal noise

    International Nuclear Information System (INIS)

    We report the observation of thermal noise in the motion of single electrons in an ultimately small dynamic random access memory (DRAM). The nanometer-scale transistors that compose the DRAM resolve the thermal noise in single-electron motion. A complete set of fundamental tests conducted on this single-electron thermal noise shows that the noise perfectly follows all the aspects predicted by statistical mechanics, which include the occupation probability, the law of equipartition, a detailed balance, and the law of kT/C. In addition, the counting statistics on the directional motion (i.e., the current) of the single-electron thermal noise indicate that the individual electron motion follows the Poisson process, as it does in shot noise. (papers)

  18. Aircraft noise and birth weight

    Energy Technology Data Exchange (ETDEWEB)

    Knipschild, P.; Meijer, H.; Salle, H.

    1981-05-01

    Data from six infant welfare centres in the vicinity of Amsterdam airport were analysed. Birth weights of 902 infants were related to aircraft noise levels to which the mother was exposed in pregnancy. The analysis was restricted to deliveries in hospital, single births and mothers aged 20-34 years. In high noise areas the mean birth weight was 69 g lower than in low noise areas. Of the infants in high noise areas 24% had a birth weight less than 3000 g, compared with 18% in low noise areas. In the analysis the effect of sex of the infant, birth order and to some extent socio-economic status were taken into account. An effect of smoking seemed unlikely. The results, together with existing knowledge, give some suggestion that aircraft noise can decrease birth weight.

  19. QED_2 in Curved Backgrounds

    OpenAIRE

    Ghosh, Amit

    1996-01-01

    Here we discuss the two dimensional quantum electrodynamics in curved space-time, especially in the background of some black holes. We first show the existence of some new quantum mechanical solution which has interesting properties. Then for some special black holes we discuss the fermion-black hole scattering problem. The issue of confinement is intimately connected with these solutions and we also comment on this in this background. Finally, the entanglement entropy and the Hawking radiati...

  20. Backgrounds in AFP Detector Estimation

    CERN Document Server

    Huang, Yicong

    2016-01-01

    The ATLAS Forward Proton (AFP) detectors aim to measure protons that are scattered in the ATLAS interaction point under very small angles ($90-160 \\mu rad$). The diffractive protons detected by the AFP may be accompanied by beam halo. This report presents an estimation of the beam halo backgrounds in the AFP using low pile-up data, and position distributions of the backgrounds in the AFP.

  1. The Supernova Relic Neutrino Background

    OpenAIRE

    Kaplinghat, M.; Steigman, G.; Walker, T. P.

    1999-01-01

    An upper bound to the supernova relic neutrino background from all past Type II supernovae is obtained using observations of the Universal metal enrichment history. We show that an unambiguous detection of these relic neutrinos by the Super-Kamiokande detector is unlikely. We also analyze the event rate in the Sudbury Neutrino Observatory (where coincident neutrons from anti-nu_e + D --> n + n + e+ might enhance background rejection), and arrive at the same conclusion. If the relic neutrino f...

  2. Advantages of Binaural Amplification to Acceptable Noise Level of Directional Hearing Aid Users

    OpenAIRE

    Kim, Ja-Hee; Lee, Jae Hee; Lee, Ho-Ki

    2014-01-01

    Objectives The goal of the present study was to examine whether Acceptable Noise Levels (ANLs) would be lower (greater acceptance of noise) in binaural listening than in monaural listening condition and also whether meaningfulness of background speech noise would affect ANLs for directional microphone hearing aid users. In addition, any relationships between the individual binaural benefits on ANLs and the individuals' demographic information were investigated. Methods Fourteen hearing aid us...

  3. Associations between Nighttime Traffic Noise and Sleep: The Finnish Public Sector Study

    OpenAIRE

    Halonen, Jaana I; Vahtera, Jussi; Stansfeld, Stephen; Yli-Tuomi, Tarja; Salo, Paula; Pentti, Jaana; Kivimäki, Mika; Lanki, Timo

    2012-01-01

    Background: Associations between traffic noise and sleep problems have been detected in experimental studies, but population-level evidence is scarce. Objectives: We studied the relationship between the levels of nighttime traffic noise and sleep disturbances and identified vulnerable population groups. Methods: Noise levels of nighttime–outdoor traffic were modeled based on the traffic intensities in the cities of Helsinki and Vantaa, Finland. In these cities, 7,019 public sector employees (...

  4. Acceptable noise level with Danish, Swedish, and non-semantic speech materials.

    OpenAIRE

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

    2012-01-01

    Objective: Acceptable noise level (ANL) has been established as a method to quantify the acceptance of background noise while listening to speech presented at the most comfortable level. The aim of the present study was to generate Danish, Swedish, and a non-semantic version of the ANL test and investigate normal-hearing Danish and Swedish subjects' performance on these tests. Design: ANL was measured using Danish and Swedish running speech with two different noises: Speech-weighted ampli...

  5. Effects of Occupational Noise Exposure on 24-Hour Ambulatory Vascular Properties in Male Workers

    OpenAIRE

    Chang, Ta-Yuan; Su, Ta-Chen; Lin, Shou-Yu; Jain, Ruei-Man; Chan, Chang-Chuan

    2007-01-01

    Background Epidemiologic studies have demonstrated that occupational noise exposure is associated with hypertension, but the related mechanism in vascular structural changes is unclear. Objective This panel study aimed to investigate effects of occupational noise exposure on ambulatory vascular structural properties in male workers. Methods We recruited 20 volunteers and divided them into a high-noise–exposure group of 15 and a low-noise–exposure group of 5 based on environmental noise measur...

  6. Noise-induced hearing loss

    OpenAIRE

    Mariola Sliwinska-Kowalska; Adrian Davis

    2012-01-01

    Noise-induced hearing loss (NIHL) still remains a problem in developed countries, despite reduced occupational noise exposure, strict standards for hearing protection and extensive public health awareness campaigns. Therefore NIHL continues to be the focus of noise research activities. This paper summarizes progress achieved recently in our knowledge of NIHL. It includes papers published between the years 2008-2011 (in English), which were identified by a literature search of accessible medic...

  7. Aeroacoustic Prediction and Noise Reduction

    OpenAIRE

    Delfs, Jan Werner

    2011-01-01

    An overview is given about aeroacoustic prediction and noise reduction technology from the field of aircraft noise. The simulation philosophy of the prediction methods is related to real world application, i.e. high Reynolds number flows, typical for aircraft. Noise reduction concepts are studied in two ways i) through a silent by design approach and b) by add-on treatments for existing aircraft components. Challenges are identified for future research.

  8. Challenges in Aircraft Noise Prediction

    OpenAIRE

    Filippone A

    2014-01-01

    This contribution addresses the problem of aircraft noise prediction using theoretical methods. The problem is set in context with the needs at several levels to produce noise characterisation from commercial aircraft powered by gas turbine engines. We describe very briefly the computational model (whilst referring the reader to the appropriate literature), and provide examples of noise predictions and comparisons with measured data, where possible. We focus on the issue of stochastic analysi...

  9. Noise in the nervous system

    OpenAIRE

    Faisal, A. Aldo; Selen, Luc P.J.; Wolpert, Daniel M

    2008-01-01

    Random disturbances of signals, termed ‘noise’, pose a fundamental problem for information processing and affect all aspects of nervous-system function. However, the nature, amount and impact of noise in the nervous system have only recently been addressed in a quantitative manner. Experimental and computational methods have shown that multiple noise sources contribute to cellular and behavioural trial-to-trial variability. We review the sources of noise in the nervous system, from the molecu...

  10. Noise and Quality of Life

    OpenAIRE

    Seidman, Michael D.; Standring, Robert T.

    2010-01-01

    Noise is defined as an unwanted sound or a combination of sounds that has adverse effects on health. These effects can manifest in the form of physiologic damage or psychological harm through a variety of mechanisms. Chronic noise exposure can cause permanent threshold shifts and loss of hearing in specific frequency ranges. Noise induced hearing loss (NIHL) is thought to be one of the major causes of preventable hearing loss. Approximately 10 million adults and 5.2 million children in the US...

  11. The Noise Pollution Caused by Pneumatic Drills in City Services

    Directory of Open Access Journals (Sweden)

    Rostam Gol Mohammadi

    1999-03-01

    Full Text Available We designed this study to measure the Percussion caused by pneumatic drill( 32gram which is used commonly in different in city services. this study have been performed in the summer of 1375 in Hamedan. The results demonstrated that the average background noise level (including environment and compressor was 92.4 with standard deviation of 5.4 dBC, the average background noise level of the drills while working was 109.6 dBC with the standard deviation of about 2.2dBC and the average peaking factor was 18.6 with a standard deviation of 3.7dBC. the average background noise level of the drills while working in a distance of 5m, 10m and 20m from the source respectively were 98.6 dBA(with a standard deviation of 2.8dBA, 91.5dBA(with a standard deviation of2.6dBA and 86.8dBA with a standard deviation of 2.8dBA.Based on the obtained results and the potential effects of exposure to noise which mainly can be summarized to damage to auditory system, interference with the communication skills, neural excitation, Hypertension and tachycardia the side effects of noise should be taken in to account seriously.Based on the mounting evidences regarding the adverse impact of working in the noisy environment and the damaging consequences of living in such atmospheres and the findings of the current study which confirms that the noise exposure level is more than allowed limit, the health of the workers and citizens is threaded by the noise pollution factors mentioned in the current study and serious considerations should be taken in to account.

  12. Noise Reduction Using mel-Scale Spectral Subtraction with Perceptually Defined Subtraction Parameters- A New Scheme

    Directory of Open Access Journals (Sweden)

    Ch.V.Rama Rao

    2011-03-01

    Full Text Available The noise signal does not affect uniformly the speech signal over the whole spectrum isn the case ofcolored noise. In order to deal with speech improvement in such situations a new spectral subtractionalgorithm is proposed for reducing colored noise from noise corrupted speech. The spectrum is dividedinto frequency sub-bands based on a nonlinear multiband bark scale. For each sub-band, the noisecorrupted speech power in past and present time frames is compared to statistics of the noise power toimprove the determination of the presence or absence of speech. During the subtraction process, a largerproportion of noise is removed from sub-bands that do not contain speech. For sub-bands that containspeech, a function is developed which allows for the removal of less noise during relatively low amplitudespeech and more noise during relatively high amplitude speech .Further the performance of the spectralsubtraction is improved by formulating process without neglecting the cross correlation between the speechsignal and background noise. Residual noise can be masked by exploiting the masking properties of thehuman auditory system. In the proposed method subtraction parameters are adaptively adjusted usingnoise masking threshold. A psychoacoustically motivated weighting filter was included to eliminateresidual musical noise. Experimental results show that the algorithm removes more colored noise withoutremoving the relatively low amplitude speech at the beginning and ending of words.

  13. PREDICTION OF AIRCRAFT NOISE LEVELS

    Science.gov (United States)

    Clark, B. J.

    1994-01-01

    Methods developed at the NASA Lewis Research Center for predicting the noise contributions from various aircraft noise sources have been incorporated into a computer program for predicting aircraft noise levels either in flight or in ground test. The noise sources accounted for include fan inlet and exhaust, jet, flap (for powered lift), core (combustor), turbine, and airframe. Noise propagation corrections are available in the program for atmospheric attenuation, ground reflections, extra ground attenuation, and shielding. The capacity to solve the geometrical relationships between an aircraft in flight and an observer on the ground has been included in the program to make it useful in evaluating noise estimates and footprints for various proposed engine installations. The program contains two main routines for employing the noise prediction routines. The first main routine consists of a procedure to calculate at various observer stations the time history of the noise from an aircraft flying at a specified set of speeds, orientations, and space coordinates. The various components of the noise are computed by the program. For each individual source, the noise levels are free field with no corrections for propagation losses other than spherical divergence. The total spectra may then be corrected for the usual effects of atmospheric attenuation, extra ground attenuation, ground reflection, and aircraft shielding. Next, the corresponding values of overall sound pressure level, perceived noise level, and tone-weighted perceived noise level are calculated. From the time history at each point, true effective perceived noise levels are calculated. Thus, values of effective perceived noise levels, maximum perceived noise levels, and tone-weighted perceived noise levels are found for a grid of specified points on the ground. The second main routine is designed to give the usual format of one-third octave sound pressure level values at a fixed radius for a number of user

  14. Noise management of industrial parks

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-07-01

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

  15. Impulse Detectors for Noised Sequences

    Directory of Open Access Journals (Sweden)

    R. Lukac

    2001-06-01

    Full Text Available This paper is focused on a problem of impulse detection in thedynamic image environments corrupted by impulse noise. Using a proposedarchitecture that includes an impulse detector and the median filter,the effective methods can be designed. Thus, the image points areclassified into two classes such as a class of noise free samples and aclass of noised image points. In the case of impulse detection theestimate is performed by a median filter whereas a noise free sample ispassed on the output without the change i.e. system works as anidentity filter.

  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. Monte Carlo-based Noise Compensation in Coil Intensity Corrected Endorectal MRI

    CERN Document Server

    Lui, Dorothy; Haider, Masoom; Wong, Alexander

    2015-01-01

    Background: Prostate cancer is one of the most common forms of cancer found in males making early diagnosis important. Magnetic resonance imaging (MRI) has been useful in visualizing and localizing tumor candidates and with the use of endorectal coils (ERC), the signal-to-noise ratio (SNR) can be improved. The coils introduce intensity inhomogeneities and the surface coil intensity correction built into MRI scanners is used to reduce these inhomogeneities. However, the correction typically performed at the MRI scanner level leads to noise amplification and noise level variations. Methods: In this study, we introduce a new Monte Carlo-based noise compensation approach for coil intensity corrected endorectal MRI which allows for effective noise compensation and preservation of details within the prostate. The approach accounts for the ERC SNR profile via a spatially-adaptive noise model for correcting non-stationary noise variations. Such a method is useful particularly for improving the image quality of coil i...

  18. Comparative study of the effects of occupational exposure to infrasound and low frequency noise with those of audible noise

    Directory of Open Access Journals (Sweden)

    Krystyna Pawlas

    2014-03-01

    Full Text Available Background. The study aimed to compare effects of occupational exposure to low frequency noise (LFN in comparison with those of audible noise (AN. Material and methods. Three groups of 307 workers (I – exposed to LFN, II – exposed to audible noise – AN, and III- controls were examined. Results. Blood pressure and other biochemical parameters were worse in the group exposed. All parameters of hearing were worse in the AN group in comparison with LFN one in whole range of frequency. The same trends were found in posturography. Conclusions. The results of the study showed that audible noise is more hazardous than LFN. The results did not support thesis on vibroacoustic disease.

  19. Recent developments in firearms noise and hearing conservation: hearing protection fit testing,noise measurement and hearing surveillance

    Directory of Open Access Journals (Sweden)

    David McBride

    2013-01-01

    Full Text Available Background Noise induced hearing loss (NIHL continues to be a prevalent problem in Military Service. Purpose To assess the ‘SureFire’ earplug, a Hearing Protective Device (HPD, within the context of a hearing conservation programme. Methods The ‘VeriPro’ system was used to test the HPD attenuation, with Otoacoustic emission (OAE ‘base-line’ hearing tests. Noise exposure was measured during test firing, and a post exposure OAE test was carried out to measure any deterioration in hearing due to excess noise exposure. Results Better attenuation was achieved in right ears. The HPDs were rated to reduce the noise by at least 15 dB in 84% of those exposed, the actual attenuation lying in the range between 8.4 and 23.6 dBA. The median noise level was 110 dBA. The OAE testing did not show any significant before and after differences. Discussion. Some individuals achieved good HPD fit, some quite poor. The average noise levels received were excessive, but the daily noise dose was within acceptable limits because of the short duration of exposure, possibly explaining the non-significant differences in OAEs. We recommend that individuals should only use HPDs which are ‘fit proven’. Additional testing under more typical conditions with a larger group is required, but OAEs show promise as a practical monitoring tool.

  20. Improvements to background level of the low background HPGe setup

    International Nuclear Information System (INIS)

    A low background HPGe counting setup has been installed at TIFR. The detector, shielded with low activity Pb and Cu shield, has been extensively used for material screening for the TIN. TIN detector (The INdia-based TIN detector). It is proposed to use this setup for the search of rare decay processes like double beta decay (DBD) to the excited states of the daughter nuclei where T1/2 > 1018 years. To enhance the sensitivity of measurement, the background levels of the detector has been further improved by an addition of an active cosmic muon veto system in the FPGA based DAQ system