WorldWideScience

Sample records for background noise

  1. Pump cavitation background noise

    International Nuclear Information System (INIS)

    Cha, Y.S.

    1976-01-01

    Cavitation is defined as the growth and collapse of cavities associated with the change in pressure in contrast to the case of boiling where change in temperature is the dominating factor. It is commonly accepted that cavitation inception occurs when the minimum pressure in a system reaches the vapor pressure corresponding to the local temperatures of the liquid. The foregoing statement is, in fact, another way of defining incipient boiling which is usually defined as the condition where the temperature reaches the saturation temperature corresponding to the system pressure. Therefore, there is no difference between cavitation and boiling since both are associated with the growth and collapse of bubbles in a liquid. Cavitation noise may not be avoidable for an LMFBR primary pump under normal operating conditions, and will be present as background during boiling detection by acoustic methods

  2. Effects of background noise on total noise annoyance

    Science.gov (United States)

    Willshire, K. F.

    1987-01-01

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

  3. Speech recognition in natural background noise.

    Directory of Open Access Journals (Sweden)

    Julien Meyer

    Full Text Available 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 listener-to-speaker distance in a typical low-level natural background noise. The noise was combined with the simple spherical amplitude attenuation due to distance, basically changing the signal-to-noise ratio (SNR. Therefore, our study draws attention to some of the most basic environmental constraints that have pervaded spoken communication throughout human history. We evaluated the ability of native French participants to recognize French monosyllabic words (spoken at 65.3 dB(A, reference at 1 meter at distances between 11 to 33 meters, which corresponded to the SNRs most revealing of the progressive effect of the selected natural noise (-8.8 dB to -18.4 dB. Our results showed that in such conditions, identity of vowels is mostly preserved, with the striking peculiarity of the absence of confusion in vowels. The results also confirmed the functional role of consonants during lexical identification. The extensive analysis of recognition scores, confusion patterns and associated acoustic cues revealed that sonorant, sibilant and burst properties were the most important parameters influencing phoneme recognition. . Altogether these analyses allowed us to extract a resistance scale from consonant recognition scores. We also identified specific perceptual consonant confusion groups depending of the place in the words (onset vs. coda. Finally our data suggested that listeners may access some acoustic cues of the CV transition, opening interesting perspectives for

  4. Effects of a traffic noise background on judgements of aircraft noise

    Science.gov (United States)

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

    1974-01-01

    A study was conducted in which subjects judged aircraft noises in the presence of road traffic background noise. Two different techniques for presenting the background noises were evaluated. For one technique, the background noise was continuous over the whole of a test session. For the other, the background noise was changed with each aircraft noise. A range of aircraft noise levels and traffic noise levels were presented to simulate typical indoor levels.

  5. 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.

  6. 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

  7. Interdependent processing and encoding of speech and concurrent background noise.

    Science.gov (United States)

    Cooper, Angela; Brouwer, Susanne; Bradlow, Ann R

    2015-05-01

    Speech processing can often take place in adverse listening conditions that involve the mixing of speech and background noise. In this study, we investigated processing dependencies between background noise and indexical speech features, using a speeded classification paradigm (Garner, 1974; Exp. 1), and whether background noise is encoded and represented in memory for spoken words in a continuous recognition memory paradigm (Exp. 2). Whether or not the noise spectrally overlapped with the speech signal was also manipulated. The results of Experiment 1 indicated that background noise and indexical features of speech (gender, talker identity) cannot be completely segregated during processing, even when the two auditory streams are spectrally nonoverlapping. Perceptual interference was asymmetric, whereby irrelevant indexical feature variation in the speech signal slowed noise classification to a greater extent than irrelevant noise variation slowed speech classification. This asymmetry may stem from the fact that speech features have greater functional relevance to listeners, and are thus more difficult to selectively ignore than background noise. Experiment 2 revealed that a recognition cost for words embedded in different types of background noise on the first and second occurrences only emerged when the noise and the speech signal were spectrally overlapping. Together, these data suggest integral processing of speech and background noise, modulated by the level of processing and the spectral separation of the speech and noise.

  8. 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...

  9. 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 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 situations involve modulated noise. The investigation was carried out by testing two groups of older adults...... with similar degrees of mild-­‐to-­‐moderate sensorineural loss but different working memory abilities. The two groups were tested in their ability to understand a speech signal presented within a modulated background noise, processed with slow and fast compression. The extent of background noise modulation...

  10. The Effect of Background Noise on Intelligibility of Dysphonic Speech

    Science.gov (United States)

    Ishikawa, Keiko; Boyce, Suzanne; Kelchner, Lisa; Powell, Maria Golla; Schieve, Heidi; de Alarcon, Alessandro; Khosla, Sid

    2017-01-01

    Purpose: The aim of this study is to determine the effect of background noise on the intelligibility of dysphonic speech and to examine the relationship between intelligibility in noise and an acoustic measure of dysphonia--cepstral peak prominence (CPP). Method: A study of speech perception was conducted using speech samples from 6 adult speakers…

  11. Seismic Background Noise Analysis of BRTR (PS-43) Array

    Science.gov (United States)

    Ezgi Bakir, Mahmure; Meral Ozel, Nurcan; Umut Semin, Korhan

    2015-04-01

    The seismic background noise variation of BRTR array, composed of two sub arrays located in Ankara and in Ankara-Keskin, has been investigated by calculating Power Spectral Density and Probability Density Functions for seasonal and diurnal noise variations between 2005 and 2011. PSDs were computed within the frequency range of 100 s - 10 Hz. The results show us a little change in noise conditions in terms of time and location. Especially, noise level changes were observed at 3-5 Hz in diurnal variations at Keskin array and there is a 5-7 dB difference in day and night time in cultural noise band (1-10 Hz). On the other hand, noise levels of medium period array is high in 1-2 Hz frequency rather than short period array. High noise levels were observed in daily working times when we compare it to night-time in cultural noise band. The seasonal background noise variation at both sites also shows very similar properties to each other. Since these stations are borehole instruments and away from the coasts, we saw a small change in noise levels caused by microseism. Comparison between Keskin short period array and Ankara medium period array show us Keskin array is quiter than Ankara array.

  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.

    Science.gov (United States)

    Guthrie, O'neil W; Wong, Brian A; McInturf, Shawn M; Reboulet, James E; Ortiz, Pedro A; Mattie, David R

    2016-01-01

    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. Thresholding of auditory cortical representation by background noise

    Science.gov (United States)

    Liang, Feixue; Bai, Lin; Tao, Huizhong W.; Zhang, Li I.; Xiao, Zhongju

    2014-01-01

    It is generally thought that background noise can mask auditory information. However, how the noise specifically transforms neuronal auditory processing in a level-dependent manner remains to be carefully determined. Here, with in vivo loose-patch cell-attached recordings in layer 4 of the rat primary auditory cortex (A1), we systematically examined how continuous wideband noise of different levels affected receptive field properties of individual neurons. We found that the background noise, when above a certain critical/effective level, resulted in an elevation of intensity threshold for tone-evoked responses. This increase of threshold was linearly dependent on the noise intensity above the critical level. As such, the tonal receptive field (TRF) of individual neurons was translated upward as an entirety toward high intensities along the intensity domain. This resulted in preserved preferred characteristic frequency (CF) and the overall shape of TRF, but reduced frequency responding range and an enhanced frequency selectivity for the same stimulus intensity. Such translational effects on intensity threshold were observed in both excitatory and fast-spiking inhibitory neurons, as well as in both monotonic and nonmonotonic (intensity-tuned) A1 neurons. Our results suggest that in a noise background, fundamental auditory representations are modulated through a background level-dependent linear shifting along intensity domain, which is equivalent to reducing stimulus intensity. PMID:25426029

  16. The impact of different background noises on the Production Effect.

    Science.gov (United States)

    Mama, Yaniv; Fostick, Leah; Icht, Michal

    2018-04-01

    The presence of background noise has been previously shown to disrupt cognitive performance, especially memory. The amount of interference is derived from the acoustic characteristics of the noise; energetic vs. informational, steady-state vs. fluctuating. However, the literature is inconsistent concerning the effects of different types of noise on long-term memory free recall. In the present study, we tested the impact of different noises on recall of items that were learned under two conditions - silent or aloud reading, a Production Effect (PE) paradigm. As the PE represents enhanced memory for words read aloud relative to words read silently during study, we focused on the effect of noise on this robust memory phenomenon. The results showed that (a) steady-state energetic noise did not affect memory, with a recall advantage for aloud words (PE), comparable to a no-noise condition, (b) fluctuating-energetic noise and fluctuating-informational (eight-talkers babble) noise eliminated the PE, with similar recall for aloud and silent items. These results are discussed in light of their theoretical implications, stressing the role of attention in the PE. Ecological implications regarding studying in noisy environments are suggested. Copyright © 2018 Elsevier B.V. All rights reserved.

  17. Background Acoustic Noise Models for the IMS Hydroacoustic Stations

    Science.gov (United States)

    2010-09-01

    BACKGROUND ACOUSTIC NOISE MODELS FOR THE IMS HYDROACOUSTIC STATIONS Philip E. Harben and Terri F. Hauk Lawrence Livermore National Laboratory ...levels in the ocean have been increasing for the past several decades (McDonald, 2006) yet many of our hydroacoustic detection assessment tools use...dB since the 1960’s. To address this issue and provide accurate noise models at each of the six International Monitoring System (IMS) hydroacoustic

  18. Talker and background noise specificity in spoken word recognition memory

    Directory of Open Access Journals (Sweden)

    Angela Cooper

    2017-11-01

    Full Text Available Prior research has demonstrated that listeners are sensitive to changes in the indexical (talker-specific characteristics of speech input, suggesting that these signal-intrinsic features are integrally encoded in memory for spoken words. Given that listeners frequently must contend with concurrent environmental noise, to what extent do they also encode signal-extrinsic details? Native English listeners’ explicit memory for spoken English monosyllabic and disyllabic words was assessed as a function of consistency versus variation in the talker’s voice (talker condition and background noise (noise condition using a delayed recognition memory paradigm. The speech and noise signals were spectrally-separated, such that changes in a simultaneously presented non-speech signal (background noise from exposure to test would not be accompanied by concomitant changes in the target speech signal. The results revealed that listeners can encode both signal-intrinsic talker and signal-extrinsic noise information into integrated cognitive representations, critically even when the two auditory streams are spectrally non-overlapping. However, the extent to which extra-linguistic episodic information is encoded alongside linguistic information appears to be modulated by syllabic characteristics, with specificity effects found only for monosyllabic items. These findings suggest that encoding and retrieval of episodic information during spoken word processing may be modulated by lexical characteristics.

  19. Measurement of Acceptable Noise Level with Background Music

    Science.gov (United States)

    Ahn, Hyun-Jung; Bahng, Junghwa

    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 investigated the relationships between individual ANLs and the familiarity of music samples and between music ANLs and subjective preference. Subjects and Methods Forty-one participants were seperated into two groups according to their ANLs, 29 low-ANL listeners and 12 high-ANL listeners. Using Korean ANL material, the individual ANLs were measured based on the listeners' most comfortable listening level and BNL. The ANLs were measured in six conditions, with different music tempo (fast, slow) and genre (K-pop, pop, classical) in a counterbalanced order. Results Overall, ANLs did not differ by the tempo of background music, but music genre significantly affected individual ANLs. We observed relatively higher ANLs with K-pop music and relatively lower ANLs with classical music. This tendency was similar in both low-ANL and high-ANL groups. However, the subjective ratings of music familiarity and preference affected ANLs differently for low-ANL and high-ANL groups. In contrast to the low-ANL listeners, the ANLs of the high-ANL listeners were significantly affected by music familiarity and preference. Conclusions The genre of background music affected ANLs obtained using background music. The degree of music familiarity and preference appears to be associated with individual susceptibility to background music only for listeners who are greatly annoyed by background noise (high-ANL listeners). PMID:26413573

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

    International Nuclear Information System (INIS)

    Reiser, Ingrid; Nishikawa, Robert M.

    2006-01-01

    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. Measurement of Acceptable Noise Level with Background Music.

    Science.gov (United States)

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

    2015-09-01

    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 investigated the relationships between individual ANLs and the familiarity of music samples and between music ANLs and subjective preference. Forty-one participants were seperated into two groups according to their ANLs, 29 low-ANL listeners and 12 high-ANL listeners. Using Korean ANL material, the individual ANLs were measured based on the listeners' most comfortable listening level and BNL. The ANLs were measured in six conditions, with different music tempo (fast, slow) and genre (K-pop, pop, classical) in a counterbalanced order. Overall, ANLs did not differ by the tempo of background music, but music genre significantly affected individual ANLs. We observed relatively higher ANLs with K-pop music and relatively lower ANLs with classical music. This tendency was similar in both low-ANL and high-ANL groups. However, the subjective ratings of music familiarity and preference affected ANLs differently for low-ANL and high-ANL groups. In contrast to the low-ANL listeners, the ANLs of the high-ANL listeners were significantly affected by music familiarity and preference. The genre of background music affected ANLs obtained using background music. The degree of music familiarity and preference appears to be associated with individual susceptibility to background music only for listeners who are greatly annoyed by background noise (high-ANL listeners).

  2. 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......, the 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....

  3. 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...... artifacts, were investigated. The quality of the reproduced sound was evaluated both objectively and subjectively with respect to the reference sounds, at points where telecommunications devices would be potentially placed around the head. The highest regularization value gave the best results...

  4. Variations of Background Seismic Noise Before Strong Earthquakes, Kamchatka.

    Science.gov (United States)

    Kasimova, V.; Kopylova, G.; Lyubushin, A.

    2017-12-01

    The network of broadband seismic stations of Geophysical Service (Russian Academy of Science) works on the territory of Kamchatka peninsula in the Far East of Russia. We used continuous records on Z-channels at 21 stations for creation of background seismic noise time series in 2011-2017. Average daily parameters of multi-fractal spectra of singularity have been calculated at each station using 1-minute records. Maps and graphs of their spatial distribution and temporal changes were constructed at time scales from days to several years. The analysis of the coherent behavior of the time series of the statistics was considered. The technique included the splitting of seismic network into groups of stations, taking into account the coastal effect, the network configuration and the main tectonic elements of Kamchatka. Then the time series of median values of noise parameters from each group of stations were made and the frequency-time diagrams of the evolution of the spectral measure of the coherent behavior of four time series were analyzed. The time intervals and frequency bands of the maximum values showing the increase of coherence in the changes of all statistics were evaluated. The strong earthquakes with magnitudes M=6.9-8.3 occurred near the Kamchatka peninsula during the observations. The synchronous variations of the background noise parameters and increase in the coherent behavior of the median values of statistical parameters was shown before two earthquakes 2013 (February 28, Mw=6.9; May 24, Mw=8.3) within 3-9 months and before earthquake of January 30, 2016, Mw=7.2 within 3-6 months. The maximum effect of increased coherence in the range of periods 4-5.5 days corresponds to the time of preparation of two strong earthquakes in 2013 and their aftershock processes. Peculiarities in changes of statistical parameters at stages of preparation of strong earthquakes indicate the attenuation in high-amplitude outliers and the loss of multi-fractal properties in

  5. Audiomotor Perceptual Training Enhances Speech Intelligibility in Background Noise.

    Science.gov (United States)

    Whitton, Jonathon P; Hancock, Kenneth E; Shannon, Jeffrey M; Polley, Daniel B

    2017-11-06

    Sensory and motor skills can be improved with training, but learning is often restricted to practice stimuli. As an exception, training on closed-loop (CL) sensorimotor interfaces, such as action video games and musical instruments, can impart a broad spectrum of perceptual benefits. Here we ask whether computerized CL auditory training can enhance speech understanding in levels of background noise that approximate a crowded restaurant. Elderly hearing-impaired subjects trained for 8 weeks on a CL game that, like a musical instrument, challenged them to monitor subtle deviations between predicted and actual auditory feedback as they moved their fingertip through a virtual soundscape. We performed our study as a randomized, double-blind, placebo-controlled trial by training other subjects in an auditory working-memory (WM) task. Subjects in both groups improved at their respective auditory tasks and reported comparable expectations for improved speech processing, thereby controlling for placebo effects. Whereas speech intelligibility was unchanged after WM training, subjects in the CL training group could correctly identify 25% more words in spoken sentences or digit sequences presented in high levels of background noise. Numerically, CL audiomotor training provided more than three times the benefit of our subjects' hearing aids for speech processing in noisy listening conditions. Gains in speech intelligibility could be predicted from gameplay accuracy and baseline inhibitory control. However, benefits did not persist in the absence of continuing practice. These studies employ stringent clinical standards to demonstrate that perceptual learning on a computerized audio game can transfer to "real-world" communication challenges. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. 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.

  7. 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.

  8. Urban background noise mapping: The multiple-reflection correction term

    NARCIS (Netherlands)

    Hornikx, M.; Forssén, J.; Botteldooren, D.; Renterghem, T. van; Wei, W.; Ögren, M.; Salomons, E.

    2014-01-01

    Mapping of road traffic noise in urban areas according to standardized engineering calculation methods systematically results in an underestimation of noise levels at areas shielded from direct exposure to noise, such as inner yards. In most engineering methods, road traffic lanes are represented by

  9. 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.

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

    OpenAIRE

    S?derlund, G?ran BW; Sikstr?m, Sverker; Loftesnes, Jan M; Sonuga-Barke, Edmund J

    2010-01-01

    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. Me...

  11. 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.

  12. Background noise exerts diverse effects on the cortical encoding of foreground sounds.

    Science.gov (United States)

    Malone, B J; Heiser, Marc A; Beitel, Ralph E; Schreiner, Christoph E

    2017-08-01

    In natural listening conditions, many sounds must be detected and identified in the context of competing sound sources, which function as background noise. Traditionally, noise is thought to degrade the cortical representation of sounds by suppressing responses and increasing response variability. However, recent studies of neural network models and brain slices have shown that background synaptic noise can improve the detection of signals. Because acoustic noise affects the synaptic background activity of cortical networks, it may improve the cortical responses to signals. We used spike train decoding techniques to determine the functional effects of a continuous white noise background on the responses of clusters of neurons in auditory cortex to foreground signals, specifically frequency-modulated sweeps (FMs) of different velocities, directions, and amplitudes. Whereas the addition of noise progressively suppressed the FM responses of some cortical sites in the core fields with decreasing signal-to-noise ratios (SNRs), the stimulus representation remained robust or was even significantly enhanced at specific SNRs in many others. Even though the background noise level was typically not explicitly encoded in cortical responses, significant information about noise context could be decoded from cortical responses on the basis of how the neural representation of the foreground sweeps was affected. These findings demonstrate significant diversity in signal in noise processing even within the core auditory fields that could support noise-robust hearing across a wide range of listening conditions. NEW & NOTEWORTHY The ability to detect and discriminate sounds in background noise is critical for our ability to communicate. The neural basis of robust perceptual performance in noise is not well understood. We identified neuronal populations in core auditory cortex of squirrel monkeys that differ in how they process foreground signals in background noise and that may

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

    Science.gov (United States)

    Söderlund, Göran B W; Sikström, Sverker; Loftesnes, Jan M; Sonuga-Barke, Edmund J

    2010-09-29

    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. 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. 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. 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.

  14. 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.

  15. The Effect of Background Noise on the Word Activation Process in Nonnative Spoken-Word Recognition

    Science.gov (United States)

    Scharenborg, Odette; Coumans, Juul M. J.; van Hout, Roeland

    2018-01-01

    This article investigates 2 questions: (1) does the presence of background noise lead to a differential increase in the number of simultaneously activated candidate words in native and nonnative listening? And (2) do individual differences in listeners' cognitive and linguistic abilities explain the differential effect of background noise on…

  16. 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…

  17. Talker and background noise specificity in spoken word recognition memory

    OpenAIRE

    Cooper, Angela; Bradlow, Ann R.

    2017-01-01

    Prior research has demonstrated that listeners are sensitive to changes in the indexical (talker-specific) characteristics of speech input, suggesting that these signal-intrinsic features are integrally encoded in memory for spoken words. Given that listeners frequently must contend with concurrent environmental noise, to what extent do they also encode signal-extrinsic details? Native English listeners’ explicit memory for spoken English monosyllabic and disyllabic words was assessed as a fu...

  18. Detecting impact signal in mechanical fault diagnosis under chaotic and Gaussian background noise

    Science.gov (United States)

    Hu, Jinfeng; Duan, Jie; Chen, Zhuo; Li, Huiyong; Xie, Julan; Chen, Hanwen

    2018-01-01

    In actual fault diagnosis, useful information is often submerged in heavy noise, and the feature information is difficult to extract. Traditional methods, such like stochastic resonance (SR), which using noise to enhance weak signals instead of suppressing noise, failed in chaotic background. Neural network, which use reference sequence to estimate and reconstruct the background noise, failed in white Gaussian noise. To solve these problems, a novel weak signal detection method aimed at the problem of detecting impact signal buried under heavy chaotic and Gaussian background noise is proposed. First, the proposed method obtains the virtual reference sequence by constructing the Hankel data matrix. Then an M-order optimal FIR filter is designed, which can minimize the output power of background noise and pass the weak periodic signal undistorted. Finally, detection and reconstruction of the weak periodic signal are achieved from the output SBNR (signal to background noise ratio). The simulation shows, compared with the stochastic resonance (SR) method, the proposed method can detect the weak periodic signal in chaotic noise background while stochastic resonance (SR) method cannot. Compared with the neural network method, (a) the proposed method does not need a reference sequence while neural network method needs one; (b) the proposed method can detect the weak periodic signal in white Gaussian noise background while the neural network method fails, in chaotic noise background, the proposed method can detect the weak periodic signal under a lower SBNR (about 8-17 dB lower) than the neural network method; (c) the proposed method can reconstruct the weak periodic signal precisely.

  19. The method of narrow-band audio classification based on universal noise background model

    Science.gov (United States)

    Rui, Rui; Bao, Chang-chun

    2013-03-01

    Audio classification is the basis of content-based audio analysis and retrieval. The conventional classification methods mainly depend on feature extraction of audio clip, which certainly increase the time requirement for classification. An approach for classifying the narrow-band audio stream based on feature extraction of audio frame-level is presented in this paper. The audio signals are divided into speech, instrumental music, song with accompaniment and noise using the Gaussian mixture model (GMM). In order to satisfy the demand of actual environment changing, a universal noise background model (UNBM) for white noise, street noise, factory noise and car interior noise is built. In addition, three feature schemes are considered to optimize feature selection. The experimental results show that the proposed algorithm achieves a high accuracy for audio classification, especially under each noise background we used and keep the classification time less than one second.

  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

    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...... on the number of talkers in the background noise. The presented signal to noise ratios were not a significant factor on the measured intelligibility performance. Conclusion: In agreement with earlier research, high working memory allowed better speech intelligibility when fast compression was applied...

  1. Study of the background noise in microwave GaAsFET devices

    International Nuclear Information System (INIS)

    Serrano S, A.

    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. (author)

  2. Assessment of speech intelligibility in background noise and reverberation

    DEFF Research Database (Denmark)

    Nielsen, Jens Bo

    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 modified version of CLUE where the speech material and the scoring rules have been reconsidered. An extensive validation of the modified test was conducted with both normal-hearing and hearing-impaired listeners. The validation showed that the test produces reliable results for both groups of listeners....... An 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...

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

    Science.gov (United States)

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

    2016-01-01

    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. 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 slow-acting compression amplification combined with individual frequency-gain shaping was applied to compensate for the individual's hearing loss. Better speech intelligibility scores were observed for participants with high working memory when fast compression was applied than when slow compression was applied. The low working memory group behaved in the opposite way and performed better under slow compression compared with fast compression. There was also a significant effect of the extent of amplitude modulation in the background noise, such that the magnitude of the score difference (fast versus slow compression) depended on the number of talkers in the background noise. The presented signal to noise ratios were not a significant factor on the measured intelligibility performance. In agreement with earlier research, high working memory allowed better speech intelligibility when fast compression was applied in modulated background noise. In the present experiment, that effect was present regardless of the extent of background noise modulation.

  4. Effects of background noises on nonlinear dynamics of a modelled thermoacoustic combustor.

    Science.gov (United States)

    Li, Xinyan; Zhao, Dan; Li, Xuan

    2018-01-01

    In this work, the effects of background noises on nonlinear dynamics of a modelled standing-wave thermoacoustic system with subcritical Hopf bifurcation behaviors are studied. These noises include (1) pressure-coupled (acoustic), (2) velocity-coupled (flow), and (3) external combustion noise. It is found that these three types of background noises play important, but different roles in changing the hysteresis width and stability boundary. In addition, the stochastic transition from stability to instability is investigated, as the noise intensity is varied. Two different stochastic P-bifurcations are identified. One is related to a craterlike probability density distribution. The other is associated with a probability density distribution characterized with two peaks and one trough. With each type of noise affecting the system's stochastic behaviors being evaluated, the effect of two different types of noises is then studied. It is shown that the combined noises (types 1 and 2) cannot only destabilize global stable thermoacoustic system, but also stabilize linearly unstable system. This depends strongly on the superimposition form of the two types of noises. In addition, when the thermoacoustic system is disturbed by the combined noise (types 3 and 1 or types 3 and 2), the transition process is dominated by the combustion noise.

  5. The Effect of Background Music and Background Noise on the Task Performance of Introverts and Extraverts

    Science.gov (United States)

    Cassidy, Gianna; MacDonald, Raymond A. R.

    2007-01-01

    The study investigated the effects of music with high arousal potential and negative affect (HA), music with low arousal potential and positive affect (LA), and everyday noise, on the cognitive task performance of introverts and extraverts. Forty participants completed five cognitive tasks: immediate recall, free recall, numerical and delayed…

  6. Spectral features of background ULF noise during magnetic storms

    Science.gov (United States)

    Kotik, Dmitry; Ermakova, Elena; Ryabov, Alexander; Shchecoldin, Aexander

    The monitoring of tangential components of ULF noise below first Schumann resonance was permanently provided since 2003 up to now at mid-latitude station New Life (56N, 44,7E). The regular structure in ULF spectrograms named SRS -spectral resonance structure could be observed practically every night excepting years of solar activity maximum. The SRS appears in the ULF noise due existing the resonator for Alfven waves in the ionosphere at heights from the bottom up to 600 -1000 km [1]. It was noticed that during magnetically disturbed time the strong anti-correlation between the intensity of SRS events and K index from station on neighbor magnetic meridian [2]. For more detail investigation it was choused several magnetic storms. First one is storm witch has began at November 20, 2003 with maximum Kp=9 (strong), second -at March 19, 2006 with Kp=6+ (moderate) and the third -at November 25, 2008 with Kp=5 (weak). The spectra of magnetic component amplitude and polarization parameter were analyzed. The comparison with ionosond and magnetic field data as well as world TEC maps for mentioned storm periods were made. The dynamics of changing the properties of ULF spectra during the storms were explored. The general regularities of these changes were displayed. One of the prominent feathers appeared at the end of the strong and moderate storms looked like fish shoals. Perhaps this kind of ULF bursts is the same nature as well known pearls pulsation but displayed in broad frequency range 1-6 Hz. May be it could be classified as special spectral structure. The analysis of changing the properties of ULF spectra during the storms together with geo-physical data has shown that the main regularities in changes the SRS caused by changing of the ionospheric parameters above the observation point. But some of ULF spectral features are results of interaction waves and particles in the magnetosphere. 1. Belyaev P.P., Polyakov S.V., Ermakova E.N., Isaev S.V. Solar cycle variations in

  7. Adaptive dictionary based approach for background noise and speaker classification and subsequent source separation

    OpenAIRE

    Girish, K V Vijay; Ramakrishnan, A G; Ananthapadmanabha, T V

    2016-01-01

    A judicious combination of dictionary learning methods, block sparsity and source recovery algorithm are used in a hierarchical manner to identify the noises and the speakers from a noisy conversation between two people. Conversations are simulated using speech from two speakers, each with a different background noise, with varied SNR values, down to -10 dB. Ten each of randomly chosen male and female speakers from the TIMIT database and all the noise sources from the NOISEX database are used...

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

    OpenAIRE

    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 ...

  9. Neural underpinnings of background acoustic noise in normal aging and mild cognitive impairment.

    Science.gov (United States)

    Sinanaj, Indrit; Montandon, Marie-Louise; Rodriguez, Cristelle; Herrmann, François; Santini, Francesco; Haller, Sven; Giannakopoulos, Panteleimon

    2015-12-03

    Previous contributions in younger cohorts have revealed that reallocation of cerebral resources, a crucial mechanism for working memory (WM), may be disrupted by parallel demands of background acoustic noise suppression. To date, no study has explored the impact of such disruption on brain activation in elderly individuals with or without subtle cognitive deficits. We performed a functional Magnetic Resonance Imaging (fMRI) study in 23 cases (mean age=75.7 y.o., 16 men) with mild cognitive impairment (MCI) and 16 elderly healthy controls (HC, mean age=70.1 y.o., three men) using a 2-back WM task, under two distinct MRI background acoustic noise conditions (louder vs. lower noise echo-planar imaging). General linear models were used to assess brain activation as a function of group and noise. In both groups, lower background noise is associated with increased activation of the working memory network (WMN). A decrease of the normally observed deactivation of the default mode network (DMN) is found under louder noise in both groups. Unlike HC, MCI cases also show decreased deactivation of the DMN under both louder and lower background noise. Under louder noise, this decrease is observed in anterior parts of the DMN in HC, and in the posterior cingulate cortex in MCI cases. Our results suggest that background acoustic noise has a differential impact on WMN activation in normal aging as a function of the cognitive status. Only louder noise has a disruptive effect on the usually observed DMN deactivation during WM task performance in HC. In contrast, MCI cases show altered DMN reactivity even in the presence of lower noise. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

  10. 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…

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

    International Nuclear Information System (INIS)

    Solomon, Justin; Samei, Ehsan

    2014-01-01

    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

  12. Effect of background noise on neuronal coding of interaural level difference cues in rat inferior colliculus

    Science.gov (United States)

    Mokri, Yasamin; Worland, Kate; Ford, Mark; Rajan, Ramesh

    2015-01-01

    Humans can accurately localize sounds even in unfavourable signal-to-noise conditions. To investigate the neural mechanisms underlying this, we studied the effect of background wide-band noise on neural sensitivity to variations in interaural level difference (ILD), the predominant cue for sound localization in azimuth for high-frequency sounds, at the characteristic frequency of cells in rat inferior colliculus (IC). Binaural noise at high levels generally resulted in suppression of responses (55.8%), but at lower levels resulted in enhancement (34.8%) as well as suppression (30.3%). When recording conditions permitted, we then examined if any binaural noise effects were related to selective noise effects at each of the two ears, which we interpreted in light of well-known differences in input type (excitation and inhibition) from each ear shaping particular forms of ILD sensitivity in the IC. At high signal-to-noise ratios (SNR), in most ILD functions (41%), the effect of background noise appeared to be due to effects on inputs from both ears, while for a large percentage (35.8%) appeared to be accounted for by effects on excitatory input. However, as SNR decreased, change in excitation became the dominant contributor to the change due to binaural background noise (63.6%). These novel findings shed light on the IC neural mechanisms for sound localization in the presence of continuous background noise. They also suggest that some effects of background noise on encoding of sound location reported to be emergent in upstream auditory areas can also be observed at the level of the midbrain. PMID:25865218

  13. 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

    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...

  14. Very broadband seismic background noise analysis of permanent good vaulted seismic stations

    Science.gov (United States)

    Abd el-aal, Abd el-aziz Khairy

    2013-04-01

    This paper describes the results of a preliminary study conducted to analyze seismic background noise at sites of recently deployed very broadband stations of the Egyptian National Seismological Network (ENSN). The main purpose of the study is to assess the effects of permanent seismic vault construction and also to establish characteristics and origin of seismic noise at those sites. Another goal of this study is to determine the time needed for noise at those sites to stabilize. The power spectral densities of background noise at short period band (SP), very broadband (VBB), and ultra long period band (ULP) for each component of each broadband seismometer deployed in the different investigated sites are calculated. A MATLAB code has been developed that manages data processing and data analysis and compares the results with the high-noise model (NHNM) and low-noise model (NLNM) of Peterson (1993). Based on the obtained analysis, the noise stability and the efficiency of each station to record regional and teleseismic events are measured. The results of this study could be used in the future to evaluate station quality, to improve those processes that require background noise values, such as automatic association, and to improve the estimation of station and network detection and location thresholds.

  15. Extraction of scattering echo time by surf noise background subtracted autocorrelation.

    Science.gov (United States)

    Li, Xiaolei; Chi, Jing; Gao, Dazhi; Li, Jie; Wang, Ning

    2017-07-01

    Extracting echo time is an important step in scatterer detection by ambient noise, while in general the scattered signal is weak and submerged in the background. An experiment of a Polyvinyl chloride pipe in a coastline surf noise environment is designed to extract the pipe's echo time by noise autocorrelation. As expected, the scattered wave of the pipe is submerged in an autocorrelation signal. A method called background subtracted autocorrelation is proposed in this paper, which can retrieve scattered echo time from autocorrelation signal effectively. And the biggest relative error of extracted echo time is less than 2% in the experiment.

  16. The Effects of Background Noise on the Performance of an Automatic Speech Recogniser

    Science.gov (United States)

    Littlefield, Jason; HashemiSakhtsari, Ahmad

    2002-11-01

    Ambient or environmental noise is a major factor that affects the performance of an automatic speech recognizer. Large vocabulary, speaker-dependent, continuous speech recognizers are commercially available. Speech recognizers, perform well in a quiet environment, but poorly in a noisy environment. Speaker-dependent speech recognizers require training prior to them being tested, where the level of background noise in both phases affects the performance of the recognizer. This study aims to determine whether the best performance of a speech recognizer occurs when the levels of background noise during the training and test phases are the same, and how the performance is affected when the levels of background noise during the training and test phases are different. The relationship between the performance of the speech recognizer and upgrading the computer speed and amount of memory as well as software version was also investigated.

  17. Objective measures of listening effort: effects of background noise and noise reduction.

    Science.gov (United States)

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

    2009-10-01

    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. To address this, the hypothesis tested here is that the positive effects of NR might be to reduce cognitive effort directed toward speech reception, making it available for other tasks. Normal-hearing individuals participated in 2 dual-task experiments, in which 1 task was to report sentences or words in noise set to various signal-to-noise ratios. Secondary tasks involved either holding words in short-term memory or responding in a complex visual reaction-time task. At low values of signal-to-noise ratio, although NR had no positive effect on speech reception thresholds, it led to better performance on the word-memory task and quicker responses in visual reaction times. Results from both dual tasks support the hypothesis that NR reduces listening effort and frees up cognitive resources for other tasks. Future hearing aid research should incorporate objective measurements of cognitive benefits.

  18. Nodule detection in digital chest radiography: Part of image background acting as pure noise

    International Nuclear Information System (INIS)

    Baath, M.; Haakansson, M.; Boerjesson, S.; Kheddache, S.; Grahn, A.; Bochud, F. O.; Verdun, F. R.; Maansson, L. G.

    2005-01-01

    There are several factors that influence the radiologist's ability to detect a specific structure/lesion in a radiograph. Three factors that are commonly known to be of major importance are the signal itself, the system noise and the projected anatomy. The aim of this study was to determine to what extent the image background acts as pure noise for the detection of subtle lung nodules in five different regions of the chest. A receiver operating characteristic (ROC) study with five observers was conducted on two different sets of images, clinical chest X-ray images and images with a similar power spectrum as the clinical images but with a random phase spectrum, resulting in an image background containing pure noise. Simulated designer nodules with a full-width-at-fifth-maximum of 10 mm but with varying contrasts were added to the images. As a measure of the part of the image background that acts as pure noise, the ratio between the contrast needed to obtain an area under the ROC curve of 0.80 in the clinical images to that in the random-phase images was used. The ratio ranged from 0.40 (in the lateral pulmonary regions) to 0.83 (in the hilar regions) indicating that there was a large difference between different regions regarding to what extent the image background acted as pure noise; and that in the hilar regions the image background almost completely acted as pure noise for the detection of 10 mm nodules. (authors)

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

    International Nuclear Information System (INIS)

    Liu, Dunge; Xu, Xin; Huang, Chao; Zhu, Wanhua; Liu, Xiaojun; Fang, Guangyou; Yu, Gang

    2015-01-01

    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)

  20. A convenient method for observation of electrical signals obscured by background noise

    International Nuclear Information System (INIS)

    Kurakado, M.; Katano, R.; Mazaki, H.

    1982-01-01

    To make precise observation of the shape of small and rapid electrical signals obscured by background noise, a measuring system which consists of an amplifier (150 MHz), a sampling oscilloscope (1 GHz), a multichannel analyzer, and some commercically available components has been developed. By the use of this system operated condition, small (> 2 μV) and rapid (rise time > 3 ns) signals can be effectively brought out of the noise level. (orig.)

  1. Dolphins adjust species-specific frequency parameters to compensate for increasing background noise.

    Science.gov (United States)

    Papale, Elena; Gamba, Marco; Perez-Gil, Monica; Martin, Vidal Martel; Giacoma, Cristina

    2015-01-01

    An increase in ocean noise levels could interfere with acoustic communication of marine mammals. In this study we explored the effects of anthropogenic and natural noise on the acoustic properties of a dolphin communication signal, the whistle. A towed array with four elements was used to record environmental background noise and whistles of short-beaked common-, Atlantic spotted- and striped-dolphins in the Canaries archipelago. Four frequency parameters were measured from each whistle, while Sound Pressure Levels (SPL) of the background noise were measured at the central frequencies of seven one-third octave bands, from 5 to 20 kHz. Results show that dolphins increase the whistles' frequency parameters with lower variability in the presence of anthropogenic noise, and increase the end frequency of their whistles when confronted with increasing natural noise. This study provides the first evidence that the synergy among SPLs has a role in shaping the whistles' structure of these three species, with respect to both natural and anthropogenic noise.

  2. Dolphins adjust species-specific frequency parameters to compensate for increasing background noise.

    Directory of Open Access Journals (Sweden)

    Elena Papale

    Full Text Available An increase in ocean noise levels could interfere with acoustic communication of marine mammals. In this study we explored the effects of anthropogenic and natural noise on the acoustic properties of a dolphin communication signal, the whistle. A towed array with four elements was used to record environmental background noise and whistles of short-beaked common-, Atlantic spotted- and striped-dolphins in the Canaries archipelago. Four frequency parameters were measured from each whistle, while Sound Pressure Levels (SPL of the background noise were measured at the central frequencies of seven one-third octave bands, from 5 to 20 kHz. Results show that dolphins increase the whistles' frequency parameters with lower variability in the presence of anthropogenic noise, and increase the end frequency of their whistles when confronted with increasing natural noise. This study provides the first evidence that the synergy among SPLs has a role in shaping the whistles' structure of these three species, with respect to both natural and anthropogenic noise.

  3. Background Registration-Based Adaptive Noise Filtering of LWIR/MWIR Imaging Sensors for UAV Applications.

    Science.gov (United States)

    Kim, Byeong Hak; Kim, Min Young; Chae, You Seong

    2017-12-27

    Unmanned aerial vehicles (UAVs) are equipped with optical systems including an infrared (IR) camera such as electro-optical IR (EO/IR), target acquisition and designation sights (TADS), or forward looking IR (FLIR). However, images obtained from IR cameras are subject to noise such as dead pixels, lines, and fixed pattern noise. Nonuniformity correction (NUC) is a widely employed method to reduce noise in IR images, but it has limitations in removing noise that occurs during operation. Methods have been proposed to overcome the limitations of the NUC method, such as two-point correction (TPC) and scene-based NUC (SBNUC). However, these methods still suffer from unfixed pattern noise. In this paper, a background registration-based adaptive noise filtering (BRANF) method is proposed to overcome the limitations of conventional methods. The proposed BRANF method utilizes background registration processing and robust principle component analysis (RPCA). In addition, image quality verification methods are proposed that can measure the noise filtering performance quantitatively without ground truth images. Experiments were performed for performance verification with middle wave infrared (MWIR) and long wave infrared (LWIR) images obtained from practical military optical systems. As a result, it is found that the image quality improvement rate of BRANF is 30% higher than that of conventional NUC.

  4. 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.

  5. 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.; Carr, Kali Woodruff; Nicol, Trent; Bradlow, Ann R.; Kraus, Nina

    2015-01-01

    Early childhood is a critical period of auditory learning, during which children are constantly mapping sounds to meaning. But learning rarely occurs under 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 properties

  6. 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

  7. Fabry–Perot interferometer as a solar background noise suppressor: application to daytime lidar

    Directory of Open Access Journals (Sweden)

    Karnam Raghunath

    2012-06-01

    Full Text Available Continuous atmospheric probing by a lidar is a requirement for many applications. However, due to high solar background noise during the daytime, lidar operations are mostly restricted to night-time. While many techniques are in practice, like reducing the receiver field of view, changing the view angle, introducing a narrow band Interference Filter (IF, these are applied to circumvent problems, rather than to suppress the noise. Using a Fabry-Perot interferometer as a narrow passband filter for solar background noise suppression is a known technique, and its potential is exploited in our system. An optical-fiber-coupled lidar system with its transmitter injection seeded was developed and has been operated during the daytime at Gadanki (13.6˚N, 79.2˚ E. The signal-to-noise ratio of the return signal is used as the performance indicator, to evaluate the improvements. Signal-to-noise ratios with and without the Fabry-Perot interferometer are measured with near identical test set-ups. The signal-to-noise ratio enhancement factor is ca. 4, in agreement with the theoretical value. The performance is compared when the receiver fields of view are changed.

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

    Science.gov (United States)

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

    2011-06-01

    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 our case, low noise accelerometers), a data acquisition system, and processing software. Background noise excitation from the floor has the additional advantage that any non-linearity in the suspension system relevant to the actual vibration amplitudes will be taken into account. Measurement time is typically a few minutes, depending on the amount of background noise. The (coherent) transfer of the vibrations in the floor to the platform, as well as the (non-coherent) acoustical noise pick-up by the platform are measured. Since we use calibrated sensors, the absolute value of the vibration levels is established and can be expressed in vibration criterion curves. Transfer measurements are shown and discussed for two pneumatic isolated optical tables, a spring suspension system, and a simple foam suspension system.

  9. 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)

  10. Background MR gradient noise and non-auditory BOLD activations: a data-driven perspective.

    Science.gov (United States)

    Haller, Sven; Homola, György A; Scheffler, Klaus; Beckmann, Christian F; Bartsch, Andreas J

    2009-07-28

    The effect of echoplanar imaging (EPI) acoustic background noise on blood oxygenation level dependent (BOLD) activations was investigated. Two EPI pulse sequences were compared: (i) conventional EPI with a pulsating sound component of typically 8-10 Hz, which is a potent physiological stimulus, and (ii) the more recently developed continuous-sound EPI, which is perceived as less distractive despite equivalent peak sound pressure levels. Sixteen healthy subjects performed an established demanding visual n-back working memory task. Using an exploratory data analysis technique (tensorial probabilistic independent component analysis; tensor-PICA), we studied the inter-session/within-subject response variability introduced by continuous-sound versus conventional EPI acoustic background noise in addition to temporal and spatial signal characteristics. The analysis revealed a task-related component associated with the established higher-level working memory and motor feedback response network, which exhibited a significant 19% increase in its average effect size for the continuous-sound as opposed to conventional EPI. Stimulus-related lower-level activations, such as primary visual areas, were not modified. EPI acoustic background noise influences much more than the auditory system per se. This analysis provides additional evidence for an enhancement of task-related, extra-auditory BOLD activations by continuous-sound EPI due to less distractive acoustic background gradient noise.

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

    NARCIS (Netherlands)

    Segerink, Franciscus B.; Korterik, Jeroen P.; Offerhaus, Herman 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

  12. How hearing aids, background noise, and visual cues influence objective listening effort.

    Science.gov (United States)

    Picou, Erin M; Ricketts, Todd A; Hornsby, Benjamin W Y

    2013-09-01

    The purpose of this article was to evaluate factors that influence the listening effort experienced when processing speech for people with hearing loss. Specifically, the change in listening effort resulting from introducing hearing aids, visual cues, and background noise was evaluated. An additional exploratory aim was to investigate the possible relationships between the magnitude of listening effort change and individual listeners' working memory capacity, verbal processing speed, or lipreading skill. Twenty-seven participants with bilateral sensorineural hearing loss were fitted with linear behind-the-ear hearing aids and tested using a dual-task paradigm designed to evaluate listening effort. The primary task was monosyllable word recognition and the secondary task was a visual reaction time task. The test conditions varied by hearing aids (unaided, aided), visual cues (auditory-only, auditory-visual), and background noise (present, absent). For all participants, the signal to noise ratio was set individually so that speech recognition performance in noise was approximately 60% in both the auditory-only and auditory-visual conditions. In addition to measures of listening effort, working memory capacity, verbal processing speed, and lipreading ability were measured using the Automated Operational Span Task, a Lexical Decision Task, and the Revised Shortened Utley Lipreading Test, respectively. In general, the effects measured using the objective measure of listening effort were small (~10 msec). Results indicated that background noise increased listening effort, and hearing aids reduced listening effort, while visual cues did not influence listening effort. With regard to the individual variables, verbal processing speed was negatively correlated with hearing aid benefit for listening effort; faster processors were less likely to derive benefit. Working memory capacity, verbal processing speed, and lipreading ability were related to benefit from visual cues. No

  13. Background Noise of the Aldeia da Serra Region (Portugal) from a temporary broad band network

    Science.gov (United States)

    Wachilala, Piedade; Borges, José; Caldeira, Bento; Bezzeghoud, Mourad

    2017-04-01

    In this study, we analyse seismic background noise to assess the effect of noise based on the detectability of a temporary network constituted by DOCTAR (Deep Ocean Test Array), who have been deployed in a period between 2011 and 2012 in Portugal mainland, and the Évora permanent seismic station. This network is constituted by 14 digital broadband stations (14 CMG-3ESP and one STS2 sensors) with a flat response between the 60 sec to 50 Hz, 24-bit and 120s to 60Hz respectively. The temporary network was operated in continuous recording mode (three-components) in a region located in the north of the region of Évora, within a radius of about 30 km around the village of Aldeia da Serra, region in which there is an important seismic activity in the context of Portugal mainland. We calculated power spectral densities of background noise for each station/component and compare them with high-noise model and low-noise model of Peterson (1993). We consider different for day and night local and for different periods of the year. Power spectral density estimates show moderate noise levels with all stations falling within the high and low bounds of Peterson (1993). Considering the results of the noise, we estimate the detection limit of each station and consequently the detectability of the network. From this information and taking in attention the events recorded during the period of DOCTAR operation we analyse the improvement promoted by this temporary network regarding the existent seismic networks to the local seismicity study. This work was partially supported by COMPETE 2020 program (POCI-01-0145-FEDER-007690 project). We acknowledge GFZ Potsdam for providing part of the data used in this study.

  14. An improved algorithm of laser spot center detection in strong noise background

    Science.gov (United States)

    Zhang, Le; Wang, Qianqian; Cui, Xutai; Zhao, Yu; Peng, Zhong

    2018-01-01

    Laser spot center detection is demanded in many applications. The common algorithms for laser spot center detection such as centroid and Hough transform method have poor anti-interference ability and low detection accuracy in the condition of strong background noise. In this paper, firstly, the median filtering was used to remove the noise while preserving the edge details of the image. Secondly, the binarization of the laser facula image was carried out to extract target image from background. Then the morphological filtering was performed to eliminate the noise points inside and outside the spot. At last, the edge of pretreated facula image was extracted and the laser spot center was obtained by using the circle fitting method. In the foundation of the circle fitting algorithm, the improved algorithm added median filtering, morphological filtering and other processing methods. This method could effectively filter background noise through theoretical analysis and experimental verification, which enhanced the anti-interference ability of laser spot center detection and also improved the detection accuracy.

  15. Correlation filters for object detection in nonoverlapping background noise using a noisy reference image

    Science.gov (United States)

    Aguilar-González, Pablo Mario; Kober, Vitaly

    2009-08-01

    Classical correlation filters for object detection and location estimation are designed assuming that the appearance and the shape of the target are explicitly known. In this work we assume that the target is given at unknown coordinates in a reference image corrupted by additive noise. Optimal correlation filters, with respect to signal-to-noise ratio and peak-to-output energy, for object detection and location estimation are derived. Two mathematical models of observed images are used; the additive noise model for the reference image and the non-overlapping background model for the input scene. Computer simulation results obtained with the proposed filters are presented and compared with those of common correlation filters.

  16. White-throated sparrows alter songs differentially in response to chorusing anurans and other background noise.

    Science.gov (United States)

    Lenske, Ariel K; La, Van T

    2014-06-01

    Animals can use acoustic signals to attract mates and defend territories. As a consequence, background noise that interferes with signal transmission has the potential to reduce fitness, especially in birds that rely on song. While much research on bird song has investigated vocal flexibility in response to urban noise, weather and other birds, the possibility of inter-class acoustic competition from anurans has not been previously studied. Using sound recordings from central Ontario wetlands, we tested if white-throated sparrows (Zonotrichia albicolis) make short-term changes to their singing behaviour in response to chorusing spring peepers (Pseudacris crucifer), as well as to car noise, wind and other bird vocalizations. White-throated sparrow songs that were sung during the spring peeper chorus were shorter with higher minimum frequencies and narrower bandwidths resulting in reduced frequency overlap. Additionally, sparrows were less likely to sing when car noise and the vocalizations of other birds were present. These patterns suggest that birds use multiple adjustment strategies. This is the first report to demonstrate that birds may alter their songs differentially in response to different sources of noise. This article is part of a Special Issue entitled: insert SI title. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Acoustic noise background and sound transmission tests in a slurry line at the HYGAS Pilot Plant

    Energy Technology Data Exchange (ETDEWEB)

    Raptis, A.C.; Sheen, S.H.; Roach, P.D.; Mech, J.F.

    1979-01-01

    A State-of-the-Art report on instrumentation needs for coal conversion demonstration plants indicated that acoustic/ultrasonic techniques may be applied to measure two-phase flows found in coal conversion processes. Later theoretical feasibilities studies on the feasibility of acoustic/ultrasonic techniques to measure mass flow in coal conversion process streams were reported. These studies were based on limited theoretical and experimental results found in the literature. In the present work actual experimental results necessary to design a flowmeter for coal/liquid streams are presented. Acoustic data obtained from tests at the low pressure slurry line of the HYGAS char conversion pilot plant are presented. The data consist of the acoustic noise background and the sound transmission loss for the cases of 0, 18, and 33% char by weight in toluene and benzene. Spectra of noise background were scanned from 10 kHz to 1 MHz. Most acoustic energy of the noise background was shown to be below 500 kHz. Isolated acoustic events were also observed; such events represent either the acoustic resonance of the pipe or the resonant response of the transducer. Relative sound transmission losses were measured by the pitch catch pulse mode operation over the frequency range of 100 kHz to 1 MHz. Strong char concentration dependence with attenuation was observed. Results are discussed in terms of the sonar equation to indicate the feasibility of an ultrasonic or acoustic device applied to char conversion processes.

  18. 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.

  19. Impact of background noise and sentence complexity on processing demands during sentence comprehension

    Directory of Open Access Journals (Sweden)

    Dorothea eWendt

    2016-03-01

    Full Text Available 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. 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 working memory capacity showed increased pupil responses in the higher-level noise condition but rated sentence comprehension as being less effortful compared to participants with lower working memory capacity. 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.

  20. Impact of background noise and sentence complexity on cognitive processing demands

    DEFF Research Database (Denmark)

    Wendt, Dorothea; Dau, Torsten; Hjortkjær, Jens

    2015-01-01

    Speech comprehension in adverse listening conditions requires cognitive processingdemands. Processing demands can increase with acoustically degraded speech but also depend on linguistic aspects of the speech signal, such as syntactic complexity. In the present study, pupil dilations were recorded...... that increasing noise levels had a greater impact on the perceived difficulty than sentence complexity. In contrast, the processing of complex sentences resulted in greater and more prolonged pupil dilations. The results suggest that while pupil dilations may correlate with cognitive processing demands, acoustic...... in 19 normal-hearing participants while processing sentences that were either syntactically simple or complex and presented in either high- or low-level background noise. Furthermore, the participants were asked to rate the subjectively perceived difficulty of sentence comprehension. The results showed...

  1. Impact of background noise and sentence complexity on cognitive processing effort

    DEFF Research Database (Denmark)

    Wendt, Dorothea; Dau, Torsten; Hjortkjær, Jens

    2015-01-01

    Speech comprehension in adverse listening conditions requires cognitive pro- cessing demands. Processing demands can increase with acoustically degraded speech but also depend on linguistic aspects of the speech signal, such as syntactic complexity. In the present study, pupil dilations were...... showed that increasing noise levels had a greater impact on the perceived difficulty than sentence complexity. In contrast, the processing of complex sentences resulted in greater and more prolonged pupil dilations. The results suggest that while pupil dilations may correlate with cognitive processing...... recorded in 19 normal-hearing participants while processing sentences that were either syntactically simple or complex and presented in either high- or low-level background noise. Furthermore, the participants were asked to rate the sub- jectively perceived difficulty of sentence comprehension. The results...

  2. Effect of a Background Noise on the Acoustic Leak Detection Methodology for a SFR Steam Generator

    International Nuclear Information System (INIS)

    Kim, Tae-Joon; Jeong, Ji-Young; Kim, Jong-Man

    2007-01-01

    The protection of a water/steam leak into a sodium in the SFR SG at an early phase of a leak origin depends on a fast response and sensitivity of a leak detection system not to a response against the several kinds of noises. The subject in this study is to introduce a detection performance by using our developed acoustic leak detection methodology discriminated by a backpropagation neural network according to a preprocessing of the 1/6 Octave band analysis or 1/12 Octave band analysis and the x n method defined by us. It was used for the acoustic signals generated from the simulation works which are the noises of an artificial background such as a scratching, a hammering on a steel structure and so on. In a previous study, we showed that the performance of a LabVIEW tool embedded with the developed acoustic leak detection methodology detected the SWR leak signals

  3. 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

  4. 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.

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

    International Nuclear Information System (INIS)

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

    2012-01-01

    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.

  6. Notionally steady background noise acts primarily as a modulation masker of speech.

    Science.gov (United States)

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

    2012-07-01

    Stone et al. [J. Acoust. Soc Am. 130, 2874-2881 (2011)], using vocoder processing, showed that the envelope modulations of a notionally steady noise were more effective than the envelope energy as a masker of speech. Here the same effect is demonstrated using non-vocoded signals. Speech was filtered into 28 channels. A masker centered on each channel was added to the channel signal at a target-to-background ratio of -5 or -10 dB. Maskers were sinusoids or noise bands with bandwidth 1/3 or 1 ERB(N) (ERB(N) being the bandwidth of "normal" auditory filters), synthesized with Gaussian (GN) or low-noise (LNN) statistics. To minimize peripheral interactions between maskers, odd-numbered channels were presented to one ear and even to the other. Speech intelligibility was assessed in the presence of each "steady" masker and that masker 100% sinusoidally amplitude modulated (SAM) at 8 Hz. Intelligibility decreased with increasing envelope fluctuation of the maskers. Masking release, the difference in intelligibility between the SAM and its "steady" counterpart, increased with bandwidth from near-zero to around 50 percentage points for the 1-ERB(N) GN. It is concluded that the sinusoidal and GN maskers behaved primarily as energetic and modulation maskers, respectively.

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

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

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

    2016-10-01

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

  9. Office noise: Can headphones and masking sound attenuate distraction by background speech?

    Science.gov (United States)

    Jahncke, Helena; Björkeholm, Patrik; Marsh, John E; Odelius, Johan; Sörqvist, Patrik

    2016-11-22

    Background speech is one of the most disturbing noise sources at shared workplaces in terms of both annoyance and performance-related disruption. Therefore, it is important to identify techniques that can efficiently protect performance against distraction. It is also important that the techniques are perceived as satisfactory and are subjectively evaluated as effective in their capacity to reduce distraction. The aim of the current study was to compare three methods of attenuating distraction from background speech: masking a background voice with nature sound through headphones, masking a background voice with other voices through headphones and merely wearing headphones (without masking) as a way to attenuate the background sound. Quiet was deployed as a baseline condition. Thirty students participated in an experiment employing a repeated measures design. Performance (serial short-term memory) was impaired by background speech (1 voice), but this impairment was attenuated when the speech was masked - and in particular when it was masked by nature sound. Furthermore, perceived workload was lowest in the quiet condition and significantly higher in all other sound conditions. Notably, the headphones tested as a sound-attenuating device (i.e. without masking) did not protect against the effects of background speech on performance and subjective work load. Nature sound was the only masking condition that worked as a protector of performance, at least in the context of the serial recall task. However, despite the attenuation of distraction by nature sound, perceived workload was still high - suggesting that it is difficult to find a masker that is both effective and perceived as satisfactory.

  10. 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,…

  11. Intrinsic noise of a superheated droplet detector for neutron background measurements in massively shielded facilities

    Directory of Open Access Journals (Sweden)

    Fernandes Ana C.

    2017-01-01

    Full Text Available Superheated droplet detectors are a promising technique to the measurement of low-intensity neutron fields, as detectors can be rendered insensitive to minimum ionizing radiations. We report on the intrinsic neutron-induced signal of C2ClF5 devices fabricated by our group that originate from neutron- and alpha-emitting impurities in the detector constituents. The neutron background was calculated via Monte Carlo simulations using the MCNPX-PoliMi code in order to extract the recoil distributions following neutron interaction with the atoms of the superheated liquid. Various nuclear techniques were employed to characterise the detector materials with respect to source isotopes (238U, 232Th and 147Sm for the normalisation of the simulations and also light elements (B, Li having high (α, n neutron production yields. We derived a background signal of ~10-3 cts/day in a 1 liter detector of 1-3 wt.% C2ClF5, corresponding to a detection limit in the order of 10-8 n cm-2s-1. Direct measurements in a massively shielded underground facility for dark matter search have confirmed this result. With the borosilicate detector containers found to be the dominant background source in current detectors, possibilities for further noise reduction by ~2 orders of magnitude based on selected container materials are discussed.

  12. Background electromagnetic noise characterization: the role of external and internal Earth sources

    Directory of Open Access Journals (Sweden)

    Antonio Meloni

    2015-07-01

    Full Text Available The Earth is surrounded by the ionosphere and magnetosphere that can roughly be seen schematically as two concentric shells. These two composed and inhomogeneous structured shells around the Earth selectively affect electromagnetic (EM waves propagation. Both ionosphere and magnetosphere interact also with particles and waves coming from external sources, generating electromagnetic phenomena that in turn might become sources of EM waves. Conversely, EM waves generated inside the ionosphere remain confined at various altitudes in this region, up to a so-called critical frequency limit, depending on frequency, EM waves can escape out of the ionosphere and magnetosphere or get through. The EM waves generated inside the magnetospheric cavity mainly originate as a result of the electrical activity in the atmosphere. It is well known that also man-made sources, now widely spread on Earth, are a fundamental source of EM waves; however, excluding certain frequencies employed in power distribution and communication, man-made noise can be dominant only at local scale, near their source. According to recent studies, EM waves are also generated in the Earth’s lithosphere; these waves were sometimes associated with earthquake activity showing, on the Earth’s surface, intensities that are generally orders of magnitude below the background EM noise. In this review paper, we illustrate EM waves of natural origin and discuss their characterization in order to try discriminate those of lithospheric origin detectable at or near the Earth’s surface.

  13. Wavelet Co-movement Significance Testing with Respect to Gaussian White Noise Background

    Directory of Open Access Journals (Sweden)

    Poměnková Jitka

    2018-01-01

    Full Text Available The paper deals with significance testing of time series co-movement measured via wavelet analysis, namely via the wavelet cross-spectra. This technique is very popular for its better time resolution compare to other techniques. Such approach put in evidence the existence of both long-run and short-run co-movement. In order to have better predictive power it is suitable to support and validate obtained results via some testing approach. We investigate the test of wavelet power cross-spectrum with respect to the Gaussian white noise background with the use of the Bessel function. Our experiment is performed on real data, i.e. seasonally adjusted quarterly data of gross domestic product of the United Kingdom, Korea and G7 countries. To validate the test results we perform Monte Carlo simulation. We describe the advantages and disadvantages of both approaches and formulate recommendations for its using.

  14. Acceptance of background noise, working memory capacity, and auditory evoked potentials in subjects with normal hearing.

    Science.gov (United States)

    Brännström, K Jonas; Zunic, Edita; Borovac, Aida; Ibertsson, Tina

    2012-01-01

    The acceptable noise level (ANL) test is a method for quantifying the amount of background noise that subjects accept when listening to speech. Large variations in ANL have been seen between normal-hearing subjects and between studies of normal-hearing subjects, but few explanatory variables have been identified. To explore a possible relationship between a Swedish version of the ANL test, working memory capacity (WMC), and auditory evoked potentials (AEPs). ANL, WMC, and AEP were tested in a counterbalanced order across subjects. Twenty-one normal-hearing subjects participated in the study (14 females and 7 males; aged 20-39 yr with an average of 25.7 yr). Reported data consists of age, pure-tone average (PTA), most comfortable level (MCL), background noise level (BNL), ANL (i.e., MCL - BNL), AEP latencies, AEP amplitudes, and WMC. Spearman's rank correlation coefficient was calculated between the collected variables to investigate associations. A principal component analysis (PCA) with Varimax rotation was conducted on the collected variables to explore underlying factors and estimate interactions between the tested variables. Subjects were also pooled into two groups depending on their results on the WMC test, one group with a score lower than the average and one with a score higher than the average. Comparisons between these two groups were made using the Mann-Whitney U-test with Bonferroni correction for multiple comparisons. A negative association was found between ANL and WMC but not between AEP and ANL or WMC. Furthermore, ANL is derived from MCL and BNL, and a significant positive association was found between BNL and WMC. However, no significant associations were seen between AEP latencies and amplitudes and the demographic variables, MCL, and BNL. The PCA identified two underlying factors: One that contained MCL, BNL, ANL, and WMC and another that contained latency for wave Na and amplitudes for waves V and Na-Pa. Using the variables in the first factor

  15. Chemical Source Localization Fusing Concentration Information in the Presence of Chemical Background Noise.

    Science.gov (United States)

    Pomareda, Víctor; Magrans, Rudys; Jiménez-Soto, Juan M; Martínez, Dani; Tresánchez, Marcel; Burgués, Javier; Palacín, Jordi; Marco, Santiago

    2017-04-20

    We present the estimation of a likelihood map for the location of the source of a chemical plume dispersed under atmospheric turbulence under uniform wind conditions. The main contribution of this work is to extend previous proposals based on Bayesian inference with binary detections to the use of concentration information while at the same time being robust against the presence of background chemical noise. For that, the algorithm builds a background model with robust statistics measurements to assess the posterior probability that a given chemical concentration reading comes from the background or from a source emitting at a distance with a specific release rate. In addition, our algorithm allows multiple mobile gas sensors to be used. Ten realistic simulations and ten real data experiments are used for evaluation purposes. For the simulations, we have supposed that sensors are mounted on cars which do not have among its main tasks navigating toward the source. To collect the real dataset, a special arena with induced wind is built, and an autonomous vehicle equipped with several sensors, including a photo ionization detector (PID) for sensing chemical concentration, is used. Simulation results show that our algorithm, provides a better estimation of the source location even for a low background level that benefits the performance of binary version. The improvement is clear for the synthetic data while for real data the estimation is only slightly better, probably because our exploration arena is not able to provide uniform wind conditions. Finally, an estimation of the computational cost of the algorithmic proposal is presented.

  16. Background- and simulated leak-noise measurements on ASB-loop, KNK II- and SNR 300-steam generators

    International Nuclear Information System (INIS)

    Voss, J.; Arnaoutis, N.; Foerster, K.; Moellerfeld, H.

    1990-01-01

    During several leak propagation experiments in the ASB sodium loop noise measurements were performed showing the acoustic behaviour of evoluting leaks in a tube bundle section under sodium. Effects like self evolution, secondary leaks and tube ruptures by overheating occurred during these tests and were reflected in the course of acoustic signals. In one of the KNK II steam generators simulated leak noise was detected against background noise throughout the operating power range. Experimental arrangements and results are described. In SNR 300 all of the SGUs are equipped with waveguides and some with accelerometers for background noise measurements. First measurement under isothermal conditions were performed in the past. A gas injection device for acoustic leak simulation is under construction. The design of the experimental acoustic system and first results are presented. (author). 1 ref., 21 figs, 2 tabs

  17. Characterization of background noise in capture-based targeted sequencing data.

    Science.gov (United States)

    Park, Gahee; Park, Joo Kyung; Shin, Seung-Ho; Jeon, Hyo-Jeong; Kim, Nayoung K D; Kim, Yeon Jeong; Shin, Hyun-Tae; Lee, Eunjin; Lee, Kwang Hyuck; Son, Dae-Soon; Park, Woong-Yang; Park, Donghyun

    2017-07-21

    Targeted deep sequencing is increasingly used to detect low-allelic fraction variants; it is therefore essential that errors that constitute baseline noise and impose a practical limit on detection are characterized. In the present study, we systematically evaluate the extent to which errors are incurred during specific steps of the capture-based targeted sequencing process. We removed most sequencing artifacts by filtering out low-quality bases and then analyze the remaining background noise. By recognizing that plasma DNA is naturally fragmented to be of a size comparable to that of mono-nucleosomal DNA, we were able to identify and characterize errors that are specifically associated with acoustic shearing. Two-thirds of C:G > A:T errors and one quarter of C:G > G:C errors were attributed to the oxidation of guanine during acoustic shearing, and this was further validated by comparative experiments conducted under different shearing conditions. The acoustic shearing step also causes A > G and A > T substitutions localized to the end bases of sheared DNA fragments, indicating a probable association of these errors with DNA breakage. Finally, the hybrid selection step contributes to one-third of the remaining C:G > A:T and one-fifth of the C > T errors. The results of this study provide a comprehensive summary of various errors incurred during targeted deep sequencing, and their underlying causes. This information will be invaluable to drive technical improvements in this sequencing method, and may increase the future usage of targeted deep sequencing methods for low-allelic fraction variant detection.

  18. Is children's listening effort in background noise influenced by the speaker's voice quality?

    Science.gov (United States)

    Sahlén, Birgitta; Haake, Magnus; von Lochow, Heike; Holm, Lucas; Kastberg, Tobias; Brännström, K Jonas; Lyberg-Åhlander, Viveka

    2018-07-01

    The present study aims at exploring the influence of voice quality on listening effort in children performing a language comprehension test with sentences of increasing difficulty. Listening effort is explored in relation to gender ( = cisgender). The study has a between-groups design. Ninety-three mainstreamed children aged 8;2 to 9;3 with typical language development participated. The children were randomly assigned to two groups (n = 46/47) with equal allocation of boys and girls and for the analysis to four groups depending of gender and voice condition. Working memory capacity and executive functions were tested in quiet. A digital version of a language comprehension test (the TROG-2) was used to measure the effect of voice quality on listening effort, measured as response time in a forced-choice paradigm. The groups listened to sentences through recordings of the same female voice, one group with a typical voice and one with a dysphonic voice, both in competing multi-talker babble noise. Response times were logged after a time buffer between the sentence-ending and indication of response. There was a significant increase in response times with increased task difficulty and response times between the two voice conditions differed significantly. The girls in the dysphonic condition were slower with increasing task difficulty. A dysphonic voice clearly adds to the noise burden and listening effort is greater in girls than in boys when the teacher speaks with dysphonic voice in a noisy background. These findings might mirror gender differences as for coping strategies in challenging contexts and have important implications for education.

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

    Science.gov (United States)

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

    2017-09-01

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

  20. Measurement of acoustic background noise and simulated impact sound in BWR

    International Nuclear Information System (INIS)

    Izumi, Shigeru; Michiguchi, Yoshihiro; Yamada, Kimio; Hamada, Kenjiro; Sekido, Yoji; Segawa, Motomichi.

    1984-01-01

    In order to develop a method for detecting and locating metallic loose parts in BWRs, sound properties were studied. Five acoustic sensors were attached to the BWR pressure vessel and simulated impacts were given to the vessel by hitting it with a hammer. Background noise during the actual plant operation and the impact sound were measured and analyzed. The following results were obtained: (1) Signals with S/N of five or more for impacts with an energy of 0.2J at full power plant operation were obtained by accelerometers located within 6 m from the impact positions. (2) Arrival time and amplitude of the impact signals showed a good reproducibility for the same impact position. On the other hand, there was a poor relationship between time or amplitude information and acoustic path length. This fact suggested that there is little chance for impact sound location into reality by analytical methods such as triangulation. It will be one of the solution for the acculate location to make use of data for reference impacts. (author)

  1. 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.

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

    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.

  3. 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.

  4. Effects of background noise on inter-trial phase coherence and auditory N1-P2 responses to speech stimuli.

    Science.gov (United States)

    Koerner, Tess K; Zhang, Yang

    2015-10-01

    This study investigated the effects of a speech-babble background noise on inter-trial phase coherence (ITPC, also referred to as phase locking value (PLV)) and auditory event-related responses (AERP) to speech sounds. Specifically, we analyzed EEG data from 11 normal hearing subjects to examine whether ITPC can predict noise-induced variations in the obligatory N1-P2 complex response. N1-P2 amplitude and latency data were obtained for the /bu/syllable in quiet and noise listening conditions. ITPC data in delta, theta, and alpha frequency bands were calculated for the N1-P2 responses in the two passive listening conditions. Consistent with previous studies, background noise produced significant amplitude reduction and latency increase in N1 and P2, which were accompanied by significant ITPC decreases in all the three frequency bands. Correlation analyses further revealed that variations in ITPC were able to predict the amplitude and latency variations in N1-P2. The results suggest that trial-by-trial analysis of cortical neural synchrony is a valuable tool in understanding the modulatory effects of background noise on AERP measures. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. An analysis of seismic background noise variation and evaluation of detection capability of Keskin Array (BRTR PS-43) in Turkey

    Science.gov (United States)

    Bakir, M. E.; Ozel, N. M.; Semin, K. U.

    2011-12-01

    Bogazici University, Kandilli Observatory and Earthquake Research Institute (KOERI) is currently operating the Keskin seismic array (BRTR-PS 43) located in town Keskin, providing real-time data to IDC. The instrumentaion of seismic array includes six short period borehole seismometers and one broadband borehole seismometer. The seismic background noise variation of Keskin array are studied in order to estimate the local and regional event detection capability in the frequency range from 1 Hz to 10 Hz. The Power density spectrum and also probability density function of Keskin array data were computed for seasonal and diurnal noise variations between 2008 and 2010. The computation will be extended to cover the period between 2005 and 2008. We attempt to determine the precise frequency characteristics of the background noise, which will help us to assess the station sensitivity. Minimum detectable magnitude versus distance for Keskin seismic array will be analyzed based on the seismic noise analysis. Detailed analysis results of seismic background noise and detection capability will be presented by this research.

  6. The Impact of Age, Background Noise, Semantic Ambiguity, and Hearing Loss on Recognition Memory for Spoken Sentences

    Science.gov (United States)

    Koeritzer, Margaret A.; Rogers, Chad S.; Van Engen, Kristin J.; Peelle, Jonathan E.

    2018-01-01

    Purpose: The goal of this study was to determine how background noise, linguistic properties of spoken sentences, and listener abilities (hearing sensitivity and verbal working memory) affect cognitive demand during auditory sentence comprehension. Method: We tested 30 young adults and 30 older adults. Participants heard lists of sentences in…

  7. Estimation of Spectral Exponent Parameter of 1/f Process in Additive White Background Noise

    Directory of Open Access Journals (Sweden)

    Semih Ergintav

    2007-01-01

    Full Text Available An extension to the wavelet-based method for the estimation of the spectral exponent, γ, in a 1/fγ process and in the presence of additive white noise is proposed. The approach is based on eliminating the effect of white noise by a simple difference operation constructed on the wavelet spectrum. The γ parameter is estimated as the slope of a linear function. It is shown by simulations that the proposed method gives reliable results. Global positioning system (GPS time-series noise is analyzed and the results provide experimental verification of the proposed method.

  8. 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.

  9. 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.

  10. Comparing the effects of aging and background noise on short-term memory performance.

    Science.gov (United States)

    Murphy, Dana R; Craik, Fergus I M; Li, Karen Z H; Schneider, Bruce A

    2000-06-01

    Paired associate recall was tested as a function of serial position for younger and older adults for five word pairs presented aurally in quiet and in noise. In Experiment 1, the addition of noise adversely affected recall in young adults, but only in the early serial positions. Experiments 2 and 3 suggested that the recall of older adults listening to the words in quiet was nearly equivalent to that of younger adults listening in noise. In Experiment 4, we determined the signal-to-noise ratio (S/N) such that, on average, younger and older adults were able to correctly hear the same percentage of words when words were presented one at a time in noise. In Experiment 5, younger adults were tested under this S/N. Compared with older adults from Experiment 3, younger adults in this experiment recalled more words at all serial positions. The results are interpreted as showing that encoding in secondary memory is impaired by aging and noise either as a function of degraded sensory representations, or as a function of reduced processing resources.

  11. 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

  12. Sleep disturbance caused by meaningful sounds and the effect of background noise

    Science.gov (United States)

    Namba, Seiichiro; Kuwano, Sonoko; Okamoto, Takehisa

    2004-10-01

    To study noise-induced sleep disturbance, a new procedure called "noise interrupted method"has been developed. The experiment is conducted in the bedroom of the house of each subject. The sounds are reproduced with a mini-disk player which has an automatic reverse function. If the sound is disturbing and subjects cannot sleep, they are allowed to switch off the sound 1 h after they start to try to sleep. This switch off (noise interrupted behavior) is an important index of sleep disturbance. Next morning they fill in a questionnaire in which quality of sleep, disturbance of sounds, the time when they switched off the sound, etc. are asked. The results showed a good relationship between L and the percentages of the subjects who could not sleep in an hour and between L and the disturbance reported in the questionnaire. This suggests that this method is a useful tool to measure the sleep disturbance caused by noise under well-controlled conditions.

  13. Modeling Speech Level as a Function of Background Noise Level and Talker-to-Listener Distance for Talkers Wearing Hearing Protection Devices

    DEFF Research Database (Denmark)

    Bouserhal, Rachel E.; Bockstael, Annelies; MacDonald, Ewen

    2017-01-01

    -to-listener distance, and background noise level for occluded talkers could eventually be incorporated with radio protocols to transmit verbal communication only to an intended set of listeners within a given spatial range—this range being dependent on the changes in speech level and background noise level....

  14. Modeling Speech Level as a Function of Background Noise Level and Talker-to-Listener Distance for Talkers Wearing Hearing Protection Devices

    Science.gov (United States)

    Bouserhal, Rachel E.; Bockstael, Annelies; MacDonald, Ewen; Falk, Tiago H.; Voix, Jérémie

    2017-01-01

    Purpose: Studying the variations in speech levels with changing background noise level and talker-to-listener distance for talkers wearing hearing protection devices (HPDs) can aid in understanding communication in background noise. Method: Speech was recorded using an intra-aural HPD from 12 different talkers at 5 different distances in 3…

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

    OpenAIRE

    Niklas eRönnberg; Niklas eRönnberg; Mary eRudner; Mary eRudner; Thomas eLunner; Thomas eLunner; Thomas eLunner; Thomas eLunner; Stefan eStenfelt; Stefan eStenfelt

    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 t...

  16. Effects of Age-Related Hearing Loss and Background Noise on Neuromagnetic Activityfrom Auditory Cortex

    Directory of Open Access Journals (Sweden)

    Claude eAlain

    2014-01-01

    Full Text Available Aging is often accompanied by hearing loss, which impacts how sounds are processed and represented along the ascending auditory pathways and within the auditory cortices. Here, we assess the impact of mild binaural hearing loss on the older adults’ ability to both process complex sounds embedded in noise and segregate a mistuned harmonic in an otherwise periodic stimulus. We measured auditory evoked fields (AEFs using magnetoencephalography while participants were presented with complex tones that had either all harmonics in tune or had the third harmonic mistuned by 4 or 16% of its original value. The tones (75 dB sound pressure level, SPL were presented without, with low (45 dBA, SPL or with moderate (65 dBA SPL Gaussian noise. For each participant, we modeled the AEFs with a pair of dipoles in the superior temporal plane. We then examined the effects of hearing loss and noise on the amplitude and latency of the resulting source waveforms. In the present study, results revealed that similar noise-induced increases in N1m were present in older adults with and without hearing loss. Our results also showed that the P1m amplitude was larger in the hearing impaired than normal-hearing adults. In addition, the object-related negativity (ORN elicited by the mistuned harmonic was larger in hearing impaired listeners. The enhanced P1m and ORN amplitude in the hearing impaired older adults suggests that hearing loss increased neural excitability in auditory cortices, which could be related to deficits in inhibitory control.

  17. 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.

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

    Directory of Open Access Journals (Sweden)

    Niklas eRönnberg

    2014-12-01

    Full Text Available 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 MLL. 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.

  19. 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 ...

  20. Label-free fluorescence strategy for sensitive detection of adenosine triphosphate using a loop DNA probe with low background noise.

    Science.gov (United States)

    Lin, Chunshui; Cai, Zhixiong; Wang, Yiru; Zhu, Zhi; Yang, Chaoyong James; Chen, Xi

    2014-07-15

    A simple, rapid, label-free, and ultrasensitive fluorescence strategy for adenosine triphosphate (ATP) detection was developed using a loop DNA probe with low background noise. In this strategy, a loop DNA probe, which is the substrate for both ligation and digestion enzyme reaction, was designed. SYBR green I (SG I), a double-stranded specific dye, was applied for the readout fluorescence signal. Exonuclease I (Exo I) and exonuclease III (Exo III), sequence-independent nucleases, were selected to digest the loop DNA probe in order to minimize the background fluorescence signal. As a result, in the absence of ATP, the loop DNA was completely digested by Exo I and Exo III, leading to low background fluorescence owing to the weak electrostatic interaction between SG I and mononucleotides. On the other hand, ATP induced the ligation of the nicking site, and the sealed loop DNA resisted the digestion of Exo I and ExoIII, resulting in a remarkable increase of fluorescence response. Upon background noise reduction, the sensitivity of the ATP determination was improved significantly, and the detection limitation was found to be 1.2 pM, which is much lower than that in almost all the previously reported methods. This strategy has promise for wide application in the determination of ATP.

  1. Impact of background light induced shot noise in high-speed full-duplex indoor optical wireless communication systems.

    Science.gov (United States)

    Wang, Ke; Nirmalathas, Ampalavanapillai; Lim, Christina; Skafidas, Efstratios

    2011-10-24

    The use of infrared radiation to provide high speed indoor wireless communication has attracted considerable attention for over a decade. In previous studies we proposed a novel full-duplex indoor optical wireless communication system with high-speed data transmission and limited mobility can be provided to users. When it is incorporated with localization function, gigabit mobile communication can be provided over the entire room. In this paper we theoretically analyze the limiting factor of our proposed system - background light induced shot noise. A theoretical model that allows the receiver sensitivity and the corresponding power penalty is proposed and the model is validated by experiments. Experimental results show that for both down-link and up-link transmission the background light will result in several dB power penalty and it is more dominant in lower speed links. As the bit rate increases, the preamplifier induced noise becomes larger and eventually dominates the noise process. © 2011 Optical Society of America

  2. High dynamic range low-noise focal plane readout for VLWIR applications implemented with current mode background subtraction

    Science.gov (United States)

    Yang, Guang; Sun, Chao; Shaw, Timothy; Wrigley, Chris; Peddada, Pavani; Blazejewski, Edward R.; Pain, Bedabrata

    1998-09-01

    Design and operation of a low noise CMOS focal pa;ne readout circuit with ultra-high charge handling capacity is presented. Designed for high-background, VLWIR detector readout, each readout unit cell use an accurate dynamic current memory for automatic subtraction of the dark pedestal in current domain enabling measurement of small signals 85 dB below the dark level. The redout circuit operates with low-power dissipation, high linearity, and is capable of handling pedestal currents up to 300 nA. Measurements indicate an effective charge handling capacity of over 5 X 10(superscript 9) charges/pixel with less than 10(superscript 5) electrons of input referred noise.

  3. The role of binary mask patterns in automatic speech recognition in background noise.

    Science.gov (United States)

    Narayanan, Arun; Wang, DeLiang

    2013-05-01

    Processing noisy signals using the ideal binary mask improves automatic speech recognition (ASR) performance. This paper presents the first study that investigates the role of binary mask patterns in ASR under various noises, signal-to-noise ratios (SNRs), and vocabulary sizes. Binary masks are computed either by comparing the SNR within a time-frequency unit of a mixture signal with a local criterion (LC), or by comparing the local target energy with the long-term average spectral energy of speech. ASR results show that (1) akin to human speech recognition, binary masking significantly improves ASR performance even when the SNR is as low as -60 dB; (2) the ASR performance profiles are qualitatively similar to those obtained in human intelligibility experiments; (3) the difference between the LC and mixture SNR is more correlated to the recognition accuracy than LC; (4) LC at which the performance peaks is lower than 0 dB, which is the threshold that maximizes the SNR gain of processed signals. This broad agreement with human performance is rather surprising. The results also indicate that maximizing the SNR gain is probably not an appropriate goal for improving either human or machine recognition of noisy speech.

  4. Contribution of resolved and unresolved harmonic regions to brainstem speech-evoked responses in quiet and in background noise

    Directory of Open Access Journals (Sweden)

    M. Laroche

    2011-03-01

    Full Text Available Speech auditory brainstem responses (speech ABR reflect activity that is phase-locked to the harmonics of the fundamental frequency (F0 up to at least the first formant (F1. Recent evidence suggests that responses at F0 in the presence of noise are more robust than responses at F1, and are also dissociated in some learning-impaired children. Peripheral auditory processing can be broadly divided into resolved and unresolved harmonic regions. This study investigates the contribution of these two regions to the speech ABR, and their susceptibility to noise. We recorded, in quiet and in background white noise, evoked responses in twelve normal hearing adults in response to three variants of a synthetic vowel: i Allformants, which contains all first three formants, ii F1Only, which is dominated by resolved harmonics, and iii F2&F3Only, which is dominated by unresolved harmonics. There were no statistically significant differences in the response at F0 due to the three variants of the stimulus in quiet, nor did the noise affect this response with the Allformants and F1Only variants. On the other hand, the response at F0 with the F2&F3Only variant was significantly weaker in noise than with the two other variants (p<0.001. With the response at F1, there was no difference with the Allformants and F1Only variants in quiet, but was expectedly weaker with the F2&F3Only variant (p<0.01. The addition of noise significantly weakened the response at F1 with the F1Only variant (p<0.05, but this weakening only tended towards significance with the Allformants variant (p=0.07. The results of this study indicate that resolved and unresolved harmonics are processed in different but interacting pathways that converge in the upper brainstem. The results also support earlier work on the differential susceptibility of responses at F0 and F1 to added noise.

  5. 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.

  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

    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...... index (STI) needs to be improved. The impact of the reverberation time (RT), the distribution of the absorptive materials and the introduction of a screen on STI are discussed briefly .However, these objective parameters have to be assessed through subjective judgement. Auralizations of the multi source...... 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...

  7. Acoustic Event Location and Background Noise Characterization on a Free Flying Infrasound Sensor Network in the Stratosphere

    Science.gov (United States)

    Bowman, Daniel C.; Albert, Sarah A.

    2018-02-01

    A variety of Earth surface and atmospheric sources generate low frequency sound waves that can travel great distances. Despite a rich history of ground-based sensor studies, very few experiments have investigated the prospects of free floating microphone arrays at high altitudes. However, recent initiatives have shown that such networks have very low background noise and may sample an acoustic wave field that is fundamentally different than that at Earth's surface. The experiments have been limited to at most two stations at altitude, making acoustic event detection and localization difficult. We describe the deployment of four drifting microphone stations at altitudes between 21 and 24 km above sea level. The stations detected one of two regional ground-based chemical explosions as well as the ocean microbarom while traveling almost 500 km across the American Southwest. The explosion signal consisted of multiple arrivals; signal amplitudes did not correlate with sensor elevation or source range. The waveforms and propagation patterns suggest interactions with gravity waves in the 35-45 km altitude. A sparse network method that employed curved wave front corrections was able to determine the backazimuth from the free flying network to the acoustic source. Episodic signals similar to those seen on previous flights in the same region were noted, but their source remains unclear. Background noise levels were commensurate with those on infrasound stations in the International Monitoring System below 2 seconds.

  8. Autonomous low-noise system for broadband measurements of the cosmic microwave background radiation

    Science.gov (United States)

    Dekoulis, George

    2009-05-01

    This paper describes the digital side implementation of a new suborbital experiment for the measurement of broadband radiation emissions of the Cosmic Microwave Background (CMB) anisotropy. The system has been used in campaign mode for initial mapping of the galactic radiation power received at a single frequency. The recorded galactic sky map images are subsequently being used to forecast the emitted radiation at neighboring frequencies. A planned second campaign will verify the prediction algorithms efficiency in an autonomous manner. The system has reached an advanced stage in terms of hardware and software combined operation and intelligence, where other Space Physics measurements are performed autonomously depending on the burst event under investigation. The system has been built in a modular manner to expedite hardware and software upgrades. Such an upgrade has recently occurred mainly to expand the frequency range of space observations.

  9. CS2 analysis in presence of non-Gaussian background noise - Effect on traditional estimators and resilience of log-envelope indicators

    Science.gov (United States)

    Borghesani, P.; Antoni, J.

    2017-06-01

    Second-order cyclostationary (CS2) analysis has become popular in the field of machine diagnostics and a series of digital signal processing techniques have been developed to extract CS2 components from the background noise. Among those techniques, squared envelope spectrum (SES) and cyclic modulation spectrum (CMS) have gained popularity thanks to their high computational efficiency and simple implementation. The effectiveness of CMS and SES has been previously quantified based on the hypothesis of Gaussian background noise and has led to statistical tests for the presence of CS2 peaks in squared envelope spectra and cyclic modulation spectra. However a recently established link of CMS with SES and of SES with kurtosis has exposed a potential weakness of those indicators in the case of highly leptokurtic background noise. This case is often present in practice when the machine is subjected to highly impulsive phenomena, either due to harsh operating conditions or to electric noise generated by power electronics and captured by the sensor. This study investigates and quantifies for the first time the effect of leptokurtic noise on the capabilities of SES and CMS, by analysing three progressively harsh situations: high kurtosis, infinite kurtosis and alpha-stable background noise (for which even first and second-order moments are not defined). Then the resilience of a recently proposed family of CS2 indicators, based on the log-envelope, is verified analytically, numerically and experimentally in the case of highly leptokurtic noise.

  10. 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

  11. Application of upconversion luminescent-magnetic microbeads with weak background noise and facile separation in ochratoxin A detection

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Zhenyu, E-mail: liaozy08@163.com [Tianjin Product Quality Inspection Technology Research Institute, The National Center of Supervision and Inspection for Quality of Food (China); Zhang, Ying [Tianjin University, School of Life Sciences, Tianjin Engineering Center of Micro-Nano Biomaterials and Detection-Treatment Technology (China); Su, Lin [Tianjin Medical University Eye Hospital, Eye Institute and School of Optometry and Ophthalmology (China); Chang, Jin; Wang, Hanjie, E-mail: wanghj@tju.edu.cn [Tianjin University, School of Life Sciences, Tianjin Engineering Center of Micro-Nano Biomaterials and Detection-Treatment Technology (China)

    2017-02-15

    Ochratoxin A (OTA), the most harmful and abundant ochratoxin, is chemically stable and commonly existed in foodstuffs. In this work, upconversion luminescent-magnetic microbeads (UCLMMs) -based cytometric bead array for OTA detection with a less reagent consumption and high sensitivity has been established and optimized. In UCLMMs, upconversion nanocrystals (UCNs) for optical code present a weak background noise and no spectral cross talk between the encoding signals and target labels under two excitation conditions to improve detection sensitivity. While the superparamagnetic Fe{sub 3}O{sub 4} nanoparticles (Fe{sub 3}O{sub 4} NPs) aim for rapid analysis. The results show that the developed method has a sensitivity of 9.553 ppt below HPLC with a 50-μL sample and can be completed in <2 h with good accuracy and high reproducibility. Therefore, different colors of UCLMMs will become a promising assay platform for multiple mycotoxins after further improvement.

  12. 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

  13. 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.

  14. The Influence of Geography and Geology on Seismic Background Noise Levels Across the United States as Revealed by the Transportable Array

    Science.gov (United States)

    Anthony, R. E.; Ringler, A. T.; Holland, A. A.; Wilson, D. C.

    2017-12-01

    The EarthScope USArray Transportable Array (TA) has now covered the US with 3-component broadband seismometers at approximately 70 km station spacing and deployment durations of approximately 2 years. This unprecedented coverage, combined with high-quality and near homogenous installation techniques, offers a novel dataset in which to characterize spatially varying levels of background seismic noise across the United States. We present background noise maps in period bands of interest to earthquake and imaging seismology across the US (lower 48 states and Alaska). Early results from the contiguous 48 states demonstrate that ambient noise levels within the body wave period band (1-5 s) vary by > 20 dB (rel. 1 (m/s2)2/Hz) with the highest noise levels occurring at stations located within sedimentary basins and lowest within the mountain ranges of the Western US. Additionally, stations around the Great Lakes observe heightened noise levels in this band beyond the aforementioned basin amplification. We attribute this observation to local swell activity in the Great Lakes generating short-period microseism signals. This suggests that lake-generated microseisms may be a significant source of noise for Alaskan deployments situated in close proximity to lakes to facilitate float plane access. We further investigate how basin amplification and short-period lake microseism signals may noticeably impact detection and signal-to-noise of teleseismic body wave signals during certain time periods. At longer-periods (> 20 s), we generally observe larger noise levels on the horizontal components of stations situated in basins or on soft sediment, likely caused by locally induced tilt of the sensor. We will present similar analysis from the initial Alaska TA dataset to quantitatively assess how utilization of posthole sensors affects signal-to-noise for the long-period horizontal wavefield.

  15. 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)

    Piquemal, F.

    1994-05-01

    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 10 25 years for 100 Mo). 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 214 Bi 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)

  16. Failing to Get the Gist of What’s Being Said: Background Noise Impairs Higher Order Cognitive Processing

    OpenAIRE

    John Everett Marsh; John Everett Marsh; Robert eLjung; Anatole eNöstl; Emma eThreadgold; Tom A Campbell

    2015-01-01

    A dynamic interplay is known to exist between auditory processing and human cognition. For example, prior investigations of speech-in-noise have revealed there is more to learning than just listening: Even if all words within a spoken list correctly heard in noise, later memory for those words is typically impoverished. At such low signal-to-noise ratios when listeners could identify words, those participants could not necessarily remember those words. These investigations supported a view th...

  17. Speech perception for adult cochlear implant recipients in a realistic background noise: effectiveness of preprocessing strategies and external options for improving speech recognition in noise.

    Science.gov (United States)

    Gifford, René H; Revit, Lawrence J

    2010-01-01

    Although cochlear implant patients are achieving increasingly higher levels of performance, speech perception in noise continues to be problematic. The newest generations of implant speech processors are equipped with preprocessing and/or external accessories that are purported to improve listening in noise. Most speech perception measures in the clinical setting, however, do not provide a close approximation to real-world listening environments. To assess speech perception for adult cochlear implant recipients in the presence of a realistic restaurant simulation generated by an eight-loudspeaker (R-SPACE) array in order to determine whether commercially available preprocessing strategies and/or external accessories yield improved sentence recognition in noise. Single-subject, repeated-measures design with two groups of participants: Advanced Bionics and Cochlear Corporation recipients. Thirty-four subjects, ranging in age from 18 to 90 yr (mean 54.5 yr), participated in this prospective study. Fourteen subjects were Advanced Bionics recipients, and 20 subjects were Cochlear Corporation recipients. Speech reception thresholds (SRTs) in semidiffuse restaurant noise originating from an eight-loudspeaker array were assessed with the subjects' preferred listening programs as well as with the addition of either Beam preprocessing (Cochlear Corporation) or the T-Mic accessory option (Advanced Bionics). In Experiment 1, adaptive SRTs with the Hearing in Noise Test sentences were obtained for all 34 subjects. For Cochlear Corporation recipients, SRTs were obtained with their preferred everyday listening program as well as with the addition of Focus preprocessing. For Advanced Bionics recipients, SRTs were obtained with the integrated behind-the-ear (BTE) mic as well as with the T-Mic. Statistical analysis using a repeated-measures analysis of variance (ANOVA) evaluated the effects of the preprocessing strategy or external accessory in reducing the SRT in noise. In addition

  18. Failing to get the gist of what's being said: background noise impairs higher-order cognitive processing

    OpenAIRE

    Marsh, John E.; Ljung, Robert; N?stl, Anatole; Threadgold, Emma; Campbell, Tom A.

    2015-01-01

    A dynamic interplay is known to exist between auditory processing and human cognition. For example, prior investigations of speech-in-noise have revealed there is more to learning than just listening: Even if all words within a spoken list are correctly heard in noise, later memory for those words is typically impoverished. These investigations supported a view that there is a "gap" between the intelligibility of speech and memory for that speech. Here, the notion was that this gap between sp...

  19. Suppression of the four-wave-mixing background noise in a quantum memory retrieval process by channel blocking

    Science.gov (United States)

    Zhang, Kai; Guo, Jinxian; Chen, L. Q.; Yuan, Chunhua; Ou, Z. Y.; Zhang, Weiping

    2014-09-01

    In a quantum memory scheme with the Raman process, the read process encounters noise from four-wave mixing (FWM), which can destroy the nonclassical properties of the generated quantum fields. Here we demonstrate experimentally that the noise from FWM can be greatly suppressed by simply reducing the FWM transition channels with a circularly polarized read beam while at the same time retaining relatively high retrieval efficiency.

  20. Failing to Get the Gist of What’s Being Said: Background Noise Impairs Higher Order Cognitive Processing

    Directory of Open Access Journals (Sweden)

    John Everett Marsh

    2015-05-01

    Full Text Available A dynamic interplay is known to exist between auditory processing and human cognition. For example, prior investigations of speech-in-noise have revealed there is more to learning than just listening: Even if all words within a spoken list correctly heard in noise, later memory for those words is typically impoverished. At such low signal-to-noise ratios when listeners could identify words, those participants could not necessarily remember those words. These investigations supported a view that there is a gap between the intelligibility of speech and memory for that speech. Here, the notion was that this gap between speech intelligibility and memorability is a function of the extent to which the spoken message seizes limited immediate memory resources (e.g., Kjellberg, Ljung, & Hallman, 2008. Accordingly, the more difficult the processing of the spoken message, the less resources are available for elaboration, storage, and recall of that spoken material. However, it was not previously known how increasing that difficulty affected the memory processing of semantically rich spoken material. This investigation showed that noise impairs higher levels of cognitive analysis. A variant of the Deese-Roediger-McDermott procedure that encourages semantic elaborative processes was deployed. On each trial, participants listened to a 36-item list comprising 12 words blocked by each of 3 different themes. Each of those 12 words (e.g., bed, tired, snore… was associated with a critical lure theme word that was not presented (e.g., sleep. Word lists were either presented without noise or at a signal-to-noise ratio of 5 decibels upon an A-weighting. Noise reduced false recall of the critical words, and decreased the semantic clustering of recall. Theoretical and practical implications are discussed.

  1. 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.

  2. Failing to get the gist of what's being said: background noise impairs higher-order cognitive processing.

    Science.gov (United States)

    Marsh, John E; Ljung, Robert; Nöstl, Anatole; Threadgold, Emma; Campbell, Tom A

    2015-01-01

    A dynamic interplay is known to exist between auditory processing and human cognition. For example, prior investigations of speech-in-noise have revealed there is more to learning than just listening: Even if all words within a spoken list are correctly heard in noise, later memory for those words is typically impoverished. These investigations supported a view that there is a "gap" between the intelligibility of speech and memory for that speech. Here, the notion was that this gap between speech intelligibility and memorability is a function of the extent to which the spoken message seizes limited immediate memory resources (e.g., Kjellberg et al., 2008). Accordingly, the more difficult the processing of the spoken message, the less resources are available for elaboration, storage, and recall of that spoken material. However, it was not previously known how increasing that difficulty affected the memory processing of semantically rich spoken material. This investigation showed that noise impairs higher levels of cognitive analysis. A variant of the Deese-Roediger-McDermott procedure that encourages semantic elaborative processes was deployed. On each trial, participants listened to a 36-item list comprising 12 words blocked by each of 3 different themes. Each of those 12 words (e.g., bed, tired, snore…) was associated with a "critical" lure theme word that was not presented (e.g., sleep). Word lists were either presented without noise or at a signal-to-noise ratio of 5 decibels upon an A-weighting. Noise reduced false recall of the critical words, and decreased the semantic clustering of recall. Theoretical and practical implications are discussed.

  3. The protective effect of moderate noisy backgrounds for certain period on hearing after exposure to a traumatic noise in guinea pig

    Directory of Open Access Journals (Sweden)

    Xiao-hua WANG

    2013-03-01

    Full Text Available Objective  To investigate the protective effect of moderate noisy backgrounds on guinea pig's hearing after an exposure to a traumatic noise. Methods  Thirty guinea pigs were randomly divided into five groups (6 each. Animals in group A, B, C and D were subjected to noise of 84 decibels sound pressure level (dB SPL for 4, 8, 24 and 0 hour respectively after a traumatic exposure of 110 dB SPL, and those in group E were kept in quiet environment. Distortion product oto-acoustic emission (DPOAE amplitudes were determined on 1 day prior, and 1 and 7 days after noise exposure. Blood plasma was obtained to determine the contents of malondialdehyde (MDA and the activities of hemocuprein (SOD and nitricoxide synthase (NOS at the end of the experiment. Results  Noise-induced hearing loss was caused in group D after a traumatic exposure. At the 1st and 7th day after exposure, DPOAE amplitudes were higher in group A and B than in group D, especially at high frequencies, while no significant difference was observed between group C and D. At the 7th day after exposure, the activity of SOD lowered, while the content of MDA increased in group A and B as compared with group E (P<0.05. The content of MDA in group A increased as compared with group D (P<0.05. Conclusion  After the traumatic noise-exposure, the recovery of noise-induced hearing loss, especially the high-frequency hearing loss could be motivated when exposed to noise at 84 dB SPL for 4 or 8 hours.

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

    International Nuclear Information System (INIS)

    Ozveaminian, K.

    1969-01-01

    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) [fr

  5. The Galker test of speech reception in noise; associations with background variables, middle ear status, hearing, and language in Danish preschool children.

    Science.gov (United States)

    Lauritsen, Maj-Britt Glenn; Söderström, Margareta; Kreiner, Svend; Dørup, Jens; Lous, Jørgen

    2016-01-01

    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. 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 and daycare teachers completed questionnaires on the children's ability to hear and understand speech. As most of the variables were not assessed using interval scales, non-parametric statistics (Goodman-Kruskal's gamma) were used for analyzing associations with the Galker test score. For comparisons, analysis of variance (ANOVA) was used. Interrelations were adjusted for using a non-parametric graphic model. In unadjusted analyses, the Galker test was associated with gender, age group, language development (Reynell revised scale), audiometry, and tympanometry. The Galker score was also associated with the parents' and day care teachers' reports on the children's vocabulary, sentence construction, and pronunciation. Type B tympanograms were associated with a mean hearing 5-6dB below that of than type A, C1, or C2. In the graphic analysis, Galker scores were closely and significantly related 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). The Galker test of speech reception in noise appears promising as an easy and quick tool for evaluating preschool children's understanding of spoken words in noise, and it correlated well with the day care teachers' reports and less with the parents' reports. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  6. Effects of age and background noise on processing a mistuned harmonic in an otherwise periodic complex sound.

    Science.gov (United States)

    Alain, Claude; McDonald, Kelly; Van Roon, Patricia

    2012-01-01

    Older adults presented with short (i.e., 40 ms) harmonic complex tones show a reduced likelihood of hearing the mistuned harmonic as a separate sound. Here, we examined whether this age difference for the mistuned harmonic would generalize to a longer signal duration (i.e., 200 ms). We measured auditory evoked fields (AEFs) using magnetoencephalography while young and older adults were presented with harmonic complex tones that either had all partials of the tones in tune (single sound object) or contained a 4 or 16% mistuned harmonic (dual sound objects). The auditory stimuli were presented in isolation or embedded in low or moderate levels of continuous white noise. For each participant, we modeled the AEFs with a pair of dipoles in the superior temporal plane and examined the effects of age and noise on the amplitude and latency of the resulting source waveforms. The present study reveals similar noise-induced increases in N1m and object-related negativity in young and older adults which may be mediated via efferent feedback connections and/or changes in the temporal window of integration. We observed less age-related differences in concurrent sound segregation for stimuli that matched the duration of the temporal integration window of auditory perception (i.e., ∼200 ms) than for short duration sounds (i.e., 40 ms). Possible explanations for this duration-dependent age-related decline in concurrent sound perception are a general slowing in auditory processing and/or lengthening of the temporal integration window. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. The impact of compression of speech signal, background noise and acoustic disturbances on the effectiveness of speaker identification

    Science.gov (United States)

    Kamiński, K.; Dobrowolski, A. P.

    2017-04-01

    The paper presents the architecture and the results of optimization of selected elements of the Automatic Speaker Recognition (ASR) system that uses Gaussian Mixture Models (GMM) in the classification process. Optimization was performed on the process of selection of individual characteristics using the genetic algorithm and the parameters of Gaussian distributions used to describe individual voices. The system that was developed was tested in order to evaluate the impact of different compression methods used, among others, in landline, mobile, and VoIP telephony systems, on effectiveness of the speaker identification. Also, the results were presented of effectiveness of speaker identification at specific levels of noise with the speech signal and occurrence of other disturbances that could appear during phone calls, which made it possible to specify the spectrum of applications of the presented ASR system.

  8. Application of the pulse-rise-time discriminator for background noise decreasing in proportional x-ray counters

    International Nuclear Information System (INIS)

    Goganov, D.A.; Guslina, A.G.; Korolev, V.F.; Lozinskij, B.S.; Sklyankin, V.A.

    1977-01-01

    The intrinsic background of commercial rising edge discriminator - based proportional counters has been measured. The block-diagram of the experimental apparatus comprises the detector to be tested, a charge-sensitive amplifier with an amplitude analyzer, a rising edge discriminator (RED) and a scaling device. The rising edges have been analyzed in the range between 0.2 to 0.7 of the pulse amplitude. The RED threshold has been preset to cut off all the edges longer than those of 55 Fe (to register 87% of the 55 Fe quanta). It has been found that by limiting the amplitude discriminator window to +-20% and using a RED the background of commercial counters can be reduced by about an order

  9. Frequency filtering to suppress background noise in fingerprint evidence: quantifying the fidelity of digitally enhanced fingerprint images.

    Science.gov (United States)

    Speir, Jacqueline A; Hietpas, Jack

    2014-09-01

    Fingerprint evidence can benefit in image quality if transformed using digital image processing techniques. This is especially true when considering prints that cannot be easily lifted (such as those deposited on porous paper substrates), or when the mechanism of lifting does not effectively reduce background interferences. In these instances, frequency filtering is one type of mathematical transformation that can serve to increase image clarity and the ability to extract minutiae relevant to pairwise comparisons. To quantify the impact of frequency filtering on image quality, high quality and low quality (noisy) prints were collected. The high quality prints served as exemplars that were compared to the low quality prints both pre- and post-filtering. The resulting pairwise match scores indicate that: (1) frequency filtering has a low probability of creating false positive associations, (2) 90% of the post-filtered images result in a normalized gain in match score, (3) frequency filtering doubled the probability of obtaining match scores greater than 30% (for the automated algorithm employed in this study), and (4) filtering can double the probability of obtaining 10 or more matching minutiae when comparing same source prints. Overall, the research indicates a reasonable and quantifiable payoff in increased clarity, matching minutiae and pairwise similarity for post-filtered images when compared to known-match exemplars. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  10. Protection by low-dose kanamycin against noise-induced hearing loss in mice: dependence on dosing regimen and genetic background.

    Science.gov (United States)

    Ohlemiller, Kevin K; Rybak Rice, Mary E; Rosen, Allyson D; Montgomery, Scott C; Gagnon, Patricia M

    2011-10-01

    We recently demonstrated that sub-chronic low-dose kanamycin (KM, 300 mg/kg sc, 2×/day, 10 days) dramatically reduces permanent noise-induced hearing loss (NIHL) and hair cell loss in 1 month old CBA/J mice (Fernandez et al., 2010, J. Assoc. Res. Otolaryngol. 11, 235-244). Protection by KM remained for at least 48 h after the last dose, and appeared to involve a cumulative effect of multiple doses as part of a preconditioning process. The first month of life lies within the early 'sensitive period' for both cochlear noise and ototoxic injury in mice, and CBA/J mice appear exquisitely vulnerable to noise during this period (Ohlemiller et al., 2011; Hearing Res. 272, 13-20). From our initial data, we could not rule out 1) that less rigorous treatment protocols than the intensive one we applied may be equally-or more-protective; 2) that protection by KM is tightly linked to processes unique to the sensitive period for noise or ototoxins; or 3) that protection by KM is exclusive to CBA/J mice. The present experiments address these questions by varying the number and timing of fixed doses (300 mg/kg sc) of KM, as well as the age at treatment in CBA/J mice. We also tested for protection in young C57BL/6J (B6) mice. We find that nearly complete protection against at least 2 h of intense (110 dB SPL) broadband noise can be observed in CBA/J mice at least for ages up to 1 year. Reducing dosing frequency to as little as once every other day (a four-fold decrease in dosing frequency) appeared as protective as twice per day. However, reducing the number of doses to just 1 or 2, followed by noise 24 or 48 h later greatly reduced protection. Notably, hearing thresholds and hair cells in young B6 mice appeared completely unprotected by the same regimen that dramatically protects CBA/J mice. We conclude that protective effects of KM against NIHL in CBA/J mice can be engaged by a wide range of dosing regimens, and are not exclusive to the sensitive period for noise or ototoxins

  11. Vocal Noise Cancellation From Respiratory Sounds

    National Research Council Canada - National Science Library

    Moussavi, Zahra

    2001-01-01

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

  12. Morphology of the spectral resonance structure of the electromagnetic background noise in the range of 0.1–4 Hz at L = 5.2

    Directory of Open Access Journals (Sweden)

    A. G. Yahnin

    2003-03-01

    Full Text Available Continuous observations of fluctuations of the geomagnetic field at Sodankylä Geophysical Observatory (L = 5.2 were used for a comprehensive morphological study of the spectral resonance structure (SRS seen in the background electromagnetic noise in the frequency range of 0.1–4.0 Hz. It is shown that the occurrence rate of SRS is higher in the nighttime than in the daytime. The occurrence rate is higher in winter than in summer. The SRS frequencies and the difference between neighbouring eigenfrequencies (the frequency scale increase towards nighttime and decrease towards daytime. Both frequency scale and occurrence rate exhibit a clear tendency to decrease from minimum to maximum of the solar activity cycle. It is found that the occurrence rate of SRS decreases when geomagnetic activity increases. The SRS is believed to be a consequence of a resonator for Alfvén waves, which is suggested to exist in the upper ionosphere. According to the theory of the ionospheric Alfvén resonator (IAR, characteristics of SRS crucially depend on electron density in the F-layer maximum, as well as on the altitudinal scale of the density decay above the maximum.We compared the SRS morphological properties with predictions of the IAR theory. The ionospheric parameters needed for calculation were obtained from the ionosphere model (IRI-95, as well as from measurements made with the ionosonde in Sodankylä. We conclude that, indeed, the main morphological properties of SRS are explained on the basis of the IAR theory. The measured parameters of SRS can be used for improving the ionospheric models.Key words. Ionosphere (auroral ionosphere; wave propagation – Radio Science (electromagnetic noise and interference

  13. Response to Comment: RE: Ohlenforst et al. (2016) Exploring the Relationship Between Working Memory, Compressor Speed, and Background Noise Characteristics, Ear Hear 37, 137–143

    DEFF Research Database (Denmark)

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

    2017-01-01

    We appreciate the opportunity to respond to the comment on our study (Ohlenforst et al. 2016). The issue of concern to the letter writer, “The speech and the noise signals were separately compressed before the SNRs [signal-to-noise ratios] were computed based on the signal’s root mean square values.......” referred to a calibration process in which the compressor gain function, derived from the mixed signal, was applied separately to the speech signal and to the separate noise signals to quantify the output signal to noise ratio. This was done to investigate compressor functionality. However, to create...... the test stimuli presented to the participants, the compressor was applied to the mixed speech-plus-noise signal at a specified input signal to noise ratio (−4, −2, and 0 dB), not on the speech signal or the noise signals alone. That is, the actual stimulus processing was all done on the mixed speech-plus-noise...

  14. Dispersive changes in magnetic background noise polarization at 0.1 to 6Hz during sunset and sunrise at L=1.3

    Directory of Open Access Journals (Sweden)

    T. Bösinger

    2004-06-01

    Full Text Available Polarization properties of the magnetic background noise (MBN and the spectral resonance structure (SRS of the ionospheric Alfvén resonator (IAR below the first Schumann resonance but above 0.1 Hz are measured by a sensitive pulsation magnetometer at the island of Crete (L=1.3 and analyzed using the existing SRS theory by Belyaev et al. (1989b. The focus of the paper is on the systematic changes in the MBN and SRS properties associated with the transition from a sunlit to a dark ionosphere (sunset and vice versa (sunrise. We are able to pinpoint in observations an E-region and F-region terminator effect and to simulate it by means of a simple ionosphere model, implying the formalism given by Belyaev et al. (1989b. The E-region terminator effect is associated with an apparent control for the SRS presence or absence with no clear frequency dispersion in polarization properties, whereas the F-region terminator effect exhibits strong frequency dispersion, especially in the low frequency range. This yields a change in the ellipticity of MBN, starting as early as 2 to 3h ahead of the "zero-line" of the terminator. In a 24h presentation of the ellipticity versus frequency and time, the sunrise/sunset effect produces a sharp, dispersive boundary between night and day (day and night. Only inside this boundary, during the night hours, is SRS observed, at times accompanied by a large quasi-periodic long period modulation in the azimuthal angle of the major axis of the polarization ellipse. Attention is also paid to peculiarities in the low frequency range (~0.1Hz, where especially large changes in the polarization properties occur in association with the passage of the terminator. The F-region effect is very distinct and well reproduced by our simple model. Changes in the azimuth associated with the E-region terminator effect are of the order of 20°.

  15. Dispersive changes in magnetic background noise polarization at 0.1 to 6Hz during sunset and sunrise at L=1.3

    Directory of Open Access Journals (Sweden)

    T. Bösinger

    2004-06-01

    Full Text Available Polarization properties of the magnetic background noise (MBN and the spectral resonance structure (SRS of the ionospheric Alfvén resonator (IAR below the first Schumann resonance but above 0.1 Hz are measured by a sensitive pulsation magnetometer at the island of Crete (L=1.3 and analyzed using the existing SRS theory by Belyaev et al. (1989b. The focus of the paper is on the systematic changes in the MBN and SRS properties associated with the transition from a sunlit to a dark ionosphere (sunset and vice versa (sunrise. We are able to pinpoint in observations an E-region and F-region terminator effect and to simulate it by means of a simple ionosphere model, implying the formalism given by Belyaev et al. (1989b. The E-region terminator effect is associated with an apparent control for the SRS presence or absence with no clear frequency dispersion in polarization properties, whereas the F-region terminator effect exhibits strong frequency dispersion, especially in the low frequency range. This yields a change in the ellipticity of MBN, starting as early as 2 to 3h ahead of the "zero-line" of the terminator. In a 24h presentation of the ellipticity versus frequency and time, the sunrise/sunset effect produces a sharp, dispersive boundary between night and day (day and night. Only inside this boundary, during the night hours, is SRS observed, at times accompanied by a large quasi-periodic long period modulation in the azimuthal angle of the major axis of the polarization ellipse. Attention is also paid to peculiarities in the low frequency range (~0.1Hz, where especially large changes in the polarization properties occur in association with the passage of the terminator. The F-region effect is very distinct and well reproduced by our simple model. Changes in the azimuth associated with the E-region terminator effect are of the order of 20°.

  16. 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

    Objective: Speech production in noise with varying talker-to-listener distance has been well studied for the open ear condition. However, occluding the ear canal can affect the auditory feedback and cause deviations from the models presented for the open-ear condition. Communication is a main...... 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...... 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...

  17. Analysis of the background noise of field effect transistors in MOS complementary technology and application in the construction of a current-sensitive integrated amplifier

    International Nuclear Information System (INIS)

    Beuville, E.

    1989-10-01

    A low noise amplifier for use in high energy physics is developed. The origin and the mechanisms of the noise in MOSFET transistors is carried out with the aim of minimizing such effects in amplifiers. The research is applied in the construction of a current-sensitive integrated amplifier. The time scale continuous filtering principle is used and allows the detection of particles arriving in the counter in a random distribution. The rules which must be taken into account in the construction of an analog integrated circuit are shown [fr

  18. A retention-time-shift-tolerant background subtraction and noise reduction algorithm (BgS-NoRA) for extraction of drug metabolites in liquid chromatography/mass spectrometry data from biological matrices.

    Science.gov (United States)

    Zhu, Peijuan; Ding, Wei; Tong, Wei; Ghosal, Anima; Alton, Kevin; Chowdhury, Swapan

    2009-06-01

    A retention-time-shift-tolerant background subtraction and noise reduction algorithm (BgS-NoRA) is implemented using the statistical programming language R to remove non-drug-related ion signals from accurate mass liquid chromatography/mass spectrometry (LC/MS) data. The background-subtraction part of the algorithm is similar to a previously published procedure (Zhang H and Yang Y. J. Mass Spectrom. 2008, 43: 1181-1190). The noise reduction algorithm (NoRA) is an add-on feature to help further clean up the residual matrix ion noises after background subtraction. It functions by removing ion signals that are not consistent across many adjacent scans. The effectiveness of BgS-NoRA was examined in biological matrices by spiking blank plasma extract, bile and urine with diclofenac and ibuprofen that have been pre-metabolized by microsomal incubation. Efficient removal of background ions permitted the detection of drug-related ions in in vivo samples (plasma, bile, urine and feces) obtained from rats orally dosed with (14)C-loratadine with minimal interference. Results from these experiments demonstrate that BgS-NoRA is more effective in removing analyte-unrelated ions than background subtraction alone. NoRA is shown to be particularly effective in the early retention region for urine samples and middle retention region for bile samples, where the matrix ion signals still dominate the total ion chromatograms (TICs) after background subtraction. In most cases, the TICs after BgS-NoRA are in excellent qualitative correlation to the radiochromatograms. BgS-NoRA will be a very useful tool in metabolite detection and identification work, especially in first-in-human (FIH) studies and multiple dose toxicology studies where non-radio-labeled drugs are administered. Data from these types of studies are critical to meet the latest FDA guidance on Metabolite in Safety Testing (MIST). Copyright (c) 2009 John Wiley & Sons, Ltd.

  19. Feasibility of Epidemiologic Research on Nonauditory Health Effects of Residential Aircraft Noise Exposure. Volume 2. Background, General Process Model and Potential Studies

    Science.gov (United States)

    1989-01-27

    noises can generate significant apparent exposure. The long-term average at-ear level of a person’s own speech exceeds 75 dBA; artifacts such as...loss extends to lower frequency regions important for speech intelligibility. Presbycusis is the term used for the common pattern of high frequency...private 94 4Am~ odio * M011 m~rophone locations o Mobile von mocraphoe (~it I vistiple array) Lle!e 4D El Roma 0--Station 4 (10 miles) Minco Tuttl

  20. Noise suppression by noise

    OpenAIRE

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

    2001-01-01

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

  1. 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.

  2. TU-H-BRA-09: Relationship Between B0 and the Contrast-To-Noise Ratio (CNR) of Tumour to Background for MRI/Radiotherapy Hybrids

    Energy Technology Data Exchange (ETDEWEB)

    Wachowicz, K; DeZanche, N; Fallone, B [Cross Cancer Institute, Edmonton, Alberta (Canada); University of Alberta, Edmonton, Alberta (Canada); Yip, E [University of Alberta, Edmonton, Alberta (Canada); Volotovskyy, V [Cross Cancer Institute, Edmonton, Alberta (Canada)

    2016-06-15

    Purpose: To investigate the relationship in MRI between B{sub 0} and the contrast-to-noise ratio (CNR) of various tumour/normal tissue pairs. This study is motivated by the current interest in MRI/radiotherapy hybrids, for which multiple magnetic field strengths have been proposed. CNR is the single most important parameter governing the ability of a system to identify a tumour in real time for treatment guidance. The MRI community has long since recognized that the SNR of a well-designed MR system is roughly proportional to B{sub 0}, the polarizing magnetic field. However, the CNR between two tissues is much more complicated - dependent not only on this signal behavior, but also on the different relaxation properties of the tissues. Methods: Experimentally-based models of B{sub 0}-dependant relaxation for various tumour and normal tissues from the literature were used in conjunction with signal equations for MR sequences suitable for rapid realtime imaging to develop field-dependent predictions for CNR. These CNR models were developed for liver, lung, breast, glioma, and kidney tumours for spoiled-gradient echo (SGE) and balanced steady-state free precession (bSSFP) sequences. Results: In all cases there was an improved CNR at lower fields compared to linear dependency. Further, in some tumour sites, the CNR at lower fields was found to be comparable to, or sometimes higher than those at higher fields (i.e. bSSFP CNR for glioma, kidney and liver tumours). Conclusion: Due to the variation of tissue relaxation parameters with field, lower B{sub 0} fields have been shown to perform as well or better (in terms of CNR) than higher fields for some tumour sites. In other sites this effect was less pronounced. It is the complex relationship between CNR and B{sub 0} that leads to greater CNR at 0.5 T for certain tumour types studied here for fast imaging. B. Gino Fallone is a co-founder and CEO of MagnetTx Oncology Solutions (under discussions to license Alberta bi

  3. Optical Johnson noise thermometry

    Science.gov (United States)

    Shepard, R. L.; Blalock, T. V.; Maxey, L. C.; Roberts, M. J.; Simpson, M. L.

    1989-01-01

    A concept is being explored that an optical analog of the electrical Johnson noise may be used to measure temperature independently of emissivity. The concept is that a laser beam may be modulated on reflection from a hot surface by interaction of the laser photons with the thermally agitated conduction electrons or the lattice phonons, thereby adding noise to the reflected laser beam. If the reflectance noise can be detected and quantified in a background of other noise in the optical and signal processing systems, the reflectance noise may provide a noncontact measurement of the absolute surface temperature and may be independent of the surface's emissivity.

  4. Noise Gating Solar Images

    Science.gov (United States)

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

    2017-08-01

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

  5. Active Noise Control for Dishwasher noise

    Science.gov (United States)

    Lee, Nokhaeng; Park, Youngjin

    2016-09-01

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

  6. 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....

  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...

  8. Technical noise supplement : TeNS : a technical supplement to the Traffic Noise Analysis Protocol.

    Science.gov (United States)

    1998-10-01

    The purpose of this Technical Noise Supplement (TeNS) is to provide technical background : information on transportation-related noise in general and highway traffic noise in : particular. It is designed to elaborate on technical concepts and procedu...

  9. Noise Pollution

    Science.gov (United States)

    ... Us Share Clean Air Act 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 ...

  10. Double beta radioactivity and physics of the neutrino. Study of the background noise at 3 MeV in the search of {sup 100}Mo beta beta decay; Double radioactivite beta et physique du neutrino. Etude du bruit de fond a 3 MeV dans la recherche de la desintegration beta beta du {sup 100}Mo

    Energy Technology Data Exchange (ETDEWEB)

    Piquemal, F.

    1994-05-01

    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 10{sup 25} years for {sup 100}Mo). 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{sup +} - e{sup -} 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 {sup 214}Bi 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{sup +} - e{sup -}pairs. (author).

  11. Combustion noise

    Science.gov (United States)

    Strahle, W. C.

    1977-01-01

    A review of the subject of combustion generated noise is presented. Combustion noise is an important noise source in industrial furnaces and process heaters, turbopropulsion and gas turbine systems, flaring operations, Diesel engines, and rocket engines. The state-of-the-art in combustion noise importance, understanding, prediction and scaling is presented for these systems. The fundamentals and available theories of combustion noise are given. Controversies in the field are discussed and recommendations for future research are made.

  12. Quantum Noise

    International Nuclear Information System (INIS)

    Beenakker, C W J

    2005-01-01

    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)

  13. Background Material

    DEFF Research Database (Denmark)

    Zandersen, Marianne; Hyytiäinen, Kari; Saraiva, Sofia

    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....

  14. Background radiation

    International Nuclear Information System (INIS)

    Arnott, D.

    1985-01-01

    The effects of background radiation, whether natural or caused by man's activities, are discussed. The known biological effects of radiation in causing cancers or genetic mutations are explained. The statement that there is a threshold below which there is no risk is examined critically. (U.K.)

  15. Evaluation of noise pollution in oil extracting region of Lavan and the effect of noise enclosure on noise abatement

    Directory of Open Access Journals (Sweden)

    F. Golbabaei

    2007-09-01

    Full Text Available Background and aims   Overexposure to industrial noise pollution induce hearing loss workers. Occupational hearing loss may cause interference whit oral communication, so it may  increase the risk of occupational accidents in workplace as well as affects whit social activities.  This study was conducted on Lavan Island, are of oil extracting regions in the south of Iran. The  object of this study was to evaluate noise pollution and determining the effect of noise enclosure  on noise abatement.   Methods   The noise sources were recognized and noise pressure level was measured by CEL- 440. Noise dose of the exposed workers in high level noise area were measured by CEL 272.   Results   Major noise sources were gas turbines, diesel generators, compressors, fans and gas containing pips, noise contour map revealers that noise level were higher than the recommended national exposure limit. The results of workers noise dose show that their noise exposure were  higher than the recommended value, (p<0.001. Finally, by using the results of noise frequency  analysis of different noise sources, the noise pressure level of each sources was determined in   terms of enclosing them.   Conclusion   By enclosing the noise sources, noise pressure levels can be lowered douse to  acceptable levels but limitation of applying enclosure should be regarded.  

  16. 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.)

  17. Noise Protection

    Science.gov (United States)

    1980-01-01

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

  18. Environmental Noise

    Science.gov (United States)

    Rumberg, Martin

    Environmental noise may be defined as unwanted sound that is caused by emissions from traffic (roads, air traffic corridors, and railways), industrial sites and recreational infrastructures, which may cause both annoyance and damage to health. Noise in the environment or community seriously affects people, interfering with daily activities at school, work and home and during leisure time.

  19. Drone noise

    Science.gov (United States)

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

    2017-11-01

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

  20. Noise Pollution and Health Effects

    Directory of Open Access Journals (Sweden)

    Geravandi

    2015-01-01

    Full Text Available Background Noise pollution is of particular importance due to the physical and psychological effects on humans. Noise is a stressor that affects the autonomic nervous system and the endocrine system. Noise is also a threat to marine and terrestrial ecosystems. Health risks from noise are correlated with road traffic. In other words, noise health effects are the health consequences of elevated sound levels. Objectives This study aims to determine the effect of noise pollution (near roadways on health issues in Ahvaz, Iran. Materials and Methods In this cross-sectional study, equivalent sound pressure level were measured by sound level meters TES-1353 in 75 locations around 4 roadways, which had a high load of traffic in Ahvaz City during day time. During the study, 820 measurements were recorded at measuring stations, for 7 days per week with 1-hour interval between each measurement. Statistical analysis was carried out by SPSS software. Results According to the research findings, the equivalent sound pressure levels in all stations were 76.28 ± 3.12 dB (Mean ± SD. According to sound measurements and the survey questionnaire, noise pollution is higher than EPA (US Environmental Protection Agency and Iran standard level. Based on result of this study the worst noise health effects were the nervousness and sleep quality during 2012. Conclusions According to the results of this study, with increasing load of traffic, there is an increasing need for proper consideration plans to control noise pollution and prevent its effects.

  1. Observing a Gravitational Wave Background With Lisa

    National Research Council Canada - National Science Library

    Tinto, M; Armstrong, J; Estabrook, F

    2000-01-01

    .... Comparison of the conventional Michelson interferometer observable with the fully-symmetric Sagnac data-type allows unambiguous discrimination between a gravitational wave background and instrumental noise. The method presented here can be used to detect a confusion-limited gravitational wave background.

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

    Science.gov (United States)

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

    2017-10-01

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

  3. Anthropogenic noise changes arthropod abundances.

    Science.gov (United States)

    Bunkley, Jessie P; McClure, Christopher J W; Kawahara, Akito Y; Francis, Clinton D; Barber, Jesse R

    2017-05-01

    Anthropogenic noise is a widespread and growing form of sensory pollution associated with the expansion of human infrastructure. One specific source of constant and intense noise is that produced by compressors used for the extraction and transportation of natural gas. Terrestrial arthropods play a central role in many ecosystems, and given that numerous species rely upon airborne sounds and substrate-borne vibrations in their life histories, we predicted that increased background sound levels or the presence of compressor noise would influence their distributions. In the second largest natural gas field in the United States (San Juan Basin, New Mexico, USA), we assessed differences in the abundances of terrestrial arthropod families and community structure as a function of compressor noise and background sound level. Using pitfall traps, we simultaneously sampled five sites adjacent to well pads that possessed operating compressors, and five alternate, quieter well pad sites that lacked compressors, but were otherwise similar. We found a negative association between sites with compressor noise or higher levels of background sound and the abundance of five arthropod families and one genus, a positive relationship between loud sites and the abundance of one family, and no relationship between noise level or compressor presence and abundance for six families and two genera. Despite these changes, we found no evidence of community turnover as a function of background sound level or site type (compressor and noncompressor). Our results indicate that anthropogenic noise differentially affects the abundances of some arthropod families. These preliminary findings point to a need to determine the direct and indirect mechanisms driving these observed responses. Given the diverse and important ecological functions provided by arthropods, changes in abundances could have ecological implications. Therefore, we recommend the consideration of arthropods in the environmental

  4. Noise immission from wind turbines

    International Nuclear Information System (INIS)

    1999-01-01

    The project has dealt with practical ways to reduce the influence of background noise caused by wind acting on the measuring microphones. The uncertainty of measured noise emission (source strength) has been investigated. The main activity was a Round Robin Test involving measurements by five laboratories at the same wind turbine. Each laboratory brought its own instrumentation and performed the measurements and analyses according to their interpretation. The tonality of wind turbine noise is an essential component of the noise impact on the environment. In the present project the uncertainty in the newest existing methods for assessing tonality was investigated. The project included noise propagation measurements in different weather conditions around wind turbines situated in different types of terrain. The results were used to validate a noise propagation model developed in the project. Finally, the project also included a study with listeners evaluating recordings of wind turbine noise. The results are intended as guidance for wind turbine manufacturers in identifying the aspects of wind turbine noise most important to annoyance. (author)

  5. Occupational Noise Exposure

    Science.gov (United States)

    ... Safety and Health Topics / Occupational Noise Exposure Occupational Noise Exposure This page requires that javascript be enabled ... interprets the signal as sound. x What is noise? Noise and vibration are both fluctuations in the ...

  6. 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....

  7. Yesterday's noise - today's signal

    International Nuclear Information System (INIS)

    Serdula, K.J.

    1978-01-01

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

  8. Fractal and topological sustainable methods of overcoming expected uncertainty in the radiolocation of low-contrast targets and in the processing of weak multi-dimensional signals on the background of high-intensity noise: A new direction in the statistical decision theory

    Science.gov (United States)

    Potapov, A. A.

    2017-11-01

    The main purpose of this work is to interpret the main directions of radio physics, radio engineering and radio location in “fractal” language that makes new ways and generalizations on future promising radio systems. We introduce a new kind and approach of up-to-date radiolocation: fractal-scaling or scale-invariant radiolocation. The new topologic signs and methods of detecting the low-contrast objects against the high-intensity noise background are presented. It leads to basic changes in the theoretical radiolocation structure itself and also in its mathematical apparatus. The fractal radio systems conception, sampling topology, global fractal-scaling approach and the fractal paradigm underlie the scientific direction established by the author in Russia and all over the world for the first time ever.

  9. 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.

  10. Noise Abatement

    Science.gov (United States)

    1983-01-01

    SMART, Sound Modification and Regulated Temperature compound, is a liquid plastic mixture with exceptional energy and sound absorbing qualities. It is derived from a very elastic plastic which was an effective noise abatement material in the Apollo Guidance System. Discovered by a NASA employee, it is marketed by Environmental Health Systems, Inc. (EHS). The product has been successfully employed by a diaper company with noisy dryers and a sugar company with noisy blowers. The company also manufactures an audiometric test booth and acoustical office partitions.

  11. Amperometric noise at thin film band electrodes.

    Science.gov (United States)

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

    2012-09-18

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

  12. Annoyance rating of wind turbine noise

    International Nuclear Information System (INIS)

    Iredale, R.A.

    1992-01-01

    This paper proposes a simple criterion for noise limitation of wind turbines: 'The La A50 from a Wind Farm should not exceeding the L A50 of the wind generated background plus 5dB at any place of potential complaint'. This criterion is then examined and developed in the light of experience to date with turbine noise complaint and procedures. (author)

  13. Urban Rail Noise Abatement Program : A Description

    Science.gov (United States)

    1980-03-01

    This report presents the background, current activities, and future plans for the Urban Rail Noise Abatement Program. This program, sponsored by the Office of Technology Development and Deployment of the Urban Mass Transportation Administration (UMTA...

  14. Partial and Total Annoyance Due to Road Traffic Noise Combined with Aircraft or Railway Noise: Structural Equation Analysis

    Science.gov (United States)

    Gille, Laure-Anne; Marquis-Favre, Catherine; Lam, Kin-Che

    2017-01-01

    Structural equation modeling was used to analyze partial and total in situ annoyance in combined transportation noise situations. A psychophysical total annoyance model and a perceptual total annoyance model were proposed. Results show a high contribution of Noise exposure and Noise sensitivity to Noise annoyance, as well as a causal relationship between noise annoyance and lower Dwelling satisfaction. Moreover, the Visibility of noise source may increase noise annoyance, even when the visible noise source is different from the annoying source under study. With regards to total annoyance due to road traffic noise combined with railway or aircraft noise, even though in both situations road traffic noise may be considered background noise and the other noise source event noise, the contribution of road traffic noise to the models is greater than railway noise and smaller than aircraft noise. This finding may be explained by the difference in sound pressure levels between these two types of combined exposures or by the aircraft noise level, which may also indicate the city in which the respondents live. Finally, the results highlight the importance of sample size and variable distribution in the database, as different results can be observed depending on the sample or variables considered. PMID:29189751

  15. Noise thermometer

    International Nuclear Information System (INIS)

    Von Brixy, H.; Kakuta, Tsunemi.

    1996-03-01

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

  16. Noise thermometer

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-03-01

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

  17. 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?

  18. System for the suppression of noise and of noise fluctuations: extraction of a net signal from another one containing frequencies of noise and discontinuous signal

    International Nuclear Information System (INIS)

    Rambaut, M.

    1989-01-01

    A patent is claimed for an invention relating to a system for the suppression of noise and noise fluctuations. The aim of the system is the detection of the signal contained in noise-and-discontinuous signal mixed frequencies. The invention is to be applied in radiation detection. The results of the measurements are reliable for short counting rates, as compared with the time constant of the background noise fluctuations, and for measurements performed in regions having the same background noise average. The diagram, the characteristics and the operation of the invention are described [fr

  19. Distinguishing pathogenic mutations from background genetic noise in cardiology

    DEFF Research Database (Denmark)

    Ghouse, J; Skov, M W; Bigseth, R S

    2018-01-01

    patients evaluate medical decisions in light of uncertainty regarding the consequence of the findings. Through publication of large publicly available exome/genome databases, researchers and physicians are now able to highlight dubious variants previously associated with different cardiac traits. Also......, continuous efforts through data sharing, international collaborative efforts to develop disease-gene-specific guidelines, and computational analyses using large data, will indubitably assist in better variant interpretation and classification. This article discusses the current, and quickly changing, state...

  20. Simulation of realistic background noise using multiple loudspeakers

    DEFF Research Database (Denmark)

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

    2015-01-01

    optimizes the reproduced sound at a sweet spot in the center of the array with radius determined by a spherical microphone array, which is used to derive the spherical harmonics decomposition of the reference sound. The four-loudspeaker-based method equalizes the magnitude response at the ears of a head...... positions were defined, i.e. the ears of the HATS, positions close to a device under test, and standardized positions as described in ETSI TS 103 224. A listening experiment was performed to evaluate the perceived quality of the reproduced sounds at the microphones close to a device under test...

  1. Noise and Hearing Protection

    Science.gov (United States)

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

  2. 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.

  3. 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....

  4. Assessment of Noise Pollution From Sawmill Activities in Ilorin, Nigeria

    African Journals Online (AJOL)

    This study examined noise pollution from sawmilling in Ilorin metropolis, Nigeria. Noise measurements were made using HD600 digital data logging sound level meter in conjunction with structured questionnaire which was designed to elicit noise related information. The results of the study showed that the background ...

  5. Occupational noise-induced hearing loss among workers at Jomo ...

    African Journals Online (AJOL)

    Background: Occupational noise induced hearing loss (NIHL) occurs among workers exposed to excessive amounts of noise for long durations. The average level of noise in some locations at Jomo Kenyatta International Airport (JKIA) was above the safe limit of 85dB hence workers were thought to be at risk. Objective: To ...

  6. Incorporating signal-dependent noise for hyperspectral target detection

    Science.gov (United States)

    Morman, Christopher J.; Meola, Joseph

    2015-05-01

    The majority of hyperspectral target detection algorithms are developed from statistical data models employing stationary background statistics or white Gaussian noise models. Stationary background models are inaccurate as a result of two separate physical processes. First, varying background classes often exist in the imagery that possess different clutter statistics. Many algorithms can account for this variability through the use of subspaces or clustering techniques. The second physical process, which is often ignored, is a signal-dependent sensor noise term. For photon counting sensors that are often used in hyperspectral imaging systems, sensor noise increases as the measured signal level increases as a result of Poisson random processes. This work investigates the impact of this sensor noise on target detection performance. A linear noise model is developed describing sensor noise variance as a linear function of signal level. The linear noise model is then incorporated for detection of targets using data collected at Wright Patterson Air Force Base.

  7. 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.

  8. 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)…

  9. Non-Markovian noise

    International Nuclear Information System (INIS)

    Fulinski, A.

    1994-01-01

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

  10. 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.)

  11. assessment of noise pollutio noise pollutio noise pollution

    African Journals Online (AJOL)

    eobe

    1DEPARTMENT OF WATER RESOURCES ... challenges. Symptoms of short or long periods exposure to noise include auditory effects such auditory fatigue and hearing loss, and indirect n auditory effects such as speech interfere .... ASSESSMENT OF NOISE POLLUTION FROM SAWMILL ACTIVITIES IN ILORIN, NIGERIA.

  12. assessment of noise pollutio noise pollutio noise pollution

    African Journals Online (AJOL)

    eobe

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

  13. Background sources at PEP

    International Nuclear Information System (INIS)

    Lynch, H.; Schwitters, R.F.; Toner, W.T.

    1988-01-01

    Important sources of background for PEP experiments are studied. Background particles originate from high-energy electrons and positrons which have been lost from stable orbits, γ-rays emitted by the primary beams through bremsstrahlung in the residual gas, and synchrotron radiation x-rays. The effect of these processes on the beam lifetime are calculated and estimates of background rates at the interaction region are given. Recommendations for the PEP design, aimed at minimizing background are presented. 7 figs., 4 tabs

  14. The recommendations of the noise working group

    International Nuclear Information System (INIS)

    Legerton, M.L.

    1997-01-01

    In 1993 the DTI set up a Working Group to define a framework which can be used to measure and rate the noise from wind turbines. The final report of the Noise Working Group is now available for publication. The advice on the setting of noise limits for wind farms is largely unaltered from the preliminary recommendations presented at the 17th BWEA Annual Conference [1]. This paper recaps on those recommendations and provides additional information on the measurement procedures to be used with the recommendations on noise limits. The paper describes the measurement of the existing background noise climate on which the limits are based and the procedure to be used for the measurement of turbine noise levels in the investigation of complaints. The noise limits are rated noise levels in that they can include a penalty for tones present in the noise. The level of penalty depends upon the audibility of the tone and measurement procedure for determining audibility and the associated penalty system are also described. (author)

  15. Noise suppression via generalized-Markovian processes

    Science.gov (United States)

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

    2017-11-01

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

  16. 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.

  17. Aviation noise effects

    Science.gov (United States)

    Newman, J. S.; Beattie, K. R.

    1985-03-01

    This report summarizes the effects of aviation noise in many areas, ranging from human annoyance to impact on real estate values. It also synthesizes the findings of literature on several topics. Included in the literature were many original studies carried out under FAA and other Federal funding over the past two decades. Efforts have been made to present the critical findings and conclusions of pertinent research, providing, when possible, a bottom line conclusion, criterion or perspective. Issues related to aviation noise are highlighted, and current policy is presented. Specific topic addressed include: annoyance; Hearing and hearing loss; noise metrics; human response to noise; speech interference; sleep interference; non-auditory health effects of noise; effects of noise on wild and domesticated animals; low frequency acoustical energy; impulsive noise; time of day weightings; noise contours; land use compatibility; and real estate values. This document is designed for a variety of users, from the individual completely unfamiliar with aviation noise to experts in the field.

  18. 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.

  19. 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

  20. Method for measuring self-noise of vector hydrophones

    Science.gov (United States)

    Li, Zhi; Chen, Hongjuan

    2017-09-01

    The Vector Hydrophone (VH) is widely used to remotely detect underwater targets. Accurately measuring the self-noise of the VH provides an important basis for evaluating the performance of the detection system in which it is utilized, since the ability to acquire weak signals is determined by the VH self-noise level. To accurately measure the VH self-noise level in actual working conditions, the Dual-channel Transfer Function Method (DTFM) is proposed to reduce ambient background noise interference. In this paper, the underlying principles of DTFM in reducing ambient background noise is analyzed. The numerical simulations to determine the influence of ambient background noise, and the sensitivity difference of the two VHs on the measurement results are studied. The results of measuring the VH self-noise level in a small laboratory water tank by using DTMF indicate that ambient background noise interference can be reduced effectively by employing DTMF, more accurate self-noise level can be obtained as well. The DTMF provides an effective method for accurately measuring the self-noise level of VHs and also provides technical support for the practical application of the VH in underwater acoustics.

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

    Science.gov (United States)

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

    2017-10-12

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

  2. Low Noise Infrasonic Sensor System with High Reduction of Natural Background Noise

    National Research Council Canada - National Science Library

    Kern, F; Africk, S; Cataldi, P; Chaves, R

    2006-01-01

    ...) coaxial cables, theoretically of arbitrary length, specially terminated and connected to state of the art, ultra high input impedance quiet amplifiers, tailored to the unique characteristics of the sensor outputs...

  3. 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...

  4. Helicopter Noise And Noise Abatement Procedures

    Directory of Open Access Journals (Sweden)

    Borivoj Galović

    2004-03-01

    Full Text Available The helicopter generated noise at and around the airports islower than the noise generated by aeroplanes, since their numberof operations, i. e. the number of takeoffs and landings ismuch lower than the takeoffs and landings of the aeroplanes.Out of some hundred operations a day, helicopters participatewith approximately 15%, but the very impact of noise is by nomeans negligible, since the number of helicopter flights aboveurban areas is constantly increasing.This paper attempts to analyse this phenomenon and thetype of helicopter generated noise, its negative impacts, to explainthe flight procedures and the operative procedures duringtakeoff, landing and overflight of helicopters in operations inthe vicinity and outside airports, as well as the methods of measuringand determining the limit of noise [eve~ and the resultingproblems.

  5. Noise Radar Technology Basics

    National Research Council Canada - National Science Library

    Thayaparan, T; Wernik, C

    2006-01-01

    .... In this report, the basic theory of noise radar design is treated. The theory supports the use of noise waveforms for radar detection and imaging in such applications as covert military surveillance and reconnaissance...

  6. NASA Jet Noise Research

    Science.gov (United States)

    Henderson, Brenda

    2016-01-01

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

  7. Compensatable muon collider calorimeter with manageable backgrounds

    Science.gov (United States)

    Raja, Rajendran

    2015-02-17

    A method and system for reducing background noise in a particle collider, comprises identifying an interaction point among a plurality of particles within a particle collider associated with a detector element, defining a trigger start time for each of the pixels as the time taken for light to travel from the interaction point to the pixel and a trigger stop time as a selected time after the trigger start time, and collecting only detections that occur between the start trigger time and the stop trigger time in order to thereafter compensate the result from the particle collider to reduce unwanted background detection.

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

    Directory of Open Access Journals (Sweden)

    Rainer Guski

    2017-12-01

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

  9. Noise Reduction Techniques

    Science.gov (United States)

    Hallas, Tony

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

  10. Equation for Combustion Noise

    Science.gov (United States)

    Liu, T. M.

    1982-01-01

    Mathematical relationship derived for interactions between turbulent flame and combustion noise. Relationship is rigorous theoretical correlation of combustion noise and combustion process. Establishes foundation for acoustic measurements as tool for investigating structure of turbulent flames. Mathematical relationship is expected to aid researchers in field of noise generated by combustion.

  11. Introductory guide to noise

    CSIR Research Space (South Africa)

    Ferreira, T.M

    1973-01-01

    Full Text Available The difference between sound and noise varies from one human being to another. Noise, then, is simply unwanted sound and to understand how it can be combatted we must know more about its nature. A guide of acceptable levels of noise are investigated....

  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. Background music: effects on attention performance.

    Science.gov (United States)

    Shih, Yi-Nuo; Huang, Rong-Hwa; Chiang, Hsin-Yu

    2012-01-01

    Previous studies indicate that noise may affect worker attention. However, some background music in the work environment can increase worker satisfaction and productivity. This study compared how music with, and without, lyrics affects human attention. One hundred and two participants, aged 20-24 years, were recruited into this study. Fifty-six males and 46 females participated in this study. Background music with, and without lyrics, was tested for effects on listener concentration in attention testing using a randomized controlled trial (RCT) study. The comparison results revealed that background music with lyrics had significant negative effects on concentration and attention. The findings suggest that, if background music is played in the work environment, music without lyrics is preferable because songs with lyrics are likely to reduce worker attention and performance.

  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. Active noise control in a duct to cancel broadband noise

    Science.gov (United States)

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

    2017-09-01

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

  16. Classical noise, quantum noise and secure communication

    International Nuclear Information System (INIS)

    Tannous, C; Langlois, J

    2016-01-01

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

  17. 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....

  18. Noise-invariant Neurons in the Avian Auditory Cortex: Hearing the Song in Noise

    Science.gov (United States)

    Moore, R. Channing; Lee, Tyler; Theunissen, Frédéric E.

    2013-01-01

    Given the extraordinary ability of humans and animals to recognize communication signals over a background of noise, describing noise invariant neural responses is critical not only to pinpoint the brain regions that are mediating our robust perceptions but also to understand the neural computations that are performing these tasks and the underlying circuitry. Although invariant neural responses, such as rotation-invariant face cells, are well described in the visual system, high-level auditory neurons that can represent the same behaviorally relevant signal in a range of listening conditions have yet to be discovered. Here we found neurons in a secondary area of the avian auditory cortex that exhibit noise-invariant responses in the sense that they responded with similar spike patterns to song stimuli presented in silence and over a background of naturalistic noise. By characterizing the neurons' tuning in terms of their responses to modulations in the temporal and spectral envelope of the sound, we then show that noise invariance is partly achieved by selectively responding to long sounds with sharp spectral structure. Finally, to demonstrate that such computations could explain noise invariance, we designed a biologically inspired noise-filtering algorithm that can be used to separate song or speech from noise. This novel noise-filtering method performs as well as other state-of-the-art de-noising algorithms and could be used in clinical or consumer oriented applications. Our biologically inspired model also shows how high-level noise-invariant responses could be created from neural responses typically found in primary auditory cortex. PMID:23505354

  19. Noise suppression in duct

    International Nuclear Information System (INIS)

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

    2001-01-01

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

  20. Active3 noise reduction

    International Nuclear Information System (INIS)

    Holzfuss, J.

    1996-01-01

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

  1. Active noise cancellation algorithms for impulsive noise.

    Science.gov (United States)

    Li, Peng; Yu, Xun

    2013-04-01

    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 the results are presented and analyzed. The results show that the FXLMM and modified FXLMM algorithms are more robust in suppressing the adverse effect of sudden large amplitude impulses than FXLMS algorithm, and in particular, the proposed modified FXLMM algorithm can achieve better stability without sacrificing the performance of residual noise when encountering impulses.

  2. 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)....

  3. Cognitive-Motivational Determinants of Residents' Civic Engagement and Health (Inequities) in the Context of Noise Action Planning: A Conceptual Model.

    NARCIS (Netherlands)

    Riedel, Natalie; van Kamp, Irene; Köckler, Heike; Scheiner, Joachim; Loerbroks, Adrian; Claßen, Thomas; Bolte, Gabriele

    2017-01-01

    The Environmental Noise Directive expects residents to be actively involved in localising and selecting noise abatement interventions during the noise action planning process. Its intervention impact is meant to be homogeneous across population groups. Against the background of social heterogeneity

  4. Dim point target detection against bright background

    Science.gov (United States)

    Zhang, Yao; Zhang, Qiheng; Xu, Zhiyong; Xu, Junping

    2010-05-01

    For target detection within a large-field cluttered background from a long distance, several difficulties, involving low contrast between target and background, little occupancy, illumination ununiformity caused by vignetting of lens, and system noise, make it a challenging problem. The existing approaches to dim target detection can be roughly divided into two categories: detection before tracking (DBT) and tracking before detection (TBD). The DBT-based scheme has been widely used in practical applications due to its simplicity, but it often requires working in the situation with a higher signal-to-noise ratio (SNR). In contrast, the TBD-based methods can provide impressive detection results even in the cases of very low SNR; unfortunately, the large memory requirement and high computational load prevents these methods from real-time tasks. In this paper, we propose a new method for dim target detection. We address this problem by combining the advantages of the DBT-based scheme in computational efficiency and of the TBD-based in detection capability. Our method first predicts the local background, and then employs the energy accumulation and median filter to remove background clutter. The dim target is finally located by double window filtering together with an improved high order correlation which speeds up the convergence. The proposed method is implemented on a hardware platform and performs suitably in outside experiments.

  5. Preconditioner-free Wiener filtering with a dense noise matrix

    Science.gov (United States)

    Huffenberger, Kevin M.

    2018-05-01

    This work extends the Elsner & Wandelt (2013) iterative method for efficient, preconditioner-free Wiener filtering to cases in which the noise covariance matrix is dense, but can be decomposed into a sum whose parts are sparse in convenient bases. The new method, which uses multiple messenger fields, reproduces Wiener-filter solutions for test problems, and we apply it to a case beyond the reach of the Elsner & Wandelt (2013) method. We compute the Wiener-filter solution for a simulated Cosmic Microwave Background (CMB) map that contains spatially varying, uncorrelated noise, isotropic 1/f noise, and large-scale horizontal stripes (like those caused by atmospheric noise). We discuss simple extensions that can filter contaminated modes or inverse-noise-filter the data. These techniques help to address complications in the noise properties of maps from current and future generations of ground-based Microwave Background experiments, like Advanced ACTPol, Simons Observatory, and CMB-S4.

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

    International Nuclear Information System (INIS)

    1996-01-01

    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)

  7. Aerodynamical noise from wind turbine generators

    International Nuclear Information System (INIS)

    Jakobsen, J.; Andersen, B.

    1993-06-01

    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.)

  8. Estimating and Separating Noise from AIA Images

    Science.gov (United States)

    Kirk, Michael S.; Ireland, Jack; Young, C. Alex; Pesnell, W. Dean

    2016-10-01

    All digital images are corrupted by noise and SDO AIA is no different. In most solar imaging, we have the luxury of high photon counts and low background contamination, which when combined with carful calibration, minimize much of the impact noise has on the measurement. Outside high-intensity regions, such as in coronal holes, the noise component can become significant and complicate feature recognition and segmentation. We create a practical estimate of noise in the high-resolution AIA images across the detector CCD in all seven EUV wavelengths. A mixture of Poisson and Gaussian noise is well suited in the digital imaging environment due to the statistical distributions of photons and the characteristics of the CCD. Using state-of-the-art noise estimation techniques, the publicly available solar images, and coronal loop simulations; we construct a maximum-a-posteriori assessment of the error in these images. The estimation and mitigation of noise not only provides a clearer view of large-scale solar structure in the solar corona, but also provides physical constraints on fleeting EUV features observed with AIA.

  9. Noise Modeling of SDO AIA Images

    Science.gov (United States)

    Kirk, M. S.; Young, C. A.

    2014-12-01

    All digital images are corrupted by noise. In most solar imaging, we have the luxury of high photon counts and low background contamination, which when combined with carful calibration, minimize much of the impact noise has on the measurement. Outside high-intensity regions, such as in coronal holes, the noise component can become significant and complicate feature recognition and segmentation. We create a practical estimate of noise in the AIA images across the detector CCD. A Poisson-Gaussian model of noise is well suited in the digital imaging environment due to the statistical distributions of photons and the characteristics of the CCD. Using the dark and flat field calibration images, the level-1 AIA images, and readout noise measurements, we construct a maximum-a-posteriori estimation of the expected error in the AIA images. These estimations of noise not only provide a clearer view of solar features in AIA, but they are also relevant to error characterizations of other solar images.

  10. Noise control of radiological monitoring equipment

    International Nuclear Information System (INIS)

    Rubick, R.D.; Stevens, W.W.; Burke, L.L.

    1998-01-01

    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

  11. Health effects related to wind turbine noise exposure

    DEFF Research Database (Denmark)

    Schmidt, Jesper Hvass; Klokker, Mads

    2014-01-01

    BACKGROUND: Wind turbine noise exposure and suspected health-related effects thereof have attracted substantial attention. Various symptoms such as sleep-related problems, headache, tinnitus and vertigo have been described by subjects suspected of having been exposed to wind turbine noise...... existing statistically-significant evidence indicating any association between wind turbine noise exposure and tinnitus, hearing loss, vertigo or headache. LIMITATIONS: Selection bias and information bias of differing magnitudes were found to be present in all current studies investigating wind turbine...

  12. Concerning background from calorimeter ports

    International Nuclear Information System (INIS)

    Digiacomo, N.J.

    1985-01-01

    Any detector system viewing a port or slit in a calorimeter wall will see, in addition to the primary particles of interest, a background of charged and neutral particles and photons generated by scattering from the port walls and by leakage from incompletely contained primary particle showers in the calorimeter near the port. The signal to noise ratio attainable outside the port is a complex function of the primary source spectrum, the calorimeter and port design and, of course, the nature and acceptance of the detector system that views the port. Rather than making general statements about the overall suitability (or lack thereof) of calorimeter ports, we offer here a specific example based on the external spectrometer and slit of the NA34 experiment. This combination of slit and spectrometer is designed for fixed-target work, so that the primary particle momentum spectrum contains higher momentum particles than expected in a heavy ion colliding beam environment. The results are, nevertheless, quite relevant for the collider case

  13. Signs of noise-induced neural degeneration in humans

    DEFF Research Database (Denmark)

    Holtegaard, Pernille; Olsen, Steen Østergaard

    2015-01-01

    Animal studies demonstrated that noise exposure causes a primary and selective loss of auditory-nerve fibres with low spontaneous firing rate. This neuronal impairment, if also present in humans, can be assumed to affect the processing of supra-threshold stimuli, especially in the presence...... of 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...

  14. Background Rejection in the ARA Experiment

    Directory of Open Access Journals (Sweden)

    Pfendner Carl

    2017-01-01

    Full Text Available The Askaryan Radio Array (ARA is a radio frequency observatory under construction at the South Pole that is searching for ultrahigh energy neutrinos via the Askaryan effect. Thermal fluctuations currently dominate the trigger-level background for the observatory and anthropogenic sources also introduce a significant source of noise. By taking advantage of the observatory’s regular geometry and the expected coincident nature of the RF signals arriving from neutrino-induced events, this background can be filtered efficiently. This contribution will discuss techniques developed for the ARA analyses to reject these thermal signals, to reject anthropogenic backgrounds, and to search for neutrino-induced particle showers in the Antarctic ice. The results of a search for neutrinos from GRBs using the prototype station using some of these techniques will be presented.

  15. The Cosmic Background Explorer

    Science.gov (United States)

    Gulkis, Samuel; Lubin, Philip M.; Meyer, Stephan S.; Silverberg, Robert F.

    1990-01-01

    The Cosmic Background Explorer (CBE), NASA's cosmological satellite which will observe a radiative relic of the big bang, is discussed. The major questions connected to the big bang theory which may be clarified using the CBE are reviewed. The satellite instruments and experiments are described, including the Differential Microwave Radiometer, which measures the difference between microwave radiation emitted from two points on the sky, the Far-Infrared Absolute Spectrophotometer, which compares the spectrum of radiation from the sky at wavelengths from 100 microns to one cm with that from an internal blackbody, and the Diffuse Infrared Background Experiment, which searches for the radiation from the earliest generation of stars.

  16. The natural radiation background

    International Nuclear Information System (INIS)

    Duggleby, J.C.

    1982-01-01

    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

  17. 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.

  18. Adaptive noise cancellation

    International Nuclear Information System (INIS)

    Akram, N.

    1999-01-01

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

  19. 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.

  20. Effect of external classroom noise on schoolchildren's reading and mathematics performance: correlation of noise levels and gender.

    Science.gov (United States)

    Papanikolaou, M; Skenteris, N; Piperakis, S M

    2015-02-01

    The present study investigated the effect of low, medium, and high traffic road noise as well as irrelevant background speech noise on primary school children's reading and mathematical performance. A total of 676 participants (324 boys, 47.9% and 352 girls, 52.1%) of the 4th and 5th elementary classes participated in the project. The participants were enrolled in public primary schools from urban areas and had ages ranging from 9 to 10 years and from. Schools were selected on the basis of increasing levels of exposure to road traffic noise and then classified into three categories (Low noise: 55-66 dB, Medium noise: 67-77 dB, and High noise: 72-80 dB). We measured reading comprehension and mathematical skills in accordance with the national guidelines for elementary education, using a test designed specifically for the purpose of this study. On the one hand, children in low-level noise schools showed statistically significant differences from children in medium- and high-level noise schools in reading performance (p<0.001). On the other hand, children in low-level noise schools differed significantly from children in high-level noise schools but only in mathematics performance (p=0.001). Girls in general did better in reading score than boys, especially in schools with medium- and high-level noise. Finally the levels of noise and gender were found to be two independent factors.

  1. Noise Induced Hearing Loss among Khartoum International Airport ...

    African Journals Online (AJOL)

    Background: Noise-induced hearing loss [NIHL] was incriminated to be the second most common sensorineural hearing loss, after age-related hearing loss. Objective: This study aimed to investigate noise induced hearing loss among employees of Khartoum international air port. Material and Methods: The study ...

  2. Impact of noise and air pollution on pregnancy outcomes

    NARCIS (Netherlands)

    Gehring, Ulrike|info:eu-repo/dai/nl/304831344; Tamburic, Lillian; Sbihi, Hind; Davies, Hugh W.; Brauer, Michael

    2014-01-01

    Background: Motorized traffic is an important source of both air pollution and community noise. While there is growing evidence for an adverse effect of ambient air pollution on reproductive health, little is known about the association between traffic noise and pregnancy outcomes. Methods: We

  3. Trajectories of Brownian particles with space-correlated noise

    Indian Academy of Sciences (India)

    EDOARDO MILOTTI

    walks with spatially correlated white noise: the time- dependence of the distance of ... Dedicated to the memory of the late Professor Charusita Chakravarty. also quite well-known that the ..... Paths of two 2D random walkers (marked in red and blue) in a background of space-correlated noise. The simu- lated random fields ...

  4. Landing gear noise attenuation

    Science.gov (United States)

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

    2011-01-01

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

  5. Noise in biological circuits.

    Science.gov (United States)

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

    2009-01-01

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

  6. 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...

  7. Nonthermal cosmic neutrino background

    Science.gov (United States)

    Chen, Mu-Chun; Ratz, Michael; Trautner, Andreas

    2015-12-01

    We point out that, for Dirac neutrinos, in addition to the standard thermal cosmic neutrino background (C ν B ), there could also exist a nonthermal neutrino background with comparable number density. As the right-handed components are essentially decoupled from the thermal bath of standard model particles, relic neutrinos with a nonthermal distribution may exist until today. The relic density of the nonthermal (nt) background can be constrained by the usual observational bounds on the effective number of massless degrees of freedom Neff and can be as large as nν nt≲0.5 nγ. In particular, Neff can be larger than 3.046 in the absence of any exotic states. Nonthermal relic neutrinos constitute an irreducible contribution to the detection of the C ν B and, hence, may be discovered by future experiments such as PTOLEMY. We also present a scenario of chaotic inflation in which a nonthermal background can naturally be generated by inflationary preheating. The nonthermal relic neutrinos, thus, may constitute a novel window into the very early Universe.

  8. The influence of amplifier, interface and biological noise on signal quality in high-resolution EEG recordings.

    Science.gov (United States)

    Scheer, Hans J; Sander, Tilmann; Trahms, Lutz

    2006-02-01

    First, the intrinsic random noise sources of a biopotential measurement in general are reviewed. For the special case of an electroencephalographic (EEG) measurement we have extended the commonly used amplifier noise model by biological generated background noise. As the strongest of all noise sources involved will dominate the resulting signal to noise ratio (S/N), we have investigated under which conditions this will be the case. We illustrate experimentally that up to 100 Hz S/N practically depends only on cortical generated background noise, while at a few hundred Hz or more amplifier and thermal noise of interelectrode resistance are the major sources.

  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. Noise and Health: How does noise affect us?

    NARCIS (Netherlands)

    Miedema, H.M.E.

    2001-01-01

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

  11. Interventions to prevent occupational noise induced hearing loss

    NARCIS (Netherlands)

    Verbeek, Jos H.; Kateman, Erik; Morata, Thais C.; Dreschler, Wout; Sorgdrager, Bas

    2009-01-01

    BACKGROUND: Millions of workers worldwide are exposed to noise levels that increase their risk of hearing impairment. Little is known about the effectiveness of hearing loss prevention interventions. OBJECTIVES: To assess the effectiveness of non-pharmaceutical interventions for preventing

  12. Interventions to prevent occupational noise-induced hearing loss

    NARCIS (Netherlands)

    Verbeek, Jos H.; Kateman, Erik; Morata, Thais C.; Dreschler, Wouter A.; Mischke, Christina

    2012-01-01

    Background Millions of workers worldwide are exposed to noise levels that increase their risk of hearing impairment. Little is known about the effectiveness of hearing loss prevention interventions. Objectives To assess the effectiveness of non-pharmaceutical interventions for preventing

  13. Particle and Noise Exposure During Highway Maintenance Work

    Science.gov (United States)

    Background: Exposure to traffic is associated with increased cardiovascular morbidity and mortality. Traffic particles are associated with increased pro‑inflammatory and pro-thrombotic markers as well as altered heart rhythm (Riediker et al. 2004). Occupational noise exposu...

  14. Background of SAM atom-fraction profiles

    International Nuclear Information System (INIS)

    Ernst, Frank

    2017-01-01

    Atom-fraction profiles acquired by SAM (scanning Auger microprobe) have important applications, e.g. in the context of alloy surface engineering by infusion of carbon or nitrogen through the alloy surface. However, such profiles often exhibit an artifact in form of a background with a level that anti-correlates with the local atom fraction. This article presents a theory explaining this phenomenon as a consequence of the way in which random noise in the spectrum propagates into the discretized differentiated spectrum that is used for quantification. The resulting model of “energy channel statistics” leads to a useful semi-quantitative background reduction procedure, which is validated by applying it to simulated data. Subsequently, the procedure is applied to an example of experimental SAM data. The analysis leads to conclusions regarding optimum experimental acquisition conditions. The proposed method of background reduction is based on general principles and should be useful for a broad variety of applications. - Highlights: • Atom-fraction–depth profiles of carbon measured by scanning Auger microprobe • Strong background, varies with local carbon concentration. • Needs correction e.g. for quantitative comparison with simulations • Quantitative theory explains background. • Provides background removal strategy and practical advice for acquisition

  15. Non-collision backgrounds in ATLAS

    CERN Document Server

    Gibson, S M; The ATLAS collaboration

    2012-01-01

    The proton-proton collision events recorded by the ATLAS experiment are on top of a background that is due to both collision debris and non-collision components. The latter comprises of three types: beam-induced backgrounds, cosmic particles and detector noise. We present studies that focus on the first two of these. We give a detailed description of beam-related and cosmic backgrounds based on the full 2011 ATLAS data set, and present their rates throughout the whole data-taking period. Studies of correlations between tertiary proton halo and muon backgrounds, as well as, residual pressure and resulting beam-gas events seen in beam-condition monitors will be presented. Results of simulations based on the LHC geometry and its parameters will be presented. They help to better understand the features of beam-induced backgrounds in each ATLAS sub-detector. The studies of beam-induced backgrounds in ATLAS reveal their characteristics and serve as a basis for designing rejection tools that can be applied in physic...

  16. 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.

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

    NARCIS (Netherlands)

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

    2014-01-01

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

  18. 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 al...

  19. Noise in miniature microphones.

    Science.gov (United States)

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

    2002-02-01

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

  20. 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).

  1. 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...

  2. 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.

  3. Noise from wind turbines

    International Nuclear Information System (INIS)

    Andersen, B.; Jakobsen, J.

    1992-11-01

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

  4. Noise from wind turbines

    International Nuclear Information System (INIS)

    Andersen, B.; Larsen, P.

    1993-01-01

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

  5. [Urban noise pollution].

    Science.gov (United States)

    Chouard, C H

    2001-07-01

    Noise is responsible for cochlear and general damages. Hearing loss and tinnitus greatly depend on sound intensity and duration. Short-duration sound of sufficient intensity (gunshot or explosion) will not be described because they are not currently encountered in our normal urban environment. Sound levels of less than 75 d (A) are unlikely to cause permanent hearing loss, while sound levels of about 85 d (A) with exposures of 8 h per day will produce permanent hearing loss after many years. Popular and largely amplified music is today one of the most dangerous causes of noise induced hearing loss. The intensity of noises (airport, highway) responsible for stress and general consequences (cardiovascular) is generally lower. Individual noise sensibility depends on several factors. Strategies to prevent damage from sound exposure should include the use of individual hearing protection devices, education programs beginning with school-age children, consumer guidance, increased product noise labelling, and hearing conservation programs for occupational settings.

  6. 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

  7. 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....

  8. 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 organisations...... 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/value: This chapter takes a look...

  9. 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 recen...

  10. Noise and Hearing Loss Prevention

    Science.gov (United States)

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

  11. Noise pollution changes avian communities and species interactions.

    Science.gov (United States)

    Francis, Clinton D; Ortega, Catherine P; Cruz, Alexander

    2009-08-25

    Humans have drastically changed much of the world's acoustic background with anthropogenic sounds that are markedly different in pitch and amplitude than sounds in most natural habitats. This novel acoustic background may be detrimental for many species, particularly birds. We evaluated conservation concerns that noise limits bird distributions and reduces nesting success via a natural experiment to isolate the effects of noise from confounding stimuli and to control for the effect of noise on observer detection biases. We show that noise alone reduces nesting species richness and leads to different avian communities. Contrary to expectations, noise indirectly facilitates reproductive success of individuals nesting in noisy areas as a result of the disruption of predator-prey interactions. The higher reproductive success for birds within noisy habitats may be a previously unrecognized factor contributing to the success of urban-adapted species and the loss of birds less tolerant of noise. Additionally, our findings suggest that noise can have cascading consequences for communities through altered species interactions. Given that noise pollution is becoming ubiquitous throughout much of the world, knowledge of species-specific responses to noise and the cumulative effects of these novel acoustics may be crucial to understanding and managing human-altered landscapes.

  12. Handbook Of Noise And Vibration

    International Nuclear Information System (INIS)

    1995-12-01

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

  13. 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…

  14. Simultaneous exposure to ethyl benzene and noise : synergistic effects on outer hair cells

    NARCIS (Netherlands)

    Cappaert, N.L.M.; Klis, S.F.L.; Muijser, H.; Kulig, B.M.; Smoorenburg, G.F.

    2001-01-01

    The effects on hearing of simultaneous exposure to the ototoxic organic solvent ethyl benzene and broad-band noise were evaluated in rats. The effects of three ethyl benzene concentrations (0, 300 or 400 ppm) and three noise levels (95 or 105 dBlin SPL or background noise at 65 dBlin SPL) and all

  15. Proceedings of a workshop on wind turbine noise

    International Nuclear Information System (INIS)

    Legerton, M.

    1993-08-01

    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. 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.

  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. Alien Noise Cancellation

    Indian Academy of Sciences (India)

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

  19. Airframe noise prediction evaluation

    Science.gov (United States)

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

    1995-01-01

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

  20. Acoustic ambient noise recorder

    Digital Repository Service at National Institute of Oceanography (India)

    Saran, A.K.; Navelkar, G.S.; Almeida, A.M.; More, S.R.; Chodankar, P.V.; Murty, C.S.

    with a robust outfit that can withstand high pressures and chemically corrosion resistant materials. Keeping these considerations in view, a CMOS micro-controller-based marine acoustic ambient noise recorder has been developed with a real time clock...

  1. A Measurement of the Cosmic Microwave Background Temperature ...

    Indian Academy of Sciences (India)

    tribpo

    Cosmic Microwave Background Temperature at 1280 MHz. 5. Figure 3. Photograph of the 1280 MHz receiver with the aluminium shield lowered to the ground. 3. Noise reduction techniques. The circulator has been introduced at the input of the LNA in order to isolate the. LNA from reflections in the corrugated plate OMT ...

  2. Approximations to camera sensor noise

    Science.gov (United States)

    Jin, Xiaodan; Hirakawa, Keigo

    2013-02-01

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

  3. Noise Abatement Materials

    Science.gov (United States)

    1986-01-01

    A former NASA employee who discovered a kind of plastic that soaked up energy, dampened vibrations, and was a good noise abatement material, founded a company to market noise deadening adhesives, sheets, panels and enclosures. Known as SMART products, they are 75-80% lighter than ordinary soundproofing material and have demonstrated a high degree of effectiveness. The company, Varian Associates, makes enclosures for high voltage terminals and other electronic system components, and easily transportable audiometric test booths.

  4. Active noise control primer

    CERN Document Server

    Snyder, Scott D

    2000-01-01

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

  5. 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...

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

    International Nuclear Information System (INIS)

    1993-04-01

    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

  7. Impact of chronic noise exposure on antipredator behavior: an experiment in breeding house sparrows

    OpenAIRE

    Alizée Meillère; François Brischoux; Frédéric Angelier

    2015-01-01

    Over the last century, expanding urbanization has led to a strong increase in the levels of background noise. This noise pollution has been shown to negatively affect wildlife (e.g., reduced species diversity and density, reduced breeding success), especially birds. Most research addressing the effects of anthropogenic noise has focused on avian communication and, to date, very little is known regarding the impact of chronic noise exposure on nonvocal behavior such as antipredator behavior. H...

  8. Effects of exposure to noise and indoor air pollution on human perception and symptoms

    DEFF Research Database (Denmark)

    Witterseh, Thomas; Wargocki, Pawel; Fang, Lei

    1999-01-01

    The objective of the present study was to investigate human perception and SBS symptoms when people are exposed simultaneously to different levels of air pollution and ventilation noise. The air quality in an office was modified by placing or removing a carpet and the background noise level...... of ventilation noise (with a neutral frequency spectrum) from 42 dB(A) to 45 dB(A) had a strong impact on the percentage of persons dissatisfied due to noise....

  9. Evaluation of internal noise methods for Hotelling observer models

    International Nuclear Information System (INIS)

    Zhang Yani; Pham, Binh T.; Eckstein, Miguel P.

    2007-01-01

    The inclusion of internal noise in model observers is a common method to allow for quantitative comparisons between human and model observer performance in visual detection tasks. In this article, we studied two different strategies for inserting internal noise into Hotelling model observers. In the first strategy, internal noise was added to the output of individual channels: (a) Independent nonuniform channel noise, (b) independent uniform channel noise. In the second strategy, internal noise was added to the decision variable arising from the combination of channel responses. The standard deviation of the zero mean internal noise was either constant or proportional to: (a) the decision variable's standard deviation due to the external noise, (b) the decision variable's variance caused by the external noise, (c) the decision variable magnitude on a trial to trial basis. We tested three model observers: square window Hotelling observer (HO), channelized Hotelling observer (CHO), and Laguerre-Gauss Hotelling observer (LGHO) using a four alternative forced choice (4AFC) signal known exactly but variable task with a simulated signal embedded in real x-ray coronary angiogram backgrounds. The results showed that the internal noise method that led to the best prediction of human performance differed across the studied model observers. The CHO model best predicted human observer performance with the channel internal noise. The HO and LGHO best predicted human observer performance with the decision variable internal noise. The present results might guide researchers with the choice of methods to include internal noise into Hotelling model observers when evaluating and optimizing medical image quality

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

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  11. Noise sensitivity and sleep disturbance

    NARCIS (Netherlands)

    Laszlo, H.E.; Janssen, S.A.; Babisch, W.; Hansell, A.L.

    2012-01-01

    It has been shown that noise induced health effects are strongly related to non-acoustical factors such as noise sensitivity. It is a stable personality trait and it can be conceptualised as a causal pathway confounder and/or effect modifier between noise and health. Furthermore noise sensitivity

  12. 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.

  13. Noise measurement in wind tunnels, workshop summary

    Science.gov (United States)

    Hickley, D. H.; Williams, J.

    1982-09-01

    In reviewing the progress made in acoustic measurements in wind tunnels over the 5-yr span of the workshops, it is evident that a great deal of progress has occurred. Specialized facilities are now on line, special measurement techniques were developed, and corrections were devised and proven. This capability is in the process of creating a new and more correct data bank on acoustic phenomena, and represents a major step forward in acoustics technology. Additional work is still required, but now, rather than concentrating on facilities and techniques, researchers may more profitably concentrate on noise-source modeling, with the simulation of propulsor noise source (in flight) and of propulsor/airframe airflow characteristics. Promising developments in directional acoustic receivers and other discrimination/correlation techniques should now be regularly exploited, in part for model noise-source diagnosis, but also to expedite extraction of the lone source signal from any residual background noise and reverberation in the working chamber and from parasitic noise due to essential rigs or instrumentation inside the airstream.

  14. Seismic noise level variation in South Korea

    Science.gov (United States)

    Sheen, D.; Shin, J.

    2008-12-01

    The variations of seismic background noise in South Korea have been investigated by means of power spectral analysis. The Korea Institute of Geoscience and Mineral Resources (KIGAM) and the Korea Meteorological Administation (KMA) have national wide seismic networks in South Korea, and, in the end of 2007, there are 30 broadband stations which have been operating for more than a year. In this study, we have estimated the power spectral density of seismic noise for 30 broadband stations from 2005 to 2007. Since we estimate PSDs from a large dataset of continuous waveform in this study, a robust PSD estimate of McNamara and Buland (2004) is used. In the frequency range 1-5 Hz, the diurnal variations of noise are observed at most of stations, which are especially larger at coastal stations and at insular than at inland. Some stations shows daily difference of diurnal variations, which represents that cultural activities contribute to the noise level of a station. The variation of number of triggered stations, however, shows that cultural noise has little influence on the detection capability of seismic network in South Korea. Seasonal variations are observed well in the range 0.1-0.5 Hz, while much less found in the frequency range 1-5 Hz. We observed that strong peaks in the range 0.1-0.5 Hz occur at the summer when Pacific typhoons are close to the Korean Peninsula.

  15. The effects of different noise types on heart rate variability in men.

    Science.gov (United States)

    Sim, Chang Sun; Sung, Joo Hyun; Cheon, Sang Hyeon; Lee, Jang Myung; Lee, Jae Won; Lee, Jiho

    2015-01-01

    To determine the impact of noise on heart rate variability (HRV) in men, with a focus on the noise type rather than on noise intensity. Forty college-going male volunteers were enrolled in this study and were randomly divided into four groups according to the type of noise they were exposed to: background, traffic, speech, or mixed (traffic and speech) noise. All groups except the background group (35 dB) were exposed to 45 dB sound pressure levels. We collected data on age, smoking status, alcohol consumption, and disease status from responses to self-reported questionnaires and medical examinations. We also measured HRV parameters and blood pressure levels before and after exposure to noise. The HRV parameters were evaluated while patients remained seated for 5 minutes, and frequency and time domain analyses were then performed. After noise exposure, only the speech noise group showed a reduced low frequency (LF) value, reflecting the activity of both the sympathetic and parasympathetic nervous systems. The low-to-high frequency (LF/HF) ratio, which reflected the activity of the autonomic nervous system (ANS), became more stable, decreasing from 5.21 to 1.37; however, this change was not statistically significant. These results indicate that 45 dB(A) of noise, 10 dB(A) higher than background noise, affects the ANS. Additionally, the impact on HRV activity might differ according to the noise quality. Further studies will be required to ascertain the role of noise type.

  16. Suprathreshold perception of tonal components in noise under conditions of masking release

    OpenAIRE

    Verhey, Jesko L.; Heise, Stephan J.

    2012-01-01

    Many technical sounds contain tonal components in a noise background. The present study investigates how such tonal components embedded in noise are perceived under conditions of enhanced detectability of the tone due to (i) amplitude modulation of the noise background or (ii) interaural disparities in the signal's phase. To quantify the sensation elicited by a tonal component in these masking-release conditions, the listeners are asked to adjust the level of the tone to have the same magnitu...

  17. Reducing noise in uranium exploration

    International Nuclear Information System (INIS)

    Ward, W.J. III.

    1977-01-01

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

  18. Noise in the operating room

    DEFF Research Database (Denmark)

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

    2010-01-01

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

  19. Resistive Switching Assisted by Noise

    OpenAIRE

    Patterson, G. A.; Fierens, P. I.; Grosz, D. F.

    2013-01-01

    We extend results by Stotland and Di Ventra on the phenomenon of resistive switching aided by noise. We further the analysis of the mechanism underlying the beneficial role of noise and study the EPIR (Electrical Pulse Induced Resistance) ratio dependence with noise power. In the case of internal noise we find an optimal range where the EPIR ratio is both maximized and independent of the preceding resistive state. However, when external noise is considered no beneficial effect is observed.

  20. Enhancement of information transmission with stochastic resonance in hippocampal CA1 neuron models: effects of noise input location.

    Science.gov (United States)

    Kawaguchi, Minato; Mino, Hiroyuki; Durand, Dominique M

    2007-01-01

    Stochastic resonance (SR) has been shown to enhance the signal to noise ratio or detection of signals in neurons. It is not yet clear how this effect of SR on the signal to noise ratio affects signal processing in neural networks. In this paper, we investigate the effects of the location of background noise input on information transmission in a hippocampal CA1 neuron model. In the computer simulation, random sub-threshold spike trains (signal) generated by a filtered homogeneous Poisson process were presented repeatedly to the middle point of the main apical branch, while the homogeneous Poisson shot noise (background noise) was applied to a location of the dendrite in the hippocampal CA1 model consisting of the soma with a sodium, a calcium, and five potassium channels. The location of the background noise input was varied along the dendrites to investigate the effects of background noise input location on information transmission. The computer simulation results show that the information rate reached a maximum value for an optimal amplitude of the background noise amplitude. It is also shown that this optimal amplitude of the background noise is independent of the distance between the soma and the noise input location. The results also show that the location of the background noise input does not significantly affect the maximum values of the information rates generated by stochastic resonance.

  1. Engineering out the noise.

    Science.gov (United States)

    Yankaskas, Kurt; Fischer, Raymond; Spence, Jesse; Komrower, Jeffrey

    2017-06-01

    The US Navy, through an Office of Naval Research (ONR) lead effort on Noise Induced Hearing Loss (NIHL), is investigating methods and techniques to mitigate hearing loss for the crews and warfighters. Hearing protection is a viable and increasingly popular method of reducing hearing exposure for many ship crew members; however, it has limitations on comfort and low frequency effectiveness. Furthermore, Personal Hearing Protection (PHP) is often used improperly. Proper vessel planning, programmatic changes and advances in noise control engineering can also have significant impacts by inherently reducing noise exposure through ship design and use of noise control treatments. These impacts go beyond hearing loss mitigation since they can improve quality of life onboard vessels and provide enhanced warfighter performance. Such approaches also can be made to work in the lower frequency range where hearing protection is not as effective. This paper describes non-hearing protection methods being implemented to mitigate and control noise within the US Navy and US Marine Corps. These approaches reflect the latest changes to Mil-Std 1474E, Appendix F. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. 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.

  3. 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. © 2014 The Authors. Scandinavian Journal of Psychology published by Scandinavian Psychological Associations and John Wiley & Sons Ltd.

  4. Noise-gating to Clean Astrophysical Image Data

    Energy Technology Data Exchange (ETDEWEB)

    DeForest, C. E. [Southwest Research Institute, 1050 Walnut Street, Boulder, CO (United States)

    2017-04-01

    I present a family of algorithms to reduce noise in astrophysical images and image sequences, preserving more information from the original data than is retained by conventional techniques. The family uses locally adaptive filters (“noise gates”) in the Fourier domain to separate coherent image structure from background noise based on the statistics of local neighborhoods in the image. Processing of solar data limited by simple shot noise or by additive noise reveals image structure not easily visible in the originals, preserves photometry of observable features, and reduces shot noise by a factor of 10 or more with little to no apparent loss of resolution. This reveals faint features that were either not directly discernible or not sufficiently strongly detected for quantitative analysis. The method works best on image sequences containing related subjects, for example movies of solar evolution, but is also applicable to single images provided that there are enough pixels. The adaptive filter uses the statistical properties of noise and of local neighborhoods in the data to discriminate between coherent features and incoherent noise without reference to the specific shape or evolution of those features. The technique can potentially be modified in a straightforward way to exploit additional a priori knowledge about the functional form of the noise.

  5. 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.

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

    Directory of Open Access Journals (Sweden)

    Jangho Park

    2017-04-01

    Full Text Available Abstract Background Excessive noise affects human health and interferes with daily activities. Although environmental noise may not directly cause mental illness, it may accelerate and intensify the development of latent mental disorders. Noise sensitivity (NS is considered a moderator of non-auditory noise effects. In the present study, we aimed to assess whether NS is associated with non-auditory effects. Methods We recruited a community sample of 1836 residents residing in Ulsan and Seoul, South Korea. From July to November 2015, participants were interviewed regarding their demographic characteristics, socioeconomic status, medical history, and NS. The non-auditory effects of noise were assessed using the Center of Epidemiologic Studies Depression, Insomnia Severity index, State Trait Anxiety Inventory state subscale, and Stress Response Inventory-Modified Form. Individual noise levels were recorded from noise maps. A three-model multivariate logistic regression analysis was performed to identify factors that might affect psychiatric illnesses. Results Participants ranged in age from 19 to 91 years (mean: 47.0 ± 16.1 years, and 37.9% (n = 696 were male. Participants with high NS were more likely to have been diagnosed with diabetes and hyperlipidemia and to use psychiatric medication. The multivariable analysis indicated that even after adjusting for noise-related variables, sociodemographic factors, medical illness, and duration of residence, subjects in the high NS group were more than 2 times more likely to experience depression and insomnia and 1.9 times more likely to have anxiety, compared with those in the low NS group. Noise exposure level was not identified as an explanatory value. Conclusions NS increases the susceptibility and hence moderates there actions of individuals to noise. NS, rather than noise itself, is associated with an elevated susceptibility to non-auditory effects.

  7. Joyce’s Noises

    Directory of Open Access Journals (Sweden)

    Derek Attridge

    2009-10-01

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

  8. Noise and Tinnitus

    Directory of Open Access Journals (Sweden)

    Mansoureh Adel Ghahraman

    1999-03-01

    Full Text Available Tinnitus from the Latin word tinnire meaning ringing is the perception of sound within the human ear in the absence of corresponding external sound. The most common cause is noise induced hearing loss. Tinnitus may be induced by an acoustic trauma or a permanent noise in the workplace. In case that Tinnitus is induced by acoustic trauma the site of lesion is commonly the base of the cochlea. Tinnitus in the senile population is mostly accompanying presbycusis. Although the incidence of permanent tinnitus following noise exposure is high, little is published about this issue. In the current article we are aimed at studying the prevalence of tinnitus in Minoo and other manufactures.

  9. Star point centroid algorithm based on background forecast

    Science.gov (United States)

    Wang, Jin; Zhao, Rujin; Zhu, Nan

    2014-09-01

    The calculation of star point centroid is a key step of improving star tracker measuring error. A star map photoed by APS detector includes several noises which have a great impact on veracity of calculation of star point centroid. Through analysis of characteristic of star map noise, an algorithm of calculation of star point centroid based on background forecast is presented in this paper. The experiment proves the validity of the algorithm. Comparing with classic algorithm, this algorithm not only improves veracity of calculation of star point centroid, but also does not need calibration data memory. This algorithm is applied successfully in a certain star tracker.

  10. Executive Summary - Historical background

    International Nuclear Information System (INIS)

    2005-01-01

    matter physics experiments at the High Flux Reactor of The Laue Langevin Institute and the ISIS spallation source at Rutherford-Appleton. Recently, we very actively entered the ICARUS neutrino collaboration and were invited to the PIERRE AUGER collaboration which will search for the highest energies in the Universe. Having close ties with CERN we are very actively engaged in CROSS-GRID, a large computer network project. To better understand the historical background of the INP development, it is necessary to add a few comments on financing of science in Poland. During the 70's and the 80's, research was financed through the so-called Central Research Projects for Science and Technical Development. The advantage of this system was that state-allocated research funds were divided only by a few representatives of the scientific community, which allowed realistic allocation of money to a small number of projects. After 1989 we were able to purchase commercially available equipment, which led to the closure of our large and very experienced electronic workshop. We also considerably reduced our well equipped mechanical shop. During the 90's the reduced state financing of science was accompanied by a newly established Committee of Scientific Research which led to the creation of a system of small research projects. This precluded the development of more ambitious research projects and led to the dispersion of equipment among many smaller laboratories and universities. A large research establishment, such as our Institute, could not develop properly under such conditions. In all, between 1989 and 2004 we reduced our personnel from about 800 to 470 and our infrastructure became seriously undercapitalised. However, with energetic search for research funds, from European rather than national research programs, we hope to improve and modernize our laboratories and their infrastructure in the coming years

  11. Maximum noise abatement trajectories.

    Science.gov (United States)

    Zeldin, S.; Speyer, J.

    1972-01-01

    Minimum noise annoyance trajectories for developing STOL operation procedures are obtained by modulating five control variables in two dimensions. The performance index is formulated such that it explicitly assigns the same relative importance to thrust as it does to distances between discrete listeners and the aircraft. However, using a steepest descent optimization program, results indicate that it is preferable to keep the thrusters at their maximum value to minimize the integrated annoyance rather than to reduce thrust which would lower the instantaneous annoyance. Thrust decreases below its bound only when the instantaneous noise at a listener is limited.

  12. 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.

  13. 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.

  14. Description of Anomalous Noise Events for Reliable Dynamic Traffic Noise Mapping in Real-Life Urban and Suburban Soundscapes

    Directory of Open Access Journals (Sweden)

    Francesc Alías

    2017-02-01

    Full Text Available Traffic noise is one of the main pollutants in urban and suburban areas. European authorities have driven several initiatives to study, prevent and reduce the effects of exposure of population to traffic. Recent technological advances have allowed the dynamic computation of noise levels by means of Wireless Acoustic Sensor Networks (WASN such as that developed within the European LIFE DYNAMAP project. Those WASN should be capable of detecting and discarding non-desired sound sources from road traffic noise, denoted as anomalous noise events (ANE, in order to generate reliable noise level maps. Due to the local, occasional and diverse nature of ANE, some works have opted to artificially build ANE databases at the cost of misrepresentation. This work presents the production and analysis of a real-life environmental audio database in two urban and suburban areas specifically conceived for anomalous noise events’ collection. A total of 9 h 8 min of labelled audio data is obtained differentiating among road traffic noise, background city noise and ANE. After delimiting their boundaries manually, the acoustic salience of the ANE samples is automatically computed as a contextual signal-to-noise ratio (SNR. The analysis of the real-life environmental database shows high diversity of ANEs in terms of occurrences, durations and SNRs, as well as confirming both the expected differences between the urban and suburban soundscapes in terms of occurrences and SNRs, and the rare nature of ANE.

  15. Maximizing noise energy for noise-masking studies.

    Science.gov (United States)

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

    2017-08-01

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

  16. Noise pollution is pervasive in U.S. protected areas.

    Science.gov (United States)

    Buxton, Rachel T; McKenna, Megan F; Mennitt, Daniel; Fristrup, Kurt; Crooks, Kevin; Angeloni, Lisa; Wittemyer, George

    2017-05-05

    Anthropogenic noise threatens ecological systems, including the cultural and biodiversity resources in protected areas. Using continental-scale sound models, we found that anthropogenic noise doubled background sound levels in 63% of U.S. protected area units and caused a 10-fold or greater increase in 21%, surpassing levels known to interfere with human visitor experience and disrupt wildlife behavior, fitness, and community composition. Elevated noise was also found in critical habitats of endangered species, with 14% experiencing a 10-fold increase in sound levels. However, protected areas with more stringent regulations had less anthropogenic noise. Our analysis indicates that noise pollution in protected areas is closely linked with transportation, development, and extractive land use, providing insight into where mitigation efforts can be most effective. Copyright © 2017, American Association for the Advancement of Science.

  17. Effects of amplitude modulation on perception of wind turbine noise

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Ki Seop; Lee, Soo Gab; Gwak, Doo Young [Dept. of Mechanical and Aerospace Engineering, Seoul National University, Seoul (Korea, Republic of); Seong, Yeol Wan [Ammunition Engineering Team, Defense Agency for Technology and Quality, Daejeon (Korea, Republic of); Lee, Seung Hoon [Aerodynamics Research Team, Korea Aerospace Research Institute, Daejeon (Korea, Republic of); Hong, Ji Young [Transportation Environmental Research Team, Green Transport and Logistics Institute, Korea Railroad Research Institute, Uiwang (Korea, Republic of)

    2016-10-15

    Wind turbine noise is considered to be easily detectable and highly annoying at relatively lower sound levels than other noise sources. Many previous studies attributed this characteristic to amplitude modulation. However, it is unclear whether amplitude modulation is the main cause of these properties of wind turbine noise. Therefore, the aim of the current study is to identify the relationship between amplitude modulation and these two properties of wind turbine noise. For this investigation, two experiments were conducted. In the first experiment, 12 participants determined the detection thresholds of six target sounds in the presence of background noise. In the second experiment, 12 participants matched the loudness of modified sounds without amplitude modulation to that of target sounds with amplitude modulation. The results showed that the detection threshold was lowered as the modulation depth increased; additionally, sounds with amplitude modulation had higher subjective loudness than those without amplitude modulation.

  18. Effects of amplitude modulation on perception of wind turbine noise

    International Nuclear Information System (INIS)

    Yoon, Ki Seop; Lee, Soo Gab; Gwak, Doo Young; Seong, Yeol Wan; Lee, Seung Hoon; Hong, Ji Young

    2016-01-01

    Wind turbine noise is considered to be easily detectable and highly annoying at relatively lower sound levels than other noise sources. Many previous studies attributed this characteristic to amplitude modulation. However, it is unclear whether amplitude modulation is the main cause of these properties of wind turbine noise. Therefore, the aim of the current study is to identify the relationship between amplitude modulation and these two properties of wind turbine noise. For this investigation, two experiments were conducted. In the first experiment, 12 participants determined the detection thresholds of six target sounds in the presence of background noise. In the second experiment, 12 participants matched the loudness of modified sounds without amplitude modulation to that of target sounds with amplitude modulation. The results showed that the detection threshold was lowered as the modulation depth increased; additionally, sounds with amplitude modulation had higher subjective loudness than those without amplitude modulation

  19. Numerical methods for stochastic partial differential equations with white noise

    CERN Document Server

    Zhang, Zhongqiang

    2017-01-01

    This book covers numerical methods for stochastic partial differential equations with white noise using the framework of Wong-Zakai approximation. The book begins with some motivational and background material in the introductory chapters and is divided into three parts. Part I covers numerical stochastic ordinary differential equations. Here the authors start with numerical methods for SDEs with delay using the Wong-Zakai approximation and finite difference in time. Part II covers temporal white noise. Here the authors consider SPDEs as PDEs driven by white noise, where discretization of white noise (Brownian motion) leads to PDEs with smooth noise, which can then be treated by numerical methods for PDEs. In this part, recursive algorithms based on Wiener chaos expansion and stochastic collocation methods are presented for linear stochastic advection-diffusion-reaction equations. In addition, stochastic Euler equations are exploited as an application of stochastic collocation methods, where a numerical compa...

  20. Aeroacoustics: Jet noise, combustion and core engine noise

    Science.gov (United States)

    Schwartz, I. R.

    1976-01-01

    The papers in this volume deal essentially with the question whether the amplification of noise is due to the jet noise phenomenon or perhaps an interaction of airframe and core engine noise. In the area of jet noise suppression, various promising suppressor concepts are examined. The swirling flow jet noise suppressor is shown to provide significant noise reduction with minimal thrust losses. Progress in the aircraft engine core noise problem is reflected by seven research-type papers. Two possible mechanisms are seen to be responsible for core noise. One is the direct noise radiated from the turbulent combustion in the primary combuster and transmitted through the turbine, passing out the nozzle into the far field. The other mechanism is the noise that is emitted from hot spots being convected through the turbine. Which of these mechanisms (or perhaps both mechanisms) is responsible for core noise, and what are the coupling mechanisms of core engine noise and jet noise are the questions confronting researchers.

  1. Neuroanatomical substrate of noise sensitivity

    DEFF Research Database (Denmark)

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

    2018-01-01

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

  2. 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.

  3. Noise Abatement Tradeoff Considerations

    Science.gov (United States)

    1981-05-01

    The intent of this study is to obtain information on small high-speed engines so that their effect on the urban environment may be assessed, and if necessary, programs devised to reduce the noise and other emissions from vehicles using these "highly ...

  4. 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 ? between the magnetization and the transport direction. The results are consistent

  5. 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...

  6. Wind turbine noise diagnostics

    International Nuclear Information System (INIS)

    Richarz, W.; Richarz, H.

    2009-01-01

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

  7. Expected Seismicity and the Seismic Noise Environment of Europa

    Science.gov (United States)

    Panning, Mark P.; Stähler, Simon C.; Huang, Hsin-Hua; Vance, Steven D.; Kedar, Sharon; Tsai, Victor C.; Pike, William T.; Lorenz, Ralph D.

    2018-01-01

    Seismic data will be a vital geophysical constraint on internal structure of Europa if we land instruments on the surface. Quantifying expected seismic activity on Europa both in terms of large, recognizable signals and ambient background noise is important for understanding dynamics of the moon, as well as interpretation of potential future data. Seismic energy sources will likely include cracking in the ice shell and turbulent motion in the oceans. We define a range of models of seismic activity in Europa's ice shell by assuming each model follows a Gutenberg-Richter relationship with varying parameters. A range of cumulative seismic moment release between 1016 and 1018 Nm/yr is defined by scaling tidal dissipation energy to tectonic events on the Earth's moon. Random catalogs are generated and used to create synthetic continuous noise records through numerical wave propagation in thermodynamically self-consistent models of the interior structure of Europa. Spectral characteristics of the noise are calculated by determining probabilistic power spectral densities of the synthetic records. While the range of seismicity models predicts noise levels that vary by 80 dB, we show that most noise estimates are below the self-noise floor of high-frequency geophones but may be recorded by more sensitive instruments. The largest expected signals exceed background noise by ˜50 dB. Noise records may allow for constraints on interior structure through autocorrelation. Models of seismic noise generated by pressure variations at the base of the ice shell due to turbulent motions in the subsurface ocean may also generate observable seismic noise.

  8. Mapping the gravitational wave background

    OpenAIRE

    Cornish, Neil J.

    2001-01-01

    The gravitational wave sky is expected to have isolated bright sources superimposed on a diffuse gravitational wave background. The background radiation has two components: a confusion limited background from unresolved astrophysical sources; and a cosmological component formed during the birth of the universe. A map of the gravitational wave background can be made by sweeping a gravitational wave detector across the sky. The detector output is a complicated convolution of the sky luminosity ...

  9. An analysis of ground and instrumental short-period noise

    Directory of Open Access Journals (Sweden)

    A. ROVELLI

    1978-06-01

    Full Text Available The main causes of background noise on seismic recordings are
    considered. For this purpose, numerical spectral analysis techniques are
    applied to records obtained from an analogue-digital converter.
    Firstly, the causes of noise due to the data acquisition system itself,
    particularly to the FM magnetic recording apparatus, are analysed.
    Subsequently, an analysis is made of seismic ground noise samples
    taken under various environmental conditions and recorded either in the
    field, or by telemetry, or on magnetic tape.

  10. JEM-X background models

    DEFF Research Database (Denmark)

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

    2003-01-01

    Background and determination of its components for the JEM-X X-ray telescope on INTEGRAL are discussed. A part of the first background observations by JEM-X are analysed and results are compared to predictions. The observations are based on extensive imaging of background near the Crab Nebula...

  11. Noise analysis of a low noise charge sensitive preamplifier

    International Nuclear Information System (INIS)

    Chen Bo; Liu Songqiu; Xue Zhihua; Zhao Jie

    2008-01-01

    On the basis of the traditional noise model, this paper makes a quantitative noise analysis of a self-made charge sensitive pre-amplifier and compares its result with that of Pspice simulation and practical measurements. Moreover, this paper figures out the practical formulas for the spectrum of output noise, the equivalent noise charge (ENC) and its slope respectively, thus facilitating the design and improvement of pre-amplifier. (authors)

  12. Combined Active Noise Control and noise reduction in Hearing Aids

    OpenAIRE

    Serizel, Romain; Moonen, Marc; Wouters, Jan; Jensen, Søren,

    2008-01-01

    International audience; This paper presents a combined active noise control and noise reduction scheme for hearing aids to tackle secondary path effects and effects of signal leakage through the fitting. While such leakage contributions and the secondary accoustic path from the reciever to the tympanic membrane are usually not taken into account in standard noise reduction systems, they appear to have a non-negligible impact on the final signal quality. Integrating an active noise control sys...

  13. Tandem Cylinder Noise Predictions

    Science.gov (United States)

    Lockard, 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

  14. 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)…

  15. 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 we...

  16. 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...

  17. Rating environmental noise on the basis of noise maps

    NARCIS (Netherlands)

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

    2006-01-01

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

  18. 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

  19. 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,

  20. 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 ...

  1. Fast High-Quality Noise

    DEFF Research Database (Denmark)

    Frisvad, Jeppe Revall; Wyvill, Geoff

    2007-01-01

    At the moment the noise functions available in a graphics programmer's toolbox are either slow to compute or they involve grid-line artifacts making them of lower quality. In this paper we present a real-time noise computation with no grid-line artifacts or other regularity problems. In other words......, we put a new tool in the box that computes fast high-quality noise. In addition to being free of artifacts, the noise we present does not rely on tabulated data (everything is computed on the fly) and it is easy to adjust quality vs. quantity for the noise. The noise is based on point rendering (like...... spot noise), but it extends to more than two dimensions. The fact that it is based on point rendering makes art direction of the noise much easier....

  2. Influence of music and music preference on acceptable noise levels in listeners with normal hearing.

    Science.gov (United States)

    Gordon-Hickey, Susan; Moore, Robert E

    2007-05-01

    Acceptable noise level (ANL) is defined as the maximum level of background noise that an individual is willing to accept while listening to speech. The type of background noise does not affect ANL results with the possible exception of music. The purpose of this study was to determine if ANL for music was different from ANL for twelve-talker babble and investigate if there was a correlation between ANL for music samples and preference for those music samples. Results demonstrated that ANL for music tended to be better than ANL for twelve-talker babble, indicating listeners were more willing to accept music as a background noise than speech babble. The results further demonstrated that ANL for the music samples were not correlated with preference for the music samples, indicating that ANL for music was not related to music preference. Therefore, music appeared to be processed differently as a background noise than twelve-talker babble.

  3. Leupeptin reduces impulse noise induced hearing loss

    Directory of Open Access Journals (Sweden)

    Gavriel Haim

    2011-12-01

    Full Text Available Abstract Background Exposure to continuous and impulse noise can induce a hearing loss. Leupeptin is an inhibitor of the calpains, a family of calcium-activated proteases which promote cell death. The objective of this study is to assess whether Leupeptin could reduce the hearing loss resulting from rifle impulse noise. Methods A polyethelene tube was implanted into middle ear cavities of eight fat sand rats (16 ears. Following determination of auditory nerve brainstem evoked response (ABR threshold in each ear, the animals were exposed to the noise of 10 M16 rifle shots. Immediately after the exposure, saline was then applied to one (control ear and non-toxic concentrations of leupeptin determined in the first phase of the study were applied to the other ear, for four consecutive days. Results Eight days after the exposure, the threshold shift (ABR in the control ears was significantly greater (44 dB than in the leupeptin ears (27 dB. Conclusion Leupeptin applied to the middle ear cavity can reduce the hearing loss resulting from exposure to impulse noise.

  4. BACKGROUNDER

    International Development Research Centre (IDRC) Digital Library (Canada)

    Corey Piccioni

    Saharan Africa at US$4 billion per year for grains alone (World Bank, 2010). Considerable scope exists for research to find effecve ways to reduce food losses while increasing returns through product quality control, market segmentaon,.

  5. Backgrounder

    International Development Research Centre (IDRC) Digital Library (Canada)

    IDRC CRDI

    Center for Mountain Ecosystem Studies, Kunming Institute of Botany of the Chinese Academy of Sciences, China: $1,526,000 to inform effective water governance in the Asian highlands of China, Nepal, and Pakistan. • Ashoka Trust for Research in Ecology and the Environment (ATREE), India: $1,499,300 for research on ...

  6. BACKGROUNDER

    International Development Research Centre (IDRC) Digital Library (Canada)

    IDRC CRDI

    particularly in urban areas and emerging hunger hotspots. Migration caused by the ... Deltas: Deltas in Africa and South Asia are some of the world's most vulnerable coastal areas because of a critical combination ... rise and land subsidence persist, 5.4 million people in Africa and Asia might be displaced by 2050:. 93% live.

  7. Backgrounder

    International Development Research Centre (IDRC) Digital Library (Canada)

    IDRC CRDI

    inequalities, and poverty based on rigorous data collection and analysis. ... at how poor urban planning may be contributing to forced evictions and mass relocations, which in turn can lead to violence in the form of ... communities with similar conditions of social exclusion experience different levels of violence. The study will.

  8. BACKGROUNDER

    International Development Research Centre (IDRC) Digital Library (Canada)

    IDRC CRDI

    Through this initiative, four consortia will conduct research in three “hot spots” – regions where demographic trends, socio-economic development pathways, and strong climate signals put large numbers of people and their livelihoods at risk: semi-arid regions, deltas, and Himalayan river basins. The initiative brings ...

  9. Subtraction-noise projection in gravitational-wave detector networks

    Science.gov (United States)

    Harms, Jan; Mahrdt, Christoph; Otto, Markus; Prieß, Malte

    2008-06-01

    In this paper, we present a successful implementation of a subtraction-noise projection method into a simple, simulated data analysis pipeline of a gravitational-wave search. We investigate the problem to reveal a weak stochastic background signal which is covered by a strong foreground of compact-binary coalescences. The foreground, which is estimated by matched filters, has to be subtracted from the data. Even an optimal analysis of foreground signals will leave subtraction noise due to estimation errors of template parameters which may corrupt the measurement of the background signal. The subtraction noise can be removed by a noise projection. We apply our analysis pipeline to the proposed future-generation space-borne Big Bang Observer mission which seeks for a stochastic background of primordial gravitational waves in the frequency range ˜0.1Hz—1Hz covered by a foreground of black-hole and neutron-star binaries. Our analysis is based on a simulation code which provides a dynamical model of a time-delay interferometer network. It generates the data as time series and incorporates the analysis pipeline together with the noise projection. Our results confirm previous ad hoc predictions which say that the Big Bang Observer will be sensitive to backgrounds with fractional energy densities below Ω=10-16.

  10. The Signal Importance of Noise

    Science.gov (United States)

    Macy, Michael; Tsvetkova, Milena

    2015-01-01

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

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

    International Nuclear Information System (INIS)

    Whitfield Aslund, Melissa L.; Ollson, Christopher A.; Knopper, Loren D.

    2013-01-01

    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

  12. A novel method for the evaluation of polarization and hemisphere coverage of HF radio noise measurement antennas

    NARCIS (Netherlands)

    Witvliet, Ben A.; van Maanen, Erik; Bentum, Marinus Jan; Slump, Cornelis H.; Schiphorst, Roelof

    2015-01-01

    In HF (3-30 MHz) communications the ambient electromagnetic background noise or 'radio noise' generally is the limiting factor in reception. Radio noise measurements are needed for spectrum pollution control and to provide reference levels for radio system design. This article discusses the

  13. White noise on bialgebras

    CERN Document Server

    Schürmann, Michael

    1993-01-01

    Stochastic processes with independent increments on a group are generalized to the concept of "white noise" on a Hopf algebra or bialgebra. The main purpose of the book is the characterization of these processes as solutions of quantum stochastic differential equations in the sense of R.L. Hudsonand K.R. Parthasarathy. The notes are a contribution to quantum probability but they are also related to classical probability, quantum groups, and operator algebras. The Az ma martingales appear as examples of white noise on a Hopf algebra which is a deformation of the Heisenberg group. The book will be of interest to probabilists and quantum probabilists. Specialists in algebraic structures who are curious about the role of their concepts in probablility theory as well as quantum theory may find the book interesting. The reader should havesome knowledge of functional analysis, operator algebras, and probability theory.

  14. 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.

  15. 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

  16. 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 ...

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

    Science.gov (United States)

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

    2014-01-01

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

  18. Tinnitus and leisure noise.

    Science.gov (United States)

    Williams, Warwick; Carter, Lyndal

    2017-04-01

    To study the relationship of life-time noise exposure and experience of tinnitus. Audiometric measures included otoscopy, pure tone air- and bone-conduction hearing threshold levels (HTL) and otoacoustic emissions (OAEs). Participants completed questionnaires including demographic information, past hearing health, history of participation in loud leisure activities, and attitudes to noise. A representative sample (1435) of the young (11-35 years old) Australian population. Of the sample, 63% indicated they experienced tinnitus in some form. There was no correlation of tinnitus experience with HTL or OAE amplitudes. Although median octave band HTLs for those who experienced tinnitus "all the time" were slightly higher for those who did not, neither group exhibited HTLs outside clinically-normal values. Of those who experienced tinnitus a direct correlation was found between frequency of experience of tinnitus and increasing cumulative, life-time noise exposure. Those who experienced tinnitus were more likely to report noticing deterioration in their hearing ability over time and to report difficulty hearing in quiet and/or noisy situations. Experience of tinnitus was found throughout this young population but not associated with HTLs or variation in OAE amplitudes. Males experienced 'permanent' tinnitus at significantly greater rate than females.

  19. Spectral differentiation of atmospheric fluorescent events from background Cerenkov emissions

    International Nuclear Information System (INIS)

    Bhat, C.L.; Sanecha, V.K.; Mitra, A.K.; Sapru, M.L.; Razdan, H.

    1985-01-01

    A pair of optical filters, one with transmission characteristics compatible with the atmospheric fluorescent bands and the other responding to longer wavelengths lying outside these bands, is shown to provide an efficent method for detecting fluorescent events in the presence of background Cerenkov emissions. The attendant reduction in the light of the sky at night provides the additional advantage of higher signal-to-noise ratio. (author)

  20. 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.

  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 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

  3. Stochastic gravitational wave background from the single-degenerate channel of type Ia supernovae

    International Nuclear Information System (INIS)

    Falta, David; Fisher, Robert

    2011-01-01

    We demonstrate that the integrated gravitational wave signal of type Ia supernovae (SNe Ia) in the single-degenerate channel out to cosmological distances gives rise to a continuous background to spaceborne gravitational wave detectors, including the Big Bang Observer and Deci-Hertz Interferometer Gravitational wave Observatory planned missions. This gravitational wave background from SNe Ia acts as a noise background in the frequency range 0.1-10 Hz, which heretofore was thought to be relatively free from astrophysical sources apart from neutron-star and white-dwarf binaries, and therefore a key window in which to study primordial gravitational waves generated by inflation. While inflationary energy scales of > or approx. 10 16 GeV yield inflationary gravitational wave backgrounds in excess of our range of predicted backgrounds, for lower energy scales of ∼10 15 GeV, the inflationary gravitational wave background becomes comparable to the noise background from SNe Ia.

  4. 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)

  5. Suppression background device in neutron detection by a scintillation detector

    International Nuclear Information System (INIS)

    Degtyarev, A.P.; Kozyr', Yu.E.; Prokopets, G.A.

    1980-01-01

    A pulse shape discriminator for suppression of cosmic and gamma background as well as for suppression of intrinsic noises of a photomultiplier is described. Identification of signals of background and neutrons is performed by means of comparison of relative intensity of fast and slow components of scintillator luminescence. Basic discriminator flowsheet which contains integrating and differential RC circuits and time-to-amplitude converter is given. The discriminator provides minimum energy of detected neutrons equal to 500 keV when using a FEhU-36 neutron detector with a stilbene crystal [ru

  6. Theory And Working Of Noise And Vibration

    International Nuclear Information System (INIS)

    Jeong, Il Rok

    1988-09-01

    This book deals with theory of noise including physical property of noise like term and characteristic of sound, occurrence of sound, characteristic of noise pollution and main cause of occurrence of noise, technique of prevention of noise with noise reduction, construction guide for prevention of noise, and measure of interior noise. It also has the theory of vibration such as an introduction of vibration, and technology of prevention of vibration, official test method of environmental pollution, and summary of protection of the environment.

  7. 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

  8. Road traffic noise: self-reported noise annoyance versus GIS modelled road traffic noise exposure.

    Science.gov (United States)

    Birk, Matthias; Ivina, Olga; von Klot, Stephanie; Babisch, Wolfgang; Heinrich, Joachim

    2011-11-01

    self-reported road traffic noise annoyance is commonly used in epidemiological studies for assessment of potential health effects. Alternatively, some studies have used geographic information system (GIS) modelled exposure to road traffic noise as an objective parameter. The aim of this study was to analyse the association between noise exposure due to neighbouring road traffic and the noise annoyance of adults, taking other determinants into consideration. parents of 951 Munich children from the two German birth cohorts GINIplus and LISAplus reported their annoyance due to road traffic noise at home. GIS modelled road traffic noise exposure (L(den), maximum within a 50 m buffer) from the noise map of the city of Munich was available for all families. GIS-based calculated distance to the closest major road (≥10,000 vehicles per day) and questionnaire based-information about family income, parental education and the type of the street of residence were explored for their potential influence. An ordered logit regression model was applied. The noise levels (L(den)) and the reported noise annoyance were compared with an established exposure-response function. the correlation between noise annoyance and noise exposure (L(den)) was fair (Spearman correlation r(s) = 0.37). The distance to a major road and the type of street were strong predictors for the noise annoyance. The annoyance modelled by the established exposure-response function and that estimated by the ordered logit model were moderately associated (Pearson's correlation r(p) = 0.50). road traffic noise annoyance was associated with GIS modelled neighbouring road traffic noise exposure (L(den)). The distance to a major road and the type of street were additional explanatory factors of the noise annoyance appraisal.

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

    International Nuclear Information System (INIS)

    1993-04-01

    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

  10. Why background colour matters to bees and flowers.

    Science.gov (United States)

    Bukovac, Zoë; Shrestha, Mani; Garcia, Jair E; Burd, Martin; Dorin, Alan; Dyer, Adrian G

    2017-05-01

    Flowers are often viewed by bee pollinators against a variety of different backgrounds. On the Australian continent, backgrounds are very diverse and include surface examples of all major geological stages of the Earth's history, which have been present during the entire evolutionary period of Angiosperms. Flower signals in Australia are also representative of typical worldwide evolutionary spectral adaptations that enable successful pollination. We measured the spectral properties of 581 natural surfaces, including rocks, sand, green leaves, and dry plant materials, sampled from tropical Cairns through to the southern tip of mainland Australia. We modelled in a hexagon colour space, how interactions between background spectra and flower-like colour stimuli affect reliable discrimination and detection in bee pollinators. We calculated the extent to which a given locus would be conflated with the loci of a different flower-colour stimulus using empirically determined colour discrimination regions for bee vision. Our results reveal that whilst colour signals are robust in homogeneous background viewing conditions, there could be significant pressure on plant flowers to evolve saliently-different colours to overcome background spectral noise. We thus show that perceptual noise has a large influence on how colour information can be used in natural conditions.

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

    International Nuclear Information System (INIS)

    Ormel, F.T.; Eecen, P.J.; Herman, S.A.

    2003-10-01

    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

  12. 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 ...

  13. Speaking up: Killer whales (Orcinus orca) increase their call amplitude in response to vessel noise.

    Science.gov (United States)

    Holt, Marla M; Noren, Dawn P; Veirs, Val; Emmons, Candice K; Veirs, Scott

    2009-01-01

    This study investigated the effects of anthropogenic sound exposure on the vocal behavior of free-ranging killer whales. Endangered Southern Resident killer whales inhabit areas including the urban coastal waters of Puget Sound near Seattle, WA, where anthropogenic sounds are ubiquitous, particularly those from motorized vessels. A calibrated recording system was used to measure killer whale call source levels and background noise levels (1-40 kHz). Results show that whales increased their call amplitude by 1 dB for every 1 dB increase in background noise levels. Furthermore, nearby vessel counts were positively correlated with these observed background noise levels.

  14. 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

  15. Emergency department noise: mental activation or mental stress?

    Science.gov (United States)

    Folscher, Lindy-Lee; Goldstein, Lara Nicole; Wells, Mike; Rees, David

    2015-06-01

    Healthcare professionals working in emergency medicine are often exposed to noisy environments. We determined if there is any difference in cognitive task performance required for clinical decision-making of healthcare professionals in a quiet compared with noisy environment and to assess the subjective experience of participants with regard to performance in a noisy environment. This was a prospective cross-over study conducted at three academic hospitals in Johannesburg, South Africa. 41 doctors involved in the emergency management of patients were administered six matched and prevalidated medical questions over a 30-min period. Each doctor completed half of the questions with exposure to ambient noise (range 40-52 dB(A)) and the other half with exposure to pre-recorded background emergency department noise at 80-85 dB(A). The questions were completed in alternating quiet and noise: half of the physicians answered the odd questions in noise and half answered even numbered questions in noise. Each question was scored out of 10 and the time taken to complete each question was recorded. Overall median test scores in quiet and noise were 18.5/30 and 20/30 (p=0.2), respectively; time for test completion was longer in quiet (836 s in quiet and 819 s in noise (p=0.006)). While there was no statistically significant difference in task performance, 65% of the doctors found the noise distracting with 88% experiencing varying degrees of stress. Performance of mental tasks is maintained during noise exposure but noise exposure is associated with significant degrees of self-reported distress. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  16. 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

  17. Accuracy of cochlear implant recipients in speech reception in the presence of background music.

    Science.gov (United States)

    Gfeller, Kate; Turner, Christopher; Oleson, Jacob; Kliethermes, Stephanie; Driscoll, Virginia

    2012-12-01

    This study examined speech recognition abilities of cochlear implant (CI) recipients in the spectrally complex listening condition of 3 contrasting types of background music, and compared performance based upon listener groups: CI recipients using conventional long-electrode devices, Hybrid CI recipients (acoustic plus electric stimulation), and normal-hearing adults. We tested 154 long-electrode CI recipients using varied devices and strategies, 21 Hybrid CI recipients, and 49 normal-hearing adults on closed-set recognition of spondees presented in 3 contrasting forms of background music (piano solo, large symphony orchestra, vocal solo with small combo accompaniment) in an adaptive test. Signal-to-noise ratio thresholds for speech in music were examined in relation to measures of speech recognition in background noise and multitalker babble, pitch perception, and music experience. The signal-to-noise ratio thresholds for speech in music varied as a function of category of background music, group membership (long-electrode, Hybrid, normal-hearing), and age. The thresholds for speech in background music were significantly correlated with measures of pitch perception and thresholds for speech in background noise; auditory status was an important predictor. Evidence suggests that speech reception thresholds in background music change as a function of listener age (with more advanced age being detrimental), structural characteristics of different types of music, and hearing status (residual hearing). These findings have implications for everyday listening conditions such as communicating in social or commercial situations in which there is background music.

  18. Aluminum as a source of background in low background experiments

    Energy Technology Data Exchange (ETDEWEB)

    Majorovits, B., E-mail: bela@mppmu.mpg.de [MPI fuer Physik, Foehringer Ring 6, 80805 Munich (Germany); Abt, I. [MPI fuer Physik, Foehringer Ring 6, 80805 Munich (Germany); Laubenstein, M. [Laboratori Nazionali del Gran Sasso, INFN, S.S.17/bis, km 18 plus 910, I-67100 Assergi (Italy); Volynets, O. [MPI fuer Physik, Foehringer Ring 6, 80805 Munich (Germany)

    2011-08-11

    Neutrinoless double beta decay would be a key to understanding the nature of neutrino masses. The next generation of High Purity Germanium experiments will have to be operated with a background rate of better than 10{sup -5} counts/(kg y keV) in the region of interest around the Q-value of the decay. Therefore, so far irrelevant sources of background have to be considered. The metalization of the surface of germanium detectors is in general done with aluminum. The background from the decays of {sup 22}Na, {sup 26}Al, {sup 226}Ra and {sup 228}Th introduced by this metalization is discussed. It is shown that only a special selection of aluminum can keep these background contributions acceptable.

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

    Energy Technology Data Exchange (ETDEWEB)

    Talukdar, D.; Bose, Suvendu; Bardhan, K. K. [Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064 (India); Chakraborty, R. K. [Bidhannagar College, EB - 2, Bidhannagar, Kolkata 700064 (India)

    2011-01-15

    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 {mu}A 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.

  20. Cortical encoding of speech acoustics: Effects of noise and amplification.

    Science.gov (United States)

    Kuruvilla-Mathew, Abin; Purdy, Suzanne C; Welch, David

    2015-01-01

    To investigate speech stimuli and background-noise-dependent changes in cortical auditory-evoked potentials (CAEPs) in unaided and aided conditions, and determine amplification effects on CAEPs. CAEPs to naturally produced syllables in quiet and in multi-talker babble were recorded, with and without a hearing aid in the right ear. At least 300 artifact-free trials for each participant were required to measure latencies and amplitudes of CAEPs. Acoustic characteristics of the hearing-aid-transduced stimuli were measured using in-the-canal probe microphone measurements to determine unaided versus aided SNR and to compare stimulus acoustic characteristics to CAEP findings. Ten participants with normal hearing, aged 19 to 35 years. CAEP latencies and amplitudes showed significant effects of speech contrast, background noise, and amplification. N1 and P2 components varied differently across conditions. In general, cortical processing in noise was influenced by SNR and the spectrum of the speech stimuli. Hearing-aid-induced spectral and temporal changes to the speech stimuli affected P1-N1-P2 components. Amplification produced complex effects on latencies and amplitudes across speech stimuli and CAEP components, and for quiet versus noise conditions. CAEP components reflect spectral and temporal characteristics of speech stimuli and acoustic changes induced by background noise and amplification.

  1. 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

  2. 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

  3. Contribution to the G0 violation of parity experience: calculation and simulation of radiative corrections and the background noise study; Contribution a l'experience G0 de violation de la parite : calcul et simulation des corrections radiatives et etude du bruit de fond

    Energy Technology Data Exchange (ETDEWEB)

    Guler, Hayg [Univ. of Paris, Orsay (France)

    2003-12-17

    In the framework of quantum chromodynamics, the nucleon is made of three valence quarks surrpounded 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 Go we using 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 Go spectrometer. A complete calculation of radiative corrections has been clone 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.

  4. 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)

  5. 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.

  6. Noise Estimation and Quality Assessment of Gaussian Noise Corrupted Images

    Science.gov (United States)

    Kamble, V. M.; Bhurchandi, K.

    2018-03-01

    Evaluating the exact quantity of noise present in an image and quality of an image in the absence of reference image is a challenging task. We propose a near perfect noise estimation method and a no reference image quality assessment method for images corrupted by Gaussian noise. The proposed methods obtain initial estimate of noise standard deviation present in an image using the median of wavelet transform coefficients and then obtains a near to exact estimate using curve fitting. The proposed noise estimation method provides the estimate of noise within average error of +/-4%. For quality assessment, this noise estimate is mapped to fit the Differential Mean Opinion Score (DMOS) using a nonlinear function. The proposed methods require minimum training and yields the noise estimate and image quality score. Images from Laboratory for image and Video Processing (LIVE) database and Computational Perception and Image Quality (CSIQ) database are used for validation of the proposed quality assessment method. Experimental results show that the performance of proposed quality assessment method is at par with the existing no reference image quality assessment metric for Gaussian noise corrupted images.

  7. 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...

  8. Updating working memory in aircraft noise and speech 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...

  9. The Cosmic Infrared Background Experiment

    OpenAIRE

    Bock, James; Battle, John; Cooray, Asantha; Kawada, Mitsunobu; Keating, Brian; Lange, Andrew; Lee, Dae-Hea; Matsumoto, Toshio; Matsuura, Shuji; Pak, Soojong; Renbarger, Tom; Sullivan, Ian; Tsumura, Kohji; Wada, Takehiko; Watabe, Toyoki

    2005-01-01

    We are developing a rocket-borne instrument (the Cosmic Infrared Background ExpeRiment, or CIBER) to search for signatures of primordial galaxy formation in the cosmic near-infrared extra-galactic background. CIBER consists of a wide-field two-color camera, a low-resolution absolute spectrometer, and a high-resolution narrow-band imaging spectrometer. The cameras will search for spatial fluctuations in the background on angular scales from 7 arcseconds to 2 degrees over a range of angular sca...

  10. Noise storm coordinated observations

    International Nuclear Information System (INIS)

    Elgaroey, Oe.; Tlamicha, A.

    1983-01-01

    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

  11. Gamma noise in CCDs

    International Nuclear Information System (INIS)

    Autio, G.W.; Bafico, M.A.

    1975-01-01

    The overall results indicated that charge coupled devices (CCD) used to read out detector signals or as signal processing electronics in future space sensors can operate real time in a high ionising radiation environment. Future work should be directed towards hardening the CCDs during the fabrication processes in order that they may survive total radiation doses up to 1 x 10 6 Rad (Si) and toward investigating ionising radiation effects in CCDs that are coupled with i.r. detectors. CCD devices employed to read out detector signals can be made capable of handling radiation induced excess noise and high false alarm rates generated in the detector elements. Ionising radiation effects induced in the detectors are expected to dominate those generated directly in the CCD readout structure; how much depends on the relative size of the detector. The low frequency γ induced excess noise measured in the CCD/MOSFET structure could cause problems for space sensors required to operate in real time only at the very high γ flux levels. Discrimination and circumvention techniques at the CCD ERO output are possible. γ pulses measured at the CCD ERO output were distributed in amplitude and exhibited variable pulse widths (some were many times a clock period). (author)

  12. 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.

  13. Single-electron thermal noise.

    Science.gov (United States)

    Nishiguchi, Katsuhiko; Ono, Yukinori; Fujiwara, Akira

    2014-07-11

    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.

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

    OpenAIRE

    Bianchi, C.; Meloni, A.

    2007-01-01

    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 descri...

  15. Berkeley Low Background Counting Facility

    Data.gov (United States)

    Federal Laboratory Consortium — Sensitive low background assay detectors and sample analysis are available for non-destructive direct gamma-ray assay of samples. Neutron activation analysis is also...

  16. Botanical Dietary Supplements: Background Information

    Science.gov (United States)

    ... Office of Dietary Supplements Health Professional Other Resources Botanical Dietary Supplements Background Information Have a question? Ask ... on botanical dietary supplements? Disclaimer What is a botanical? A botanical is a plant or plant part ...

  17. WHO Environmental Noise Guidelines for the European Region: A Systematic Review on Environmental Noise and Adverse Birth Outcomes

    Directory of Open Access Journals (Sweden)

    Mark J. Nieuwenhuijsen

    2017-10-01

    studies, we did not conduct meta-analyses. Discussion: This systematic review is supported by previous systematic reviews and meta-analyses that suggested that there may be some suggestive evidence for an association between environmental noise exposure and birth outcomes, although they pointed more generally to a stronger role of occupational noise exposure, which tends to be higher and last longer. Very strict criteria for inclusion and exclusion of studies, performance of quality assessment for risk of bias, and finally applying GRADE principles for judgment of quality of evidence are the strengths of this review. Conclusions: We found evidence of very low quality for associations between aircraft noise and preterm birth, low birth weight and congenital anomalies, and low quality evidence for an association between road traffic noise and low birth weight, preterm birth and small for gestational age. Further high quality studies are required to establish such associations. Future studies are recommended to apply robust exposure assessment methods (e.g., modeled or measured noise levels at bedroom façade, disentangle associations for different sources of noise as well as daytime and nighttime noise, evaluate the impacts of noise evens (that stand out of the noise background, and control the analyses for confounding factors, such as socioeconomic status, lifestyle factors and other environmental factors, especially air pollution.

  18. WHO Environmental Noise Guidelines for the European Region: A Systematic Review on Environmental Noise and Adverse Birth Outcomes.

    Science.gov (United States)

    Nieuwenhuijsen, Mark J; Ristovska, Gordana; Dadvand, Payam

    2017-10-19

    not conduct meta-analyses. Discussion: This systematic review is supported by previous systematic reviews and meta-analyses that suggested that there may be some suggestive evidence for an association between environmental noise exposure and birth outcomes, although they pointed more generally to a stronger role of occupational noise exposure, which tends to be higher and last longer. Very strict criteria for inclusion and exclusion of studies, performance of quality assessment for risk of bias, and finally applying GRADE principles for judgment of quality of evidence are the strengths of this review. We found evidence of very low quality for associations between aircraft noise and preterm birth, low birth weight and congenital anomalies, and low quality evidence for an association between road traffic noise and low birth weight, preterm birth and small for gestational age. Further high quality studies are required to establish such associations. Future studies are recommended to apply robust exposure assessment methods (e.g., modeled or measured noise levels at bedroom façade), disentangle associations for different sources of noise as well as daytime and nighttime noise, evaluate the impacts of noise evens (that stand out of the noise background), and control the analyses for confounding factors, such as socioeconomic status, lifestyle factors and other environmental factors, especially air pollution.

  19. An efficient feedback active noise control algorithm based on reduced-order linear predictive modeling of FMRI acoustic noise.

    Science.gov (United States)

    Kannan, Govind; Milani, Ali A; Panahi, Issa M S; Briggs, Richard W

    2011-12-01

    Functional magnetic resonance imaging (fMRI) acoustic noise exhibits an almost periodic nature (quasi-periodicity) due to the repetitive nature of currents in the gradient coils. Small changes occur in the waveform in consecutive periods due to the background noise and slow drifts in the electroacoustic transfer functions that map the gradient coil waveforms to the measured acoustic waveforms. The period depends on the number of slices per second, when echo planar imaging (EPI) sequencing is used. Linear predictability of fMRI acoustic noise has a direct effect on the performance of active noise control (ANC) systems targeted to cancel the acoustic noise. It is shown that by incorporating some samples from the previous period, very high linear prediction accuracy can be reached with a very low order predictor. This has direct implications on feedback ANC systems since their performance is governed by the predictability of the acoustic noise to be cancelled. The low complexity linear prediction of fMRI acoustic noise developed in this paper is used to derive an effective and low-cost feedback ANC system.

  20. Noise disturbance in open-plan study environments: a field study on noise sources, student tasks and room acoustic parameters.

    Science.gov (United States)

    Braat-Eggen, P Ella; van Heijst, Anne; Hornikx, Maarten; Kohlrausch, Armin

    2017-09-01

    The aim of this study is to gain more insight in the assessment of noise in open-plan study environments and to reveal correlations between noise disturbance experienced by students and the noise sources they perceive, the tasks they perform and the acoustic parameters of the open-plan study environment they work in. Data were collected in five open-plan study environments at universities in the Netherlands. A questionnaire was used to investigate student tasks, perceived sound sources and their perceived disturbance, and sound measurements were performed to determine the room acoustic parameters. This study shows that 38% of the surveyed students are disturbed by background noise in an open-plan study environment. Students are mostly disturbed by speech when performing complex cognitive tasks like studying for an exam, reading and writing. Significant but weak correlations were found between the room acoustic parameters and noise disturbance of students. Practitioner Summary: A field study was conducted to gain more insight in the assessment of noise in open-plan study environments at universities in the Netherlands. More than one third of the students was disturbed by noise. An interaction effect was found for task type, source type and room acoustic parameters.

  1. 34. Meeting of Experts. Noise immission

    International Nuclear Information System (INIS)

    2001-01-01

    In quiet areas there is a risk that wind turbine noise will exceed the background level even if it is lower than the immission limit. It will however be quite unpractical to take special notice to such areas and since the immission limit is respected the noise level will still be acceptable. Complaints from neighbours can unfortunately be expected no matter where the wind power plants are built. A small study in Denmark shows that about 10% of the population will feel disturbed by the immission limits that they have. Some of the participants pointed out that it would be simpler if wind power noise was included in other noise immission regulations. Within the European Union the Commission has made a proposal for common noise immission level descriptions and evaluation methods. It is primarily intended for traffic noise but can be expanded to include other areas, such as wind power noise. It suggests an equivalent annual average sound level (Lden) where the night level has a penalty of 10 dB(A) and the evening level of 5 dB(A). It should be emphasised that the proposal is not concerned with the specific values of the noise level limits, only with how they are defined. In some countries the limit varies with the time of the day. The night limit is the lowest and therefore the determining value in most cases. Wind turbines with variable RPM can however alter their speed to fit the limits and hence increase the energy output during the day and lower it at night. The result will be that a turbine with variable RPM can produce more energy than a similar one with fixed RPM but still fulfil the noise regulations. Though there are not many of these wind turbines installed today the number is likely to increase in the near future. As said when different day and night limits were discussed, having different immission limits at different hours will increase the possible energy output of a wind power plant with variable RPM. The new regulation in Holland uses a wind speed

  2. Cosmic microwave background, where next?

    CERN Multimedia

    CERN. Geneva

    2009-01-01

    Ground-based, balloon-borne and space-based experiments will observe the Cosmic Microwave Background in greater details to address open questions about the origin and the evolution of the Universe. In particular, detailed observations the polarization pattern of the Cosmic Microwave Background radiation have the potential to directly probe physics at the GUT scale and illuminate aspects of the physics of the very early Universe.

  3. Estimating COCOM Natural Background Dormancy

    Science.gov (United States)

    2015-04-01

    ER D C/ CR RE L TR -1 5- 7 Phase IV Army Camouflage Development Effort Estimating COCOM Natural Background Dormancy Co ld R eg io ns...ERDC/CRREL TR-15-7 April 2015 Estimating COCOM Natural Background Dormancy Alexis L. Coplin and Charles C. Ryerson Cold Regions Research and...phenological stage, controls color and tex- ture of natural vegetation as it cycles through greenup, verdancy, senes- cence, and dormancy . For the Army

  4. Improvement of LOD in Fluorescence Detection with Spectrally Nonuniform Background by Optimization of Emission Filtering.

    Science.gov (United States)

    Galievsky, Victor A; Stasheuski, Alexander S; Krylov, Sergey N

    2017-10-17

    The limit-of-detection (LOD) in analytical instruments with fluorescence detection can be improved by reducing noise of optical background. Efficiently reducing optical background noise in systems with spectrally nonuniform background requires complex optimization of an emission filter-the main element of spectral filtration. Here, we introduce a filter-optimization method, which utilizes an expression for the signal-to-noise ratio (SNR) as a function of (i) all noise components (dark, shot, and flicker), (ii) emission spectrum of the analyte, (iii) emission spectrum of the optical background, and (iv) transmittance spectrum of the emission filter. In essence, the noise components and the emission spectra are determined experimentally and substituted into the expression. This leaves a single variable-the transmittance spectrum of the filter-which is optimized numerically by maximizing SNR. Maximizing SNR provides an accurate way of filter optimization, while a previously used approach based on maximizing a signal-to-background ratio (SBR) is the approximation that can lead to much poorer LOD specifically in detection of fluorescently labeled biomolecules. The proposed filter-optimization method will be an indispensable tool for developing new and improving existing fluorescence-detection systems aiming at ultimately low LOD.

  5. Determination of signal intensity affected by Gaussian noise

    International Nuclear Information System (INIS)

    Blostein, Jeronimo J.; Bennun, Leonardo

    1999-01-01

    A methodology based on maximum likelihood criteria, to identify and quantify an arbitrary signal affected by Gaussian noise is shown. To use this methodology it is necessary to know the position in the spectrum where the signal of interest should appear, and the shape of the signal when the background is null or unappreciable. (author)

  6. Integrated Spacesuit Audio System Enhances Speech Quality and Reduces Noise

    Science.gov (United States)

    Huang, Yiteng Arden; Chen, Jingdong; Chen, Shaoyan Sharyl

    2009-01-01

    A new approach has been proposed for increasing astronaut comfort and speech capture. Currently, the special design of a spacesuit forms an extreme acoustic environment making it difficult to capture clear speech without compromising comfort. The proposed Integrated Spacesuit Audio (ISA) system is to incorporate the microphones into the helmet and use software to extract voice signals from background noise.

  7. Prevalence of noise induced hearing loss among employees at a ...

    African Journals Online (AJOL)

    Background: Noise induced hearing loss (NIHL) is within the top five occupational illnesses in Zimbabwe. Workers at a mining company complained about loss of hearing at the mine clinic. Objective: To determine the prevalence of NIHL among employees at the Mine. Methods: We conducted a descriptive cross sectional ...

  8. Modelling traffic noise level on roadside traders at Wurukum market ...

    African Journals Online (AJOL)

    The model indicates high level of ambient noise which was attributed to intensive market activities from the background. The model was checked using Chi square test at 5% level of significance and coefficient of determin ation (R 2 =0.7216) which gave satisfactory results. A strategy of relocation and splitting the market ...

  9. Relationship between Speech Intelligibility and Speech Comprehension in Babble Noise

    Science.gov (United States)

    Fontan, Lionel; Tardieu, Julien; Gaillard, Pascal; Woisard, Virginie; Ruiz, Robert

    2015-01-01

    Purpose: The authors investigated the relationship between the intelligibility and comprehension of speech presented in babble noise. Method: Forty participants listened to French imperative sentences (commands for moving objects) in a multitalker babble background for which intensity was experimentally controlled. Participants were instructed to…

  10. Audio-Visual Speech in Noise Perception in Dyslexia

    Science.gov (United States)

    van Laarhoven, Thijs; Keetels, Mirjam; Schakel, Lemmy; Vroomen, Jean

    2018-01-01

    Individuals with developmental dyslexia (DD) may experience, besides reading problems, other speech-related processing deficits. Here, we examined the influence of visual articulatory information (lip-read speech) at various levels of background noise on auditory word recognition in children and adults with DD. We found that children with a…

  11. Pregnancy and childhood exposure to residential traffic noise and overweight at 7 years of age

    DEFF Research Database (Denmark)

    Christensen, Jeppe Schultz; Hjortebjerg, Dorrit; Raaschou-Nielsen, Ole

    2016-01-01

    Background: Exposure to road traffic noise has been associated with adiposity and diabetes in adults. The suggested pathways have been through sleep disturbance and stress. Children may be particularly susceptible to noise induced sleep disturbance and stress and the effects hereof. Objectives...

  12. Residential traffic noise exposure and vestibular schwannoma - a Danish case-control study

    DEFF Research Database (Denmark)

    Roswall, Nina; Stangerup, Sven-Eric; Cayé-Thomasen, Per

    2017-01-01

    BACKGROUND: Few risk factors for sporadic vestibular schwannoma (VS) are known. Several studies have proposed an increased risk with occupational noise exposure, whereas no studies have investigated residential traffic noise exposure as a risk factor. The present study investigated if residential...

  13. 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

    in STI-values including the human activity noise compared to STI-values including only technical background noise as the standard recommends. Furthermore, at 500 Hz a regression analysis showed that the density of people in an room, absorption area, reverberation time as well as the ISO 3382-3 parameter...

  14. Long-Term Exposure to Road Traffic Noise and Nitrogen Dioxide and Risk of Heart Failure

    DEFF Research Database (Denmark)

    Sørensen, Mette; Wendelboe Nielsen, Olav; Sajadieh, Ahmad

    2017-01-01

    BACKGROUND: Although air pollution and road traffic noise have been associated with higher risk of cardiovascular diseases, associations with heart failure have received only little attention. OBJECTIVES: We aimed to investigate whether long-term exposure to road traffic noise and nitrogen dioxid...

  15. Emission noise spectrum in a premixed H2-O2-N2 flame

    NARCIS (Netherlands)

    Alkemade, C.T.J.; Hooymayers, H.P.; Lijnse, P.L.; Vierbergen, T.J.M.J.

    Experimental noise spectra in the frequency range of 15–105 Hz are reported for the thermal emission of the first resonance doublet of Na and K in a premixed H2-O2-N2 flame, and for the flame background emission. Under certain conditions, low-frequency peaks arise in the noise spectrum below 100 Hz,

  16. Impact of Noise and Working Memory on Speech Processing in Adults with and without ADHD

    Science.gov (United States)

    Michalek, Anne M. P.

    2012-01-01

    Auditory processing of speech is influenced by internal (i.e., attention, working memory) and external factors (i.e., background noise, visual information). This study examined the interplay among these factors in individuals with and without ADHD. All participants completed a listening in noise task, two working memory capacity tasks, and two…

  17. Children's Perception of Conversational and Clear American-English Vowels in Noise

    Science.gov (United States)

    Leone, Dorothy; Levy, Erika S.

    2015-01-01

    Purpose: Much of a child's day is spent listening to speech in the presence of background noise. Although accurate vowel perception is important for listeners' accurate speech perception and comprehension, little is known about children's vowel perception in noise. "Clear speech" is a speech style frequently used by talkers in the…

  18. Noise.Induced Hearing Loss Still a Problem in Shipbuilders: A Cross ...

    African Journals Online (AJOL)

    Background: Workplace safety regulations seek to mitigate noise.induced hearing loss (NIHL), conventionally associated with the shipbuilding industry. Despite this, are workers still predisposed to NIHL? Aims: To study the prevalence of NIHL among noise.exposed subjects in the shipbuilding industry in Goa and to ...

  19. High level white noise generator

    International Nuclear Information System (INIS)

    Borkowski, C.J.; Blalock, T.V.

    1979-01-01

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

  20. Noise-induced hearing loss

    Energy Technology Data Exchange (ETDEWEB)

    Catlin, F.I.

    1986-03-01

    Hearing loss affects 30 million people in the United States; of these, 21 million are over the age of 65 years. This disorder may have several causes: heredity, noise, aging, and disease. Hearing loss from noise has been recognized for centuries but was generally ignored until some time after the Industrial Revolution. Hearing loss from occupational exposure to hazardous noise was identified as a compensable disability by the United States courts in 1948 to 1959. Development of noisy jet engines and supersonic aircraft created additional claims for personal and property damage in the 1950s and 1960s. These conditions led to legislation for noise control in the form of the Occupational Safety and Health Act of 1970 and the Noise Control Act of 1972. Protection of the noise-exposed employee was also an objective of the Hearing Conservation Act of 1971. Subsequent studies have confirmed the benefits of periodic hearing tests for workers exposed to hazardous noise and of otologic evaluation as part of the hearing conservation process. Research studies in laboratory animals, using scanning electron microscopical techniques, have demonstrated that damage to the inner ear and organ of hearing can occur even though subjective (conditioned) response to sound stimuli remains unaffected. Some investigators have employed an epidemiologic approach to identify risk factors and to develop profiles to susceptibility to noise-induced hearing loss. The need for joint involvement of workers and employers in the reduction and control of occupational noise hazards is evident. 19 references.

  1. High level white noise generator

    Science.gov (United States)

    Borkowski, Casimer J.; Blalock, Theron V.

    1979-01-01

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

  2. 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.

  3. Evaluation of speech transmission in open public spaces affected by combined noises.

    Science.gov (United States)

    Lee, Pyoung Jik; Jeon, Jin Yong

    2011-07-01

    In the present study, the effects of interference from combined noises on speech transmission were investigated in a simulated open public space. Sound fields for dominant noises were predicted using a typical urban square model surrounded by buildings. Then road traffic noise and two types of construction noises, corresponding to stationary and impulsive noises, were selected as background noises. Listening tests were performed on a group of adults, and the quality of speech transmission was evaluated using listening difficulty as well as intelligibility scores. During the listening tests, two factors that affect speech transmission performance were considered: (1) temporal characteristics of construction noise (stationary or impulsive) and (2) the levels of the construction and road traffic noises. The results indicated that word intelligibility scores and listening difficulty ratings were affected by the temporal characteristics of construction noise due to fluctuations in the background noise level. It was also observed that listening difficulty is unable to describe the speech transmission in noisy open public spaces showing larger variation than did word intelligibility scores. © 2011 Acoustical Society of America

  4. Microwave SQUID multiplexer demonstration for cosmic microwave background imagers

    Science.gov (United States)

    Dober, B.; Becker, D. T.; Bennett, D. A.; Bryan, S. A.; Duff, S. M.; Gard, J. D.; Hays-Wehle, J. P.; Hilton, G. C.; Hubmayr, J.; Mates, J. A. B.; Reintsema, C. D.; Vale, L. R.; Ullom, J. N.

    2017-12-01

    Key performance characteristics are demonstrated for the microwave superconducting quantum interference device (SQUID) multiplexer (μmux) coupled to transition edge sensor (TES) bolometers that have been optimized for cosmic microwave background (CMB) observations. In a 64-channel demonstration, we show that the μmux produces a white, input referred current noise level of 29 pA/ √{H z } at a microwave probe tone power of -77 dB, which is well below the expected fundamental detector and photon noise sources for a ground-based CMB-optimized bolometer. Operated with negligible photon loading, we measure 98 pA/ √{H z } in the TES-coupled channels biased at 65% of the sensor normal resistance. This noise level is consistent with that predicted from bolometer thermal fluctuation (i.e., phonon) noise. Furthermore, the power spectral density is white over a range of frequencies down to ˜100 mHz, which enables CMB mapping on large angular scales that constrain the physics of inflation. Additionally, we report cross-talk measurements that indicate a level below 0.3%, which is less than the level of cross-talk from multiplexed readout systems in deployed CMB imagers. These measurements demonstrate the μmux as a viable readout technique for future CMB imaging instruments.

  5. Physiological, Psychological, and Social Effects of Noise

    Science.gov (United States)

    Kryter, K. D.

    1984-01-01

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

  6. Music listening while you learn: No influence of background music on verbal learning

    OpenAIRE

    J?ncke, Lutz; Sandmann, Pascale

    2010-01-01

    Abstract Background Whether listening to background music enhances verbal learning performance is still disputed. In this study we investigated the influence of listening to background music on verbal learning performance and the associated brain activations. Methods Musical excerpts were composed for this study to ensure that they were unknown to the subjects and designed to vary in tempo (fast vs. slow) and consonance (in-tune vs. out-of-tune). Noise was used as control stimulus. 75 subject...

  7. Passerine birds breeding under chronic noise experience reduced fitness.

    Directory of Open Access Journals (Sweden)

    Julia Schroeder

    Full Text Available BACKGROUND: Fitness in birds has been shown to be negatively associated with anthropogenic noise, but the underlying mechanisms remain obscure. It is however crucial to understand the mechanisms of how urban noise impinges on fitness to obtain a better understanding of the role of chronic noise in urban ecology. Here, we examine three hypotheses on how noise might reduce reproductive output in passerine birds: (H1 by impairing mate choice, (H2 by reducing territory quality and (H3 by impeding chick development. METHODOLOGY/PRINCIPAL FINDINGS: We used long-term data from an island population of house sparrows, Passer domesticus, in which we can precisely estimate fitness. We found that nests in an area affected by the noise from large generators produced fewer young, of lower body mass, and fewer recruits, even when we corrected statistically for parental genetic quality using a cross-fostering set-up, supporting H3. Also, individual females provided their young with food less often when they bred in the noisy area compared to breeding attempts by the same females elsewhere. Furthermore, we show that females reacted flexibly to increased noise levels by adjusting their provisioning rate in the short term, which suggests that noise may be a causal factor that reduces reproductive output. We rejected H1 and H2 because nestbox occupancy, parental body mass, age and reproductive investment did not differ significantly between noisy and quiet areas. CONCLUSIONS/SIGNIFICANCE: OUR RESULTS SUGGEST A PREVIOUSLY UNDESCRIBED MECHANISM TO EXPLAIN HOW ENVIRONMENTAL NOISE CAN REDUCE FITNESS IN PASSERINE BIRDS: by acoustically masking parent-offspring communication. More importantly, using a cross-fostering set-up, our results demonstrate that birds breeding in a noisy environment experience significant fitness costs. Chronic noise is omnipresent around human habitation and may produces similar fitness consequences in a wide range of urban bird species.

  8. Wideband Low Noise Amplifiers Exploiting Thermal Noise Cancellation

    NARCIS (Netherlands)

    Bruccoleri, F.; Klumperink, Eric A.M.; Nauta, Bram

    2005-01-01

    Low Noise Amplifiers (LNAs) are commonly used to amplify signals that are too weak for direct processing for example in radio or cable receivers. Traditionally, low noise amplifiers are implemented via tuned amplifiers, exploiting inductors and capacitors in resonating LC-circuits. This can render

  9. Combined effect of smoking and occupational exposure to noise on hearing loss in steel factory workers

    OpenAIRE

    Mizoue, T; Miyamoto, T; Shimizu, T

    2003-01-01

    Background: Evidence has accumulated concerning the adverse effects of smoking on hearing acuity, but it is not clear whether smoking modifies the association between exposure to noise and hearing loss.

  10. Croatian Experience in Road Traffic Noise Management - Concrete Noise Barriers

    Directory of Open Access Journals (Sweden)

    Ahac Saša

    2014-07-01

    Full Text Available The paper gives an overview of concrete noise barrier application in several EU countries and in Croatia. It describes a process of introducing different noise protection solutions on Croatian market in the phase of intensive motorway construction in recent years. Namely, an extensive motorway network has been constructed in Croatia in the last 10 years. Following the process of motorway construction, noise protection walls have also been erected. Usage of different building materials and installation processes as well as variations in building expenditures has led to a comparative analysis of several types of noise protection solutions (expanded clay, wood fibre including a new eco-innovative product RUCONBAR, which incorporates rubber granules from recycled waste tyres to form a porous noise absorptive layer.

  11. Active Noise Control of Radiated Noise from Jets Originating NASA

    Science.gov (United States)

    Doty, Michael J.; Fuller, Christopher R.; Schiller, Noah H.; Turner, Travis L.

    2013-01-01

    The reduction of jet noise using a closed-loop active noise control system with highbandwidth active chevrons was investigated. The high frequency energy introduced by piezoelectrically-driven chevrons was demonstrated to achieve a broadband reduction of jet noise, presumably due to the suppression of large-scale turbulence. For a nozzle with one active chevron, benefits of up to 0.8 dB overall sound pressure level (OASPL) were observed compared to a static chevron nozzle near the maximum noise emission angle, and benefits of up to 1.9 dB OASPL were observed compared to a baseline nozzle with no chevrons. The closed-loop actuation system was able to effectively reduce noise at select frequencies by 1-3 dB. However, integrated OASPL did not indicate further reduction beyond the open-loop benefits, most likely due to the preliminary controller design, which was focused on narrowband performance.

  12. BWR noise spectra and application of noise analysis to FBR

    International Nuclear Information System (INIS)

    Nomura, T.

    1975-01-01

    Work related to noise analysis, in Tokyo Shibaura Electric Co. Ltd. (Toshiba) and Nippon Atomic Industry Group Co. Ltd. (NAIG) for the past several years is reviewed. After considering the Japan-United States Seminar on Reactor Noise Analysis in 1968, other subjects discussed were boiling water reactor noise analysis and work in relation to FBR. Parts of these are related to each other. For example, boiling detection and temperature fluctuations are problems pertinent to both fields. As the main problems in zero-power-reactor noise are now basically understood, only a brief description of the experiments involving the advanced two detector method is made. Focus is rather placed on the area of power plant noise. (author)

  13. Low noise control valve

    International Nuclear Information System (INIS)

    Christie, R.S.

    1975-01-01

    Noise is one of the problems associated with the use of any type of control valve in systems involving the flow of fluids. The advent of OSHA standards has prompted control valve manufacturers to design valves with special trim to lower the sound pressure level to meet these standards. However, these levels are in some cases too high, particularly when a valve must be located in or near an area where people are working at tasks requiring a high degree of concentration. Such locations are found around and near research devices and in laboratory-office areas. This paper describes a type of fluid control device presently being used at PPL as a bypass control valve in deionized water systems and designed to reduce sound pressure levels considerably below OSHA standards. Details of the design and construction of this constant pressure drop variable flow control valve are contained in the text and are shown in photographs and drawings. Test data taken are included

  14. Neutron background estimates in GESA

    Directory of Open Access Journals (Sweden)

    Fernandes A.C.

    2014-01-01

    Full Text Available The SIMPLE project looks for nuclear recoil events generated by rare dark matter scattering interactions. Nuclear recoils are also produced by more prevalent cosmogenic neutron interactions. While the rock overburden shields against (μ,n neutrons to below 10−8 cm−2 s−1, it itself contributes via radio-impurities. Additional shielding of these is similar, both suppressing and contributing neutrons. We report on the Monte Carlo (MCNP estimation of the on-detector neutron backgrounds for the SIMPLE experiment located in the GESA facility of the Laboratoire Souterrain à Bas Bruit, and its use in defining additional shielding for measurements which have led to a reduction in the extrinsic neutron background to ∼ 5 × 10−3 evts/kgd. The calculated event rate induced by the neutron background is ∼ 0,3 evts/kgd, with a dominant contribution from the detector container.

  15. A definition of background independence

    International Nuclear Information System (INIS)

    Gryb, Sean

    2010-01-01

    We propose a definition for background (in)/dependence in dynamical theories of the evolution of configurations that have a continuous symmetry and test this definition on particle models and on gravity. Our definition draws from Barbour's best matching framework developed for the purpose of implementing spatial and temporal relationalism. Among other interesting theories, general relativity can be derived within this framework in novel ways. We study the detailed canonical structure of a wide range of best matching theories and show that their actions must have a local gauge symmetry. When gauge theory is derived in this way, we obtain at the same time a conceptual framework for distinguishing between background-dependent and -independent theories. Gauge invariant observables satisfying Kuchar's criterion are identified and, in simple cases, explicitly computed. We propose a procedure for inserting a global background time into temporally relational theories. Interestingly, using this procedure in general relativity leads to unimodular gravity.

  16. Generative electronic background music system

    International Nuclear Information System (INIS)

    Mazurowski, Lukasz

    2015-01-01

    In this short paper-extended abstract the new approach to generation of electronic background music has been presented. The Generative Electronic Background Music System (GEBMS) has been located between other related approaches within the musical algorithm positioning framework proposed by Woller et al. The music composition process is performed by a number of mini-models parameterized by further described properties. The mini-models generate fragments of musical patterns used in output composition. Musical pattern and output generation are controlled by container for the mini-models - a host-model. General mechanism has been presented including the example of the synthesized output compositions

  17. Generative electronic background music system

    Energy Technology Data Exchange (ETDEWEB)

    Mazurowski, Lukasz [Faculty of Computer Science, West Pomeranian University of Technology in Szczecin, Zolnierska Street 49, Szczecin, PL (Poland)

    2015-03-10

    In this short paper-extended abstract the new approach to generation of electronic background music has been presented. The Generative Electronic Background Music System (GEBMS) has been located between other related approaches within the musical algorithm positioning framework proposed by Woller et al. The music composition process is performed by a number of mini-models parameterized by further described properties. The mini-models generate fragments of musical patterns used in output composition. Musical pattern and output generation are controlled by container for the mini-models - a host-model. General mechanism has been presented including the example of the synthesized output compositions.

  18. Noise from wind power plants

    International Nuclear Information System (INIS)

    Ljunggren, S.

    2001-12-01

    First, the generation of noise at wind power plants and the character of the sound is described. The propagation of the sound and its dependence on the structure of the ground and on wind and temperature is treated next. Models for calculation of the noise emission are reviewed and examples of applications are given. Different means for reducing the disturbances are described

  19. Road traffic noise and stroke

    DEFF Research Database (Denmark)

    Sørensen, Mette; Hvidberg, Martin; Andersen, Zorana J

    2011-01-01

    Epidemiological studies suggest that long-term exposure to road traffic noise increases the risk of cardiovascular disorders. The aim of this study was to investigate the relation between exposure to road traffic noise and risk for stroke, which has not been studied before....

  20. Noise pollution: a modem plague.

    Science.gov (United States)

    Goines, Lisa; Hagler, Louis

    2007-03-01

    Noise is defined as unwanted sound. Environmental noise consists of all the unwanted sounds in our communities except that which originates in the workplace. Environmental noise pollution, a form of air pollution, is a threat to health and well-being. It is more severe and widespread than ever before, and it will continue to increase in magnitude and severity because of population growth, urbanization, and the associated growth in the use of increasingly powerful, varied, and highly mobile sources of noise. It will also continue to grow because of sustained growth in highway, rail, and air traffic, which remain major sources of environmental noise. The potential health effects of noise pollution are numerous, pervasive, persistent, and medically and socially significant. Noise produces direct and cumulative adverse effects that impair health and that degrade residential, social, working, and learning environments with corresponding real (economic) and intangible (well-being) losses. It interferes with sleep, concentration, communication, and recreation. The aim of enlightened governmental controls should be to protect citizens from the adverse effects of airborne pollution, including those produced by noise. People have the right to choose the nature of their acoustical environment; it should not be imposed by others.

  1. Noise exposure and public health

    NARCIS (Netherlands)

    Passchier-Vermeer, W.; Passchier, W.F.

    2000-01-01

    Exposure to noise constitutes a health risk. There is sufficient scientific evidence that noise exposure can induce hearing impairment, hypertension and ischemic heart disease, annoyance, sleep disturbance, and decreased school performance. For other effects such as changes in the immune system and

  2. An inexpensive sensor for noise.

    Science.gov (United States)

    Hallett, Laura; Tatum, Marcus; Thomas, Geb; Sousan, Sinan; Koehler, Kirsten; Peters, Thomas

    2018-02-08

    Noise is a pervasive workplace hazard that varies spatially and temporally. The cost of direct-reading instruments for noise hampers their use in a network. The objectives for this work were to (1) develop an inexpensive noise sensor (noise sensors for use in an inexpensive sensor network. The inexpensive noise sensor consists of an electret condenser microphone, an amplifier circuit, and a microcontroller with a small form factor (28 mm by 47 mm by 9 mm) than can be operated as a stand-alone unit. Laboratory tests were conducted to evaluate 50 of the new sensors at 5 sound levels: (1) ambient sound in a quiet office; (2) a pink noise test signal from 65 to 85 dBA in 10 dBA increments; and (3) 94 dBA using a SLM calibrator. Ninety-four percent of the noise sensors (n = 46) were within ± 2 dBA of the SLM for sound levels from 65 dBA to 94 dBA. As sound level increased, bias decreased, ranging from 18.3% in the quiet office to 0.48% at 94 dBA. Overall bias of the sensors was 0.83% across the 75 dBA to 94 dBA range. These sensors are available for a variety of uses and can be customized for many applications, including incorporation into a stationary sensor network for continuous monitoring of noise in manufacturing environments.

  3. Prop-fan noise propagation

    Science.gov (United States)

    1989-02-07

    This report summarizes studies of enroute propfan noise propagation involving noise data obtained by DOT/TSC at ground stations during fly-over tests on October 30-31, 1987. These data have been analsyzed by DOT/TSC for comparison with in flight data...

  4. Context-dependent effects of noise on echolocation pulse characteristics in free-tailed bats.

    Science.gov (United States)

    Tressler, Jedediah; Smotherman, Michael S

    2009-10-01

    Background noise evokes a similar suite of adaptations in the acoustic structure of communication calls across a diverse range of vertebrates. Echolocating bats may have evolved specialized vocal strategies for echolocating in noise, but also seem to exhibit generic vertebrate responses such as the ubiquitous Lombard response. We wondered how bats balance generic and echolocation-specific vocal responses to noise. To address this question, we first characterized the vocal responses of flying free-tailed bats (Tadarida brasiliensis) to broadband noises varying in amplitude. Secondly, we measured the bats' responses to band-limited noises that varied in the extent of overlap with their echolocation pulse bandwidth. We hypothesized that the bats' generic responses to noise would be graded proportionally with noise amplitude, total bandwidth and frequency content, and consequently that more selective responses to band-limited noise such as the jamming avoidance response could be explained by a linear decomposition of the response to broadband noise. Instead, the results showed that both the nature and the magnitude of the vocal responses varied with the acoustic structure of the outgoing pulse as well as non-linearly with noise parameters. We conclude that free-tailed bats utilize separate generic and specialized vocal responses to noise in a context-dependent fashion.

  5. Context-dependent effects of noise on echolocation pulse characteristics in free-tailed bats

    Science.gov (United States)

    Smotherman, Michael S.

    2010-01-01

    Background noise evokes a similar suite of adaptations in the acoustic structure of communication calls across a diverse range of vertebrates. Echolocating bats may have evolved specialized vocal strategies for echolocating in noise, but also seem to exhibit generic vertebrate responses such as the ubiquitous Lombard response. We wondered how bats balance generic and echolocation-specific vocal responses to noise. To address this question, we first characterized the vocal responses of flying free-tailed bats (Tadarida brasiliensis) to broadband noises varying in amplitude. Secondly, we measured the bats’ responses to band-limited noises that varied in the extent of overlap with their echolocation pulse bandwidth. We hypothesized that the bats’ generic responses to noise would be graded proportionally with noise amplitude, total bandwidth and frequency content, and consequently that more selective responses to band-limited noise such as the jamming avoidance response could be explained by a linear decomposition of the response to broadband noise. Instead, the results showed that both the nature and the magnitude of the vocal responses varied with the acoustic structure of the outgoing pulse as well as non-linearly with noise parameters. We conclude that free-tailed bats utilize separate generic and specialized vocal responses to noise in a context-dependent fashion. PMID:19672604

  6. Circuit models and experimental noise measurements of micropipette amplifiers for extracellular neural recordings from live animals.

    Science.gov (United States)

    Chen, Chang Hao; Pun, Sio Hang; Mak, Peng Un; Vai, Mang I; Klug, Achim; Lei, Tim C

    2014-01-01

    Glass micropipettes are widely used to record neural activity from single neurons or clusters of neurons extracellularly in live animals. However, to date, there has been no comprehensive study of noise in extracellular recordings with glass micropipettes. The purpose of this work was to assess various noise sources that affect extracellular recordings and to create model systems in which novel micropipette neural amplifier designs can be tested. An equivalent circuit of the glass micropipette and the noise model of this circuit, which accurately describe the various noise sources involved in extracellular recordings, have been developed. Measurement schemes using dead brain tissue as well as extracellular recordings from neurons in the inferior colliculus, an auditory brain nucleus of an anesthetized gerbil, were used to characterize noise performance and amplification efficacy of the proposed micropipette neural amplifier. According to our model, the major noise sources which influence the signal to noise ratio are the intrinsic noise of the neural amplifier and the thermal noise from distributed pipette resistance. These two types of noise were calculated and measured and were shown to be the dominating sources of background noise for in vivo experiments.

  7. Circuit Models and Experimental Noise Measurements of Micropipette Amplifiers for Extracellular Neural Recordings from Live Animals

    Directory of Open Access Journals (Sweden)

    Chang Hao Chen

    2014-01-01

    Full Text Available Glass micropipettes are widely used to record neural activity from single neurons or clusters of neurons extracellularly in live animals. However, to date, there has been no comprehensive study of noise in extracellular recordings with glass micropipettes. The purpose of this work was to assess various noise sources that affect extracellular recordings and to create model systems in which novel micropipette neural amplifier designs can be tested. An equivalent circuit of the glass micropipette and the noise model of this circuit, which accurately describe the various noise sources involved in extracellular recordings, have been developed. Measurement schemes using dead brain tissue as well as extracellular recordings from neurons in the inferior colliculus, an auditory brain nucleus of an anesthetized gerbil, were used to characterize noise performance and amplification efficacy of the proposed micropipette neural amplifier. According to our model, the major noise sources which influence the signal to noise ratio are the intrinsic noise of the neural amplifier and the thermal noise from distributed pipette resistance. These two types of noise were calculated and measured and were shown to be the dominating sources of background noise for in vivo experiments.

  8. En Route Jet Aircraft Noise Analysis

    Science.gov (United States)

    2012-12-15

    Most research into commercial noise is primarily focused on reducing the community noise, noise that the local population near an airport experiences as aircraft takeoff and land. While this type of noise may be a main driver for the noise that commu...

  9. 23 CFR 772.11 - Noise abatement.

    Science.gov (United States)

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Noise abatement. 772.11 Section 772.11 Highways FEDERAL... OF HIGHWAY TRAFFIC NOISE AND CONSTRUCTION NOISE § 772.11 Noise abatement. (a) In determining and abating traffic noise impacts, primary consideration is to be given to exterior areas. Abatement will...

  10. 23 CFR 772.19 - Construction noise.

    Science.gov (United States)

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Construction noise. 772.19 Section 772.19 Highways... ABATEMENT OF HIGHWAY TRAFFIC NOISE AND CONSTRUCTION NOISE § 772.19 Construction noise. The following general... may be affected by noise from construction of the project. The identification is to be performed...

  11. Structural Parameters of Star Clusters: Signal to Noise Effects

    Directory of Open Access Journals (Sweden)

    Narbutis D.

    2015-09-01

    Full Text Available We study the impact of photometric signal to noise on the accuracy of derived structural parameters of unresolved star clusters using MCMC model fitting techniques. Star cluster images were simulated as a smooth surface brightness distribution following a King profile convolved with a point spread function. The simulation grid was constructed by varying the levels of sky background and adjusting the cluster’s flux to a specified signal to noise. Poisson noise was introduced to a set of cluster images with the same input parameters at each node of the grid. Model fitting was performed using “emcee” algorithm. The presented posterior distributions of the parameters illustrate their uncertainty and degeneracies as a function of signal to noise. By defining the photometric aperture containing 80% of the cluster’s flux, we find that in all realistic sky background level conditions a signal to noise ratio of ~50 is necessary to constrain the cluster’s half-light radius to an accuracy better than ~20%. The presented technique can be applied to synthetic images simulating various observations of extragalactic star clusters.

  12. Cortical activity patterns predict robust speech discrimination ability in noise

    Science.gov (United States)

    Shetake, Jai A.; Wolf, Jordan T.; Cheung, Ryan J.; Engineer, Crystal T.; Ram, Satyananda K.; Kilgard, Michael P.

    2012-01-01

    The neural mechanisms that support speech discrimination in noisy conditions are poorly understood. In quiet conditions, spike timing information appears to be used in the discrimination of speech sounds. In this study, we evaluated the hypothesis that spike timing is also used to distinguish between speech sounds in noisy conditions that significantly degrade neural responses to speech sounds. We tested speech sound discrimination in rats and recorded primary auditory cortex (A1) responses to speech sounds in background noise of different intensities and spectral compositions. Our behavioral results indicate that rats, like humans, are able to accurately discriminate consonant sounds even in the presence of background noise that is as loud as the speech signal. Our neural recordings confirm that speech sounds evoke degraded but detectable responses in noise. Finally, we developed a novel neural classifier that mimics behavioral discrimination. The classifier discriminates between speech sounds by comparing the A1 spatiotemporal activity patterns evoked on single trials with the average spatiotemporal patterns evoked by known sounds. Unlike classifiers in most previous studies, this classifier is not provided with the stimulus onset time. Neural activity analyzed with the use of relative spike timing was well correlated with behavioral speech discrimination in quiet and in noise. Spike timing information integrated over longer intervals was required to accurately predict rat behavioral speech discrimination in noisy conditions. The similarity of neural and behavioral discrimination of speech in noise suggests that humans and rats may employ similar brain mechanisms to solve this problem. PMID:22098331

  13. Noise exposure in convertible automobiles.

    Science.gov (United States)

    Mikulec, A A; Lukens, S B; Jackson, L E; Deyoung, M N

    2011-02-01

    To quantify the noise exposure received while driving a convertible automobile with the top open, compared with the top closed. Five different convertible automobiles were driven, with the top both closed and open, and noise levels measured. The cars were tested at speeds of 88.5, 104.6 and 120.7 km/h. When driving with the convertible top open, the mean noise exposure ranged from 85.3 dB at 88.5 km/h to 89.9 dB at 120.7 km/h. At the tested speeds, noise exposure increased by an average of 12.4-14.6 dB after opening the convertible top. Driving convertible automobiles at speeds exceeding 88.5 km/h, with the top open, may result in noise exposure levels exceeding recommended limits, especially when driving with the convertible top open for prolonged periods.

  14. CORTICAL ENCODING OF SIGNALS IN NOISE: EFFECTS OF STIMULUS TYPE AND RECORDING PARADIGM

    Science.gov (United States)

    Billings, Curtis J.; Bennett, Keri O.; Molis, Michelle R.; Leek, Marjorie R.

    2010-01-01

    Objectives Perception-in-noise deficits have been demonstrated across many populations and listening conditions. Many factors contribute to successful perception of auditory stimuli in noise, including neural encoding in the central auditory system. Physiological measures such as cortical auditory evoked potentials can provide a view of neural encoding at the level of the cortex that may inform our understanding of listeners’ abilities to perceive signals in the presence of background noise. In order to understand signal-in-noise neural encoding better, we set out to determine the effect of signal type, noise type, and evoking paradigm on the P1-N1-P2 complex. Design Tones and speech stimuli were presented to nine individuals in quiet, and in three background noise types: continuous speech spectrum noise, interrupted speech spectrum noise, and four-talker babble at a signal-to-noise ratio of −3 dB. In separate sessions, cortical auditory evoked potentials were evoked by a passive homogenous paradigm (single repeating stimulus) and an active oddball paradigm. Results The results for the N1 component indicated significant effects of signal type, noise type, and evoking paradigm. While components P1 and P2 also had significant main effects of these variables, only P2 demonstrated significant interactions among these variables. Conclusions Signal type, noise type, and evoking paradigm all must be carefully considered when interpreting signal-in-noise evoked potentials. Furthermore, these data confirm the possible usefulness of CAEPs as an aid to understanding perception-in-noise deficits. PMID:20890206

  15. Low Background Micromegas in CAST

    DEFF Research Database (Denmark)

    Garza, J G; Aune, S.; Aznar, F.

    2014-01-01

    Solar axions could be converted into x-rays inside the strong magnetic field of an axion helioscope, triggering the detection of this elusive particle. Low background x-ray detectors are an essential component for the sensitivity of these searches. We report on the latest developments of the Micr......Solar axions could be converted into x-rays inside the strong magnetic field of an axion helioscope, triggering the detection of this elusive particle. Low background x-ray detectors are an essential component for the sensitivity of these searches. We report on the latest developments...... of the Micromegas detectors for the CERN Axion Solar Telescope (CAST), including technological pathfinder activities for the future International Axion Observatory (IAXO). The use of low background techniques and the application of discrimination algorithms based on the high granularity of the readout have led...... to background levels below 10−6 counts/keV/cm2/s, more than a factor 100 lower than the first generation of Micromegas detectors. The best levels achieved at the Canfranc Underground Laboratory (LSC) are as low as 10−7 counts/keV/cm2/s, showing good prospects for the application of this technology in IAXO...

  16. Teaching about Natural Background Radiation

    Science.gov (United States)

    Al-Azmi, Darwish; Karunakara, N.; Mustapha, Amidu O.

    2013-01-01

    Ambient gamma dose rates in air were measured at different locations (indoors and outdoors) to demonstrate the ubiquitous nature of natural background radiation in the environment and to show that levels vary from one location to another, depending on the underlying geology. The effect of a lead shield on a gamma radiation field was also…

  17. Educational Choice. A Background Paper.

    Science.gov (United States)

    Quality Education for Minorities Network, Washington, DC.

    This paper addresses school choice, one proposal to address parental involvement concerns, focusing on historical background, definitions, rationale for advocating choice, implementation strategies, and implications for minorities and low-income families. In the past, transfer payment programs such as tuition tax credits and vouchers were…

  18. Family Background and Educational Choices

    DEFF Research Database (Denmark)

    McIntosh, James; D. Munk, Martin

    enrollments, especially for females. Not only did the educational opportunities for individuals with disadvantaged backgrounds improve absolutely, but their relative position also improved. A similarly dramatic increase in attendance at university for the period 1985-2005 was found for these cohorts when...

  19. Ambient Background Particulate Compositiion Outdoor Natural Background: Interferents/Clutter

    Science.gov (United States)

    2011-08-01

    current generation of point and standoff BW detectors. Data were extracted from 2 long- term environmental background studies, which provide the rationale...cause False Alarms by these non specific biodctectors. The response of biodetection technologies to the naturally occurring bioaerosol interferents...day, and can be affected by regional and local sources. Regional sources and most local emission sources generally become dispersed and mixed

  20. The cosmic infrared background experiment

    Science.gov (United States)

    Bock, James; Battle, John; Cooray, Asantha; Kawada, Mitsunobu; Keating, Brian; Lange, Andrew; Lee, Dae-Hea; Matsumoto, Toshio; Matsuura, Shuji; Pak, Soojong; Renbarger, Tom; Sullivan, Ian; Tsumura, Kohji; Wada, Takehiko; Watabe, Toyoki

    2006-03-01

    The extragalactic background, based on absolute measurements reported by DIRBE and IRTS at 1.2 and 2.2 μm, exceeds the brightness derived from galaxy counts by up to a factor 5. Furthermore, both DIRBE and the IRTS report fluctuations in the near-infrared sky brightness that appear to have an extra-galactic origin, but are larger than expected from local ( z = 1-3) galaxies. These observations have led to speculation that a new class of high-mass stars or mini-quasars may dominate primordial star formation at high-redshift ( z ˜ 10-20), which, in order to explain the excess in the near-infrared background, must be highly luminous but produce a limited amount of metals and X-ray photons. Regardless of the nature of the sources, if a significant component of the near-infrared background comes from first-light galaxies, theoretical models generically predict a prominent near-infrared spectral feature from the redshifted Lyman cutoff, and a distinctive fluctuation power spectrum. We are developing a rocket-borne instrument (the Cosmic Infrared Background ExpeRiment, or CIBER) to search for signatures of primordial galaxy formation in the cosmic near-infrared extra-galactic background. CIBER consists of a wide-field two-color camera, a low-resolution absolute spectrometer, and a high-resolution narrow-band imaging spectrometer. The cameras will search for spatial fluctuations in the background on angular scales from 7″ to 2°, where a first-light galaxy signature is expected to peak, over a range of angular scales poorly covered by previous experiments. CIBER will determine if the fluctuations reported by the IRTS arise from first-light galaxies or have a local origin. In a short rocket flight CIBER has sensitivity to probe fluctuations 100× fainter than IRTS/DIRBE, with sufficient resolution to remove local-galaxy correlations. By jointly observing regions of the sky studied by Spitzer and ASTRO-F, CIBER will build a multi-color view of the near

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

    International Nuclear Information System (INIS)

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

    1984-01-01

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

  2. Impact of cyclostationarity on fan broadband noise prediction

    Science.gov (United States)

    Wohlbrandt, A.; Kissner, C.; Guérin, S.

    2018-04-01

    One of the dominant noise sources of modern Ultra High Bypass Ratio (UHBR) engines is the interaction of the rotor wakes with the leading edges of the stator vanes in the fan stage. While the tonal components of this noise generation mechanism are fairly well understood by now, the broadband components are not. This calls to further the understanding of the broadband noise generation in the fan stage. This article introduces a new extension to the Random Particle Mesh (RPM) method, which accommodates in-depth studies of the impact of cyclostationary wake characteristics on the broadband noise in the fan stage. The RPM method is used to synthesize a turbulence field in the stator domain using a URANS simulation characterized by time-periodic turbulence and mean flow. The rotor-stator interaction noise is predicted by a two-dimensional CAA computation of the stator cascade. The impact of cyclostationarity is decomposed into various effects, which are separately investigated. This leads to the finding that the periodic turbulent kinetic energy (TKE) and periodic flow have only a negligible effect on the radiated sound power. The impact of the periodic integral length scale (TLS) is, however, substantial. The limits of a stationary representation of the TLS are demonstrated making this new extension to the RPM method indispensable when background and wake TKE are of comparable level. Good agreement of the predictions with measurements obtained from the 2015 AIAA Fan Broadband Noise Prediction Workshop are also shown.

  3. The Cosmic Infrared Background Experiment

    Science.gov (United States)

    Bock, James; Battle, J.; Cooray, A.; Hristov, V.; Kawada, M.; Keating, B.; Lee, D.; Matsumoto, T.; Matsuura, S.; Nam, U.; Renbarger, T.; Sullivan, I.; Tsumura, K.; Wada, T.; Zemcov, M.

    2009-01-01

    We are developing the Cosmic Infrared Background ExpeRiment (CIBER) to search for signatures of first-light galaxy emission in the extragalactic background. The first generation of stars produce characteristic signatures in the near-infrared extragalactic background, including a redshifted Ly-cutoff feature and a characteristic fluctuation power spectrum, that may be detectable with a specialized instrument. CIBER consists of two wide-field cameras to measure the fluctuation power spectrum, and a low-resolution and a narrow-band spectrometer to measure the absolute background. The cameras will search for fluctuations on angular scales from 7 arcseconds to 2 degrees, where the first-light galaxy spatial power spectrum peaks. The cameras have the necessary combination of sensitivity, wide field of view, spatial resolution, and multiple bands to make a definitive measurement. CIBER will determine if the fluctuations reported by Spitzer arise from first-light galaxies. The cameras observe in a single wide field of view, eliminating systematic errors associated with mosaicing. Two bands are chosen to maximize the first-light signal contrast, at 1.6 um near the expected spectral maximum, and at 1.0 um; the combination is a powerful discriminant against fluctuations arising from local sources. We will observe regions of the sky surveyed by Spitzer and Akari. The low-resolution spectrometer will search for the redshifted Lyman cutoff feature in the 0.7 - 1.8 um spectral region. The narrow-band spectrometer will measure the absolute Zodiacal brightness using the scattered 854.2 nm Ca II Fraunhofer line. The spectrometers will test if reports of a diffuse extragalactic background in the 1 - 2 um band continues into the optical, or is caused by an under estimation of the Zodiacal foreground. We report performance of the assembled and tested instrument as we prepare for a first sounding rocket flight in early 2009. CIBER is funded by the NASA/APRA sub-orbital program.

  4. An Analytical Solution for Signal Background and Signal to background Ratio for a Low Frequency Active Sonar in a Pekerisch Waveguide Satisfying Lambert's Rule

    NARCIS (Netherlands)

    Ainslie, M.A.; Harrison, C.H.; Zampolli, M.

    2011-01-01

    Previously published equations for the time dependence of the echo and reverberation in a Pekeris waveguide are combined with an expression derived for surface-generated noise. These closed form solutions are applied to the calculation of signal to reverberation ratio and signal to total background

  5. A matrix formulation for noise transduction as a general case of noise measure

    OpenAIRE

    Hallgren, Robert B.

    1992-01-01

    Conventional noise characteristics of an active device or circuit are given by the minimum noise figure, the optimum source reflection coefficient, and a noise resistance. The noise measure proposed extends the noise figure to include the available gain of the network, for the case of a conjugate output match, and gives values that minimize the noise power available from the network consistent with maximum available gain. Noise transduction follows as a general case of the noise measure by us...

  6. Noise Residual Learning for Noise Modeling in Distributed Video Coding

    DEFF Research Database (Denmark)

    Luong, Huynh Van; Forchhammer, Søren

    2012-01-01

    Distributed video coding (DVC) is a coding paradigm which exploits the source statistics at the decoder side to reduce the complexity at the encoder. The noise model is one of the inherently difficult challenges in DVC. This paper considers Transform Domain Wyner-Ziv (TDWZ) coding and proposes...... noise residual learning techniques that take residues from previously decoded frames into account to estimate the decoding residue more precisely. Moreover, the techniques calculate a number of candidate noise residual distributions within a frame to adaptively optimize the soft side information during...

  7. Observing a Gravitational Wave Background With Lisa

    National Research Council Canada - National Science Library

    Tinto, M; Armstrong, J; Estabrook, F

    2000-01-01

    ... formation of several observables. All are independent of lasers and frequency standard phase fluctuations, but have different couplings to gravitational waves and to the various LISA instrumental noises...

  8. Effects of noise on speech recognition: Challenges for communication by service members.

    Science.gov (United States)

    Le Prell, Colleen G; Clavier, Odile H

    2017-06-01

    Speech communication often takes place in noisy environments; this is an urgent issue for military personnel who must communicate in high-noise environments. The effects of noise on speech recognition vary significantly according to the sources of noise, the number and types of talkers, and the listener's hearing ability. In this review, speech communication is first described as it relates to current standards of hearing assessment for military and civilian populations. The next section categorizes types of noise (also called maskers) according to their temporal characteristics (steady or fluctuating) and perceptive effects (energetic or informational masking). Next, speech recognition difficulties experienced by listeners with hearing loss and by older listeners are summarized, and questions on the possible causes of speech-in-noise difficulty are discussed, including recent suggestions of "hidden hearing loss". The final section describes tests used by military and civilian researchers, audiologists, and hearing technicians to assess performance of an individual in recognizing speech in background noise, as well as metrics that predict performance based on a listener and background noise profile. This article provides readers with an overview of the challenges associated with speech communication in noisy backgrounds, as well as its assessment and potential impact on functional performance, and provides guidance for important new research directions relevant not only to military personnel, but also to employees who work in high noise environments. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Model-based temperature noise monitoring methods for LMFBR core anomaly detection

    International Nuclear Information System (INIS)

    Tamaoki, Tetsuo; Sonoda, Yukio; Sato, Masuo; Takahashi, Ryoichi.

    1994-01-01

    Temperature noise, measured by thermocouples mounted at each core fuel subassembly, is considered to be the most useful signal for detecting and locating local cooling anomalies in an LMFBR core. However, the core outlet temperature noise contains background noise due to fluctuations in the operating parameters including reactor power. It is therefore necessary to reduce this background noise for highly sensitive anomaly detection by subtracting predictable components from the measured signal. In the present study, both a physical model and an autoregressive model were applied to noise data measured in the experimental fast reactor JOYO. The results indicate that the autoregressive model has a higher precision than the physical model in background noise prediction. Based on these results, an 'autoregressive model modification method' is proposed, in which a temporary autoregressive model is generated by interpolation or extrapolation of reference models identified under a small number of different operating conditions. The generated autoregressive model has shown sufficient precision over a wide range of reactor power in applications to artificial noise data produced by an LMFBR noise simulator even when the coolant flow rate was changed to keep a constant power-to-flow ratio. (author)

  10. Accuracy of Cochlear Implant Recipients on Speech Reception in Background Music

    Science.gov (United States)

    Gfeller, Kate; Turner, Christopher; Oleson, Jacob; Kliethermes, Stephanie; Driscoll, Virginia

    2012-01-01

    Objectives This study (a) examined speech recognition abilities of cochlear implant (CI) recipients in the spectrally complex listening condition of three contrasting types of background music, and (b) compared performance based upon listener groups: CI recipients using conventional long-electrode (LE) devices, Hybrid CI recipients (acoustic plus electric stimulation), and normal-hearing (NH) adults. Methods We tested 154 LE CI recipients using varied devices and strategies, 21 Hybrid CI recipients, and 49 NH adults on closed-set recognition of spondees presented in three contrasting forms of background music (piano solo, large symphony orchestra, vocal solo with small combo accompaniment) in an adaptive test. Outcomes Signal-to-noise thresholds for speech in music (SRTM) were examined in relation to measures of speech recognition in background noise and multi-talker babble, pitch perception, and music experience. Results SRTM thresholds varied as a function of category of background music, group membership (LE, Hybrid, NH), and age. Thresholds for speech in background music were significantly correlated with measures of pitch perception and speech in background noise thresholds; auditory status was an important predictor. Conclusions Evidence suggests that speech reception thresholds in background music change as a function of listener age (with more advanced age being detrimental), structural characteristics of different types of music, and hearing status (residual hearing). These findings have implications for everyday listening conditions such as communicating in social or commercial situations in which there is background music. PMID:23342550

  11. Signal with Flat Phase Noise Using a Carrier and the Power Spectral Density of White Noise for Phase Noise Standards

    Science.gov (United States)

    Watabe, Ken-ichi; Yanagimachi, Shinya; Ikegami, Takeshi; Iida, Hitoshi; Shimada, Yozo

    2012-01-01

    We have realized a phase noise standard of a signal with a -100 dBc/Hz flat phase noise at 10 MHz for Fourier frequencies of 1 Hz to 100 kHz, which ensures traceability to the International System of Units (SI). The flat phase noise signal is produced using a carrier combined with white noise. To ensure traceability, both the flat phase noise signal power and the power spectral density of white noise are determined with a calibrated power meter and the noise standard, respectively. The flatness of the phase noise standard is within ±0.7 dB.

  12. Noise and detection in ''optical'' modulation spectroscopy

    International Nuclear Information System (INIS)

    Montelatici, V.

    1975-01-01

    The measuring techniques suitable for ''optical'' modulation spectroscopy are analyzed and source of noise identified. The choice of optical detector is for photoelectrical devices. It is shown that the shot noise of phototubes is the most important noise source

  13. Reduction of fan noise: A concept

    Science.gov (United States)

    Simonson, M. R.

    1972-01-01

    Acoustic materials strategically located within or near noise sources are effective for noise abatement on wing mounted lift fans, nozzles, engines and other noise sources. Panels are straightforward and easily adaptable to situations outside of aircraft technology.

  14. Highway renewable energy : photovoltaic noise barriers

    Science.gov (United States)

    2017-07-01

    Highway photovoltaic noise barriers (PVNBs) represent the combination of noise barrier systems and photovoltaic systems in order to mitigate traffic noise while simultaneously producing renewable energy. First deployed in Switzerland in 1989, PVNBs a...

  15. CERL Noise Monitoring and Warning System 98

    National Research Council Canada - National Science Library

    Sachs, Daniel

    1999-01-01

    .... This report documents the design and construction of this new noise monitor. The heart of wind-noise resistance is a two- microphone array and special signal processing to identify and separate blast sounds from pseudo- wind noise...

  16. Green noise wall construction and evaluation.

    Science.gov (United States)

    2011-09-01

    This report details the research performed under Phase I of a research study titled Green Noise Wall Construction and Evaluation that looks into the feasibility of using green noise barriers as a noise mitigation option in Ohio. This phase incl...

  17. Keeping Noise Down on the Farm

    Science.gov (United States)

    ... Do > Keeping Noise Down on the Farm Keeping Noise Down on the Farm SHARE Some people may ... risks permanent hearing damage. Take steps to reduce noise from machinery. Keep machinery running smoothly by replacing ...

  18. The Assessment of Noise Exposure and Noise Annoyance at a Petrochemical Company

    Directory of Open Access Journals (Sweden)

    S. Farhang Dehghan

    2013-12-01

    .Conclusion: Based on the obtained results of investigating the noise level (objective exposure as well as the noise annoyance (subjective exposure at the studied company, it is necessary to adopt the management –technical noise reduction measures at manufacturing sectors as the personal noise exposure and environmental noise exposure and also noise personal exposure of administrative staff can be decreased.

  19. The role of Urbis' noise and noise effects maps in local policy

    NARCIS (Netherlands)

    Borst, H.C.

    2001-01-01

    An important aspect of the EU noise policy is mapping of noise and noise effects and the formulation of noise action plans. In the Netherlands, due to the new policy on noise (MIG), the municipalities will be responsible for the formulation of a local noise policy. An instrument for the assessment

  20. Does ambient noise or hypobaric atmosphere influence olfactory and gustatory function?

    Science.gov (United States)

    Rahne, Torsten; Köppke, Robert; Nehring, Michael; Plontke, Stefan K; Fischer, Hans-Georg

    2018-01-01

    Multidimensional food perception is based mainly on gustatory and olfactory function. Recent research has demonstrated that hypobaric pressure impairs gustatory function and that background noise or distracting auditory stimulation impairs olfactory function. Using a hypobaric chamber, the odor identification, discrimination, and thresholds as well as taste identification and threshold scores were measured in 16 healthy male volunteers under normal and hypobaric (6380 ft) conditions using clinically validated tests. In both conditions, background noise was either canceled out or replaced by white noise presentation (70 dB sound pressure level). Olfactory sensitivity for n-butanol and gustatory sensitivity were impaired in a hypobaric atmosphere. White noise did not influence the odor test results. White noise stimulation impaired sensitivity for sour and sweet but not for bitter or salty tastants. We conclude that hypobaric or noisy environments could impair gustatory and olfactory sensitivity selectively for particular tastants and odorants.