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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The Effects of a Masking Noise Upon the Performance of a Simple Motor Task Comparing Brain-Injured and Non-Brain-Injured Children

Moss, Barbara A. 08 1900 (has links)
Two questions can be posed for study: 1) Will the effect of auditory masking provided by a clinical noise significantly affect the performance of hearing children on the Knox Cube Test? 2) Are there significant differences among brain-injured, mentally, retarded, and "normal" children in ability to adjust to auditory masking in the performance of the Knox Cube Test?
2

Wavelet and filterbank modelling of the normal and impaired auditory system

Li, Min January 1998 (has links)
No description available.
3

Vocal response times to acoustic stimuli in white whales and bottlenose dolphins

Blackwood, Diane Joyner 30 September 2004 (has links)
Response times have been used to explore cognitive and perceptual processes since 1850 (Donders, 1868). The technique has primarily been applied to humans, birds, and terrestrial mammals. Results from two studies are presented here that examine response times in bottlenose dolphins (Tursiops truncatus) and white whales (Delphinapterus leucas). One study concerned response times to stimuli well above the threshold of perceptibility of a stimulus, and the other concerned response times to stimuli near threshold. Two white whales (Delphinapterus leucas) and five Atlantic bottlenose dolphins (Tursiops truncatus) were presented stimuli well above threshold. The stimuli varied in type (tone versus pulse), amplitude, duration, and frequency. The average response time for bottlenose dolphins was 231.9 ms. The average response time for white whales was 584.1 ms. There was considerable variation between subjects within a species, but the difference between species was also found to be significant. In general, response times decreased with increasing stimulus amplitude. The effect of duration and frequency on response time was unclear. Two white whales (Delphinapterus leucas) and four Atlantic bottlenose dolphins (Tursiops truncatus) were given audiometric tests to determine masked hearing thresholds in open waters of San Diego Bay (Ridgway et al., 1997). Animals were tested at six frequencies over a range from 400 Hz to 30 kHz using pure tones. Hearing thresholds varied from 87.5 dB to 125.5 dB depending on the frequency, masking noise intensity and individual animal. At threshold, median response time across frequencies within each animal varied by about 150 ms. The two white whales responded significantly slower (∼670 msec, p<0.0001) than the four dolphins (∼410 msec). As in terrestrial animals, reaction time became shorter as stimulus amplitude increased (Wells, 1913; Stebbins, 1966). Across the two studies, the dolphins as a group were faster in the abovethreshold study than in the nearthreshold study. White whales had longer response times than bottlenose dolphins in both studies. Analysis of response time with an allometric relation based on weight shows that the difference in weight can explain a significant part of the difference in response time.
4

Det maskerande brusljudets påverkan på inlärningen av visuell information : om effekten av maskerande brusljud i öppna kontorslandskap / The impact of masking noise on the learning ability of visual information : the effect of masking noise in open-plan offices

Ceder, Maria, Hellström, Camilla January 2012 (has links)
Denna experimentella studie undersökte om maskerande brusljud på ovidkommande tal påverkar inlärning av visuell information. Experimentet genomfördes i ett laboratorium med 32 försöksdeltagare. Visuella ord presenterades för försöksdeltagarna samtidigt som auditivt tal från samma semantiska kategori, med eller utan maskerande brusljud, presenterades. De visuella orden skulle återges i valfri ordning. Resultatet av studien visar att ett maskerande brusljud på ovidkommande tal har positiv effekt på inlärningsförmågan. Detta visades av att försökspersonerna mindes fler visuellt presenterade ord samt att de lyckades ignorera det ovidkommande talet bättre då talet maskerades av ett brusljud jämfört med om talet inte maskerades av ett brusljud. Resultaten av studien kan med fördel tillämpas i öppna kontorslandskap. Detta då medarbetare i öppna kontorslandskap ofta utför kognitivt krävande uppgifter i en bullrig miljö innehållande bland annat bakgrundstal. Ett maskerande brusljud kan minska störningen av ovidkommande kontorsljud och ovidkommande tal och på så sätt positivt påverka arbetsprestationen. / This study examined if a masking white noise on irrelevant speech affects the encoding of visual information. An experiment was carried out in a laboratory with 32 participants. The participants were presented to a series of written words and were prompted to recall these words in any order. While the participants studied the written words, irrelevant speech from the same semantic category was presented with or without a masking noise. The participants were told to ignore the irrelevant speech. The results of this study showed that the number of intrusions from the irrelevant speech decreases and the number of recalled written words increases when the irrelevant speech is masked by a white noise compared to irrelevant speech without a masking noise. The findings of this study could be applied in the acoustic design of open-plan offices where cognitive tasks, such as reading comprehension and proofreading, are performed in a noisy environment. A white noise can reduce the intelligibility of office noise and irrelevant speech, which have positive effect on work performance.
5

Vocal response times to acoustic stimuli in white whales and bottlenose dolphins

Blackwood, Diane Joyner 30 September 2004 (has links)
Response times have been used to explore cognitive and perceptual processes since 1850 (Donders, 1868). The technique has primarily been applied to humans, birds, and terrestrial mammals. Results from two studies are presented here that examine response times in bottlenose dolphins (Tursiops truncatus) and white whales (Delphinapterus leucas). One study concerned response times to stimuli well above the threshold of perceptibility of a stimulus, and the other concerned response times to stimuli near threshold. Two white whales (Delphinapterus leucas) and five Atlantic bottlenose dolphins (Tursiops truncatus) were presented stimuli well above threshold. The stimuli varied in type (tone versus pulse), amplitude, duration, and frequency. The average response time for bottlenose dolphins was 231.9 ms. The average response time for white whales was 584.1 ms. There was considerable variation between subjects within a species, but the difference between species was also found to be significant. In general, response times decreased with increasing stimulus amplitude. The effect of duration and frequency on response time was unclear. Two white whales (Delphinapterus leucas) and four Atlantic bottlenose dolphins (Tursiops truncatus) were given audiometric tests to determine masked hearing thresholds in open waters of San Diego Bay (Ridgway et al., 1997). Animals were tested at six frequencies over a range from 400 Hz to 30 kHz using pure tones. Hearing thresholds varied from 87.5 dB to 125.5 dB depending on the frequency, masking noise intensity and individual animal. At threshold, median response time across frequencies within each animal varied by about 150 ms. The two white whales responded significantly slower (∼670 msec, p<0.0001) than the four dolphins (∼410 msec). As in terrestrial animals, reaction time became shorter as stimulus amplitude increased (Wells, 1913; Stebbins, 1966). Across the two studies, the dolphins as a group were faster in the abovethreshold study than in the nearthreshold study. White whales had longer response times than bottlenose dolphins in both studies. Analysis of response time with an allometric relation based on weight shows that the difference in weight can explain a significant part of the difference in response time.
6

A ringing phone : The distracting effect of ringtones

Liljenberg, Robin January 2017 (has links)
Ringing phones are common in work space environments in the 21th century and while capturing the attention of the call-taker they also tend to disrupt people in the surrounding environment. This study aims to investigate the attentional capturing effect of ringtones by comparing sudden and increasing onsets with quiet and noise masking conditions while participants undertook a test of short-term memory for serial order (serial recall). The experiment presented new evidence that increasing ringtone sounds have a disruptive effect on serial recall processing. A masking noise background, however, successfully eliminated the effect of the increasing ringtone sound.  In contrary to what was anticipated, the ringtone with the sudden onset did not cause an attentional capture effect, suggesting at least in behavioural terms, it was successfully ignored. The results are discussed in relation to the literature on looking effects. Increasing ringtone sounds may appear looming, with sudden onset sounds decreasing in volume appearing receding. The central idea is that looming sounds are more disruptive to serial recall because they cause a diversion of attention from the serial recall task so as to react to the apparently approaching sound. The disruption attributable to looming sounds may be a form of attentional capture that is more specific than those triggered by deviant events within a to-be-ignored stream of sounds.
7

Attentional capture by a looming ringtone

Liljenberg, Robin January 2017 (has links)
Ringtones are a common distracting sound in modern workspaces. In an earlierexperiment, ringtones increasing in volume (looming) produced greater attentional capture effectin the context of serial short-term memory, than ringtones with sudden onsets that decreased involume (receding). To determine whether this effect occurred merely because the loudest part ofthe looming ringtone coincided with the most sensitive part of the serial short-term memory task,this study repeated the sound conditions of the first experiment, but altered their timing. In thisstudy, the onset of the ringtones were brought forward in time such that the loudest part of thelooming ringtone now coincided with the part of the serial short-term memory task wherein theonset of the looming ringtone occurred in the first experiment. The looming ringtone againproduced more disruption than the receding ringtone, which failed to disrupt performance relativeto the quiet control condition. The presence of a masking sound eliminated the looming ringtoneeffect, as in the previous study. The results here support previous work demonstrating that thelooming sounds give rise to attentional capture and that this reflects an evolutionary adaptation tounconsciously react to approaching sounds/objects.

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