• Journal of Biomedical Engineering Research
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• v.33 no.1
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• pp.25-31
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• 2012

The audio vision system was developed for visually impaired people and usability was verified. In this study ten normal volunteers were included in the subject group and their mean age was 28.8 years old. Male and female ratio was 7:3. The usability of audio vision system was verified by as follows. First, volunteers learned distance of obstacles and up-down discrimination. After learning of audio vision system, indoor and outdoor walking examination was performed. The test was scored by ability of up-down and lateral discrimination, distance recognition and walking without collision. Each parameter was scored by 1 to 5. The results were 93.5 +- SD(ranges, 86 to 100) of 100. In this study, we could convert visual information to auditory information by audio-vision system and verified possibility of applying to daily life for visually impaired people.

• Journal of Fisheries and Marine Sciences Education
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• v.12 no.1
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• pp.1-10
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• 2000

In order to obtain the fundamental data on the auditory thresholds of fishes for marine ranching, the auditory thresholds of black rock fish Sebastes Schlegeli were measured in the presence of masking noise in the spectrum level range of 73 - 83dB (0dB re $1{\mu}Pa/{\sqrt{Hz}}$) with a classical cardiac conditioning technique. Critical ratios were about 19 - 30dB at 80 - 300Hz and 46 - 54dB at 500 - 800Hz. The ratio increased almost linearly with increasing frequency to 500Hz. The noise spectrum level at the start of masking was about 70dB within the frequency range of 80 - 800Hz excepting 65dB at 300Hz. This suggests that hearing of the black rock fish is masked in the natural environment with the noise spectrum level above 65dB. The sound pressure level of which the signal sound of 100 - 200Hz is recognized by black rock fish under the ambient noise is above 90dB and the critical ratio of them is above 20dB.

• Journal of Audiology & Otology
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• v.23 no.2
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• pp.83-88
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• 2019

Background and Objectives: Mild cognitive impairment (MCI) is a disorder that usually occurs in the elderly, leading to dementia in some progressive cases. The purpose of this study is to examine the utility of central auditory processing tests as early diagnostic tools for identifying the elderly with MCI. Subjects and Methods: This study was conducted on 20 elderly patients with MCI and 20 healthy matched peers. The speech perception ability in a quiet environment and in the presence of background noise and also temporal resolution were assessed by using Speech Perception in Noise (SPIN) and Gap in Noise (GIN) tests, respectively. Results: The results indicated that the ability to understand speech in a quiet environment did not differ significantly between the two groups. However, SPIN at the three signal-to-noise ratios and the temporal resolution scores were significantly different between the two groups (p<0.001). Conclusions: Individuals with MCI appear to have poorer speech comprehension in noise and a lower temporal resolution than those of the same age, but without cognitive defects. Considering the utility of these tests in identifying cognitive problems, we propose that since the GIN test seems to be less influenced by intervening factors, this test can therefore, be a useful tool for the early screening of elderly people with cognitive problems.

• Korean Journal of Audiology
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• v.23 no.2
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• pp.83-88
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• 2019

Background and Objectives: Mild cognitive impairment (MCI) is a disorder that usually occurs in the elderly, leading to dementia in some progressive cases. The purpose of this study is to examine the utility of central auditory processing tests as early diagnostic tools for identifying the elderly with MCI. Subjects and Methods: This study was conducted on 20 elderly patients with MCI and 20 healthy matched peers. The speech perception ability in a quiet environment and in the presence of background noise and also temporal resolution were assessed by using Speech Perception in Noise (SPIN) and Gap in Noise (GIN) tests, respectively. Results: The results indicated that the ability to understand speech in a quiet environment did not differ significantly between the two groups. However, SPIN at the three signal-to-noise ratios and the temporal resolution scores were significantly different between the two groups (p<0.001). Conclusions: Individuals with MCI appear to have poorer speech comprehension in noise and a lower temporal resolution than those of the same age, but without cognitive defects. Considering the utility of these tests in identifying cognitive problems, we propose that since the GIN test seems to be less influenced by intervening factors, this test can therefore, be a useful tool for the early screening of elderly people with cognitive problems.

• Journal of the Korean Institute of Educational Facilities
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• v.28 no.3
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• pp.3-14
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• 2021

Speech information of teachers is transmitted to students in classrooms so that appropriate aural environment should be provided for academic purposes. Many researches have been undertaken for classroom acoustics, and acoustic standards of domestic classrooms were suggested based on the reverberation time and background noise level. However, these standards are suitable for middle and high schools and so not consider the auditory ability by ages. As a precedent research, the present study was begun to suggest an acoustic standard for lower grade elementary school classrooms with children under age 9 who have not normal auditory ability. In order to do this, acoustic performances of the lower grade classrooms were measured and compared with the general classrooms. Also, change of acoustic parameters depending on the desk layout was measured and analyzed. The measured acoustic parameters were background noise, signal to noise ratio, RT, STI, D₅₀, and IACC. As a result, it was found that background noise is exceed the standard of 35dB(A) at the schools along the road sides. Also, it was shown that most of acoustic parameters are higher in the classrooms built recently rather than the old classrooms. Generally, there are not much difference of acoustic parameters among the various desk layouts but, better acoustic performances are acquired at the center line and the seats near sound source. Also, Higher IACC was measured at the seats on the center line facing the source squarely.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.474-477
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• 2002

Hearing loss caused by exposure to industrial machine noise results in devastating disability that is mostly preventable. And recent researches indicate that the noise may also induce hypertension and cardiovascular disease. In addition the sleep polygraph provides many indicators of sleep disturbance by the noise. In this paper we make an analysis on ball bearing machine noise, a kind of the industrial noise. The analysis of Its power spectrum is based on FFT(Fast Fourier Transform). And then the spectral results of the noise are compared with that of the spectrum for an auditory signal. The signal is measured from the pronunciation of two Koreans. Finally we suggest the most important stratagem to prevent the noise for worker's health and efficiency.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.337-338
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• 2000

The perceptual filter for speech enhancement was analytically derived where the frequency content of the input noisy signal was made the same as that of the estimated clean signal in auditory domain. However, the analytical derivation should rely on the deconvolution associated with the spreading function in the psychoacoustic model, which results in an ill-conditioned problem. In order to cope with the problem associated with the deconvolution, we propose a novel psychoacoustic model based speech enhancement filter whose principle is the same as the perceptual filter, however the filter is derived by a constrained optimization which provides solutions to the ill-conditioned problem.

• International journal of advanced smart convergence
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• v.6 no.2
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• pp.16-23
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• 2017

In contemporary modern society, people are constantly exposed to many kinds of noise, such as that from machinery, aircraft, construction sites, or road traffic. Noise is considered one of the most indispensable and influential parts of human life. This study investigates the acoustic characteristics of noise transfer from external sources to the human ear. For this study, we measured and analyzed various types of noise environments, installed monitoring speakers in a semi-anechoic room, and conducted intentional noise-filled experiments. In this environment, the size of the sounds generated by use of a portable device was also measured and the SNR (signal to noise ratio) calculated to study the influence of the noise. As sound is transmitted to the ear and the human body, it affects not only auditory damage but also other parts of the body. In this paper, we propose a proper SNR for noise emitted by portable IT equipment to prevent hearing loss when IT equipment is used.

• Journal of the Ergonomics Society of Korea
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• v.13 no.2
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• pp.43-48
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• 1994

Among many kinds of odors, some are known to have effects of sedation or stimulation on brain activity. In this study, brain activity levels affected by four kinds of fragrance0lemon, lavender, jasmine, and rose-were tested using EEG recording. In the first experiment, the quality of alpha wave was examined under controlled rest condition. In the second experiment, the event-related potential (ERP) and contingent negative variation (CNV) were investigated during a simple reaction tasks (SRT) against auditory signal. EEG data obtained for the rest condition were analyzed suing "3-Dimensional Viewer)" which was developed by ourselves to show the chaotic attractor of the signal. Power spectrum were also calculated using FET. EEG data obtained during the SRT were analyzed by comparing CNV amplitudes about each odor condition. Results confirmed the sedative effect of the lemon and the lavender, and the stimulative effect of the jasmine and the rose.

• Journal of information and communication convergence engineering
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• v.5 no.3
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• pp.245-248
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• 2007

In this paper, we research the content-based analysis and classification according to the composition of the feature parameter data base for the audio data to implement the audio data index and searching system. Audio data is classified to the primitive various auditory types. We described the analysis and feature extraction method for the feature parameters available to the audio data classification. And we compose the feature parameters data base in the index group unit, then compare and analyze the audio data centering the including level around and index criterion into the audio categories. Based on this result, we compose feature vectors of audio data according to the classification categories, and simulate to classify using discrimination function.