• The Journal of the Acoustical Society of Korea
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• v.29 no.3
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• pp.184-190
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• 2010

Lowering of auditory caused by noise is increased, these days. Especially, people who have noise induced hearing loss by permanent exposure to noise are increased according to spread out of multimedia and improvement of information equipment. The pure tone audiometry used in the hospital presently inspect auditory manually up to 8,000 Hz bandwidth. So the case of noise induced hearing loss which suffered from extended high frequency over 8,000 Hz, there is a problem to prevent hearing loss by precognition. In this paper, we proposed a method to prevent noise induced hearing loss by using extended high frequency bandwidth from 12,000 Hz to 20,000 Hz. We have got a experimental result to fifty of twenties who are often used to earphones through portable equipment. As a result, 36% of twenties show lowering of auditory caused by noise and 2% of them shows severe loss of hearing.

• Korean Journal of Environment and Ecology
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• v.25 no.6
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• pp.853-860
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• 2011

We measured blood plasma parameters(cortisol, glucose, albumin) and glucocorticoid receptor(GCR) gene expression level of the Japanese eel(Anguilla japonica) exposed to an explosion noise for an hour in order to evaluate the effects of noise stress and to explore the possibility of these parameters as biomarkers on noise stress for one of this valuable aquaculture species. Plasma cortisol and glucose reached high levels with significant differences compared to the control group, whereas albumin showed a low value after 1 h of exposure. In addition, tissue distribution of GCR gene expression was studied by real-time RT-PCR of ten organs(brain, eye, gill, gonad, heart, intestine, kidney, liver, muscle and skin). Liver showed the highest level of expression in the control followed by gill, muscle and intestine. A time-course study revealed induction in liver, gill, muscle and intestine after 30 min or 1 h of noise exposure.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.2
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• pp.185-195
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• 2020

Objectives: The purpose of this study was to analyze noise exposure levels and the rate of exceedance of exposure limits in workplaces from a 2015 measurement of working environments according to area, industry, and scale of workplace and to determine changes compared to the past. Methods: Among the 408,875 measurements of noise in working environments from 27,030 workplaces in 2015, 16,359 workplaces that were linked to special health examination data were selected as the subjects of this study. The eight-hour corrected measurements and geometric mean values of the individual noise measurements of the workplaces were used to calculate noise exposure levels and the exceedance rate of exposure limits. Results: The average noise exposure level of the overall workplaces making up the subjects of this study was 83.6 dBA, and the exceedance rate of exposure limits was 15.1%. At least half of the noise measurements exceeded the exposure limits in 13.7% of the workplaces. Noise exposure levels were higher in the manufacturing industry and in smaller-scale workplaces. The exceedance rate of noise exposure limits was higher in the mining and manufacturing industries and in smaller-scale workplaces. Conclusions: Noise exposure has shown improvements compared to the past, but the exceedance rate of exposure limits was still high, and more than half of the workers were being exposed to noise of 85 dBA or higher. Therefore, it is necessary to make more active improvements in working environments in terms of noise exposure.

• The Journal of the Acoustical Society of Korea
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• v.31 no.6
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• pp.359-366
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• 2012

Today, people are exposed to the various noisy environments, such as in the buses, subway and supermarkets where there are a lot of people. The noise issue is getting more serious as people want to use portable sound equipment and mobile phones even under this noisy condition. People want to use the portable equipment to exchange the information freely and they set the volume as 15dB higher than the noise around them, which almost reach at 110 dB. That amount of sound can cause noise induced deafness to the users and another issue to the others as additional noise source. A Bone-conduction system can be a solution to reduce noise and enhance voice signal of mobile phone. In this paper, we propose the way of cancelling noise and enhancing speech signal of mobile phones, by installing bone-conduction feedback system with ordinary mobile phones. With this system, we can reduce the environment noise and enhance the voice quality of mobile phones. Using this method, we can enhance the signal by around 17 dB.

• Journal of Advanced Navigation Technology
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• v.23 no.4
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• pp.265-272
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• 2019

In this paper, we selected commuting scenarios in the most congested metropolitan area in Korea, and conducted noise analysis during personal air vehicle (PAV) operation using aviation environmental design tool (AEDT)software which was developed by Federal Aviation Administration (FAA). Noise is the second important factor after safety in order to operate PAVs through concepts such as ODM (on-demand mobility) introduced by National Aeronautics and Space Administration (NASA). Noise analysis were performed by modeling low-noise ePAVs as commercial helicopters and predicted residential suitability in order to resolve problems in which accurate NPD (noise power distance) data from PAVs were not released. The application of noise reduction technology such as electric propulsion has significantly reduced noise exposure levels and has reached the conclusion that commuting with PAVs is feasible without noise problems in the metropolitan area.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.5
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• pp.400-407
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• 2011

The suggested method of previous Son's study dichotomized subjective response data to modeling noise exposure-response. The method used maximum liklihood estimation instead of least square estimation and the noise exposure-response curve of the study was logistic regression analysis result. The method was originated to modeling community response rate such as %HA or %A. It can be useful when the subjective response was investigated based on predicted noise level. It is difficult to measure the single source emitting noise such as railway because various traffic noise sources combined in our life. The suggested method was adopted to model in this study and railway noise-exposure response curves were modeled because the noise level of this area was predicted data. The data of this study was used by previous Ko's paper but he dealt the area as combined noise area and divided the data by dominant noise source. But this study used all data of this area because the annoyance response to railway noise was higher than other noise according to the result of correlation analysis. The trend of the %HA and %A prediction model to train noise of this study is almost same as the model based on measured noise of previous Lim's study although the investigated areas and methods were different.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.948-951
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• 2014

Road traffic noise is closely related with urban forms and urban components, such as population, building, traffic and land-use, etc. Hence, it is possible to minimize the noise exposure problem depending on how to plan new town or urban planning alteration. This paper provides ways to apply for urban planning in consideration of noise through exposed noise estimation for urban planning alteration. Spatial autoregressive model which explains about 81.4% of road traffic noise from the former paper is used. The simulation results by the spatial statistical model are compared with those by the engineering program-based modeling for 5 small-scaled scenarios of urban planning alteration. The error from the limitation of containing informations inside the grid cell and the difficulties of reflecting acoustic phenomena is existed. Nevertheless, in the stage of preliminary design, the use of the statistical models that have been estimated well is useful in time and economically.

• Journal of the Korea Institute of Building Construction
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• v.11 no.3
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• pp.310-318
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• 2011

Due to the lack of a noise and vibration survey for military air bases, noise and vibration are not taken into consideration for new installations, which has resulted in a number of problems, including the separation of tiles. Furthermore, it is not possible to establish appropriate counter-vibration plans to minimize damage resulting from vibration on structures, since no standard is in place when location for residence areas, including military quarters, is determined. In this context, this research includes a noise and vibration survey, on which basis a quantitative evaluation model for vibration of structure by aircraft noise is generated, as well as through linear regression analysis, and suggests installation standards by purpose of structure, minimizing the damage due to noise and vibration, and establishing appropriate counter-vibration plans for future installation and repairs of on-base structures in the military bases.

• Korean Journal of Psychosomatic Medicine
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• v.8 no.2
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• pp.181-190
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• 2000

This study describes the relationships between aircraft noise and stress and subjective noisy perception by comparing with two areas where the airport is adjacent or not. One area is Yipam-dong and Hak-dong expected to have louder aircraft noise because Kangnung Airport is near the area, and the other area is Songjung-dong as a control. For this study, we used telephone-survey which was targeted to two hundreds people of each area through the random sampling method. The design of the study is cross sectional study and the unit of analysis is a person. As the result of the multiple regression and logistic analysis, under the control of the other control variables, the both stress levels and subjective noisy perception of Yipam-dong and Hak-dong people significantly higher than that of Songjung-dong people and the people graduated middle school had significantly higher both stress levels and subjective noisy perception than the people graduated high school. In the future more studies have to be made that include concrete medical and psychiatric health problems.

• Journal of Korea Spatial Information System Society
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• v.9 no.3
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• pp.17-24
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• 2007

The noise problem is one of the major problems associated with large cities and is considered important factor not only in maintenance but also in development of cities. Accordingly, the noise map is being increasingly used in city planning and design. However, the existing two-dimensional noise maps only show regional, planar distribution of noise. This study presented a method to build a data model for analyzing and visualizing noise levels at fine scale considering the vertical distribution of noise in a building. By expanding the 2D topology concept used in conventional GIS to 3D, it suggested a 3D GIS data model that makes 3D spatial queries, analyses and visualization possible and applied the proposed approach to building a 3D noise information system. By building and testing the system, the study showed different functionalities including 3D spatial queries and 3D visualization of noise levels varying temporally or according as the height of sound-proof walls. In each case, the population exposed to noise was quantitatively computed to illustrate the potential in the areas of city planning and design.