• 환경위생공학
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• 제17권2호
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• pp.55-62
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• 2002

For my thesis I have analyzed the differences between the traffic noise level surrounding the schools and the perceived level of noise. 1 have used the ways of measurement and questionnaires to support my study. According to the analysis, the measured noise level was higher than the expected noise level. The equivalent noise level was proven to be higher when the windows of the classrooms were open. The noise level was also higher on the third floor than the first floor. The correlation between the measured noise level and the perceived level of noise was tested in each school. The school which had a higher expected noise level showed a high perceived level of noise. The measured noise level and the perceived level of noise became larger on the higher floors. Through the questionnaires, the traffic noises were proven to be the largest noise-making source surrounding the schools. Most of the students replied on the questionnaires that they have been consistently bothered by the noise. It interfered with their studies and concentration. Also, the sound of their voices became louder because of the noise around their schools. Therefore, I have come to the conclusion that the traffic noises that surround the schools give the students negative influences.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2010년도 추계학술대회 논문집
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• pp.144-145
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• 2010

3-D noise map of Mugue Dong of the Ulsan City has been constructed. Comparing with the measured noise level, the predicted noise level has been confirmed for its accuracy. Correction factors for better prediction result using the constructed noise map have been investigated proving that its method is useful. The procedure of noise map construction method has also been introduced using RLS-90, Cadna A.

• 한국안전학회지
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• 제14권3호
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• pp.140-145
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• 1999

In this study, noise analyses were performed toward ten school and one library-building adjacent to road. In particular, noise levels measured in the case-study city were compared to those from environmental noise standard as well as to encouraged noise level. In the analyses, the following conclusions are emphasized in order to make comfortable educational learning environment. 1) When windows were open, the measured noise level of 9 schools exceeded the encouraged noise level. In order to mitigate the exceeded level, it is necessary to plant trees or lawn and install soundproofing wall. 2) When windows were closed, the measured noise level of the most schools showed lower than that of encouraged level. For sound insulation, installing both double window and casement window are required. 3) Schoolhouse's vertical arrangement from the road in order to minimize the expected noise effect, and provision of green space by which visual hiding as well as psychological comfort are presumably achieved.

• 한국소음진동공학회논문집
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• 제14권11호
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• pp.1166-1175
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• 2004

People in the advanced society have deep interest in such environmental problems as noise, air quality, water pollution, etc. This paper submits the result of the research on the noise In the surroundings of the butane can explosion location. First, the noise level measured in a residential area, 245 meters' away from the butane can explosion location, was 59.3 dB. Also, the noise level measured in the IGUP (International Graduate University of Peace), 300 meters' away from the explosion site, was 52.5 dB. Second, the above noise levels are lower than the level specified In the Environmental Standard (65 dB), which represented that the experiment was safe. Third, the noise level in a place away from the butane can explosion location varied in accordance with the direction of the wind. Consequently, the noise in all locations (the places where damage to people is expected) surrounding the experimental butane can explosion location was measured to identify the effect of the wind irection.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 춘계학술대회 논문집
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• pp.603-608
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• 2002

Sound absorbing materials are applied to the exposed surfaces of curved subway tunnel for the reduction of curving noise level. Before the treatment, acoustical engineering simulation is performed to predict the noise level reduction for different kinds and amounts of absorbing material. The principle of geometrical acoustics is utilized to Peform the simulation efficiently and accurately. The noise levels of the inside and outside of running car body are measured to find the noise level reduction. The average noise level reduction of 8 ㏈ has been attained. It has been shown that the simulated results are comparable to the measured ones.

• 대한안전경영과학회지
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• 제17권4호
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• pp.97-103
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• 2015

The people who are in the noise factory are difficult to hear and recognize about fire and to evacuate quickly when a fire occurs. This study was conducted to analyze workplace's background noise of 31 factories in Incheon and to know the workplace noise level comparing to fire alarm sound level. The measured average noise level was 96.8dB(A). Noise level of measured result was exceeded as 6.8dB(A) comparing to NFSC (National Fire Safety Code) noise level of 90dB. NFPA suggests that when background noise exceeds 85dB or more than that, other methods should be considered to know alarm sound. Also fire alarm sound should exceed more than 15dB(A) comparing to background noise level. Therefore it was concluded that the design of the fire alarm systems should not be applied to the workplace without considering background noise and it needs to be improved with regulations and the systems.

• 한국소음진동공학회논문집
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• 제26권5호
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• pp.616-624
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• 2016

Design of shelter system requires consideration of noise at operators’ positions, because noise can injure person’s health. That is why studies which analyze and predict noise at operator’s positions is essential. To analyze noise sources of shelter system, this study measured noise of each equipment and obtained new equations by comparing the measured noise data and the equation which is relation noise and distance. The new equations predict noise level at operators’ positions. Actran analysis is performed to obtain noise level at operators’ positions too. At last, the noise level at operators’ positions measured in real shelter system is compared with the noise level predicted the new equations and Actran analysis.

• 한국건축친환경설비학회 논문집
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• 제12권6호
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• pp.641-654
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• 2018

Elevator noise in apartment houses is one of the factors which prevent the residents from quiet and comfortable life. The elevator noise measurement method [KS F ISO 16032] is introduced from the matching ISO standard, however, it has problems in the application to the actual measurement. To visualize the problems, measurements in an apartment house are conducted, which has been suffering from the elevator noise for a long time. The measurement itself is extremely difficult due to the low sound pressure level of elevator, which is lower than 35 dB (A), and the even higher background noise level. However the vibration levels measured at the same time are relatively less disturbing As a result of vibration measurement, it was found that the vibration is clearly measured on the wall, and presents a high correlation coefficient of over 0.8 with the noise levels measured This shows that the vibration level measured on the elevator walls may be rather reliable numbers than the elevator noise levels in the actual noisy condition of elevator halls and the vicinity.

• 한국소음진동공학회논문집
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• 제11권4호
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• pp.58-64
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• 2001

Sound absorbing materials are applied to the exposed surfaces of curvet subway tunnel for the reduction of curving noise level. Before the treatment, acoustical engineering simulation is performed to predict the noise level reduction for different kinds and amounts of absorbing material. The principle of geometrical acoustics is utilized to perform the simulation efficiently and accurately. The noise bevels of the inside and outside of running car body are measured to find the noise level reduction. The average noise level reduction of 8 dB has been attained. It has been shown that the simulated results are comparable to the measured ones.

• 한국소음진동공학회논문집
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• 제14권11호
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• pp.1123-1128
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• 2004

An experimental study on firing noise of K2 rifle was performed. Firing noises of K2 rifle were measured at close distance to rifle. Firing noise of K2 rifle which made in Korea, has not measured before. The measurement of firing noise at close distance is not simple, because the amplitude of firing noise is much bigger than the measuring limit of ordinary sound level meter even though it uses a signal attenuator. The measurement of firing noise at close distance is necessary for noise source positioning and for obtaining the sound power of K2 rifle. By this experimental study, the firing noise levels of K2 rifle at different positions are obtained and these data can be used to Predict the sound pressure level at any distance from muzzle of the rifle. Also these data can be used to calculate the threshold shift of gunner's ear.