• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.3
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• pp.214-223
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• 2004

This study aim to find an appropriate window for classrooms to provide proper sound insulation against aircraft noise and to achieve this goal, measurements were taken of the sound insulation performance of windows with various thicknesses of inner air space and sound absorption materials in the inner air spaces. As a result of this study the improvement of the sound insulation performance of windows(single, double and triple window) was shown through the analysis and the measuring of windows with these characteristics. These results may be applied to the manufacture of window frames and provide basic data for the improvement of the sound insulation performance of windows.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.7 s.100
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• pp.859-864
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• 2005

Noise map is a presentation of existing data or predicted noise situation in terms of noise indicator. However, it has shortcoming for assessing the number of people exposed, or the number of dwellings affected to any relevant limit values of noise level in certain areas. In this study, so called over-ride value noise mapping is Proposed to make up for the shortcoming by using over-ride function of object-oriented programming and it is to show the guard of the area where it is satisfied the standard of option, or it is not satisfactory. Over-ride value noise map data is combined with topography layer, population and house statistics, and GIS space statistical analysis. The over-ride value noise mapping can also be applied to make the road traffic noise map, the railroad noise map, the aircraft noise map, and the industrial site noise map. This can express noise damage information more exactly.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.710-717
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• 2003

This study aim to find an appropriate window for class rooms to provide proper sound insulation against aircraft noise and to achieve this, measurements were taken of the sound insulation performance of windows with varying thicknesses of inner air space and sound absorption materials in the inner air spaces. As a result of (his study the improvement of the sound insulation performance of windows(single , double and triple window) has been shown through the analysis and the measuring of windows with these characteristics. These results may be applied to the manufacture of window frames and provide data lot the improvement of the sound insulation performance of windows.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.1
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• pp.62-69
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• 2020

This study intended to evaluate noise level of dental handpieces and the effects of noise cancelling devices. An ear model was designed to measure the level of the noise delivered to the inner ear during dental handpiece operation. The level of noise was measured in various conditions using the ear model and the portable noise meter. Noise level was measured again after applying of 4 different noise cancelling devices to the model ear. The noise level of dental handpieces was 82.5 - 84.4 dB. When 4 types of noise canceling devices were applied, the noise level reduced to 67.4 - 73.8 dB. All 4 devices had statistically significant effect in reducing the noise of the handpiece. Considering the intensity and exposure time, noise in dental clinics can cause hearing damage to dentists. For protection from the risk of occupational hearing damages, noise canceling devices can be recommended.

• Journal of Environmental Policy
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• v.6 no.1
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• pp.111-132
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• 2007

The traffic noise of Busan, the second largest city in Korea, is polluting the area. Noise map is a map that shows data on an existing or predicted noise condition in terms of a noise indicator, breaches of a limit value, the number of dwellings exposed to certain values of a noise indicator in a certain area, or on cost-benefit ratios or other economic data on mitigation methods or scenarios with Geographic Information System. With noise map, the effect of traffic noise and the efficiency of city development plan are exactly estimated. So making systematic counteroffer is possible with it. This study is aimed to the construction of basis for noise map construction method for domestic use and the area focus is Busan.

• Journal of Korean Society of Transportation
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• v.35 no.4
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• pp.292-306
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• 2017

Traffic noise cost can be assessed either by the damage cost approach or by the avoidance cost method. This paper provides an overview of pertinent studies of these two approaches and shows that the damage cost approach is more universal and reliable than the avoidance cost counterpart. This study then investigated three sub-components to address the damage cost framework. First of all, unit value per person exposed to noise per year was calculated. Secondly, the area exposed to noise was determined using noise prediction equation. Thirdly, the number of people affected by noise was computed by multiplying the number of people exposed to noise with the percentage of people affected by noise. This paper also suggested a simplified equation that represents the relationship between damage costs and noise levels. Finally, the benefits of noise reduction derived from the damage cost method and those from the avoidance cost approach were compared and discussed.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.22 no.2
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• pp.149-155
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• 2012

Objectives: 이 논문의 목적은 한 사업장에서 수십 년 동안 진행된 소음감소계획이 실제적이고, 경제적인 것을 증명하고 이를 바탕으로 소음의 공학적 개선방법과 효과적인 실행을 위한 실제 작동 가능한 모델을 제시하는 것이다. Methods: 1967년도에 설립된 다국적 전자회사에서 1987년부터 2002년까지 실행된 각종 소음 감소 노력, 요소, 프로그램을 분석하고 이 기간 동안 소음감소가 어떻게 실제로 일어났는지 분석하였다. 특히 회사가 다른 여러 가지 노력을 한 후에도 실질적 효과를 기대하기 어려워 공학적 개선과 같이 도입한 Action Learning Team (ALT) 활동에 초점을 두고 개선 효과를 파악하였다. Results: 실제 소음의 감소노력은 산업안전보건법의 변화에 따라 여러 가지 형태로 실행되었다. 주된 효과는 ALT활동이 있고 나서 이루어졌는데 평균 소음 노출수준이 86.9 dBA에서 79.8 dBA로 현저히 감소하였으며 소음 지역 (85dBA 이상 )도 10개 지역에서 3개 지역으로 70% 감소하였다. ALT 활동의 결과로 나타난 7개 지역의 소음 감소를 위해 투입된 총 비용이 6,767 달러였다. ALT 활동을 처음 시작한 첫해에 소음 감소지역을 줄임으로써 이 지역의 근로자가 청력검사를 받지 않아서 초기 396명의 근로자가 청력검사를 받던 것을 활동 후 130명만 받아 266명의 근로자가 청력검사를 받지 않아도 되어 청력검사 비용이 6,650 달러 절약되었다. 따라서 장기간으로 보면 매우 비용효과적인 방법으로 증명되었다. Conclusions: 실제 소음감소가 현저히 일어나고, 비용효과적인 소음 감소가 일어나려면 기기 설비 공정담당자가 소음감소의 중요성을 잘 알고, 그 기법을 숙지하고 있어야 하며, 실제 활동을 할 수 있도록 관리자 층의 권한을 위임 받아 활동할 수 있어야 한다. 이 논문에서는 공학적 개선 태스크포스팀을 운영하여 ALT활동을 하였을 때 실제적이고, 비용효과적인 소음 감소를 증명하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.5 s.108
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• pp.451-460
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• 2006

We have designed local exposure systems for long-time mice experiments in PCS and cellular frequency band(PCS: 1,762.5 MHz, cellular: 848.5 MHz). The fabricated systems are local exposure systems of carousel type, and 40 mice can be exposed at a time. In order not to give extra stress to the mice ender experiment, the systems were fabricated to meet the environmental conditions such as illumination, ventilation, noise etc. SAR measurement was performed using a temperature probe. Measurements at 3 points in the head of mouse cadaver and solid phantom were made, and it has been confirmed that the measurement results are in good agreement with the simulation results in the real exposure environment. The exposure systems are currently used for long-term mice experiments.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.3
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• pp.264-274
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• 2012

Evaluation on the environmental noise is carried out by surveying subjective response of residents with physical measurement of noise during long period in field. Particularly field survey is used to make regulations from the analysis on how many people are annoyed for specific noise level, and laboratory test used to analyze the relationship between physical parameters of noise and subjective responses. In the laboratory controlling the variables is easy but the results could be biased because the condition in room would be different with field. Most of all noise exposure time is considered to be different with real situation, and this study aimed to evaluate the subjective response by exposure time of transportation noise, by applying three kinds of variable how much they give effects on the annoyance as the exposure time is operating condition, windows type and sound level. As a result there was somewhat difference between operating type and annoyance, which is caused by the sound characteristics operated in different condition. However the window type didn't give much effect to the annoyance as much as sound type. This means that the subjective response could give similar result by exposure time even for different window types. Most of all, the main factor affecting subjective response is considered to be the sound level and the exposure time.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.6_spc
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• pp.729-735
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• 2016

According to the survey for working environment of the cashiers in highway tollbooths, workers replied that noise was the most harmful substances next to air pollutant in the tollbooth. Researches on the noise levels exposed to cashiers in the highway tollbooth scarcely have been performed. Therefore, the aim of this study was to acquire baseline data to prevent health impairments of the cashiers by evaluating noise level exposed to them. Noise dosimeters were used for monitoring workers' noise exposure level in the tollbooths at 8 different highway tollgates. The noise levels of tollbooths did not exceed noise exposure limit of the ministry of labor, 90 dB(A). The average TWA inside of the tollbooths was 55.4 dB(A) and the average TWA outside of tollbooths was 58.3 dB(A). The average TWA outside of tollbooths was slightly higher than that of inside of tollbooths. However, the significance probability(p-value) was 0.255 which means statistically not significant. The noise levels inside and outside of tollbooth were statistically significant to both mean traffic volume per day and traffic volume of passenger car.