• Proceedings of the Korean Society of Computer Information Conference
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• 2014.01a
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• pp.425-426
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• 2014

충격소음(Impulse Noise) 측정 시 지그(Ear Simulator)가 자체적으로 음압측정에 미치는 영향을 확인하기 위해 지그를 이용하여 실내에서 충격소음을 측정하였다. 측정의 신뢰성과 정확성을 확보하기 위해 마이크로폰과 지그에서 동일조건에서 동시에 데이터를 수집하였다. 추가로 헤드&토르소에서 실험을 실시하였다. 최대음압레벨과 1/3옥타브 밴드 결과를 비교분석함으로써 측정 방법에 따른 차이점을 발견하였다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.12 no.3 s.26
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• pp.193-199
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• 2006

The noise levels on board ship recognized at Europe in the early 1970s and the noise regulations on the ship began to put in a statutory form. After that, in 1982 'International Code on Noise Levels on Board Ships' adopted by IMO and it became a standards to the newly built ship and it remains up to recently. Especially, the ship engine room, which have huge main engine and various kinds of subsidiary machines, is under an extremely loud condition and so the worker who works in it is easy to lose his hearing. Recently, each nation regulates the allowable noise exposure time by law to protect the industrial employee from the occupational hardness of hearing. In our country, the allowable noise exposure time is regulated by the labor. standard law but the international provisions regulated by IMO have been applied in case of the ship engine room. In this paper, the cabin's noise levels of cargo-passenger ships plies south-west coast line were investigated.

• Proceedings of KOSOMES biannual meeting
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• 2006.05a
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• pp.207-212
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• 2006

The noise levels on board ship recognized at Europe in the early 1970s and the noise regulations on board ship began to put in a statutory form. After that, in 1982 "International Code on Noise Levels on Board Ships" adopted by IMO and it became standard to the newly built ship and remain so to this day. Especially, the ship engine room, which have huge main engine and various kinds of subsidiary machines, is under an extremely loud condition and so the worker who works in it is easy to lose his hearing. Recently, each nation regulates the allowable noise exposure time by law to protect the industrial employee from the occupational hardness of hearing. In our country, the allowable noise exposure time is regulated by the labor standard law but the international provisions regulated by IMO have been applied in case of the ship engine room. In this paper, the cabin's noise levels of cargo-passenger ships plies south-west coast line were investigated.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.431-434
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• 2014

Wind turbine industry is the most developing field among other renewable energy industry. As expanding wind farms, noise is the big problem to solve. This study is about wind turbine noise measuring method based on IEC 61400-11. Sound pressure levels, 1/3-octave band levels, and low frequency sound pressure levels of a 3 MW wind turbine were measured and analyzed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1459-1464
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• 2006

In the previous studies on railway noise analysis, the main purpose of noise analysis is concerned with the reduction of A-weighted sound pressure level in order to satisfy noise regulations. However, more important facts on noise reduction are the subjective feelings of the human being on noise because people might be annoyed from the noise caused by train. In this paper, railway noise from different type of train are compared using the calculation of sound quality metrics with using strength related method that is calculation of A-weighted sound pressure level.

• The Journal of the Acoustical Society of Korea
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• v.22 no.3
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• pp.233-241
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• 2003

It is statistically analyzed the underwater ambient noise measured at 13 sites less than 200 m deep in the shallow water surrounding the Korean Peninsula for 9 yews from 1990 to 1998 in various environmental conditions. Frequency spectra were obtained with the 1/3-octave band center frequencies from 25㎐ to 20 ㎑. The analyzed shallow water noise spectra were some different from the deep water blown as the Wenz spectra. We could know that the ambient noise level shows higher than it in same condition by effect of various ship activity and the coastal noise, surface waves, and so on. As a result, we produced the coastal ambient noise spectra curve based on these results in shore of the Korea Peninsula.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.386.2-386
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• 2002

This paper reports the performance and the Algorithm of an 1/3-octave band spectrum control system. The system is developed to provide various required spectrums in a high intensity acoustic chamber. The required spectrums, which usually comes from launch vehicle specification, starts from 25㎐ band and ends 10,000㎐. Short settling time is required to guarantee the safety of test objects and reduce the amount of operating gas. (omitted)

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.857-860
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• 2003

We introduced the basic direction of revision for KS F 2805 (method for measurement of sound absorption coefficient in a reverberation room). It is fundamentally equal to ISO 354 (measurement of sound absorption in a reverberation room) which was state of ISO/FDIS 354. Two main points were strongly reviewed. First, the sound absorption coefficient values for Type J test specimen mounting was investigated. Next, the reverberation time difference between the conventional method and new additional one, impulse response method were compared.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.216-224
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• 2014

층간소음의 대부분의 원인이 아이들 뛰거나 발걸음으로 나타나고 있어 층간소음 저감을 위한 선행 연구로 층간소음의 주요 충격원인 보행 행위에 대한 정밀한 연구가 필요하다. 성인 보행 충격력과 그에 따른 바닥충격음을 계측하여 보행하중이 바닥충격음에 영향을 주는 요소를 분석하였다. 보행하중 중 발 뒤꿈치 충격력은 전체 충격하중을 주파수 특성을 대변할 수 있는 임펄스 형태의 하중으로 충격력은 뱅머신 또는 고무공보다 낮지만 1 차 영점(First zero)이 80Hz 정도로 높아 유효 가진 주파수 대역이 표준 중량충격원 보다 높았다. 구조물과 수음실의 고유모드 특성으로 인해 외부 충격에 대한 구조체 진동 및 음압의 공진 현상이 발생되기 때문에 공진 성분이 포함되는 바닥충격음 레벨은 순수 충격력 특성인 보행 또는 표준 중량충격원의 옥타브 밴드 충격력 폭로레벨과는 전혀 다른 주파수 특성을 나타내었다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.818-821
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• 2005

The sound measurement procedures of IEC 61400-11 are applied to field test and evaluation of noise emission from 1.5 MW wind turbine generator (WTG) at Yongdang and 660 kW WTG at Hangwon in Jeju Island. Apparent sound power level, wind speed dependence and third-octave band levels are evaluated for both of WTGs. 1.5 MW WTG at Yongdang is found to emit lower sound power than 660 kW one at Hangwon, which seems to be due to lower rotating speed of the rotor of WTG at Yongdang. Equivalent continuous sound pressure levels (ECSPL) of 660 kW WTG at Hangwon vary more widely with wind speed than those of 1.5 MW WTG at Yongdang. The reason for this is believed to be the fixed blade rotating speed of WTG at Yongdang. One-third octave band analysis of the measured data show that the band components around 400-500 Hz are dominant for 1.5 MW WTG at Yongdang and those around 1K Hz are dominant for 660 kW WTG at Hangwon.