• 한국소음진동공학회논문집
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• 제27권2호
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• pp.243-250
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• 2017

In this study, single number rating methods of sound absorption coefficients are discussed. After that the sound absorption performance of noise barriers which are classified by Korea Standard are analyzed according to several standards. The existing rating methods such as NRC (noise reduction coefficient), SAA (sound absorption average) or ${\alpha}_w$ (weighted sound absorption coefficient) from ASTM C423, KS F 3505 and ISO 11654 are introduced. The sound absorption performance of noise barrier is evaluated to compare NRC and ${\alpha}_w$ value. When the value is over 0.6 there are large variance between NRC and ${\alpha}_w$ value. As results, it is needed to unify single number rating methods of sound absorption coefficients for Korean standards on sound absorbing materials.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.612-615
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• 2006

In this study, we compared and analyzed the floor impact noise insulation performance produced by the rating methods. The rating methods are using reversed A-weighting curve, A-weighted sound pressure levels(dB(A)). The results of this study are(1)dB(A) by the specified frequency is 0.5dB(A) at light weight and 2.5dB(A) at heavy weight upper than all pass dB(A)(2)the rating using reversed A-weighting curve is 5dB lower than dB(A)(3)the number of rating using reversed A-weighting curve mainly depends on impact noise pressure level of 63Hz in heavy weight but dB(A) does not.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.291-294
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• 2005

In this study, we compared and analyzed the floor impact sound insulation performance produced by the rating methods. The rating methods are using reversed A-weighting curve, A-weighted sound pressure levels and arithmetic average. On-site floor impact sound pressure levels of living room and room are measured. The results of this study are 1)the rating using reversed A-weighting curve for heavy-weight impact sound's standard deviation is lower than that of light-weight impact sound, 2)the number of rating using A-weighted sound pressure levels and arithmetic average is larger than that of using reversed A-weighting curve, and 3)the number of rating using reversed A-weighting curve mainly depends on impact sound pressure level of 63Hz in heavy-weight impact sound.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.631-635
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• 2006

In this study, simplified methods on measurement and evaluation of heavy-wight impact sound was proposed due to provide easy quality control method to construction engineers. The simplified methods include using of rubber impact ball instead of bang machine, reduced number of measuring and impact positions which is prescribed as over 4 points, using of hand-held sound level meter as a frequency analyser and prediction equation for $L_{i.Fmax.AW}$, single number rating, using $L_{Amax}$, and $L_{Lmax}$ at each frequency band. The results showed that a method of boundary driving and boundary measuring is the most similar to the current rating method.

• 소음진동
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• 제9권5호
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• pp.899-905
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• 1999

Construction equipment noise has caused much annoyance for a number of dwellers in nearby construction field and has become a very serious issure in our living environment. Therefore, in our country, a practical solution and a better method of reducing construction equipment noise are highly required in construction field. Practical solutions for the construction equipment noise, however, are very difficult because of the poorness of basic data and insufficiency of the existing research. Especially, in order to establish the sound insulation plan about pilling works noise with high sound pressure level and impactive, a real situation of sound characteristics about the noise of pilling works in foundation work demands more detail investigation. In this point, this study attempts to survey the characteristics of attenuation and propagation of construction equipment noise in pilling work using SIP(soil-cement injected precast pile) method with casing. And this study intends to get the basic data for establishment of a standard about construction noise.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.864-869
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• 2003

KS F 2808 was revised in 2000 and KS F 2862-1 was newly established in 2001. Thus Related Korean Industrial Standard such as KS F 4724, KS F 4735, KS F 4736 should be revised according to KS F 2808 and KS F 28612-1. This study aims to elicit the new rating numbers such as R$\sub$w/, R$\sub$w/＋C, R$\sub$w/＋C$\sub$tr/, L$\sub$m/ defined in KS F 2862-1 instead of exiting rating number; transmission loss of 500Hz.

• 수산해양교육연구
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• 제22권2호
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• pp.218-230
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• 2010

This study was conducted to determine the effect of the noise level on the boarding environment in a stern trawl ship, KAYA(GT: 1,737 tons, Pukyong National University). We measured the noise level at a working, an accommodation and a teaching area, and an engine space on January 9, 2010 while the KAYA was sailing on a liner sea route. At the working area, the ranges of the noise rating number(NRN) and the NRN determination frequency(FNRN) were from 44 to 73 and from 1000 to 2000Hz, respectively. The results were generally satisfied the criteria of the International Maritime Organization(IMO). The noise level at the area, except the radio room(w2), was exceeded the criteria(50dB(A)) for the efficient studying and working. The noise level at the engine control room and the machine workshop was respectively exceeded 1.2dB and 9.5dB than the criteria caused the conversation disturbance (70dB(A)). At the accommodation, NRN and FNRN were from 49 to 54 and from 1000 to 4000Hz, respectively. The noise level was below the criteria of IMO, but above 40dB(A) caused the sleep disturbance. At the teaching area, NRN and FNRN were from 44 to 63 and from 500 to 2000Hz, respectively. The noise level was exceeded than the criteria(50dB(A)) for the efficient studying. At the engine space, NRN and FNRN were from 95 to 100 and from 2000 to 4000Hz, respectively. The noise level was above the criteria of IMO(90dB(A)) for the residence, while it was not exceeded 110dB(A) for the transient.

• 대한조선학회논문집
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• 제47권4호
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• pp.589-597
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• 2010

The indoor noise of the naval vessel is very important considering hearing protection, improvement of working environment and easily communication between crews. When the environment of the naval vessel suffering from the noise is considered, it is very important to be quiet in the living area where the crews have a rest sufficiently. In addition, the noise of the working area should be reduced in order to increase working efficiency. Therefore, in this research, the satisfactions about the indoor noise are survey for crews working in a naval vessel. Through this survey, the relationship between the indoor noise and crew's satisfaction about it can be found. As a result, the limit of sound pressure level which almost all crew can be satisfied with the indoor noise about their living and working area is suggested base on the survey in this research.

• Safety and Health at Work
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• 제2권4호
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• pp.336-347
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• 2011

Objectives: In Korea, an average of 258 workers claim compensation for their noise-induced hearing loss (NIHL) on an annual basis. Indeed, hearing disorder ranks first in the number of diagnoses made by occupational medical check-ups. Against this backdrop, this study analyzed the impact of 19 types of noise-generating machines and equipment on the sound pressure levels in workplaces and NIHL occurrence based on a 2009 national survey on work environments. Methods: Through this analysis, a series of statistical models were built to determine posterior probabilities for each worksite with an aim to present risk ratings for noise levels at work. Results: It was found that air compressors and grinding machines came in first and second, respectively in the number of installed noise-generating machines and equipment. However, there was no direct relationship between workplace noise and NIHL among workers since noise-control equipment and protective gear had been in place. By building a logistic regression model and neural network, statistical models were set to identify the influence of the noise-generating machines and equipment on workplace noise levels and NIHL occurrence. Conclusion: This study offered NIHL prevention measures which are fit for the worksites in each risk grade.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2002년도 춘계학술대회논문집
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• pp.209-212
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• 2002

This article introduce Comfort Class V released by Dnv The Class has an objective of classifying ships by noise and vibration levees. It is apparent that noise criteria listed in the Class can not be satisfied without special efforts to enhance sound insulation performance in cabins. Accordingly, panel makers should develope panels which have very high sound insulation performance enough to satisfy the criteria. Also, due to large difference of sound insulation performance between cabin and laboratory, it is necessary that ship yards should improve the method for installing cabins.