• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.505-509
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• 2008

This paper studied the efficient noise prediction method for new apartment house near the road traffic noise. Three noise prediction software were compared by each prediction noise level using the simple model which is included the road, soundproofing wall and building. Two foreign national calculation models(RLS-90 and NMPB) were verified by comparison of measured sound level. Frequency of sound level was predicted by NMPB and compared by measured data. The sphere of noise source and facade reflection were proposed to accurate predict the road traffic noise in new apartment house.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.4
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• pp.425-432
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• 2009

Recently, reduction of road traffic noise in residential buildings has become one of the most important subjects. To reduce the road traffic noise, noise impact assessment by the road traffic prediction model is required before building construction. For reasonable road traffic noise prediction, it is required to analysis of various factors in road traffic prediction models. This paper was studied the road traffic noise propagation factors such as distance from road to building, receiver height, alignment angle of building and reflection coefficient of the building facade by two calculation models, RLS-90 and CRTN. The result showed that noise reduction was generally higher at bottom stories by ground absorption effect. The reflection coefficient of the building facade was affect of additional sound pressure level by facade reflecting. And alignment angle of building at $90^{\circ}$ was performed effective noise reduction better than $0^{\circ}$.

• The Journal of the Acoustical Society of Korea
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• v.16 no.1E
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• pp.29-34
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• 1997

Numerical prediction of aerodynamic noise radiated by subsonic rotors are carried out. A computer program has been developed which incorporates both the discrete frequency noise as well as the broadband noise arising from the ingestion of turbulence. Acoustic analogy is used in conjunction with Homicz's formulation of turbulence ingestion noise. Formulation 1A of Farassat is used to enhance the numerical analysis performance of Ffowcs-Williams Hawkings equation by eliminating the numericla time differentiation. Homicz's trubulence ingestion noise prediction technique is used to understand the characteristics of broadband noise radiated by isotropic trubulence in gestion. Numerical predictions are carried out for a number of rotor configurations and compared with experimental data. Monopole consideration of transonic rotor agrees well with both the experimental data and the linear theory. Noise radiation characteristics of rotor at lifting hover are investigated utilizing simple blade loading obtained by thin wing section theory. By incorporating discrete noise prediction of steady loading with broadband spectrum, much better agreement with experimental data is obtained in the low frequency region. The contributions from different noise mechanisms can also be analyzed through this method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.477-478
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• 2010

It was in the mid-1980s when the shipboard noise analysis was introduced to the Korean shipbuilding industry. Since then through the continued efforts of the industries in the last decades, native computational codes dedicated to the shipboard noise prediction have been developed based on empirical formula and/or sophisticated theories such as SEA and PFM. This paper addresses some problems in dealing with predicting shipboard noise and the way how to overcome the uncertainties in the prediction.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.6
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• pp.555-561
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• 2010

Predicted noise level has been used to assess the annoyance response since noise map was generalized and being the normal method to assess the environmental noise. Unfortunately using predicted noise level to derive the annoyance prediction curve caused some problems. The data have to be grouped manually to use the annoyance prediction curve. The aim of this paper is to propose the method to handle the predicted noise level and the survey data for annoyance prediction curve. This paper used the percentage of persons annoyed(%A) and the percentage of persons highly annoyed as the descriptor of noise annoyance in a population. The logistic regression method was used for deriving annoyance prediction curve. It is concluded that the method of dichotomizing data and logistic regression was suitable to handle the predicted noise level and survey data.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.302-309
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• 2009

Nowadays, the construction sites are growing in city every year, so complaints for construction noise have increased more and more. To analyze this noise scientifically, construction noise prediction program was developed in 1998 and 2005 but it is too difficult to apply program in field because there is few soundproof facilities and it can't understand the coordinate system and so on. The aim of this study is to develop noise prediction program to apply in construction sites. For this, the problems of existing program was analyzed and survey was performed to get requestion of field overseer and upgraded program. To get reliability of program, it was compared with sound measurement value in field. As a result, construction sound prediction program have various soundproof facilities data than existing program. It can also analyze multi receiver point at the same time for several construction machinery. Most of all, it is more powerful to set receiver or source in the axis of X, Y, Z. so program user can make use of it easily. An average of difference is -0.9$\sim$1.8dB.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.4
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• pp.409-417
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• 2009

Nowadays, the construction sites are growing in city every year, so complaints for construction noise have increased more and more. To analyze this noise scientifically, construction noise prediction program was developed in 1998 and 2005 but it is too difficult to apply program in field because there is few soundproof facilities and it can't understand the coordinate system and so on. The aim of this study is to develop noise prediction program to apply in construction sites. For this, the problems of existing program was analyzed and survey was performed to get requestion of field overseer and upgraded program. To get reliability of program, it was compared with sound measurement value in field. As a result, construction sound prediction program have various soundproof facilities data than existing program. It can also analyze multi receiver point at the same time for several construction machinery. Most of all, it is more powerful to set receiver or source in the axis of X, Y, Z. so program user can make use of it easily. An average of difference is -0.9~1.8 dB.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.55-58
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• 2005

This study was Performed to grasp of the problem and improvement in traffic noise environmental impact assessment(EIA). National institute of environmental research(NIER) traffic noise prediction model is in general use in internal EIA. In this study, NIER noise prediction model need to improve in that the predicted results lower than the measured results. The other predict model(KLC KEI) is more accurate. Also the volume and speed of traffic is need to standardize in traffic noise prediction.

• The Journal of the Acoustical Society of Korea
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• v.14 no.6
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• pp.48-53
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• 1995

A considerable number of methods are available for predicting traffic noise levels of road networks where sound is freely propagating. But surrounding buildings reflect back sound to the road and sound energy is increased by these reflectors. Therefore, this study was focussed on the establishment of the prediction method of road traffic noise under reflective conditions. This prediction method was developed by establishing prediction formulas of noise level such as $L_{10},\;L_{50},\;L_{90}\;and\;L_{eq}$. The sound energy density was employed to establish prediction formulas in terms of independent variables. The validity of the proposed prediction formulas was been confirmed by applying them to actually measured parameters of road traffic noise and noise level data. On the whole, the agreement between measured and predicted noise levels appeared to be satisfactory. The conclusion might be reached that the method developed in this study could be used to predict road traffic noise under reflective conditions.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1990.10a
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• pp.53-58
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• 1990

The use of spreadsheet packages for solving noise control problems has been cited by several authors, eg Saha[1] and Thornton[2]. The effectiveness of using spreadsheet packages compared with the traditional computer programs written in high level languages was demonstrated when applied to relatively simple problems, such as the selection of hearing protectors or the prediction of noise equation which includes logarithmic additions at most represents the physics of the problem. The simplicity of the governing equation together with the requirement to handle a vast amount of data are considered to be the major reasons for noise control engineers to use spreadsheet packages. Although shipboard noise prediction seems to be very complicated, the calculation procedure itself is, in essence, identical especially true for prediction methods based on empirical formulae[3,4], ie the procedure that consists of the three basic elements, ie source, path and receiver. This paper discusses the application of spreadsheet package LOTUS 1-2-3 to shipboard noise prediction problems. A utility program of the package is written using macro functions and is shown to be especially useful for noise control engineers who are unfamiliar with spreadsheet packages. In addition, a new type of empirical formula, to estimate structureborne noise transmission loss, is proposed.