• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.8
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• pp.581-588
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• 2002

Precise highway traffic noise simulation and reduction require the accurate data for sound power levels omitted by vehicles, varied to road surface, traffic speed, vehicle types and makers, different from countries to countries. In this study, we have elaboratively measured Korea highway traffic noise and parameters affecting noise levels at the nearside carriageway edge. From numerical simulation using the measured results for highway traffic noise, we propose not only two correction factors to enhance the accuracy of Korea highway traffic sound power estimation using ASJ Model-1998 but also its typical power spectrum according to road surface type. The measured and predicted highway traffic noise levels using the proposed sound power show little difference within 1 dB.

• Interaction and multiscale mechanics
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• v.3 no.4
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• pp.373-387
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• 2010

This study is intended to assess low frequency sound radiated from a viaduct under normal traffic. The bridge comprises steel box girders and wide cantilever decks on which vehicles pass. The low frequency sound and the acceleration response of the bridge under normal traffic are measured to investigate how bridge vibrations affect the low frequency sound observed near the bridge. Observations demonstrate that strong relationships exist between frequency characteristic of bridge's acceleration response and the sound pressure level of low frequency sound. A noteworthy point is that the dynamic feature of the sound pressure level is mostly affected by dynamic feature of the span locating near the observation point.

• Journal of Environmental Health Sciences
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• v.21 no.4
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• pp.56-62
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• 1995

Recently, the traffic noise around residences and schools has become a serious social problem with the increase of the amount of transportation. This study was performed to investigate the sound proof efficiency of windows for traffic noise. The results were as follows 1) The traffic noise in 19 sites among 22 sampling sites was higher value than 65 dB(A) being roadside environment standard level in the daytime when all windows were opened, while the noise in 22 sampling sites was transmitted below standard level when all windows were closed. 2) The transmission loss of sound level at single window and double windows were 10~25 dB(A) and 11~29 dB(A) respectively. 3) The transmission loss of sound level at sampled school with sound proof pannel was 7~8 dB (A), which was lower 2~7 dB(A) than the theoretical value of the influence assessment . 4) The construction cost of double windows was lower 28% even if include the cost of setting up air conditioner for the summer season and the power consuming cost for its operation than that of sound proof pannel for traffic noise. 5) The effect of transmission loss of windows was more influenced by airtight than materials of windows.

• Journal of Environmental Science International
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• v.12 no.1
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• pp.69-76
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• 2003

When houses or buildings are adjacent to roads, with no effective prevention of road traffic noise, neighbors are exposed to it. It is important to understand the properties of sound propagation before taking a countermeasure against road traffic noise. It is easy to estimate the properties of sound propagation without obstacles, but very difficult and complex to estimate them with ones. The purpose of this study is to present a useful tool that can estimate the properties of sound propagation. In the beginning of this study, we investigated the attenuation of road traffic noise with two pillar buildings, and presented practical approximate calculation method, and verified that through scale model. The outcomes from this study are as follows : (1) Over second reflection sound waves can be ignored. (2) Diffraction sound waves that happen when reflection sound and first diffraction wave are projected at the wedge of other building can be ignored.

• The Journal of the Acoustical Society of Korea
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• v.28 no.4
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• pp.356-362
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• 2009

In modern society, most people of the world are densely populated in cities so that the traffic sound has a very significant meaning. people tend to classify traffic sound as a noise pollution while they are likely to categorize most nature sound as positive. In this paper, we applied various forms of FFT filters into white noise belonged in nature sound to find frequency characteristics of white noise which preferred by people and confirm its correlation with nature sound. In addition, we conducted an analysis through the comparison of various traffic and nature sound waveforms and spectra. As a result of analysis, the traffic sound have characteristics which sound energy had concentrated on specific frequency bandwidth and point of time compared to nature sound. And we confirmed the fact that these characteristics had negative elements to which could affect to people. Lastly, by letting the subjects listen directly to both traffic and nature sound through brainwave experiment using electrode, the study measured the energy distribution of alpha waves and beta waves. As a result of experiments, it has been noted that urban sound created a noticeably larger amount of beta waves than nature sound; on the contrary, nature sound generated positive alpha waves. These results could directly confirm the negative effects of traffic sound and the positive effects of nature sound.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1272-1275
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• 2006

The A-weighting curve, very well explain the human perception for various frequency, is used to assess the traffic noise as well as the environmental noise. However, it does not reflect the annoyance perception appropriately because it assesses the noise at an A-weighted equivalent noise level of 1 kHz. In this study, we acquired the sound quality of traffic noise included various frequency and studied the human perception caused by change of frequency range.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.437-439
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• 2006

Actually, The present traffic accident detection system is subsisting limitation of accurate distinction under the crowded condition at intersection because the system defend upon mainly the image information at intersection and digital image processing techniques nearly all. To complement this insufficiency, this article aims to estimate the level of present technology and a realistic possibility by analyzing the acoustic characteristic of crash sound that we have to investigate for improvement of traffic accident detection rate at intersection. The skid sound of traffic accident is showed the special pattern at 1[kHz])${\sim}$3[kHz] bandwidth when vehicles are almost never operated in and around intersection. Also, the frequency bandwidth of vehicle crash sound is showed sound pressure difference oyer 30[dB] higher than when there is no occurrence of traffic accident below 500[Hz].

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.529-534
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• 2005

This study performed an physical analysis on the characteristics of urban environmental sound divided into three parts depending on their features. Object sounds were classified into traffic sound, waster sound and spatial sound. Traffice sound was selected because it is dominant sound in urban environment, and water sound is selected because it generally supplies pleasantness in contrast to traffic sound, Finally spatial sound was considered because it represents sound in various places of city having lots of behaviors and types of sound due to them. Physcal analysis was carried out using sound quality indices based on Zwicker's loudness, $L_{Aeq}$(equivalent noise level), Ln(percentile noise level) and other acoutical attributes applied to previous study. Through the analysis, this study aims to compare the acoustical characteristics of urban environmental sound and to provide fundamental data for the evaluation of urban environmental sound.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.1273-1279
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• 2001

Precise highway traffic noise simulation and reduction require the accurate data for sound power levels emitted by vehicles, varied to road surface, traffic speed, vehicle types and makers, different from countries to countries. In this study, we have elaboratively measured domestic highway traffic noise and parameters affecting noise levels at the nearside carriageway edge. From numerical simulation using the measured results for highway traffic noise, we propose not only two correction factors to enhance the accuracy of highway traffic sound power estimation using ASJ Model-1998 but also its typical power spectrum according to road surface type. The measured and predicted highway traffic noise levels using the proposed sound power shows little difference within 1 dB.

• Journal of Environmental Science International
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• v.16 no.7
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• pp.771-778
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• 2007

This study has been conducted to achieve the following objectives: First, in order to understand the horizontal propagation and attenuation characteristics for the railroad traffic noise, we selected areas within 100 meters away from the railroad and then selected Saemaul-ho and Mugoongwha-ho as the subjects for our experiment. In this way, we analyzed the horizontal propagation and attenuation characteristics for the traffic noise occurring in diversified areas. Second, in order to understand the vertical propagation and attenuation characteristics for the railroad traffic noise, we measured and analyzed the distributional characteristics of vertical sound pressure levels on each floor of multi-storied apartment buildings according to changes of traffic load and types, and the existence or nonexistence of soundproof walls. For the case of the railroad traffic noise, we also selected Samaul-ho and Mugoongwha-ho as the subjects for our experiment, and we measured and analyzed the different noise levels on each floor of multi-storied apartment buildings from the soundproof wall. The results of Horizontal propagation and attenuation characteristics for the railroad traffic noise are as follows: In cases of the flat land, cutting land, and bridge area, as distance increases, the sound pressure level steadily decreases. The sound pressure level for the bridge area is higher than that of the flat land with a measurement of $5.5{\sim}10.2\;dB(A)$. Vertical propagation and attenuation characteristics for the railroad traffic noise are as follows: The amount of sound pressure level decrease is $14.2{\sim}14.8\;dB(A)$ for Samaul-ho and $13.5{\sim}14.3\;dB(A)$ for Mugoongwha-ho when measuring the vertical sound pressure levels at heights lower than 4.5 m, which indicates a fairly large decrease. At 6 m, the amount of decrease is 8.6 dB(A) for Samaul-ho and 8.2 dB(A) for Mugoongwha-ho, which indicates a small decrease.