• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.411-414
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• 1999

Insertion loss of partially Inclined noise harrier Is studied by using multiple diffraction theory. The diffractions occurred at the top as well as partially folded point are included based on Kouyoumjian and Pathak's method (Procd. IEEE, Vol. 62, 1974). Scaled-down model of noise barrier is studied in anechoic rooom. It is shown that the theoretical results generally represents the average values of experimental results, while there are many oscillations in experimental results.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.7
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• pp.570-576
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• 2003

Noise harriet Is used for noise reduction method of traffic noise. The length and the total cost of that are increased In this national area. But. a maintenance management of noise barrier is not systematic. and the guideline of that is not prepared for maintenance manual. The situations of existed installation and management of noise barriers Installed at 3.619 positions were investigated by questionnarie and direct field survey. And comparisons with foreign management guideline of noise harrier were carried out. The results show that the improvement methods of maintenance management system such as practical checklist and required Items for management of noise barrier were suggested.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.1099-1103
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• 2002

With rapidly industrial development, a railway has become of a main traffic means. But, the railway noise has caused much annoyance for the residents living nearby railway tracks. Therefore, in our country, for established of quite dwelling environment. execute regulation standard of railway noise from January 1. 2000. Efficiency soundproofing measures, however, are very difficult because of the lack of basic data and insufficiency of the existing research. In this point. this study attempts to survey the vertical sound pressure level of railway noise in by existence of noise harrier And this study intends to get the basic data for establishment of a efficient noise barrier about railway noise.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.8
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• pp.619-625
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• 2003

A successful design approach for noise barriers should be multidisciplinary because noise reduction goals influence both acoustical and non-acoustical considerations, such as maintenance, safety, physical construction, cost, and visual impact. These various barrier design options are closely related with barrier dimensions. In this study, we have proposed an optimal design method of noise barriers using simulated annealing algorithm, providing a harrier having the smallest dimension and achieving the specified noise reduction at a receiver region exposed to the noise due to Industry and infrastructure, to help a successful barrier design.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.6
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• pp.413-419
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• 2002

Noise barriers are widely used to reduce the sound level propagating from highways, railways or factories to residential areas. The reduced noise level at a receiver point is then determined by the diffracted waves around the edge of the barrier as well as by the transmitted waves through the barrier. 1'or proper usage, many studies either theoretical or experimental have been made with the objective of precisely Predicting the acoustic field and improving the noise attenuating properties of barriers. In this study. a simple scattering model. a line acoustic source scattered by an infinite cylinder, is introduced to simply Investigate the sound attenuation efficiency of a sound-resonating barrier. From this model study, it is observed that the sound-resonating harrier can be used as a good sound-shielding element especially for the pure-tone noise generated from the transformer. Large sound-attenuation is achieved by applying the sound-resonating barrier to the large transformers in a substation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.135-138
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• 2005

On the basis of theoretical studies on the effect of the cylinders attached to semi-infinite screens, the effect of the tangential sound power-transport along the cylindrical top section of noise barriers is studied. Four types of acoustical mechanism between the surface of the cylinder and the adjacent air particles are investigated, namely Z $\rightarrow$ $\infty$, Z $\rightarrow$ pc, Z $\rightarrow$ 0 and actively controlled surface sound field. In active control case the sound power parallel to the surface of the attached cylinder is minimized by means of a secondary sound field, which is generated from a part of the attached cylinder. In each case the change in the acoustical shadow zone was shown and compared. The numerical study shows the possibility of deflecting the incident sound by minimizing the acoustical surface impedance of the upper sections.