• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.1152-1155
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• 2007

Lately concerns about structure have been increased by advantages of floor impact noise, poilitical induction and changeability. Hence, Flat Plate Structure has been constructed increasingly. This study shows the comparison of the performance of sound insulation of Flat Plate Structure System and the existing Wall Structure. For this study, taking the same level organization of Daelim Architectural Environmental Research Center, I found the performance of sound insulation between the upper and lower floors about Wall Structure and Flat Plate Structure. Consequently, the performance of sound insulation between upper and lower floors of Flat Plate Structure was 3-5dB higher was approximately 3-5dB higher than one of Wall Structure. Especially, the performance of sound insulation on the upper floor was 1-3dB higher than on the lower floor. In addition, as the result of comparing radiation sound which radiates from the wall of lower floors with each structure system, Flat Plate Structure was about 4dB higher with Rw than Wall Structure. As we see totally, the performance of sound insulation of Flat Plate Structure is highter than one of the Wall Structure. It is 3-5dB higher and the main reason for this result depends on the existence of the wall which can radiate sound and nonexistence.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.671-674
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• 2006

Heavy-weight impact sounds generated by impact ball were classified according to the frequency characteristics on the equal loudness contours. Sound quality metrics such as Zwicker's loudness, sharpness, roughness of each classified impact sound were also measured. Loudness spectrum has been regarded as an indication of the characteristics difference of each classified impact sound. The adjectives in Korean expressing the sound quality characteristics of floor impact sounds were also investigated by adoptability and similarity tests. The group of the adjectives was used to evaluate the sound quality of floor impact sound by semantic differential test method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.1003-1008
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• 2004

In our life, we have used many digital appliances. They helped us to improve the quality of lift but sometimes gave us unsatisfactory result because they produce specific noise. Especially a vacuum cleaner produces a great deal of noise that is very annoying. So we need to study what sound metrics affect human sensibility. In this paper, we will study sound quality index for vacuum cleaner. The subjective evaluation of vacuum cleaner sound can be indicated to objective parameters by sound metrics of psychoacoustics. The artificial neural network can estimate the nonlinear characteristics of relation between subjective evaluation and sound metrics. We applied the artificial neural network to the development of sound quality index for vacuum sound.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.5 s.110
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• pp.537-543
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• 2006

The impact sound of the golf club is one of the major factors to purchase it. Sound quality metrics has been mostly developed for harmonic sounds. Sound quality evaluation techniques for the impact sound have been contrived in this study. Jury test, one of the typical subjective evaluation scheme, is carried out for evaluating the sound quality of 13 different golf drivers, which classification results are assumed to be correct answers. Conventional objective evaluation methods such as Zwicker loudness sensory pleasantness are calculated. Wavelet analysis and instantaneous loudness are applied in order to evaluate the sound quality of transient sounds, which scheme shows better correlation with the results from jury test.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.658-661
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• 2005

In many fire emergencies, the auditory fire alarm signals are very important to save the occupant's life. But as the sound insulation of building elements has been improved, it is more difficult for occupant to recognize the fire alarm signals when the audible fire alarm worked. This is the first study to show the sound attenuation of audible fire alarm device in apartments. We measured and analyzed the sound attenuation level in seven units. The result showed that it was not sufficient to detect the sound from the fire alarm device in bedrooms. Whether the fire alarm device worked or not, the differences of sound level in bedrooms were below 1$\sim$10dBA. To give the minimum sound level 60dBA in bedrooms, the proper sound levels from alarm device installed in livingrooms were suggested using computer simulation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.480-485
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• 2002

The overall noise reduction was compared in regard to the vibrational characteristics of floor impact noise in a multi story residential building which has several noise reduction treatments. The vibration through its structural elements such as wall, floor and ceiling and sound emitting were investigated for each insulation treatment. It was found that, in case of heavy-weight impact noise, the vibration energy is emitted mostly from ceiling, but for the light-weight impact noise, most of the energy comes through ceiling and walls. That is, the vibration of a ceiling is the main factor that determines the frequency characteristics of the transmitting noise to lower floors.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.8
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• pp.886-895
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• 2008

Resilient materials are generally used for the floating floors to reduce the floor impact sound. Dynamic stiffness of resilient material have a close relation with the floor impact sound reduction. In this study, to examine the relationship between dynamic stiffness and lightweight impact sound level, the dynamic stiffness and floor impact sound level of 51 resilient materials were measured. The impact sound level of each of these resilient materials, whose dynamic stiffness was measured, was measured before and after installation, and the level difference (${\Delta}L$) was analyzed. The result of test showed that the dynamic stiffness of resilient materials decreased, the lightweight impact sound level also decreased, and there was a correlation between the dynamic stiffness and the lightweight impact sound, especially in the low frequency domain.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.682-685
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• 2005

In this research, how the evaluation of the spacial image influenced by the environmental friendly elements included in the visual information, and how the selection of the sound changed depending on the characteristics of spatial image by the 40 subjects were carried out. Vast tracts of green land and the waterfront were highly preferred and impressive than the other spaces. The green music, signal with water sound and bird chirping sound were highly scored. In the frequency characteristics of the factors, the first factor was artificial sound(high at the low frequency band), the second was natural sound(uniform at all frequency band) and the third was water sound(high at the middle and high frequency band over 500Hz). This shows that the proposal of the sound which has the frequency characteristics fit to the spacial image should be selected for the soundscape of the target space.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.600-605
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• 2000

The aim of this study is to compare the sound insulation performances of window depending on the measurement methods through the field test and analyze the factors that affect the sound insulation performances. Four measurement methods which are specified in the Koran Standard 2235 and the International Standard 140-5 were selected for the study; the outdoor sound source method which is classified the l000mm method and the 10mm method, the indoor sound source method, and the ISO method. The result of this study is that the sound insulation performance of the windows was the best when measured according to the ISO method and the worst the indoor sound source method. Through the study it was found that the main factors affecting the sound insulation performance of the windows were the correction of the specimen's area and the equivalent sound absorption area of the receiving room.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.8
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• pp.573-580
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• 2002

Generally the ceiling frame of apartment house is made of wood. But the wood frame has several problems due to the natural properties such as distortion by shrink, low fire resistance and material loss in the construction field. And it has some defections in sound insulation performance. Therefore it is necessary to develop a new method that can be used as a ceiling frame. This study aims to analyze and to compare the sound insulation characteristics against the floor impact sound between wood ceiling frame and M-bar frame which is made of steel. The results of this study are like these. M-bar frame is more effective than wood ceiling frame in sound insulation. And sound absorbing or sound insulation materials which can be Put on gypsum board are helpful to improve floor impact sound insulation performance.