• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.159-160
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• 2009

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.639-643
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• 2014

• The Journal of the Acoustical Society of Korea
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• v.38 no.4
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• pp.396-405
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• 2019

The speech privacy of closed office rooms located in a university campus was measured and assessed in terms of SPC (Speech Privacy Class) values. The measurements of two quantities, the LD (Level Difference) between a source and a receiving room, and the background noise level ($L_b$) at the receiving room were carried out in 5 rooms located in 3 different buildings in the university campus. Each of the 5 rooms was adjacent to both offices and corridors through walls. The TL (Transmission Loss) between the source and the receiver room was also measured to compare the difference of two standard methods, ASTM E2836-10 and KS F 2809. The present results show that the speech privacy of the 5 office rooms is not met the requirement for a minimum SPC values of 70. A minimum LD value of 41 dB between the source and the receiver room should be achieved for having a SPC value of 70 when the mean measured value of $L_b$ at the receiving room is 29.2 dB. That is, the TL(avg) value averaged over the octave bands from 160 Hz to 5000 Hz between the source and the receiver room should be or greater than 40 dB. The most important architectural factor influencing the LD value is the presence of openings, such as doors, and windows, on the adjacent walls between the source and receiving room. Therefore, if the opening of the adjacent wall is replaced by an opening with high sound insulation, the appropriate SPC value of the research and office rooms can be achieved.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.942-945
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• 2006

In order to measure the sound transmission loss(STL) of a test specimen such as windows, which is smaller than the test opening, a special partition is built into the test opening and the specimen is placed in that partition. This paper discusses how the measured STL is changed by the partition when a small-size window of high sound insulation is mounted. Theoretical and experimental investigations are carried out to quantify the effect of the filler wall. The results reveal that the smaller the window size is, the higher sound insulation performance of the filler wall is required in order to measure the accurate STL of the specimen. It is found that the insufficient sound insulation of the filler wall leads to the lower measured value of the window's STL.

• Journal of KSNVE
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• v.6 no.5
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• pp.535-540
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• 1996

공장내 소음을 형성하는 각종 발생 형태 및 소음원, 전달 형식의 분류에 따라 특성을 간략히 살펴보았다. 각 소음원 및 전달 경로의 특성을 확실히 이해하면, 혀ㅌ상을 파악하는 작업이나 소음제어 대책을 수립하는데 있어서 매우 효과적으로 대처할 수 있다. 일반적으로 공장소음 대책은 음원대책과 전달경로상의 방지 대책을 생각할 수 있는데 음원대책으로는 공장에서 사용하는 기계중 저소음 기계를 선정 하도록 권장해야하고, 일단 설치된 소음 발생원 기계에 대해서는 철저하게 차음, 흡음 조치를 취하여야 한다. 공장내부 소음 발생원에 대해서는 흡음재료를 사용하여 소음을 흡수하고 차음별을 설치하여 음의 차단에 신경 써야한다. 한편 기계 작동상의 주의, 작업 공장의 개선, 낮과 밤의 작업시간 등을 조절하여 인근 주민과 작업자 스스로에 대한 소음 피해를 막고, 피해를 입은 자에 대해서는 법적으로 보상조치하는 제도와 관리 감독이 철저히 지켜져야 한다. 끝으로 공장내.외부의 소음을 정확하게 측정 분석하여 작업장 내의 소음을 최대한으로 제거하여 쾌적한 작업장의 분위기를 만들 어야 할 것이다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.197-202
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• 2001

The compressor is one of major noise sources in air conditioner outdoor units, especially deteriorating the sound quality. Therefore, the sound insulation materials layered with sound absorption materials are applied around compressors. In this study, the performance of the sound insulators is examined by measuring the insertion losses in power base and the effects of sound absorption materials, method of application and the shape of the insulators are also investigated. The importance of minimizing the opening is revealed well.

• KIEAE Journal
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• v.9 no.5
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• pp.63-68
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• 2009

As with the disappearance of a living room window due to the trend in apartment housing construction that prefers a larger, expanded living room, the sound insulation performance of the balcony window is becoming an important factor to determine the level of indoor noise at an apartment unit. Considering that the indoor noise inside an apartment unit is mandated by law at or below 45dB(A), the balcony window is increasingly assuming an even more important role. Sound insulation performance of the window was measured by examining differences in data involving varying angles of incidence of the sound source as obtained from the same balcony window. Also, acoustic intensity measuring was performed at and around the window to determine its sound insulation quality. Results of measuring on the sound source's angles of incidence indicated that the performance showed some differences in lower frequency ranges, though with no significance. Intensity measuring results showed that the sound insulation performance was reduced near the connection part of the window and the window frame.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.1099-1103
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• 2001

In room acoustics, reverberation time (RT) is the most important and general factor that represents character of room or inner space. However, RT, especially in low frequency range, can have the different value according to the measuring points and methods. This study comprehends the cause of error occurring dominantly in low frequency range when RT is measured and examines that the each error of RT measured in the cabin and reverberation chamber having different properties, influences what extent on sound transmission loss (STL)

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.1
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• pp.35-44
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• 2014

Sound pressure levels in the receiving room while testing airborne sound insulation performance are varied by the measuring points. This may increase the measurement error, then decrease the measurement reliability. With this reason the research has carried out on the method to reduce deviations of sound pressure level in the ISO type rectangular laboratory focusing on the measurement of airborne sound insulation performance. Tests were made to see the effect of sound absorption in the receiving room, loudspeaker locations, microphones locations and flanking transmission path. Consequently, it was resulted that sound absorption in the receiving room and the loudspeaker location have influence on the sound level deviations especially in the low frequency. The microphone location was very important to get measurement reliability. The effective measuring point, which the sound level difference with average sound pressure level is within 2 dB, could yield most reliable average sound pressure level. Therefore it is necessary to find the effective measuring points in the receiving room. Flanking transmission path should be sealed using sound absorber or magnet etc. to prevent from lowering the sound insulation performance.

• Journal of the KSME
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• v.33 no.1
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• pp.14-21
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• 1993

본 해설에서는 가정용 진공청소기에서 일반적으로 사용되는 진동 . 소음 측정기법과 진공청소 기의 저소음화를 위해 별도로 고안된 흡음방이 장착된 진공청소기에 대한 측정예를 소개하였다. 본 해설에서 다룬 흡음방은 일반적인 소음기의 원리를 응용한 장치로서 저소음화가 특히 요구 되는 가정용 진공청소기의 효과적인 차음장치로 사용가능함도 확인하였다. 추가적으로 진행될 과제는 흡기구에서 배기구에 이르는 진공청소기 본체 내부의 긴유로에 대한 개선과 흡음방 내에 부착되는 보다 우수한 흡음제의 개발, 진공청소기의 전 부분에 대한 기밀유지 등이 있을 수 있 으며, 위의 분야에 대한 추가적인 지식들이 보강된다면 흡음방의 효과를 보다 높일 수 있는 전체 시스템이 형성될 수 있을 것이다. 음 저감의 효과를 감안할 때 수용 가능한 정도라 판단된다.