• Journal of Power System Engineering
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• v.10 no.4
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• pp.78-82
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• 2006

Recently, The demands for the reduction of noise generated by transformers have been increasing. Almost all of the noise generated by transformers is a result of magnetostricitive vibration in the core. The noise radiates into the atmosphere from the tank through the insulation oil. As the noise of transformer irritates residents, needs for decreasing the noise of transformer have been arised. One method of reduction such a noise is to build a free-standing enclosure of concrete and steel plates around the transformer. However, this method has some disadvantages. Another method of noise reduction is to mount a close-fitting sound insulation panel on the side of a transformer tank. Side plate vibrations of transformer are transmitted to such a sound insulation panel along two paths. In one case, they are transmitted through air by sound pressure and in the other through supporting structures. In the paper, the vibration and noise effect which is transferred from reinforce channel to insulation panel generated by transformer have been identified for the several kinds of insulation panel and damping sheet analytically and experimetally.

• KIEAE Journal
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• v.14 no.1
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• pp.83-89
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• 2014

The residents' demand for the comfortable life is promoting development of wall and window which has high sound insulation performance. To develop wall system, various aspects should be considered on the environment, material, construction and structure. Especially focusing on the acoustical view, the economical solution is one of the most critical point. Recently the interest on the partition wall is being increased, because it is useful for the Rahmen type apartment which is considered as an alternative to reduce floor impact sound. This study examines simplified measurement method of airborne sound insulation applied small size specimen, in order to save money to be used for the standard specimen then to promote the development process. The results showed that the simplified method could be effective for the wall system the sound insulation performance upto Rw 50 dB, and for the judgement of rank order of sound insulation performance of the similar wall type while developing.

• Journal of the Korea Furniture Society
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• v.24 no.4
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• pp.426-432
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• 2013

Fire resistance and impact sound insulation tests were performed for a floor assembly, of which stiffness was reinforced by shortening the span of floor joists by installing glulam beam additionally in the middle or one thirds of the original span, and which an additional ceiling component was installed apart from floor structure. By applying the isolated ceiling, timber framed floor showed 1 hour of fire resistance even in case that dead load was increased by considering cement mortar layer for radiant floor heating. Insulation performance against light and heavy impact sound was improved significantly by applying the sound absorbing layer of big mass and high elasticity in addition to the stiffness improvement and isolated ceiling.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.10-12
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• 2014

In ISO 10140-5:2010, defines the reverberation time conditions of the receiving room. The sound absorption side of test specimen is installed in the source room generally. In this study, examined at the change in the sound insulation characteristics for the test specimen of asymmetric structure attached sound absorbing material by changing the installed position. A difference of sound insulation performance was maxium Rw 1 dB, it is preferable to place the larger sound absorption area in source room.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.5 s.98
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• pp.519-526
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• 2005

Recently, the interest on the comfortable dwelling environment is increasing and the effort to solve the problem of exterior noise was tried. The propose of this study is to suggest the design of balcony window in apartment and to evaluate the sound insulation of it. So, we designed five types of balcony window which were considered not only sound insulation but ventilation. The sound reduction index of window was evaluated by the measurement in mock-up room. The results showed that case 2 improved about 6 dB in the weighted apparent sound reduction index than case 1, and case 3 reduced about $39 \%$ in construction cost than case 4.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.445-450
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• 2004

Recently, the interest on the comfortable dwelling environment is increasing and the effort to solve the problem of exterior noise was tried. The propose of this study is to suggest the design of balcony window in apartment and to evaluate the sound insulation of it. So, we designed five types of balcony window which were considered not only sound insulation but ventilation. The sound reduction index of window was evaluated by the measurement in mock-up room. The results showed that case 2 improved about 6dB in the weighted apparent sound reduction index than case 1, and case 3 reduced about 39% in construction cost than case 4.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.946-949
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• 2006

This study is a trial to make a design chart of sound insulation for multiple panel. Dilatational frequency, ${\Large f}_d$ becomes a key factor for optimal design since it acts like a turning point in sound insulation performance of such panels. Hence, in tuning the ${\Large f}_d$ optimally, elastic modulus of core material and thickness of the skin panel is designated to parameters. Based on these parameter, a design chart of sound insulation for multiple panel is made. Its applicability is proved by the case study of High noise reduction panel.

• Journal of the Korea Institute of Building Construction
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• v.12 no.6
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• pp.575-585
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• 2012

The extruded cement panel, which has many advantages as a prefabricated method, has been limited in its application due to its low fire-resistance. However, an extruded cement panel produced by mixing a-hemihydrate gypsum offers dramatically improved fire-resistance and is expected to have wide-ranging applications in the construction sector as an interior material or partition wall between housing units. Sound insulation performance is very important for the partition wall between housing units. In this study, the sound insulation performance of the extruded cement panel produced through the mixture of a-hemihydrate gypsum is reviewed in order to determine its usability for a partition wall between housing units and for interior materials. Through the review it was found that the wall formed using the extruded cement panels produced by mixing the a-hemihydrate gypsum have ★★★ class in sound insulation test, equal or superior compared with the other two types of extruded cement panel walls currently available in the market.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.495-498
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• 2004

In the sound insulation measurements, the influence of background (extraneous) noise is often serious problem and how to reduce its effect and to improve the signal-to-noise(S/N) ratio is an important theme. As the background noise, such extraneous noises as road traffic noise and machine noise often disturb the measurement. In laboratory measurements on specimens with high sound insulation performances, even the internal noise of the measurement system can become a problem. To improve the signal-to-noise ratio and to improve the measurement accuracy, various kinds of digital signal processing techniques can be applied. In this paper, four kinds of digital signal processing techniques are applied and their effectiveness is examined by a simple sound insulation measurement.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.407-412
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• 2013

In dry wall, noise is passed through gypsum board and stud. Noise makes gypsum board vibration. Then, the vibration passes through stud and gypsum board as resonation. And radiation as noise from surface of gypsum board into adjacent room. At this moment, according to thickness, placement and cross-section of stud, noise transmission ratio changes. Thicker stud has better sound insulation performance. Studs are apart from each other, has better sound insulation performance. But, single stud structure has restriction of thickness and arrange of studs. In this article, Sound insulation performance varies depending on the shape of the studs were studied.