• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.4
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• pp.481-487
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• 2017

The purpose of this study is to develop the hybrid sound-absorbing materials that is made from organic polyurethane sponge impregnated with inorganic binder solutions. The inorganic slurry which is made from ${\alpha}$-hemihydrate gypsum mixed with 60% water, and various additives including plasticizer are used as binder. The test specimens are prepared and tested for sound absorption performance by the impedance tube methods. From the test results, noise reduction coefficient(NRC) of development materials specimen bound by the inorganic binder slurry is 0.41. They are 2 times or more higher than commercial products specimens bound by organic materials only which have NRC values in the range of 0.14 to 0.28. The polyurethane sponge specimens impregnated with inorganic gypsum slurry binder have a good balance between performance and cost, and have proper properties in density, thermal conductivity, non-combustible, and absence of harmful substances as sound-absorbing internal boards for noise barrier wall. It is apparent that the good sound absorption materials can be produced according to the optimum mix design that is recommended from this study.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.8
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• pp.592-597
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• 2013

It is widely known that the sound insulation of soundproof panel is highly correlated to two factors, surface density of material and the frequency of noise. Accordingly, the character of traffic noise released in actual situation is important requisite for determining thickness to determine surface density and material of soundproof panel. This present study selected polymer panel with advantage of light weight and workability and evaluates according to frequency of traffic noise. Polypropylene (PP) and high-density polyethylene (HDPE) were selected as subjects based on economic valuation and efficiency. The sound transmission loss of selected polymer panels were compared with the currently used panels such as polycarbonate (PC) and polymethyl methacrylate (PMMA) depending on thickness and materials. As a result, PC showed the highest sound transmission loss followed by PMMA, HDPE, and PP in range of mass law. In terms of acoustic performance on thickness, the transmission loss increased with thickness of soundproof panel meanwhile coincidence dip was observed in lower frequency where had reduced transmission loss. Therefore, it is suggested that after determining target frequency, the kind of materials and thickness of soundproof panel need to be designed so that traffic noise can be more efficiently reduced.

• International Journal of Highway Engineering
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• v.15 no.6
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• pp.41-47
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• 2013

PURPOSES : The purpose of this study is about noise which is generated from roads and is consist of irregular frequency variation from low frequency to various band. The existing methods of noise reduction are sound barrier that uses insulation material and absorbing material or have applied passive technology of noise reduction by devices. The total frequency band is needed to apply active noise control. METHODS : In this study applies to the field of road traffic environment, signal processing controller and various analog signal input/output, the amplifier module is based on parallel-core embedded processor designed. DSP performs the control algorithm of the road traffic noise. Noise sources in the open space performance of evaluation were applied. In this study, controller of active signal processor was designed based on the module of audio input/output and main controller of embedded process. The controller of active signal processor operates noise reduction algorithm and performance tests of noise reduction in inside and outside environment were executed. RESULTS : The signal processing controller with OMAP-L137 parallel-core processors as the center, DSP processors in the active control operations dealt with quickly. To maximize the operation speed of an object and ARM processor is external function keys and display for functions and evaluating the performance management system was designed for the purpose of the interface. Therefore the reduction of road traffic noise has established an electronic controller-based noise reduction. CONCLUSIONS : It is shown that noise reduction is effective in the case of pour tonal sound and complex tonal sound below 500Hz by appling to Fx-LMS.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.3
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• pp.607-612
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• 2009

For the development of ecological sound proof wall, successful seed germination and growth of plants are very important. In our present study, we observed germination of thirty five different seed species in growth chamber at $24^{\circ}C$, humidity 60% and alternation of 12 hours photoperiods. Germination of same seeds were carried out at room temperature on 6:4, 7:3, 8:2, and 9:1 proportion of pure and mineral soils respectively. Out of studied species, maximum germination was recorded for Perennial penant (92%), followed by Brassica napus (86%), and Silene armeria (82%). The measurement of root/shoot length showed, maximum root/shoot length for Perennial penant, followed by perennial sonata and Rebolsentri sp. Based on germination percentage and root/shoot length of germinating seeds, we considered Perennial penant, perennial sonata and Rebolsentri sp. were proper species for the construction of ecological sound proof walls

• Journal of The Korea Institute of Healthcare Architecture
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• v.18 no.1
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• pp.15-23
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• 2012

The purpose of this research is support blind person's daily walking. In order to achieve the purpose, we investigate how the environmental information is used for their daily walking both in residential and commercial areas considering the characteristics of walking. In the investigation, interview to the persons concerned is carried out and all the conversation with them is recorded with a voice recorder. Moreover, the environmental information that may become clues is plotted on a map together with photos. The results are as follows; (1) Environmental information which the blind persons use is different depending on the role of its own of place, such as place confirmation, direction decision, distance understanding. (2) It is demonstrated that the information acquisition from sound is effective when they especially understand place and location.

• Korean Institute of Interior Design Journal
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• v.13 no.3
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• pp.17-25
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• 2004

In Cis study, the problems of the correspondence of the museum to universal design have been grasped and examined. As the result, four problems have clarified as follow: (1) At the present, many barriers exist for the visually handicapped in the museum. In this case, the correspondence to universal design should be strengthened in the future by using Braille and sound to illustrate the display and guide. (2) The universal design of "the transfer of information" has been considerably retarded from the universal design of "the movements of observer" in the correspondence. The communication and information services in the museum are very important, and the correspondence is urgent. (3) It is necessary that the expert committee need to be installed to grasps and solves the barrier in the museum. (4) In order to execute the universal design in the museum, it is necessary that the consciousness of the museum's staff to universal design should be improved. should be improved.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1823-1828
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• 2000

Power transformers, air-intakes, stacks in a combined thermal power plant are the main noise sources. Power transformer noise among them has being get a target of public complaint due to 480Hz component of its pure tone. The source is mainly magnetostrictive vibration of the transformer core. The first countermeasures was installing sound barrier on the front of transformer. However, 500Hz, center of the frequency is not reduced. This paper includes the measurements of noise level at the near resident apartment, the identification of noise transfer and the countermeasures for noise sources. Cavity resonance type of noise reduction devices was installed on enclosuring wall of transformers. As a result, the noise level from transformer is reduced about 3dB.

• KIEAE Journal
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• v.6 no.4
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• pp.69-76
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• 2006

The effects of the additional visual and auditory stimuli on the loudness evaluation of road traffic noise was investigated by the method of magnitude estimation. As a result, it was shown that additional visual stimulus of noise barrier can influence on the loudness perception of road traffic noise. Also, additional auditory stimuli such as green music or sound of flowing water can influence on the loudness perception of road traffic noise, approximately 5~10% lower than the absence of stimuli. But this effect was disappeared in the range of over 65dB(A).

• Proceedings of the KAIS Fall Conference
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• 2008.11a
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• pp.375-378
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• 2008

생태방음벽의 적합한 식물종은 최소한의 유지관리만을 통해 성장할 수 있는 식물을 선정하는 것이 매우 중요하다. 지상부의 성장이 억제되고, 지하부의 성장이 활발해야 하기 때문에 레볼센트리, 소나타, 페난트 등이 가장 적합한 식물종으로 판단된다. 코스모스의 경우는 발아율, 생명력, 번식력 등이 매우 좋으나 지하부의 성장이 다른 품종에 비해 약 35%이상 크게 성장하고 지하부의 성장이 50%미만이기 때문에 식생방음벽으로서는 적합하지 않다. 그리고 여러 조건을 충족할 수 있는 추후 실험이 이루어져야 할 것으로 사료된다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.939-942
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• 2014

고속도로 교통 소음 저감을 위해 상용소음예측프로그램인 SoundPLAN과 소음예측 시 주로 사용하는 도로 교통 소음예측식인 RLS-90을 이용하여 경제적이고 효율적인 방음대책 설계방안에 대한 연구를 하였다. 대상지역에서 측정한 실제 소음도와 예측 소음도의 차이를 비교하여 모델을 검증하고 장래교통량에 대하여 소음을 예측하여 방음대책을 설계하였다. 방음벽의 높이와 길이, 저소음 포장의 길이를 조절하고 저소음 포장과 방음벽을 혼용했을 경우에 대하여 소음규제 기준에 적합하게 설계하였고 각각의 설치 단가를 이용하여 경제성을 비교하여 보다 효율적인 방음대책을 알아보았다.