• 한국디자인학회:학술대회논문집
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• 한국디자인학회 2005년도 춘계 학술발표대회 논문집
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• pp.54-55
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• 2005

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.909-917
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• 2007

Recently the trend of automobile industry is that IQS evaluation index against a sensitivity quality is increasing. To reduce rattle noise due to speaker sound at low frequencies, it is required the advanced investigation of a package tray panel and a door module panel. This paper optimized the design parameters of package tray panel according to the theoretical background about robust design and suggested the design guideline for resonance avoidance and the reduction of vibrational sensitivity considering the excitation frequency of woofer speaker. In addition, it is suggested the design guideline of a door module panel through the sensitivity analysis in case of the speaker excitation. Finally, the design factor analysis of the quality deviation of a mother-car will make it possible to guarantee the stable characteristics of vehicle vibration in the early stage of vehicle development. These improvements can lead to shortening the time needed to develop better vehicles.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.611-614
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• 2005

The introduction of the sound based on the soundscape concept has the effect to offer comfortable sound environments at the public spaces by masking undesired ones and to identify the spaces. Sound installation, sound sculptor and the soundscape are used for these purpose, but the most important factors to be considered therein are to determine what kind of sounds to offer and how to adjust them to the changing circumstances. But, installing, maintaining and adjusting the soundscape system directly in the field will ensue numerous problems as well as high costs. And, even if it was epochal and novel when the soundscape is first installed at a space, new different sound environment is necessary to continue the effectiveness as time goes. Thus, this study aims at devising the instrument system that has the artificial intelligence, enables to remote control, with a great ease, numerous variables, reproduce most agreeable sound sources, and can produce the proper sound fit to the space automatically and spontaneously.

• Journal of the Korean Wood Science and Technology
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• 제47권1호
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• pp.33-39
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• 2019

The square timbers of larch having cross section of $90mm{\times}90mm$ were glued laterally to be formed $1,200mm{\times}2,400mm$ panels which were used as cores for CLT wall panels. Then, structural plywood panels having size of $1,200mm{\times}2,400mm$ were used as cross band covering the small square timber cores to manufacture CLT wall panels. The sound absorption rate of CLT wall panels and polyester board attached CLT wall panels were investigated. The mean sound absorption coefficients of the former and the latter in the frequency range of 100-6400 Hz were 0.21 and 0.74, respectively. The noise reduction coefficients (NRC) of those were 0.21 and 0.40, respectively. Also, the mean sound transmission loss of CLT wood panel in the frequency range of 50-1600 Hz was 45.12 dB and that value at the frequency of 500 Hz was 42.49 dB. It was suggested that the polyester board attached CLT wall panels could be used as housing wall because of its high sound absorption rate and high sound transmission loss.

• 한국자동차공학회논문집
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• 제17권4호
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• pp.24-31
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• 2009

This paper has been focused on the development of integrated automotive muffler system to meet getting more stringent sound quality target. Typically, muffler system consists of resonator and main muffler. The many varieties in exhaust pipe routing and the flexibility in muffler design make it possible to design an exhaust system to deliver tailpipe sound for specific sound quality requirement. In recent, it is strongly recommended that the function of resonator be merged into that of main muffler due to severe space limitation of underbody. The main objective of the paper is to study the effects of various geometrical parameters on the muffler performance. This work has succeeded in eliminating resonator without loss of muffler performance. This work has also investigated the effect of diameter of hole, geometries of pipes and location of muffler on the sound quality.

• 한국음향학회지
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• 제19권4호
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• pp.69-76
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• 2000

본 연구에서는 Class IV Flextensional 트랜스듀서의 여러 설계변수들에 따른 음압 변화 및 열 발생 경향성을 유한요소 해석법으로 해석하였다. 해석되어진 결과를 바탕으로 최대 음압을 구현하고, 열 발생이 최소인 중심 주파수 1 kHz를 가지는 Class IV extensional 트랜스듀서의 최적구조를 설정하였다. 본 연구에서 설정한 최적구조는 기본모델에 비해 음압이 2배 이상 크고 열 발생은 아주 작은 것으로 나타났다. 본 연구의 결과는 향후 다양한 중심 주파수 및 최대 음압을 구현하고 열 발생이 최소인 Class IV Flextensional 트랜스듀서를 설계함에 있어 유용한 자료로 활용될 수 있을 것이다.

• 한국음향학회지
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• 제30권3호
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• pp.115-122
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• 2011

본 논문에서는 십자 형태로 구성된 네 개의 마이크로폰을 이용하여 일반화된 상호 상관 기법을 적용한 음성 도달시간 지연을 측정하여 정확한 음원 방향을 실시간으로 계산하는 방식에 대해 제시하였다. 기존 시스템에서는 마이크로폰 어레이 신호처리를 위해 데이터 수집 장치를 필요로 하므로 시스템을 내장하기 힘들고, 또한 DSP 프로세서를 사용한 음원방향 인지는 마이크로폰의 채널의 수가 늘어날수록 실시간 처리가 어려워지는 두 가지 단점이 있다. 본 논문에서는 이러한 한계를 극복하기 위하여 마이크로폰 어레이 신호처리를 이용한 향상된 음원방향 인지 하드웨어의 개발을 제안하였다. 공간 구분 기법을 이용한 효율적인 설계 및 검증방식을 제안하였고 이를 통하여 보다 정확한 방향 추정과 설계시간 단축이 가능하다. 최종적으로 음성 코덱과 FPGA를 이용하는 임베디드 시스템을 위해서 사용이 가능한 시스템을 개발하였다. 실험 결과에 의하면 PC 기반이나 DSP 프로세서를 사용한 경우에 비해 보다 빠른 처리 시간을 보였다.

• 한국음향학회지
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• 제28권3호
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• pp.260-267
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• 2009

원하는 복잡한 음장을 지정된 구역에 정확히 형성하는 것은 음향 어레이를 이용한 응용에 있어서 가장 어렵고도 중요한 일이다. 이를 해결하기 위해, 본 논문에서는 역 경계요소법을 원용한 음향홀로그래피 방법을 이용하여 원하는 음장의 특성을 얻기 위한 음원 어레이의 필터 계수를 설계하는 방법을 제안하였다. 음원 파악에 적용되는 음향 홀로그래피는 음장에서의 음압을 측정하여 표면에서의 음원 특성을 재구성하게 되는데, 이와 유사한 음원 설계 문제에서는 목적하는 음장 특성이 주어진 조건이 되며, 음원의 체적 속도는 이러한 음장을 얻기 위한 출력 신호가 된다. 설계 과정에 있어서 먼저 목표 음장의 특성 제한 조건을 갖는 음장 데이터를 구성하고, 음원과 공간을 경계요소법으로 모델링 한 뒤, 소요되는 음원의 정보를 역으로 유도한다. 예제로서 16개의 스피커를 갖는 어레이를 이용해 전방의 반은 평면파 전파, 나머지 반은 정숙공간을 동시에 갖도록 하는 목표 음장을 구현하였다.

• 한국소음진동공학회논문집
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• 제14권3호
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• pp.214-223
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• 2004

This study aim to find an appropriate window for classrooms to provide proper sound insulation against aircraft noise and to achieve this goal, measurements were taken of the sound insulation performance of windows with various thicknesses of inner air space and sound absorption materials in the inner air spaces. As a result of this study the improvement of the sound insulation performance of windows(single, double and triple window) was shown through the analysis and the measuring of windows with these characteristics. These results may be applied to the manufacture of window frames and provide basic data for the improvement of the sound insulation performance of windows.

• 소음진동
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• 제9권4호
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• pp.730-737
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• 1999

This paper illustrates the sound vibration phenomenon of mono type TV set produced by spearker and suggests guidelines for reducing the noise induced by the sound vibrations. In order to illustrate the sound vibration phenomenon, the structural acoustic coupled analysis for the grill and cavity of speaker and structural analysis for main frame are performed. To veify the structural analysis results, experimental modal test is carried out. It is found that the acoustic excitation in the cavity is negligible and main sound vibrations occur near the bottom of TV set. An improved model is found by doing structural modifications based on structural analysis and sound vibration tests are performed to verify the validation of the improved model. The obtained results are applied to similar models and design guide lines for noise reduction are suggested.