• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문초록집
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• pp.333.1-333
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• 2002

This paper suggests the noise reduction method of the engine cooling fan. It was estimated the fannoise contribution at the engine room and identified the noise source at the rotating fan by sound intensity method, first. And it has been developed the program for predicting the noise spectrum of axial flow fan. The radiated acoustic pressure is expressed the discrete frequency noise peaks at BPF and its harmonics and the line spectrum at the broad band by the noise generation mechanisms. In this paper it is shown that the comparison of the measuted and calculaed noise spectra of fn for the validation of the noise predictiong program. And this paper presents the characteristics of a fan noise due to modify the design parameters. Accordingly, it was obtained the design parameter values for noise reduction of fan.

• 한국음향학회지
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• 제40권6호
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• pp.566-570
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• 2021

본 연구에서는 차량 가속음에 대한 운전자와 탑승객의 지각적 차이를 평가하였다. 주관 평가를 통해 가속음의 크기에 따라 성가심과 스포티함의 지각 정도에 큰 차이가 있음을 발견하였다. 주관 평가는 주행 영상, 모션, 진동, 소리를 재현할 수 있는 멀티모달 시뮬레이터를 기반으로 가속음의 크기를 3 dB씩 5 단계로 변화시켜 지각되는 성가심과 스포티함이 평가되도록 설계되었다. 실험 결과 성가심과 스포티함의 지각 강도는 운전자보다 탑승객일 때 더 큰 것으로 나타났다. 한편, 가속음 크기의 변화에 따라 성가심의 민감도는 운전자가 탑승객보다 35 % 더 크게 나타났고 스포티함의 민감도는 74 % 더 큰 것으로 나타났다. 본 연구 결과는 능동 음향 설계를 활용한 가속음 개발 시 운전자와 탑승객의 음량을 차별화하여 가속음에 대한 만족도를 향상 시킬 수 있는 사운드 디자인 방향 설정에 활용될 수 있을 것으로 기대된다.

• 한방안이비인후피부과학회지
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• 제36권2호
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• pp.45-59
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• 2023

Objectives : The purpose of this study is to analyze the various methods of sound therapy(ST) applied to tinnitus patients and their effectiveness, and to suggest an effective method that can be applied in clinical settings. Methods : Studies published from January 2018 to March 2023 were searched on 5 databases(Pubmed, RISS, OASIS, KISS, KCI). All RCTs that applied sound therapy as a main treatment method were included. Results : 14 studies were included. In 13 studies, sound therapy was statistically significant in improving tinnitus. Basic sound therapy was used in 6 studies(42%), followed by tinnitus rehabilitation therapy(TRT)(n=5, 35%). White noise(n=11, 75%) and nature sound(n=4, 28%) were the most frequently used sound sources. In the case of intensity, mixing point were the most common with 6 studies(42%). The mobile application(n=4) was the most frequently used implement. The application time of sound therapy per day was more than 3 hours(n=7), and the total treatment period was more than 3 months(n=9). Conclusions : Our findings indicate that sound therapy could be considered as an intervention for tinnitus patients. For better use, we suggest a basic type of sound therapy or TRT using white noise or nature sound at the mixing point level provided as a mobile phone application. In addition, the treatment period is recommended to be more than 3 hours/day for 3 months.

• 한국통신학회논문지
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• 제36권5C호
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• pp.309-316
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• 2011

본 논문에서는 입체음향시스템을 위한 대표적인 상호간섭제거 기법인 머리전달함수만 (head related transfer function, HRTF) 이용한 기법과 두 귀에 도달하는 소리의 시간차와 세기차를 (interaural time/intensity difference, ITD와 IID) HRTF와 함께 이용한 기법의 상태지수와 ITD/IID 수준을 보이고, 이로부터 두 기법의 유효청취범위를 보인다. 입체음향시스템의 유효청취범위는 청취자가 의도된 음향의 입체감을 왜곡 없이 느낄 수 있는 공간으로 등역 (equalization zone) 또는 sweet spot으로도 부른다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.597-600
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• 2009

Sound transmission loss (TL) is experimently investigated on the multi-layered panel used for the floor of a tilting train. Measurement of the intensity transmission loss is performed according to ASTM E 2249-02. The floor structure consists of corrugated steel panel, glass wool, plywood and cover. On the corrugated steel panel, TL drop by local resonance is considered and the TL improvement effect by damping treatment is estimated. Total sound transmission loss of the entire floor structure is obtained and the contribution of each layer is examined.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.326-331
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• 2011

Aluminum extruded panel used in a high speed train shows high stiffness, however, its sound insulation performance is remarkably decreased by local resonance phenomena. In this paper, improvement strategy of the sound insulation performance is proposed for the floor extruded panel used in HEMU-400x, 400km/h class next generation high speed train under development, and the improvement effect is verified by experiment. Aluminum extruded panel specimen for the floor is manufactured and urethane foam is installed in the core of the panel. Based on ASTM E2249-02, intensity transmission loss is measured and the improvement effect in local resonance frequency band is verified. Finally, improvement effect of the sound insulation performance is estimated on the layered floor structure including the foamed aluminum panel.

• 대한기계학회논문집A
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• 제22권4호
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• pp.879-886
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• 1998

It is very important to understand the vibration and noise characteristics of a structure to developed quiet machines and lessen their noise. In this paper, the vibration and sound radiation characteristics of a simple and a bar-stiffened plate have been investigated using numerical and experimental techniques. In numerical process, FEM analysis has been performed for the vibration level ; the time-space squared and averaged velocity and BEM analysis for sound radiation parameters ; sound power and radiation efficiency. In experimental process, FFT signal processing method has been used. While a power from an exiciter is applied to the structure by using a point contact, sound intensity and vibration level has been measured. Based on these two data, the radiation efficiency has been calculated. Results show that the radiation efficiency for the stiffened structure increases compared to the simple plate, due to the extra edges provided by the stiffener.

• 소음진동
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• 제10권2호
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• pp.240-246
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• 2000

One of the widely accepted methods for evaluating the interior sound quality of automobiles is Articulation Index(AI). The AI actually measures the articulation level of the sound in the vehicle cabin as passengers talk to one another. In this study, the effect of two different absorption materials inside the cabin on AI has been investigated by ray-tracing method : one is firewall, the other is celling. It turns out that the back seat location is found to be strongly dependent on the type of absorption materials treated at the celling, since the sound absorbing area is different due to the location and the firewall is situated in the "Reverberation Radius". The proposed methdo could be used to improve the sound quality of automobiles at the design stge.sign stge.

• 대한음성학회지:말소리
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• 제57호
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• pp.85-97
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• 2006

This paper suggests an algorithm that can estimate the direction of the sound source in real time. The algorithm uses the time difference and sound intensity information among the recorded sound source by four microphones. Also, to deal with noise of robot itself, the Kalman filter is implemented. The proposed method can take shorter execution time than that of an existing algorithm to fit the real-time service robot. Also, using the Kalman filter, signal ratio relative to background noise, SNR, is approximately improved to 8 dB. And the estimation result of azimuth shows relatively small error within the range of ${\pm}7$ degree.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.956-959
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• 2007

The extension of a road system result from construction of the builling near the noise source as the roads, railroads. Many people who have a living space near the road are damaged by the noise generated the road system. Therefore, the damage will be reduced by the appropriate measure like putting some distance between receiver and source. The windows are weak among the building materials. But mainly we uses the windows as building exterior materials. So the sound insulation of the balcony windows was measured and compared.