• 대한음성학회지:말소리
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• 제49호
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• pp.135-144
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• 2004

In this paper, we make a study of classification normal from abnormal - normal, asthma through analysis of thoracic sound to take use thoracic sound detection system. Thoracic sound detection system has a function to store thoracic sound and analyze the data. The wave shape of thoracic sound is similar to noise and is systematically generated by inhalation and exhalation breathing, therefore, in this paper, to classify asthma sound in thoracic sound, we could discriminate between normal and abnormal case using level crossing rate(LCR) and spectrogram energy rate.

• Journal of Advanced Marine Engineering and Technology
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• 제23권4호
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• pp.473-479
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• 1999

The two-microphone sound-intensity technique has been used for the detection of defects in ra-ally loaded ball bearings. The difference in the sound-intensity levels measured for bearings with no defect and for those with intentionally introduced defects of different sizes n heir elements under various operating conditions of loads and speeds is demonstrated. The results show that of an inner-race or ball defect. It is difficult to detect defects at lower speeds. Sound-pressure measurements were also performed for comparison and it shown that the detectability of defects by sound-intensity measurements is better than that by sound-pressure measurements.

• International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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• 제3권1호
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• pp.56-62
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• 2000

The trends of recent passenger ships are becoming speedy and luxury style to enhance comfortableness in cabin. In order to meet these trend, ship designer has to improve the sound quality as well as to reduce the sound pressure level in cabins. In this paper, the trend of noise and sound quality of real high-speed coastal passenger ships are measured and analyzed, while running on their regular courses. The sound quality parameters such as loudness, roughness, fluctuation strength, and sharpness are evaluated by Zwicker loudness calculation. In addition, we try to find sensitive critical frequency band for the improving sound quality by using signal editing. Finally, the expected effective design methods are proposed to designer for the improving sound quality of passenger ships.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2003년도 하계 학술대회 논문집
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• pp.232-237
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• 2003

Sound has been rated negatively in many industrial areas as the noise to be removed. In the agricultural process such as rice milling based on grinding the surface of the rice, however, it may be anticipated that the sound can contain the some information on the process. In this research, on the assumption that variation of the shape of the rice kernel during milling may bring the change in frequency characteristic of sound signal, we tried to investigate the relationship between the milling degree in the grinding test mill and the resonance and anti-resonance frequencies (the frequencies at which the sound power has the extreme values). (omitted)

• 수산해양기술연구
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• 제46권4호
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• pp.449-457
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• 2010

This study shows that the vertical migration speed of sound scattering layers (SSLs), which is distributed in near Funka Bay, were measured by 3D velocity components acquired from a bottom moorng ADCP. While the bottom mooring type has a problem to measure the velocity vectors of sound scattering layer distributed near to surface, both the continuous vertical migration patterns and variability of backscatterers were routinely investigated as well. In addition, the velocity vectors were compared with the vertical migration velocity estimated from echograms of Mean Volume Backscattering Strength, and estimated to produce observational bias due to SSLs which is composed of backscatterers such as euphausiids, nekton, and fishes have swimming ability.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -1
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• pp.306-309
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• 2000

We developed an electronic music glove (EMG) system that could play musical scores in real time processing. The EMG system interfaces with the signal coming from the controller to the sound card in the computer. The computer, according to the status of the finger and foot switches, generates the signals to the speaker systems using the application C++ program by making use of MIDI message. The EMG systems can control up to several octave notes and duration of sound, and several musical performance expressions such as chorus, reverberation, rhythm, and volume. Finally, our EMG could play the performance of simple music depending on the choice of any kind of musical instruments in the sound card in computer systems.

• Journal of the Korean Wood Science and Technology
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• 제40권6호
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• pp.431-444
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• 2012

바닥구조의 충격음 차단성능은 바닥의 구성요소에 의해 많은 영향을 받는데, 그중 목조 바닥구조의 경우 중량의 흡읍층과 바닥구조의 강성이 주요한 영향인자로 고려되어 왔다. 본 연구에서는 국내 시공된 목조 건축물에 대해서 현장 실험을 통해 바닥 구성요소가 충격음 차단성능에 미치는 영향에 대해서 살펴보았다. 목조 바닥의 충격음 차단성능은 상대적으로 낮은 저주파수 대역에서의 음압레벨에 의해 전체적인 성능이 좌우되었으며, 흡읍층과 바닥구조의 강성 보강에 의해 저주파수 대역 음압레벨을 감소시켜 충격음 차단성능을 향상시킴을 알 수 있었다. 특히, 바닥난방을 위해 설치되는 시멘트 몰탈층과 같은 충격음 흡수층과 원래 경간의 중간 지점에 보를 설치하여 장선 경간을 줄여줌으로써 목조 바닥의 강성을 증가시킨 경우에 중량 충격음 차단성능이 크게 향상되었다.

• Steel and Composite Structures
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• 제21권2호
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• pp.249-266
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• 2016

The interest of this article lies in the proposition of using bionic method to develop a new sound absorber and analyze the efficient of this absorber in a ski cabin. Inspired by the coupling absorption structure of the skin and feather of a typical silent flying bird - owl, a bionic coupling multi-layer structure model is developed, which is composed of a micro-silt plate, porous fibrous material and a flexible micro-perforated membrane backed with airspace. The finite element simulation method with ACTRAN is applied to calculate the acoustic performance of the multi-layer absorber, the vibration modal of the ski cabin and the sound pressure level (SPL) near the skier's ears before and after pasting the absorber at the flour carpet and seats in the cabin. As expected, the SPL near the ears was significantly reduced after adding sound-absorbing material. Among them, the model 2 and model 5 showed the best sound absorption efficiency and the SPL almost reduced 5 dB. Moreover, it was most effctive for the SPL reduction with full admittance configuration at both the carpet and the seats, and the carpet contribution seems to be predominant.

• 한국생산제조학회지
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• 제6권3호
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• pp.36-43
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• 1997

In order to make unmanned machining systems with satisfactory performances, it is necessary to incorporate appropriate condition monitoring systems in the machining workstations to provide the required intelligence of the expert. This paper deals with condition monitoring for tool wear and breakage during turning operation. Developing economic sensing and identification methods for turning processes, sound pressure measurement and digital signal processing technique are proposed. The validity of the proposed system is confirmed through the large number of cutting tests.

• 한국음향학회:학술대회논문집
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• 한국음향학회 2001년도 추계학술발표대회 논문집 제20권 2호
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• pp.283-286
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• 2001

본 논문은 전기적으로 음장을 가변하여 청감적 인상에 변화를 주는 실험 결과를 기술하였다. 본 실험은 마이크로폰으로 무대의 음원을 수음하고 잔향기로 옆방향 반사음과 잔향음을 각각 생성하여 스피커로 출력하였다. 실험 결과 실내의 청감적 인상이 개선됨을 확인하였다. 또 음원 수음 시 발생하는 하울링, 실내 잔향과 다른 스피커의 음색, 잔향기에서 발생하는 음색 변조 둥 기술적 문제를 해결하였다.