• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.1276-1279
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• 2006

This article on environmental noise qualify is concerned with the relationships between the annoyance and perception and sound quality metrics according to exposition time for traffic noise. For invested the characteristics of noise quality, we conducted to the subjective experiments of the annoyance response using the absolute 100 scaling method for the traffic noise sources. The traffic noise sources are composed to varieties exposition time from 15sec to 1200sec. As the results, the first there are decreased the perception loud level for the increase of exposition time with logarithm scale, but increased the annoyance. Second, evaluation index of annoyance is correlated to the loudness(sones), tonality and logarithm scale time with R2=0.83. Also, the composition ratio of traffic noise according to exposition time has the change of range as the logarithm scale ($30{\sim}50%$), tonality($27{\sim}37%$) and loudness($34{\sim}20%$).

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.497-502
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• 2008

In this paper, we studied on an attenuation effect of automobile exhaust noise according to the direction of secondary sound source in duct ANC system. Automobile exhaust noise was recorded at 800rpm. 3500rpm and 5000rpm of a diesel engine. Directions of loudspeaker(second sound source) can be exchanged to $30^{\circ}$, $90^{\circ}$ and $150^{\circ}$ against the primary noise flow by acrylic ducts to be made for experimentation. DSP board with TMS320C6416 chip of Texas Instrument Co used to control adaptive ANC system. This ANC system is based on the single-channel FxLMS algorithm. In experiment result, when the loud speaker direction was $150^{\circ}$, the attenuation effect showed largely. In case of $90^{\circ}$ duct, the noise was a little increased. In case of $30^{\circ}$ duct, the noise was a little increased or decreased according to the frequency range and the sound pressure(dB) of exhaust noise to comply with engine rpm.

• 대한환경공학회지
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• 제33권10호
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• pp.748-755
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• 2011

1960년대 산업화 이후 기계화가 가속되어 산업발달에 많은 기여를 하였으나 고소음 작업장에서 발생하는 소음피해에 대한 대책은 거의 없는 실정이다. 특히 공장 및 작업장에서 발생하는 기계소음은 반복적으로 되풀이되어 충격적이며, 강한 소음으로 대부분의 현장 작업자들은 높은 불쾌감과 청력장애의 위험을 부담하고 있다. 이러한 관점에서 이 연구는 고소음 작업장에서 발생하는 작업기계 소음을 평가하기 위한 적정 평가어휘를 추출하고자 했으며, 이렇게 추출된 어휘는 작업 기계소음을 평가하기 위한 음향심리 실험 및 기계소음 규제기준 설정을 위한 유용한 자료로 활용될 수 있을 것으로 사료된다.

• 한국음향학회지
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• 제34권4호
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• pp.274-281
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• 2015

소음성난청은 고려 시 되어야 하는 공중보건 문제로 알려져 있지만, 큰 소음의 노출로 인해 난청이 발생됨을 많은 사람들은 잘 인식하지 못하고 있다. 본 연구의 목적은 일반인들이 얼마나 중요하고 심각하게 소음성난청에 대하여 인식하고 있는지 22개의 설문 문항을 바탕으로 조사하고 그 결과를 분석하였다. 20대부터 60대의 성인 남녀 150명을 대상으로 청력손실과 이명을 포함하여 일반적인 건강 문제들에 대한 사회 및 개인적 중요도, 소음노출과 청력손실에 대한 인지 정도, 청력 보존 방법에 대한 인식을 문답하였다. 연구 결과, 다른 건강 문제들과 비교하여 응답자 중 약 17.33 %만이 청력손실을 '매우 큰 문제'로 인식하였다. 놀랍게도 다수의 응답자인 82 %는 청력손실에 관한 정보를 듣거나 보지 못하였다고 답변하였다. 전체 응답자 중 약 85 %의 응답자들은 큰 소음이 있는 환경에서 청력 문제 및 이명을 경험한 적이 있다고 답하였지만, 그 중 11.33 %만이 이어플러그를 착용해 본적이 있다고 응답하였다. 그러나 많은 응답자들은 추후 의료진이 권장하거나(80 %), 소음으로 인한 영구적 청력손실이 발생할 수 있다는 정보를 접한다면(78.67 %) 청력보호를 위해 소음 노출 시 이어플러그를 착용하겠다고 응답하였다. 소음으로 인한 영구적 청력 손실의 잠재성과 효율적인 청력 보호 방법에 대한 체계적인 교육으로 일반인들의 소음성난청을 예방하여야 하겠다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1288-1292
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• 2007

Mobile phone is necessary articles by increasing mobile communication now. People usually use the Mobile phone in any time and place. Ring tone of Mobile phone effect owner or other person. The sound level of Mobile phone ring tone could be considered as noise if it is too loud a specific situation. Manufacturing company improve ring tone of mobile phone better in consumer's perception. In this study, we record ring tone of mobile phone and estimated the complexity and nonlinear characteristics of the relation between subjective evaluation and sound metrics. Linear regression models were obtained for the subjective evaluation and sound quality metrics. Semantic Differential Method is used to study sound quality Evaluation. To analyze the sound quality of ring tone.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.1026-1031
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• 2003

A vibration isolation system fur a large reverberation chamber (1,228㎥, 1,000ton) has been installed. The reverberation chamber generates loud noise and induces high level of vibration to perform spacecraft acoustic environmental tests. The isolation system prevents vibration transfer from the chamber to enclosure buildings. This paper describes logical design process and commissioning experiments of the system. Design criteria have been induced from rigid body model of the chamber. Finite element model has been employed to select the characteristics of rubber pads. A total of 21 rubber pads have been installed between the chamber and supporting pedestals. A sand bag of 800kg was dropped on the chamber floor to measure the natural frequency of the isolation system. Absolute transmissibility has been measured while generating 145㏈ in the chamber. The natural frequency of the chamber is 10.5㎐, which is 80% of estimated value. Overall transmissibility at working frequency range (25㎐-10,000㎐) is less than -6㏈.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.103-106
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• 2005

This paper reviews the dynamic load phenomenon referred to as 'silo quaking', caused shock vibration and loud noise, during gravity discharge in coal silos. Quaking in tall silo is examined using experimental data obtained from a Coal Power Plant and several experimental and numerical investigations available in the published literature. In the experiment, the acceleration was measured at various height on the silo column and floor and by doing so, not only could the variation of the amplitude of the quaking be observed, but also the propagation of waves could clearly be seen. Through an overview of recent research on this subject, it is shown that the current silo quaking is produced by slip-stick friction between the internal wall of silo and the granular material, i.e. coal.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.857-861
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• 2004

An active method that improves low frequency characteristics of a reverberation chamber has been proposed. Spatial uniformity of sound pressure at low frequency has been increased by applying active noise control system. The system acts as frequency selective damping materials, which decreases resonance at low frequency and leave high frequency sound field as it is. Linearity of the chamber, which is essential for sound power measurement in the chamber, is guaranteed since fixed control logic has been adopted. Simple application and tests have been done in a small sized rectangular reverberation chamber which has 400Hz cutoff, Loud speakers were used to simulate a noise source and to construct an active noise control system. The spatial distribution of a sound field at 250Hz, 315Hz and 400Hz bands has been measured before and after control. The standard deviation of sound field has been decreased from 3.4dB to 2.5dB. The results show the possibility of active control system as a sound diffuser.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 추계학술대회
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• pp.71-74
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• 1997

MR acoustic sound or noise due to gradient pulsings has been one of the problems in MRI, both in patient scanning as well as in many areas of psychiatric and neuroscience research, such as brain fMRI. Especially in brain fMRI, sound noise is one of the serious noise sources which obscures the small signals obtainable from the subtle changes occurring in oxygenation status in the cortex and blood capillaries. Therefore, we have studied the effects of acoustic or sound noise arising in fMR imaging of the auditory, motor and visual cortices. The results show that the acoustical noise effects on motor and visual responses are opposite. That is, for the motor activity, it shows an increased total motor activation while for the visual stimulation, corresponding (visual) cortical activity has diminished substantially when the subject is exposed to a loud acoustic sound. Although the current observations are preliminary and require more experimental confirmation, it appears that the observed acoustic-noise effects on brain unctions, such as in the motor and visual cortices, are new observations and could have significant consequences in data observation and interpretation in future fMRI studies.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.94-99
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• 2000

When operating NC lathe, gear box which is equipped with gear train and spindle sometimes generates loud noise and excessive vibrations. In order to identify their causes, In this study, torsional and lateral vibration characteristics including critical speeds of the gear train-spindle system are first analyzed by using torsional and lateral vibration models of the gear train and shafts. Natural frequencies and modes of the gear box structure are also analyzed by impulse hammer test. Furthermore, measured vibration and noise signals are analyzed and compared with theoretical analysis results. At last it is concluded that the cause of the excessive mise and vibration is the resonance between gear meshing frequency including its side bands, shaft bending and torsional vibration frequencies, and the natural frequencies of th gear box structure. Consequently the noise and vibration levels are greatly reduced by avoiding resonance between them through the redesign of the gear module.