• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.663-665
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• 2007

생산시설에서의 소음원은 여러 가지가 있으나 증기 방출시 발생되는 소음은 대기 중에 직접 노출되기 때문에 증기 방출시 소음저감을 위한 사이렌서의 설치가 필요하다. 스팀 사이렌서는 습기와 고온에 항상 노출되기 때문에 일반적인 흡음 및 차음재료의 사용에 제한이 있다. 본 연구에서는 스틸 울과 스틸 타공판으로 구성된 사이렌서와 사이렌서를 둘러싸는 외부 용기로 구성된 스팀 사이렌서를 대상으로 소음저감성능을 평가하였다. 스팀 방출시 소음 저감 성능을 평가하여야 하지만 사이렌서 내부에서 스팀이 방출되는 조건에서의 실험에 어려움이 있어 스팀사이렌서의 내부에 라우드 스피커와 마이크로폰을 설치하여 스팀사이렌서 내부에서 발생되는 음압레벨을 측정하였다. 또한 소음이 표면에서 1m 이격된 지점에서의 소음레벨을 측정하여 소음저감성능을 평가하였다. 소음 저감성능 평가 결과 500 Hz 이상 주파수 범위에서 약 40 dB이상의 소음저감성능을 확인하였다.

• Science of Emotion and Sensibility
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• v.22 no.3
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• pp.47-54
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• 2019

We examined previous studies of the correlation analysis of heart rate variability as a method to reduce the stress caused by outside noise during driving, and we investigated whether there are electrocardiographic changes when drivers play music, which provides a stable sound source amid the noise. Because the number of cars increases every year, drivers and passengers show an increase in stress caused by outside noise. The stress from outside noise while a person is driving can cause several disorders, such as anxiety, immunosuppression, depression, and heart disease. Subjects in this study operated a vehicle simulator to reduce the stress from outside noise and were given different auditory stimuli, and we studied the drivers' responses to the stimuli. Repeated-measures analysis of variance revealed a significant differences between subjects exposed to different auditory stimuli (ρ < 0.05). Through post hoc analyses, we examined these differences. We found significant differences between factor 1 (stability) and factor 2 (simulation driving), between factor 1 (stability) and factor 3 (driving + police siren), and between factor 1 (stability) and factor 4 (driving + police siren + music). In addition, the factor that produced the highest level of sympathetic nervous system activity was factor 4 (driving + police siren + music), followed by factor 3 (driving + police siren), factor 2 (driving), and factor 1 (stability). In conclusion, even when a police siren was heard during driving, there were no significant differences on electrocardiograms (ECGs). In addition, even when the siren was heard over the music, there was no difference on the ECGs (ρ < 0.01). In future studies, investigators should determine which types of music help stabilize the heart rate during driving.

• Journal of the Korean Institute of Telematics and Electronics
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• v.16 no.5
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• pp.34-41
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• 1979

In the work reported here we have sputtered from silicon targets in argon-silane mixtures using undoped n-type and p-type targets. Doped films have been produced, but the doping efficiency is extremely low. It appears that the dopant atoms are able to satisfy their natural valencies and are therefore not electrically active. Infra-red absorption spectroscopy has been used to establish the hydrogen bonding in the films. No correlation has been found between the nature of the hydrogen bonding in the film and the electrical properties.

• Electric Engineers Magazine
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• v.229 no.9
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• pp.10-15
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• 2001

사이렌, 벨이나 소리를 발생하는 다른 장치들은 침입자에게 겁을 주는 방해물의 역할을 한다. 하지만 만약에 우리가 집에 있지 않을 때 침입자가 집을 떠난 후에는 누가 경보 회로를 리셋시킬 것인가?

• Journal of Broadcast Engineering
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• v.20 no.6
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• pp.827-836
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• 2015

The purpose of this study is to suggest improvement direction of the delivery system through researching the information accepter' recognition and use about warning delivery system. According to the survey, they listen to civil defence alert broadcasting on mass media more than personal media. The frequency of alert broadcasting is significantly very low and they listen to it below 5 times in a year. Also, nearly one in four people says its siren and contents are indistinct. Alert broadcasting's siren shows less memory retrieval and sorting capability than others and the result shows that they will act based on the broadcasting instead of reacting to prior knowledge in real situations. Finally, the result shows that improving public awareness through education and publicity more than social system buildup is important in civil defence alert system.

• Fire Science and Engineering
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• v.23 no.5
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• pp.153-160
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• 2009

This study aims to review the propagation characteristics of fire alarm sound in building through computer simulation. In order to achieve this goal, the sound power level of existing three different emergency alarms were measured in an anechoic chamber. Sound power level of alarm bell was 98.6dB and electronic-siren speaker was 95.7dB, and electronic-siren phon was 101.8dB at the voltage of DC 24V in the condition of anechoic chamber. As the results of acoustic simulation, it was shown that sound levels at the corridor of the building were relatively high and even. But, there were large difference in sound level at all the frequency bands between corridor and lecture rooms. This mean that alarm sound couldn't be recognized sometimes in lecture rooms. Through the computer simulation, the propagation characteristics of fire alarm sound could be forecasted and compared due to plans of buildings.

• The Journal of the Convergence on Culture Technology
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• v.9 no.1
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• pp.153-160
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• 2023

This research experiments on the workers' recognition of the fire alarm sound for sirens and portable loudspeakers in a small construction site. As a result of analyzing the siren alarm sound recognition from measuring on the 1st, 2nd, and 4th floors, the sound was more unrecognizable on the 4th floor than on the 1st, and 1 person on the 1st floor was unable to recognize all sounds. In the case of the 2nd floor, one person could not notice the alarm in the last 3rd trial, and another did not realize it all three times. For the 4th floor, 3 people demonstrated unrecognition in all 3 tests. As a result of analyzing the recognition of portable loudspeaker alarm sounds, 1 person could not recognize all sounds on the first floor. In the case of the 2nd floor, 2 people were confirmed to be unable to notice, and lastly, 4 people could not recognize all trials on the 4th floor. The subjects who didn't recognize the sound were unable to distinguish between portable loudspeaker alarm sound and work noise due to the workspace and obstacles.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1293-1294
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• 2010

• 월간산업보건
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• s.385
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• pp.38-39
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• 2020

영화 <힘을 내요, 미스터 리>에서 주인공 철수(차승원 분)는 한때 소방관이었다. 그러나 불의의 사고를 당해 정신지체를 갖게 되면서 소방관을 그만 두고 만다. 치명적인 위험 속으로 뛰어드는 소방관들이 가장 많이 앓는 질병으로 난청이 있다. 출동 시 사이렌이 울리는 등 심한 소음을 들을 수밖에 없기 때문이다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.805-808
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• 2008

In this paper, it was performed the analysis on various intersection acoustic patterns for detection rate improvement of accident sound detection system : an acoustic pattern analysis on general traffic noise, an acoustic pattern analysis on engine noise, an acoustic pattern analysis on obstruct factors for accident sound detection system. There are remarkable differences between the acoustic patterns of traffic noise and accident sound, and we most consider the acoustic patterns when we compose the accident traffic detection system by acoustic because there is error range of 20[dB] according to the volume of traffic in intersection.