• 설비공학논문집
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• 제19권6호
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• pp.476-484
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• 2007

Recently, in accordance with the buildings are becoming to large-sizes, high-stories, the large scaled facilities and equipments in machine room are quite demanding, and the generated noise volume according to this situation is on increasing. Since such noise is becoming to the object of a serious civil appeal, it is the real situation that a reduction countermeasure against the machine room equipment noise is keenly necessitated. On such viewpoint, this study has recorded, measured the noises which were generated from each individual as same as the whole equipped machines and tools, on the object of the dormitory machine rooms of the 3 colleges that haying mutually different peculiarities, then after grasp-ing their characters and acoustic powers, this research has verified its prediction possibility and the authenticity by comparison the estimated numerical value with the actually measured numerical value through the acoustic simulation. After grasping the prediction possibility in such way, by utilization of the sound absorption material in the machinery room, from the stage of design, the soundproof measures for the noise reduction at machine room could be regulated effectively, and it is also considered that such data would be utilized as the fundamental material for an establishment of the measure for sound insulation.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.630-636
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• 2008

1000MW급 증설과 관련하여 발전소 주변지역으로부터 민원이 제기된 3000MW급 화력발전소는 넓은 평지에 위치하여 발전소의 영향이 그대로 주변지역에 전달되는 상태임에도 일상 소음레벨이 환경 기준치를 만족하는 상태였으나 향후 증설에 따른 소음도 증가에 대비하여 소음영향을 예측하고 저감 대책을 검토하였다. 대형 화력발전소의 옥외소음원은 Booster fan, I.D.fan, 주변압기, 대형 철탑, 해수순환수 펌프 전동기, 증기방출관 등이 있다. 대상 주거지역의 경우는 대형팬에 의한 지향성이 크게 나타났다. 따라서, 발전소가 주변지역에 주는 소음별 기여도를 평가하고 영향이 큰 대형팬에 대한 대책으로써 기기주변에 방음벽을 설치하는 방안과 함께 소음원의 크기를 저감시킬 수 있는 소음기 대책을 추천하여 증설 예정호기를 비롯한 기존 호기중 주거지역에 영향이 큰 3000MW에 대하여 수립함으로써 소음저감 목표치를 달성하는 결과를 도출하였다.

• 한국도로학회논문집
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• 제15권6호
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• pp.61-68
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• 2013

PURPOSES : The purpose of this study is to study the noise reducing effect of Micro Surfacing by comparing general asphalt, longitudinal tining and Slurry Seal. METHODS : This study measures vehicles' noise of each section by the NCPX method that can measure noise between the road surface and the tire at the field. Total sound pressure and sound pressure level by the 1/3 octave band frequency are calculated through the field data of each section. Total sound pressure level is compared by ANOVA test statistically. After ANOVA test, post-hoc test is conducted to know mean difference of surface type by Tukey. RESULTS : As the result of CPB analysis to confirm sound pressure levels by frequency, it was shown that sound pressure levels by frequency are totally similar except for those of frequency bands between 100Hz and 500Hz. The result of ANOVA test and post-hoc test, it was shown that sections of surface type have a difference. The result of Micro Surfacing was lower 2~5dB(A) than other surface type. CONCLUSIONS : It is found that the noise reduction performance of Micro Surfacing was better than other surface type.

• 한국정보통신학회논문지
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• 제21권6호
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• pp.1167-1173
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• 2017

영상처리는 사회가 고도의 디지털 정보화 시대로 발전함에 따라 응용분야가 점차 다양해지고, 중요한 분야로 각광 받고 있다. 그러나 영상 데이터는 전송하는 과정에서 여러 원인으로 열화가 발생하며 주로 salt and pepper 잡음이 대표적이다. salt and pepper 잡음을 제거하기 위한 대표적인 방법에는 CWMF, SWMF, A-TMF가 있으며 기존의 방법들은 salt and pepper 잡음 환경에서 잡음 제거 특성이 다소 미흡하다. 따라서 본 논문에서는 salt and pepper 잡음을 제거하기 위해 잡음 판단 후, 중심화소가 비잡음인 경우 원 화소 그대로 보존하고, 잡음인 경우, 국부 마스크의 잡음밀도에 따라 2차원 스플라인 보간법 및 메디안 필터를 적용하여 처리하는 알고리즘을 제안하였다. 그리고 객관적 판단을 위해 기존의 방법들과 비교하였으며, 판단의 기준으로 PSNR(peak signal to noise ratio)을 사용하였다.

• 환경정책연구
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• 제8권2호
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• pp.63-82
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• 2009

도로, 철도, 공항을 포함하는 교통시설에 의한 교통소음으로 인하여 많은 사람들이 신체적 및 정신적인 피해를 받고 있는 가운데 선진국의 경우 교통소음에 노출된 인체 건강의 위험성을 인지하고 그것을 해결하기 위한 많은 연구가 수행되고 있다. 이러한 연구흐름에 따라 본 연구에서는 교통소음의 건강영향에 대한 국내외 연구결과를 바탕으로 하여 국내 교통소음에 의한 건강위해성을 평가할 수 있는 기본적인 방안을 모색해 보고자 한다. 교통소음의 건강영향에 대한 평가방법 중에서 많은 연구가 진행되고 있는 교통소음에 의한 성가심 및 수면방해 연구는 교통소음의 측정자료 및 설문조사결과를 바탕으로 소음지표에 대한 불쾌감 및 수면방해 호소비율의 관계를 보여주고 있다. 이에 대한 국내외의 노출-반응 예측결과를 비교해 보면 우리나라 사람들이 다른 나라 사람들보다 교통소음에 대해 대체로 더 높은 소음성 불쾌감 및 수면방해를 호소하는 것을 알 수 있다. 교통소음의 건강영향에 대한 연구결과 및 외국의 사례를 바탕으로 교통소음의 건강위해성을 평가할 수 있는 기본적인 방안을 제시하였는데 그에 대한 내용은 국내 교통소음 건강영향 예측모델의 개선을 통한 객관적인 평가기준 마련과 아울러 교통소음에 대한 사람들의 인식정도나 소음환경의 질을 향상시킬 수 있는 저감방안 마련을 포함한다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 춘계학술대회 논문집
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• pp.808-813
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• 2011

There are hundreds of thousands call center workers wearing acoustic device. However, researches and noise exposure measurements on the noise transmitted from acoustic devices have seldom been performed due to the difficulty of measurement and to the absence of the measuring method in Korea. The aim of this study is to set up management measures to protect hearing loss on the call operator by acquiring measurement data of noise transmitted from the headset Noise exposure measurements of 17 operators were performed in 7 call centers and Head and Torso Simulator method in compliance with the ISO Standard 11904-2 was used for the measurement of noise transmitted from the headset Sound pressure levels(SPL) transmitted from the headset were 73.2~86 dB(A). The operator exposed to the highest SPL set up his volume control at 9 which was the highest volume level. The volume control level, adjustable from 1 to 9, could be identified 12 out of 17 operators and the range of volume levels was 4.5~9. As a result of Pearson Correlation Analysis, the correlation between volume level and SPL transmitted from the headset showed high relation as significance at the 0.672 level(p<0.05). To protect hearing loss of call center operators, it is more practical and effective measure to limit the volume level below the noise exposure level, i.e. 85 dB(A), rather than to carry out noise monitoring considering cost-effective aspect.

• Journal of Preventive Medicine and Public Health
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• 제27권2호
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• pp.286-298
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• 1994

For the purpose of presenting the basic data for the establishment of control measures on the long-term noise exposed workers, this study was carried out on the relationship between personal noise exposed dose and hearing loss on the 67 male workers whose hearing threshold had exceeded 40 dB in 4,000 Hz, from 1990 to 1992. Conclusively, the level of hearing loss was significantly related to personal noise exposed dose in follow-up period. We considered that personal noise exposed dose which was measured by the personal noise dosemeter was more efficient rather than the noise level of workplace for the evaluating the long-term change of hearing acuity. And although in the case of not-diagnosed as noise induced hearing loss. it was suspected that the active control programs such as improvement of noisy environment or early transfer to proper workplace were needed on the workers who exposed with over 90 dB in personal noise exposed dose.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.212-217
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• 2000

This first ISO/CD 7475 is a proposed revision of ISO 7475-1984, which specifies requirements for enclosures and other safety measures used to minimize mechanical hazards produced by the rotor in the measuring station of centrifugal (rotational) balancing machines. The hazards are associated with the operation of balancing machines under a variety of rotor and balancing conditions. This standard defines different classes of protection that enclosures and other protective features have to provide and describes the limits of applicability for each class of protection. At the meeting held at AFNOR in Paris in June 1999, ISO/TC 108/SC1/WG 12 agreed to prepare a first ISO Committee Draft (CD) and circulate to the member bodies for vote and comment by 3 March 2000 since publication as an International Standard requires approval by at least 75% of the member bodies casting a vote. The results of the ballot on this first ISO/CD 7475 was positive so that it will be prepared as an ISO/DIS (ISO/DIS 7475) and discussed in a meeting of ISO/TC 108/SC1 at BSI, London, u.K. in March 2000. Contents of this ISO/CD 7475 with some member comments accounted is briefly described in what follows.

• 융합신호처리학회논문지
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• 제2권4호
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• pp.53-58
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• 2001

이동전화망을 위한 신뢰성 높은 객관적 통화품질평가 척도개발을 위하여 Bark Spectral Distortion Perceptual Speech Quality Measure의 성능을 분석하여 이 척도들을 실제 환경에서 수집된 음성 데이터에 대해서 실험한 결과, 성능의 저하가 나타났다. 본 논문에서는 인간의 심리음향학적 특성인 마스킹을 적용하는 방안을 제안하여 그 유효성을 실험으로 확인하였다. 이때, masking threshold 계산에 tone 신호를 사용하기 때문에 음성신호에 대하여 계산할 경우 문제점이 있을 수 있으므로 scaling 을 적용하는 새로이 제안하였다. 디지털 이동통신망에서 수집된 음성 데이터에 대한 성능평가 결과, 기존의 척도들 보다 더 높은 성능을 보임을 확인하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.332-339
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• 2007

As the economy has grown and the main industry in Korea has been changed from secondary industry to tertiary industry, the importance of indoor environment has been a matter of common concern, in which one of the main concerns is to improve the indoor acoustic conditions. However, even though this is required more than before, there are no measures to protect the human being from the noise of electric home appliances. This is owing to the absence of the data about sound power level of electric home appliances. So, we investigate the sound power level of them and analyze the acoustical characteristics of each one. First, we tried to investigate the sound power measurement method of each electric home appliance. After it we test the sound power level of them. From the survey, we can know that the vacuum cleaner is the most noisy electric home appliance, and the refrigerator is the least noisy one. The noise of a range hood is distributed over a wide range frequency. Lastly, we intented to propose the proper method measuring sound power level on each electric home appliance.