• 한국철도학회논문집
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• 제10권3호
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• pp.278-283
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• 2007

Community noise, especially a rail traffic noise has been serious social issues in Korea. Our society needs practical tools to reduce noise levels for public who live near the railway lines. This paper proposes a noise reducer for railway traffic noise. At the beginning, various types of reducers are discussed, with the advantages and disadvantages with respect to acoustical phenomena. Then, the acoustic effects are discussed based on an insertion loss measurement. After several types of reduces are installed at fields, the noise level is monitored with and without the reducer. The result shows that the proper selection of reducers affects the noise level by 6 dB. The statistics of the mean and a standard deviation turns out to be 3.2 dB and 0.8 dB, respectively. Noise reducers are strongly recommended for the place where apartments are densely constructed alone the railway. Installation of noise reducers seems to be an effective and practical solution for the community traffic noise reduction.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.376-379
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• 2006

Traffic noise in Seoul has critical issues in community. In this paper, various noise barriers and reducers has been evaluated.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.388-391
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• 2006

The use of noise barrier is being increased to reduce the environmental noise in these days. Also, many noise reducers installed at the top of noise barrier are developed for improving the performance of noise reduction. So we evaluate the performance of the noise reducers and compare the results. Results of the field tests show that the insertion loss due to the noise reducers is up to 10.6 dB.

• 한국소음진동공학회논문집
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• 제17권12호
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• pp.1139-1144
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• 2007

The use of noise barrier is being increased to reduce the environmental noise in these days. Also, many noise reducers installed at the top of noise barrier are developed for improving the efficiency of noise reduction. So we evaluate the performance of the noise reducers and compare the results among the others. Results of field tests show that the insertion loss due to the noise reducers is up to 10.6 dB.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 추계학술대회 논문집
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• pp.570-574
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• 2013

The use of noise barrier is being increased to reduce the environmental noise in these days. Also, many noise reducers installed at the top of noise barrier are developed for improving the efficiency of noise reduction. So we evaluate the performance of the noise reducers and compare the results among the others. Results of field tests show that the insertion loss due to the noise reducers is up to 10.6 dB.

• 한국소음진동공학회논문집
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• 제17권3호
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• pp.207-212
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• 2007

Community noise has been great concerned in public. The traffic noise in seoul, especially has been growing awareness for the quiet living environment. In this paper, the effect on the noise barrier in order to reduce highway noise near on the street has been examined. First barriers have been evaluated at 5 locations in the city. The evaluation is performed before and after construction, with the reference point which does not affected on road traffic volume. Then, noise reducers mounted on the harriers also have been examined. the result shows that it reduces noise level by $3{\sim}3.5dB(A)$ with a standard deviation of 2.8 dB(A).

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.91-98
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• 2007

Community noise has been serious social issues in Korea. This paper reviews current statistics and status on railway noise, with practical engineering tools in order to reduce the noise level from railway traffic noise sources. At the beginning, guidelines of the current environmental policy are discussed, with the new policy on railway noise to be enforced beginning in 2007 with 5 year schedule. Then, a noise reducer is proposed as a tool to reduce noise levels protecting people living near at the railway. Details on the acoustic effect in field test are discussed with the result of implementation in the street. We propose noise reducers as an effective and practical tool for the people who are exposed to rail traffic noise in cities.

• 한국소음진동공학회논문집
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• 제20권9호
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• pp.791-796
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• 2010

Installing noise barriers is the most common method for reducing the highway traffic noise to the road side residential area. After the report about edge potential concept of a noise barrier, various types of noise reducing devices(NRDs) called "noise reducers" have been suggested for getting more shielding effect on the top of highway noise barriers. But, it has been doubtful about effect of the NRDs in field because there was no appropriate and unified method to estimate the acoustic performance by using field measurement of the NRDs in Korea. In this study, the authors have considered to setup a practical method to test and estimate the acoustic performance of NRDs. For eliminating the noise reduction effect of the NRDs height itself, the source and measuring points are adjusted as highly as the NRDs height. For the frequency weighting in the estimation of the NRDs effect, the highway noise spectra were measured at asphalt and concrete road side and then averaged for a unit spectral parameter.

• 한국멀티미디어학회논문지
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• 제5권2호
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• pp.147-157
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• 2002

영상 시퀀스에 포함된 잡음은 화질을 열화시키고 중요한 영상의 미세 정보를 훼손시킨다. 또한 잡음은 영상의 복잡성을 증가시키므로 영상의 압축효율을 저하시킨다. 본 논문에서는 특성이 서로 다른 두개의 적응형 잡음제거 필터를 결합적으로 연결하여 잡음을 제거하는 공간결합필터와 시간결합필터를 제시하고, 이 결합필터들을 연결한 IIR필터 구조를 갖는 3차원 잡음제거 필터를 제시한다. 제시된 잡음제거 필터는 영상의 에지와 미세정보를 유지하면서도 평탄한 영상영역에 대해서는 강한 잡음제거를 수행하며 이웃한 프레임 사이에서도 잡음에 의한 시간적인 깜박임을 억제한다. 실험결과 제안된 잡음제거 필터는 기존 방식들에 비하여 객관적 화질뿐만 아니라 주관적인 화질을 크게 향상시킴을 알 수 있었다.

• 한국생산제조학회지
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• 제20권6호
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• pp.830-836
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• 2011

Most of pitch/yaw reducers consist of several planetary geartrains. Planetary geartrains make gearboxes to be small and light, low noise and good efficiency. Most important thing in the planetary geartrain is load distribution on the gear tooth flank. In this study, the effect of output shaft bearings on the load distribution of gear tooth flank has been investigated. The commercial software was employed to compare the load distribution of two models depending on the bearing type. The spherical roller bearing(SRB) and the cylindrical roller bearing(CRB) were used as output shaft bearings in the $1^{st}$ model, and two taper roller bearings(TRB) were used in the $2^{nd}$ model. As a result, it was found that the $2^{nd}$ model. showed better performances on the load distribution of gear tooth flank, this results stated that the output shaft bearing system could be important consideration when designing reducers for wind turbine systems.