• Journal of Environmental Impact Assessment
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• v.27 no.2
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• pp.105-113
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• 2018

The modeling of noise mapping and the evaluation of noise pollution based on the exposed population were frequently used as an indicator of environmental noise assessment to overcome the limitations of field survey and Tele-Monitoring System. Results from these methods were highly influenced by the setting of noise source, input data of prediction factors and analytical methods of predictive values. The population exposed to noise were estimated as M1-1>M2-1>Base>M2-2>M1-2 in both areas. The highest noise setting methods(M1-1, M1-2) were overestimated, being compared with the Base method.

• Journal of Environmental Health Sciences
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• v.27 no.4
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• pp.99-105
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• 2001

도로교통소음은 많은 지역에 산재해 있으며 특히 주도로변에 거주하는 사람들에게 환경과 관련하여 매우 중요하다. 도로교통으로부터 소음수준을 계산하는데 몇가지 다른 방법들이 이용되고 있다. 이 방법들은 계산방법과 그래프식 그리고 컴퓨터 모델링 기술 등이다. 교통과 교통소음의 영향으로부터 소음을 계산하는 간단한 기술의 예측방법은 여기에 나타내었다. 이 TNS (traffic Noise Screening) 방법은 서로 다른 도로유형에 대한 일련의 도로교통소음레벨의 예측그래프로 전개된 것이다. 이 그래프는 Federal Highway Administration (FHWA) STAMINA 2.0을 이용하여 다양한 시나리오에 대한 소음 예측모델을 계산한 결과를 기초하였다. TNS에 도로의 기하학적 형태, 교통량 주행속도 그리고 도로중앙선의 거리등의 데이터를 입력시킨다. TNS 그래프는 소음영향과 연관된 교통소음예측에서 사용하는 경우 교통소음레벨의 계산을 쉽게 한다. 이 TNS 방법은 STAMINA 2.0과 같은 상세 모델링을 대신하지는 못하지만 상세 모델을 필요로 할 때 도움을 주는 도구이다 만약 소음계산들이 중요하거나 또는 시나리오가 보다 복잡하고 부가된다면 보다 상세한 모델링이 수행되어져 스크린 결과들이 나타난다.

• The Journal of the Acoustical Society of Korea
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• v.41 no.4
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• pp.397-409
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• 2022

A model is developed for the calculation of sea surface generated ambient noise in the range dependent ocean environment. The sources are located in the horizontal plane all around and their depths are at the near-surface. The receiver array is located in the range dependent ocean waveguide. One-way coupled mode method is used to model the acoustic propagation between the sources and receiver in the range dependent waveguide, and the cross spectral density matrix of noise is derived. In simulation, noise intensity, beamforming result and coherence function are calculated from the cross spectral density matrix. These results are compared with those in the range independent environment. The modeling result shows the effect of the vertical directionality and asymmetry characteristics of the horizontal plane.

• Proceedings of the Korean Society of Computer Information Conference
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• 2013.07a
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• pp.373-374
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• 2013

대용량 공간DB에 저장된 자료에 대한 접근과 관리에 대한 복잡성을 해결하기 위하여 공간자료와 비공간 자료에 대한 사항들을 구축하고 활용할 필요가 있다. 이에 공간 개체의 공간적 요소와 비공간적 요소를 함께 관리하는 가설현장의 소음관리를 위한 시스템에서도 공간 개체에 대한 데이터의 모델링이 필요하다. 따라서 본 논문에서는 가설현장에서 소음에 따른 피해를 줄이기 위한 방벽 등의 설치를 위해 필요한 소음 시뮬레이션 시스템을 위한 모델링에 관해 연구한 결과를 제시한다.

• The Journal of the Acoustical Society of Korea
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• v.37 no.3
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• pp.129-138
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• 2018

In port and coastal areas where ship traffic is frequent, ship noise dominantly influences underwater noise in low frequency band below 1 kHz. In this paper, we propose a modeling method to estimate the underwater shipping noise using the voyage information of ship observed in AIS (Automatic Identification System). For the purpose of ship noise modeling, the navigation information of the vessels operating in the southern part of Jeju was observed using AIS and underwater noise was measured by installing a hydrophone in the experimental area to verify the modeled ship noise. AIS data were used to model the noise level of ship and compared with measured underwater noise. The variation of noise level with time was found to be similar, and the cause of the error was discussed. Through this study, it was confirmed that the noise level of ship can be estimated within 5 dB error range using AIS data.

• The Journal of the Acoustical Society of Korea
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• v.38 no.4
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• pp.378-386
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• 2019

Unlike ship noise that radiates from moving ships, wind noise is caused by breaking waves as a result of the interaction between the wind and the sea surface. In this paper, WNL (Wind Noise Level) was modeled by considering the noise source of the wind as the bubble cloud generated by the breaking waves. In the modeling, SL( Source Level) of the wind noise was calculated using the wind-speed data measured from the weather buoy operated in the coastal area of the East Sea. At the same time as observing the wind speed, NL (Noise Level) was continuously measured using a self-recording hydrophone deployed near the weather buoy. The modeled WNL according to the wind speed and the measured NL removing the shipping noise from the acoustic raw data were compared in the low-frequency band. The overall trends between the modeled WNL and the measured NL were similar to each other. Therefore, it was confirmed that it is possible to model the WNL in the shallow water considering the SL and distribution depth of bubble cloud caused by the wind.

• Proceedings of the IEEK Conference
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• 2003.07e
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• pp.2479-2482
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• 2003

능동소음제어 시스템에서 많이 사용되어 온 적응 알고리듬은 filtered-X LMS (FXLMS) 알고리듬으로, 이 알고리듬에서의 수렴속도는 필터링 된 신호에 의해서 좌우되기 때문에 FXLMS 적용시 실제 수렴성능이 저하되거나 수렴이 안 되는 경우도 발생할 수 있다. 본 논문의 목적은 변환영역에서 능동소음제어 시스템의 2차 경로 모델링을 행함으로써 전체 능동소음제어 시스템 동작의 수렴성능을 향상시키려는 것이다

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1994.04a
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• pp.88-93
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• 1994

본 연구에서는 배기계의 진동해석과 관련하여, 배기계 파이프에 대한 보 모델링기법을 제안하였다. 굴곡부가 통상의 직석보로 모델링될 때는 실제보다 고유진동수가 상당히 높게 평가되므로, 이 굴곡부의 강성을 적절히 수정해 주어야만 한다. 따라서 본 논문에서는 정적 변형에너지개념을 이용하여 실제 엔지니어들이 사용할 수 있을 정도로 간단하면서도, 합리적인 기법을 제시하였다. 실제 배기계의 중앙파이프의 진동해석에 적용해 본 결과 이 기법의 타당성과 효율성을 입증할 수 있었다.

• Journal of the Korean Society for Railway
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• v.16 no.3
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• pp.175-182
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• 2013

Rolling noise is an important source of noise from railways; it is caused by wheel and rail vibrations induced by acoustic roughness at the wheel/rail contact. To reduce rolling noise, it is necessary to have a reliable prediction model that can be used to investigate the effects of various parameters related to the rolling noise. This paper deals with modeling rolling noise from wheel and rail vibrations. In this study, the track is modeled as a discretely supported beam by regarding concrete slab tracks, and the wheel vibration is simulated by using the finite element method. The vertical and lateral wheel/rail contact forces are modeled using the linearized Hertzian contact theory, and then the vibration responses of the wheel and rail are calculated to predict the radiated noise. To validate the proposed model, a field measurement was carried out for a test vehicle. It was found that the predicted result agrees well with the measured one, showing similar behavior in the frequency range between 200 and 4000 Hz where the rolling noise is prominent.

• Journal of KSNVE
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• v.26 no.2
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• pp.10-17
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• 2016