• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2002년도 학술대회지
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• pp.535-538
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• 2002

크랙 실링 자동화 장비의 비젼 시스템은 도로면의 영상을 획득하고 이를 컴퓨터로 처리하여 도로면의 랙을 탐지, 분석 및 맵핑하는 역할을 수행하는 것이다. 그러나 실제 도로에는 크랙과 함께 오일 자국, 타이어 자국, 차선, 기 실링된 크랙 등의 수많은 노이즈들을 포함하고 있기 때문에 비젼 시스템을 통해 얻어진 노이즈가 포함된 도로면 영상을 기반으로 크랙을 자동으로 탐지하고 맵핑하는 것은 매우 어려우며 이러한 노이즈는 크랙의 정확한 탐지 및 맵핑의 커다란 방해 요소이기 때문에 이들의 제거가 선결되어야만 한다. 따라서 본 연구에서는 획득된 도로면 영상으로부터 크랙을 탐지하고 맵핑하기 이전에 실링되어질 크랙을 정확히 인지(recognition)하기 위한 노이즈 제거 알고리즘을 제안하고자 한다.

• Nuclear Engineering and Technology
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• 제52권10호
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• pp.2250-2261
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• 2020

Accurate localization of radioactive materials is crucial in homeland security and radiological emergencies. Coded-aperture gamma camera is an interesting solution for such applications and can be developed into portable real-time imaging devices. However, traditional reconstruction methods cannot effectively deal with signal-independent noise, thereby hindering low-noise real-time imaging. In this study, a novel reconstruction method with excellent noise-suppression capability based on a multi-layer perceptron (MLP) is proposed. A coded-aperture gamma camera based on pixel detector and coded-aperture mask was constructed, and the process of radioactive source imaging was simulated. Results showed that the MLP method performs better in noise suppression than the traditional correlation analysis method. When the Co-57 source with an activity of 1 MBq was at 289 different positions within the field of view which correspond to 289 different pixels in the reconstructed image, the average contrast-to-noise ratio (CNR) obtained by the MLP method was 21.82, whereas that obtained by the correlation analysis method was 5.85. The variance in CNR of the MLP method is larger than that of correlation analysis, which means the MLP method has some instability in certain conditions.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2007년도 정기학술발표대회 논문집
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• pp.392-395
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• 2007

도심의 과밀화 등으로 재건축 및 재개발의 활성화, 대규모 택지개발에 의한 신도시 개발, 사회기반시설 확충 등의 증가로 건설폐기물이 급증과 더불어 도심지내 공사장 등에 의한 소음 발생원이 지속적으로 증가하고 다양화됨에 따라 소음${\cdot}$진동관련 환경 분쟁 및 민원이 급증하고 있는 추세이다. 이에 따라 정부는 생활주변의 정온한 환경을 조성하기 위하여 2009년 1월부터 공사장소음규제기준을 현재 70dB에서 65dB로 상향 적용하여 건설공사 관련 환경분쟁 및 민원의 발생이 더욱 증가할 것으로 예상된다. 본 연구에서는 1) '건설공사장 간이 소음 예측 프로그램'을 통한 현장파쇄시설의 소음레벨 예측값과 현장에 설치운영중인 현장파쇄시설의 실측 소음레벨을 비교${\cdot}$분석하여 현장파쇄시설의 소음레벨을 분석하였다. 2) 건설공사 현장에서 현장파쇄시설을 적용하고자 할 경우 소음에 의한 환경 분쟁 및 민원 발생의 최소화 방안을 수립하고자 한다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.171-174
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• 2007

During last 30 years, Korea economy has grown so fast and many leading-edge technologies ware introduced from the advanced countries. but this fast growth inevitably produced imperfect completion of infrastructures and caused man-made catastrophes like Sungsu Bridge and Sampoong Department Store. After the incidents, Korea Government and National Assembly established "The Special Law for Safety Maintenance of Infrastructures". According to this law, most of infrastructures must be inspected periodically. During last 10 years after the establishment of the law, many infrastructures were improved and the quality of construction was upgraded. However, important and weak-to-disaster infrastructures need to be watched continuously. Many monitoring technologies were developed and tested in the field. In this paper, the new research project "Establishment of Testbed of Safety Management Network for Main Infrastructures", funded by government, was introduced.

• 대한산업공학회지
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• 제37권4호
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• pp.350-357
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• 2011

In the recent, it is gradually important for airport to consider environmental aspects as sustainable development is emerged. ICAO, FAA and individual countries has tried to reduce airport noise and pollution. Thus, the effort is needed to incorporate environmental factor into productivity indicator of airport. Our paper use DEA method with the non-parametric directional output distance function(DDF) to assess productivity of 14 airports in Korea during 2008~2010. In addition to three inputs, two conventional outputs, two undesirable outputs have been considered : noise and air pollution. Results are compared from models that do not include undesirable outputs. Inclusion in the analysis of the undesirable effects of airport operations leads to greater and closer airport's efficiency scores.

• 대한안전경영과학회지
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• 제17권3호
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• pp.377-381
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• 2015

For the first time, PLL frequency synthesizer using DDS was adapted for the data link communication system which should fast transmit and receive each other with the correct information and fast Hopping System. It is inevitable to lost the synchronization by slow lock time about PLL and no cut off the noise. This paper propose the design of PLL frequency synthesizer which can make 800MHz frequency range. The PLL frequency synthesizer has three high qualities those are frequency accuracy, fast lock time and outstanding phase noise.

• 전력전자학회논문지
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• 제26권3호
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• pp.176-182
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• 2021

This research proposes a high-frequency circuit that can accurately predict the differential mode noise of single-phase inverters at the circuit design stage. Proposed single-phase inverter high frequency circuit in the work is a form in which harmonic impedance components are added to the basic single-phase inverter circuit configuration. For accurate noise prediction, parasitic components present in each part of the differential noise path were extracted. Impedance was extracted using a network analyzer and Q3D in the measurement range of 150 kHz to 30 MHz. A high-frequency circuit model was completed by applying the measured values. Simulations and experiments were conducted to confirm the validity of the high-frequency circuit. As a result, we were able to predict the resonance point of the differential mode voltage extracted as an experimental value with a high-frequency circuit model within an approximately 10% error. Through this outcome, we could verify that differential mode noise can be accurately predicted using the proposed model of the high-frequency circuit without a separate test bench for noise measurement.

• 수산해양기술연구
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• 제53권4호
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• pp.413-422
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• 2017

The objective of this study was to prove possible effects of a habitable place for fish around semi-submersible drilling rig which measured underwater radiated noise, irradiance distribution of rig's light and conducted experimental fishing in Malaysia territory and observed for distribution of fishes around the rig by ROV during drilling operation in the East Sea of Korea. As a result underwater radiated noise was $130dB/{\mu}Pa$ from 156.25 to 187.50 Hz, irradiance distribution of light was between 21.5 and 43.1 lx. Despite this result, underwater radiated noise was not a threat to fish around rig and low irradiance distribution of light also played a role in the luring influence of the fishes at night. Fish showed up in the beginning of drilling operation and at the end of drilling operation. However, there are few fish in the midst of drilling operation. The main reason for this result was the destruction of the habitable place due to blow out mud and broken pieces of ground formation in drilling hole. The results are expected to contribute to reasonable fishery management around rig.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권8호
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• pp.2866-2880
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• 2014

We propose a video denoising method based on Kalman filter to reduce the noise in video sequences. Firstly, with the strong spatiotemporal correlations of neighboring frames, motion estimation is performed on video frames consisting of previous denoised frames and current noisy frame based on intensity and structure tensor. The current noisy frame is processed in temporal domain by using motion estimation result as the parameter in the Kalman filter, while it is also processed in spatial domain using the Wiener filter. Finally, by weighting the denoised frames from the Kalman and the Wiener filtering, a satisfactory result can be obtained. Experimental results show that the performance of our proposed method is competitive when compared with state-of-the-art video denoising algorithms based on both peak signal-to-noise-ratio and structural similarity evaluations.

• 품질경영학회지
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• 제44권4호
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• pp.935-949
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• 2016

Purpose: This study attempts to find out the optimum condition of the rotary cutter making pellet in the footwear outsole process. The pellets are used in the process of outsole rubber fabrication to reduce cycle time and save raw material. Methods: Computer simulations are used to analyze the maximum stress in the rotary cutter after designing a variety of cutter shapes. Taguchi method is used to identify the robust condition of the cutter. In $L_{18}$ orthogonal array, the control factors such as knife width, twisted angle, number of knives, diameter, knife depth and supported angle are considered and noise factors like assembly tolerance and amount of antifriction are allocated. Results: It is found that the most important factors to reduce maximum stress in the cutter are supported angle and diameter. Using Tacuchi's results, we can reduce 70% cycle time and 9% raw material compared to the traditional method using cutting die. Conclusion: When designing the rotary cutter, the best conditions are the diameter at its maximum allowable value and supported angle in the boundary of machine inner space.