• 한국광학회지
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• 제2권2호
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• pp.83-88
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• 1991

공간불변(space-invariant) 패턴인식에 대한 연구는 여러 접근방식에서 많은 시도가 이루어지고 있다. 학습 이미지의 가중치 선형조합(weighted linear summation)에 의한 SDF(synthetic discriminant function) 필터를 이용한 패턴인식은 그 중의 한 방식으로서 꾸준히 많은 관심을 받고 있다. 본 논문에서는 off-axis 평면기준파의 각분할(angular multiplexing) 방식과 pseude-inverse 알고리듬에 의한 pSDF 필터를 결합하여 상관기를 구성하고 상관면에서의 상관반응을 관측하여, off-axis pSDF 공간정합필터가 유형분류에 유용함을 입증하고, 광상관기로의 적용가능성을 보여주고자 한다.

• 한국광학회:학술대회논문집
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• 한국광학회 1989년도 제4회 파동 및 레이저 학술발표회 4th Conference on Waves and lasers 논문집 - 한국광학회
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• pp.143-146
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• 1989

Narrowband bandpass waveguide filters using inducive post obstacles are designed and constructed to have an equal-ripple bandwidth of 50MHz at a center frequency of 9GHz. Both the triple-post and the single-post configurations are realized and compared. The measured results for both filters show good agreement with the theoretical calculations. When the two filters are compared, the performance of the triple-post filter is better than that of the single-post filter.

• 한국광학회:학술대회논문집
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• 한국광학회 2004년도 제15회 정기총회 및 동계학술발표회
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• pp.292-293
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• 2004

• 한국통신학회논문지
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• 제21권1호
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• pp.269-280
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• 1996

광병렬 가산을 위한 광산광 기호치환법을 제안하였다. 제안된 광상광 기호치환 방법에서는 기호치환 규칙 수의 최소화가 용이한 잉여 이진수를 사용하였으며, 광상관 필터로는 SDF 필터에 비해 부엽이 아주 작고 상관치 제어가 우수한 MACE필터를 선택하였다. 또한 분리 인식능력을 증가시키기 위해 입력을 적절히 부호화하였으며, 기호치환 규칙의 수를 최소화하기 위하여 동일한 가산결과를 갖는 입력패턴들을 동일군으로 하여 5개의 군으로 나누었다. 그리고 제안한 방법이 광병렬 가산기의 구현에 적합함을 컴퓨터 시뮬레이션을 통하여 확인하였다.

• Asian Journal of Atmospheric Environment
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• 제6권4호
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• pp.268-274
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• 2012

To perform quick measurements of black carbon (BC) particles deposited on foliar surfaces of forest tree species, we investigated an optical method for measuring the amount of BC extracted from foliar surfaces and collected on quartz fiber filters. The seedlings of Fagus crenata, Castanopsis sieboldii, Larix kaempferi and Cryptomeria japonica were exposed to submicron BC particles for one growing season (1 June to 7 December 2009). At the end of the growing season, the leaves or needles of the seedlings were harvested and washed with deionized water followed by washing with chloroform to extract the BC particles deposited on the foliar surfaces. The extracted BC particles were collected on a quartz fiber filter. The absorption spectrum of the filters was measured by spectrophotometer with an integrating sphere. To obtain the relationship between the absorbance of the filter and the amount of BC particles on the filter, the amount of BC particles on the filter was determined as that of elemental carbon (EC) measured by a thermal optical method. At wavelengths below 450 nm, the absorption spectrum of the filter showed absorption by biological substances, such as epicuticular wax, resulting in the low coefficient of determination ($R^2$) in the relationship between the amount of EC on the filter ($M_{EC}$, ${\mu}g\;C\;cm^{-2}$ filter area) and the absorbance of the filter. The intercept of the regression line between $M_{EC}$ and the absorbance of the filter at 580 nm ($A_{580}$) was closest to 0. There was a significant linear relationship between the $A_{580}$ and $M_{EC}$ ($R^2$=0.917, p<0.001), suggesting that the amount of BC particles collected on the filter can be predicted from the absorbance. This optical method might serve as a simple, fast and cost-effective technique for measuring the amount of BC on foliar surfaces.

• 한국광학회:학술대회논문집
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• 한국광학회 2000년도 하계학술발표회
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• pp.18-19
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• 2000

In this paper, packet error rates of an all-optical packet switching node, which uses a fiber-optic delay-line matched filter as the optical packet header processor, has been calculated for the various optical pulse shapes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권2호
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• pp.643-661
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• 2018

This paper proposes a novel algorithm for lane detection based on inverse perspective transformation and Kalman filter. A simple inverse perspective transformation method is presented to remove perspective effects and generate a top-view image. This method does not need to obtain the internal and external parameters of the camera. The Gaussian kernel function is used to convolute the image to highlight the lane lines, and then an iterative threshold method is used to segment the image. A searching method is applied in the top-view image obtained from the inverse perspective transformation to determine the lane points and their positions. Combining with feature voting mechanism, the detected lane points are fitted as a straight line. Kalman filter is then applied to optimize and track the lane lines and improve the detection robustness. The experimental results show that the proposed method works well in various road conditions and meet the real-time requirements.

• 한국광학회지
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• 제19권3호
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• pp.242-245
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• 2008

본 논문에서는 $1{\times}4$ 스위치와 서로 다른 FSR(free spectral ranges)을 갖는 마이크로링 공진기 배열을 결합하여 구현된 광공진기 라우터를 기반으로 하는 집적광학 방식의 4채널 선택 마이크로웨이브(microwave: MW) 필터를 제안하고 구현하였다. 중심 주파수는 링 공진기의 반지름에 따른 FSR에 의해 결정되며, 이를 통해 얻어지는 10 GHz, 16 GHz, 18 GHz, 20 GHz로 구성된 4개의 채널은 광스위치에 제어 전압을 인가하여 개별적으로 선택할 수 있었다.

• 마이크로전자및패키징학회지
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• 제29권1호
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• pp.67-70
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• 2022

본 연구는 최근 유행하고 있는 코로나 바이러스(SARS-CoV-2) UV 살균을 위한 1차원 광자 준결정 구조 개념의 광학 필터를 설계하고 시뮬레이션 하였다. 시뮬레이터는 수치해석 프로그램으로 사용되는 MATLAB 프로그램과 직접 코딩한 연산수식을 사용하였다. 비주기(복합구조) 다중층 구조 모델을 설계한 후, 특성 계산을 위하여 다중층 구조 모델의 물성치를 천이 행렬법(TMM, Transfer Matrix Method)으로 설정하였다. 설계된 복합 다중층 구조의 MATLAB을 활용한 전산모사법을 통하여 얻은 행렬값으로부터 반사도와 투과도를 계산하였다. 이 연구의 결과로 인체에 무해하면서 코로나 바이러스 UV 살균이 가능한 253.7 nm 파장만을 투과하는 광학 필터의 제작 및 응용 가능성을 증명하였다.

• Current Optics and Photonics
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• 제7권4호
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• pp.345-353
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• 2023

We propose a turbulence-tolerant Manchester on-off keying (M-OOK) transmission for free-space optical (FSO) communication. At the transmitter end, a M-OOK signal featuring a spectrum with low-frequency components absent is modulated and transmitted into a turbulent channel. At the receiver end, a low-pass filter (LPF) -based adaptive-threshold decision (ATD) with LPF-extracted channel-state information (CSI) and a high-pass filter (HPF)-based fixed-threshold decision (FTD) are employed to compensate for the effects of turbulence, owing to the low-frequency spectral characteristics of the turbulent channel. The performance of LPF-based ATD and HPF-based FTD are evaluated for various cutoff frequencies for the LPF and HPF. Besides, the proposed M-OOK transmission is compared to conventional non-return-to-zero OOK (NRZ-OOK) for different data rates. The proposed technique is verified in simulation. The simulation results show that the proposed M-OOK detection with optimized cutoff frequencies of LPF and HPF has better bit-error-rate (BER) performance compared to NRZ-OOK, and it is close to the theoretical ATD with the knowledge of precise CSI under various degrees of turbulence effects.