• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
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• pp.264-266
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• 2006

This traveling wave tube amplifier maintenance system was developed for performance of microwave Surveillance radar traveling wave tube amplification parts, and field operation. The Maintenance system is traveling wave tube amplification part RF output waveform measurement and HVPS Voltage adjustment and a maintenance function are offer. The system was developed as an embedded system base it consisted of Linux os which applied a top-down design and visual technique. Therefore change and easy extension of a system. This paper discussed characteristic of maintenance equipment function, composition, and an employment program.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1998년도 Proceedings of International Symposium on Remote Sensing
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• pp.180-185
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• 1998

Microwave polarimetric backscattering from a various types of grassland canopies has been analyzed by using the first-order radiative transfer theory in this paper. Leaves in the grassland are modeled by rectangular resistive sheets, which sizes (widths and lengths) and orientations (elevation and azimuth angles) are randomly distributed. Surface roughness and soil moisture of the ground plane under the grass canopy is considered in this computation. The backscattering coefficients of grasslands are computed for different radar parameters (angles, frequencies and Polarizations) as well as different canopy Parameters (size and orientation distributions of leaves, canopy depth, moisture contents of leaves and soil, rms height and correlation length of soil surface). A radar system for 15GHz has been fabricated and used for measurement of the scattering coefficient from a grass canopy. The computation result obtained by the scattering model for the grass canopy is compared with the measurements.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권2호
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• pp.825-836
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• 2016

In this paper, a speed-up technique for the non-local means (NLM) image denoising method based on local binary descriptor (LBD) is proposed. In the NLM, most of the computation time is spent on searching for non-local similar patches in the search window. The local binary descriptor which represents the structure of patch as binary strings is employed to speed up the search process in the NLM. The descriptor allows for a fast and accurate preselection of non-local similar patches by bitwise operations. Using this approach, a tradeoff between time-saving and noise removal can be obtained. Simulations exhibit that despite being principally constructed for speed, the proposed algorithm outperforms in terms of denoising quality as well. Furthermore, a parallel implementation on GPU brings NLM-LBD to real-time image denoising.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.324-327
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• 2008

Microwave remote sensing has great potential, especially in monsoon Asia, since optical observations are often hampered by cloudy conditions. The radar backscattering characteristics of rice crop were investigated with a ground-based automatic scatterometer system. The system was installed inside a shelter in an experimental paddy field at the National Institute of Agricultural Science and Technology (NIAST) before transplanting. The rice cultivar was a kind of Japonica type, called Chuchung. The scatterometer system consists of X-band antennas, HP8720D vector network analyzer, RF cables, and a personal computer that controls frequency, polarization and data storage. This system automatically measures fully-polarimatric backscattering coefficients of rice crop every 10 minutes, accompanied by a digital camera that takes pictures in a fixed position with the same interval. The backscattering coefficients were calculated by applying a radar equation. Plant variables, such as leaf area index (LAI), biomass, plant height and weather conditions were measured periodically throughout the rice growth season. We have performed polarimetric decomposition of paddy data such as single, double and volume scattering to extract the scattering information effectively. We investigated the relationships between backscattering coefficients and the plant variables.

• 한국전자파학회논문지
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• 제22권7호
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• pp.729-736
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• 2011

본 논문은 X-대역에서 바랙터 다이오드가 없는 전압 제어 발진기 구조를 제안하고, 마이크로웨이브 레이더 신호 감지용 수신기에 적용 가능성을 확인하였다. 부성 저항을 발생하는 능동 소자의 콜렉터-베이스 PN-접합으로 바랙터 다이오드를 대체하여, 단일 RF BJT 소자로 전압 제어 발진기를 구현하여 수신기에서 요구하는 튜닝 전압 1.0~7.0 V에서 11.20~11.75 GHz 주파수 가변 특성, 9.0~12.0 dBm 출력 전력 및 선형적인 주파수 튜닝 특성을 만족하였다.

• 한국정보통신학회논문지
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• 제2권3호
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• pp.275-282
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• 1998

본 연구에서는 X밴드 전자식 레이더 반사기에 사용하기 위한 마이크로웨이브 5단 전력증폭기를 평형증폭기 구조를 이용하여 설계하고 제작하였다. 사용한 기판은 FR4이고, 사용한 소자는 FHX35LG, FLK012WF와 FLK022WG이다. 회로의 설계와 최적화는 마이크로웨이브 CAD 프로그램인 CNL/2를 사용하였다. 설계한 주파수 대역에서 측정된 결과는 46dB의 이득과 -14.2dB의 입력반사손실, -16.6dB의 출력반사손실을 나타내며, IM$_3$은 32dBc였다. 측정 결과는 시뮬레이션 결과와 거의 일치하였다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2019년도 추계학술발표대회
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• pp.34-37
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• 2019

유해조수 퇴치 드론의 시스템은 10.525GHz에서 동작하는 Microwave Doppler Radar Sensor를 이용해 경작지에 침입한 조수를 인식한다. 그리고 사용자에게 위험요소에 대한 알림 서비스를 제공한다. 이후 사용자는 드론의 카메라와 카메라 전용 애플리케이션을 이용해 경작지를 실시간으로 보며 드론을 직접 조종하고 Speaker와 Neo Pixel LED Ring를 이용해 유해조수의 시각과 청각을 자극해 도망을 유도하며 퇴치한다.

• 한국초전도ㆍ저온공학회논문지
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• 제23권4호
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• pp.56-60
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• 2021

The microwave Radar used for special purposes in the past is being applied in various areas due to the technological advancement and cost reduction, and is particularly applied to autonomous driving in the automobile field. The FMCW (Frequency Modulated Continuous Wave) Radar can acquire level information of liquid in vessel based on the beat frequency obtained by continuously transmitting and receiving signals by modulating the frequency over time. However, for cryogenic fluids with small impedance differences between liquid medium and gas medium, such as liquid nitrogen and liquid hydrogen, it is difficult to apply a typical Radar-based level meter. In this study, we develop an 80 GHz FMCW Radar for level measurement of cryogenic fluids with small impedance differences between media and analyze its characteristics. Here, because of the low intrinsic impedance difference, most of the transmitted signal passes through the liquid nitrogen interface and is reflected at the bottom of the vessel. To solve this problem, a radar measurement algorithm was designed to detect multiple targets and separate the distance signal to the bottom of the vessel in order to estimate the precise position on the liquid nitrogen interface. Thereafter, performance verification experiments were performed according to the liquid nitrogen level using the developed radar level meter.

• 대한의용생체공학회:의공학회지
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• 제28권4호
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• pp.471-476
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• 2007

Various active microwave imaging techniques have been developed for cancer detection for past several decades. Both the microwave tomography and the UWB radar techniques, constituting functional microwave imaging systems, use the electrical property contrast between normal tissues and malignancies to detect the latter in an early development stage. Even though promising simulation results have been reported, the understanding of the functional microwave imaging diagnostics has been relied heavily on the complicated numerical results. We present a computationally efficient and physically instructive analytical electromagnetic wave channel models developed for functional microwave imaging system in order to detect especially the breast tumors as early as possible. The channel model covers the propagation factors that have been examined in the previous 2-D models, such as the radial spreading, path loss, partial reflection and transmission of the backscattered electromagnetic waves from the tumor cell. The effects of the system noise and the noise from the inhomogeneity of the tissue to the reconstruction algorithm are modeled as well. The characteristics of the reconstructed images of the tumor using the proposed model are compared with those from the confocal microwave imaging.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2006년도 공동학술대회 논문집
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• pp.271-276
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• 2006

이 논문에서는 다편광 Synthetic Aperture Radar (PolSAR) 관측값을 이용하여 남해안 여자만의 조간대 표면 퇴적물에 대한 지구물리학적 특성에 대한 연구를 실시하였다. 원격 탐사를 이용한 조간대 지역의 연구는 종래의 야외 조사를 통한 연구 방법의 한계를 보완할 수 있으며 특히 다편광 SAR 자료는 주 야 및 기상 상태와 관계 없이 지구 표면의 지구물리학적 정보를 정량적으로 획득 할 수 있다. 이 연구를 위하여 사용된 여자만 지역의 다편광 AIRSAR 자료는 2000 년 9 월 30 일 NASA/JPL PACRIM-II 프로젝트를 통해 획득되었다. AIRSAR 자료의 다편광 정보를 이용한 마이크로파의 산란모델을 바탕으로 조간대 지역의 표면퇴적물에서의 마이크로파 산란 특성을 연구하였다.