• Proceedings of the Korean Information Science Society Conference
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• 2000.10c
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• pp.62-64
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• 2000

레이다 빔 스케쥴러는 레이타의 전체적인 운용과 제어를 담당하는 레이다 통제기의 핵심기능으로서 레이다의 운용시간 및 송신 전력 등 한정된 가용 자원을 효율적으로 관리하기 위한 최적화 기법이 매우 중요하다. 본 논문은 충남대에서 개발한 실시간 운용체제인 iRTOS를 기반으로 하여 방위각 방향은 기계적 회전을 하고 고각 방향은 위상을 가변하여 다수의 위협 표적을 실시간으로 탐지하고 추적하는 회전형 3차원 위상배열 레이다에 적용 가능한 레이다 빔 스케쥴러의 구현 알고리즘에 관한 내용이다. 제안된 레이다 빔 스케쥴러는 우선 순위를 갖는 핵심적인 스케쥴링 태스크와 이를 보조하기 위한 다수의 기능 태스크를 정의하고 생성하였으며 태스크간 데이터 교환을 위하여 인터럽트 처리, 시간 관리, 세마포어 및 메시지 큐 등을 적용하였다. 레이다 빔 스케쥴러의 성능을 검증하기 위하여 다수의 모의 표적을 발생시켜 빔 스케쥴러의 상태와 성능을 확인하였으며, 자체 개발한 실시간 운용체제인 iRTOS를 이용하여 3차원 레이다 빔 스케쥴러를 구현할 수 있음을 확인하였다.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.8
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• pp.7-18
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• 1999

We have designed and tuilt the quasioptical system for the dual channel receiver which is used for the simultaneous observation of the cosmic radio with 100GHz band and 150GHz band. The quasioptical system has been widely used to guide the beam for the millimeter and submillimeter waves. A Gaussian distribution of field and power transverse to their axis of propagation allow the simple and elegant theory of Gaussian quasioptics. Using the theory of Gaussian beam, we introduced the analysis of image beam which is applied for a wide range of frequency. In order to guide two beams from the Cassegrain antenna simultaneously, the quasioptical system and its components for the dual channel receiver were designed by using the image beam method. We have checked the characteristics of the quasioptical components and the system by using the heam measurement system, which is made by us. The quasioptical system has been installed in the dual channel receiver on the Cassegrain antenna. The performance of this system has been finally confimed through the successful simultaneous observation with two bands of the cosmic radio.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.2
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• pp.111-118
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• 2016

This paper presents an X-band (9.375 GHz) $1{\times}2$ array microstrip antenna which is capable of active beam compensation for installation of an unmanned aerial vehicle (UAV). First of all, a basic $1{\times}2$ array microstrip antenna incorporated with wilkinson power divider was designed and performance of the array antenna was verified. Next, to verify beam steering performance of the designed array microstrip antenna, we fabricated a phase shifter, and the wilkinson power divider as module structure and measured characteristics of beam steering according to phase shifting. The main lobe is 0.6 dBi at $0^{\circ}$, and the side lobe decreased 18.8 dB. The reliable radiation pattern was achieved. Finally, an active beam steering microstrip array antenna attached with the phase shifter and the power divider on the back side of the antenna was designed and fabricated to install wing of UAV for compactness. The maximum gain is 0.1 dBi. Therefore, we obtained a basic antenna technology for compensating beam error according to wing deformation of an UAV installed array antennas.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.10
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• pp.876-884
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• 2015

In this paper, a switched beamforming antenna system at 28 GHz frequency band is described for $5^{th}$ generation wireless communication. The butler matrix is used as a beamforming system and it produces linear spaced phase difference at four output ports. Array antenna is designed that can be steered in desired 4 different directions 28 GHz frequency band. Operation of designed butler matrix that composed of couplers and feedline is explained. The antenna system is designed in RO3003 substrate that has a height of 5 mil and dielectric constant of 3. The size of butler matrix is $20.3{\times}13.0mm^2$ and size of array antenna is $21.2{\times}19.9mm^2$. This system can be steered from $-34^{\circ}$ to $33^{\circ}$ and minimum sidelobe level is 12.9 dB.

• The Journal of the Acoustical Society of Korea
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• v.23 no.8
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• pp.570-575
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• 2004

In the underwater acoustic systems. we can receive signals and retrieve information about a target by using a beamforming method. The most important thing in the beamforming is finding the way to optimize the mainlobe beamwidth and the sidelobe level to the desired value. One of the prominent results of beamforming method. which has been studied. is Philip's weighting function method(1) . Philip's method adaptively adjusts its weights of array to meet the desired mainlobe beamwidth and sidelobe level. It is very similar to the design method in adaptive filter. However. this method cannot easily bring us to the desired sidelobe level due to complementary relation between mainlobe beamwidth and sidelobe level. In this paper, we propose a new algorithm using partial constrained adaptation. This method makes us circumvent the above problem and meet the specification of design easily. The proposed algorithm presents a Pattern synthesis that designer can easily control the mainlobe beamwidth and the sidelobe level to the desired value while calculation time to converge is decreasing.

• Journal of the Korean Society for Railway
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• v.14 no.6
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• pp.477-483
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• 2011

In this paper, noise source localization of the Korean high speed train was conducted by using delay and sum beam-forming method of a microphone array. At first, the microphone array having irregular configuration was designed and the resolution of which was analyzed from parameters such as 3-dB bandwidth and maximum side-lobe level. After the demonstration, the microphone array was applied on the high speed train and noise localization of the high speed train driving at 300 km/h was performed successfully.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.288-288
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• 2010

현대사회의 급속한 고령화로 암 환자의 수는 2002년 기준 약 10만 명에서 매년 7~10 %씩 증가되어 2012년에는 20만 명이 될 것으로 추정되어지고 있다. 수술, 방사선 치료, 약물요법 등이 주요 치료방법이며, 암 환자의 30-50 %가 전리 방사선치료를 받고 있다. 방사선치료는 19세기 말에 발견된 미지의 X-선이 희망의 방사선으로 변화하여 암의 진단 및 치료에 활용되고 있으며, 인간 삶의 질 향상에 핵심적인 역할을 담당하고 있다. 기존의 X-선이나 감마선의 단점을 극복 할 수 있는 입자 빔을 1970년대 미국의 캘리포니아 대학 Berkely National Laboratory에서 처음으로 암 치료에 적용하였다. 현재는 일본과 독일에서 활발하게 활용되고 있으며 국내에서도 입자 치료시설을 구축 또는 개발계획 중에 있다. 방사선치료의 완치율을 높이기 위해서는 정확한 선량을 암세포에 전달해야 한다. 환자에 전달되는 입자빔을 실시간으로 측정하는 기술이 연구되어지고 있다. 지금까지는 빔의 특성을 측정하기 위해 간섭적인 방법을 사용하였으나, 투과형 검출기를 개발하여 실시간으로 치료와 빔 특성을 동시에 수행하는 기술개발연구가 보고되고 있다. 본 연구에서는 Multileaf Faraday Cup (MLPC) 검출기 설계구조와 데이터 측정방법에 관한 연구를 수행하고자 한다. 빔의 전송 방향으로 3개층의 $4{\times}4$ 배열의 구조로 48 channel의 전류값을 측정하여 입자빔의 분포를 실시간으로 관측하고, 측정된 전류는 ADC를 거쳐 치료계획에 의해 선택된 영역의 SOBP를 유지하도록 range modulation propeller를 조절하는 feed-back system을 갖춘 방사선치료빔 실시간 측정장치 개발에 관한 결과를 보고하고자 한다.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.6
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• pp.111-117
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• 2018

In this study, an MEMS thrust measurement system was designed and a study on the performance prediction of system was performed to evaluate the performance of micro thruster. Thrust measurement system consists of beam, membrane, and piezoresistive sensor. An FEM analysis was carried out to verify the stability of the system, confirm the stress variation at the beam, and position the piezoresistive sensor. The stability of the designed system was verified by comparing the yield strength of the material with the maximum stress. The piezoresistive sensor was designed to be 20% of the length of the beam to obtain a high gauge factor. The size of the membrane and the beam of the reference model were designed to be $15mm{\times}15mm$, and $500{\mu}m{\times}500{\mu}m$, respectively.

• Journal of the Korean Geotechnical Society
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• v.26 no.6
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• pp.39-44
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• 2010

In case of the design method, which is used in the inside and outside of the country, on corrugated multi plate structures, section modulus would be determined by assuming 2-dementioanl equivalent section of those structures. However, it is impossible to consider 3-dimentional effects when 2-dimentional design method is applied since structures are reinforced with a pattern of the 1200, 1600 mm reinforcements except the 800 mm reinforcement. Thus, in this study, technical specification standard is analyzed for the existing corrugated multi plate design methods, and section strengths, moments, and so on of equivalent and practical sections are compared and estimated using 3-dimentional FEM (finite element method) for semicircles and architectural features widely used. Based on the results of that analysis, analytical basis for 3-dimentional design of the CBS-RIB is suggested.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.94.1-94.1
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• 2015

4세대 방사광 가속기는 선형가속기와 언듈레이터를 활용하여 파장이 0.1 nm인 X선을 빔라인 사용자들에게 제공하는 것을 목표로 하여 2011년부터 건설되고 있다. 이 장치에서 진공시스템은 전자빔 발생장치인 RF Gun을 포함하는 입사장치(Injector)와 빔을 가속시키는 선형가속기(Linac) 그리고 결맞음 방사광을 발생시키는 언듈레이터로 나누어진다. 본 논문에서는 최종 수정 설계 후 제작 및 설치 중인 진공시스템의 건설 현황에 대하여 집중적으로 보고하고자 한다.