• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.1
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• pp.68-76
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• 2015

This paper proposes the antenna selection scheme and power control algorithms of multiple nodes beamforming when the vehicles equipped with circular array antennas is moving and construct mobile mesh networks. The proposed antenna selection scheme chooses beamforming antenna elements considering antenna radiation gain and allows duplicated antenna selection for multiple adjacent nodes. The proposed power control algorithms maximize SIR for the duplicated antenna selection. The simulation demonstrates that the proposed antenna selection and power control achieve 2.5dB higher SIR gain than that of conventional methods when two nodes are apart from $15^{\circ}$.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.45-47
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• 2001

본 논문은 WCDMA 시스템의 역방향 링크에서의 빔포밍 적용에 관하여 기술하였다. 제안된 빔포밍 구조는 제어채널의 파일럿 심볼을 이용한 빔포밍 계수계산과 데이터 채널에 적용하는 분리구조를 가지고 있다. 적응 빔포밍의 대표적 방식인 LMS 알고리즘과steering 알고리즘을 적용하여 성능 분석과 시뮬레이션을 수행하였으며, 다양한 환경 변수에 따른 시뮬레이션 결과는 빔포밍 알고리즘의 구현과 설계에 있어 중요한 지침을 주리라 기대된다.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2502-2504
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• 2001

본 논문은 WCDMA 시스템의 역방향 링크에서의 빔포밍 적용에 관하여 기술하였다. 제안된 빔포밍 구조는 제어채널의 파일럿 심볼을 이용한 빔포밍 계수 계산과 데이터 채널에 적용하는 분리구조를 가지고 있다. 적응 빔포밍의 대표적 방식인 LMS 알고리즘과 steering 알고리즘을 적용하여 성능 분석과 시뮬레이션을 수행하였으며, 다양한 환경 변수에 따른 시뮬레이션 결과는 빔포밍 알고리즘의 구현과 설계에 있어 중요한 지침을 주리라 기대된다.

• Proceedings of the Optical Society of Korea Conference
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• 2000.08a
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• pp.72-73
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• 2000

단원자를 이용한 Cavity-QED 실험을 통해서 광자 수상태 및 sub-poissonian 광원 구현 및 비고 전적인 광 특성을 가지는 광원등을 구현 할 수 있다. 이를 위해서는 오랫동안 공진기 안에 포획하거나, 빔의 형태로 단원자들이 일정시간 동안 공진기를 지나게 해야 한다. 본 연구는 안정한 원자빔 속도제어 실험에 관한 것으로 자체 제작한 원자빔 오븐의 특성과 원자빔 속도 선택기의 제작, 속도 선택 결과에 대하여 논하고자 한다. (중략)

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.6
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• pp.449-456
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• 2018

Herein, several multibeam forming methods that can be applied to microwave wireless power transmission are presented. Because the conventional multibeam forming methods do not consider an active element pattern(AEP), an intended beam shape will contain a steering angle error when applied to an actual system. To solve this problem, a method of considering the average of the AEP and a method of considering all the AEPs by the modified Fourier series method have been proposed. We confirmed that the proposed method reduces the error with the intended beam shape in the multibeam formation. In addition, for the side lobe level(SLL) and null control, a method of multibeam forming by applying the superposition principle to the Dolph-Tschebyscheff method is proposed. We also confirmed that SLL control can be simultaneously achieved with the multibeam formation.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.303-306
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• 2002

본 논문에서는 IMT-2000 WCDMA 시스템의 기지국의 수신신호에 대한 WCDMA 역방향링크 디지털 빔포밍 적용구조를 제시하고, 이의 성능을 측정하기 위한 빔포밍 시뮬레이터를 구현하였다. 실제 WCDMA 시스템에 근거해 수신 신호를 모델링하고, 기본 신호 모델을 대상으로 빔포밍과 전력제어등의 알고리즘을 적용하였다. 또한 셀네의 각 사용자들의 이동을 정의한 사용자 이동 프로파일을 구성하여 적용함으로써 실제 이동통신이 이루어지는 환경과 유사한 시뮬레이션 환경을 설정하게 되었고, 이를 통하여 빔포밍을 적용한 시스템에 대한 성능 분석의 신뢰도를 향상시켰다

• Journal of Satellite, Information and Communications
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• v.7 no.2
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• pp.25-29
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• 2012

In this paper, we implemented LED beam forming communication system controlled by stepping motor. ATMega1284 was used as a MCU of main control board which has two main external IO, one is RS232 for connection with PC, the other is PORT for connection with motor driving board. Stepping motor rotated 360 degree when provided 160 clock and its rotation radius was increased by Archimedian Spiral. So LED can provide its light anywhere in the space and its beam forming was controlled by PC connected with RS232 of main control board. The action of beam forming was verified via actual HW/SW implementation.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.2
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• pp.41-51
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• 2004

In this paper, the beam steering dipole phased array antenna systems for IMT-2000 base station have been designed. The designed beam steering dipole phased array antenna systems are constituted by the antenna part and the beam steering control system part. The antenna part is designed by the proposed flat dipole for the broadband characteristics, and the 8${\times}$8 dipole array antenna is constructed by the proposed flat dipole for the directional radiation pattern. Besides the vertical power divider is designed for the vertical power distribution. The beam steering control system part is designed the horizontal power divider for the horizontal power distribution, the 4-bit phase shifters and the driving circuit of phase shifters for the horizontal beam tilting. In order to evaluate a performance of the designed antenna systems, they were fabricated and the radiation characteristics were measured. From the measured results, we found that the horizontal beams were tilted by the each control signals, and the measured radiation characteristics showed good agreement with the design goals.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.7B
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• pp.891-894
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• 2001

본 논문에서는 능동 배열 안테나에서 RF 대신 중간주파수를 이용하여 빔 추적을 하는 방법이 연구되었다. 안테나의 각 배열은 전압제어 발진기, 위상추적기, 혼합기와 결합되어 있으며 혼합기는 안테나 상에서 직접 RF 신호를 직접 중간주파수 신호로 변환시킨다. 전압제어 발진기 입력은 위상추적기에 의하여 조절되며 배열 안테나의 주사범위는 위상추적기와 전압제어발진기에 의하여 결정되었다.

• Korean Journal of Optics and Photonics
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• v.34 no.1
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• pp.1-12
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• 2023

In this study, we propose a hybrid phase-control algorithm for multi-channel coherent beam combining (CBC) system by combining the covariant matrix adaption evolution strategy (CMA-ES) and stochastic parallel gradient descent (SPGD) algorithms and analyze its operational performance. The proposed hybrid CMA-ES/SPGD algorithm is a sequential process which initially runs the CMA-ES algorithm until the combined final output intensity reaches a preset interim value, and then switches to running the SPGD algorithm to the end of the whole process. For ideal 7-channel and 19-channel all-fiber-based CBC systems, we have found that the mean convergence time can be reduced by about 10% in comparison with the case when the SPGD algorithm is implemented alone. Furthermore, we analyzed a more realistic situation in which some additional phase noise was introduced in the same CBC system. As a result, it is shown that the proposed algorithm reduces the mean convergence time by about 17% for a 7-channel CBC system and 16-27% for a 19-channel system compared to the existing SPGD alone algorithm. We expect that for implementing a CBC system in a real outdoor environment where phase noise cannot be ignored, the hybrid CMA-ES/SPGD algorithm proposed in this study will be exploited very usefully.