• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.5
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• pp.86-94
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• 2008

In this paper proposed the solar tracking system to use a fuzzy based on PC in of order to increase an output of the PV(Photovoltaic) array. The solar tracking system operated two DC motors driving by signal of photo sensor. The control of dual axes is not an easy task due to nonlinear dynamics and unavailability of the parameters. Recently, artificial intelligent control of the fuzzy control, neural-network and genetic algorithm etc. have been studies. The fuzzy control made a nonlinear dynamics to well perform and had a robust and highly efficient characteristic about a parameter variable as well as a nonlinear characteristic. Hence the fuzzy control was used to perform the tracking system after comparing with error values of setting-up, nonlinear altitude and azimuth. In this paper designed a fuzzy controller for improving output of PV array and evaluated comparison with efficient of conventional PI controller. The data which were obtained by experiment were able to show a validity of the proposed controller.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.1
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• pp.53-64
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• 2004

This paper proposes a monopulse beamforming network to estimate a target angle in interference conditions. The proposed system estimates the target direction of arrival (DOA) with two separate beamformings for azimuth and elevation with a planar may. The elevation is extracted from adaptive beamforming in the azimuth direction and the azimuth from adaptive beamforming in the elevation direction. Unlike conventional monopulse beamforming techniques using complex correction formulas or a cascaded architecture of an adaptive array and a mainlobe canceller, the proposed system is very efficient from the computational complexity. The advantage is from fact that the monopulse ratio of the proposed system does not depend on the adapted weights. Moreover, the proposed system can estimate the DOA of the target even for multiple mainlobe interferences since it does not need my kinds of mainlobe maintenance technique.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.10
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• pp.1089-1097
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• 2002

In this paper, the novel shipboard Active Phased Array Antenna(APAA) system for maritime mobile satellite communications is introduced. The antenna uses novel technologies like wide range hybrid tracking, single antenna elements with both of Rx and Tx, asymmetrical array structure, interference isolation between Rx and Tx, and error correction method from frequency scan effect. The antenna has single aperture for both of Rx and Tx with 32 $\times$ 4 two-dimensional array. The antenna has two beams. Its frequencies are 7.25 ~ 7.75 GHz for Rx and 7.9 ~ 8.4 GHz for Tx. The antenna gains are 35.4 dBi for Rx and 35.7 dBi for Tx, those are 54 % of efficiency. The electrically steering ranges are $\pm$35$^{\circ}$ of elevation direction and $\pm$4$^{\circ}$ of azimuth direction. The mechanical control ranges at hybrid tracking capability are continuous 360$^{\circ}$ of azimuth direction and $\pm$10$^{\circ}$ of elevation direction. The antenna has 2.2$^{\circ}$ of 3 dB beamwidth, -14 dB of sidelobe level, and 21 dB of cross-pol suppression. The antenna performance was measured by near field measurement set. Its system performance was tested on the ship motion simulator and with the satellite transponder simulator. The test result showed that its tracking error was within -3 dB from its peak gain under motion condition. The antenna system was tested by real modulated Direct Broadcasting Satellite(DBS) signals to check its communication processing function.

• Journal of Aerospace System Engineering
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• v.16 no.4
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• pp.60-67
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• 2022

An Electro-Optical Tracking System (EOTS) is an electric optical system with EO/IR cameras, laser sensors, and an IMU. The EOTS calculates coordinates of targets, using attitude and acceleration measured by the IMU. In particular for an armed aircraft, the performance of the weapon system depends on how quickly and accurately it acquires the target coordinates. The IMU should be operated after alignment is complete, to meet the coordinate accuracy required by the weapon system so the initial stabilization time of the IMU should be reduced, by quickly measuring the attitude and acceleration. Alignment is the process of determining the initial attitude by resolving the attitude error of the IMU, and the IMU of mission equipment such as an airborne EOTS, uses velocity matching based on the velocity from GPS/INS for aircraft navigation. In this paper, a method is presented to improve the transfer alignment performance of the airborne EOTS, by maneuvering aircraft and the mission equipment. First, the performance factor of the alignment was identified, as a heading error through the velocity matching model and simulation results. Then acceleration maneuvers and attitude changes were necessary, to correct the error. As a result of flight tests applied to an EOTS on a OOO aircraft system, the transfer alignment performance was improved as the duration time was decreased, by more than five times when the aircraft accelerated by more than 0.2g and the EOTS was moving until 6.7deg/s.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.124-124
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• 2017

본 연구에서 원추형 집광기와 CPV셀을 기반으로 한 태양광-열(CPV/T) 복합시스템의 설계 및 제작과정을 다룬다. 원추형 집광기의 경우, 이론적 해석을 통하여 최고의 집열효율을 갖는 원추각 45도의 집광기 4개를 결합하여 사용하였다. 원추형 복합시스템은 태양에너지를 집열하여 열에너지를 생산하는 집광기와 작동유체의 순환을 위해 이중 구조로 제작된 흡수기, 집광된 태양으로부터 전기에너지를 생산하는 CPV셀 등으로 구성되어 있다. 효율적인 태양복사열 집광을 위해 태양 위치에 따라 고도각과 방위각을 추적할 수 있는 2축 태양추적장치를 설비하였다. CPV셀은 원추형 집광기의 중심부에 위치한 이중 흡수관의 고집광부인 상단부에 위치하였으며, CPV셀의 결함을 방지하고, 부가적 태양광 집광을 위해 2차 보조 집광기를 부착하였다. 본 논문에서 소개하는 원추형 CPV/T 복합 시스템은 기존 원추형 시스템에 CPV 셀을 부착하여 전기와 열을 동시에 생산 할 수 있으며, 생산된 전기에너지와 열에너지를 이용하여 온실재배의 난방 문제, 운영비용 절약 등 다양하게 농업 분야에 적용가능하다. 특히, 원추형 복합시스템은 설계 및 제작에 있어 쉽고 간결하며, 제작 단가가 낮다는 점에서 보급에 이점이 있을 것으로 사료된다.

• Journal of the Korean Solar Energy Society
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• v.32 no.3
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• pp.129-137
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• 2012

This thesis introduced an azimuth tracking prismatic daylighting system. The system improved several issues of the previous passive prismatic daylighting system: low efficiency at sunrise and sunset, glare effect and polarized. The system was developed to track the movement of sun with azimuth tracking device, and it has its own power from the attached solar cells. We compared the with previous passive one in terms with system efficiency and daylighting factors(DF).

• Korean Journal of Remote Sensing
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• v.34 no.2_2
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• pp.313-326
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• 2018

This paper introduces core techniques on ship detection and tracking based on a compact HF radar platform which is necessary to establish a wide-area surveillance network. Currently, most HF radar sites are primarily optimized for observing sea surface radial velocities and bearings. Therefore, many ship detection systems are vulnerable to error sources such as environmental noise and clutter when they are applied to these practical surface current observation purpose systems. In addition, due to Korea's geographical features, only compact HF radars which generates non-uniform antenna response and has no information on target information are applicable. The ship detection and tracking techniques discussed in this paper considers these practical conditions and were evaluated by real data collected from the Yellow Sea, Korea. The proposed method is composed of two parts. In the first part, ship detection, a constant false alarm rate based detector was applied and was enhanced by a PCA subspace decomposition method which reduces noise. To merge multiple detections originated from a single target due to the Doppler effect during long CPIs, a clustering method was applied. Finally, data association framework eliminates false detections by considering ship maneuvering over time. According to evaluation results, it is claimed that the proposed method produces satisfactory results within certain ranges.

• The Korean Journal of Air & Space Law and Policy
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• v.32 no.1
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• pp.201-224
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• 2017

The main subject of this article focused on the legal status of the military aircraft in the high seas. For this the legal status of the military aircraft, the freedom of overflight, the right of hot pursuit, the right of visit and Air Defense Identification Zone (ADIZ) were dealt. The 1944 Chicago Convention neither explicitly nor implicitly negated the customary norms affecting the legal status of military aircraft as initially codified within the 1919 Paris Convention. So the status of military aircraft was not redefined with the Chicago Convention and remains, as stated in the 1919 Paris Convention, as a norm of customary international law. The analyses on the legal status of the military aircraft in the high seas are found as follows; According to the Article 95 of the 1982 United Nations Convention on the Law of the Sea (UNCLOS) warships on the high seas have complete immunity from the jurisdiction of any State other than the flag State. We can suppose that the military aircraft in the high seas have also complete immunity from the jurisdiction of any State other than the flag State. According to the Article 111 (5) of the UNCLOS the right of hot pursuit may be exercised only by warships or military aircraft, or other ships or aircraft clearly marked and identifiable as being on government service and authorized to that effect. We can conclude that the right of hot pursuit may be exercised by military aircraft. According to the Article 110 of the UNCLOS a warship which encounters on the high seas a foreign ship, is not justified in boarding it unless there is reasonable ground for suspecting that: (a) the ship is engaged in piracy, (b) the ship is engaged in the slave trade, (c) the ship is engaged in an unauthorized broadcasting and the flag State of the warship has jurisdiction under article 109, (d) the ship is without nationality, or (e) though flying a foreign flag or refusing to show its flag, the ship is, in reality, of the same nationality as the warship. These provisions apply mutatis mutandis to military aircraft. As for Air Defence Identification Zone (ADIZ) it is established and declared unilaterally by the air force of a state for the national security. However, there are no articles dealing with it in the 1944 Chicago Convention and there are no international standards to recognize or prohibit the establishment of ADIZs. ADIZ is not interpreted as the expansion of territorial airspace.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.5
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• pp.532-541
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• 2014

The ship-borne mobile down range telemetry antenna system having 4.6 m reflector antenna and 3-axis mounting structure at S-band requires the precise pointing accuracy at sea for the launch mission. Using the LEO satellites tracking, a method to determine and verify the antenna pointing and tracking performance, and to find the pointing bias which dominantly contributes to the pointing inaccuracy, is presented. Based upon the tests conducted on the Jeju sea and Pacific sea, the pointing bias is determined and its origin is also identified as the drift of the heading angle of the gyrocompass. The applied systematic correction taking into account the pointing bias, and the achieved improvement of the pointing accuracy are shown. Thanks to the correction, it is presented that this antenna tracked the launcher(KSLV-I) stably within the required pointing accuracy in the following KSLV-I third launch.

• Journal of Advanced Navigation Technology
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• v.8 no.1
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• pp.49-57
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• 2004

In This paper the embedded linux based embedded control system was used and the tracking antenna system was studied for data link and communication between moving vehicles. A microprocessor based embedded controller is equipped with SA-1110 board and this embedded controller can control the azimuth and the elevation angle of the antenna. The relative position and attitude for pointing are calculated by using the GPS position signals from the moving vehicle. To verify the performance of the designed embedded antenna system, the orbit information of the Arirang satellite(from KARI) is used.