• Journal of Korean Society for Geospatial Information Science
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• v.13 no.4 s.34
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• pp.67-73
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• 2005

The urbanization of Korea has been rapidly progressed since 1960, but satellite imagery have provided the information only after 1975. Recently released CORONA imagery is one of the few source of satellite image which can provide 1960's topographic information of the Korean Peninsular. It can be applied to change detection in various fields such as urban, forest, and environmental planning. In this research mosaic image of past Korean Peninsular using CORONA imagery in the 1960s were generated. A polynomial equation and a modified collinearity equation were applied for geo-referencing and a comparative analysis was conducted. In this research the 2nd polynomial equations were used for geo-referencing of CORONA imagery. After carrying out geo-referencing, mosaic image was generated using Erdas Imagine. It is assumed that this result image is very useful for various fields such as generation of thematic maps, urban planning, and change detection.

• The Journal of the Acoustical Society of Korea
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• v.20 no.8
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• pp.31-37
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• 2001

Following the recent trends of reducing the size of multimedia devices, we tried for the development of a compact-sized speaker to produce low-frequency sounds efficiently. For this work, equivalent-circuit analysis was used to get fundamental resonant frequency and then the structure of speaker components has been changed appropriately. As a result, an 80mm small-sized speaker was developed. The performance test showed that the resonant frequency of our system is 79 Hz while that of numerical analysis was 81Hz. At a distance of 1m from our speaker, the frequency ranges 80 Hz to 15kHz and the average sound pressure was found to be 84±2 dB. The second (at 400 Hz) and the third (at 100 Hz) high-frequency distortions of our system were 0.5% and 1.8% respectively, which is to be compared with the distortions of 0.9% and 6% in conventional speakers.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.7
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• pp.1160-1164
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• 2008

This paper presents an wideband stripline balun. And, the proposed balun is composed of one power divider and two phase converters on stripline substrate. The target characteristics of the proposed balun is the combination loss of below -0.05 dB, an amplitude imbalance of ${\pm}0.5\;dB$ and a phase imbalance of $180{\pm}10$ degrees, with the reflection coefficient(S11) of below -10 dB over frequencies ranging from 500 to 1500 MHz. The fabricated balun occupies the area of $12(W){\times}220(L){\times}2.3(T)\;mm3$. Experimental measurement shows that the fabricated balun has an amplitude imbalance of ${\pm}0.7\;dB$, a phase imbalance of $180{\pm}8$ degrees and an insertion loss of about -2 dB with the reflection coefficient(S11) of below -10 dB over frequencies ranging from 500 to 1,500 MHz.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.448-453
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• 2017

The purpose of this study was to compare the marginal discrepancy of coping crowns according to manufacturing method and materials by using the CAD/CAM system to compare the optimum manufacturing method and materials. The coping crowns were fabricated by using manufacturing methods and materials, and marginal fit was measured using the replica technique. For comparative analysis of manufacturing methods and materials, analysis of variance was performed. One-way ANOVA was performed to compare and analyze different mean values. For the milling method of the alloy, 114.6 was obtained for the MM group, 111.4 for the MS group, 67.2 for the MSC group, and 50.9 for the MSS group, respectively, using the milling/sintering method. In the milling/sintering method of ceramic, 35.6 and 36.3, respectively, were obtained for the SLME group and SLMR group, respectively. However,there was a significant difference according to the material. The milling/sintering method of the ceramic material gave the lowest value, and it was verified by the optimal method. However, marginal discrepancy of coping crowns fabricated using the CAD/CAM system is applicable to the clinic since it corresponds to acceptable numerical values in clinical practice.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.3
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• pp.427-437
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• 2008

In order to increase the coupling efficiency of the power and phase of the active phase array antenna, we have fabricated the active phased-array antenna which is coupled by the transmission line, and investigated the relationship between the length of the coupling transmission line and coupling power and phase. The following three types of driving method - (1) giving the frequency difference between the two active antenna, (2) applying the input signal to the one side of the two antennas, and changing the eigen frequency of the other side antenna, (3) appling the different phase inputs to the active antennas was investigated. The experimental results showed that the interval of the antenna elements has not affected the power and the phase of the antenna.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.396-397
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• 2011

본 논문은 LLC 공진 컨버터를 이용한 고효율 슬림 아답터의 구조를 제안한다. 1차 측의 구리 권선과 2차 측을 그 외부에 PCB를 이용하는 새로운 구조의 슬림한 변압기가 제안되었다. 제안하는 구조는 쉬운 공정성과 넓은 도통 단면적을 가져 고효율의 슬림 컨버터에 적합하다. 또한 2차 측 권선의 간단한 구조를 위해 voltage-doubler 정류기와 출력 필터 사이즈를 줄이기 위해 CLC 필터가 사용되었다. 효과를 확인하기 위해 85W 컨버터를 제작하여 실험하였다.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.118-120
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• 2008

본 논문은 청소차에 쓰이는 IPMSM을 위한 적절한 제어기법을 연구하고, 이를 위한 제어기 보드를 개발하였다. 청소차에 쓰이는 전동기는 주행용, 브러쉬용, 흡입용이 있으며, 용도에 따라 최대 토크 제어 기법과 최적 효율 제어기법을 적용함으로서 목적에 맞는 효과를 기대할 수 있다. 또한 이러한 제어 기법을 적용할 수 있는 제어기 보드를 제작하였다.

• CDE review
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• v.3 no.1
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• pp.45-49
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• 1997

자동차, 조선, 항공 분야 등에서는 3차원 모델러를 이용한 설계작업이 다양하게 이루어지고 있으며 특히 자동차 업계에서는 그 활용도가 대단히 높다. 통상, 완성차 업계에서 작성된 곡면 데이터는 협력업체에서 부품 설계 및 제작에 대단히 중요한 정보가 되기 때문에 이와 같은 곡면정보를 이용하기 위하여 완성차 업체와 동일한 CAD 시스템을 보유하고 있어야 한다. 그러나 완성차 업체에서 사용하고 있는 3차원 모델러(CATIA, Pro/Engineer, 등)는 사용하기가 쉽지 않을 뿐만 아니라 대단히 고가의 장비여서 이를 중소 협력업체에서 구축한다는 것은 현실적으로 매우 어려운 것이 사실이다. 본 고에서는 3차원 모델러 중 자동차 업계에서 가장 많이 쓰이고 있는 CATIA(Dassault사)의 곡면 데이터를 자유로이 응용할 수 있도록 구축한 Jig 설계시스템에 대해 소개하고자 한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.11a
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• pp.217-218
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• 2022

2차 전지는 충방전이 용이하여 적용분야가 급격히 늘어 나고 있으며 대표적으로 납축 배터리를 기반으로 장비등이 제작 사용 되고 있다. 기술의 발전으로 리튬 계열의 2차 전지가 출시 되면서 자동차, 드론등에서 사용되고 있으나 기존 장비와의 전압차등이 존재하여 기존 장비에 적용하기에는 어려움이 있다. 이러한 문제를 모듈 개념을 도입하여 단위 모듈을 기존 납축 전지의 전압에 준하여 구성하고 전류를 최대한 구성하는 방식으로 구성하면 기존 장비 및 신규 장비에 적용이 가능한 방법을 찾을 수 있다.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.3
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• pp.259-264
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• 2014

This paper is research paper on the MPD(Magnet Position Device) for the outdoor MGV(Magnet /Magnet Gyro Guidance Vehicle). Usually, MGV is used in indoor environment because of a measurement height of the magnet position device. CMPD(Commercial magnet position device) has 30 mm measurement height, so this is suitable structure in indoor environment like to a flat surface. Outdoor environment is an uneven and irregular, So Outdoor MGV must has a suspension. But CMPD is unsuitable for outdoor environment because of a collision with a surface caused by suspension. Thus, measurement height of the outdoor MPD is positively necessary more than 100 mm. So, we suggest the outdoor MPD using analog magnet hall sensor, moving average filter and Characteristic(rate of the magnet hall sensor) function of the localization. Result of the experiments, the proposed Magnet Position Device for the outdoor MGV has localization accuracy 4.31 mm, measurement height 150 mm and width 150 mm and is efficient more than CMPD.