• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.489-492
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• 2000

본 논문에서는 영상 항법 변수 추출 알고리듬의 실시간 구현에 관해 연구하였다. 영상 항법 변수 추출 알고리듬은 이전 위치를 기준으로 현재 위치를 추정해내는 상대위치 추정 알고리듬과 상대위치 추정에 의해 누적되는 오차를 보정하기 위한 절대위치 보정 알고리듬으로 구성된다. 절대위치 보정 알고리듬은 고해상도 영상과 IRS (Indian Remote Sensing) 위성영상을 기준영상으로 이용하는 방법 및 DEM (Digital Elevation Model) 을 이용하는 방법으로 구성된다. 하이브리드 영상 항법 변수 추출 알고리듬을 실시간으로 구현하기 위해 MVP (Multimedia Video Processor)로 명명된 TMS320C80 DSP (Digital Signal Processor) 칩을 사용하였다. 구현된 시스템은 MVP의 부동 소수점 프로세서인 MP (Master Processor) 를 고정 소수점 프로세서인 PP (Parallel Processor) 를 제어하거나 삼각함수 계산과 같은 부동 소수점 함수를 계산하는데 사용하였고, 대부분의 연산은 PP를 사용하여 수행하였다. 처리시간이 많이 필요한 모듈에 대해서는 고속 알고리듬을 개발하였고, 4개의 PP를 효율적으로 사용하기 위한 영상분할 방법에 대해 제안하였다. 비행체에서 캡코더를 이용해 촬영한 연속 항공 영상과 비행체의 자세정보를 입력으로 실시간 시뮬레이션 하였다. 실험결과는 하이브리드 항법 변수 추출 알고리듬의 실시간 구현이 효과적으로 구현되었음을 나타내고 있다.

• The Korean Journal of Pesticide Science
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• v.11 no.2
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• pp.67-71
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• 2007

Nobel series of 5-benzyloxymethyl-3-(thiophen-5-yl)-1,2-isoxazoline derivatives were designed and synthesized. The herbicidal activities of these compounds to main dominant weeds to these compounds were evaluated in pot tests that simulated rice paddy conditions. Most of the compounds showed high herbicidal activity to main dominant weeds occurring in rice field without the serious rice injury.

• Tribology and Lubricants
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• v.36 no.6
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• pp.371-377
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• 2020

In In this study, we compared the results of a ball bearing life prediction model based on rolling element loads with the results of fatigue life prediction of ball bearings when a stress-based contact fatigue life prediction technique is applied to the ball bearing. We calculate the load acting on each rolling element by the external load of the bearing and apply the result to the Lundberg-Palmgren (LP) theory to calculate ball bearing life based on the rolling element. We also calculate stress-based ball bearing life through contact and fatigue analyses based on contact modeling of the ball and raceway while considering the fatigue test results of AISI 52100 steel. In stress-based life prediction, we use three high-cycle fatigue-determination equations that can predict the fatigue life when multi-axis proportional loads such as rolling-slide contact conditions are applied. These equations are derived from the stress invariant and critical plane methods and the mesoscopic approach. Life expectancy results are compared with those of the LP model. Results of the analysis indicated that the fatigue life was predicted to be lower in the order of the Crossland, Dang Van, and Matake models. Of the three, the Dang Van fatigue model was found to be the closest to the LP life.

• Electronics and Telecommunications Trends
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• v.10 no.3 s.37
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• pp.183-189
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• 1995

최근 통신서비스의 보급확대에 따른 통신용 단말기의 수요가 증가하고 있으나 단말기 용 핵심 부품인 서큘레이터를 전량 수입에 의존하고 있다. 본 고에서는 페라이트 재료 개발 및 측정, 접함 서큘레이터, 서큘레이터의 결합방법, 회전자의 평판 회로에 대한 수치해석, 주파수 선택의 한계, GaAs 복합물, Si에 사용하는 반도체 기술을 이용한 응용기술, 페라이트 구조에 가격과 크기를 줄이기 위하여 보다 간단한 단일체 회로를 제시 그리고 새로운 구조 연구와 정확한 설계에 대한 이론 연구가 활발히 진행되고 있는 유럽, 미국 일본의 기술동향과 문제점 및 대책을 기술하였다.

• Journal of the Microelectronics and Packaging Society
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• v.6 no.1
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• pp.65-73
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• 1999

Si-tip FEAs were fabricated by a lift-off based process and their operating properties were evaluated. The dependence of emission current on applied gate and anode voltages, maximum emission current, hysteresis phenomena, MOSFET-type curves, current fluctuation, light emission from the emitted electrons, and failure mechanism of the device were widely discussed based on the experimental results.

• 한국전산유체공학회:학술대회논문집
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• 2004.03a
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• pp.196-201
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• 2004

Aerodynamic characteristics of three-dimensional wings in ground effect for Aero-levitation Electric Vehicle(AEV) are numerically investigated for various ground clearances and wing spans at the Reynolds number of $2\times10^6$. Numerical results show that a sizeable three-dimensional flow separation occurs with formation of an arch vortex at the junction of main and vertical wings, and that this is conjectured a primary cause for the high lift-to-drag(L/D) reduction rate of the main wing, when the wing span is decreased. Improvements on L/D ratios of the wings with small spans are pursued by breaking the coherence of superimposed adverse pressure gradients at the wing junction.

• The Korean Journal of Pesticide Science
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• v.3 no.3
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• pp.68-70
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• 1999

Hexahydro-1,2-bertzisoxazol-4-ols prepared from the diastereoselective reductions of 3-aryl-3a,4,5,6,7,7a-hexahydro-1,2-benzisoxazol-4-ones were reacted with benzyl chloride in the presence of sodium hydride to give new 4-benzyloxy-3a,4,5,6,7,7a-hexahydro-1,2-benzisoxazoles, which showed good herbicidal activity together with excellent selectivity on rice under submerged paddy conditions.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.12
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• pp.1087-1090
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• 2003

The circular cavity resonator which can measure the dielectric properties of dielectrics in the V -band(50㎓∼75㎓) frequency range was designed and fabricated. Exciting and detecting of the resonator is performed by WR15 rectangular waveguides using Bethe's small hole coupling. GaAs and PTFE plate samples were used for the verification of the performance of the fabricated circular cavity resonator. In the measurement of GaAs and PTFE using that resonator, the permittivity were measured as I2.87 and 2.14, respectively.

• 한국전산유체공학회:학술대회논문집
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• 2005.04a
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• pp.57-64
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• 2005

Aerodynamic characteristics of three-dimensional wings in ground effect for Aero-levitation Electric Vehicle(AEV) are numerically investigated for various fairing shapes at the junctions of 3D Wings. Numerical results show that a sizeable three-dimensional comer flow separation occurs with formation of an arch vortex at the junction of main and vertical wings, and also that this is predicted the main cause of the high lift-to-drag(L/D) reduction rate of the main wing. To avoid the comer flow separation, the main idea of this study is to reduce the cross section gradient of the comer flow tube near the trailing edge for various fairing shapes. Improvements on L/D ratios of the wings are pursued by breaking the coherence of superimposed adverse pressure gradients at the wing junction when the cross section gradient is changed slowly at the trailing edge.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.135-138
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• 2003

The circular cavity resonator which can measure the dielectric properties of dielectrics in the V-band($50GHz{\sim}75GHz$) frequency range was designed and fabricated. Exciting and detecting of the resonator is peformed by WR15 rectangular waveguides using Bethe's small hole coupling. The GaAs plate sample was used for the verification of the performance of the fabricated circular cavity resonator. In the measurement of GaAs single crystal using that resonator, the resonant frequency of the dominant $TE_{011}$ mode, the permittivity and $Q{\times}f_0$ were measured as 53.29GHz, 12.87 and 138,000, respectively.