• 한국통신학회논문지
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• 제25권10B호
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• pp.1701-1706
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• 2000

본 연구에서 GaAs pHEMT와 도파관-마이크로스트립 변환구조를 이용하여 38 GHz 대역 하이브리드 전력증폭기 모듈이 개발되었다. 10 mil duroid 기판이 전력증폭가와 도파관-마이크로스트립 변환구조 제작에 사용되었다. 제작된 도파관-마이크로스트립 변환구조는 32 - 40 GHz 대역까지 약 I dB 삽입손실(back to back)의 측정 결과를 보였다. 전력증폭기 모듈의 측정 결과, 36.8 - 38.5 GHz에서 대략 출력 전력 29 dBm(P1.5 dB), 전력 이득은 7.2 dB, PAE 는 11.2 % 였다.

• Current Optics and Photonics
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• 제1권2호
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• pp.150-156
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• 2017

A diffraction limited optical system for head mounted displays (HMDs) was designed. This optical system consists of four modules, including 1:5 mm and 5:30 mm beam expanders, polarization grating-polarization conversion system (PG-PCS) and refractive/diffractive projection optical module. The PG-PCS module transforms the unpolarized Gaussian beam to a linearly polarized beam and it simultaneously homogenizes the spatial intensity profile. The optical projector module has a $30^{\circ}$ field of view, a 22 mm eye relief, and a 10 mm exit pupil diameter with a compact structure. Common acrylic materials were utilized in the optical design process; therefore, the final optical system was lightweight. The whole optical system is suitable for a 0.7 inch liquid crystal on silicon microdisplay (LCOS) with HDTV resolution ($1920{\times}1080$) and $8.0{\mu}m$ pixel pitch.

• 반도체디스플레이기술학회지
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• 제15권2호
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• pp.55-60
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• 2016

This study was developed through the secondary battery module charging/discharger possible utilization in the production process equipment circuit. The developed module is ensuring construction of efficient and productive charging and discharger through this research a limit on the yield and the price of existing single -channel charge and discharger circuit as a 5V 70A grade secondary battery Formation charge and discharger for up to 1 board 4 channels. In order to improve the sensing accuracy, through a robust differential amplifier circuit described using 16bit Analog-Digital Converter and noise was secured 16bit resolution sensing. The configuration also made demands for property Rise / Fall Time. Data Acquisition, discharge efficiency and also to fit the sink circuit temperature level for mass production.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 전력전자학술대회 논문집
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• pp.475-476
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• 2013

In single-phase flyback inverter for grid-connected PV-AC module, power ripple is occurred as two times grid frequency on input capacitor. So, decoupling method has attracted interest recently. Also, power generation of PV depending on irradiation is limited at particular time, so use of energy storage system can increase energy efficiency. In this paper, flyback inverter for grid-connected PV-AC module which can operate decoupling and energy storage functions is proposed and verified by PSIM simulation.

• 대한기계학회논문집
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• 제18권1호
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• pp.12-23
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• 1994

This paper proposes an optimal design software for the open-chain dynamic systems whose governing equations are expressed as differential equation. In this software, an input module and an automatic creation module of the equation of motion are developed to contrive the user's convenience. To analyze the equation of motion of the dynamic systems, variable-order and variable-stepsize Adams-Bashforth-Moulton predictor-corrector method is used to improve the efficiency. For the optimization and the design sensitivity analysis, ALM(augmented lagrange multiplier)method and adjoint variable method are adopted respectively. An output module with which the user can compare and investigate the analysis and the optimization results through tables and graphs is also provided. The developed software is applied to three typical dynamic response optimization problems, and the results compare very well with those available in the literature, demonstrating its effectiveness.

• Journal of Electrical Engineering and Technology
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• 제9권4호
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• pp.1269-1276
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• 2014

The main objective of this paper is to design DC-DC MPPT circuit using chaotic pulse width modulation to track maximum power from solar PV module for space application. The direct control method of tracking is used to extract maximum power. The nominal duty cycle of the main switch of DC-DC SEPIC converter is adjusted so that the solar panel output impedance is equal to the input resistance of the SEPIC converter which results better spectral performance in the tracked voltages when compared to conventional PWM control. The conversion efficiency of the proposed MPPT system is increased when CPWM is used as a control scheme

• 전력전자학회:학술대회논문집
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• 전력전자학회 2015년도 전력전자학술대회 논문집
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• pp.289-290
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• 2015

본 논문에서는 고효율, 저가격의 400W급 태양광 Module Integrated Converter (MIC)를 소개한다. 제안하는 MIC는 Interleaved flyback 토폴로지를 기반으로, 계통 주기 내에서 DCM과 CCM의 모든 동작 영역을 활용할 수 있게 설계되어 도통 손실 및 전력 용량을 개선한다. 또한 새로운 출력 제어 전류 알고리즘을 통해 기존의 Flyback의 CCM 영역에서의 제어문제를 해결하여 개발된 Flyback MIC의 실효성을 획득한다. 최종적으로 400W급 시제품을 제작하여 타당성 검증 및 결과를 제시한다.

• 소성∙가공
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• 제17권6호
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• pp.407-411
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• 2008

A brake system in automobile is one of the important parts that directly affect the safety of passengers. Particularly, disk brake module is applied to almost all kinds of automobile brake system due to its remarkable braking power and braking distance. In the disk brake module of an automobile, the bolt for tire wheel is assembled to the disk brake hub by interference fit(bolt pressing process). The process induces small deformation whose range is within tens of ${\mu}m$ and this deformation may cause the runout badness of the whole disk brake module, and even braking problems such as judder or squeal phenomena which makes the loss of braking efficiency. In this study, bolt pressing fit into hub was simulated by $ANSYS^{TM}$, a commercial structure analysis program. Also, the aspect and the cause of hub displacement were analyzed and the solution for decreasing runout of hub was proposed.

• 한국정보기술학회 영문논문지
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• 제8권2호
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• pp.111-118
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• 2018

Information communication authority module software contains various functions and services. A software test is the only acceptance test step. Recently, however, all development steps have become important. In particular, the software acceptance step is very high, and a study of the effective use of limited time and resources on acceptance step is needed. This study examined the efficiency of the Test Design Technique for Software Test. The proposed Test Design process was applied to the domain systems of info-communication and the degree of improvement was measured. This paper establishes Software Test design process Infrastructure based on the developed software.

• 전력전자학회논문지
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• 제24권5호
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• pp.356-364
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• 2019

In this study, major problems, such as licensing problems due to civil complaints, deterioration of facility period, and damage of modules, are exposed to many problems in domestic businesses. Particularly, the photovoltaic (PV) modules applied to early PV systems have been repaired and replaced over the past two decades, and a new module-based aging detection method is needed to expand the maintenance market and stabilize and repair power supplies. PV modules in a PV system use a string that is configured in series to generate high voltage. However, even if only one module of the solar modules connected in series ages, the power generation efficiency of the aged string is reduced. Therefore, we propose a topology that can measure the instantaneous PV characteristic curve to determine the aging module in the solar string and the aging judgment algorithm using the measured PV characteristic curve.