• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1561_1562
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• 2009

In this paper, designed triple-band antenna of PIFA(Planar Inverted-F Antenna) structure with U-slot. We designed optimal PIFA structure using Evolution Strategy(ES) about two U-slot parameters. We materialized API(Application Program Interface) about EM simulator and Excel using VB(Visual Basic). The result of ES for triple-band PIFA are resonant frequency of 430MHz, 910.5MHz, 2458.5MHz.

• 대한기계학회논문집
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• 제19권1호
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• pp.99-110
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• 1995

An industrial robot needs a simple and robust control algorithm obtaining high precision control performance in spite of disturbance and parameter's change. In this paper, for solving this problem, a new sliding mode control algorithm is proposed and applied to the trajectory control of a SCARA type robot. The proposed algorithm has diminished the chattering occurring in sliding mode by setting a dead band along the switching line on the phase plane. It shows that we can easily obtain a simple switching control input satisfying sliding mode in spite of regarding nonlinear terms of a manipulator and servo system as disturbance. A guideline for selection of dead-band width is determined by optimal value of cost function presenting magnitudes of chattering and error. By this algorithm, we can expect the high performance of the trajectory tracking of an industrial robot which needs a robust and simple algorithm.

• 지구물리
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• 제4권4호
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• pp.297-311
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• 2001

WDM(Wavelength Division Multiplexing) 광동신망의 노드에서 신호채널들이 분기 결합될때 잔류채널들의 이득을 일정하게 제어해 주기 위해 고정이득 EDFA를 사용한다. 본 논문에서는 양방향 펌프에 의해 고이득을 가지는 L-band EDFA에서 발진광에 의해 입력변화를 보상해주는 방식으로 고정이득 EDFA를 구현하였다. 여기서 발진방향 및 파장에 따른 잔류채널의 과도 응답 특성에 있어서 단파장 후방발진의 경우가 최적임을 확인할 수 있었다.

• 전자공학회논문지D
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• 제34D권5호
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• pp.7-13
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• 1997

A X-band 3-stage monolithic LNA (low noise amplifier) with series feedback has been successfully desined and demonstrated by suign 0.5-$\mu\textrm{m}$ GaAs MESFET. In the design of the 3-stage LNA, the effects of series feedback to the noise figure, the gain, and the stability have been investigated ot find the optimal short stub length. As a result, the inductive series feedback topology which has 10degree short stub in the GaAs MESFET source lead, has been employed in the 1-st stage. The fabricated MMIC LNA's chip size is only 1mm$^{2}$/stage, which is smaller than the previously reported X-band MMIC input/output return losses are less than -10dB and -15dB, respectively. The noise figure (NF) is less than 2.6dB. The measured data show good agreement with the simulated values.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.423-427
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• 2003

In this paper, LTCC stacked patch antenna with a radial CPW fed slot and grounded-shorting vertical-via wall for 19GHz band wireless LAN is presented. Suggested antenna employed a patch and grounded-shorting vertical-via wall for radiation element, consist of feeding structure which a radial open feature at the end of the CPW feed line. The optimal design parameters of the antenna using by EM simulation program. We can see that enough to bandwidth 560MHz for 19GHz band WLAN antenna specification by the optimized antenna.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2018년도 전력전자학술대회
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• pp.63-65
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• 2018

This paper presents a DTC-PWM(Direct Torque Control-Pluse Width Modulation) method of PMSM(Permanent Magnet Synchronous Motor) using the flux-torque hysteresis band. In order to keep the flux and torque error of the PMSM within the hysteresis band, the optimal PWM duty ratio is calculated by the error of the flux and torque with the flux and torque vector of the selected voltage vector. According to the flux duty ratios and the torque duty ratios, the optimized duty ratio to reduce the errors is selected by the calculated duty ratios. In the proposed method, the selected voltage vector is divided into d-q axis components with a simple method. And the flux duty ratios and torque duty ratios are estimated by the applied voltage vector. The proposed DTC-PWM for PMSM was verified by computer simulation.

• 한국군사과학기술학회지
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• 제14권6호
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• pp.1144-1150
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• 2011

In this paper, we present methods to improve output flatness of Ultra-wideband(f1~80f1) Frequency Generator (UFG) with variable output function. That include optimal structure and output ripple calibration algorithm to realize good flatness. The UFG was manufactured by our methods, then experiments were performed. The flatness of band 1~3 and band 4 are within ${\pm}2dB$, ${\pm}4dB$ respectively. These results are very excellent in view of ultra-wideband including millimeter wave band. From this results, we can confirm the validity of our methods.

• 공학논문집
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• 제5권1호
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• pp.119-133
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• 2004

WDM(Wavelength Division Multiplexing) 광통신망의 노드에서 신호채널들이 분기 결합될 때 잔류채널들의 이득을 일정하게 제어해 주기 위해 고정이득 EDFA를 사용한다. 본 논문에서는 양방향 펌프에 의해 고이득을 가지는 L-band EDFA에서 발진광에 의해 입력변화를 보상해주는 방식으로 고정이득 EDFA를 구현하였다. 여기서 발진방향 및 파장에 따른 잔류채널의 과도응답 특성에 있어서 단파장 후방발진의 경우가 최적임을 확인할 수 있었다.

• 대한의용생체공학회:의공학회지
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• 제14권2호
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• pp.137-145
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• 1993

Time domain analysis as well as frequency domain analysis of signal conditioning filters is very useful for practical applications. Time domain analysis of digital filters for noise cancelling in ECG signals is presented. Several band pass and band reject filters are designed for the analysis. Computer simulations are performed to compare the distortions of the Butterworth type filters and linear phase optimal FIR filters which are widely used for ECG signal processing. Band reject filters are applied to power line interference cancelling in ECG signals.

• Journal of Positioning, Navigation, and Timing
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• 제13권2호
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• pp.149-158
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• 2024

Global Navigation Satellite System (GNSS) receivers are becoming increasingly sophisticated, equipped with advanced features and precise specifications, thus demanding efficient and high-performance hardware platforms. This paper presents the design and implementation of a Field-Programmable Gate Array (FPGA)-based GNSS receiver development platform for multi-band signal processing. This platform utilizes a FPGA to provide a flexible and re-configurable hardware environment, enabling real-time signal processing, position determination, and handling of large-scale data. Integrated signal processing of L/S bands enhances the performance and functionality of GNSS receivers. Key components such as the RF frontend, signal processing modules, and power management are designed to ensure optimal signal reception and processing, supporting multiple GNSS. The developed hardware platform enables real-time signal processing and position determination, supporting multiple GNSS systems, thereby contributing to the advancement of GNSS development and research.