• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2002년도 종합학술발표회 논문집 Vol.12 No.1
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• pp.141-145
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• 2002

In this paper, we have implemented the reflection type band-rejection filter by employing the 3-㏈ hybrid and the frequency-selective loads. The frequency-selective loads have been achieved with the 3-pole bandpass filter terminated by a 50-ohm load. The reflection type band-rejection filter is less sensitive to unloaded Q-factor of resonator than the conventional one. Measurements and simulations on the presented band-rejection filter in this paper show the excellent performances in passband and rejection-band.

• Journal of Power Electronics
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• 제19권5호
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• pp.1289-1302
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• 2019

In this paper, an optimal allocation method of a hybrid active power filter in an active distribution network is designed based on the differential evolution algorithm to resolve the harmonic generation problem when a distributed generation system is connected to the grid. A distributed generation system model in the calculation of power flow is established. An improved back/forward sweep algorithm and a decoupling algorithm are proposed for fundamental power flow and harmonic power flow. On this basis, a multi-objective optimization allocation model of the location and capacity of a hybrid filter in an active distribution network is built, and an optimal allocation scheme of the hybrid active power filter based on the differential evolution algorithm is proposed. To verify the effect of the harmonic suppression of the designed scheme, simulation analysis in an IEEE-33 nodes model and an experimental analysis on a test platform of a microgrid are adopted.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권8호
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• pp.377-386
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• 2005

This paper presents the control algorithm of single-phase hybrid active power filter for the compensation of harmonic current components in nonlinear R-L load with passive active Power filters. To construct two phase system, an imaginary second phase was made. In this proposed method, the new signal which is the delayed through the filtering by the phase-delay property of low-pass filter is used as the secondary phase. Because two-phases have the different phase, the instantaneous calculation of harmonic current is possible. In this paper, a reference voltage is created by multiplying the coefficient k by the compensation current using the rotating reference frame synchronized with the source-frequency, not applying to instantaneous reactive power theory which has been used with the existing fixed reference frames In order to verify the validities of the proposed control methods, experiments are carried out with the prototypes of single-phase hybrid active power filter.

• International Journal of Aeronautical and Space Sciences
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• 제18권3호
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• pp.535-544
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• 2017

In-flight aircraft engine performance estimation is one of the key techniques for advanced intelligent engine control and in-flight fault detection, isolation and accommodation. This paper detailed the current performance degradation estimation methods, and an improved hybrid Kalman filter via velocity-based LPV (VLPV) framework for these needs is proposed in this paper. Composed of a nonlinear on-board model (NOBM) and VLPV, the filter shows a hybrid architecture. The outputs of NOBM are used for the baseline of the VLPV Kalman filter, while the system performance degradation factors on-line estimated by the measured real system output deviations are fed back to the NOBM for its updating. In addition, the setting of the process and measurement noise covariance matrices' values are also discussed. By applying it to a commercial turbofan engine, simulation results show the efficiency.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1450-1455
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• 2005

This paper describes a DR construction for land navigation and the sigma point based receding horizon Kalman FIR (SPRHKF) filter for DR/GPS hybrid navigation system. A simple DR construction is adopted to improve the performance both of the pure land DR navigation and the DR/GSP hybrid navigation system. In order to overcome the flaws of the EKF, the SPKF is merged with the receding horizon strategy. This filter has several advantages over the EKF, the SPKF, and the RHKF filter. The advantages include the robustness to the system model uncertainty, the initial estimation error, temporary unknown bias, and etc. The computational burden is reduced. Especially, the proposed filter works well even in the case of exiting the unmodeled random walk of the inertial sensors, which can be occurred in the MEMS inertial sensors by temperature variation. Therefore, the SPRHKF filter can provide the navigation information with good quality in the DR/GPS hybrid navigation system for land navigation seamlessly.

• 한국컴퓨터정보학회논문지
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• 제19권8호
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• pp.27-34
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• 2014

이 논문에서는 hybrid projection 함수와 rank order 필터를 이용하여 눈동자를 검출하는 방법을 제안한다. 눈썹을 눈동자로 검출하는 오류를 줄이기 위하여, hybrid projection 함수를 이용하여 얼굴 영역에서 눈썹을 검출하고 눈썹이 포함되지 않도록 눈 영역을 설정한다. 눈 영역에서 rank order 필터를 사용하여 눈동자 후보점을 찾고 위치를 보정한다. 두 눈동자 후보점을 기하학적인 제약조건을 기반으로 쌍으로 묶고 각 쌍의 두 눈에 대한 유사도를 정합을 이용하여 측정하여가장작은값을 갖는 쌍을 최종눈동자로 결정한다. BioID 얼굴데이터베이스의 얼굴 영상 700개에 대한 실험 결과 92.4%의 검출율을 얻었으며 기존 방법보다 약 21.5% 개선된 결과를 얻었다.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.207-216
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• 2017

Wind energy conversion systems (WECS) which consist of wind turbines with permanent magnet synchronous generator (PMSG) and full-power converters have become widespread in the field of renewable power systems. Generally, conventional diode bridge rectifiers have used to obtain a constant DC bus voltage from output of PMSG based wind generator. In recent years, together advanced power electronics technology, Pulse Width Modulation (PWM) rectifiers have used in WECS. PWM rectifiers are used in many applications thanks to their characteristics such as high power factor and low harmonic distortion. In general, L, LC and LCL-type filter configurations are used in these rectifiers. These filter configurations are not exactly compensate current and voltage harmonics. This study proposes a hybrid passive filter configuration for PWM rectifiers instead of existing filters. The performance of hybrid passive filter was tested via MATLAB/Simulink environment under various operational conditions and was compared with LCL filter structure. In addition, neuro-fuzzy controller (NFC) was preferred to increase the performance of PWM rectifier in DC bus voltage control against disturbances because of its robust and nonlinear structure. The study demonstrates that the hybrid passive filter configuration proposed in this study successfully compensates current and voltage harmonics, and improves total harmonic distortion and true power factor.

• 제어로봇시스템학회논문지
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• 제21권11호
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• pp.1057-1063
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• 2015

This paper proposes a new nonlinear filtering algorithm that combines the unscented Kalman filter (UKF) and the finite impulse response (FIR) filter. The proposed filter is called the unscented Kalman/FIR hybrid filter (UKFHF). In the UKFHF algorithm, the UKF is used as the main filter, which produces state estimates under ideal conditions. When failures of the UKF are detected, the FIR filter is operated. Using the output of the FIR filter, the UKF is reset and rebooted. In this way, the UKFHF recovers from failures. The proposed UKFHF is applied to indoor human localization using wireless sensor networks. Through simulations, the performance of the UKFHF is demonstrated in comparison with that of the UKF.

• 대한임베디드공학회논문지
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• 제10권6호
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• pp.373-379
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• 2015

A hybrid navigation system is implemented to apply for a mobile robot. The hybrid navigation system consists of an inertial navigation system and a global positioning system. The inertial navigation system quickly calculates the position and the attitude of the robot by integrating directional accelerations, angular speed, and heading angle from a strap-down inertial measurement unit, but the results are available for a short time since it tends to diverge quickly. Global positioning system delivers position, heading angle, and traveling speed stably, but it has large deviation with slow update. Therefore, a hybrid navigation system uses the result from an inertial navigation system and corrects the result with the help of the global positioning system where an indirect feedback Kalman filter is used. We implement and confirm the performance of the hybrid navigation system through driving a car attaching it.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년 학술대회 논문집 정보 및 제어부문
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• pp.388-390
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• 2006

This paper presents a hybrid SoC design for phase detection of single tone signal. The designed hybrid SoC is composed of three functional blocks, i.e., an analog to digital converter module, a phase detection module and a controller module. A design of the controller module is based on a 16-bit RISC architecture. An I/O interface and an LCD control interface for transmission and display of phase measurement values are included in the design of the controller module. A design of the phase detector is based on a recursive sliding-DFT. The recursive architecture effectively reduces the gate numbers required in the implementation of the module. The ADC module includes a single-bit second-order sigma-delta modulator and a digital decimation filter. The decimation filter is designed to give 98dB of SNR for the ADC. The effective resolution of the ADC is enhanced to 98dB of SNR by the incorporation of a pre FIR filter, a 2-stage cascaded integrator- comb(CIC) filter and a 30-tab FIR filter in the decimation. The hybrid SoC is verified in FPGA and implemented in 0.35 CMOS Technology.