• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2248-2250
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• 2004

본 논문에서는 유연한 단일링크 매니퓰레이터의 끝단 위치 추적제어를 위해 웨이블렛 신경망을 이용한 강인 적응제어기를 제안한다. 전체 제어기는 웨이블렛 신경망에 의해 추정된 피드백 선형화 제어기와 그 추정오차를 보상하기 위한 보상제어기로 구성된다. 시스템의 출력값은 최소위상을 보장하기 위하여 재정의하여 사용된다. 구성된 웨이블렛 신경망의 연결 가중치는 Lyapunov 안정도 이론에 기초해서 조절된다. 제안된 제어기의 성능 향상은 PD 제어기와 비교함으로써 입증된다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.9
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• pp.1356-1362
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• 2015

Modular snake-like robots are robust for failure and have flexible locomotions for obstacle environment than of walking robot. This requires an adaptation capability which is obtained from a learning approach, but has not been analysed as well. In order to investigate the property of adaptation of locomotion for different terrains, NEAT controllers are trained for a flat terrain and tested for obstacle terrains. The input and output characteristics of the adaptation for the neural network controller are analyzed for different terrains in frequency domain.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.273-276
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• 1994

It has been known the fact that extended Kalman filter (EKF) is correctly capable of estimating system parameters and state variables by eliminating virtually all influences of structural noises, and fuzzy controller is robust to parameter variations. this paper presents a design method of Reduced-Order EKF and fuzzy controller which consists of the rotor speed and the rotor flux estimation only by measuring stator currents. Experiment results show that both the rotor speed and the rotor flux can be prominently estimated in a wide range of the speed.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.60-62
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• 2018

본 논문에서는 유도전동기의 회전자 시정수 오차에 강인한 센서리스 전차원(Full-Order) 자속(Flux) 관측기(Observer)를 제안하였다. 이 관측기는 고정자 자속과 회전자 자속을 동기좌표계상에서 추정한다. 고정자 자속에서 누설 자속을 뺀 공극 자속을 기준으로 제어를 수행하며, 동기좌표계가 공극 자속을 빠르게 따라갈 수 있는 방법을 제안하였다. 제안된 방법을 적용할 때, 기존의 회전자 자속을 직접 이용하는 방법보다 중-고속 영역에서 회전자 시정수 오차의 영향이 감소함을 확인하였다. 또한 기존 관측기와 달리 제안된 관측기에서 적응제어기(Adaptive Controller)는 전동기의 회전 주파수가 아닌, 전동기의 슬립 주파수 만을 추정하므로, 회전자 자속 오차에 민감한 적응제어기의 역할을 축소하였다. 시뮬레이션 및 실험으로 이론의 타당성 및 효과를 검증하였다.

• Journal of Semiconductor Engineering
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• v.1 no.3
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• pp.81-87
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• 2020

An instrumentation amplifier (IA) and an analog-to-digital converter (ADC) are essential circuit blocks for accurate and robust sensor readout systems. This paper introduces recent advances in radiation-hardening by design (RHBD) techniques applied for the sensor readout integrated circuits (IC), e.g., the three-op-amp IA and the successive-approximation register (SAR) ADC, operating against total ionizing dose (TID) and singe event effect (SEE) in harsh radiation environments. The radiation-hardened IA utilized TID monitoring and adaptive reference control to compensate for transistor parameter variations due to radiation effects. The radiation-hardened SAR ADC adopts delay-based double-feedback flip-flops to prevent soft errors which flips the data bits. Radiation-hardened IA and ADC were verified through compact model simulation, and fabricated CMOS chips were measured in radiation facilities to confirm their radiation tolerance.

• Advances in Energy Research
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• v.8 no.3
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• pp.175-184
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• 2022

The dual-fuel technology, which uses gaseous fuel as the main fuel and liquid as the pilot fuel, is an appealing technology for reducing the exhaust emissions. The current study proposes emission models based on ANFIS for a dual-fuel using producer gas (PG)-diesel engine. Emissions measurements were taken at different engine load levels and fuel injection timings. The proposed model predictions were examined using statistical methods. With R2 values in the range of 0.9903 to 0.9951, the established ANFIS model was found to be consistently robust in predicting emission characteristics. The mean absolute percentage deviate in range 1.9 to 4.6%, and mean squared error varies in range 0.0018 to 13.9%. The evaluation of the ANFIS model developed shows a reliable claim of intrinsic sensitivity, strength, and outstanding generalization. The presented meta-model can be used to simulate the engine's operation in order to create an efficient control tool.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.11
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• pp.1423-1433
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• 2018

Recently, a permanent magnet synchronous motor of middle and small-capacity has high torque, high precision control and acceleration / deceleration characteristics. But existing control has several problems that include unpredictable disturbances and parameter changes in the high accuracy and rigidity control industry or nonlinear dynamic characteristics not considered in the driving part. In addition, in the drive method for the control of low-vibration and high-precision, the process of connecting the permanent magnet synchronous motor and the load may cause the response characteristic of the system to become very unstable, to cause vibration, and to overload the system. In order to solve these problems, various studies such as adaptive control, optimal control, robust control and artificial neural network have been actively conducted. In this paper, an incremental encoder of the permanent magnet synchronous motor is used to detect the position of the rotor. And the position of the detected rotor is used for low vibration and high precision position control. As the controller, we propose augmented state feedback control with a speed observer and first order deadbeat disturbance observer. The augmented state feedback controller performs control that the position of the rotor reaches the reference position quickly and precisely. The addition of the speed observer to this augmented state feedback controller compensates for the drop in speed response characteristics by using the previously calculated speed value for the control. The first order deadbeat disturbance observer performs control to reduce the vibration of the motor by compensating for the vibrating component or disturbance that the mechanism has. Since the deadbeat disturbance observer has a characteristic of being vulnerable to noise, it is supplemented by moving average filter method to reduce the influence of the noise. Thus, the new controller with the first order deadbeat disturbance observer can perform more robustness and precise the position control for the influence of large inertial load and natural frequency. The simulation stability and efficiency has been obtained through C language and Matlab Simulink. In addition, the experiment of actual 2.5[kW] permanent magnet synchronous motor was verified.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.12
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• pp.1492-1499
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• 2019

This paper propose how to track the position of the observer to control the viewing zone using an adaptive parallax barrier. The pose is estimated using a Constrained Local Model based on the shape model and Landmark for robust eye-distance measurement in the face pose. Camera's correlation converts distance and horizontal location to centimeter. The pixel pitch of the adaptive parallax barrier is adjusted according to the position of the observer's eyes, and the barrier is moved to adjust the viewing area. This paper propose a method for tracking the observer in the range of 60cm to 490cm, and measure the error, measurable range, and fps according to the resolution of the camera image. As a result, the observer can be measured within the absolute error range of 3.1642cm on average, and it was able to measure about 278cm at 320×240, about 488cm at 640×480, and about 493cm at 1280×960 depending on the resolution of the image.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.5
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• pp.447-455
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• 2014

In this paper, we consider a representative integral imaging method in glasses-free 3D image processing and propose a prioritized transmission scheme for guaranteeing a received video quality in error-prone environments. According to the correlation of pixels consisting of each voxel of integral image, we set the priority differently and apply the modulation level according to this priority value. That is to say, the corresponding pixels with small variance are set to a high priority and transmitted by using a low level modulation that is robust under transmission errors, but the corresponding pixels with greater variance are set to a lower priority and transmitted by using a high level modulation that has a high bit error rate but fast transmission rate. Result shows that the proposed scheme that applies the error-robust modulation level to the important image bit stream with the high priority improves the peak to sidelobe ratio (PSR) of the received 3D image, compared with a typical method that use the same modulation level without distinction of priorities.

• Journal of the Institute of Convergence Signal Processing
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• v.12 no.1
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• pp.13-19
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• 2011

In this paper, a visual surveillance system using SOPC based NIOS II embedded processor and C2H compiler was implemented. In this system, the IP is constructed by C2H compiler for the output of the camera images, image processing, serial communication and network communication, then, it is implemented to effectively control each IP based on the SOPC and the NIOS II embedded processor. And, an algorithm which updates the background images for high speed and robust detection of the moving objects is proposed using the Adaptive Gaussian Mixture Model(AGMM). In results, it can detecte the moving objects(pedestrians and vehicles) under day-time and night-time. It is confirmed that the proposed AGMM algorithm has better performance than the Adaptive Threshold Method(ATM) and the Gaussian Mixture Model(GMM) from our experiments.