• Journal of the Korean Society for Precision Engineering
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• v.26 no.6
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• pp.74-80
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• 2009

Path tracking of unmanned vehicle is a basis of autonomous driving and navigation. For the path tracking, it is very important to find the exact position of a vehicle. GPS is used to get the position of vehicle and a direction sensor and a velocity sensor is used to compensate the position error of GPS. To detect path lines in a road image, the bird's eye view transform is employed, which makes it easy to design a lateral control algorithm simply than from the perspective view of image. Because the driving speed of vehicle should be decreased at a curved lane and crossroads, so we suggest the speed control algorithm used GPS and image data. The control algorithm is simulated and experimented from the basis of expert driver's knowledge data. In the experiments, the results show that bird's eye view transform are good for the steering control and a speed control algorithm also shows a stability in real driving.

• Journal of Power Electronics
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• v.18 no.6
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• pp.1805-1818
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• 2018

This paper proposes a novel hybrid maximum power point tracking (MPPT) algorithm combining a Whale Optimization Algorithm (WOA) and the conventional Perturb & Observation (P&O) to track/extract the highest amount of power from a solar photovoltaic (SPV) system working under partial shading conditions (PSCs). The proposed hybrid algorithm is based on a WOA which predicts the initial global peak (GP) and is followed by P&O in the final stage to achieve a quicker convergence to a GP. Thus, this hybrid algorithm overcomes the computational burden encountered in a standalone WOA, grey wolf optimization (GWO) and hybrid GWO reported in the literature. The conventional algorithm searches for the maximum power point (MPP) in the predicted region by the WOA. The proposed MPPT technique is modelled and simulated using MATLAB/Simulink for simulating an environment to check its effectiveness in accurately tracking the MPP during the GP region. This hybrid algorithm is compared with a standalone WOA, GWO and hybrid GWO. From the simulating results, it is shown that the proposed algorithm offers high tracking performance and that it increases the output power level of a SPV system under partial shading. The algorithm also verified experimentally on various PSCs.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.153-155
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• 2007

Korea Meteorological Administration (KMA) has operationally produced Atmospheric Motion Vector (AMV) from the consecutive MTSAT-1R satellite image dataset. Comparing with radiosonde data, our current AMV scheme shows more than 10 m/s RMSE. Therefore we need to improve continuously its accuracy. Many AMV producers have stated that the bad performance of the Height Assignment (HA) algorithm is the main reason of degrading the accuracy of AMV. The uncertainties in AMV HA can occur in the algorithm itself, used NWP profiles, and the performance of Radiative Transfer Model (RTM) etc. This study introduces currently operated AMV HA schemes and the impacts of NWP profile data and RTM that these schemes use were investigated. Finally we analyzed the relationship between vectors by vector tracking and heights assigned to each vector by using collocated wind profile dataset with radiosonde data. This study is a preliminary work to improve the accuracy of AMV by removing or decreasing the uncertainties in AMV estimation.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.14-19
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• 1993

In this paper, we proposed an indirect learning and direct adaptive control schemes using neural networks, i.e., composite adaptive neural control, for a class of continuous nonlinear systems. With the indirect learning method, the neural network learns the nonlinear basis of the system inverse dynamics by a modified backpropagation learning rule. The basis spans the local vector space of inverse dynamics with the direct adaptation method when the indirect learning result is within a prescribed error tolerance, as such this method is closely related to the adaptive control methods. Also hash addressing technique, similar to the CMAC functional architecture, is introduced for partitioning network hidden nodes according to the system states, so global neuro control properties can be organized by the local ones. For uniform stability, the sliding mode control is introduced when the neural network has not sufficiently learned the system dynamics. With proper assumptions on the controlled system, global stability and tracking error convergence proof can be given. The performance of the proposed control scheme is demonstrated with the simulation results of a nonlinear system.

• Journal of Mechanical Science and Technology
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• v.15 no.4
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• pp.433-440
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• 2001

A new design of the sliding mode control is proposed for the uncertain linear time-varying second order system. The proposed control drives system states to the target point in the minimum time with specified ranges of parametric uncertainties and disturbances. One of the advantages of the proposed control scheme is that the control inputs do not go beyond saturation limits of the actuators. The other advantage is that the minimum arrival time and the acceleration of the second order actuators system can be estimated with given parametric bounds and can be expressed in the closed from; conversely, the designer can select actuators based on the condition of the minimum arrival time to the target point. The superior performance of the proposed control scheme to other sliding mode controllers is validated by computer simulations.

• Journal of the Korea Safety Management & Science
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• v.4 no.1
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• pp.69-80
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• 2002

최근 컴퓨터 기술의 발전과 함께 Mobile 컴퓨터 환경도 함께 급속히 발전하고 있다. 이로 인해 오프라인 컴퓨팅 및 네트워킹을 이용하던 사용자들이 Mobile 컴퓨팅 환경을 자주 이용하게 되고, Mobile 솔루션에 대한 사용자의 요구도 다양화되고 있는 추세이다. 이 중 Mobile 지도 서비스는 휴대하기 편한 Pocket PC라고도 불리는 PDA(Personal Digital Assistants)는 자신의 현재 위치를 확인할 수 있는 GPS(Global Positioning System)가 급속도로 보급됨으로써 Mobile 환경에서 가장 활용도가 높은 서비스로 부각되고 있다. 가까운 미래의 IT기술은 GPS와 PDA 등을 연계한 e포지션의 폭발적인 이용 증대와 국내 원천기술에 의한 세계적인 사업모델의 탄생이 눈앞에 현실로 다가오고 있다는 점을 감안하면, GPS를 활용한 Mobile 기술력 확보는 국가적 차원에서 대단히 중요하다는 견지를 같이하는 전문가들이 많다. 이러한 시대적 요구 환경 하에서, 본 논문에서는 JAVA VM 기반의 무선위치추적 제어미들웨어와 GIS 프로그램(Vector MAP Viewer)을 구축함으로써 APTS의 효율성에 관한 연구를 제안하고, 앞으로의 향후 개선방향을 제시하고자 한다.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2753-2755
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• 2000

In this paper, the robust position tracking cotroller for a brushless DC motor driving a one-link robot manipulator is proposed. By using the backstepping approach, the adaptive and robust controller is appropriately designed to ensure global stability. The proposed robust backstepping controller can compensate for estimation errors in system parameters in the system with no structural changes in the controller and without destruction of the stability. The closed-loop stability of the system is shown using Lyapunov techniques. The tracking errors are shown to be globally uniformly bounded.

• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.525-528
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• 2002

This study describes an implementation of object tracking algorithm on FPGA. The global system detect the zone there is more motion in, attending to the generated optical flow, and centers its attention to it to improve the details In this case, To obtain image in Camera, Image aquisition board make use of SAA7113 Video Input processor and algorithm is applied to motion estimation and difference picture. Also, This work can be applied kalman filter to reliability of tracking.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.186-189
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• 2015

최근 GPS가 탑재된 스마트폰의 보급이 늘어나면서 위치 기반 서비스가 빠르게 성장해 왔다. 위치조회의 방법은 크게 GPS를 이용한 위치 조회 서비스, 네트워크 위치 조회 서비스, 하이브리드 위치조회 서비스가 있다. 사용자 또는 제 3자가 위치 조회를 요청하였을 경우 사용자의 스마트폰에 장착된 소형 GPS 모듈을 조회하여 제공하여 준다. 하지만 GPS 모듈의 경우 실내에서는 취약하므로 만약 조회한 스마트폰의 위치가 실내에 있다면 Wi-Fi, 모바일 네트워크를 이용하여 위치를 조회하여 제공한다. 본 논문에서는 GPS 기반 위치 조회, 네트워크 기반 위치 조회, 하이브리드 위치 조회를 소개 및 비교 분석한다.

• Journal of Korea Multimedia Society
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• v.21 no.5
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• pp.545-557
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• 2018

The Global Positioning System (GPS) has become popular and widely used in many fields from military to civilian applications. However, GPS signals are suffered from interference due to its weak signal over wireless channel. There are many types of interference, such as jamming, blocking multipath, and spoofing, which can mislead the operation of GPS receiver. In this paper, vector-based tracking loop model with integrity check is proposed to detect and mitigate the harmful effect of interference on GPS receiver operation. The suggested methods are implemented in the tracking loop of GPS receiver. As a first method, integrity check with carrier-to-noise ratio (C/No) monitoring technique is applied to detect the presence of interference and prevent contaminated channels out of tracking channels to calculate position. As a second method, a vector-based tracking loop using Extended Kalman Filter with adaptive noise covariance according to C/No monitoring results. The proposed methods have been implemented on simulated dataset. The results demonstrates that the suggested methods significantly mitigate interference of Additive White Gaussian Noise (AWGN) and improve position calculation by 44%.