• 제어로봇시스템학회논문지
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• 제9권6호
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• pp.466-472
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• 2003

This paper describes a tracking control for the mobile robot based on fuzzy systems. Since the mobile robot has the nonholonomic constraints, these constraints should be considered to design a tracking controller for the mobile robot. One of the well-known tracking controllers for the mobile robot is the back-stepping controller. The conventional back-stepping controller includes the dynamics and kinematics of the mobile robot. The conventional back-stepping controller is affected by the derived velocity reference by a kinematic controller. To improve the performance of the conventional back-stepping controller, this paper uses the fuzzy systems known as the nonlinear controller. The new velocity reference for the back-stepping controller is derived through the fuzzy inference. Fuzzy rules are selected for gains of the kinematic controller. The produced velocity reference has properly considered the varying reference trajectories. Simulation results show that the proposed controller is more robust than the conventional back-stepping controller.

• 한국군사과학기술학회지
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• 제9권2호
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• pp.77-86
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• 2006

Usually, a tracking-gate of the tracker is used to track the target radar signal in the active ECM system. In this paper, we propose the feed-back tracking-gate filtering method. The designed method applies a tracking-gate of the tacker to the ECM system's receiver as a rejection or pass filter selected by the receiver's purpose, and the specific target signals can be passed or rejected though this tracking-gate filter. Thus, the number of input signals within the receiver's search band is minimized owing to this filter except the target signals. In conclusion, the EW equipment's reaction time can be reduced and the error value about the target signals can be lower than the previous methods'.

• 한국산업융합학회 논문집
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• 제24권3호
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• pp.301-306
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• 2021

In this paper, we propose a modified back-stepping control method in view of the dynamic model of mobile manipulator has the nonholonomic constraints, these constraints should be considered to design a tracking controller for the mobile manipulator. The conventional back-stepping controller includes the dynamics and kinematics of the mobile robot systems. and the modified adaptive back0stepping method is applied to constructing the controller. The proposed controller can realize the tracking trajectory of the reference path. The efficiency and robustness of this control method is demonstrated by the simulation.

• 제어로봇시스템학회논문지
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• 제22권10호
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• pp.869-875
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• 2016

In this paper, a novel scheme with which to mitigate a repeat-back jamming effect is proposed for the GPS L1 coarse/acquisition signal. The proposed scheme estimates the code tracking bias caused by repeat-back jamming signals using a Combined Pseudo-random noise signal. It then mitigates the repeat-back jamming effect by subtracting the estimated code timing on a normal correlation channel from the estimated value. Through a Monte-Carlo simulation, the proposed scheme can diminish the running average of code tracking bias to less than 10% of the bias using the conventional scheme.

• 융합신호처리학회논문지
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• 제2권4호
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• pp.38-45
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• 2001

본 논문에서는 히스트로그램 백 프로제션(HBP: histogram back projection); 히스트로그램 인터섹션(HI:histogram intersection )그리고 XY-프로젝션(XY-projectipn)을 이용하여 움직이는 카메라로부터 이동 물체를 추적하는 알고리즘을 제안하였다. 제안된 방법은 히스토그램 백 프로젝션을 이용하여 물체를 분할하고 히스토그램 인터섹션과 XY-프로젝션을 사용하여 추적물체를 정합하고 추출하였다. 본 논문에서는 컴퓨터 모의 실험을 통하여 제안된 방법이 움직이는 카메라로부터 획득된 영상에서 추적하고자 하는 물체를 분할하고 정합하여 큰 오차 없이 추적함을 보였다.

• 제어로봇시스템학회논문지
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• 제7권3호
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• pp.218-228
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• 2001

The switched reluctance motor(SRM) has been increasingly used in high-performance servo applications such as electric vehicles, aircraft, and direct-drive robots. The dynamic equations of SRMs are, however, highly nonlinear and this makes it difficult to control SRMs with high performance. In this paper, we propose a new robust current tracking controller for SAMs which can compensate the nonlinear characteristics of SRM(i.e., back-emf and inductance) completely and hence shows perfect tracking performance even with an arbitrary small current control loop gain. Furthermore, even in case that there exist some model uncertainties, our current controller guarantees that the stator currents can track the reference current commands with sufficiently small tracking errors. In order to justify our work, we present the tracking performance analysis and some simulation results.

• 한국컴퓨터정보학회논문지
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• 제12권3호
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• pp.185-194
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• 2007

WiBro가 IEEE802.16e로 국제 표준화 되었다. 국내뿐만 아니라 세계에서도 휴대인터넷으로 WiBro 서비스를 시작하고 있다. 본 논문에서는 불법 공격자인 해커가 휴대인터넷 WiBro의 이동단말을 이용하여 자신의 위치추적을 피하기 위하여, 피해 시스템을 직접 공격하지 않고 우회 공격을 수행한다. 현재 인터넷망에서 침입 기술에 적극적인 보안을 위한 진보된 알고리즘을 응용하여 효과적인 역추적 기법 등을 연구한다. 공격자인 이동단말에 대한 역추적을 할 때, 실시간 네트워크 로그 감사기록을 이용하고, TCP/IP와 네트워크 기반에서는 Thumbprint Algorithm, Timing based Algorithm, TCP Sequence number 등을 이용한 알고리즘 및 SWT 기법 등을 이용한 역추적 기법 등을 설계하고, 역추적을 실시하였다. 또한 트래픽 폭주 공격에 대해 AS시스템을 이용한 네트워크 트래픽 관리와 통제 및 실시간으로 역추적을 하였다. 본 논문의 연구 결과는 유비쿼터스 환경에서의 WiBro 인터넷에서의 역추적을 실시하고 포렌식 자료를 확보하는데 이바지 할 수 있을 것이다.

• 반도체디스플레이기술학회지
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• 제11권3호
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• pp.27-31
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• 2012

This paper presents a study on the design of photovoltaic system with reversal tracking reflector. The reversal tracking reflector is conceptually designed by using TRIZ. The 20 to 30% of incident rays cannot produce the current and reflected back to the glass surface because of high refractive index of solar cell which are produced from Si, GaAs. The solution of this problem has been derived using 6SC(6 steps creativity)TRIZ. The reflector which has the actuator can be trackback the sun. Reversal tracking reflector which mounted on the top of the system prevents the shadowing loss and improve the efficiency of track back function. The anti-glare reflector prevents the heat due to the concentrated reflected light rays.

• 한국위성정보통신학회논문지
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• 제8권1호
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• pp.77-82
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• 2013

최근 주목을 받고 있는 Particle Filtering은 실제 객체 추적에서 발생하는 비선형, 비 가우시안 분포를 가지는 상태 벡터의 사후확률을 추정하기 위한 Monte Carlo 시뮬레이션에 기반을 둔 추적 방법론이다. 우리는 본 논문에서 Particle Filtering을 이용한 객체 추적성능을 향상시킬 수 있는 두 가지 방법론을 제안한다. 첫 번째는 확률이 가장 낮은 샘플을 이전 프레임의 추정된 상태 벡터로 대치하는 피드백 방법론이고, 두 번째는 객체 확률 분포를 추정된 객체 후보영역에 역투영하여 신뢰구간을 구함으로써 추적 박스의 정확도를 향상시키는 방법이다. 또한, 실험을 통해 구한 추적 샘플의 진화 방정식을 제시하였다. 우리는 다양한 상황이 설정된 실험 데이터 셋을 구성하여 실험을 실시하여 제안한 방법론의 우수성을 입증하였다.

• 제어로봇시스템학회논문지
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• 제22권11호
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• pp.977-983
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• 2016

This paper proposes a novel code-tracking scheme to track the fine code synchronization for BOC (pn,n)-modulated global navigation satellite system signals in a repeat-back jamming environment. The correlation function of BOC (pn,n)-modulated signals has several peaks. The correlation function in the advanced offset region remains almost unchanged due to the repeat-back signals being received later than a line-of-sight signal in the same multipath signal receiving case. Additionally, the combined pseudo-random noise signal can be treated as repeat-back jamming signals, like multipath signals. In this paper, we propose a novel code-tracking scheme utilizing the advantages of using a combined pseudo-random noise signal in the advanced offset region and verify its performance through simulation.