• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1178-1180
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• 1987

The resequence delay is an important performance measure in a store-and-forword computer network where messages go out of order while traversing logical channel. An analysis of the total delay including resequence delay is presented for M/M/L queueing system with 2 class heterogeneous servers and improvement of delay performance is investigated by simulation.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1210-1212
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• 1987

Adaptive control for robot manipulator controller has been considered as an effective approach because robot dynamic models contain the nonlinearities and uncertainties. This paper present an approach for the position and velocity control of a manipulator by using the seif-tuning type controller for each point. The complicated model manipulator system is modeled by a set of time series difference equation. The parameters of the models are determined by online recursive algorithms. Finally some remarks on the effectiveness and applications of adaptive controller are discussed.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.1933-1934
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• 2006

이 논문은 비강체 객체에 대한 실시간 추적시 다른 객체에 의한 간섭의 영향을 줄이는 방법을 제시한다. 제시한 방법에서 객체 추적에 대한 알고리즘은 현재 프레임에서 확률적으로 목표의 위치를 찾는 Mean shift 방법에 기초를 두고 있다. 기존의 방법에서는 mean shift 의 파라미터로서 색분포만 사용한다. 하나의 파라미터에만 의존하므로 같은 색분포를 갖는 다른 객체가 추적 영역 내에 들어오게 되면 새로운 객체를 기존 객체로 인식하게 되는 문제가 발생한다. 여기서 우리는 강인한 객체추적을 하기 위해 다른 하나의 파라미터로서 거리정보를 이용을 제안한다. 거리정보에 최적화된 흐름 추정(optical flow estimation)방법을 확장 도입한 강인한 에러 기준(robust error norm) 방법을 사용하여 기존의 객체에게 더 많은 가중치를 주는 방식으로 mean shift 추적 방법을 기초로 하여 강력하게 추적하는 방법을 제안한다.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.223-225
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• 2006

A ball moving on a beam is a typical nonlnear dynamic system, which is often adopted to proof test diverse control schemes. Ball and plate system is the extension of the traditional ball and beam problem that moves a metal ball on a rigid plate. In this paper, a trajectory planning and tracking problem is proposed for ball and plate system, which is to control the ball from a point to another without hitting the obstacles. Our scheme is composed of three controllers, TS type optimal path tracking controller, mandani type obstacle avoidance controller and trajectory planning controller that determines the desired trajectory. But this type of construction can give rise to chattering executions. Because the difference of contributions from concurrent controllers can cause behaviors unsmoothly. We propose fuzzy pid supervision control1er to handle this problem.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.226-228
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• 2006

This paper is concerned with an Adaptive Fuzzy Sliding Mode Control(AFSMC) that the fuzzy systems are used to approximate the unknown functions of nonlinear system. In the adaptive fuzzy system, we adopt the adaptive law to approximate the dynamics of the nonlinear plant and to adjust the parameters of AFSMC. The stability of the suggested control system is proved via Lyapunov stability theorem, and convergence and robustness properties are demonstrated. The simulation results demonstrate that the performance is improved and the system also exhibits stability.

• Journal of Welding and Joining
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• v.10 no.1
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• pp.20-34
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• 1992

Characteristics of two correcting methods, a new Autogeneous GTAW heating (TIG) method and the conventional GMAW bead-on plate welding(MIG) method, for distorted aluminum fabrication structures were studied. As a result of microscopic study of Autogeneous GTAW heating and GMAW bead-on plate welding areas, porosities in weld metal and surface cracks in local heating zone were found. Through the mechanical tests, it was verified that porosities decrease tensile strength and surface of distortion, angular displacement and transeverse shrinkage were measures and compared. In order to investigate changes of material properties in heating area and cause of defects such thermal stresses were calculated by ADINA. Through the computations of transient thermal stresses and microscopic observation of fracture surface, thermal stress was found to be the cause of crack during Autogeneous GTAW heating.

• Journal of the Korean Institute of Intelligent Systems
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• v.10 no.5
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• pp.423-431
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• 2000

In this paper, the effect of computing time-delay in the real-time digital fuzzy control systems is investigated and the design methodology of a real-time digital fuzzy controller(DFC) to overcome the problems caused by it is presented. We propose the fuzzy feedback controller whose output is delayed with unit sampling period. The analysis and the design problem considering computing time-delay is very easy because the proposed controller is syncronized with the sampling time. The stabilization problem of the digital fuzzy control system is solved by the linear matrix inequality(LMI) theory. Convex optimization techniques are utilized to find the stable feedback gains and a common positive definite matrix P for the designed fuzzy control system Furthermore, we develop a real-time fuzzy control system for backing up a computer-simulated truck-trailer with the consideration of the computing time-delay. By using the proposed method, we design a DFC which guarantees the stability of the real time digital fuzzy control system in the presence of computing time-delay.

• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.72-75
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• 2001

In this paper, the kinematic model and motion control of a joint-actuated mobile robot are analyzed. To take an efficient approach to the wheeled mobile robots, the relationship between wheel rotation and the contact point of the wheel is considered. It is shown that each addition of a joint to a mobile robot increases the degree of freedom(DOF) of mobile robot, and the way of joint attachment to a mobile robot is proposed. To get a solution of inverse kinematics of mobile robot, two types of approaches are proposed.

• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.256-259
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• 2001

본 논문에서는 블록 삼각구조를 갖는 다변수 비선형 시스템의 상태 관측기의 설계 문제를 다룬다. 이를 위해 단일 입출력 삼각구조 시스템에 대한 기존의 설계 기법을 다변수 시스템으로 확장한다. 특히, 제안한 관측기의 이득은 시스템의 선형 부분뿐만 아니라 비선형성을 기반으로 설계되어지기 때문에 기존의 고이득 관측기에 비해 과도응답 특성을 개선한다. 또한 오차방정식에 대한 유사 변화을 이용하여 제안한 관측기가 전역 지수적 수렴성을 보임을 증명한다. 마지막으로, 시뮬레이션 예제를 통해 본 논문에서 제안한 설계 기법의 타당성을 입증한다.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1121-1122
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• 2008

By using FACS(Facial Action Coding System) and linear interpolation, a 3D facial robot simulator is developed in this paper. This simulator is based on real facial robot and synchronizes with it by unifying protocol. Using AUs(Action Unit) of each 5 basic expressions and linear interpolation makes more various dynamic facial expressions.