The search functionality is under construction.

Author Search Result

[Author] Mignon PARK(9hit)

1-9hit
  • Robust Analysis and Design for Discrete-Time Nonlinear Systems Subject to Actuator Saturation via Fuzzy Control

    Sanghyung LEE  Euntai KIM  Hagbae KIM  Mignon PARK  

     
    PAPER-Systems and Control

      Vol:
    E88-A No:8
      Page(s):
    2181-2191

    This paper proposes an analysis and design methodology for the robust control of affine-in-control nonlinear systems subject to actuator saturation in discrete-time formulation. The robust stability condition is derived for the closed-loop system by the introduction of the fuzzy Kronecker delta. Based on the newly acquired stability condition, a design method is proposed to guarantee the robust H∞ performance. In the design, LMI-based pole placement is employed to use the freedom allowed in the selection of the controller. The validity of the proposed method is asserted by the computer simulation.

  • Real-Time Road Sign Detection Using Fuzzy-Boosting

    Changyong YOON  Heejin LEE  Euntai KIM  Mignon PARK  

     
    PAPER-Intelligent Transport System

      Vol:
    E91-A No:11
      Page(s):
    3346-3355

    This paper describes a vision-based and real-time system for detecting road signs from within a moving vehicle. The system architecture which is proposed in this paper consists of two parts, the learning and the detection part of road sign images. The proposed system has the standard architecture with adaboost algorithm. Adaboost is a popular algorithm which used to detect an object in real time. To improve the detection rate of adaboost algorithm, this paper proposes a new combination method of classifiers in every stage. In the case of detecting road signs in real environment, it can be ambiguous to decide to which class input images belong. To overcome this problem, we propose a method that applies fuzzy measure and fuzzy integral which use the importance and the evaluated values of classifiers within one stage. It is called fuzzy-boosting in this paper. Also, to improve the speed of a road sign detection algorithm using adaboost at the detection step, we propose a method which chooses several candidates by using MC generator. In this paper, as the sub-windows of chosen candidates pass classifiers which are made from fuzzy-boosting, we decide whether a road sign is detected or not. Using experiment result, we analyze and compare the detection speed and the classification error rate of the proposed algorithm applied to various environment and condition.

  • T-S Fuzzy Model-Based Synchronization of Time-Delay Chaotic System with Input Saturation

    Jae-Hun KIM  Hyunseok SHIN  Euntai KIM  Mignon PARK  

     
    PAPER-Systems and Control

      Vol:
    E87-A No:12
      Page(s):
    3372-3380

    This paper presents a fuzzy model-based approach for synchronization of time-delay chaotic system with input saturation. Time-delay chaotic drive and response system is respectively represented by Takagi-Sugeno (T-S) fuzzy model. Specially, the response system contains input saturation. Using the unidirectional linear error feedback and the parallel distributed compensation (PDC) scheme, we design fuzzy chaotic synchronization system and analyze local stability for synchronization error dynamics. Since time-delay in the transmission channel always exists, we also take it into consideration. The sufficient condition for the local stability of the fuzzy synchronization system with input saturation and channel time-delay is derived by applying Lyapunov-Krasovskii theory and solving linear matrix inequalities (LMI's) problem. Numerical examples are given to demonstrate the validity of the proposed approach.

  • A State Observer for a Special Class of MIMO Nonlinear Systems and Its Application to Induction Motor

    Sungryul LEE  Euntai KIM  Mignon PARK  

     
    PAPER-Systems and Control

      Vol:
    E86-A No:4
      Page(s):
    866-873

    This paper presents an observer design methodology for a special class of MIMO nonlinear systems. First, we characterize the class of MIMO nonlinear systems that consists of the linear observable part and the nonlinear part with a block triangular structure. Also, the similarity transformation that plays an important role in proving the convergence of the proposed observer is generalized to MIMO systems. Since the gain of the proposed observer minimizes a nonlinear part of the system to suppress for the stability of the error dynamics, it improves the transient performance of the high gain observer. Moreover, by using the generalized similarity transformation, it is shown that under some observability and boundedness conditions, the proposed observer guarantees the global exponential convergence to zero of the estimation error. Finally, the simulation results for induction motor are included to illustrate the validity of our design scheme.

  • Queueing Analysis for ATM switching of Mixed Traffic with Priority

    Cheul SHIM  JungGyu KIM  Mignon PARK  SangBae LEE  

     
    LETTER-Communication Theory

      Vol:
    E74-A No:10
      Page(s):
    3086-3091

    This paper proposes an analysis method of a priority scheme for mixed Continuous-Bit-Rate (CBR) and burst traffic contending based on Asynchronous Transfer Mode (ATM) which applied the future B-ISDN. The method is analyzed througn two separated source models; binary source model for burst traffic and random source model for CBR traffic. First we defines arrival process using the two source models according to traffic characteristics so that in adaptation to queueing modeling the system is analyzed through M/G/1/N. Next in view point of service process three priority schemes: push-out scheme, partial buffer sharing and separate route for each traffic loss are proposed. Here we impose two different priority classes on each source model. With the use of superposition of traffic from a number of independent random sources and binary sources, the partial buffer sharing scheme is proved to be best in three priority schemes for addmissible load and cell loss probability. In this paper, we propose partial buffer sharing scheme with priority scheme for two different traffics.

  • Output Feedback Tracking Control Using a Fuzzy Disturbance Observer

    Euntai KIM  Mignon PARK  

     
    LETTER-Systems and Control

      Vol:
    E86-A No:10
      Page(s):
    2693-2699

    In this letter, a new output feedback tracking control using a fuzzy disturbance observer (FDO) is proposed and its application to control of a nonlinear system in the presence of the internal parameter perturbation and external disturbance is presented. An FDO using a filtered signal is developed and the high gain observer (HGO) is employed to implement the output feedback tracking control. It is shown in a rigorous manner that all the errors involved can be kept arbitrarily small. Finally, the effectiveness and the feasibility of the suggested method is demonstrated by computer simulation.

  • Human Face Detection via Characterized Convex Regional Relationship in Color Images

    Chang-Woo PARK  Euntai KIM  Mignon PARK  

     
    LETTER-Image Processing, Image Pattern Recognition

      Vol:
    E86-D No:4
      Page(s):
    759-762

    In this letter, we propose a new method to detect faces in color images based on the characterized convex regional relationship. We detect skin and hair likeness regions using the derived skin and hair color models and the convex skin likeness and hair likeness regions are adopted as the characteristic convex regions. Finally, human faces can be detected via their intersection relationship. The proposed algorithm can accomplish face detection in an image including not only single face but also multi-faces and also detect deformed faces efficiently. To validity the effectiveness of the proposed method, we make experiments with various cases.

  • The State Feedback Control Based on Fuzzy Observer for T-S Fuzzy Systems with Unknown Time-Delay

    Hyunseok SHIN  Euntai KIM  Mignon PARK  

     
    PAPER-Systems and Control

      Vol:
    E86-A No:9
      Page(s):
    2333-2339

    In this paper, we present an output feedback controller using a fuzzy controller and observer for nonlinear systems with unknown time-delay. Recently, Cao et al. proposed a stabilization method for the nonlinear time-delay systems using a fuzzy controller when the time-delay is known. In general, however, it is impossible to know or measure this time-varying delay. The proposed method requires only the upper bound of the derivative of the time-delay. We represent the nonlinear system with the unknown time-delay by Takagi-Sugeno (T-S) fuzzy model and design the fuzzy controller and observer for the systems using the parallel distributed compensation (PDC) scheme. In addition, we derive the sufficient condition for the asymptotic stability of the equilibrium point by applying Lyapunov-Krasovskii theorem to the closed-loop system and solve the condition in the formulation of LMI. Finally, computer simulations are included to demonstrate the effectiveness of the suggested method.

  • Adaptive Control of Uncertain Chaotic Systems Based on Takagi-Sugeno Fuzzy Models

    Chang-Woo PARK  Chang-Hoon LEE  Jung-Hwan KIM  Mignon PARK  

     
    PAPER-Chaos & Dynamics

      Vol:
    E84-A No:9
      Page(s):
    2101-2117

    In this paper, in order to control uncertain chaotic system, an adaptive fuzzy control (AFC) scheme is developed for the multi-input/multi-output plants represented by the Takagi-Sugeno (T-S) fuzzy models. The proposed AFC scheme provides robust tracking of a desired signal for the T-S fuzzy systems with uncertain parameters. The developed control law and adaptive law guarantee the boundedness of all signals in the closed-loop system. In addition, the chaotic state tracks the state of the stable reference model (SRM) asymptotically with time for any bounded reference input signal. The suggested AFC design technique is applied to control of a uncertain Lorenz system based on T-S fuzzy model such as stabilization, synchronization and chaotic model following control (CMFC).