• Title/Summary/Keyword: Lee Sam

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A Hydroelastic Response Analysis of a Very Large Floating Structure of Barge-Type in Waves (바아지식 초대형 부유 구조물의 유탄성 응답 해석)

  • Gu, Ja-Sam;Jo, Hyo-Je;Kim, Byeong-Hyeon;Lee, Chang-Ho
    • Journal of Ocean Engineering and Technology
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    • v.12 no.2 s.28
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    • pp.43-56
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    • 1998
  • A barge-type structure has been recently watched since The Floating Structures Association of Japan proposed the new concept as the most suitable one of floating airports. In this paper, the method, which is based on a combination of a three-dimensional source distribution method and the wave interaction theory is applied to very large floating structure of barge-type. The calculated results show good agreement with the experimental and calculated ones by Yago and remarkable characteristics concerning the hydroelastic behavior of the very large floating structure on the effects of hydrodynamic interactions and choice of body modelling.

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A study on Ad hoc network path of optimized by using context awareness (속성정보를 이용한 최적의 자율망 경로탐색 기법에 관한 연구)

  • Chi, Sam-Hyun;Lee, Kang-Whan
    • Proceedings of the IEEK Conference
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    • 2008.06a
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    • pp.765-766
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    • 2008
  • In this paper, It has been emphasized of important path access during transmit of node when each node transmit broadcast service which one's of new MANET (Mobile Ad hoc Networks) of autonomy and mobility network structures. It has proposed analysis methods are hierarchical path structure of transmit which experience context aware through confidence to network connectivity alone as issue which can be reduce duplicate of beam forming on networks and maintenance one's of method got to optimized of transmission network that status information of context awareness using ad hoc ODDMRP(Ontology Doppler effect Dynamic Multicast Routing Protocol) path method.

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Development of Ultrasonic Test Equipment for Investigating the Morphology of Barrier Materials

  • Kim Sung-Ho;Lee Young-Sam
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.6 no.3
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    • pp.217-222
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    • 2006
  • Recently, LG chemical corporation developed new material called HYPERIER, which has an excellent barrier characteristic. It has many layers which are made of nano-composite within LDPE(Low-Density Poly Ethylene). In order to guarantee the quality of the final product from the production line, a certain test equipment is required to investigate the existence of layers inside the HYPERIER. In this work, ultrasonic sensor based test equipment for investigating the existence of inner layers is proposed. However, it is a tedious job for human operators to check the existence by just looking at the resounding waveform from ultrasonic sensor. Therefore, to enhance the performance of the ultrasonic test equipment, wavelet and PCA(Principle Componet Analysis) schemes are introduced into neural network scheme which is used for classification. To verify the feasibility of the proposed scheme, some experiments are executed.

Performance Analysis of the Centrifugal Pump Impeller Using Commercial CFD Code (상용 CFD코드를 이용한 원심펌프 임펠러의 성능해석)

  • Choi, Young-Seok;Lee, Yong-Kab;Hong, Soon-Sam;Kang, Shin-Hyung
    • 유체기계공업학회:학술대회논문집
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    • 2000.12a
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    • pp.305-311
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    • 2000
  • A commercial CFD code is used to compute the 3-D viscous flow field within the impeller o( a centrifugal pump. Several preliminary numerical calculations are carried out to determine the influence of the parameters such as the grid systems, the numerical schemes, the turbulence models and the shape of the vaneless diffusers at the design flow rate. The results of the preliminary study are used for the calculation of the off-design flow conditions. The circumferentially averaged results such as the radial and tangential velocities, the exit flow angle, the slip factor, the static pressure and the total pressure are compared with the experimental data at the impeller exit to discuss the influence of the prescribed parameters.

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A State Space Analysis on the Stability of Periodic Orbit Predicted by Harmonic Balance

  • Sung, Sang-Kyung;Lee, Jang-Gyu;Kang, Tae-Sam
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.67.5-67
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    • 2001
  • A closed loop system with a linear plant and nonlinearity in the feedback connection is analyzed for its quasi-static orbital stability by a state-space approach. First a periodic orbit is assumed to exist in the loop which is determined by describing function method for the given nonlinearity. This is possible by selecting a proper nonlinearity and a rigorous justification of the describing function method.[1-3, 18, 20]. Then by introducing residual operator, a linear perturbed model can be formulated. Using various transformations like a modified eigenstructure decomposition, periodic-averaging, charge of variables and coordinate transformation, the stability of the periodic orbit, as a solution of harmonic balance, can be shown by investigating a simple scalar function and result of linear algebra. This is ...

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A Constrained Receding Horizon Estimator with FIR Structures

  • Kim, Pyung-Soo;Lee, Young-Sam
    • Transactions on Control, Automation and Systems Engineering
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    • v.3 no.4
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    • pp.289-292
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    • 2001
  • This paper concerns with a receding horizon estimator (RHE) for discrete-time linear systems subject to constraints on the estimate. In solving the optimization for every horizons, the past all measurement data outside the horizon is discarded and thus the arrival cost is not considered. The RHE in the current work is a finite impulse response (FIR) structure which has some good inherent properties. The proposed RHE can be represented in the simple matrix form for the unconstrained case. Various numerical examples demonstrate how including constraints in the RHE can improve estimation performance. Especially, in the application to the unknown input estimation, it will be shown how the FIR structure in the RHE can improve the estimation speed.

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Design of a new command to line-of-sight guidance law via feedback linearization technique (궤환 선형화 기법을 응용한 새로운 시선 지령 유도 법칙의 개발)

  • Chong, Song;ha, In-Joong;Hur, Jong-Sung;Ko, Myoung-Sam;Song, Taek-Lyul;Ahn, Jo-Young;Lee, Jang-Gyu
    • 제어로봇시스템학회:학술대회논문집
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    • 1989.10a
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    • pp.93-98
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    • 1989
  • This paper describes the application of the recently developed feedback linearization technique to designing a new Command to Line-of-Sight (CLOS) guidance law. We show that the CLOS guidance problem can be formulated as a tracking problem. Then, using the feedback input-output linearization technique, we find a new 3dimensional CLOS guidance law that can assure zero miss distance for a randomly maneuvering target. It sheds light on the feedforward acceleration compensation terms used in the conventional CLOS guidance laws to improve the performance. To illustrate further the significance of our result, simulation results are given.

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A modelling methodology for robotic workcells through knowledge base

  • Kim, Dae-Won;Ko, Myoung-Sam;Lee, Bum-Hee
    • 제어로봇시스템학회:학술대회논문집
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    • 1989.10a
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    • pp.583-588
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    • 1989
  • In this paper, a modelling methodology for a robotic workcell is proposed and compared with the conventional Petri nets model. Also, a method for managing the cell operation is described through the knowledge base. The knowledge bases for state transition and assembly job information are obtained from the state transition map(STM) and the assembly job tree(AJT), respectively. Using the knowledge base, the system structure is discussed in both managing the cell operation and evaluating the various performance. Finally, a simulation algorithm is presented with the simulation results to show the effectiveness of the proposed modelling approach.

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Path Planning and Obstacle Avoidance Algorithm of an Autonomous Traveling Robot Using the RRT and the SPP Path Smoothing (RRT와 SPP 경로 평활화를 이용한 자동주행 로봇의 경로 계획 및 장애물 회피 알고리즘)

  • Park, Yeong-Sang;Lee, Young-Sam
    • Journal of Institute of Control, Robotics and Systems
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    • v.22 no.3
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    • pp.217-225
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    • 2016
  • In this paper, we propose an improved path planning method and obstacle avoidance algorithm for two-wheel mobile robots, which can be effectively applied in an environment where obstacles can be represented by circles. Firstly, we briefly introduce the rapidly exploring random tree (RRT) and single polar polynomial (SPP) algorithm. Secondly, we present additional two methods for applying our proposed method. Thirdly, we propose a global path planning, smoothing and obstacle avoidance method that combines the RRT and SPP algorithms. Finally, we present a simulation using our proposed method and check the feasibility. This shows that proposed method is better than existing methods in terms of the optimality of the trajectory and the satisfaction of the kinematic constraints.

Development of a DMC Block for Use with an RCP System and its Application (RCP 시스템에서 사용가능한 DMC (Dynamic Matrix Control) 블록의 개발과 응용)

  • Lee, Young-Sam;Yu, Kwang-Myung
    • Journal of Institute of Control, Robotics and Systems
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    • v.21 no.9
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    • pp.827-835
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    • 2015
  • In this paper, we present the implementation method of Dynamic Matrix Control(DMC) block for use with a Rapid Control Prototyping(RCP) system and consider the speed control of a DC motor using the developed DMC block. Firstly, we briefly introduce a lab-built RCP system. Secondly, we present a method for implementing a DMC block using C-language, which enables the DMC algorithm to be represented in a library block that can be used in a Simulink environment. Finally, we use the developed DMC block for the speed control of a DC motor, through which we show that the DMC-based control system can be easily implemented and applied to the real-time control of systems with relatively fast dynamics.