• Title/Summary/Keyword: second-order system

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Stabilization of Multilocomotive Powered Train System Using Lyapunov Functions (Lyapunov 함수에 의한 대규모 열차 시스템의 안정화)

  • Nam, Boo-Hee
    • Journal of Industrial Technology
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    • v.11
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    • pp.33-41
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    • 1991
  • Using the Brayton and Tong's computer-generated Lyapunov functions, we stabilize the multilocomotive train system so that the system is globally asymptotically stable. We decompose an interconnected system into the second order subsystems. Lyapunov functions of the free subystems are constructed using the Brayton and Tong's algorithm. An aggregated test matrix is determined in terms of the qualitative properties of the free subsystems and the interconnecting structures. Stated feedback is used for stabilizing the entire system.

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Adaptive Identification of a Time-varying Volterra system using the FWLS (filtered weighted least squares) Algorithm (FWLS 적응 알고리듬을 이용한 시변 볼테라 시스템 식별)

  • Ahn, K.Y.;Jeong, I.S.;Nam, S.W.
    • Proceedings of the KIEE Conference
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    • 2004.05a
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    • pp.3-6
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    • 2004
  • In this paper, the problem of identifying a time-varying nonlinear system in an adaptive way was considered, whereby the time-varying second-order Volterra series was employed to model the system and the filtered weighted least squares (FWLS) algorithm was utilized for the fast parameter tracking capability with low computational burden. Finally, the performance of the proposed approach was demonstrated by providing some computer simulation results.

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Change of International Political Order s and International Aviation Orders - From the viewpoint of International Aviation Law and R.O.K- U.S Air Service Agreement - (국제정치와 국제항공의 질서의 변화 - 국제항공법과 한미항공협정을 중심으로 -)

  • Lee, Jong-Sik
    • The Korean Journal of Air & Space Law and Policy
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    • v.20 no.1
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    • pp.109-142
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    • 2005
  • This paper aims to study international political orders and aviational orders since the second World War, to investigate the influences between the two orders, to connect them with the air transportation service agreement between Korea and USA, and to prospect international aviation orders in the future. The first international aviation order after the second World War is built up by international public goods under hegemonic stability theory in the realistic international order. Second order is a kind of cooperation system through the international institutions under the neo-liberalistic international order from the late of 1970s. Third order is the multiple cooperation through the shared epistemology, understanding, and knowledge under the international social constructivism from the 1990s. This paper prospects that international aviation order in the future will be developed through the multiple channels for the civilian users' conveniences and the openness for the users.

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A Study on Evaluation of the Priority Order about Framework Data Building (기본지리정보 구축 우선순위 평가에 관한 연구)

  • 김건수;최윤수;조성길;이상미
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • 2004.11a
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    • pp.361-366
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    • 2004
  • Geographic Information has been used widely for landuse and management, city plan, and environment and disaster management, etc., But geographic information has been built for individual cases using various methods. Therefore, the discordancy in data, double investment, confusion of use and difficulty of decision supporting system have been occurred. In order to solve these problems, national government is need to framework database. This framework database was enacted for building and use of National Geographic Information System and focused on basic plan of the second national geographic information system. Also, the framework database was selected of eight fields by NGIS laws and 19 detailed items through meeting of framework committee since 2002. In this research, The 19 detailed items( road, railroad, coastline, surveying control point etc.,) of framework database consider a Priority order, In the result of this research, the framework database is obtain to a priority order for building and the national government will carry effectively out a budget for the framework database building. Each of 19 detailed items is grouping into using the priority order of the framework database by AHP analysis method and verified items by decision tree analysis method. The one of the highest priority order items is a road, which is important for building, continuous renovation, and maintain management for use.

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Importance Sampling Technique for System Reliability Analysis of Bridge Structures (교량구조의 체계 신뢰성 해석을 위한 중요도 표본추출 기법)

  • 조효남;김인섭
    • Computational Structural Engineering
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    • v.4 no.2
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    • pp.119-129
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    • 1991
  • This study is directed for the development of an efficient Importance Sampling Technique for system reliability analysis of bridge structures. Many methods have been proposed for structural reliability assessment such as the First-order Second-Moment Method, the Advanced Second-Moment Method, Monte Carlo Simulation, etc. The Importance Sampling Technique can be employed to obtain accurate estimates for the system reliability with reasonable computation effort. Based on the results of example analysis, it may be concluded that Importance Sampling Technique is a very effective tool for the system reliability analysis.

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Parametric Modelling of Uncoupled System (언커플시스템의 파라메트릭 모델링)

  • Yoon, Moon-Chul;Kim, Jong-Do;Kim, Kwang-Heui
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.5 no.3
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    • pp.36-42
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    • 2006
  • The analytical realization of uncoupled system was introduced in this study using times series and its spectrum analysis. The ARMAX spectra of time series methods were compared with the conventional FFT spectrum. Also, the response of second order system uncoupled was solved using the Runge-Kutta Gill method. In this numerical analysis, the displacement, velocity and acceleration were calculated. The displacement response among them was used for the power spectrum analysis. The ARMAX algorithm in time series was proved to be appropriate for the mode estimation and spectrum analysis. Using the separate response of first and second mode, each modes were calculated separately and the response of mixed modes was also analyzed for the mode estimation using several time series methods.

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Synchronous Control of a Two-Axes Driving System by Disturbance Observer and PID Controller (외란 관측기와 PID제어기를 이용한 2축 주행시스템의 동기제어)

  • 변정환;김영복;양주호
    • Journal of Ocean Engineering and Technology
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    • v.15 no.1
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    • pp.67-72
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    • 2001
  • In this study, a methodology of synchronous control which can be applied to position synchronization of a two-axes driving system has been developed. The synchronous error is caused by model uncertainties and torque disturbance of each axis. To overcome these problems, the proposed synchronous control system has been composed of two speed controllers, disturbance observers, and one synchronous controller. The speed controllers, based on the PID control law are aimed at the following to speed reference. And the parameters of speed controllers have been designed in order for the speed response fo the second axis to correspond with the one of the first axis. The disturbance observer has been designed to restrain the torque disturbance. The synchronous controller eliminates the synchronous error by controlling the speed of the second axis. The effectiveness of the proposed method has been verified through simulation.

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Study on the Corrosionproofing in Concrete by Cathodic Protection (전위변화에 의한 콘크리트내의 철근방식에 관한 연구)

  • Lim, Seo-Hyung
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.3 no.2
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    • pp.213-220
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    • 1999
  • The purpose of this study is to apply cathodic protection to reinforced concrete structure and provide fundamental data to prevent the corrosion. The theory of cathodic protection of steel in concrete is to apply sufficient direct current so that corroding anodes on the steel are prevented from discharging ions. Two methods are used to supply the external current. In one, the protected metal is the cathode by connecting it to a more active metal. In the second, an external direct current power source supplies the current. The first is the sacrificial-anode system and the second the impressed-current system. The study results showed that the corrosion of the reinforcing steel in concrete could be enormously decreased by using protective current. The sacrificial anode and concrete nave to be adhered closely each in order to prevent the corrosion of reinforcing steel.

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FINITE ELEMENT APPROXIMATION OF THE DISCRETE FIRST-ORDER SYSTEM LEAST SQUARES FOR ELLIPTIC PROBLEMS

  • SHIN, Byeong-Chun
    • Communications of the Korean Mathematical Society
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    • v.20 no.3
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    • pp.563-578
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    • 2005
  • In [Z. Cai and B. C. Shin, SIAM J. Numer. Anal. 40 (2002), 307-318], we developed the discrete first-order system least squares method for the second-order elliptic boundary value problem by directly approximating $H(div){\cap}H(curl)-type$ space based on the Helmholtz decomposition. Under general assumptions, error estimates were established in the $L^2\;and\;H^1$ norms for the vector and scalar variables, respectively. Such error estimates are optimal with respect to the required regularity of the solution. In this paper, we study solution methods for solving the system of linear equations arising from the discretization of variational formulation which possesses discrete biharmonic term and focus on numerical results including the performances of multigrid preconditioners and the finite element accuracy.

A Low-Order Controller Design of Active Pantograph System (능동판토그래프의 저차제어기 설계)

  • Baek, Seung-Koo;Chang, Seok-Gahk;Kwon, Sung-Tae;Kim, Jin-Hwan
    • Proceedings of the KSR Conference
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    • 2009.05a
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    • pp.940-945
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    • 2009
  • This paper presents the design method of low order controller for the active pantograph of electric train system. The pantograph is the most playa role to supply constant current to the train. The design objectives are to have good tracking performance about reference contact force despite the stiffness variation that is like sinusoidal function concerned in train speed or span length of contact wire. In this paper, we consider stiffness variation from external disturbance of active pantograph to simplify model equation, and propose simple second-order controller which is designed by Characteristic ratio assignment(CRA) control method. Finally, we verify time response appling to model equation of real system and frequency response about parameter uncertainty like stiffness variation. it is performed by Matlab version 6.5 and Matlab simulink simulation.

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