• 제목/요약/키워드: Discrete Model

검색결과 2,032건 처리시간 0.026초

DEVCS 모델을 사용한 심근 활성화과정의 시뮬레이션 (A Simulation of the Myocardium Activation Process using the Discrete Event Cell Space Model)

  • 김광년;정동근;김기련;최병철;이정태;전계록
    • 한국시뮬레이션학회논문지
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    • 제13권4호
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    • pp.1-16
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    • 2004
  • The modelling and simulation of the activation process for the heart system is meaningful to understand special excitatory and conductive system in the heart and to study cardiac functions because the heart activation conducts through this system. This thesis proposes two dimensional cellular automaton(CA) model for the activation process of the myocardium and conducted simulation by means of discrete time and discrete event algorithm. In the model, cells are classified into anatomically similar characteristic parts of the heart and each of cells has a set of cells with preassigned properties. Each cell in this model has state variables to represent the state of the cell and has some state transition rules to change values of state variables executed by state transition function. The state transition rule is simple as follows. First, the myocardium cell at rest stay in passive state. Second, if any one of neighborhood cell in the myocardium cell is active state then the state is change from passive to active state. Third, if cell's state is an active then automatically go to the refractory state after activation phase. Four, if cell's state is refractory then automatically go to the passive state after refractory phase. These state transition is processed repeatedly in all cells through the termination of simulation.

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OSCILLATION AND ATTRACTIVITY OF DISCRETE NONLINEAR DELAY POPULATION MODEL

  • Saker, S.H.
    • Journal of applied mathematics & informatics
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    • 제25권1_2호
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    • pp.363-374
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    • 2007
  • In this paper, we consider the discrete nonlinear delay model which describe the control of a single population of cells. We establish a sufficient condition for oscillation of all positive solutions about the positive equilibrium point and give a sufficient condition for the global attractivity of the equilibrium point. The oscillation condition guarantees the prevalence of the population about the positive steady sate and the global attractivity condition guarantees the nonexistence of dynamical diseases on the population.

이산사건 시스템 제어 및 모니터링을 위한 퍼지 패트리네트 응용 (Application of fuzzy Petri nets for discrete event system control and monitoring)

  • 노명균;홍상은
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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    • pp.403-406
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    • 1997
  • This paper presents a Petri net approach for the control and monitoring of discrete event system. The proposed model is fuzzy Petri nets based on the fuzzy logic with Petri nets and the hierarchy concept. Fuzzy Petri nets have been used to model the imprecise situations which can arise within automated manufacturing system, and also the hierarchy concept allow to handle the refinement of places and transition in Petri nets model. These will form the foundation of a simulator-tool with manipulation interface for application of fuzzy Petri nets.

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전력계통안정기를 위한 이산-모드 폐루우프 피이드백에 기준한 SM-MF 제어기 설계 : Part2 (Design of Discrete-Mode CLF-based SM-MF Controller for Power System Stabilizer : Part 2)

  • 이상성;박종근
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1997년도 하계학술대회 논문집 D
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    • pp.1165-1167
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    • 1997
  • In this paper, the continuous sliding mode-model following(SM-MF) power system stabilizer(PSS) including closed-loop feedback(CLF) is extended to discrete-time sliding mode-model following(DSM-MF) PSS including CLF.

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제한된 외란하에서의 강인한 이산 시간 모델 추종 적응 제어 (A Robust Discrete-Time Model Reference Adaptive Control in the Presence of Bounded Disturbances)

  • 이호진;함운철;최계근
    • 대한전자공학회논문지
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    • 제25권12호
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    • pp.1618-1624
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    • 1988
  • In this paper, a robust discrete model reference adaptive controller is proposed using a generalized model reference adaptive algorithm for single-input single-output discrete systems. A signal dependent time-varying dead-zone is employed in a generalized adaptive control structure. This adaptive controller is shown to assure the boundedness of the signals of the system even in the presence of bounded external disturbance.

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A Note on Estimation Under Discrete Time Observations in the Simple Stochastic Epidemic Model

  • Oh, Chang-Hyuck
    • Journal of the Korean Statistical Society
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    • 제22권1호
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    • pp.133-138
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    • 1993
  • We consider two estimators of the infection rate in the simple stochastic epidemic model. It is shown that the maximum likelihood estimator of teh infection rate under the discrete time observation does not have the moment of any positive order. Some properties of the Choi-Severo estimator, an approximation to the maximum likelihood estimator, are also investigated.

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공급사슬시뮬레이션을 위한 이산-연속 모델링 방법에 관한 연구 (A Study on Discrete-Continuous Modeling Methodology for Supply Chain Simulation)

  • 김서진;이영해
    • 한국시뮬레이션학회:학술대회논문집
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    • 한국시뮬레이션학회 2000년도 추계학술대회 논문집
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    • pp.142-149
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    • 2000
  • Most of supply chain simulation models have been developed on the basis of discrete-event simulation. Since supply chain systems are neither completely discrete nor continuous, the need of constructing a model with aspects of both discrete-event simulation and continuous is provoked, resulting in a combined discrete-continuous simulation. Continuous simulation concerns the modeling over time of a system by a representation in which the state variables change continuously with respect to time. In this paper, an architecture of combined modeling for supply chain simulation is proposed, which presents the equation of continuous part in supply chain and how these equations are used supply chain simulation models. A simple supply chain model is demonstrated the possibility and the capability of this approach.

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Demand Forecasting with Discrete Choice Model Based on Technological Forecasting

  • 김원준;이정동;김태유
    • 기술경영경제학회:학술대회논문집
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    • 기술경영경제학회 2003년도 제22회 동계학술발표회 논문집
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    • pp.173-190
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    • 2003
  • 수요예측은 국가와 기업의 전략수립과 효율적인 자원활용에 있어서 필수적인 사전기획요소이다. 본 논문은 이산선택모델과 확산모델을 복합적으로 고려하여 다세대 제품의 수요를 예측하였다. 이산선택모델은 정적인 관점에서 소비자들의 제품에 대한 평가를 분석하는 모델이다. 본 논문에서는 이러한 이산선택모델에 수요의 동적인 변화양상을 고려할 수 있는 확산모델을 결합하였다. 실증분석으로서 1999년에서 2005년까지의 세계 DRAM시장 수요를 예측하였다. 또한, DRAM의 가격과 기억용량에 대해 '무어의 법칙' 과 '학습곡선'을 각각 적용한 기술예측을 시도하였으며, 이를 바탕으로 보다 정교한 예측모델을 전개하였다. 제시된 모델은 산업수준의 자료를 이용하였으므로, 이산선택모델을 inversion 하여 분석을 시도하였다. 이를 통해 기존세대의 DRAM 제품에 대한 수요뿐만 아니라, 새로운 세대의 DRAM 제품에 대한 수요를 비교적 정확히 예측할 수 있었다.

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단일 실행의 빠른 근사해 기법과 반복 실행의 최적화 기법을 이용한 이산형 시스템의 시뮬레이션 연구 (Simulation Study of Discrete Event Systems using Fast Approximation Method of Single Run and Optimization Method of Multiple Run)

  • 박경종;이영해
    • 대한산업공학회지
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    • 제32권1호
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    • pp.9-17
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    • 2006
  • This paper deals with a discrete simulation optimization method for designing a complex probabilistic discrete event simulation. The developed algorithm uses the configuration algorithm that can change decision variables and the stopping algorithm that can end simulation in order to satisfy the given objective value during single run. It tries to estimate an auto-regressive model for evaluating correctly the objective function obtained by a small amount of output data. We apply the proposed algorithm to M/M/s model, (s, S) inventory model, and known-function problem. The proposed algorithm can't always guarantee the optimal solution but the method gives an approximate feasible solution in a relatively short time period. We, therefore, show the proposed algorithm can be used as an initial feasible solution of existing optimization methods that need multiple simulation run to search an optimal solution.

Methodology for Discrete Event Modeling/Simulation of Mobile Agent Systems

  • Kim, Jae-Hyun;Kim, Tag-Gon
    • 한국시뮬레이션학회:학술대회논문집
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    • 한국시뮬레이션학회 2001년도 The Seoul International Simulation Conference
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    • pp.453-458
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    • 2001
  • A mobile agent is an autonomous software agent capable of moving from one computer to another while performing its tasks. We view the agent as a discrete event system in the view of its computation and communication. This paper presents a methodology far modeling and simulation of such a mobile agent system as a discrete event system. The methodology is based on the Mobile Discrete Event System Specification (MDEVS) formalism and the associated simulation environment AgentSim which are previously developed by the authors. Within the methodology an atomic model represents dynamics of a mobile agent; a coupled model is modeled as mobile agent servers for representation of structural changes between atomic agents. Being based on the object-oriented environment the modeling methodology exploits inheritance of basic classes AtomicModel and CoupledModel provided by AgentSim.

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