• 제목/요약/키워드: Time Simulation.

검색결과 16,004건 처리시간 0.041초

실시간 Co-Simulation을 위한 FMI 기반 시간관리 기법 (An FMI-based Time Management Scheme for Real-time Co-Simulation)

  • 경동구;조인휘;김원태
    • 전기전자학회논문지
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    • 제24권2호
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    • pp.426-434
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    • 2020
  • CPS의 대규모 시뮬레이션을 연동하기 위한 표준으로 FMI가 연구되고 있다. FMI를 이용한 대규모 시뮬레이션에서 결과의 신뢰성을 보장하기 위해 시간관리 기법을 통한 이벤트 처리가 필요하다. 본 논문은 CPS와 같은 대규모 Co-Simulation 환경에서 실시간성과 정확성을 보장하도록 한다. 실시간성을 보장하기 위해 Wallclock time과 Simulation time을 동기화한다. 또한 정확성을 보장하기 위해 시뮬레이션을 진행하기 전에 이벤트 여부를 확인한 후, 이벤트 발생시간까지 실시간성을 유지하면서 최대한 작은 step size로 시뮬레이션을 진행한다. 그 결과 Co-Simulation 환경에서 발생하는 이벤트를 순차적으로 즉시 처리하였으며, 실시간성을 보장함과 동시에 시뮬레이션 해상도를 최대로 하여 수치적분 에러를 최소화한다. 실험에서 제안하는 기법은 이벤트 처리가 즉시 이루어졌으며, 해상도를 보장하지 않는 기존의 시간관리 기법과 달리 수치적분 에러가 1/5가량 감소하는 것을 확인하였다.

DEVS 모델의 낙관적 분산 시뮬레이션을 위한 사건 정렬 방법 (Events Ordering in Optimistic Distributed Simulation of DEVS Models)

  • 김기형
    • 한국시뮬레이션학회논문지
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    • 제5권1호
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    • pp.81-90
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    • 1996
  • In this paper, we propose a new events ordering mechanism for the optimistic distributed simulation of DEVS models. To simulate DEVS models in a distributed environment, a synchronization protocol is required for correct simulation. Time Warp is the most well-known optimistic synchronization protocol for distributed simulation. However, employing the Time Warp protocol in distributed simulation of DEVS models incurs events ordering problem due to the semantic difference between Time Warp and DEVS, Thus, to resolve such semantic difference, we devise the time-and-priority-stamp and $\varepsilon$ -delay schemes. The proposed schemes can order simultaneous events correctly in Time Warp-based distributed simulation of DEVS models.Time Warp and DEVS, Thus, to resolve such semantic difference, we devise the time-and-priority-stamp and $\varepsilon$ -delay schemes. The proposed schemes can order simultaneous events correctly in Time Warp-based distributed simulation of DEVS models.

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Multiprocessor를 이용한 연속 동특성계의 실시간 시뮬레이션에 관한 연구 (A Study on the Real Time Simulation of Continuous Dynamic System Using a Multiprocessor)

  • 곽병철;양해원
    • 대한전자공학회논문지
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    • 제24권4호
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    • pp.559-567
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    • 1987
  • In this paper, the real time simulation of continuous dynamic system was performed by general integration algorithms using multiprocessor. For the stable simulation, the relation between stability of integration method and integration step-size was investigated from the stability graph. As a typical illustration, the real-time digital simulation and the real-time hard-ware-in-the-loop simulation of flight control system were performed and reviewed. Moreover through the real-time simulation, the design verification and performace test of flight control system could be evaluated. The computer used for simulation is AD10, which is a very high-speed special-purpose computer designed specifically for a time-critical simulation of large and complex models of dynamic systems. The simulation validity is demonstrated by comparing hardware simulation results with software simulation results.

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실시간 응용시 Mini MAP의 시뮬레이션에 의한 성능해석에 관한 연구 (Performance analysis of mini MAP architecture in real time application by simulation method)

  • 김덕우;정범진;권욱현
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1987년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 16-17 Oct. 1987
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    • pp.382-388
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    • 1987
  • In this paper, the performance of Mini MAP architecture is analyzed by simulation method. Token rotation time and waiting time are obtained by simulation. The results of the simulation are compared with these of the analytic model. From these comparisons, it is shown that simulation results are approximately identical to analytic results. Mini MAP architecture has good real time performances in token rotation time and waiting time and can be used to many real time applications.

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REAL-TIME SIMULATION OF A HIGH SPEED MULTIBODY TRACKED VEHICLE

  • YI K. S.;YI S.-J.
    • International Journal of Automotive Technology
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    • 제6권4호
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    • pp.351-357
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    • 2005
  • Development of a real-time simulation model for high-speed and multibody tracked vehicles is difficult because they involve hundreds of highly nonlinear equations. In the development of a reliable tracked vehicle model for real-time simulation, it is helpful to use an off-line tracked vehicle model developed by considering all the degrees of freedom of each element. This paper presents a step-by-step procedure for the development of a real-time simulation model based on the off-line tracked vehicle model. The road input data, Profile IV, is used for the real time simulation and simulation results are compared with vehicle test results obtained in the military test field. It is noted that the simulation results are quite close to the test results.

분산 전문가 시스템의 기능을 갖는 이산사건 시뮬레이션: 제조 공정 오류 감지와 진단에의 적용 (Discrete Event Simulation with Embedded Distributed Expert System: Application to Manufacturing Process Monitoring and Diagnosis)

  • 조대호
    • 한국시뮬레이션학회논문지
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    • 제7권2호
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    • pp.137-152
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    • 1998
  • One of the components that constitute the simulation models is the state variables whose values are determined by the time related simulation process. Embedding rule-based expert systems into the simulation models should provide a systematic way of handling these time-dependent variables without distracting the essential problem solving capabilities of the expert systems which are well suited for expressing the decision making function of complex cases. The expert system, however, is inefficient in dealing with the time elapsing characteristics of target system compare to the simulation models. To solve the problem, this paper provides an interruptible inference engine whose inferencing process can be interrupted when the variables' value, which are used as the parameters of the rules, are not yet determined due to the time dependent nature of the state variables. The process is resumed when the variables are ready. The elapse of time is calculated by time-advance function of the simulation model to which the expert system has been embedded. The example modeling shown exploits the embedded interruptible inferencing capability for the controlling and monitoring of metal grating process.

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DEVS형식론을 적응한 HLA기반의 분산 실시간 시뮬레이션 시스템 개발 (Development of the Distributed Real-time Simulation System Based on HLA and DEVS)

  • 김호정;이재현;조길석
    • 한국군사과학기술학회지
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    • 제9권3호
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    • pp.25-32
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    • 2006
  • Weapon systems composed of several subsystems execute various engagement missions in distributed combat environments in cooperation with a large number of subordinate/adjacent weapon systems as well as higher echelons through tactical data links. Such distributed weapon systems require distributed real-time simulation test beds to integrate and test their operational software, analyze their performance and effects of cooperated engagement, and validate their requirement specifications. These demands present significant challenges in terms of real-time constraints, time synchronization, complexity and development cost of an engagement simulation test bed, thus necessitate the use of high-performance distributed real-time simulation architectures, and modeling and simulation techniques. In this paper, in order to meet these demands, we presented a distributed real-time simulation system based on High Level Architecture(HLA) and Discrete Event System Specification(DEVS). We validated its performance by using it as a test bed for developing the Engagement Control System(ECS) of a surface-to-air missile system. The proposed technique can be employed to design a prototype or model of engagement-level distributed real-time simulation systems.

SED2D모형을 이용한 저수지 퇴사거동 모의-모의시간간격의 민감도를 중심으로 (Simulation of Sediment Deposition Behavior in a Reservoir using a SED2D model: Focusing on Sensitivity of Simulation Time Step)

  • 김대근
    • 상하수도학회지
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    • 제26권1호
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    • pp.87-95
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    • 2012
  • In this study, the following conclusions were obtained from an investigation of the effect of the simulation time step on the simulation results of the two-dimensional, vertically averaged sediment transport model SED2D and an analysis of the deposited sediment distribution in suspended sediments of reservoirs according to grain size. The simulation time step has a significant effect on the deposited sediment distribution in a reservoir. In particular, if the simulation time step is set to be excessively large, physically invalid results are obtained. Additionally, in order to determine an appropriate simulation time step for SED2D, the selection of a simulation time step that will allow the analysis of the suspended sediment concentration profile at the main points of the simulation domain is necessary. The deposited sediment distribution in a reservoir according to grain size, including suspended sediments of clay, silt, and sand, was successfully simulated. Such information will prove valuable in application to the establishment of efficient management and reduction measures of reservoir sediment deposits.

Framework for Component-based Modeling/Simulation of Discrete Event Systems

  • Cho, Young-Ik;Kim, Jae-Hyun;Kim, Tag-Gon
    • 한국시뮬레이션학회:학술대회논문집
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    • 한국시뮬레이션학회 2001년도 The Seoul International Simulation Conference
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    • pp.484-484
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    • 2001
  • The sophistication of current software applications results in the increasing cost fur software development time. The component-based software development framework is proposed to overcome the difficulty and time-consuming requirements by modularity and reusability. As is the general software case, a component-based simulation framework encourages the reusability of the real system model based on the modularity of the applied simulation methodology. This paper presents a component-based simulation environment that is based on the DEVS/COM run-time infrastructure. The DEVS (Discrete Event System Specification) formalism provides a formal modeling and simulation framework for the generic dynamic systems [1] and Microsoft's COM (Component Object Model) is one of the strongest competitor fur the component standard. The reusability by the DEVS/COM simulation environment saves model development time remarkably and component technology make simulator itself to be a subparts of real application.

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분산 시뮬레이션을 위한 효율적인 보수적 알고리즘 개발 (Development of Efficient Conservative Algorithm for Distributed Simulation)

  • 이영해
    • 한국시뮬레이션학회논문지
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    • 제8권1호
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    • pp.77-88
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    • 1999
  • There are two approaches to handle the Causality Error in parallel and distributed simulation. One approach is based on the conservative time synchronization and the other is the optimistic time synchronization. In this paper an efficient null message reduction method for the conservative time synchronization approach is suggested with the experimental results, which could improve performance of simulation and avoid deadlock situations.

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