• Title, Summary, Keyword: simulation

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Development of Web Service-based Parallel and Distributed Simulation (웹서비스 기반의 분산 시뮬레이션 프로토타입 개발)

  • Jo, In-Ho;Ju, Jeong-Min;Park, Yang-Seon;Jo, Hyeon-Bo
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • pp.1033-1039
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    • 2005
  • Parallel and distributed simulation is concerned with the efficient execution of large-scale discrete event simulation models on multiprocessors and distributed platforms. After the development of WWW, many efforts in the parallel and distributed simulation have been made for modeling, particularly building simulation languages and creating model libraries that can be assembled and executed over WWW. However, web-based parallel and distributed simulation is restricted by heterogeneous computing environments. Recently, the advent of XML and web services technology has made these efforts enter upon a new phase. Especially, the web services as a distributed information technology have demonstrated powerful capabilities for scalable interoperation of heterogeneous systems. This paper aims to develop and evaluate the parallel and distributed simulation using the web services technology. In particular, a prototype multi-pass simulation framework is implemented using Java-based web services technology. It focuses on the efficiency of multi-pass simulation used for optimization through the distribution of simulation replication to several simulation service providers. The development of parallel and distributed simulation using web services will help solve efficiently large-scale problems and also guarantee interoperability among heterogeneous networked systems.

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

  • 김서진;이영해
    • Proceedings of the Korea Society for Simulation Conference
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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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Hybrid Systems Modeling and Simulation - Part II: Interoperable Simulation Environment (하이브리드 시스템 모델링 및 시뮬레이션 - 제2부: 시뮬레이터 연동 환경)

  • 임성용;김탁곤
    • Journal of the Korea Society for Simulation
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    • v.10 no.3
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    • pp.15-30
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    • 2001
  • Hybrid simulation may employ different types of simulation based on which models in different system types are developed. The simulation requires simulation time synchronization and data exchange between such simulators, which is called simulators interoperation. This paper develops such interoperable simulation environments for modeling and simulation of hybrid systems whose components consist of continuous and discrete event systems. The environments, one for centerized and the other for distribute, support interoperation between a discrete event simulator of DEVSim++ and a continuous simulator of MATLAB. The centerized environment, HDEVSim++, is developed by extending the sxisting DEVSim++ environment; the distributed environment, HDEVSimHLA, is developed using the HLA/RTl library. Verification of both environments is made and performance comparison between the two using a simple example is presented. .

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SIMULATION EFFICIENCY FOR MULTI-PRODUCTION MODEL

  • Kwon, Chi-Myung
    • Proceedings of the Korea Society for Simulation Conference
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    • pp.8-8
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    • 1992
  • Through a simulation experiment, often an experimenter is concerned with estimating the system parameters of the linear model consisting of m design points from the outputs oft the simulation model. To improve the estimation of the system parameters and reliability of these estimators, appropriate simulation techniques have been developed. For the first order linear model, Schruben and Margolin (1978) exploited the random number assignment rules which uses a combination of common random numbers and antithetic streams in a simulation experiment designed to estimate the system parameters when the design matrix of simulation model admits orthogonal blocking into two blocks. Nozari, Arnold and Pegden (1984) developed a method for appliying the method of control variates to the situation of the linear model having multiple design points. This talk deals with a different way of utilizing controls under the correlation induction strategy of Schruben and Margolin's to improve the simulation efficiency, and presents a procedure for obtaining the estimators of the system parameters analytically. Simulation results on a selected simulation model indicate a promising evidence that a proposed method may yield better results than Schruben and Margolin's method.

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Devlopment HLA DEVS-Obj-C Environment for Distributed Simulation (분산 시뮬레이션을 위한 HLA DEVS-Obj-C 환경 구축)

  • 최두진;조대호
    • Proceedings of the Korea Society for Simulation Conference
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    • pp.85-89
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    • 2002
  • Development of distributed simulation environment must be required in order to simulate the distributed models regionally and inter-operate with running simulations individually, Simulation based on DEVS formalism is difficult to simulate the distributed models. DEVS formalism is modeling methodology. To specify model, this formalism separates behavior and structure, therefore it is able to design complex model easily. HLA is standard framework of distribute simulation environment, It is defined to facilitate the interoperability and the reusability. RTI (Run Time Infrastructure) is software that provides common service to simulation systems and implementation of the HLA Interface Specification. Method of implementation is that modules cooperating with RTI are added to simulator on DEVS simulation environment. On the DEVS simulation environment (DEVS-Obj -C) that already developed, Highest class of abstract simulator uses service that RTI provide, then This environment is able to change DEVS model into Federate and run distribute simulation that inter-operates with the RTI. Because this distributed simulation environment includes convenience of modeling that obtains through the DEVS formalism and accompanies HLA standard, this environment make it possible to simulate with_ complex systems and heterogeneous simulations

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Reverse-Simulation 기법에 의한 다수 평가 함수를 가진 시스템의 최적화

  • 박경종
    • Proceedings of the Korea Society for Simulation Conference
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    • pp.3-7
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    • 1997
  • Simulation is commonly used to find the best values of decision variables for problems which defy analytical solutions. "Simulation Optimization" technique is used to optimize the expressed in analytical of mathematical models. In this research, we will study Reverse-Simulation optimization method which is quite different from current simulation optimization methods in literature. We will focus on the on-line determination of steady-state method which is very important issue in Reverse-Simulation optimization, and the construction of Reverse-Simulation algorithm with expert systems. Especially, in the case of multiple objectives because of the dependency of simulation model, all objectives do not satisfied simulataneously. In this paper, therefore, we process simulation optimization using objectives with priority to optimize multiple objectives under single run.ingle run.

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

  • 곽병철;양해원
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.24 no.4
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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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Study on parallel algorithmfor falult simulation (고장시뮬레이션의 병렬화 알고리듬에 관한 연구)

  • 송오영
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.21 no.11
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    • pp.2966-2977
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    • 1996
  • As design of very large circuits is made possible by rapid development of VLSI technologies, efficient fault simulation is needed. Ingeneral, fault simulation requires many computer resources. As general-purpose multiprocessors become more common and affordable, these seem to be an attractive and effective alternative for fault simulation. Efficient fault simulation of synchronous sequential circuits has been reported to be attainably by using a linear iterative array model for such a circuit, and combining parallel fault simulation with russogate fault simulation. Such fault simulation algorithm is parallelized on a general-purpose multiprocessor with shard memory for acceleration of fault simulation. Through the experimenal study, the effect of the number of processors on speed-up of simulation, processor utilization, and the effect of multiprocessor hardware on simulation performance are studied. Some results for experiments with benchmark circuits are shown.

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Web-Based Simulation under Distributed Environment (분산 환경하에서의 웹기반 시뮬레이션에 관한 연구)

  • 이영해
    • Journal of the Korea Society for Simulation
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    • v.7 no.2
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    • pp.79-90
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    • 1998
  • This paper introduces the concept of web-based simulation and suggests the structure of web-based simulation which reduces the simulation run time and performs simulations in efficient way under distributed environments. Since its introducing in 1996, web-based simulation has been studied only with a tool of applet, but in this paper a method of server applications for client applets will be used. In server application, server transfers objects requested by clients such as simulation engines, reports, files. After each client connects to web-server, and then server allocates simulation modules to connected clients. These work magnify the transferring applets from server and simulation models which were made by clients. This paper also processes a structure for managing efficiently web-based simulation under distributed environment and steps in which clients connect, model, simulate with distributed structure, and programs of proposed structure.

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A Visual Modeling Environment for Web-based Simulation (웹 기반 시뮬레이션을 위한 시각적 모델 개발 환경)

  • 김기형
    • Journal of the Korea Society for Simulation
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    • v.8 no.1
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    • pp.101-111
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    • 1999
  • The Web-based simulation was introduced for conducting simulation experiments in the Internet and the Web. Due to the use of the Java language, the Web-based simulation can have such characteristics as reusability, portability, and the capability of execution on the Web. Most of existing Web-based simulation tools have focused mainly on the development of the runtime simulation libraries and mechanisms on the Web. Thus, the model development work in such Web-based simulation tools still requires hand-written coding of model developers. This paper presents a visual model development environment for the Web-based simulation. The proposed environment provides a framework for model development and animation. To show the effectiveness of the proposed environment, we perform simulation experiments for transaction routing algorithms in a distributed transaction processing system.

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