• Structural Engineering and Mechanics
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• 제37권1호
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• pp.17-37
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• 2011

This paper presents a new Internet-based computational framework for the realistic simulation of multi-scale response of structural systems. Two levels of parallel processing are involved in this frame work: multiple local distributed computing environments connected by the Internet to form a cluster-to-cluster distributed computing environment. To utilize such a computing environment for a realistic simulation, the simulation task of a structural system has been separated into a simulation of a simplified global model in association with several detailed component models using various scales. These related multi-scale simulation tasks are distributed amongst clusters and connected to form a multi-level hierarchy. The Internet is used to coordinate geographically distributed simulation tasks. This paper also presents the development of a software framework that can support the multi-level hierarchical simulation approach, in a cluster-to-cluster distributed computing environment. The architectural design of the program also allows the integration of several multi-scale models to be clients and servers under a single platform. Such integration can combine geographically distributed computing resources to produce realistic simulations of structural systems.

• International Journal of Naval Architecture and Ocean Engineering
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• 제4권3호
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• pp.211-227
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• 2012

To implement a combined discrete event and discrete time simulation such as submarine diving simulation in a distributed environment, e.g., in the High Level Architecture (HLA)/Run-Time Infrastructure (RTI), a HLA interface, which can easily connect combined models with the HLA/RTI, was developed in this study. To verify the function and performance of the HLA interface, it was applied to the submarine dive scenario in a distributed environment, and the distributed simulation shows the same results as the stand-alone simulation. Finally, by adding a visualization model to the simulation and by editing this model, we can confirm that the HLA interface can provide user-friendly functions such as adding new model and editing a model.

• 한국시뮬레이션학회논문지
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• 제7권2호
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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.

• 한국시뮬레이션학회논문지
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• 제22권2호
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• pp.73-83
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• 2013

본 연구에서는 수중 환경에서의 교전급 모의를 위한 분산 시뮬레이션 시스템에서 모니터링 시스템을 설계 및 구축한다. 국방 분야에서 모델링 및 시뮬레이션(M&S)을 통한 검증은 비용, 시간, 및 노력의 측면에서 효율적인 접근 방법으로 주목되어 왔으며, 무기체계의 도입의 각 단계에서 시뮬레이션 기반의 획득(Simulation-Based Acquistion : SBA)이 필수 프로세스로 지정되었다. 그러나 복잡한 전장 환경을 전반적으로 묘사하는 방대한 시뮬레이션 시스템의 개발은 많은 자원을 요구한다. 따라서 이미 개발된 한정적인 목적을 갖는 시뮬레이터들을 조합하여 새로운 시뮬레이션 시스템을 구축하는 분산 시뮬레이션 시스템을 통해 시스템의 개발에 투입되는 비용 및 시간의 절약이 가능하다. 분산 시뮬레이션 시스템 중 High-Level Architecture(HLA)는 미국 표준으로 지정되었고, 이것을 구현한 Run-Time Infrastructure(RTI)는 미들웨어로서 효율적인 분산 시뮬레이션 시스템의 구축을 도와준다. 본 연구의 핵심 목적은 HLA/RTI 기반의 수중 교전 모의 시뮬레이션 시스템에서 수행 목적에 적합한 모니터링 요소를 도출하고, 그 체계 및 표현 방안을 설계하여 시뮬레이션을 분석하는 시스템의 구현에 있다.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 1995년도 추계학술대회발표논문집; 서울대학교, 서울; 30 Sep. 1995
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• pp.46-58
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• 1995

Although numerous distributed database design models and solution algorithms have been developed, very few have been validated. Validation is critical to the successful application of such models to distributed database design. In this paper, we develop a simulation system for distributed database design. We then analyze and validate an average response time model using simulation. The simulation results demonstrate that the average response time model is reasonably accurate.

• 한국시뮬레이션학회논문지
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• 제14권1호
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• pp.19-32
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• 2005

In this study, a distributed simulation of Petri net models under HLA/RTI framework is considered. Throughout our modeling experiences, it is recognized that the proper use of interface specification and time management services are important in order to achieve successful implementation of RTI. The interfacing tokens between Petri net models are distinguished as information entity and physical entity. Both entities are modeled as InteractionClass in order to send and receive messages. For the synchronization of local simulation clocks, a conservative method with NERA service is considered. A cell manufacturing system is modeled and implemented with RTI to illustrate the distributed simulation of Petri net models.

• 한국정보처리학회논문지
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• 제6권1호
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• pp.57-65
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• 1999

규모가 크고 복잡하며, 사용자와 상호 작용하는 시뮬레이션은 처리되는 메시지 수가 매우 많으므로 메시지의 순차적 시뮬레이션이 더 효율적이라 생각할 수 있다. 또한 사용자가 많은 훈련용 시뮬레이션은 지역적으로 분산되고 사용자의 추가 요구 사항의 증가로 시스템의 운용 및 유지보수 비용이 많이 든다. 따라서 시뮬레이션에 웹 기술의 적용은 이러한 문제를 해결할 수 있는 하나의 방법이 될 수 있다. 하지만 웹의 동적인 환경은 분산 처리되는 사건들의 인과성 오류를 유발 할 수 있다. 따라서 본 논문에서는 분산 처리되는 시뮬레이션 서버와 웹 브라우저의 클라이언트 사이에 상호작용을 위한 클라이언트-서버 모델을 제시하고 구현하였으며, 구현에는 웹 기술에 적합한 자바와 자바 분산 객체 모델을 사용하였다. 제시된 모델에 의한 실험결과 인터넷의 동적인 환경에 분산 시뮬레이션이 정확하게 수행되었음을 확인할 수 있었다.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2002년도 추계학술대회 논문집
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• pp.157-162
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• 2002

A distributed simulation with HLA/RTI provides stable and satisfactory results. In this study, a distributed simulation of Petri net models under the HLA/RTI framework is considered. Throughout our experiences, it is recognized that the proper use of interface specification and time management services are important in order to achieve successful implementation of RTI. The interfacing tokens that are delivered to other models are distinguished as information entity and physical entity. Both entities are modeled as Interaction Class in order to send and receive messages. In synchronizing local simulation clocks, a conservative method with NERA service is considered. A eel manufacturing system is modeled and implemented with RTI to illustrate the distributed simulation of Petri net models.

• Asia pacific journal of information systems
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• 제7권3호
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• pp.23-37
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• 1997

Although numerous models and solution algorithms to design efficient distributed databases have been developed, very few have been validated for their effectiveness. In this paper, we develop a simulation system which can be used to analyze and validate the average response time of distributed database designs. Our simulation system models comprehensive query processing strategies such as semijoin as well as a concurrency control mechanism We analyze and validate an average response time distributed database design model using our simulation system.

• 한국시뮬레이션학회논문지
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• 제13권4호
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• pp.43-53
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• 2004

The distributed OCSP (Online Certificate Status Protocol), composed of multiple responders, is a model that enhances the utilization of each responder and reduces the response time. In a multi-user distributed environment, load balancing mechanism must be developed for the improvement of the performance of the whole system. Conservative load balancing algorithms often ignore the communication cost of gathering the information of responders. As the number of request is increased, however, fail to consider the communication cost may cause serious problems since the communication time is too large to disregard. We propose an adaptive load balancing algorithm and evaluate the effectiveness by performing modeling and simulation. The principal advantage of new algorithm is in their simplicity: there is no need to maintain and process system state information. We evaluated the quality of load balancing achieved by the new algorithm by comparing the queue size of responders and analyzing the utilization of these responders. The simulation results show how efficiently load balancing is done with the new algorithm.