• Structural Engineering and Mechanics
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• v.37 no.1
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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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• v.4 no.3
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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.

• 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.

• Journal of the Korea Society for Simulation
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• v.22 no.2
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• pp.73-83
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• 2013

This paper presents design and implementation of the monitoring system for the distributed simulation of underwater warfare. As importance of defense modeling and simulation(M&S) has raised, Simulation-Based Acquisition(SBA) was authorized for an obligatory process in the development process of weapon systems. Yet, it requires tremendous resources to develop a large-scale simulation system that describes complex and broad battlefields. Therefore, an approach of the distributed system was devised to develop a new simulation system combining legacy simulators that were developed for confined purpose and sole operations. High-Level Architecture(HLA) of distributed systems is a standardized protocol by IEEE for the distributed simulation system and Run-Time Infrastructure(RTI) is an implementation of HLA to structure efficient distributed systems. The main objective of this paper is to derive appropriate monitoring factors for underwater warfare simulation, design and implementation of the monitoring system to analyze the factors based on HLA/RTI.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.09a
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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.

• Journal of the Korea Society for Simulation
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• v.14 no.1
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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.

• The Transactions of the Korea Information Processing Society
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• v.6 no.1
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• pp.57-65
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• 1999

The simulation which is larger scale, complex and interactive with clients treat a lot of messages. It can be thinking more efficient distributed simulation than sequential one. The training simulation with multi-users is geographically distributed, and required high cost to operate and maintain system as increasing user requirements. The adaptation of web technology to the simulation can be a way to solves it without cost added. But dynamic web environment can causes causality error of events. This paper is concerned with client-server model, which supports interaction between distributed simulation server and web browser, and it is implemented by Java distributed object model. the result have shown that the distributed simulation is performed correctly on dynamic environment.

• Proceedings of the Korea Society for Simulation Conference
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• 2002.11a
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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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• v.7 no.3
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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.

• Journal of the Korea Society for Simulation
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• v.13 no.4
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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.