• Journal of the Korea Society for Simulation
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• v.4 no.2
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• pp.17-30
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• 1995

One of many factors that influences the profit of an enterprise is the amount of the stock in an enterprise. When the stock amounts are optimal the economic burden of the enterprise decreases which in turn results in the optimum number of employment and spatial utilization of storages. The purpose of this study is the simulation modeling of a material stock control system using DEVS models in order to get the most suitable stock amounts. The stock within an enterprise is built by the orders from outside world. The effect on the stock by the factors such as order, delivery, and production components has been analyzed based on simulation results.

• Journal of the Korea Society for Simulation
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• v.8 no.4
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• pp.109-124
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• 1999

The major objective of this research is to design and build the variable structure DEVS modeling & simulation framework. To do this, we have proposed the direct message passing mechanism between the model and its simulator to deal with the structural demand from the model during the simulation. In this approach, four types of basic messages are introduced for the vertical(creation/deletion of the child) and horizontal(creation/deletion of the brother) structural changes. Proposed methodology has been successfully applied to the multi-processor system and the forest fire information system.

• Journal of the Korea Society for Simulation
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• v.5 no.2
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• pp.41-58
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• 1996

The Discrete Event Systems Specification(DEVS) formalism specifies a discrete event system in a hierarchical, modular form. This paper presents a distributed simulation environment D-DEVSim++ for models specified by the DEVS formalism. D-DEVSim++ employs a new simulation scheme which is a hybrid algorithm of the hierarchical simulation and Time Warp mechanisms. The scheme can utilize both the hierarchical scheduling parallelism and the inherent parallelism of DEVS models. This hierarchical scheduling parallelism is investigated through analysis. Performance of the proposed methodology is evaluated through benchmark simulation on a 5-dimensional hypercube parallel machine. The performance results indicate that the methodology can achieve significant speedup. Also, it is shown that the analyzed speedup for the hierarchical scheduling time corresponds the experiment.

• Proceedings of the Korea Society for Simulation Conference
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• 1992.10a
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• pp.5-5
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• 1992

The DEVS(discrete event system specification) formalism describes a discrete event system in a hierarchical, modular form. DEVSIM++ is C++ based general purpose DEVS abstract simulator which can simulate systems to be modeled by the DEVS formalism in a sequential environment. We implement P-DEVSIM++ which is a parallel version of DEVSIM++. In P-DEVSIM++, the external and internal event of models can be processed in parallel. To process in parallel, we introduce a hierarchical distributed simulation technique and some optimistic distributed simulation techniques. But in our algorithm, the rollback of a model is localized itself in contrast to the Time Warp approach. To evaluate its performance, we simulate a single bus multiprocessor architecture system with an external common memory. Simulation result shows that significant speedup is made possible with our algorithm in a parallel environment.

• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.4
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• pp.61-70
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• 2006

This paper is to describe LYNX-ESM Simulation System to simulate for EW operating environment analysis and system performance verification of LYNX-ESM system using Discrete Event Simulation(DEVS) Methodology. This system consists of 3 PC with TCP/IP network. Each PC is loaded with Modeling & Simulation program based DEVS. Each connected program conducts EW simulation. As a result, we analyze the operating environment of the maritime EW threat, simulate the EW threat discrimination and geolocation capability, and estimate the LYNX-ESM system effectiveness before real LYNX-ESM system development.

• Proceedings of the Korea Society for Simulation Conference
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• 2005.05a
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• pp.123-128
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• 2005

War-game modeling and simulation system have been developed and applied to virtual tactical training both inside and outside of country However, most existing models have been developed for individual purpose based on the simple platform modeling such as physical modeling, visual modeling, and conceptual modeling. Thus, those modeling and simulation system cannot support the interoperability, expensively, variety and reusability. To deal with these problems, the paper propose an integrated design methodology for the War-game systems based on the DEVS/HLA.

• Journal of the Korea Society for Simulation
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• v.21 no.4
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• pp.35-46
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• 2012

As complexity of real-time systems is being increased ad hoc approaches to analysis of such systems would have limitations in completeness and coverability for states space search. Formal means using a model-based approach would solve such limitations. This paper proposes a model-based formal method for logical analysis, such as safety and liveness, of real-time systems at a discrete event system level. A discrete event model for real-time systems to be analyzed is specified by DEVS(Discrete Event Systems Specification) formalism, which specifies a discrete event system in hierarchical, modular manner. Analysis of such DEVS models is performed by Communicating DEVS (C-DEVS) formalism of a timed global state transition specification and an associated analysis algorithm. The C-DEVS formalism and an associated analysis algorithm guarantees that all possible states for a given system are visited in an analysis phase. A case study of a safety analysis for a rail road crossing system illustrates the effectiveness of the proposed method of the model-based approach.

• Korean Journal of Computational Design and Engineering
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• v.15 no.4
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• pp.279-288
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• 2010

In this paper, a DEVS(Discrete EVent Systems Specification)-HLA(High Level Architecture) interface was developed in order to perform the simulation using the combined discrete event and discrete time simulation model architecture in a distributed environment. The developed interface connects the combined simulation model with the HLA/RTI(Run-Time Infrastructure) which is an international standard middleware for distributed simulation. The interface consists of an interface model, a model interpreter, and a distributed environment interpreter. The interface model was defined by using the combined simulation architecture in order to easily connect the existing combined simulation model without modification with the HLA/RTI. The model interpreter takes charge of data transmission between the interface model and the combined simulation model. The distributed environment interpreter takes charge of data transmission between the interface model and the HLA/RTI. To evaluate the applicability of the developed interface, it was applied to the diving simulation of a submarine in a distributed environment. The result shows that a simulation result in a distributed environment using the interface is the same to the result in a single computing environment.

• KIISE Transactions on Computing Practices
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• v.21 no.7
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• pp.488-493
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• 2015

An AddSIM(Adaptive distributed and parallel Simulation environment for Interoperable and reusable Models) is an integrated engagement simulation environment with high-resolution weapon system models for estimation and analysis of their performance and effectiveness. AddSIM can simultaneously handle the continuous dynamical system models based on continuous time, and command, control(C2) and network system models based on a discrete event. To accommodate legacies based on DEVS(Discrete Event System Specification) modeling, DEVS legacies must first be converted into AddSIM models. This paper describes how to implement DEVS models on AddSIM. In this study a method of mapping from hierarchical DEVS models to AddSIM players was developed: The hierarchical DEVS model should be flattened into a one layered model and four DEVS functions of the model, external transition, internal transition, output and time advance, should be mapped into functions of the AddSIM player.

• Proceedings of the Korea Society for Simulation Conference
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• 1998.03a
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• pp.91-95
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• 1998

기존의 이산 사건 시스템 시뮬레이션 환경들은 Interoperability의 문제, Portability 문제로 인하여 Internet과 Web상에서 분산 시뮤레이션이 불가능하다. 본 논문에서는 이러한 제약을 해결하고자 자바를 사용하여 DEVS(Discrete Event Systems Specification)형식혼을 구현하여 Internet/Web 상에서 시뮬레이션이 가능한 DEVSim-Java 환경을 설계하고 구현하였다. DEVSim-Java를 사용하여 시뮬레이션 환경을 구현함으로써 원격지에서 개발된 시뮬레이션 모델들을 인터넷을 통하여 재사용 하는 remote model-base(RMB) 개념을 제안된다. DEVSim-Java는 자바의 장점을 이용하여 시뮬레이션 과정을 애니메이션으로 잘 나타낼수 있고, 시뮬레이션의 결과를 Graphical Analyzer를 통해 분석할 수 있게 된다.