• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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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.

• 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. .

• Journal of Advanced Navigation Technology
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• v.24 no.3
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• pp.184-191
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• 2020

Avionics System Integration Laboratory is the integrated test environment for integration and verification of avionics systems. When real equipment can not be used in the laboratory for various reasons, software models should be needed. Because there hasn't been any standardized method for the models so that it is difficult to reuse the developed models, the need for a framework to develop the avionics software models was emerged. We adopted DEVS(discrete event system specification) formalism as the standardized modeling method for the avionics software models. Due to DEVS formalism is based on event-driven algorithm, it doesn't accord a legacy system which has sequential and periodic algorithms. In this paper, we propose real-time event-driven modeling and simulation method for SIL to overcome these restrictions and to maximize reusability of avionics models through the analysis of the characteristics and the limitations of avionics models.

• Journal of the Korea Society for Simulation
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• v.18 no.4
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• pp.127-136
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• 2009

Modeling and Simulation, especially in mobile ad hoc network(MANET), are the most effective way to analyze performance or optimize system parameters without establishing real network environment. Focusing mainly on overall network behaviors in MANET concerns dynamics of network transport operations, which can efficiently be characterized with event based system states rather than execution details of protocols. We thus consider the network as a discrete event system to analyze dynamics of network transport performance. Zeigler's set-theoretic DEVS(Discrete Event Systems Specification) formalism can support specification of a discrete event system in hierarchical, modular manner. The DEVSim++ simulation environment can not only provide a rigorous modeling methodology based on the DEVS formalism but also support modelers to develop discrete event models using the hierarchical composition methodology in object-orientation. This environment however hardly supports to specify connection paths of network nodes, which are continuously altered due to mobility of nodes. This paper proposes a DEVS-based modeling and simulation methodology of enabling node mobility, and develops DEVS models for the mobile ad hoc network. We also simulate developed models with the DEVSim++ engine to verify the proposal.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.1
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• pp.78-85
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• 2007

A gun is still one of the major weapons of a combat ship. To assess the ship's fire control capability which is influenced by tracking system, fire control algorithm, gun, the ship itself, target behavior, environment and engagement situation, simulation system for gun-oriented engagement for surface ship is needed. This paper proposes the process for designing and implementing a gun-oriented engagement simulation system using DEVS(Discrete Event Simulation Specification), which is a formalism based on the set theory. It consists of the following activities : 1) analyzing the characteristics of a gun-oriented engagement, 2) constructing the deterministic model of the combat ship of study with DEVS, 3) modeling properties of each entity showing as stochastic errors. With this process, the gun-oriented engagement simulation system is developed and applied for the combat system under development.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1359-1363
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• 2009

The object of this research is to develop a simulation system for earthmoving operations in consideration of the impact of congestion in-between equipment and existing traffic flow around the site. The congestion in-between equipment and traffic flow affect work productivity. The conventional discrete event simulation, however, has limitations in simulating the flow of construction equipment. To consider the impact of congestion in-between equipment and existing traffic flow, in this paper, a multi-agent based simulation model that can realize characteristics of truck behavior more accurately to consider the impact of congestion was proposed. In this simulation model, multiple agents can identify environmental changes and adapt themselves to the new environment. This modeling approach is a better choice for this problem since it describes behavioral characteristics of each agent by sensing changes in dynamic surroundings. This study suggests a detailed system design of the multi-agent based simulation system.

• The Journal of Information Systems
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• v.27 no.4
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• pp.35-70
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• 2018

Purpose Recently, 3D factory simulation technology has emeged as a powerful tool for modeling and analysis of a wide range of production systems, however, it has been not paid much attention in Korea. In this context, this paper aims to provide a comprehensive literature review on discrete event simulation softwares and introduce a promising 3D factory simulation software called FlexSim and its application domains. Design/methodology/approach In order to demonstrate worldwide popularity and technical superiority of FlexSim software, we analyzed the recent list of rankings for commercial discrete simulation softwares released by winter simulation conference and users' opinions collected from business software review site. Moreover, several main application domains are derived from a review of the previous research papers that deal with applications of FlexSim software. Findings FlexSim software recently moved up the list of major commercial simulation softwares, and technical superiorities of the software demonstrate that it is a promising tool for practical 3D factory simulation. Moreover, recent research papers suggest that FlexSim software can be used as a component of smart factory system. In this context, it is expected that FlexSim software becomes more popular in the era of industry 4.0.

• Journal of the Korea Society for Simulation
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• v.17 no.4
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• pp.61-69
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• 2008

In order to evaluate the performance of priority queues for future event list in discrete-event simulations, models representing patterns of enqueue and dequeue processes are required. The time complexities of diverse priority queue implementations can be compared using the performance models. This study aims at developing such performance models especially under the environment that a developed simulation model is used repeatedly for a long period. The developed performance model is based on multi-stage Markov process models; probabilistic patterns of enqueue and dequeue are considered by incorporating non-homogeneous transition probability. All necessary parameters in this performance model would be estimated by analyzing a results obtained by executing the simulation model. A case study with a war game simulation model shows how the parameters defined in muti-stage Markov process models are estimated.

• Proceedings of the Korea Society for Simulation Conference
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• 1999.10a
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• pp.24-29
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• 1999

Proposed in this paper is a modeling and simulation methodology for a virtual manufacturing environment. Based on DEVS formalism[Zeigler 76], the proposed model, so called GKDEVS, is designed to descript the geometrical knematic structure as well as event-driven and continuous state dynamics. In terms of abstract simulation algorithm[Zeigler 84], the simulation method of GKDEVS is proposed for combined discrete-continuous simulation. Using the GKDEVS, and FMS model consisting of a turing machine, a 3-axis machine and a RGV-mounted robot is constructed and simulated.

• 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.