• 한국군사과학기술학회지
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• 제10권3호
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• pp.90-99
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• 2007

The DEVS formalism has the well-defined relationship between its model and simulator. However, it does not define the connection between its model and experimental frame needed when a simulator's implemented with it. So, in most DEVS based simulators, the modules of the two parts are tangled, so that changing and reusing them is not easy. This paper proposes a method to improve the changeability of the experimental frame and the reusability of the model by modularizing the two parts using the AOP technology. I applied the new method to a real project, and the result shows that it improves the two qualities effectively than before.

• 한국멀티미디어학회논문지
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• 제22권8호
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• pp.887-896
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• 2019

In this paper, we discuss an optimization approach for time-synchronizations in networked simulators. This method is a sub-technology that is required to combine heterogeneous simulators into a single simulation. In previous time-synchronization studies, they had built a network system among networked simulators. The network system collects network packets and adds time-stamps to the networked packets based on the time that occurs in events of simulation objects in the individual simulators. Then, it sorts them in chronological order. Finally, the network system applies time-synchronization to each simulator participating in interworking sequentially. However, the previous approaches have a limitation in that other participating simulators should wait for while processing an event in a simulator in a time stamp order. In this paper, we attempt to solve the problem by optimizing time-synchronizations in networked simulation environments. In order to prove the practicality of our approach, we have conducted an experiment. Finally, we discuss the contributions of this paper.

• 한국시뮬레이션학회논문지
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• 제1권1호
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• pp.64-76
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• 1992

The DEVS(discrete event system specificaition) formalism specifies a discrete event system in a hierarchical, modular form. DEVSIM++ is a C++based general purpose DEVS abstract simulator which can simulate systems modeled by the DEVS formalism in a sequential environment. This paper describes P-DEVSIM++which is a parallel version of DEVSIM++ . In P-DEVSIM++, the external and internal event of DEVS models can by processed in parallel. For such processing, we propose a parallel, distributed optimistic simulation algorithm based on the Time Warp approach. However, the proposed algorithm localizes the rollback of a model within itself, not possible in the standard Time Warp approach. An advantage of such localization is that the simulation time may be reduced. 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.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 1992년도 제2회 정기총회 및 추계학술 발표회 발표논문 초록
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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.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2001년도 The Seoul International Simulation Conference
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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.

• 한국군사과학기술학회지
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• 제14권3호
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• pp.405-413
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• 2011

Defense Systems Test Center in ADD supports increasingly various missile test requirements such as higher altitude event, multi target operation and low-altitude, high velocity target tracking. In this paper, we have proposed the development of instrumentation radar tracking status simulator based on virtual reality. This simulator can predict the tracking status and risk of failure using several modeling algorithms. It consists of target model, radar model, environment model and several algorithms includes the multipath interference effects. Simulation results show that the predict tracking status and signal are similar to the test results of the live flight test. This simulator predicts and analyze all of the status and critical parameters such as the optimal site location, servo response, optimal flight trajectory, LOS(Line of Sight). This simulator provides the mission plan with a powerful M&S tool to rehearse and analyze instrumentation tracking radar measurement plan for live flight test at DSTC(Defense Systems Test Center).

• 한국시뮬레이션학회논문지
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• 제9권1호
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• pp.39-54
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• 2000

Presented in this paper is a modeling and simulation methodology for 3 dimensional man-made systems. Based on DEVS(discrete event system specification) formalism[13], we propose GK-DEVS (geometrical and kinematic DEVS) formalism to describe the geometrical and kinematic structure and continuous state dynamics. To represent geometry and kinematics, we add a hierarchical structure to the conventional atomic model. In addition, we employ the "empty event" and its external event function for continuous state changing. In terms of abstract simulation algorithm[13], the simulation method of GK-DEVS, named GK-Simulator, is proposed for combined discrete-continuous simulation. Using GK-DEVS, the simulation of an FMS(flexible manufacturing system) consisting of a luring machine, a 3-axis machine and a RGV-mounted robot has been peformed.en peformed.

• 한국컴퓨터정보학회논문지
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• 제26권1호
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• pp.171-178
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• 2021

본 논문에서는 C/C++ 기반 이산 사건 시스템 명세(DEVS) 시뮬레이션에서 전송 메시지 변경을 탐지하는 기법을 제안한다. 모델 인스턴스가 생성한 메시지가 다른 모델 인스턴스로 전달될 때, 메시지가 수신자 중 일부가 이를 수정할 수도 있다. 이러한 변경은 시뮬레이션 결과를 오염시킬 수 있으며, 오염된 시뮬레이션 결과는 잘못된 의사결정으로 이어질 수 있다. 제안 기법에서는 모든 모델 인스턴스가 전송 메시지의 사본을 저장한다. 전송 메시지가 삭제되기 전, 인스턴스는 저장된 메시지와 전송 메시지를 비교한다. 변경이 탐지되면 현재 시뮬레이션 실행을 중단시킨다. 모든 절차는 시뮬레이터 인스턴스에 의해 자동으로 수행된다. 그러므로 제안 기법은 개발자에게 시큐어 코딩을 준수하거나 특정 코드를 추가하도록 강요하지 않는다. 제안 기법의 성능을 기존 DEVS 시뮬레이터와 비교한다.

• 전기학회논문지
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• 제67권2호
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• pp.325-330
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• 2018

In this paper, we investigated the impedance method for searching fault detection point in case of an accident in the AC electric railway AT feeding system. For this purpose, simulation circuit modeling and prototype hardware are made based on the known numerical analysis. As a result of simulation modeling of the feeding system based on the numerical analysis of the impedance method confirmed that the modeling was properly implemented with an average error rate of 0.07%. Also, as a result of fault event by hardware simulator, it was confirmed that the breaker operation time is shortened and the fault current is decreased while the voltage is close to the supply voltage in the transient state as the point of the fault accident moves away from the substation(SS).

• 한국시뮬레이션학회논문지
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• 제4권2호
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• pp.1-16
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• 1995

The performance of a computer system depends on the system architecture and workload, and the high performance required in many applications can be achieved by the scalability of the system architecture and workload. This paper presents scalable workload, a performance metric of scalable speedup and hierarchical modeling for the scalable computer system as well as the development of the object-oriented simulator spmplC++ Which is an advanced C++ version of the discrete event-driven simulation environment smplE. In addition, this paper presents two examples of applying scalable speedup, hierarchical modeling and simulator smplC++ to analyze the performance effect of the sclcbility in a multiprocessor system and a network-based client/server system.