• 한국시뮬레이션학회논문지
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• 제4권1호
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• pp.13-24
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• 1995

In general, simulation and analytic method are used for real system analysis. However, or date, there has been only the theoretical works on each approach. Therefore it is required that we study on the relationship between each approaches to obtain more reliable and correct system analysis results. In this paper, using SPN(Stochasitc Petri Net) formalism, we propose the method of output prediction of the DEVS(Discrete Event system Specification) simulation. For this we suggest a transformation algorithm which transform SPN form DEVS formalism based on the event scheduling world view and a verification algorithm for it. We then show an example to apply it to the real system, such that the Grocery Store System.

• 대한의용생체공학회:의공학회지
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• 제16권4호
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• pp.415-424
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• 1995

Combined models, specified by two or more modeling formalisms, can represent a wide variety of complex systems. This paper describes a methodology for the development of combined models in two model types of discrete event and continuous process. The methodology is based on transformation of continuous state space into discrete one to homomorphically represent dynamics of continuous processes in discrete events. This paper proposes a formal structure which can combine model of the DES and the CS within a framework. The structure employs the DEVS formalism for the DES models and differential or polynomial equations for the CS models. To employ the proposed structure to specify a DEVS/CS combined model, a modeler needs to take the following steps. First, a modeler should identify events in the CS and transform the states of the CS into the DES. Second, a modular employs the formalism to specify the system as the DES. Finally, a moduler developes sub-models for the CS and continguos states of the DES and establishs one-to-one correspondence between the sub-models and such states. The proposed formal structre has been applied to develop a DEVS/CS combined model for the human cardiovascular system. For this, the cardiac cycle is partitioned into a set of phases based on events identified through observation. For each phase, a CS model has been developed and associated with the phase. To validate the DEVS/CS combined model developed, then simulate the model in the DEVSIM + + environment, which is a model simulation results with the results obtained from the CS model simulation using SPICE. The comparison shows that the DEVS/CS combined model adequately represents dynamics of the human heart system at each phase of cardiac cycle.

• 한국CDE학회논문집
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• 제18권3호
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• pp.224-233
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• 2013

For the scheduling and the job assignment of the ship hull production design which is a process-based work, we suggest the simulation-based scheduling using the discrete-event-based business process simulation. First, we analyze the ship hull production design process from the perspective of a job assignment to make it into the simulation model using DEVS (Discrete Event System Specification) which is the representative modeling method for a discrete-event simulation. Based on the APIs of the open-source discrete-event simulation engine, we implement the simulation using the Groovy script. We develop the scenario generator in which the user defines detail information of the construction drawing and its member blocks, and design engineers information, and the various setting for the simulation including the job assignment strategy. We use the XML files from this scenario generator as inputs of simulation so that we can get simulation result in forms of Gantt chart without changes of the simulation model.

• 대한조선학회논문집
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• 제61권3호
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• pp.152-160
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• 2024

In the event of a maritime accident, search plans have traditionally been planned using experiential methods. However, these approaches cannot guarantee safety when the scale of a maritime accident increases. Therefore, this study proposes a model utilizing discrete event simulation (DES) to predict the diving time for compartment searches of a ship located on the seabed. The discrete event simulation model was created by applying the DEVS formalism. The M/V Sewol sinking was used as an example to simulate how to effectively navigate compartments of different sizes. The simulation results showed the optimal dive time with the number of decompression chambers needed to navigate the compartment as a variable. Based on this, we propose a methodology for efficient navigation planning while ensuring diver safety.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 춘계학술대회
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• pp.145-149
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• 1997

This paper describes a methodology for the development of models of discrete event system. The methodology is based on transformation of continuous state space into discrete one to homomorphically represent dynamics of continuous processes in discrete events. This paper proposes a formal structure which can coupled discrete event system models within a framework. The structure employs the discrete event specification formalism for the discrete event system models. The proposed formal structure has been applied to develop a discrete event specification model for the complex spectral density analysis of strip for urin analyzer system. For this, spectral density data of strip is partitioned into a set of Phases based on events identified through urine spectrophotometry. For each phase, a continuous system of the continuous model for the urine spectral density analysis has been simulated by programmed C++. To validate this model, first develop the discrets event specification model, then simulate the model in the DEVSIM++ environment. It has the similar simulation results for the data obtained from the continuous system simulation. The comparison shows that the discrete event specification model represents dynamics of the urine spectral density at each phase.

• 대한조선학회논문집
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• 제47권4호
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• pp.628-645
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• 2010

To perform the engagement level simulation between the underwater vehicle model and the surface model those are constituted with various systems/ sub-systems, we implemented four different federates as a federation according to the IEEE 1516 HLA (High Level Architecture) protocol that is the international standard in the distributed simulation. Those are CFCS (Command and Fire Control System) federate, motion federate, external entities (torpedos, countermeasure and surfaceship) federate, and visualization federate that interacts with OSG (Open Scene Graph)-based visualization rendering module. In this paper, we present the detailed method about the model constitution for discrete event simulation in the distributed environment. For the sake of this purpose, we introduce the DEVS (Discrete Event System Specification)-HLA-based modeling method of the CFCS federate that reflects not only the interations between models, but also commands from user and tactics manager that is separated from the model. The CFCS federate makes decisions in various missions such as the normal diving, the barrier misision, the target motion analysis, the torpedo launch, and the torpedo evasion. In the perspective of DEVS modeling, the CFCS federate is the coupled model that has the tactical data process model, command model and fire control model as an atomic model. The message passing and time synchronization with other three federates are settled by the $m\ddot{a}k$ RTI (Runtime Infrastructure) that supports IEEE 1516. In this paper, we provides the detailed modeling method of the complicated model that has hierarchical relationship such as the CFCS system in the submarine and that satisfies both of DEVS modeling method for the discrete event simulation and HLA modeling method for the distributed simulation.

• Journal of Information Processing Systems
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• 제17권1호
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• pp.28-36
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• 2021

This paper proposes two novel methods to model and simulate a mobile Internet of Things (IoT) system using the discrete event system specification (DEVS) formalism. In traditional simulation methods, it is advantageous to partition the simulation area hierarchically to reduce simulation time; however, in this case, the structure of the model may change as the IoT nodes to be modeled move. The proposed methods reduce the simulation time while maintaining the model structure, even when the IoT nodes move. To evaluate the performance of the proposed methods, a prototype mobile IoT system was modeled and simulated. The simulation results show that the proposed methods achieve good performance, even if the number of IoT nodes or the movement of IoT nodes increases.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2005년도 춘계학술대회 논문집
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• pp.100-105
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• 2005

Development of complex discrete event simulators requires cooperation between domain experts and modeling experts who involve the development. With the cooperation the domain experts derive user requirement and modeling experts transform the requirement to a simulation model. This paper proposes a method for consistency verification of simulation model in DEVS formalism against the user requirement in UML diagrams. It also presents an automated tool, called VeriDEVS, which implements the proposed method. Inputs of VeriDEVS are three UML diagrams, namely use case, class and sequence diagrams, and DEVS Graph, all in Visio; outputs of a verification result is represented in PowerPoint files.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 1999년도 추계학술대회논문집
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• pp.35-42
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• 1999

In order to cope with the changes of container terminal situation in these days, many simulation studies for container terminal have been accomplished. But established simulation studies using simulation language have restrictions in model representation and difficulties in modeling of large scaled container terminal system. To make these problems better, in this paper addresses object-oriented simulation of container terminal system using a DEVS formalism. In a step of system modeling, using a DEVS formalism aim at the exact system modeling that has a basis of semantics and utilizing the object-oriented manner can flexibly cope with the changes of system environment. In this study a model was developed and verified through the simulation of some alternatives.

• 정보과학회 컴퓨팅의 실제 논문지
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• 제21권7호
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• pp.488-493
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• 2015

컴포넌트기반 체계모의환경(AddSIM)은 고해상도 공학급 무기체계를 사용하여 체계의 성능 및 효과도를 예측 분석하기 위해 개발된 무기체계 통합 모의환경이다. AddSIM을 이용한 고해상도 교전 모의 분석을 위해서는 연속시스템으로 표현되는 무기체계 공학급 모델은 물론, 지휘 통제, 네트워크 제어 모델과 같이 DEVS 형식론으로 기술된 이산사건시스템 모델을 복합적으로 사용해야 한다. 본 논문에서는 DEVS 모델과 AddSIM 플레이어 모델의 함수 간 관계 매핑(mapping)을 통해 AddSIM에서 실행 가능한 DEVS 모델 변환방법을 제시한다. 제안한 방법은 우선, 계층적으로 구성된 DEVS 모델을 단일 계층으로 변환하고, DEVS의 네 가지 함수(외부천이, 내부천이, 출력, 시간진행함수)를 AddSIM 플레이어 함수로의 변환을 주요 내용으로 한다.