• International Journal of CAD/CAM
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• 제4권1호
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• pp.19-32
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• 2004

This paper presents a new approach to create 3D visualization from discrete simulation results. This approach connects discrete event simulation directly to 3D animation with its novel methods that analyze and convert discrete simulation results into animation events to trigger 3D animation. In addition, it constructs a 3D animation framework for the visualization of discrete simulation results. This framework supports the reuse of both the existing 3D animation objects and behavior components, and allows the rapid development of new 3D animation objects by users with no special knowledge in computer graphics. This approach has been implemented with the software component technology. As an application in virtual manufacturing, visualizations of an electronics assembly factory are also provided in the paper to demonstrate the performance of this new approach.

• 대한조선학회논문집
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• 제47권2호
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• pp.248-257
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• 2010

In this study, a discrete event and dynamic-based discrete time combined simulation modeling architecture, which can be used to calculate equations of motions among discrete events, is developed. This is composed of a command model, which is in charge of discrete event simulation, a numerical integration model, which finds motions by numerically integrating equations of motions, and an external force and control force model, which calculates the force and transmits it to the equations. Using this architecture, we can develop dynamic-based simulation by simply connecting and combining models, and handle simultaneously discrete event and discrete time simulation. To verify the efficiency of the architecture, it is applied to the submarine diving and surfacing simulation.

• 한국시뮬레이션학회논문지
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• 제18권4호
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• pp.29-37
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• 2009

본 논문은 기존의 멀티 리스트 기반 엠리스트(MList)의 성능을 개선하기 위하여 동적 쉬프트 방식을 적용한 방법을 소개한다. 개선된 엠리스트는 일정한 수의 이벤트가 Tier 3에 쌓이게 되면 삭제 이벤트가 발생하지 않더라도 자동 쉬프트 작업을 통해 Tier 3에 저장된 이벤트들을 Tier 2의 새로운 칼렌다 큐로 이동시킨다. 즉, 기존에는 Tier 2에 하나의 칼렌다 큐가 있었으나, 개선된 방법에서는 다수의 칼렌다 큐가 동적으로 생성, 삭제된다. 이러한 동적 구조는 저장된 이벤트 수에 따라 적응력을 갖는 장점을 가져 성능측정 실험 결과 동적 쉬프트를 적용한 엠리스트는 기존의 엠리스트에 비해 20% 이상의 성능개선을 보였다.

• 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.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.91.5-91
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• 2002

$\textbullet$ Visualization $\textbullet$ Animation $\textbullet$ Simulation $\textbullet$ Software Components $\textbullet$ Workflow Management

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1996년도 추계학술대회
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• pp.74-79
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• 1996

This paper describes a methodology for the development of models of discrete event system(DES). 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 couple DES models within a framework. The structure employs the DEVS formalism for the DES models. The proposed formal structure has been applied to develop a DEVS model for the human cardiovascular system. For this, the cardiac cycle is partitioned into a set of phases based on events identified through VisSim simulation in the CS of the electrical analog model. VisSim is the simulation tool of visual environment for developing continuous, discrete, and hybrid system models and performing dynamic simulation. For each phase, a CS of the electrical analog model for the cardiovascular system has been simulated by VisSim 2.0. To validate this model, first develop the DEVS model, then simulate the model in the DEVSIM++ environment. It has same simulation results for the data obtained from the CS simulation using VisSim. The comparison shows that the DEVS model represents dynamics of the human heart system at each phase of cardiac cycle.

• 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.

• International Journal of Naval Architecture and Ocean Engineering
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• 제9권4호
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• pp.446-459
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• 2017

Naval ships are assigned many and varied missions. Their performance is critical for mission success, and depends on the specifications of the components. This is why performance analyses of naval ships are required at the initial design stage. Since the design and construction of naval ships take a very long time and incurs a huge cost, Modeling and Simulation (M & S) is an effective method for performance analyses. Thus in this study, a simulation core is proposed to analyze the performance of naval ships considering their specifications. This simulation core can perform the engineering level of simulations, considering the mathematical models for naval ships, such as maneuvering equations and passive sonar equations. Also, the simulation models of the simulation core follow Discrete EVent system Specification (DEVS) and Discrete Time System Specification (DTSS) formalisms, so that simulations can progress over discrete events and discrete times. In addition, applying DEVS and DTSS formalisms makes the structure of simulation models flexible and reusable. To verify the applicability of this simulation core, such a simulation core was applied to simulations for the performance analyses of a submarine in an Anti-SUrface Warfare (ASUW) mission. These simulations were composed of two scenarios. The first scenario of submarine diving carried out maneuvering performance analysis by analyzing the pitch angle variation and depth variation of the submarine over time. The second scenario of submarine detection carried out detection performance analysis by analyzing how well the sonar of the submarine resolves adjacent targets. The results of these simulations ensure that the simulation core of this study could be applied to the performance analyses of naval ships considering their specifications.

• 한국시뮬레이션학회논문지
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• 제32권1호
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• pp.1-11
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• 2023

스마트 팩토리 환경과 디지털 트윈 환경이 구축되며 요즘의 공장은 방대한 생산 데이터를 축적하고 공정 현황에 대해 실시간으로 사용자 편의에 맞는 시각화된 결과물로 관리되고 있다. 생산 제품의 다변화에 따른 공정의 복잡도가 증대되어 생산일정 계획이 어려워지고, 자동화 설비가 구축되는 상황에서 납기 지연을 예방하고, 공장의 변동성에 대한 사전 예측을 위한 방안으로 생산 시뮬레이션 기법이 각광받고 있다. 디지털 트윈 환경의 발전과 함께 신규 패키지가 개발되고 기존 패키지들의 기능 업데이트가 됨에 따라 상용 제품별 특성이나 장단점이 명확히 정의되지 않아 사용자들이 어떠한 패키지를 활용하여 시뮬레이션 개발을 진행하는 지에 대한 의사결정이 어려운 상황이다. 이에 본 연구에서는 이산적으로 발생되는 사건을 기반으로 수행하는 이산사건 시뮬레이션(DES, Discrete Event Simulation)의 개념을 정의하고, 다양한 시뮬레이션 패키지에 대한 특성을 비교 분석하고자 한다. 이를 위해 10년간 이산사건 시뮬레이션 패키지를 사용하여 실제 문제를 해결한 연구들을 분석하였고, 사용 빈도가 높은 패키지 세 가지를 도출하였다. 또한, 각 패키지들의 시뮬레이션 기법, 주요 업종, 시뮬레이션을 수행한 대상, 사용한 국가 등으로 분류하여 DES 소프트웨어의 특성과 사용 현황에 대한 분석을 진행하였다. 본 연구 결과는 추후 이산사건 시뮬레이션 패키지 선택에 어려움을 겪는 기업과 사용자에게 선택의 기반을 제공하며 기초자료로 사용될 것으로 판단한다.

• 한국시뮬레이션학회논문지
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• 제20권1호
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• pp.87-96
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• 2011

DEVS는 이산 사건 시스템을 명세하는 집합론에 근거한 수학적인 틀이다. 이러한 DEVS를 통해 시스템을 시뮬레이션할 때는 명세된 DEVS로부터 구현된 모델과 시뮬레이션 엔진으로 이루어진 실행 환경이 필요하다. 시뮬레이션 엔진은 스케줄링 알고리즘을 통해 모델을 해석하고 실행하는데, 주로 DEVS의 계층적이고 모듈러한 특성을 따라 계층적인 스케줄링 방법을 사용한다. 그러나 이 방법은 계층적인 구조로 인해 시간 관리와 메시지 패싱에 있어서 오버헤드가 존재한다. 본 논문에서는 이러한 오버헤드를 해결하기 위해 이벤트 지향 시뮬레이션을 적용한다. 이벤트 지향의 시뮬레이션은 이벤트에 의해서 모델이 실행되며 이벤트 리스트에 의해 이벤트가 관리된다. 이벤트 리스트에 의해서 시간 관리가 되고 메시지 패싱이 이루어지기 때문에 계층적인 오버헤드를 줄이고 성능 향상을 이룰 수 있다. 본 논문은 이벤트 리스트를 이용한 실행 환경을 제안하고 이러한 실행 환경을 위한 모델 구현 방안에 대해 논하며, 각 실행 환경의 성능을 비교, 분석한다.