• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.331-336
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• 2005

A lot of manufacturing knowledge and method have applied to increase manufacturing efficiency in industry field. DES(Discrete Event Simulation) is one of solution to deal with manufacturing problems in factory. Beginning of research, old maintenance system of KNR ( Korea National Railroad) and its technical problems are basically investigated. KNR has maintained railway vehicle with their own solution based on experience. Very advanced railway vehicles such as KTX (Korea Train Express) and TTX(Tilting Train Express) will be difficult to maintain with their old maintenance method. In order to apply knowledge of DES, maintenance field of railway must be considered. Imaginary maintenance machine are selected to variable of DES. Maintenance capability of each machine will be evaluated base on imaginary data from imaginary machine. The machine could be very expensive as well as difficult to replace. Target of research is minimization of number of machine in railway workshop. So basic knowledge of discrete event simulation is introduced. Then five essential stages of discrete event simulation are provided. Each maintenance case defined as event. Each event is discrete and simulated base on different case such as one maintenance line with one machine and one maintenance line with two machines in railway workshop. simple maintenance method, discrete event simulation, will be come out very powerful in complicate maintenance system and will be helpful to reduce maintenance cost as well as maintenance labor.

• Nuclear Engineering and Technology
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• 제41권5호
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• pp.739-746
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• 2009

This paper introduces facility operation modeling and simulation based primarily on a discrete event system modeling scheme. Many modern industrial facilities are so complex that their operational status cannot be estimated by simple calculations. In general, a facility can consist of many processes and transfers of material between processes that may be modeled as a discrete event system. This paper introduces the current status of studies on operation modeling and simulation for typical nuclear facilities, along with some examples. In addition, this paper provides insights about how a discrete event system can be applied to a model for a nuclear facility. A headend facility is chosen for operation modeling and the simulation, and detailed procedure is thoroughly described from modeling to an analysis of discrete event results. These kinds of modeling and simulation are very important because they can contribute to facility design and operation in terms of prediction of system behavior, quantification of facility capacity, bottleneck identification and efficient operation scheduling.

• 한국멀티미디어학회논문지
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• 제20권7호
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• pp.1090-1101
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• 2017

This study analyzes spatial density and integration of Space Syntax and Discrete Event Simulation (DEVS) of complex system theory and analyzes spatial structure by property, type and depth. The aim of this study is to secure the validity of the theoretical application. The study evaluated the correlation between spatial density and integration by setting up eight types of analysis models. In addition, analyzed the correlation of structural characteristics and approached the application of discrete event simulation of spatial syntax theory. It is confirmed that the concept of integration of spatial syntax theory and analysis using discrete event simulation are valid as new spatial analysis methodology. Also expect that realistic and concrete predictions will be possible if discrete event simulation evolves into research for space allocation and space efficiency optimization.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 춘계학술대회
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• pp.150-155
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• 1997

Modelling and Simulation of the activation process for the myocardium is meaningful to understand special excitation conduction system in the heart and to study cardiac functions. In this paper, we propose two dimensional cellular automata model for the activation process of the myocardium and simulated by means of discrete time and discrete event algorithm. In the model, cells are classified into anatomically similar characteristic parts of heart; SA node, internodal tracks, AV node, His bundle, bundle branch and four layers of the ventricular muscle, each of which has a set of cells with preassigned properties, that is, activation time, refractory duration and conduction time between neighbor cell. Each cell in this model has state variables to represent the state of the cell and has some simple state transition rules to change values of state variables executed by state transition function. Simulation results are as follows. First, simulation of the normal and abnormal activation process for the myocardium has been done with discrete time and discrete event formalism. Next, we show that the simulation results of discrete time and discrete event cell space model is the same. Finally, we compare the simulation time of discrete event myocardium model with discrete time myocardium models and show that the discrete event myocardium model spends much less simulation time than discrete time myocardium model and conclude the discrete event simulation method Is excellent in the simulation time aspect if the interval deviation of event time is large.

• 한국시뮬레이션학회논문지
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• 제10권3호
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• pp.1-14
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• 2001

A hybrid system is defined as a mixture of continuous systems and discrete event systems. This paper first proposes a framework for hybrid systems modeling, called Hybrid Discrete Event System Specification (HDEVS) formalism. It then presents a method for simulators interoperation in which a continuous system simulator and a discrete event simulator are executed together in a cooperative manner. The formalism can specify a hybrid system in a way that a continuos system and a discrete event system are separately modeled by their own specification formalisms with a support of well-defined interface. We call such interface an A/E converter for analog-to- event conversion and an E/A converter for event-to-analog conversion. Simulators interoperation is based on the concept of pre-simulation in which simulation time for a continuous simulator is advanced in accordance with a discrete event simulator.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1134-1139
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• 2003

Tracking is a fundamental technique which is able to be applied to gesture recognition, visual surveillance, tangible agent and so forth. Especially, multiple object tracking has been extensively studied in recent years in order to perform many and more complicated tasks. In this paper, we propose a new approach of multiple object tracking which is based on discrete event. We call this system the DEMOT (Discrete Event based Multiple Object Tracking). This approach is based on the fact that a multiple object tracking can have just four situations - initiation, continuation, termination, and overlapping. Here, initiation, continuation, termination, and overlapping constitute a primary event set and this is based on the change of the number of extracted objects between a previous frame and a current frame. This system reduces computational costs and holds down the identity of all targets. We make experiments for this system with respect to the number of targets, each event, and processing period. We describe experimental results that show the successful multiple object tracking by using our 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.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.48-57
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• 2005

Discrete Event Simulation은 기존에 생산 분야에서 적용되어지는 이론중의 하나로 생산에서 발생되는 작업을 Event 기반으로 분류하고 각각의 경우를 기초로 Simulation하여 평가하는 기법이다. 철도차량의 중정비는 핵심부품의 정비를 단계별로 세분화하여 이루어지는데 틸팅차량을 포함하는 신형 철도차량의 경우 주요 정비부품이 많은 제어장치와 전자장치로 구성되어 있다 대차의 경우 많은 주요부품이 중복되어 이것을 체계적이며 효율적으로 유지 보수하는 것이 절실한 것이다. 이러한 부품의 상태를 점검하고 평가하는 것은 유지보수에 관련된 인력이 아닌 이와 관련된 분석기계일 것이고 틸팅차량의 경우 다량의 주요 부품에 대한 유지보수기계의 성능의 평가가 요구될 것이다. 본 논문은 이러한 필요성에 기초하여 작성되었다. 우선 Discrete Event Simulation의 개념을 간략히 소개하였고 Discrete Event Simulation의 5단계 알고리즘을 철도차량 유지보수기계 기반으로 수정하였다 그리고 유지보수 요구 조건에 기초하여 Simulation 알고리즘을 적용하였다. 본 논문은 Discrete Event Simulation의 이론을 이전에 적용된 사례가 없는 철도차량유지보수 분야에 소개하여 유지보수 효율의 극대화를 위한 기법을 적용하였으며 향후 철도차량 유지보수관련 기계의 성능 평가 및 적용에 있어 도움이 될 수 있는 참고 자료로 활용 가능할 것이다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.411-413
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• 1997

This paper presents the problem of fault-tolerant robust supervisory control of timed discrete event systems (DESs). First the concept of faults is quantitatively defined in timed DESs and fault tolerable event sequences are presented as a desired legal language. Given a timed DES with model uncertainty, the conditions for the existence of a supervisor which always guarantees fault tolerable event sequences embedded in the system are derived.

• 대한교통학회지
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• 제14권1호
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• pp.101-116
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• 1996

Increased attention has been paid in recent years to the need of traffic management for alleviating urban traffic congestion. This paper presents a discrete event modeling and simulation framework for analyzing the traffic flow. Traffic simulation models can be classified as being either microscopic and macroscopic models. The discrete event modeling and simulation technique can be basically employed to describe the macroscopic traffic simulation model. To do this, we have employed the System Entity Structure/Model Base (SES/MB) framework which integrates the dynamic-based formalism of simulation with the symbolic formalism of AI. The SES/MB framework supports to hierarchical, modular discrete event modeling and simulation environment. We also adopt the Symbolic DEVS (Discrete Event System Specification) to developed the automated analysis methodology for generating optimal signal light policy. Several simulation tests will demonstrates the techniques.