• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.4
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• pp.61-70
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• 2006

This paper is to describe LYNX-ESM Simulation System to simulate for EW operating environment analysis and system performance verification of LYNX-ESM system using Discrete Event Simulation(DEVS) Methodology. This system consists of 3 PC with TCP/IP network. Each PC is loaded with Modeling & Simulation program based DEVS. Each connected program conducts EW simulation. As a result, we analyze the operating environment of the maritime EW threat, simulate the EW threat discrimination and geolocation capability, and estimate the LYNX-ESM system effectiveness before real LYNX-ESM system development.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06b
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• pp.418-421
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• 2007

컴퓨터 시스템의 디지털화가 진행됨에 따라 많은 시스템들의 거동이 이산적인 속성과 연속적인 속성이 혼재되어 있다. 이러한 시스템의 특성을 정확히 반영하기 위해서는 모델링 단계부터 이산적인 속성과 연속적인 속성을 반영할 수 있는 하이브리드 오토마타 기반의 모델링이 요구 되어 진다. 대표적으로 자동차, 항공 우주, 원자력 등 제어 시스템 분야를 예로 들 수 있다. 이런 분야는 특히 안정성 및 실시간성이 매우 중요하여 명세로부터 구현에 이르기까지 검증과 확인의 단계가 매우 중요하다. 또한 개발 단계에서 뿐만이 아니라 시스템의 운영 단계에서도 지속적인 모니터링이 필요하다. 본 논문에서는 실시간 시스템의 운영중에 하이브리드 오토마타 기반의 명세와 구현의 일치성 여부를 확인 할 수 있는 모니터링 기법에 관해 연구하였다.

• Journal of KSNVE
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• v.7 no.1
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• pp.135-142
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• 1997

This paper presents a digital modeling technique of the distributed system. The basic idea of the proposed technique is to discretize a continuous system with respect to the spatial coordinates using bilinear method. The response of the discretized system is analyzed by Laplace transform and z-transform. The computational results in torsional shaft and Timoshenko beam using the proposed technique are compared with the exact solutions and the results of finite element method.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.6
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• pp.156-164
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• 2000

In this study, a discrete time model for a simplified front wheel suspension system which has nonlinear dampling and stiffness property is introduced. The model is estimated from the discrete data which are generated based on the real car parameter. The performance of the proposed method is evaluated through numerical simulation, and the simulation results show that the proposed method can estimate the nonlinear behavior of the suspension system very well.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04a
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• pp.800-802
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• 2003

이 논문에서는 웹 기반의 하이퍼미디어 교육시스템에서 이산 확률 분포 함수와 사용자 프로파일 기반의 동적 적응 모델을 제안하였다. 이 모델은 응용 영역을 동적 적응 객체의 가중치 방향성 그래프로 표현하며 사용자 행위를 이산 확률 함수를 동적으로 구축하는 접근 방식을 이용하여 모델링 한다. 제안한 확률적 해석은 웹 미디어 구조에서 사용자의 탐색 행위를 추적하여 사용자 행위에 대한 잠재적 속성을 나타내는데 사용될 수 있다. 이러한 접근 방식은 사용자에게 가장 알맞은 프로파일을 동적으로 할당할 수 있다.

• School Mathematics
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• v.7 no.1
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• pp.77-101
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• 2005

This study is a discussion of the teaching and learning of discrete mathematics in school mathematics. In this study, we summarized the importance of discrete mathematics m school mathematics. And we examined instruction methods of discrete mathematics expressed in the 7th mathematics curriculum. On the basis of analysis for teaching cases in previous studies, we proposed four suggestions to organize discrete mathematics classroom. That is as follows. First, discrete mathematics needs to be introduced as a mathematical modeling of real-world problem. Second, algorithm learning in discrete mathematics have to be accomplished with computer experiments. Third, when we solve a problem with discrete data, we need to consider discrete property of given data. Forth, discrete mathematics class must be full of investigation and discussion among students. In each suggestion, we dealt with detailed examples including educational ideas in order to helping mathematics teacher orgainzing discrete mathematics classroom.

• Journal of Digital Convergence
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• v.11 no.8
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• pp.205-212
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• 2013

In this paper, we present a procedural modeling algorithms to create Korean traditional stone fence using the fractal subdivision. The main process of the algorithm is to get the next step mesh by subdividing each triangle in the previous step triangular mesh. This process is repeated recursively. Dividing each triangle into four sub-triangles after choosing a random point on each side of the triangle and moving each vertices in the normal direction with random perturbations make the bumpy appearance of stone fences. In each step we remove flat vertices which does not influence the shape of the stone. The discrete curvature determines the flatness of a vertex. New triangles whose vertices are the vertices around the removed vertex are added to make a triangular mesh.

• Journal of the Korea Society for Simulation
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• v.21 no.2
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• pp.19-30
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• 2012

In recent decades, it has been known that the Discrete Event System Specification, or DEVS, formalism provides sound semantics to design a modular and hierarchical model of a discrete event system. In spite of this benefit, practitioners have difficulties in applying the semantics to real-world systems modeling because DEVS needs to specify a large size of sets of events and/or states in an unstructured form. To resolve the difficulties, this paper proposes an extension of the DEVS formalism, called the Structured DEVS formalism, with an associated graphical representation, called the DEVS diagram, by means of structural representation of such sets based on closure property of set theory. The proposed formalism is proved to be equivalent to the original DEVS formalism in their model specification, yet the new formalism specifies sets in a structured form with a concept of phases, variables and ports. A simplified example of the structured DEVS with the DEVS diagram shows the effectiveness of the proposed formalism which can be easily implemented in an objected-oriented simulation environment.

• The Journal of Korean Association of Computer Education
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• v.9 no.1
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• pp.89-95
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• 2006

The local geometric properties such as curvatures and normal vectors play important roles for analyzing the local shape of objects in the fields of computer graphics and computer vision. The result of the geometric operations such as mesh simplification and mesh smoothing is dependent on how to compute the curvatures of meshes because there is no exact mathematical definition of curvature at vertices on 3D meshes. Therefore, In this paper, we indicate the fatal error in computing the sectional curvatures of the most previous discrete curvature estimations. Moreover, we present a discrete curvature estimation to overcome the error, which is based on the parabola interpolation and the geometric properties of Bezier curves. Therefore, We can well distinguish between the sharp vertices and the flat ones, so our method may be applied to a variety of geometric operations.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.04a
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• pp.523-526
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• 2010

주어진 경계선에 대해 비누막이 생성하는 표면 모델링 및 시간에 따른 변형 시뮬레이션은 컴퓨터 그래픽스 응용 프로그램의 한 분야이다. 이 문제에 대한 이전의 연구들은 주로 기하적인 방법들을 이용하였기 때문에 물리적으로 정확한 변형을 다루지 못하였다. 본 연구에서는 정확한 기하를 바탕으로 물리기반 변형을 다루기 위해 이산미분기하학으로부터 비누막의 동적인 모델을 제안한다. 우선, 비누 성분의 물리적인 특성들을 고려한 에너지 모델을 정의하고, 이를 이산 영역에서 나타내기 위해 이산미분기하 및 이산화 기법들을 이용한다. 제안하는 모델은 평형 상태에서의 비누막 형상뿐만 아니라 외력에 대한 표면의 변형까지 정확하게 나타내며, 실시간 시뮬레이션이 가능하여 게임, 애니메이션 목적으로 활용될 수 있다.