• Journal of the Computational Structural Engineering Institute of Korea
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• v.14 no.4
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• pp.413-422
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• 2001

In this study, the effect of hydrodynamic masses is investigated in the dynamic characteristics and earthquake response analyses of the submerged HANARO flow tubes. First, the consistent hydrodynamic masses of the surrounding water are obtained by finite element method. Then, modal analyses and response spectrum analyses are performed and verified by comparing the results with those measured from an experiment. Arbitrary cross-sections of submerged structures and boundary conditions of the surrounding fluid can be considered by using the general benefits of a finite element method comparing with the conventional analytical methods. Practical criteria based on parametric studies are proposed to evaluate the dynamic characteristics of HANARO flow tubes including the hydrodynamic masses.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.567-569
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• 2011

플러그인 프레임워크는 구성요소 간 높은 종속관계 및 낮은 유연성을 해결하고자 개발된 S/W 기반요소로서, 프레임워크를 구성하는 컴포넌트를 플러그인으로 제공하여 구성요소의 추가 및 변경이 동적으로 이루어지게 한다. 이를 통해 소프트웨어 구성을 위해 필요한 컴포넌트들이 동적으로 추가 혹은 변경하여 소프트웨어를 구현 가능하게 되어 소프트웨어의 확장성 및 재사용성을 증대시킨다. 하지만, 플러그인 프레임워크 기반의 소프트웨어 개발 과정은 낮은 종속관계의 구성요소가 결합되어 이뤄지는 만큼, 개별 구성요소의 인터페이스 및 구성요소 간 통합을 사전에 검증할 수 있는 통합시험환경에 대한 필요성이 제기된다. 이에 본 논문은, 동적 구성요소의 개별 인터페이스 검증 및 구성요소 간 통합검증이 가능한 플러그인 프레임워크 기반에서의 통합시험도구에 대해 제안하고, 이에 대한 개략설계내용을 기술한다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.35 no.5
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• pp.95-101
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• 2023

Recent persistent coastal developments have expanded recreational areas and enhanced accessibility. However, this growth has also led to a rise in safety incidents. These accident factors can be divided into human-made and natural types. The latter is comprised of dynamic factors like waves, tides, sea fogs, and winds. While institutions like the Korea Meteorological Administration and the Korea Hydrographic and Oceanographic Agency already offer data on these dynamic factors, the resolution is often insufficient for a precise assessment of localized risks. In this study, to overcome these limitations, we utilized the dynamic information from existing open systems to construct a high-resolution numerical simulation. Through this, we developed an automated module to predict dynamic factors in localized coastal activity areas. Particularly during the module's construction, we compared and reviewed the numerical prediction results for waves with observed wave heights.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.13 no.4
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• pp.437-448
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• 2000

In this study, a numerical analysis method for soil-pile interaction in frequency domain problem is presented. The total soil-pile interaction system is divided into two parts so called near field and far field. In the near field, beam elements are used lot a pile and plain strain finite elements for soil. In the far field, dynamic fundamental solution for multi-layered half planes based on boundary element formulation is adopted lot soil. These two fields are coupled using FE-BE coupling technique. In order to verify the proposed soil-pile interaction analysis, the dynamic responses of pile on multi-layered half planes are simulated and the results are compared with the experimental results. Also, various numerical analyses of piles considering different conditions of soil-pile interaction system are performed to examine the dynamic behavior of the system. It has been found that the developed method which satisfies the radiation conditions of multi-layered half planes can be applied to various structure systems effectively in frequency domain.

• The Journal of the Korea Contents Association
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• v.22 no.6
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• pp.56-68
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• 2022

Recently, as the demand for real-time processing increases, studies on a dynamic graph that changes over time has been actively done. There is a connected components processing algorithm as one of the algorithms for analyzing dynamic graphs. GPUs are suitable for large-scale graph calculations due to their high memory bandwidth and computational performance. However, when computing the connected components of a dynamic graph using the GPU, frequent data exchange occurs between the CPU and the GPU during real graph processing due to the limited memory of the GPU. The proposed scheme utilizes the Weighted-Quick-Union algorithm to process large-scale graphs on the GPU. It supports fast connected components computation by applying the size to the connected component label. It computes the connected component by determining the parts to be recalculated and minimizing the data to be transmitted to the GPU. In addition, we propose a processing structure in which the GPU and the CPU execute asynchronously to reduce the data transfer time between GPU and CPU. We show the excellence of the proposed scheme through performance evaluation using real dataset.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.1
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• pp.23-28
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• 2010

Reliable dynamic analysis is essential in order to properly maintain structures so that structural hazards may be minimized. The finite element method (FEM) is proven to be an affective approximate method of structural analysis if proper element types and meshes are chosen. When the method is applied to dynamics analyzed in time domain, the meshes may need to be modified at each time step. As many meshes need to be generated, adaptive mesh generation schemes have become an important part in complex time domain dynamic finite element analyses of structures. In this paper, an adaptive mesh generation scheme for dynamic finite element analyses of structures is described. The concept of representative strain value is used for error estimates and the refinements of meshes use combinations of the h-method (node movement) and the r-method (element division). The validity of the scheme is shown through a cantilever beam example under a concentrated load with varying values. The example shows reasonable accuracy and efficient computing time. Furthermore, the study shows the potential for the scheme's effective use in complex structural dynamic problems such as those under seismic or erratic wind loads.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.16 no.2
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• pp.207-216
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• 2003

In this paper, the finite element method for the elastodynamic axisymmetric fracture analysis is presented in matrix form through the application of the Galerkin method to the time integral equations of motion with no inertia forces. Isoparametric quadratic quadrilateral element and triangular crack tip singular elements with one-quarter node are used in the mesh division of the finite element model. To show the validity and accuracy of the proposed method, the infinite elastic medium with the penny shaped crack is solved first and compared with the analytical solution and the numerical results by the finite difference method and the boundary element method existing in the published literatures, and then the dynamic stress intensity factors of solid and hollow cylinders of finite dimensions haying penny-shaped cracks and internal and external circumferential tracks are computed in detail.

• 한국IT서비스학회:학술대회논문집
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• 2006.11a
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• pp.177-184
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• 2006

시스템의 동적 요소를 기술하고 분석하기 위해 C&C view 아키텍처를 주로 사용하지만 시스템의 실행 순서나 상태에 대한 정보가 부족하기 때문에 단지 C&C view 아키텍처로만 시스템의 동적 요소를 분석하기가 어렵다. FSP model은 시스템의 동작을 표현하기 위한 모델링 언어로써 시스템의 동작을 모델링 할 뿐만 아니라 LTSA라는 FSP 검증 툴을 이용하여 시스템의 특성을 자동으로 파악하기에도 용이한 특성을 가지고 있어 시스템 동적 요소 분석에 도움을 준다. 하지만 관련 정보를 얻기 어려워 FSP model을 구현하는데 어려움이 있다. 이 논문은 C&C view 아키텍처와 요구 사항(Use Case Scenario 혹은 Sequence diagram)을 근간으로 시스템의 동적 요소를 FSP로 모델링 하는 방법을 정의한다. 또한 LTSA 툴을 이용하여 자동적으로 시스템의 특성을 검증할 수 있고, 이를 통해 시스템 구현 전에 시스템의 에러를 찾아내고 해결하는 도움을 줄 수 있다. C&C view 아키텍처는 시스템의 컴포넌트와 커넥터에 대한 정보를 제공하여 주고 요구 사항은 소프트웨어 시스템의 행동에 대한 정보를 제공하여 줄 수 있다. 만약 우리가 컴포넌트와 커넥터에 대한 정보가 있고 시스템 동적 요소에 대해 알고 있다면 우리는 이것을 기반으로 메시지 흐름도를 구현할 수 있다. 메시지 흐름도는 Harel, Kugler 와 Pnueli에 의해 개발된 Synthesized 알고리즘을 이용하여 Statechart로 만들어지고 이것은 바로 FSP model로 변환될 수 있다. 우리가 소프트웨어 시스템에 대한 FSP model을 가지고 있다면 이것을 기반으로 시스템 행동 특성을 체크할 수 있으며 이는 향후 발생할 수 있는 결함을 미리 찾아내는데 유용한 도움이 될 수 있다. 우리는 간단한 예제를 통해 본 논문의 이론을 수립하였으며 이를 기반으로 실제 어플리케이션에 적용하여 그 효용성을 검증하였다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.192-195
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• 2010

본 논문에서는 해상 크레인과 중량물의 동적 거동을 시뮬레이션하기 위해, 유한 요소 정식화(finite element formulation)를 이용하여 해상 크레인의 붐(boom)을 탄성체로 모델링 하였다. 붐은 3차원 탄성 빔(beam) 요소로 가정하고, 각 요소의 변형에 의한 변위는 형상 함수(shape function)과 절점 좌표(nodal coordinate)를 이용하여 정의하였다. 변형 변위를 이용하여 탄성 붐의 강성 행렬(stiffnes matrix)을 유도하고, 탄성 변위를 포함하는 위치 벡터를 이용하여 질량 행렬을 유도한다. 해상 크레인과 중량물로 이루어진 운동 방정식에 탄성 붐을 포함하여 유연 다물체계(flexible multibody system) 운동 방정식을 구성한다. 외력으로는 선박 유체정역학적 힘, 유체동역학적 힘, wire rope의 장력, 중력 그리고 계류력(mooring force)이 고려되었다. 먼저 요소의 개수를 변경하며 탄성 붐의 동적 거동을 시뮬레이션 하여, 유한 요소 정식화를 이용한 모델링의 타당성을 검증하였다. 그리고 해상 크레인과 중량물의 동적 거동 시뮬레이션에 탄성 붐 모델을 적용하였다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.3
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• pp.259-265
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• 2009

This paper studies the Element Connectivity Parameterization Method(ECP method) for topology optimization considering dynamic compliance. The previous element density based topology optimization method interpolates Young's modulus with respect to design variables defined in each element for topology optimization. Despite its various applications, these element density based methods suffer from numerical instabilities for nonlinear structure and multiphysics systems. To resolve these instabilities, recently a new numerical method called the Element Connectivity Parameterization(ECP) Method was proposed. Unlike the existing design methods, the ECP method optimizes the connectivities among plane or solid elements and it shows some advantages in topology optimization for both nonlinear structure and multiphysics systems. In this study, the method was expanded for topology optimization for the dynamic compliance by developing a way to model the mass matrix in the framework of the ECP method.