• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.1
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• pp.31-38
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• 2016

In this paper, the deformation-energy curves of the plastic hinges and the vessel bow, which are the major energy dissipation mechanism of a pile protective structures, were estimated, and the parametric study was performed by using those curves to apply the simplified collision model which developed in the previous study. Considered parameters were the mass of slab, the number of piles, the mass of vessel and the collision speed. As results, the difference of energy dissipation mechanism of two pile types (filled and non-filled) were revealed, and the collision behaviors of the protective structures could be tuned by the control of the inertia mass of capping slab. Therefore the simplified collision model can be used in a primary design and optimal design.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.11a
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• pp.219-221
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• 2023

첨단 디지털기술이 적용된 자율운항선박과 같이 인간의 개입을 획기적으로 줄인 첨단 시스템의 운용은, 대상 시스템의 운용 중 시스템에 영향을 미치는 다양한 변수들의 변화를 실시간으로 검토하여 안전한 시스템 운용을 위한 의사결정을 지원할 수 있는 위험도평가 방법론의 적용이 요구된다. 본 논문은, 자율운항선박의 충돌 사고 위험도를 실시간으로 분석하기 위한 위험도 모델의 개발을 목적으로, 자율운항선박 충돌 사고 시나리오에 대한 위험도분석 작업 수행 내용과 실시간 충돌 위험도를 표현하기 위하여 검토한 간략한 위험도 모델 개념들을 제시하고 있다. 위험도 모델 개발을 위하여, 먼저 자율운항선박의 항해, 통신, 비상대응 기능들을 분석하고, 기능분석 결과를 바탕으로 충돌 사고 빈도 산출을 위한 Fault Tree Analysis와 충돌 사고로 인한 영향 산출을 위한 Event Tree Analysis를 수행하였다. 또한, Fault Tree와 Event Tree의 입력값 중 외부 조건에 따라 변화하는 변수들을 식별하였고, 각 변수들에 입력값은 자율운항선박의 운항 조건에서 발생할 수 있는 가상 데이터를 만들어 사용하였으며, 식별된 각 변수들의 변화로 인한 자율운항선박 충돌 위험도 변화량을 검토하였다.

• Journal of Korean Society of Transportation
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• v.25 no.4
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• pp.69-77
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• 2007

This study presents comparison results for pedestrian accident reconstruction models representing the relationship between collision speed and horizontal distance that a body travels while falling and sliding. A set of 49 reliable pedestrian accident cases are applied to compare the existing reconstruction models. In addition, the authors investigate the effects of a set of parameters associated with the effects of the frontal shape of a vehicle on the horizontal distance a pedestrian travels while falling and sliding. It has been revealed that the length of the bumper is the most dominant factor to affect the horizontal distance of pedestrian travel after collision. Further analyses utilizing more accident data need to conducted to develop a more accurate and reliable reconstruction model.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.5
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• pp.437-450
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• 2014

In this study, we developed a methodology to determine the reference parameter for an aircraft impact induced risk assessment of nuclear power plant (NPP) using finite element impact analysis of containment building. The target structure used to develop the method of reference parameter selection is one of the typical Korean PWR type containment buildings. We composed a three-dimensional finite element model of the containment building. The concrete damaged plasticity model was used for the concrete material model. The steels in the tendon, rebar, and liner were modeled using the piecewise-linear stress-strain curves. To evaluate the correlations between structural response and each candidate parameter, we developed Riera's aircraft impact force-time history function with respect to the variation of the loading parameters, i.e., impact velocity and mass of the remaining fuel. For each force-time history, the type of aircraft is assumed to be a Boeing 767 model. The variation ranges of the impact velocity and remaining fuel percentage are 50 to 200m/s, and 30 to 90%, respectively. Four parameters, i.e., kinetic energy, total impulse, maximum impulse, and maximum force are proposed for candidates of the reference parameter. The wellness of the correlation between the reference parameter and structural responses was formulated using the coefficient of determination ($R^2$). From the results, we found that the maximum force showed the highest $R^2$ value in most responses in the materials. The simplicity and intuitiveness of the maximum force parameter are also remarkable compared to the other candidate parameters. Therefore, it can be concluded that the maximum force is the most proper candidate for the reference parameter to assess the aircraft impact induced risk of NPPs.

• Composites Research
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• v.29 no.6
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• pp.363-368
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• 2016

This study performed a nonlinear finite element crash analysis of guardrail structures using supports made of composite materials. In this study, we used a new [0/90/90/0] laminated Boron fiber composite for resisting the crash effects. Based on the improved ground-structure interaction model, appropriate ground properties to the support were determined. In particular, the complex crash mechanism of guardrails was studied using various parameters. The parametric studies are focused on the various effects of car crash on the structural performance and thickness of supports. The numerical results for various parameters are verified by comparing those using existing steel materials.

• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.3
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• pp.293-298
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• 2015

The vessel encounter data collected from the vessel trajectories in the maritime traffic situation is possible to analyze vessel collision and near-collision risk using statistical method. In this study, analyzing variables extracted from the vessel encounter data using factor analysis, we determine main factors effecting vessel collision risk from vessel encounter data. In order to calculate each factor, it used principal component analysis for factor analysis after normalization and standardization of vessel encounter variables. As a result of the factor analysis, main effect factors are summarized into the vessel approach factor and collision avoidance variance factor.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2A
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• pp.43-49
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• 2011

In this study, to analyze the collision behaviors of the bridge super-structure and the vessel which the collision point is located far from its rotation center such as bridge of a vessel and equipments on a barge, the simplified collision model was proposed. The model was configured to denote the mass, stiffness and the nonlinear behaviors of the bridge and the vessel. The nonlinear equation of motions of the proposed model were numerically solved by 4th order Runge-Kutta method. The parametric studies were performed for various collision conditions by the standardized Korean barge vessel in term of barge width, and its effects to the maximum collision load of bridge were analyzed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.1
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• pp.25-33
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• 2020

In this study, parametric analyses are performed using the coupled Eulerian-Lagrangian scheme for the collision behaviors of a vessel and an underwater slope that constitutes part of an artificial protective island. The vessel parameters considered in the analysis are bow angle, stem angle, draft, and impact velocity. The gradient of the slope, the friction coefficient between the bow and the slope, and soil strength are considered as parameters of the slope. For each parameter, the dissipated collision energy and the collision force are estimated from the behavior of the vessel, and the energy dissipation mechanism is identified in terms of the ground deformation. The collision force is assumed as an exponential function, and the effects of the parameters are estimated. As a result, only two parameters, the gradient of the slope and the friction coefficient between the vessel and the soil, can affect the exponential coefficient of the function. The dissipated energy by the soil can thus be estimated adequately. The relationship between the volume of the soil pushed out by the bow and the dissipated collision energy is estimated as a linear function. This relationship is independent of the magnitude of the collision energy, and affected more by the friction coefficient and the soil strength than by the parameters of the vessel.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.11a
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• pp.264-264
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• 2019

The purpose of this paper is to establish development concepts for a novel collision avoidance system with preventing function of navigator's human error (Hu-CAS) in ship control behaviors. Hu-CAS consists of four modules: 1) collision risk assessment module to estimate collision priority between the ship and objects, 2) decision-making module to decide collision risk levels, 3) parameter estimation module needed in the ship control to avoid collisions and 4) control system to control the rudder angle and speed. Hu-CAS, proposed in this paper, can provide a novel system substitution current Autopilot and/or a CAS be teen manned vessel and Autonomous ship in a future.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2001.12a
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• pp.121-124
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• 2001

충돌회피 시스템은 선박의 안전 항해에 중요한 역할을 한다. 충돌회피 시스템은 선박이 장애물을 만났을 때 영역전문가인 항해사를 대신하여 피항 행위를 하도륵 지시하는 시스템으로 자선에서 이루어지는 해상 장애물들에 대한 피항 시 그 판단 기준을 각 장애물에 대한 충돌위험도에 둔다. 따라서 본 연구에서는 선박의 충돌회피 시스템의 보다 안전한 충돌회피를 도모하기 위해 충돌회피를 위한 충돌위험도 결정 시스템을 제안한다. 충돌위험도 결정 시스템은 장애물 모델링과 장애물의 충돌위험도 결정의 두 부분으로 구성된다. 장애물 모델링은 선박의 센서에서 나오는 저수준의 자료를 지능형 선박의 타 시스템에서 이용하기 쉽도록 구하는 과정이다. 충돌위험도 결정 시스템의 출력으로 산출되는 충돌위험도는 충돌회피 시스템의 피항 행위 결정에 정보로 사용된다. 본 연구에서는 DCPA와 TCPA를 이용한 기존의 기법에 VCD의 개념을 추가한 새로운 충돌위험도 결정 기법을 제안한다. 입력변수가 되는 DCPA, TCPA, VCD의 퍼지 소속함수를 산출하고 이를 기반으로 퍼지 추론을 이용하여 세부적인 충돌위험도를 결정한다. 본 연구에서 제안하는 기법은 기존의 DCPA와 TCPA만으로 충돌위험도를 결정한 경우보다 상세한 충돌위험도 결정이 가능하다는 장점과 국제해상충돌예방규칙의 내용이 적용되었다는 장점을 지닌다. 제안된 기법은 DCPA와 TCPA 만으로 충돌위험도를 결정한 기법과 비교.평가하여 성능을 검증한다.