• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3A
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• pp.323-330
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• 2008

The ship collision analysis of steel pile group as protection system of bridge in navigable waterways was performed to analyze the structural characteristics of protective structure during ship collision. The analysis encompassed finite element modeling of ship and pile, modeling of material non-linearity, hard impact analysis, displacement-based analysis and soft impact analysis for collision scenarios. Through the analysis of hard impact with a rigid wall, impact load for each collision type of ship bow was estimated. In the displacement-based analysis the estimate of energy which protection system can absorb within its maximum horizontal clearance so as to secure bridge pier from vessel contact during collision was performed. Soft impact analysis for various collision scenarios was conducted and the collision behaviors of vessel and pile-supported protection system were reviewed for the design of protection system. The understanding of the energy dissipation mechanism of pile supported structure and colliding vessel would give us the optimized design of protective structure.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.1
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• pp.78-85
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• 2012

Space debris is the collection of objects in orbit around the Earth that were created by humans but no longer serve any useful purpose. Since the beginning of spacecraft launch in 1957, the number of space debris has been increasing. According to USSTRATCOM, the number of space debris which were bigger than 10 cm is more than 15,000. Recently there were two critical events: One is that China shot down their satellite using missile and the other is that two satellite, United States's Iridium 33 and Russia's Cosmos 2251, collided with each other. Thanks to these events, Space environment in which KOMPSAT-2 operates has become severer. This paper presents the analysis of the number of space debris which are close to KOMPSAT-2 and the maximum conjunction probability via minimum range. Especially, this paper makes it possible to continuously monitor the space debris that is possible to hit KOMPSAT-2 through the identification and analysis.

• Journal of Navigation and Port Research
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• v.26 no.3
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• pp.275-280
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• 2002

Vessel collision accidents have been investigated by means of questioning the persons involved and plotting manually the stated situation. But the repetitive plotting by hand can cause the investigator or to make some errors, and it can be connected to a wrong judgement. In this paper, we proposed a simulator for reconstructing and analyzing vessel collision accidents at sea, where the given situation is plotted automatically on it. We verified the validity of the system by applying it to some collision accidents.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.11a
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• pp.82-83
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• 2022

국제해상충돌예방규칙(COLREGs)에 관한 협약은 해상에서 발생하는 충돌사고를 방지하기 위한 규칙으로 구성되어 있으며, Seaman(선원)의 Qualitative Rule(질적 규칙)과 Ordinary practice(통상적인 관행)에 기초하고 있다. MASS의 출현으로 인하여 질적 규칙과 관행으로 인하여 COLREG를 기반으로 한 항법 해석의 기준의 다름이 발생하였고, 기준의 차이로 인해 충돌 상황에 대한 항법 해석의 모호성문제가 발생하고 있다. 따라서 본 연구는 COLREG의 항법 해석의 모호성을 규명하여 유인과 무인 사이의 충돌회피 상황을 명확히 하는 것을 목적으로 한다. COLREG를 기반으로 한 충돌 상황의 모호성을 식별하기 위해 실제 항해사를 대상으로 충돌 회피 상황에 대한 인식을 조사하고, 정면 및 횡단, 횡단 및 추월 상황을 기반으로 조사 결과를 분석하였다. 분석 결과, 응답자들은 008°에서 마주치는 선박에 대해서 정면 또는 횡단 상황 항법 규칙을 적용해야 하는지, 160°에서 다가오는 선박에 대해서 추월 또는 횡단 상황을 적용해야 하는지에 대해 확신하지 못하는 것으로 나타났다. 이러한 결과는 이러한 모호성의 증가와 함께 충돌회피상황의 수동적 행동보다 능동적인 행동을 취함으로써 선원에 의한 충돌위험을 회피하려는 경향이 더 강해짐을 나타낸다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2017.01a
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• pp.181-182
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• 2017

게임에서 캐릭터와 몬스터 간, 캐릭터와 캐릭터 간, 피격처리 등을 위해서는 충돌처리가 필요하다. 본 논문에서는 Unity3D 엔진에서 지원하는 충돌처리 방법을 비교분석하였다. Unity3D 엔진에서 지원하는 충돌처리 방법은 Collider 방식과 Raycast 방식이 있으며, Collider 방식은 정적이거나 속도가 아주 느린 오브젝트에 사용하고, Raycast방식은 속도가 빠른 투사체를 구현하는데 적합하다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.7
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• pp.801-809
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• 2017

The purpose of this study is to contribute to the prevention of ship collisions by investigating real ship collision cases and statistically analyzing causes of human error for captains and Officers of the Watch (OOW). This study encompassed a total of 109 cases for 218 vessels, which were suitable for the analysis of ship accidents between merchant ships or merchant ships and fishing boats over the 7 years from 2010 to 2016. Data was collected while classifying vessels according to type, Give-way and Stand-on vessels, along with the cause of human error. Factors causing human error were identified after focusing on the cause of each collision given by the OOW ; frequency and cross tabulation analyses were conducted using SPSS, a statistical analysis tool. As a result, the main causes of human error by an OOW in a ship collision situation were that lookout was neglected in a Give-way vessel including radar surveillance (74.3 %) or continuous observation of an opponent vessel was carried out (17.4 %). A major factor for Stand-on vessels was failure to act to avoid collision with another vessel (63.3 %). In particular, most neglect for lookout type merchant ships occurred after the opponent ship was first observed, and a common cause of lookout neglect and neglect of duty was a focus on other tasks during navigational watch time.

• 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.36 no.6
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• pp.365-370
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• 2023

This paper presents a particle-structure collision model for topology optimization, which requires sensitivity analysis. Therefore, a new model that incorporates sensitivity analysis is needed. The proposed particle-structure collision model conducts sensitivity analysis for topology optimization. To evaluate the accuracy of the proposed model, it was applied to a simplified one-dimensional collision problem. Optimization of the final positions of particles using topology optimization through this model confirmed the suitability of the proposed approach. These results demonstrate that it is possible to consider particle-structure collision in topology optimization.

• Journal of the Korean Institute of Intelligent Systems
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• v.27 no.2
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• pp.113-118
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• 2017

Various studies on the method of ship collision risk assessment for alarm have been reported constantly, and the result of the studies is applied to navigation devices. However, it is known that navigators ignore or turn off frequent alarms from the devices of predicting collision risk, because they may avoid collisions in the most of situations. In oder to make the prediction of ship collision risk more useful, it is necessary to consider the customary actions of ship collision avoidance. This paper proposes a system of analyzing collision avoidance measures of ships according to the types of encounter and managing the avoidance history of each ship. The core module of the system is designed as a neuro-fuzzy based inference system, and the test of the module validates the proposed system.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.11a
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• pp.89-94
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• 2004

Up to now a lot of the study on ship collision avoidance systems has proceeded actively. However the frequency of ship collision accidents didn't decreased. If there is collision risk in close quarters situation none the less manouvering ship for collision avoidance according to the system, only use of TCPA and DCPA as input factor for collision risk decision is not useful to avoiding collision action. For the recent 5 years by the analysis of first observation distance about approaching ship in domestic collision accidents, nearly $45\%$ of accidents is close first observation less than 2 miles. Therefor it is essential part for safety navigations to study for collision avoidance action in close encounter. In this paper, as foundation study of supporting collision avoidance manoeuvring for navigators, we proposed ship collision avoidance support model in close quarters situation through analysis of collision accidents for effective getting rid of the causes.