• International Journal of Highway Engineering
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• v.9 no.3
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• pp.39-50
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• 2007

Barrier VII program is normally used for the design of flexible barrier, but if modelled properly it can be used for the analysis of vehicle impact to small sign posts. In this paper sign post is shown to be modelled as flexible barrier by combining beam and column elements at each beam node. Simulations with the Barrier VII program have been made for 7 impact cases composed of sign posts of circular and H section with rigidly connected support and breakaway support system. The impact speed used for the simulation ranged from 30km/h to 110km/h. The study shows that in the vehicle impacts to a circular sign post with high speed, the large deflection and high inertia force causes the sign plate to hit the windshield leading to a hazard to the occupants. It is also shown that impact to H section post results in small deflection of the post and abrupt velocity change and high deceleration of the impact vehicle causing severe damage to both the vehicle and occupants. Simulation study also shows that breakaway support system eliminates the potential danger of the vehicle impact to the rigidly connected small sign posts by reducing deflection of the post, abrupt change in velocity and deceleration level.

• Proceedings of the KOR-KST Conference
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• 1998.10b
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• pp.409-409
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• 1998

본 연구는 운전자 특성 및 교통사고 발생유형에 따른 사고 심각도(Severity)를 분석함으로써 교통사고를 유발키 쉬운 운전자 집단과 사고 발생시 위험도가 높은 사고유형을 규명하고자 하였다. 교통사고 위험집단 분석을 위한 운전자 특성은 성별, 차종, 연령 등을 대상으로 하였으며, 사고유형별 심각도 분석은 사고유형을 여덟 가지로 분류하고, 결과의 신뢰성 확보를 위하여 안전벨트 착용여부를 추가하여 상해정도와의 관계를 비교하였다. 로그-선형 모형 및 로짓 모형을 사용하여 카테고리 자료를 분석하였으며, 그 결과 위험집단 분석에서는 '20세 미만의 이륜차 운전자', '41세에서 50세까지의 택시운전자'가 가장 위험한 것으로, 또한 남자보다는 여자가 승용차, 택시, 이륜차 등에 관계되었을 때 위험한 것으로 조사되었다. 사고유형과 심각도와의 관계에서는 정면충돌 사고와 앞지르기 시 우회전시 사고가 기여위험도(Odds Multiplier)가 매우 높아 부상 또는 사망사고와 연계될 가능성이 큰 것으로 나타났다. 따라서 교통사고의 예방과 사고발생시의 심각도 경감을 위해서는 교통사고 취약계층으로 분석된 위험집단에 대한 교통안전 교육 및 홍보가 강화되어야 하고, 정면충돌 사고와 앞지르기 시 우회전시 발생하는 사고를 줄일 수 있는 방안이 연구되어야 할 것이다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.05a
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• pp.167-168
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• 2023

가상현실 기술은 다양한 유형으로 발전하고 있다. 해양경찰은 함정 조함 교육을 위해 두 가지 가상현실 환경에서 실습이 진행 중이다. 이 연구는 두 가지 가상 현실 환경에서 조함 교육효과가 어떻게 나타나는지 알기 위해 항해 위험성을 평가하고 분석하였다. 실물형은 데스크톱형보다 최근접거리가 더 길고, 대각도 타 사용 시간과 비상인지 시간이 더 길게 나타났다. 향후 해양경찰 함정 교육을 위한 최적의 가상현실 환경을 구축하고 확장하는데 기초자료로 활용할 예정이다.

• Journal of Navigation and Port Research
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• v.39 no.6
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• pp.493-498
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• 2015

When VTSOs(Vessel Traffic Service Operators) determine the degree of collision risk of two vessels, they consider comprehensively information about each vessel's course, speed, DCPA, TCPA and encountering situation. In this study, we proposed an algorithm in which two relative bearings as information about two vessel's encountering situation are used to evaluate the degree of collision risk. In order to verify whether the proposed algorithm is reasonable, we set twenty encountering situations and conducted a survey of collision risk on fifty three VTSOs about those situations. By comparing the degrees of collision risk with the proposed algorithm to the results of the survey, we found that relative bearing at CPA is very important factor for VTSO to recognize the level of collision risk when two vessels are in encountering situation.

• Journal of Navigation and Port Research
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• v.28 no.6
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• pp.475-480
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• 2004

Author presented some study with regard to “automatic control for ship collision avoidance system” before. Those papers are to deal with unsolved problem,; in the previous study. In this paper, two issues relating to ship collision avoidance were investigated. One is to suggest a new algorithm of avoidance of a group ship. This algorithm is useful when a ship takes avoiding action for a group fish boats and a group of merchant vessels. In the stage of taking avoidance action, newly-developed algorithm was used. the other is to develop a unified model of collision risk. Generally collision risk changes according to various type of encounters. The new model is to take into account of these situations. The above-mentioned algorithm and model were verified through simulation under various encounters between ships.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.2
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• pp.238-246
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• 2021

Collision of small vessels such as fishing boats cause great personal injury. Prior to this study, the collision prevention algorithm was developed to assess the collision risk and make the collision alarm. However, a service provided for safety, such as a collision warning, not only prevents risks, but also requires a certain degree of user satisfaction to function effectively. In this study, the collision prevention algorithm for small vessels was improved to be more practical, and the effects of the improvement were confirmed by applying the algorithm. A survey conducted on the users of the collision warning service confirmed the user requirements for improving the accuracy of the collision warning system and reducing the volume and number of alarms. Accordingly, the algorithm was improved for user satisfaction, and the actual vessel experiment was performed applying the improved algorithm in an actual maritime environment. As a result, the frequency of alarm occurrence decreased compared to former algorithm, but the alarm was relatively steadily generated in dangerous situations. It was analyzed that the accuracy and practicality of the collision alarm were improved. If the practicality and reliability of the improved algorithm are verified in the further study, it will be able to effectively contribute to the prevention of collisions of small vessels.

• Journal of Navigation and Port Research
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• v.43 no.1
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• pp.57-63
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• 2019

It is time to study safety improvement on container terminals to maintain a high-quality service to customers' productivity and safety. The data analyzed was of the past 3 years accidents data from a container terminal in the Busan port. I especially tried to found out the equipment that had the highest number of accidents and what the main causes were. This study suggests the top hazards identified in the container terminal using risk assessment, Moreover, it seeks control measurements to prevent hazards by bowtie methodology.

• Aerospace Engineering and Technology
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• v.7 no.2
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• pp.1-10
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• 2008

The Bird strike to small aircraft has not been an issue because of it's low speed and usage as a private aircraft. So, the compliance of the bird strike regulation is limited to large fixed-wing aircraft such as the commuter category in FAR Part 23 and the civil aircraft in FAR Part 25, generally. However, the forecast of dramatic increasing of VLJ(Very Light Jet) and (light time of general aviation due to Air-taxi for the point to point transportation, would rise up the need of bird strike regulations and a safety enhancement in normal and utility categorized aircraft. In this study, the safety enhancement concept using a crushable foam for the bird strike to small aircraft wing leading edge, and the evaluation about the safety of the bird strike to small aircraft are proposed using the explicit finite element analysis.

• Proceedings of KOSOMES biannual meeting
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• 2001.10a
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• pp.81-97
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• 2001

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.4
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• pp.483-491
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• 2021

The identification of regional collision risks in water areas is significant for the safety of navigation. This paper introduces a new method of collision risk assessment that incorporates a clustering method based on the distance factor - hierarchical clustering - and uses real-time data in case of several surrounding vessels, group methodology and preliminary assessment to classify vessels and evaluate the basis of collision risk evaluation (called HCAAP processing). The vessels are clustered using the hierarchical program to obtain clusters of encounter vessels and are combined with the preliminary assessment to filter relatively safe vessels. Subsequently, the distance at the closest point of approach (DCPA) and time to the closest point of approach (TCPA) between encounter vessels within each cluster are calculated to obtain the relation and comparison with the collision risk index (CRI). The mathematical relationship of CRI for each cluster of encounter vessels with DCPA and TCPA is constructed using a negative exponential function. Operators can easily evaluate the safety of all vessels navigating in the defined area using the calculated CRI. Therefore, this framework can improve the safety and security of vessel traffic transportation and reduce the loss of life and property. To illustrate the effectiveness of the framework proposed, an experimental case study was conducted within the coastal waters of Mokpo, Korea. The results demonstrated that the framework was effective and efficient in detecting and ranking collision risk indexes between encounter vessels within each cluster, which allowed an automatic risk prioritization of encounter vessels for further investigation by operators.