• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.3B
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• pp.248-253
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• 2011

Collision avoidance algorithm of vessels have been studied to avoid collision and grounding of a vessel due to human error. In this paper, We propose a collision avoidance algorithm using bayesian estimation theory for safety sailing and reduced risk of collision accident. We calculate collision risk for efficient collision avoidance using bayesian algorithm and determined the safest and most effective collision risk is predicted by using re-planned with re-evaluated collision risk in the future(t=t'). Others ship position is assumed to be informed from AIS. Experimental results show that we estimate the safest and most effective collision risk.

• International Journal of Naval Architecture and Ocean Engineering
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• v.13 no.1
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• pp.340-350
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• 2021

This paper proposes a decision support model for USVs to improve the accuracy of collision avoidance decision-making. It is formed by Navigation Safety Domain (NSD) and domain-based Collision Risk Index (CRI), capable of determining the collision stage and risk between multiple ships. The NSD is composed of a warning domain and a forbidden domain, which is constructed under the constraints of COLREGs (International Regulations for Preventing Collisions at Sea). The proposed domain based CRI takes the radius of NSD in various encounter situations as threshold parameters. It is found that the value of collision risk in any directions can be calculated, including actual value and risk threshold. A catamaran USV and 6 given vessels are taken as study objects to validate the proposed model. It is found that the judgment of collision stage is accurate and the azimuth range of risk exists can be detected, hence the ships can take direct and effective collision avoidance measures. According to the relation between the actual value of CRI and risk threshold, the decision support rules are summarized, and the specific terms of COLREGs to be followed in each encounter situation are given.

• International Journal of Naval Architecture and Ocean Engineering
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• v.12 no.1
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• pp.541-551
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• 2020

Based on the trend, there have been numerous researches analysing the ship collision risk. However, in this scope, the navigational conditions and external environment are ignored or incompletely considered in training or/and real situation. It has been identified as a significant limitation in the navigational collision risk assessment. Therefore, a novel algorithm of the ship navigational collision risk solving system has been proposed based on basic collision risk and vulnerabilities of marine accidents. The vulnerability can increase the possibility of marine collision accidents. The factors of vulnerabilities including bad weather, tidal currents, accidents prone area, traffic congestion, operator fatigue and fishing boat operating area are involved in the fuzzy reasoning engines to evaluate the navigational conditions and environment. Fuzzy logic is employed to reason basic collision risk using Distance to Closest Point of Approach (DCPA) and Time of Closest Point of Approach (TCPA) and the degree of vulnerability in the specific coastal waterways. Analytical Hierarchy Process (AHP) method is used to obtain the integration of vulnerabilities. In this paper, vulnerability factors have been proposed to improve the collision risk assessment especially for non-SOLAS ships such as coastal operating ships and fishing vessels in practice. Simulation is implemented to validate the practicability of the designed navigational collision risk solving system.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.83-88
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• 2006

Evaluation of collision risk plays a key role in developing the expert system of navigation and collision avoidance. This paper presents a new collision risk model formula that is one modification model on the basis of one approach to the evaluation of collision risk using sech function produced by Prof. Jeong in his relevant $articles^{[2][3][4][5]}$. And as a grope in collision risk evaluation field, this paper applied the new model in appraising the collision risk, suggested how to decide the safe range of own ship’'s action. Moreover this paper also analyzed theoretically how to determine the coefficients as describes in the new modification model formula, and suggested the appropriate values as applicable.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.6
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• pp.524-527
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• 2001

In this paper we propose a collision risk decision system for collision avoidance system A collision avoidance system carries out collision avoidance based on collision risk of unknown obstacle. In the traditional researches, using DCPA and TCPA for calculating the collision risk has problem that they produce a same collision risk for ship which located in the given distance. The solves the problem we use DCPA, TCPA, and VCD for calculating collision risk. A proposed system has two advantages that is produce more detailed collision risk and reflects the international Regulations for Preventing Collision at Sea.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.3
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• pp.319-324
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• 2018

The collision problem is one of the design factors that must be carefully considered for the risk of collision occurring during the operation of ships and offshore structures. This paper presents the main results of the ship collision study, and its main goal is to analyze potential crash scenarios that may occur in the FLNG (Floating Liquefied Natural Gas) considering the likelihood and outcome. Consideration being given to vessels visiting the FLNG and surrounding vessels navigating around, such as functionally supported vessels and offloading carriers. The scope includes vessels visiting the FLNG facility such as in-field support vessels and off-loading carriers, as well as third party passing vessels. In this study, based on QRA (quantitative risk assessment), basic research methods and information on collision are provided. Based on the assumptions and methodologies documented in this study, it has been possible to clarify the frequency of collision and the damage category according to the type of visiting ship. Based on these results, the risk assessment results related to the collision have been derived.

• Journal of Navigation and Port Research
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• v.28 no.9
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• pp.799-802
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• 2004

Evaluation of the quantitative risk of collision plays a key role in developing the expert system of navigation and collision avoidance. This study analysed thoroughly how to determine the threshold of avoidance sector as described in the new evaluation of collision risk, and suggested the collision risk obtained by the alteration of course and/or speed in order to pass clear qf each danger zone as the threshold of avoidance sector.

• Journal of Navigation and Port Research
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• v.27 no.6
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• pp.619-624
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• 2003

Evaluating the risk of collision quantitatively plays a key role in developing the expert system of navigation and collision avoidance. This study analysed thoroughly how to determine the threshold function related to the avoidance time as described in the new evaluation of collision risk using sech function, and developed the appropriate equation as applicable.

• Journal of Navigation and Port Research
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• v.31 no.2
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• pp.121-126
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• 2007

Evaluation of collision risk plays a key role in developing the expert system of navigation and collision avoidance. This paper presents a new collision risk model formula that is one modification model on the basis of one approach to the evaluation of collision risk using sech function produced in earlier studies. And as a tool of the evaluation field of ship collision, this paper applied the new model in appraising the collision risk and represented how to decide the safe range of own ship's action. Moreover this paper also analyzed theoretically how to determine the coefficients as described in the new modification model, and suggested the appropriate values as applicable.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.45 no.2
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• pp.106-113
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• 2009

For the safety and cost reduction in the navigation, the automatic and intelligent system has been developed for the vessel, and the most important factor in the system is to decide the collision risk exactly. In this paper, we propose an advanced collision risk decision system for collision avoidance of the system. The conventional researches using DCPA and TCPA for calculating the collision risk have a problem to produce a same collision risk regardless of bearings for the ships, if they are located in the same distance from own ship. To solve this problem, in addition to DCPA and TCPA, we introduce the factor of VCD(variation of compass degree) and constant, CR which derived from COLREG'72(International Regulation for Preventing Collision at Sea, 1972) for evaluating the collision risk including even the burden of own ship navigator due to the encountering angle of each vessels. We decided the collision risk legally by the rule considering the relative situation of vessels. And therefore, the proposed system has two advantages, of which one is to produce more detail collision risk and another is to reflect the real underway situation in conformity with the rule.