• Journal of the Ergonomics Society of Korea
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• v.36 no.5
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• pp.447-458
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• 2017

Objective: The purpose of this study is to present the basic guidelines for preventing human error by measuring and analyzing the risk of collision perceived by the ship operator in the collision risk situation by using Korea Coast Guard patrol ships. Background: In the last 5 years, 97.5% of the causes of ship collision occurred at the sea was caused by human factors. However, the rate of marine accidents due to human error has not been reduced yet. Experiments and researches on the ship operators using the ships in actual operation are rarely performed. Method: Using two K.C.G Ships on the sea, the ship measured by 30 persons who are the subject of the ship (ship operator) when both ships approach and the relative distance gradually decreases in four encounter situations, perceived ship collision risk (PSCR) data were analyzed by statistical analysis. Results: The age and boarding career of the ship operator in the situation of ship collision risks encountered a negative impact on perceived collision risk in all four opposing encounter situations S1 ($000^{\circ}$), S2 ($045^{\circ}$), S3 ($090^{\circ}$) and S4 ($135^{\circ}$) respectively. That is, the higher the age of the ship operator, the lower the perceived risk of collision and the lower the age, the higher the risk of collision. Also, there was a difference between the average of group A (20~30 years) and group B (40~50 years) according to age of the ship operators at $000^{\circ}$, $045^{\circ}$ and $090^{\circ}$ and there was no difference at $135^{\circ}$. The mean difference of the experience of boarding career was also significantly different between group A (less than 4 years) and group B (more than 5 years), but there was no significant difference at $135^{\circ}$. Conclusion: The results showed that age and boarding career of the ship operators had negative impact on perceived collision risk and there was a difference in perceived risk of collision according to age and abundance of boarding career. As a result, by focusing on the ship operators who are in the age group of 20~30 years old and have less than 4 years of experience in boarding the ship. It is expected that the effect of prevention of marine accidents can be expected by avoiding collision avoidance. Application: The results of this study can be used as policy data of related organizations to prevent human error of ship operators and as training data of training institutes.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.3
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• pp.41-48
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• 2004

Ship is being operated under a highly dynamic environments and many factors are related with ship's collision and those factors are interacting. So, the analysis on ship's collision causes are very important to prepare countermeasures which will ensure the safe navigation. This study analysed the ship's collision data over the past 10 years(1991-2000), which is compiled by Korea Marine Accidents Inquiry Agency. The analysis confirmed that ‘ship's collision' is occurred most frequently and the cause is closely related with human factor. The main purpose of this study is to propose risk control measures of ship's collision. For this, the structure of human factor is analysed by the questionnaire methodology. Marine experts were surveyed based on major elements that were extracted from the human factor affecting to ship's collision. FSM has been widely adopted in modeling a dynamic system which is composed of human factors. Then, the structure analysis on the causes of ship's collision are performed using FSM. This structure model could be used in understanding and verifying the procedure of real ship's collision. Furthermore it could be used as the model to prevent ship's collision and reduce marine accidents.

• Journal of the Korean Society of Safety
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• v.23 no.1
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• pp.46-50
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• 2008

The purpose of the present study was to investigate the mariner's information characteristics in ship-ta-ship collision situation using the full mission ship-handling simulator. Risk levels of ship-to-ship collision were manipulated by whether the target ship complies with the naval regulations and by movement patterns of target ship. Dependent variables reflecting mariner's information characteristics in ship-ta-ship collision situation were measured in terms of radar detection reaction time, free recall performance of past navigation situation, and subjective ratings for the task difficulty. The results showed that, in general, the mariners appeared to be deteriorated in their radar detection reaction time and free recall performance as the risk of ship-ta-ship collision increased. Also, the mariners tended to rate required tasks more difficult in the high risk ship-ta-ship collision situation.

• 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.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.

• 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.

• International Journal of Naval Architecture and Ocean Engineering
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• v.5 no.2
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• pp.188-198
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• 2013

In constructing a collision avoidance system, it is important to determine the time for starting collision avoidance maneuver. Many researchers have attempted to formulate various indices by applying a range of techniques. Among these indices, collision risk obtained by combining Distance to the Closest Point of Approach (DCPA) and Time to the Closest Point of Approach (TCPA) information with fuzzy theory is mostly used. However, the collision risk has a limit, in that membership functions of DCPA and TCPA are empirically determined. In addition, the collision risk is not able to consider several critical collision conditions where the target ship fails to take appropriate actions. It is therefore necessary to design a new concept based on logical approaches. In this paper, a collision ratio is proposed, which is the expected ratio of unavoidable paths to total paths under suitably characterized operation conditions. Total paths are determined by considering categories such as action space and methodology of avoidance. The International Regulations for Preventing Collisions at Sea (1972) and collision avoidance rules (2001) are considered to solve the slower ship's dilemma. Different methods which are based on a constant speed model and simulated speed model are used to calculate the relative positions between own ship and target ship. In the simulated speed model, fuzzy control is applied to determination of command rudder angle. At various encounter situations, the time histories of the collision ratio based on the simulated speed model are compared with those based on the constant speed model.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.5
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• pp.447-454
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• 2017

Using two large coast guard ships at sea, we created four encounter situations ($000^{\circ}$, $045^{\circ}$, $090^{\circ}$, $135^{\circ}$) with high possibility of collision, from 3 NM up to 0.25 NM. As relative distance was gradually decreased, the subjects were measured at 0.25 NM intervals and perceived ship collision risk (PSCR) was determined by looking at the opponent ship. Characteristics were statistically analyzed using the obtained data. The purpose of this study was to analyze the characteristics of collision risk values obtained from twelve intervals, from 3 NM to 0.25 NM relative to encounter situations by curve fitting with appropriate polynomials, to determine the distance from which the change in perceived collision risk is greatest. As a result, an optimal regression equation for each distance interval was derived from each analysis direction. The greatest variation in average collision risk value was over the range 1.25 ~ 1 NM, and the collision risk value was largest at 1 NM. The maximum change in perceived collision risk was at 1 NM. These results can contribute to preventive guidelines to minimize human error in close proximity situations with a high probability of ship collision.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.6
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• pp.670-678
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• 2018

In coastal waters where the traffic volume of the ship is high, there is a high possibility of a collision accident because complicated encounter situations frequently occurs between ships. To reduce the collision accidents at sea, a quantitative collision risk assessment is required in addition to the navigator's compliance with COLREG. In this study, a new collision risk assessment system was developed to evaluate the collision risk on ship's planned sailing routes. The appropriate collision risk assessment method was proposed on the basis of reviewing existing collision risk assessment models. The system was developed using MATLAB and it consists of three parts: Map, Bumper and Assessment. The developed system was applied to the test sea area with simple computational conditions for testing and to actual sea areas with real computational conditions for validation. The results show the length of own ship, ship's sailing time and sailing routes affect collision risks. The developed system is expected to be helpful for navigators to choose the optimum safe route before sailing.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.663-666
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• 2004

An analysis of the annual frequency of collapse(AF) is performed for each bridge pier exposed to ship collision. AF is computed for each bridge component and vessel classification. The summation of AFs computed over all of the vessel classification intervals for a specific component should equal the annual frequency of collapse of the component. The designer should use judgment in developing a distribution of the vessel frequency data based on discrete groupings or categories of vessel size by DWT. In the present study the effect of vessel classification on the annual frequency of collapse in the ship collision risk assessment is investigated by illustrative numerical examples based on the vessel frequency data of the domestic harbor. The DWT interval for larger vessels has more effect on the ship collision risk. Therefore the expert judgement in determining the larger DWT interval is required because the design impact lateral resistances of bridge components depend on the ship collision risk.