• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.3
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• pp.295-301
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• 2018

This study compares optimization algorithms for efficient estimations of ship's hydrodynamic coefficients. Two constrained algorithms, the interior point and the sequential quadratic programming, are compared for the estimation. Mathematical optimization is designed to get optimal hydrodynamic coefficients for modelling a ship, and benchmark data are collected from sea trials of a training ship. A calibration for environmental influence and a sensitivity analysis for efficiency are carried out prior to implementing the optimization. The optimization is composed of three steps considering correlation between coefficients and manoeuvre characteristics. Manoeuvre characteristics of simulation results for both sets of optimized coefficients are close to each other, and they are also fit to the benchmark data. However, this similarity interferes with the comparison, and it is supposed that optimization conditions, such as designed variables and constraints, are not sufficient to compare them strictly. An enhanced optimization with additional sea trial measurement data should be carried out in future studies.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2007.12a
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• pp.29-30
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• 2007

This paper deals with effect of wind forces and moment acting on the training ship SAE NUR/. The results of drift angle and counter rudder angle due to wind effect are calculated by using the static equilibrium method especially with nonlinear mathematical expression, and then the critical wind velocity is found out. The given results am be applied directly to T/S SAE NURI in handling under the wind condition and used for merchant ships as a referential tool.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.7
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• pp.782-790
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• 2006

The evaluation systems in SHS(Ship Handling Simulator) or ERS(Engine Room Simulator) give trainees the opportunity to feedback how they responded suggesting them the operation result by scores. If SHS and ERS are integrated each other by network to enable the synchronous training for both deck and engine officers these systems need to include inherently the function of integrated evaluation which produces the evaluation score for the team play of deck and engine officers. The integrated evaluation is effective especially when assessing the responses at emergency situation of ship or the matter of efficiency of ship operation even if assessors feel difficult in editing simulation scenarios for integrated evaluation. This study focuses on the property of integrated evaluation and considerations when editing them. It suggests also a useful procedure to estimate whether a scenario for integrated evaluation is reasonable and balanced or not based on the analysis in the proprieties and reasonabilities which are to be prepared by assessors before testing trainees or examinees.

• Journal of the Korean Society of Safety
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• v.20 no.3 s.71
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• pp.180-187
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• 2005

The purpose of this study is to investigate safety consciousness of seafares'. The subjects were 437 seafaes' who took a safety education course in Korea Institute of Maritime and Fisheries Technology. This questionnaire was focused on finding the basic data for prevention of industrial accidents, and getting the public opinions and proposals of seafares'. The results obtained by this study are as follows : The average score of safety consciousness for seafares' were 68.82. Current position level of education navigation area classification of ships, ship size, ship age showed significant difference in statistics(p<0.01). Based on these results, this research pointed out the need to review the training manual, development of educational programs, improvement of facilities to improve safety education of ship, etc.

• Journal of Navigation and Port Research
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• v.31 no.7
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• pp.563-568
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• 2007

In this paper, an adaptive neural network controller and its application to automatic berthing control of ship is presented. The neural network controller is trained online using adaptive interaction technique without any teaching data and off-line training phase. Firstly, the neural networks used to control rudder and propeller during automatic berthing process are presented. Secondly, computer simulations of automatic ship berthing are carried out in Pusan bay to verify the proposed controller under the influence of wind disturbance and measurement noise. The results of simulation show good performance of the developed berthing control system.

• Journal of Navigation and Port Research
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• v.32 no.2
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• pp.115-120
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• 2008

This paper deals with effect of wind forces and moment acting on the training ship SAE NURI. The results of drift angle and counter rudder angle due to wind effect are calculated by using the static equilibrium method especially with nonlinear mathematical expression, and then the critical wind velocity is found out. The given results can be applied directly to T/S SAE NURI in handling under the wind condition and used for merchant ships as a referential tool.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.6
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• pp.656-664
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• 2020

This study conducted a self-assessment survey on 50 evaluation items for students majoring nautical science who boarded H University training ships in order to ascertain the degree of improvement in their maritime ability according to the STCW agreement and training period. The trainees' maritime competence and basic understanding of maritime functions were evaluated, and an in-depth analysis was conducted to see how these have changed since their embarkation. The analysis showed a significant improvement in their understanding of maritime functions after the third evaluation in both the first and second semesters. The results also showed areas the trainees need to improve on for each semester's embarkation group, and an additional study plan is needed to make up for the lack of nautical skills in the training course. The result of analysis on the degree of improvement of maritime ability according to the training period of training ships derived from this study can be used for the reorganization of training ships and maritime college curriculum in the future.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.2
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• pp.215-222
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• 2015

To improve the ocean waves of the ship maneuvering simulator, we study and summarize the visualization elements of the ocean waves and the overall direction of their implementation in detail. We categorize the visualization elements of the ocean waves into five groups, including wave surface, wave breaking, interaction, lighting effects, and underwater. We also analyze the design and implementation issues of the visualization of the ocean waves for ship maneuvering simulator with respect to realistic and real-time ocean visualization, ship dynamics, and application purposes. Through the analysis, we have found that the realistic visualization of ocean waves plays an important role in the generation of immersiveness, more accurate ship motion, and the various and controllable simulation scenarios for the ship maneuvering simulator. Additionally, we have confirmed that there are many visualization elements, methods, and limitations to be considered for the visualization of the ocean waves for ship maneuvering simulator, and we have concluded that the systematic design is required before implementation.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.4
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• pp.504-511
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• 2015

In this paper, the results of evaluating the passenger comfort due to the standard deviation of acceleration in vertical and lateral direction regarding the ship response in irregular wave by ordinary strip method in regular wave and energy spectrum using linear superposition theory in order to evaluate the motion of experimental ship are as follows. According to the results of ship response, it was possible to find that, in order to reduce the motion of ship, a ship operating in bow sea was more stable than in quartering sea. In the results of analyzing the standard deviation of acceleration in vertical direction according to each component wave pattern, when there was a wave length of 56m and an average wave period of 6 sec, most of cases showed the peak value. And among them, the standard deviation was 0.35 which was the highest in head sea. And in case of lateral direction, the maximum value was shown in a wave length of 100m and an average wave period of 8 sec. And it was 0.16 in beam sea and ${\chi}=150^{\circ}$. In the evaluation of passenger comfort due to standard acceleration in vertical and lateral direction, it was 80% in head and bow sea. On the other hand, it was shown to be 15% in follow sea. Accordingly, when the expected wave height in a sea area where a training ship was intended to operate was known, it was possible to predict the routing of ship. And altering her course could reduce the passenger comfort by approximately 50%.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.106-107
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• 2022

The ship type identification of the surrounding ship is important information for navigators and VTS officers since they can estimate the maneuverability and near-future route of the ships. However, it is more than frequent that the information is not provided due to transmission trouble and seafarers' unfamiliarity with AIS. Thus, this study suggests predicting ship types through the Random Forest classifier after preparing a training and test dataset that contains ship features and types. The AIS data for Ulsan coast in 2018 was used for this study. The method may provide the effect that many navigators and VTS officers discuss and share the experience of predicting ship types.