• KIPS Transactions on Software and Data Engineering
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• v.3 no.11
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• pp.503-510
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• 2014

With the development of electronic communication technology, the ship's navigational equipment is being digitized, and it has being studied touch-screen-based navigation user interface. However, due to the influence of environmental factors such as waves, it has a potential problem hazardous marine accident occurs due to incorrect operation, the systematic research in consideration of this be done do not. In this paper, we provide a user interface experimental model to verify the stability that takes into account the external environment of the touch-screen input on. Further, we simulated to verify that the interface of the touch screen, the effect of applying the input delay time and the size of the button is obtained through the experimental model proposed. It will be able to greatly contribute to studies of the interface robust touch screen user errors that can be analyzed by the experimental model is proposed to improve the ship, the overall system stability.

• Composites Research
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• v.34 no.6
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• pp.350-356
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• 2021

When a ship with a planing line operates or turns in a straight line, the floating position and trim change according to the speed, and a large resistance is generated on the hull. In this paper, the resistance to a planing line was estimated through the computational fluid dynamics of a leisure boat with improved hull weight and durability by applying a carbon composite material to the hull. The resistance performance of the bow and stern of the 18ft class leisure boat was checked and the flow field of the entire vessel was estimated, and the stability of the planing line was confirmed by comparing the resistance of each trim through numerical analysis. In addition, it was confirmed that the designed planing line could withstand it sufficiently because the force applied to the hull was not large, and The stability of the boat was analyzed by calculating the wavelength of the wave and the length of the ship as the ratio of gravity to the inertial force and checking how much force the rolling occurred.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.4
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• pp.443-450
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• 2014

In this study, we have discussed about the effect of hydrofoil arrangement and longitudinal moment characteristic on longitudinal motion stability of fully-submerged hydrofoil by the experiment of tandem hydrofoil model. First of all, tandem hydrofoil model that has canard wing arrangement has been made and characteristics of lift force and drag force by performing the lift force and drag force measuring experiment has also been estimated. Besides, tandem hydrofoil model's wing arrangement which has the initial stability and self stability of longitudinal motion has also been determined. In longitudinal stability experiment of tandem hydrofoil model, the motion characteristic of pitch and heave and the longitudinal stability of foil borne condition by variation of self stability of longitudinal moment and longitudinal distance are estimated. The result from the experiment and it's important conclusion can be described as below; Increase the self stability for longitudinal moment, the higher self stability for pitch motions in a constant pitch angles. By increasing the self stability for longitudinal moment, the range of fluctuation of pitch motion and heave motion for pitch angle also will change relatively small and longitudinal stability is excellent. Lastly, when the lift force of hydrofoil is remain constants, we can conclude that securing the enough self stability for longitudinal moment is essential for stable foil borne condition of tandem hydrofoil.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.1003-1007
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• 2008

Even if the HF band SSB maritime data communications service company has operating a target Of the member ship, because of unprepared. the radio link protocol that has been question accordance with increase of calling redundancy at traffic overload. Although free signal has operating for traffic of the next ship, but cannot avoid the collision in mutual calling ships. In feature of HF band SSB channel that radio link must be established by automatical, stability and adaptive at over load. In this factor, this paper is studied the new radio protocol by 3 step sequency driving of free access, group free access and polling access.

• Korean Journal of Computational Design and Engineering
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• v.21 no.1
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• pp.90-98
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• 2016

When ships and offshore plants are flooded or the floating crane is equipped with a heavy object, these floating structures are excessively inclined. In this case, immersion, heel, and trim affecting the hydrostatic restoration performance are very large and are coupled each other. In this paper, in order to calculate a static equilibrium position of floating structures with excessive inclination, the nonlinear governing equations were constructed by sequential linearization. In the governing equation, the immersion, heel, and trim are fully coupled, and the equations are represented using a plane area, a primary moment, and a moment of inertia of the water plane area. Therefore, it is possible to calculate the additional factor related the water plane area for estimating stability. Position and orientation of the floating structure are obtained by iterative calculation. The calculated results are compared with the previous studies in the aspect to the performance and the accuracy.

• Journal of Ocean Engineering and Technology
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• v.23 no.6
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• pp.53-60
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• 2009

Recently, since there are several problems in space, the infra-structure and the facilities in the contiguity of the existing harbors due to the trend of enlarging the container capacity of the large container vessel, a special floating platform named as the Mobile Harbor has been proposed conceptually as an effective solution of those problems. Two kinds of hull shapes, a conventional mono-hull type and a catamaran type, are proposed as midway feeders to transfer containers to the harbor on land from a large container ship on near shore. In this study, the motion response and mooring analysis are carried out for comparing the global performance of two types of Mobile Harbor. Robot arm mooring facility specially is devised and newly tried to use for the safe fixation of a large container ship and the Mobile Harbor on near shore. It would be expected for this comparison study to give a guideline to design the efficient hull form for a midway loader.

• Journal of Ocean Engineering and Technology
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• v.34 no.3
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• pp.167-179
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• 2020

Recently, the increasing importance of artificial intelligence (AI) technology has led to its increased use in various fields in the shipbuilding and marine industries. For example, typical scenarios for AI include production management, analyses of ships on a voyage, and motion prediction. Therefore, this study was conducted to predict a response amplitude operator (RAO) through AI technology. It used a neural network based on one of the types of AI methods. The data used in the neural network consisted of the properties of the vessel and RAO values, based on simulating the in-house code. The learning model consisted of an input layer, hidden layer, and output layer. The input layer comprised eight neurons, the hidden layer comprised the variables, and the output layer comprised 20 neurons. The RAO predicted with the neural network and an RAO created with the in-house code were compared. The accuracy was assessed and reviewed based on the root mean square error (RMSE), standard deviation (SD), random number change, correlation coefficient, and scatter plot. Finally, the optimal model was selected, and the conclusion was drawn. The ultimate goals of this study were to reduce the difficulty in the modeling work required to obtain the RAO, to reduce the difficulty in using commercial tools, and to enable an assessment of the stability of medium/small vessels in waves.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.643-648
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• 2005

Generally, ships have marks of various shapes on outside of the hull. Among them, so called "Draft Mark" indicates the distance from the bottom of the keel to the waterline. Draft marks are used to determine the displacement and other properties of the ship for stability and control purposes. These marks are made up of welding bead or sticking the steel plate on outside of the hull. To improve the confidence level of the ship owner, quality and accuracy of the draft mark is very important. So the automatic mark welding robot is used to enable a high quality and accurate manufacturing line. To improve the system portability, the system is divided into two distinct parts, namely mechanical part and control part. Mechanical part is robust, a lightweight, and easy to dismantle. The control part consists of an in-house developed controller, which is based on embedded Linux. Also, the control part consists of power line communication module to ensure the applicability of the controller in manufacturing line. In this paper, the methodologies of control and configuration of the robot are discussed.

• Journal of Ocean Engineering and Technology
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• v.23 no.5
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• pp.9-14
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• 2009

The green water on deck has many harmful effects on the vessel in rough seas such as damages to hull structures, damages to cargos, increase of the downtime, decrease of the stability, and so on. Floating Production Storage and Offloading vessels (FPSOs) are operated in a specific location and are normally positioned to meet mostly head or bow waves in order to reduce the roll motions. But this makes FPSOs more vulnerable to green water around the bow region therefore the bow shape should be properly designed to mitigate the green water damage. In this paper, experimental results in regular head waves for three kinds of bow shapes are compared and some design considerations are proposed, with the building a database for computational fluid dynamics (CFD) validation in mind.

• Journal of the Korean Institute of Navigation
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• v.20 no.3
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• pp.1-11
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• 1996

The accuracy for determining fishing ground and for setting fishing gear location, and the repeatability of ship position vary depending on fishing methods. Especially, Loran-C has been served to give fisherman highly accurate ship's position, and a number of fishing vessel are equipped with it's receivers. In this paper, in order to evaluate the accuracy of Loran-C fix of Korean chain in Korean southeast coast, the authors examined and analyzed the data of the receiver of Loran-C(LC 90, Furuno) and GPS(AccNav $Sport^{TM}$, Eagle) measured automatically and continuously for 2 seconds at interval of 5minutes during 2hours from $11^{th}$ to $21^{st}$, July, 1996 at six observed points, that is, Pusan, Wolnae, Pangojin, Chongja, Kampo and Kuryongpo in Korean southeast coast. As the result obtained, Loran-C signals showed little fluctuation with good reprodutibility. Good stability of Loran-C signals was indicated by the small value of the standard deviation 0.064~0.094$\mu\textrm{s}$. Although determination of the observed position could not be completely accurate, the extent of the error was estimated smaller than 0.35 nautical mile.