• Proceedings of KOSOMES biannual meeting
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• 2004.05b
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• pp.121-125
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• 2004

Recently, High Tensile Steel is adapt to thin plate on the steel structure and marine structure is used widely, It is possible for buckling happens great. Specially, Initial deflection of ship structure happens in place absence necessarily by heat processing of welding or cutting etc. This Initial Deflection is exerted negative impact when thin plate absence complicated nonlinear behaviour accompanied secondary budding. As a result, must idealize initial deflection that occurrence is possible to endow stability and accuracy in the hull structure or marine structure and reflect in early structure design considering secondary buckling. Longi direction of compressive load interacts and analyzed finite element series analysis that apply various kinds initial deflection shape measured actually on occasion that is arranged simply supported condition in this research. Applied ANSYS (elasto-plasticity large deformation finite element method) to be mediocrity finite element program for analysis method and analysis control used in Newton-Raphson method & Arc-length method.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.83-88
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• 2004

Recently, High Tensile Steel is adapt to thin plate on the steel structure and marine structure is used widely. It is possible for buckling happens great. Specially, Initial deflection of ship structure happens in place absence necessarily by heat processing of welding or cutting etc. This Initial Deflection is exerted negative impact when thin plate absence complicated nonlinear behaviour accompanied secondary buckling. As a result, must idealize initial deflection that occurrence is possible to endow stability and accuracy in the hull structure or marine structure and reflect in early structure design considering secondary buckling. Longi direction of compressive load interacts and analyzed finite element series analysis that apply various kinds initial deflection shape measured actually on occasion that is arranged simply supported condition in this research. Applied ANSYS (elasto-plasticity large deformation finite element method) to be mediocrity finite element program for analysis method and analysis control used in Newton-Raphson method ＆ Arc-length method.

• Journal of Navigation and Port Research
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• v.30 no.3 s.109
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• pp.203-209
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• 2006

Maritime transport has been occupying the biggest part of the container transportation market. With regard to container terminal management, the planning technology and the space allocation system on the yard are very significant factors to secure the stability of ship and to ensure the reliability of schedules of ship throughout keeping barycenter of vessel by right loading and fast handling of cargoes. The purposes of this paper are to illustrate the existing yard management systems such as Grouping method and Random Grounding method, and then to evaluate and compare the efficiency of yard availability between the existing management system(Grouping method) and Random Grouping which uses the forecasted inbound cargo volume at the gate by Time Base Operation.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.4
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• pp.317-326
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• 2020

In this study, damages caused by flash fire, overpressure, and thermal radiation based on the sizes of leak holes were evaluated using the areal location of hazardous atmospheres when natural gas leaked owing to the damage of pipeline in a LNG fueled ship. In addition, environmental variables (wind speed, atmospheric temperature, and atmospheric stability) and process variables (pipe pressure and pipe length) were classified to analyze the damage impact ranges caused by various scenarios. From the results, the damage range caused by the environmental variables was the largest, followed by overpressure and thermal radiation. Additionally, for the process variables, regardless of the pressure, length, or size of the leak holes, the damage range attributed to flash fire was the most significant, and the damage range was high in the order of overpressure and thermal radiation, similar to the environmental variables. The larger the size of the leak holes, the higher the values of the environmental and process variables, and the higher the damage range caused by jet fire compared to the environmental variables.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.49-52
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• 2008

The plain and simple shape water front structure were designed and installed for wave protection and wave resistance. But the installation of these plain and simple structure cause deficiency of environmental affinity. Also the resonance phenomena from the reflective wave and shipwave of the harbor incident wave caused high tide and wave, consequently maintaining the tranquility of inside harbor, give difficulty for mooring the ship and loading-unloading, increase the possibility of ship collision at the quray wall and landing place To solve these problems, we develop the environmentally friendly wave dissipation block. And installation efficiency, stability of the blocks through experiment of C.E Block Joint.

• Special Issue of the Society of Naval Architects of Korea
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• 2006.09a
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• pp.112-121
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• 2006

The vertical displacement of a ship on the basis of the sea level is an important parameter for its stability and control. To indicate the displacement on operating conditions, "draft marks" are carved on the hull of the ship in various ways. One of the methods is welding. The position, shape and size of the marks are specified on the shipbuilding rules by classification societies to be checked by shipbuilders. In most cases, high-skilled workers do the welding along the drawing for the marks and welding bead becomes the marks. But the inaccuracies due to human errors and high labor cost increase the needs for automating the work process of the draft marks. In the preceding work, an indoor robot was developed for automatic marking system on flat surfaces and the work proved that the robot welding was more effective and accurate than manual welding. However, many parts of the hull structure constructed at the outdoor are cowed shapes, which is beyond the capability of the robot developed for the indoor works on the flat surface. The marking on the curved steel surface requiring the 25m elevations is one of the main challenges to the conventional robots. In the present paper, the robot capable of climbing vertical curved steel surfaces and performing the welding at the marked position by effectively solving the problems mentioned earlier is presented.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.4
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• pp.520-526
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• 2015

A tragic disaster happened by capsizing O-Ryong 501 trawler at Western Bering Sea in 1st, Dec. 2014. The disaster was caused by the severe weather and the long deferred escape from the storm in fully developed high sea. Lots of sea water from poop deck rushed into the fish ponder with fishes all together after hauling net and then remove the fishes from codend. The vessel became to incline to the one side caused by the weight and the free surface effect of flood sea waters and fishes at initial stage. In spite of crews all effort to discharge the waters, but the work was not achieved successfully. For the worse thing, the order of abandon ship was issued too late. After all, the ship capsized and sank, then almost crews became to the victims of the casualty including captain. In this paper, author carried out restrictively the calculation of dynamic factors influenced on the disaster including the weather condition and effects of the flood sea waters, and found out that the most important causes of the disaster were the decrease of stabilities, GM was decreased from 0.9m to 0.08 m, and the high waves which led to the vessel disaster.

• Journal of the Society of Naval Architects of Korea
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• v.49 no.5
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• pp.391-399
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• 2012

This paper presents a method of hull form design for the assistant vessel which is used both as a lighting boat and a fish carrying boat for the fleet of newly formated purse seiner vessels. The optimum hull form parameters are searched by the Sequential Quadratic Programing(SQP) method with the power estimation method of Van Oortmerssen. The prismatic curve is redesigned from that of the reference hull by the Lackenby method. Through the modification of the hull form by using a CAD system, the design procedure is completed. The resistance performances of the reference and the modified hull forms are estimated by using a numerical simulation method. Also, the estimation of seakeeping ability and stability for the modified hull forms are carried out. And then, an optimum hull form is proposed for the designed hull form. Ship model tests for the reference and the designed hull forms are carried out at ship model basin. The results of the experiments show that the effective horse power of the designed hull form is about 22% smaller than that of the reference hull form at design speed. The designed hull form proposed in this study will contribute to the development of the hull form for Korean large purse seiner vessels.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2005.10a
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• pp.175-179
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• 2005

Treatment of Emulsion is very important to development of Bilge Separator for new IMO Regulation. It is too difficult to demulsify the emulsion in the bilge waste water, so we use chemical treatment to break emulsion stability. Broken oil particle is treated by flotation. Bilge Separator on the Ship doesn't have enough time to treat Bilge waste water because of small space in the ship. For the solution to this problem, we experiment to find primary factor as coagulator, pH, and amount of coagulator. As the basis of test, we decided coagulator, pH and quantity of coagulator.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.811-814
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• 2009

The HF band maritime communication is have developing to digital methode that techniques should be readied the automatic link establishment of 1:N by coast station to many ship station. Because can use way by polling simply that communication environment calls particular station wicked fellow HF communication states which is much redundancy times for coast station to set link. In amateur radio particular station selective calling do to be using ALE(Automatic Link Establishment) controller by 1:1 automatic link setting way, but expect 1:N link setting by these way in maritime communication very difficult. That is difficult to avoid collision by traffic overload to induce calling of ship stations. Because HF communication considers channel special quality traffic state radio link should be established, and should be applied automatically secures stability of channel as accommodative at traffic overload. In this paper is studied the new radio protocol by 3 step sequency driving of free access, group free access and polling access using multi-tone in single channel.