• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.100-102
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• 2016

Every crew are in great peril that they should put out a fire on board in person due to a property of ship isolated. Accordingly, it is essential to verify whether the fire-fighter's outfits and fire-fighting scenarios in accordance with present regulations are safe and effective actually. As a result of comparison between shore fire-fighter's outfits and fire-fighting scenarios and those on ship and statistics calculation of the place and frequency of the fire of actual ship, present limitations of fire suppression system and fire-fighter's outfits were proved. In addition, derive the distance to the place on ship that has highest frequency of fire occurrence from examining actual ship's drawings according to their description and size. Finally from experiments in more experimental groups by changing numbers of actual fire-fighters and environment and conduction of survey of a number of crew in active service on ship, the most effective fire-fighter's outfits system and fire-fighting scenarios will be derived.

• Journal of Ocean Engineering and Technology
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• v.19 no.6 s.67
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• pp.16-21
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• 2005

In the design of super tankers or LNG carriers, which transport a large amount of liquid in the cargo tanks, the structural d11mage due to liquid sloshing is an important problem. The impact pressure from sloshing is most violent when the liquid motion of a partially filled tank is in resonance with the motion of a ship. In this study, the sloshing natural periods of a baffled tank, often installed to reduce liquid motion, is analyzed. A variational method is adopted to estimate the sloshing natural periods for a prismatic cargo tank with baffles of arbitrary filling depth of liquid; the results are compared with Lloyd's Register regulations on sloshing periods. In this study, using an effective liquid-fill-depth concept, sloshing periods for a baffled tank can be expressed by the same form as rectangular prismatic tanks without baffles. In contrast to Lloyd's Register regulations, which can be applicable only to cargo tanks with constant baffle size and distribution, the present results can be applicable to cases of variable baffle size and distribution.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.4
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• pp.77-84
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• 2004

Active control is regarded as one of the most efficient and economic countermeasures to reduce excessive vibration of ship superstructure. However, it is difficult to find its practical application in real ships in spite that many studies on such systems have been done. In this study, for the practical use of an active control system to reduce ship superstructure vibration, we have developed an active vibration compensator consisting of a mechanical actuator having compact size and expected lifetime over 20 years, its control panel including exclusive signal processing and computing board, sensors to detect phase and vibration, and its operation software providing various user-interface functions. From the performance verification test of the system at a 5,500 TEU container carrier, we have confirmed the system could reduce ship superstructure vibration of a harmonic component of main engine rotating frequency up to 0.1 mm/s.

• Journal of Ship and Ocean Technology
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• v.11 no.1
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• pp.11-24
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• 2007

Better prediction of a ship's manouevrabilty in initial design stage is becoming more, important as IMO manoeuvring criteria has been activated in the year of 2004. In the present study, in order to obtain more exact and reliable results for ship manoeuvrability in the initial design stage, numerical simulation is carried out by use of RANS equation based calculation of hydrodynamic forces exerted upon the ship hull. Other forces such as rudder force and propeller force are estimated by one of the empirical models recommended by MMG Group. Calculated hydrodynamic force coefficients are compared with those obtained by empirical models. Standard manoeuvring simulations such as turning circle and zig-zag are also carried out for a medium size Product Carrier and the results are compared with those of pure empirical models and manoeuvring sea trial. Generally good qualitative agreement is obtained in hydrodynamic forces due to steady oblique motion and steady turning motion between the results of CFD calculation and those of MMG model, which is based on empirical formulas. The results of standard manoeuvring simulation also show good agreement with sea trial results.

• Journal of Ocean Engineering and Technology
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• v.34 no.5
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• pp.325-333
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• 2020

As regulations concerning ship vibration and noise are becoming stricter, considerable attention is being drawn to prediction technologies for ship vibration and noise. In particular, the resonance and lock-in phenomena caused by vortex-induced vibration (VIV) have become considerably important with increases in the speed and the size of ships and ocean structures, which are known to cause structural problems. This study extends the fluid-structure interaction (FSI) analysis method to predict resonances and lock-in phenomena of high modes and VIV of ship rudders. Numerical stability is secured in underwater conditions by implementing added mass, added damping, and added stiffness by applying the potential theory to structural analysis. An expanded governing equation is developed by implementing displacements and twist angles of high modes. The lock-in velocity range and resonant frequencies of ship rudders obtained using the developed FSI method agree well with the experimental results and the analytic solution. A comparison with local vibration guidelines published by Lloyd's Register shows that predictions of resonances and lock-in phenomena of high modes are necessary in the shipbuilding industry due to the possible risks like fatigue failure.

• Journal of Navigation and Port Research
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• v.29 no.1 s.97
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• pp.29-34
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• 2005

A mis-handling of the ship operators, treated as one qf the main causes of a ship accidents, normally has caused a ship to collide with obstacles like a reef, a rock and other ships etc. since their ability has been declining little by little even though the port conditions have been getting worse. The ship needs a highly sophisticated technology as her size and speed increase as the ship have been demanded. For example, Auto Avoidance Control System gradually has been receiving a growing interest to control the entire ship safely. From that purpose, this research has been done. The research was based on the MMG mathematical model, used Surge-Sway-Yaw-Roll motion equation and Fuzzy theory for calculating the collision-risk Also the research successively was done when the ship encountered continual multitude ships.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.2
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• pp.139-148
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• 2020

The most important factor affecting the berthing energy generated when a ship berths is the berthing velocity. Thus, an accident may occur if the berthing velocity is extremely high. Several ship features influence the determination of the berthing velocity. However, previous studies have mostly focused on the size of the vessel. Therefore, the aim of this study is to analyze various features that influence berthing velocity and determine their respective importance. The data used in the analysis was based on the berthing velocity of a ship on a jetty in Korea. Using the collected data, machine learning classification algorithms were compared and analyzed, such as decision tree, random forest, logistic regression, and perceptron. As an algorithm evaluation method, indexes according to the confusion matrix were used. Consequently, perceptron demonstrated the best performance, and the feature importance was in the following order: DWT, jetty number, and state. Hence, when berthing a ship, the berthing velocity should be determined in consideration of various features, such as the size of the ship, position of the jetty, and loading condition of the cargo.

• Journal of the Korean Society of Marine Environment & Safety
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• v.10 no.2 s.21
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• pp.29-34
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• 2004

The marine traffic congestion has increased due to the expansion of vessel traffic volume in Korean coastal waterway these days. Heavy traffic could bring serious marine casualties which cause the loss of human lives, properties and marine pollution in coastal area. In this paper, the probability analysis of marine casualties in Korean coast. To achieve this aim, clears up the cause of accident and examines closely the mutual relations among marine casualties, weather condition, and marine traffic volume. These casualties are classified into several patterns or the point of view of ship's size, ship's type and ship's age and its characteristics of each pattern are described In detail.

• Proceedings of KOSOMES biannual meeting
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• 2004.05b
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• pp.13-18
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• 2004

The marine traffic congestion has increased due to the expansion of vessel traffic volume in Korean coastal waterway these days. Heavy traffic could bring serious marine casualties which cause the loss of human lives, properties and marine pollution in coastal area. In this paper. the probability analysis of marine casualties in Korean coastal To achieve this aim, clears up the cause of accident and examines closely the mutual relations among marine casualties, weather condition, and marine traffic volume. These casualties are classified into several pattens or the point of view of ship‘s size, ship’s type and ship‘s age and its characteristics of each patten are described in detail.

• Journal of the Society of Naval Architects of Korea
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• v.37 no.4
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• pp.48-55
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• 2000

A basic research of air bubble locus around the ship hull is performed to know the bubble's behavior which is generated around the hull surface. In this paper. bubble's behavior around the ship hull is calculated and experimented with the variation of bubble size and the location of bubble generation. For the use of the equation for bubble locus, Kawakita's equation which include the effect of bubble buoyancy is adopted. For the numerical simulation. a finite difference method based on the MAC method is used. Also experiments are performed about series 60 hull form at CWC. The results of calculation are compared with those of experiment.