• Journal of Ocean Engineering and Technology
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• v.30 no.6
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• pp.468-473
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• 2016

This paper focuses on the estimation of local ice loads exerted from ship-ice interaction processes. The Korean IBRV ARAON was used to perform field ice trials during her 2015 Arctic voyage. During ARAON's general ice transit, a total of 72 channels of data from both strain gauges on the inner hull plates and those installed on the transverse frames of the ARAON's bow section structures were analyzed to calculate the local ice loads. The local ice loads estimated from the analysis of the shear strain data measured on the side frames were compared to those from the hull plate pressures.

• Journal of Ocean Engineering and Technology
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• v.30 no.6
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• pp.440-450
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• 2016

The capsizing and consequent sinking of a coastal car ferry was recently reported, with numerous human casualties. The primary cause was determined to be a sudden turn with improperly stowed and secured cargo. Part I of this study introduces how long term acceleration components are determined from seakeeping analyses. A carferry with a displacement of 1,633 tonf was selected as the target vessel. Sea data that included the significant wave heights and periods were collected at four observation buoys, some of which were far away from two main voyage routes: Incheon-Jeju and Pusan-Jeju. Frequency response analyses were performed to obtain the linearized radiation force coefficients, hydrostatic stiffnesses, and wave excitation forces. Time response analyses were sequentially performed to produce the motion-induced acceleration processes. The probabilistic distributions of the acceleration components were determined using a peak and valley counting method. Long term extreme acceleration components were proposed as a final result.

• Journal of Navigation and Port Research
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• v.34 no.3
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• pp.189-194
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• 2010

As the seriousness of the global environment is gaining our attention recently, studies on application of LCA(Life Cycle Assessment) to ship are being carried out dynamically in various industrial fields. This study was carried out to examine the application of LCA to ships and was focused on the inventory analysis on global warming gas from merchant cargo ships. Two merchant cargo ships were adopted as ship models. Actual voyage data of at last several years was used to analysis the ship's exhaust gas inventory. The analysis shows how many weight of global warming gas being exhausted to transport 1 ton of each cargo per 1 nautical mile.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.10a
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• pp.33-34
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• 2015

The voyage and cargo volume passing through the Arctic route (NSR) have been gradually increased. The ship-ice collision is one of the most biggest factors threatening the safety navigation of ice-going ships. A lot of researchers are trying to reveal the ship-ice collision mechanism. In this study, some tests that a model ship is forced to collide with disk-shaped synthetic ice are carried out in a towing tank. Then, ice floe's motion (velocity and trajectory) is measured by machine vision inspection.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.6
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• pp.1812-1821
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• 2016

The purpose of this study is to survey input data error of ship automatic identification system (AIS) and suggest its improvement. The effects of AIS were observed. Input data error of AIS was investigated by dividing it into dynamic data, static data by targeting actual ships and its improvement method was suggested. The findings are as follows. Looking into accidents before and after AIS is enforced to install on the ship, total collision were decreased after AIS installed. Static data error of AIS took place mainly in the case that ship name, call sign, MMSI, IMO number, ship type, location of antenna (ship length and width) were wrongly input or those data were not input initially. Dynamic data error of AIS was represented by input error of ship's heading. As errors of voyage related data take place as well, confusion is made in sailing or ship condition. Counter measures against the above are as follows. First, reliability of AIS data information should be improved. Second, incessant concern and management should be made on the navigation officers.

• Journal of the Society of Naval Architects of Korea
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• v.55 no.5
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• pp.415-420
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• 2018

The development of sail gas has increased the production of ethane as well as natural gas. The decline in the market price for ethane has led to a change in the petroleum-based ethylene production process into an ethane-based ethylene production process and an increase in the ethane/ethylene trade volume. Large-scale ethane/ethylene carrier have been needed due to an increase in long-distance trade from the US, and cargo type change have leaded to consider a liquefaction process to re-liquefy Boil-Off gas generated during the voyage. In this paper, the liquefaction system of Liquefied Ethane Gas carrier was evaluated with Low-GWP (Low-Global Warming Potential) refrigerant and process parameters, Boil-Off Gas pressure and expansion valve outlet pressure, were optimized. Low-GWP refrigerants were propane (R290), propylene(R1270), carbon dioxide(R744) was considered at two type of liquefaction process such as Linde and cascade cycle. The results show that the optimal pressure point depends on the individual refrigerant and the highest liquefaction efficiency of carbon dioxide (R744) - propane (R290) refrigerant.

• Journal of the Society of Naval Architects of Korea
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• v.57 no.3
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• pp.152-159
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• 2020

Ship owners had pursued higher benefits by demanding the new design and construction of ships with higher operational efficiency. There was a necessity for shipyards to suggest a more economical design and advanced operation concept in order to meet the demands. Especially, since BOG combustion and activation of the re-liquefaction unit had to be taken into account in ship design in addition to fuel oil and gas consumption, the evaluation of the operating efficiency considering the technological trends was necessary. In this paper, it was aimed to study the design philosophy and operation strategy by considering the effect of fuel oil and gas consumption, BOG combustion, and activation of the re-liquefaction unit on the operating cost for laden voyage according to ship speed, BOR, and activation of the re-liquefaction unit. For this purpose, the costs were acquired by conducting the sailing simulation of an LNGC based on a mathematical model including the maneuvering equations of motion. The design philosophy and operation strategy was reviewed in terms of the operating cost.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.05a
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• pp.41-42
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• 2018

This study is about the prediction of ship's roll motion characteristic which has been used for evaluating ship's seakeeping performance. In order to obtain the ship's roll RAO during voyage, this paper utilized machine learning-based surrogate model. By comparing the prediction result data of surrogate model with test data, we suggest the best approximation technique and data sampling interval of the surrogate model appropriate for predicting the ships' roll motion characteristic.

• Smart Media Journal
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• v.2 no.1
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• pp.42-47
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• 2013

The paper presents VDR system for efficiency of ocean navigation device and how to output and to save data using this system as well as compressed digital data and analog video output from the camera are utilized at the same time. The compressed digital data is used to store video for VDR device while analog video is used to display on screen in real-time so that VDR system saves the load on SD memory card without navigation terminal and output it with real-time video. Also, the control method using VDR system are proposed for saving and outputting data.

• Journal of the Korean Institute of Navigation
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• v.19 no.1
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• pp.33-48
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• 1995

In the process of containerization, the problem of regional maldistribution of container management plan arises seriously due to several factors like a number of unbalances of containers between loading and discharging ports. This study focus on the minimizing cost. This study is composed of two models which in effective management decision making show decision of the number of containers and transfer of empty containers. One is decision of the number of containers which carriers should possess by appropriate forecasting and the other is effective management decision making which includes the transfer of empty containers on calling ports. This study has suggested as follows, First, the Time Series analysis method, especially the "Exponential Smooting with Trend Adjustment" was used to forecast the trade volumes for the designated traffic route. Second, the Time Series analysis method in deciding the optimal number of owned container at the unbalances trade situation between East Bound and West Bound service, most important variables were found such as total traffic volume, the calling interval at a port, the number of days of voyage and the length of stay on shore of container for the optimal number of owned container. Third, effective management decision making model, which makes it possible to analyze the impacts of change in important matters such as lease and positioning policy, and actually influence decision making.on making.