• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.6
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• pp.717-725
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• 2019

This study is to analyze the effects of the shipping company's core competencies on the satisfaction of the cadets who have completed the consignment practice at the shipping company and on the long-term boarding and onboard company choice after graduation. To do this, the survey was conducted on 211 cadets who completed consignment practice by setting up questionnaires based on prior research. the results of the verification by setting up the hypothesis were then derived as follows: First, the value and persistence of the shipping companies's core competences have a impact on the satisfaction of the boarding practice, with an influence of 32.4 % and 32.7 % respectively. Second, the satisfaction of boarding practice had a significant impact on the choice of the boarding companies after graduation, with an influence of 49.7 %. Third, it has been found that there is a low influence of 4.5 % between the satisfaction of boarding practice and the long-term boarding. Fourth, it was found that 74 percent of the high influence was forming between the selection of the boarding companies and the long-term boarding. Based on research results, it was confirmed that the shipping company would need an effort to improve the satisfaction level of cadets are needed to increase core competencies and to retain excellent crews in order to improve the capability of ship management.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.1
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• pp.1-7
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• 2020

In recent years, cargo lashing has received much importance, to help prevent the sinking of passenger ships due to the failure of vehicle and cargo lashing during the transshipment of cargo. Consequently, the standards for lashing equipment and the structure of car ferries have been revised. According to the current standards, all vehicles loaded on a car ferry sailing in smooth sea areas must be secured if the wind speed and wave height exceed 7 m/s and 1.5 m, respectively. In this study, we measured the roll and pitch of a passenger ship sailing in smooth sea areas, and compared the measurements with the results of the New Strip Method (NSM). The vessel had a maximum pitch of 1.41° and a maximum roll of 1.37° at a wind speed of 6-8 m/s and a wave height of 0.5-1.0 m, and a maximum pitch of 1.49° and a maximum roll of 2.43° at a wind speed of 10-12 m/s and a wave height of 1.0-1.5 m. A comparison of the external forces due to the motion of the hull and the bearing capacity without lashing indicated that the bearing capacity was stronger. This suggests that vehicles without lashing will not slip or fall due to weather conditions. In future, the existing vehicle lashing standards can be revised after measuring the hull motions of various ships, and comparing the external force and bearing capacity, to establish more reasonable requirements.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.4
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• pp.374-381
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• 2020

According to international regulations, it is mandatory for navigators or engineers to acquire suitable skillsets before their designation as a duty officer on board. One of the most important elements is Maritime English (ME), wherein students are taught a required set of basic skills that enable them to process various documents related to accidents, ship conditions, and inspections. Students have to be equipped not only with the use of general English skills but also with the coherent use of technical terms and phrases. However, due to the unique circumstances that exist in the maritime domain, the methods used for imparting maritime knowledge and the manner in which it is evaluated are restricted. Hence, this study aims to utilize an online Maritime English learning and testing platform that can be accessed on smart devices to analyze its impact on the students' learning process. An experiment was conducted on two groups of cadets, one that used the platform and another group that did not. After six-week, the experiment results showed a significant difference between the ME test scores of the two groups. The test scores were further analyzed by incorporating the students' personal elements to measure the ef icacy of the ME test platform. Therefore, the learning and evaluation processes are expected to be implemented in ways that are appropriate and convenient to specific circumstances and be widely used in the field of maritime education in the future.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.4
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• pp.419-428
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• 2020

The flow past a wall mounted square cylinder, a typical and basic shape of building, bridge or offshore structure, was simulated using URANS computation through adoption of three turbulence models, namely, the k-ε model, k-ω model, and the v²-f model. It is well known that this flow is naturally unstable due to the Karman vortex shedding and exhibits a complex flow structure in the wake region. The mean flow field including velocity profiles and the dominant frequency of flow oscillation that was from the simulations discussed earlier were compared with the experimental data observed by Wang et al. (2004; 2006). Based on these comparisons it was found that the v²-f model is most accurate for the URANS simulation; moreover, the k-ω model is also acceptable. However, the k-ε model was found to be unsuitable in this case. Therefore, v²-f model is proved to be an excellent choice for the analysis of flow with massive separation. Therefore, it is expected to be used in future by studies aiming to control the flow separation.

• Journal of Navigation and Port Research
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• v.44 no.4
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• pp.347-353
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• 2020

Aids to Navigation (AtoN) contribute to preventing marine accidents and protecting marine environment by providing various information such as location information etc. to ships. Recognizing the importance of the AtoN, a 24 won of the AtoN service fee is charged for ships entering and leaving international trade ports. However, while the 24 won of the AtoN service fee has been maintained since its establishment in 1999, the demand for new roles of the AtoN service for autonomous shipping and smart port operations, etc. has gradually increasing with the change of shipping and port 4.0. Thus the purpose of this study was to estimate the appropriate level of the AtoN service fee in accordance with such changes in the shipping and port industries. To accomplish this, a method of recovering the total cost was introduced to the PROOF (Pyeongtaek Regional Office of Ocean and Fisheries). It is estimated that there are four cases in which estimation of the AtoN service fee is estimated in two cases year by year and conversion year, the AtoNs of PROOF are classified into the all and part of a ship using the trade port. As a result of the estimation, the AtoN service fee of PROOF is estimated at 53.78-71.62 won (as of 2019), and 29.78-47.62 won is higher than the today at 24 won. The results of this study can be used as useful basic data for the operation of budgets and policy management considering the role of the AtoN.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.9
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• pp.1150-1155
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• 2014

To prevent the flame spread in FRP vessel in fire, the engine-room of the vessel should be constructed additionally with laminated fire-retardant resin over 3 times or equivalent insulation materials to former according to the relevant standard for FRP vessel structure. It is surveyed that insulation materials called 'Gel coat' are widely used in FRP fishing vessel, however, test method and its criteria for Gel coat are not clearly establish and have not been evaluated yet, while test method and criteria for fire-retardant resin and fire-retardant polyurethane composite are described in test standard for type-approval. In this study, 3 fire-retardant resins, 4 gel coats, 1 flame-retardant paint and 1 polyurethane composite were selected based on the survey and were evaluated according to both IMO FTP Code part 5 and flame-retardant test. When comparing based on CFE values from flame-spread test, average value for 4 gel coats were lower than that of 3 fire-retardant resins. As for flame-retardant test, there were no significant differences between fire-retardant resin and gel coat, based on charred area.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.2
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• pp.171-179
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• 2013

The thermodynamic characteristics of a combined cycle applied with a topping cycle such as a trilateral cycle at relatively high temperatures and a bottoming cycle such as an organic Rankine cycle at relatively low temperatures have been theoretically investigated. This is an electric generation system used to recover the waste heat of the exhaust gas from a diesel engine used for the propulsion of a large ship. As a result, when the boundary temperature between the topping and the bottoming cycles increased, the system efficiencies of energy and exergy were simultaneously maximized because the total exergy destruction rate (${\sum}\dot{E}_d$) and exergy loss ($\dot{E}_{out2}$) decreased, respectively. In the case of a marine diesel engine, the waste heat recovery electric generation system can be utilized for additional propulsion power, and the propulsion efficiency was found to be improved by an average of 9.17 % according to the engine load variation, as compared to the case with only the base engine. In this case, the specific fuel consumption and specific $CO_2$ emission of the diesel engine were reduced by an average of 8.4% and 8.37%, respectively.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.5
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• pp.430-443
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• 2016

This paper involves the constitutionality of the restrictive by-laws established by the 'College of Maritime Science' at the 'Korea Maritime and Ocean University' when they affect the cadet's fundamental rights, particularly, in connection with the training system of the 'Merchant Cadet Dormitory.' The issue in question is whether the school regulations may fall within a judicially permissible boundary in light of the general principles of constitutional rights in that the rules are enacted by the school itself in accordance with the Article 31, Section 4 of the Constitution and largely regulate the cadets' living conditions on a campus. However, the general scrutiny standard the courts apply requires the school enactments to pass three tests to be justified: (1) legislative authorization, (2) proportionality and (3) non-infringement on the essential elements of the fundamental rights as articulated under Article 37, Section 2 of the Constitution. The review in this paper shows that, first, the by-laws at issue find themselves statutorily authorized by the 'Higher Education Act' and the 'Decree of the Establishment of National Schools', with the proportionality as a second part observed within a justifiable scope and the essential elements of the fundamental rights as the third point not being marred. In conclusion, the school's dormitory training system is not found to cross the line and, however, the school authorities still need to keep overseeing the overall training course to secure the constitutional proportionality.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.3
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• pp.170-179
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• 1999

The SUS (Signal, Underwater Sound)-OAT experiment was carried out in the Ulleung Basin of the East Sea on 3 June 1997. The SUS-OAT system consisted of aircraft deployed shots as sources and a vertical line array (VLA) tethered by a receiver ship was used to survey a large area where a mesoscale warm eddy appears frequently. The experiment was carried out such that explosive charges set to detonate at 800 ft depth were dropped in a rectangular ($120{\times}120$ km). Sources were a rapidly deployable SUS charge (MK 61 MOD 0), and receiver is a fixed VLA, 90 m in length (150-240 m in receiver depth), composed of 10 elements equally spaced. The reference ray paths are computed by range-dependent acoustic model in canonical ocean based on the historical data. The singular value decomposition (SVD) method is used to obtain the horizontal perturbation of the temperature fields. Horizontal distributions of temperature fields at 150 m and 200 m depth show a weak warm eddy observed by AXBT and the inversely estimated temperature shows similar patterns in terms of the location of the warm eddy. In conclusion, the SUS-OAT experiment has been successful to estimate the position of warm eddy and its temperature field in the East Sea of Korea.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.9
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• pp.911-917
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• 2015

The objective of this work focuses on the analysis of injection rate and macroscopic spray behavior characteristics with injection pressures as well as combustion and exhaust emission characteristics with injection timing and injection pressure by using a common rail single-cylinder diesel engine. The injection rate was measured by applying the Bosch method, and macroscopic spray behavior characteristics were analyzed with a constant-volume vessel and a high-speed camera. In addition, combustion and emission characteristics were analyzed in a common-rail single-cylinder diesel engine with precise control of fuel injection timing and pressure. For injection pressures of 30MPa and 50MPa, the injection rate was higher at 50 MPa, and the spray development (penetration) was also higher in the same elapsed time. The peak in-cylinder pressure and rate of heat release showed a tendency to decline as injection timing was delayed, and the peak in-cylinder pressure and rate of heat release were slightly higher for higher injection pressures. Higher injection pressures also reduced the mean effective pressure, while the indicated mean effective pressure and torque increased as injection timing was delayed to TDC. Nitrogen oxides had a peak level at injection timings of $BTDC20^{\circ}$(30MPa) and $BTDC15^{\circ}$(50MPa); carbon monoxide emissions were reduced by delaying injection timing from $BTDC30^{\circ}$.