• Journal of Korea Port Economic Association
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• v.30 no.1
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• pp.73-96
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• 2014

Competitiveness of container ports has been traditionally evaluated by capability of individual ports to provide services to customers or their service quality. However, since container ports are connected by container shipping networks to varying degrees, the status of the ports in liner shipping service networks also determines competitiveness of the ports. Sometimes same ports may play different roles in different forms of shipping networks. Shipping network connections that formulate in container ports therefore have more significant impact on their performance than service capabilities they have. This study aims to explore how the shipping and port network has been structured and changed in the past and to examine the network characteristics of ports using Social Network Analysis(SNA). In this SNA study, nodes in the network are the ports-of-call of the liner shipping services and links in the network are connections realized by vessel movements, such that the liner shipping networks determine the port networks. This study, therefore, investigates the liner shipping networks and through its results demonstrates the network characteristics of the ports that are represented by the four centrality indices. This provides port authorities and terminal operating companies with managerial implications to enhance competitiveness from customers' perspectives.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.6
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• pp.646-651
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• 2017

The purpose of this study is to design a proper evaluation method for analysing the safety management efficiency of coastal ship companies, and to verify these evaluation standards by applying them to a representative company. For this purpose, 5 evaluation items and 14 specific sub-evaluation elements have been determined after collecting practical opinions from a group of expert, which consisted of safety managers in passenger ship companies, public servants as a ship inspector, passenger ship operations managers, etc. Next, the safety management levels of 44 coastal passenger ship companies were evaluated using these standards. Finally, the validity of the proposed evaluation method was verified through comparison analysis between the evaluation results and the ratio of major marine accidents. It was determined that companies with low evaluation levels were saw more major marine accidents than other coastal passenger ship companies, spurring greater interest in safety management. In conclusion, evaluation standards allow coastal passenger ship companies to voluntarily assess their safety management level were established. The result can also be applied to analyse the operation efficiency of coastal passenger ship companies.

• Korean Journal of Remote Sensing
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• v.37 no.2
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• pp.177-198
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• 2021

Existing change detection researches have been focused on changes of land use and land cover (LULC), damaged areas, or large vegetated and water regions. On the other hands, increased temporal and spatial resolution of satellite images are strongly suggesting the feasibility of change detection of small objects such as vehicles and ships. In order to check the feasibility, this paper analyzes the performance of existing pixel-based change detection methods over small objects. We applied pixel differencing, PCA (principal component analysis) analysis, MAD (Multivariate Alteration Detection), and IR-MAD (Iteratively Reweighted-MAD) to Kompsat-3A and Google Map images taken within 10 days. We extracted ground references for changed and non-changed small objects from the images and used them for performance analysis of change detection results. Our analysis showed that MAD and IR-MAD, that are known to perform best over LULC and large areal changes, offered best performance over small object changes among the methods tested. It also showed that the spectral band with high reflectivity of the object of interest needs to be included for change analysis.

• Journal of Navigation and Port Research
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• v.45 no.3
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• pp.173-180
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• 2021

Although accounting is one of the core fields of corporate management, few studies have reported accounting phenomena involving shipping companies. In addition, although financial reporting is very important to shipping companies that use several financial tools such as ship finance and financial lease, it is difficult to identify studies investigating shipping companies' financial reporting, especially their earnings management. The purpose of this study is to analyze accrual earnings management behavior of shipping companies. Companies with high debt ratios and net losses are known to have incentives for earnings management. Due to the nature of the industry, shipping companies have a high debt ratio and often report net losses. Accordingly, shipping companies are expected to engage in substantial earnings management. Based on the analysis of KOSP I companies listed on the Korea Exchange from 2001 to 2020, it was found that shipping companies are engaged in higher levels of earnings management than non-shipping companies. Discretionary accrual was used as a proxy variable for earnings management. Discretionary accrual was measured using the modified Jones model of Dechow et al. (1995) and the performance matched model of Kothari et al.(2005). In this study, significant results were derived by comparatively analyzing the earnings management practices, which is one of the major accounting behaviors of shipping and non-shipping companies. Stakeholders such as external auditors, investors, financial institutions, analysts, and government authorities need to be aware of the earnings management behavior of listed shipping companies during their external audit, financial analysis, and supervision. Finally, listed shipping companies must conduct stricter accounting based on accounting principles.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.4
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• pp.413-422
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• 2019

Maritime accidents are always accompanied by human/property damages. If management level ship's of icers properly respond to emergency situation in a correct manner based on knowledge required by international conventions, when maritime accidents occur, it will be possible to minimize such human/property damages. To improve the ability to deal with maritime accidents, this study analyze maritime accident cases to identify which competencies ships' officers' were lacking, compared the emergency response competencies required by international conventions, analyzed various emergency management manuals of shipping companies and carried out questionnaire surveys to suggest improvements of emergency response capability for ship's master. Through the analysis of maritime accidents, it was identified that management level ship's officers lacked competencies regarding damage stability and intact stability, and that the training for emergency response required by international conventions had been insuf iciently carried out. In addition, even though emergency management manuals of ships were generally adequate, it has been identified that there were limitations in terms of practical use of emergency response manual. Therefore, based on the questionnaire, this study proposed the expansion of emergency response training required by international conventions based on use of simulators, and the development of guidelines or manuals for effective and efficient response in emergency situations.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.5
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• pp.535-541
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• 2019

The purpose of this study was to investigate the possibility of fishery in offshore wind farms and evaluate the risk linked to the presence of turbines and submarine cables in these areas. With this objective, we studied an offshore wind farm in the Southwest Sea and the current state of vessels in the surrounding National Fishing Port. The risk assessment criteria for 22 fishing gears and methods were set by referring to the fishing boats; thereafter, the risk was assessed by experts. The fishing gears and methods that could be safely operated (i.e., associated with low risk) in the offshore wind farm were: single-line fishing, jigging, and the anchovy lift net. The risk was normal so that it is possible to operate, but the fishing gears and methods that need attention are: the set long line, drifting long line, troll line, squid rip hook, octopus pot, webfoot octopus pot, coastal fish pot, stow net on stake, winged stow net, stationary gill net, and drift gill net. Moreover, the fishing gears and methods difficult to operate in the of shore wind farm (i.e., associated with high risk) were: the dredge, beam trawl, and purse seine. Finally, those associated with very high risk and that should not be allowed in offshore wind farms were: the stow net, anchovy drag net, otter trawl, Danish seine, and bottom pair trawl.

• Journal of Digital Convergence
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• v.17 no.4
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• pp.95-105
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• 2019

The failure of company management that does not overcome the recession of shipping economy has negative impact on front-end and back-end industries in relation to shipping industry overall. This study aims to derive a measure of government policy support for win-win of ship owners and shippers by performing a survey with experts in ship owners, shippers, and port-related institutions. This study employed a consistent fuzzy preference relation (CFPR) method to provide the priority of government policies. The study results showed that out of all 14 policies, the policy perceived most important was "expansion of participation in share of shipping company or ships of shipper (0.102)" followed by "strengthening of national shipper-centered service quality (0.101)", and "providing a long-term transportation contract model of container cargo (0.085)". To recover the Korean shipping industry via win-win of ship owners and shipper, the policy enforcement is important through correct government policy establishment and priority selection. In this regard, this study contributed to proposing policies and priority of the policies. For the future study, detailed analysis on comparison of perception difference among stakeholders in the shipping industry is needed.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.6
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• pp.481-495
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• 2020

After the resonator on the basis of the wave-filter theory was designed to control the waves with a specific frequency range surging into the harbor, the several case with the use of resonator have been reported in some part of sea, including the port of Long Beach, USA, and yacht harbor at Rome, Italy in order to control the long-period wave motion from the vessels. Recently, the utility and applicability of the resonator has been sufficiently verified in respect of the control of tsunami approximated as the solitary wave and/or the super long-period waves. However, the case with the application of tsunami in the real sea have not been reported yet. In this research, the respective case with the use of existing resonator at the port of Mukho and Imwon located in the eastern coast of South Korea were studied by using the numerical analysis through the COMCOT model adapting the reduction rate of 1983 Central East Sea tsunami and 1993 Hokkaido Southwest off tsunami. Consequently, the effectiveness of resonator against tsunami in the real sea was confirmed through the reduction rate of maximum 40~50% at the port of Mukho, and maximum 21% at the port of Imwom, respectively. In addition, it was concluded that it is necessary to study about the various case with application of different shape, arrangement, and size of resonator in order to design the optimal resonator considering the site condition.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.3
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• pp.137-149
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• 2021

Cable-stayed bridges are infrastructure facilities of a highly public nature; therefore, it is essential to ensure operational safety and prompt response in the event of a collapse or damage caused by natural and social disasters. Among social disasters, impact accidents can occur in bridges when a vehicle collides with a pier or when crashes occur due to aircraft defects. In the case of offshore bridges, ship collisions will occur at the bottom of the pylon. In this research, a procedure to evaluate the structural behavior of a cable-stayed bridge for aircraft impact is suggested based on a numerical analysis approach, and the feasibility of the procedure is demonstrated by performing an example assessment. The suggested procedure includes 1) setting up suitable aircraft impact hazard scenarios, 2) structural modeling considering the complex behavior mechanisms of cable-stayed bridges, and 3) structural behavior evaluation of cable-stayed bridges using numerical impact simulation. It was observed that the scenario set in this study did not significantly affect the target bridge. However, if impact analysis is performed through various scenarios in the future, the load position and critical load level to cause serious damage to the bridge could be identified. The scenario-based assessment process employed in this study is expected to facilitate the evaluation of bridge structures under aircraft impact in both existing bridges and future designs.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.4
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• pp.550-556
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• 2021

The scissor-type rope cutter is the most widely used amongst all kinds of commercially available rope cutters in Korea. In this study, we performed finite element analysis on the scissor-type rope cutter. We determined the structure of the cutter that would ensure its stable operation in various situations involving rope entanglement, and verified its effectiveness by testing it in the lab and in an actual ship. These investigations revealed that when the propeller shaft was not rotated by rope entanglement, the constant torque generated by the engine resulted in the torsion of the rope cutter and maximum deformation in the lower blade, which was not restricted by finite element analysis. With increasing blade thickness, the maximum values of deformation and equivalent stress decreased, resulting in a rise in the safety factor. At the constant blade thickness, the effect of the torque variations on the maximum equivalent stress and the maximum deformation is independent of the position of the external force of the rope cutter and decreases in direct proportion. The results of this study confirmed that the rope-cutter structure determined by analysis could lead to a hassle-free removal of ropes and fishing nets under all conditions and environments.