• Proceedings of the Korea Port Economic Association Conference
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• 2006.08a
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• pp.277-290
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• 2006

A shipping operation broadly breaks down into: the acquisition of the ship, securing income from the ships, operating the ships, and running the business. For all ships these functions have to be performed. But most important thing is whether it is a better option for some or all these activities to be undertaken by a third party manager rather than resource them in-house or not. However, the size of ship management market has been increasing continuously over the last decades to achieve cost-savings. The ship management is considered as creating high added value and contributing to national economic growth. This paper will analyzes development trends of ship management and market, and carry out comparative studies with Korean ship management companies and an empirical studies on selection criteria of ship management firms. In doing so, some implications and alternatives will be suggested in order for Korean ship management companies to create high added value and gain international competitive edge.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.3
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• pp.580-594
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• 2015

Liquid sloshing in two-dimensional (2-D) and three-dimensional (3-D) rectangular tanks is simulated by using a level set method based on the finite volume method. In order to examine the effect of natural frequency modes on liquid sloshing, we considered a wide range of frequency ratios ($0.5{\leq}fr{\leq}3.2$). The frequency ratio is defined by the ratio of the excitation frequency to the natural frequency of the fluid, and covers natural frequency modes from 1 to 5. When fr = 1, which corresponds to the first mode of the natural frequency, strong liquid sloshing reveals roof impact, and significant forces are generated by the liquid in the tank. The liquid flows are mainly unidirectional. Thus, the strong bulk motion of the fluid contributes to a higher elevation of the free surface. However, at fr = 2, the sloshing is considerably suppressed, resulting in a calm wave with relatively lower elevation of the free surface, since the waves undergo destructive interference. At fr = 2, the lower peak of the free surface elevation occurs. At higher modes of $fr_3$, $fr_4$, and $fr_5$, the free surface reveals irregular deformation with nonlinear waves in every case. However, the deformation of the free surface becomes weaker at higher natural frequency modes. Finally, 3-D simulations confirm our 2-D results.

• The Journal of the Acoustical Society of Korea
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• v.40 no.4
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• pp.370-381
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• 2021

This paper presented an efficient transceiver structure of multiband Frequency Shift Keying (FSK) signals with direct sequence spread spectrum for maintaining covertness and performance. In aspect to covertness, direct sequence spread spectrum method, which multiplying by Pseudo Noise (PN) codes whose rate is much higher than that of data sequence, is employed. In aspect to performance, in order to overcome performance degradation caused by multipath and Doppler spreading, we applied multiband, turbo equalization, and weighting algorithm are applied. Based on the simulation results, by applying 4 number of multiband and number of chips are 8 and 32, experiments were conducted in a lake with a distance of moving from 300 m to 500 m between the transceivers. we confirmed that the performance was improved as the number of bands and chips are increased. Furthermore, the performance of multiband was improved when the proposed weighting algorithm was applied.

• Journal of Korea Port Economic Association
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• v.36 no.4
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• pp.31-52
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• 2020

The increase in the number of ships entering and leaving the port and the creation of various cargo volumes can promote local economy and lead to regional development, attracting businesses, and influx of local residents. The port area of Dangjin consists of the limited cargo and most private docks, making it increasingly weak in meeting the local economic development and the expectations of local residents. Therefore, in order to promote regional development and revitalize the local economy, and to reduce the sense of alienation of local residents, it is necessary to make it easier to access and water to ports through the development of all areas of Eumseompo-gu, and to make active changes in the marine and port logistics environment. As seen through various cases of port development at home and abroad and the redevelopment of the ports at Gohyeon Port in Geoje, Dangjin Port should be able to quickly demonstrate the development of the Dangjin Port area and improve the quality of life for the residents of the metropolitan area. This is the time when the government's drive is highly requested.

• Journal of the Korea Convergence Society
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• v.10 no.1
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• pp.177-186
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• 2019

The purpose of this study is to examine the trend of export growth rate and rate of change by each port/airport in Korea. And to analyze which each port/airport are showing a high growth rate. To this end, Incheon Airport, Busan, Incheon, Ulsan, Gwangyang and Pyeongtaek were selected in order of export value. The analysis period for each port/airport was 200 monthly data from September 2001 to April 2018. Pyeongtaek, Incheon and Gwangyang are relatively larger than Busan and Ulsan in the rate of increase and change. This is because export to China and Southeast Asia has increased more than in the US and Japan. As a result of the analysis, exports from Busan, Incheon Airport and Ulsan have recently been shifted to Incheon Airport, Incheon, Gwangyang and Pyeongtaek. In addition, the export portion of Incheon International Airport, which is an aviation logistics service, is growing more and more. In the west coast era, interest and investment in Incheon, Pyeongtaek and Gwangyang seem to be more needed in preparation for import and export to China, Southeast Asia and North Korea.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.7
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• pp.960-966
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• 2018

Communication antennas used at sea have been developed remarkably. However, the speed of this development is insufficient when compared with user demands. Therefore, we developed an antenna for UWB/Bluetooth that operates on 3 [GHz] and 5.72 [GHz] bands in order to use the high-speed communication network system which improved antenna miniaturization, gain and radiation patterns. To improve bandwidth, a microstrip patch antenna was selected and CST Microwave Studio 2014 program was used. Through the program, we calculated the slot width, length, transmission line width, etc. using a theoretical formula at each step. These figures were checked through simulation to see if they meet production standards. UWB for high-speed wireless communication for short-range communication at sea, Bluetooth for exchanging information at a short distance by connecting each device, and corresponding technology can be easily utilized.

• Acta Via Serica
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• v.4 no.1
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• pp.87-109
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• 2019

In the Iranian epic $K{\bar{u}}shn{\bar{a}}ma$, there is a rather interesting story that recounts how the inhabitants of $B.s{\bar{i}}l\bar{a}$ cross-breed their domesticated horses with a magical horse living in the sea in order to obtain fine-bred ones. What is even more interesting is that similar accounts are also seen in many of other classical Perso-Arabic works and Chinese sources. The regions that such events took place in mainly spread over Central Asia and western China while in $K{\bar{u}}shn{\bar{a}}ma$, the story happens in $B.s{\bar{i}}l\bar{a}$, a legendary kingdom with its historical prototype being Silla. By sorting out certain records of how ancient people sought fine horses by cross-breeding domesticated horses with wild horses that inhabited mountains and waters within Chinese sources and classical Muslim works, and comparing these accounts with similar plot lines as depicted in $K{\bar{u}}shn{\bar{a}}ma$, this paper attempts to elucidate that the story in $K{\bar{u}}shn{\bar{a}}ma$ is a result of flourishing land and maritime exchanges between East Asia and West Asia during ancient and medieval times, rather than a purely literary fiction. It was not only influenced by the horse culture that thrived over the Eurasian Steppe, but the story is also coincidentally in accordance with the fact that the nomadic zone which lies within the central Eurasian continent extends as far as the Korean Peninsula in northeast Asia.

• Journal of Ocean Engineering and Technology
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• v.33 no.4
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• pp.340-349
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• 2019

In the case of a fire accident on a ship or an offshore plant, the design of the bulkhead penetration piece must be verified via a fire test procedure (FTP), as specified by the Maritime Safety Committee (MSC). The purpose of this study is to verify both the numerical analysis results and the design specifications for penetration pieces that could be applied to the A60 class bulkhead division. In this study, the FTP was carried out in accordance with the test procedure prescribed in the MSC regulation. In order to review the fire resistance performance according to the material type, bulkhead penetration pieces for the FTP were made from brass, carbon steel for machine structures (S45C), and austenite stainless steel (SUS316). In addition, spray-type insulation and mechanical fastener-type insulation were applied to investigate the fire resistance performance according to the type of insulation. To verify the heat transfer numerical analysis results for the A60 class bulkhead penetrating piece from this test study, the design specifications of the penetrating piece material and the insulation type applicable to a ship and an offshore plant were identified.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.233-239
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• 2019

An unmanned underwater vehicle is a major weapon system that allows surveillance and reconnaissance missions in border areas or threatening areas where enemy submarines are present. Unmanned underwater vehicles can be used to explore underwater resources, predict disasters, and survey the topography of the ocean floor in the civilian fields, while in the defense fields, it can be used for anti-submarine reconnaissance and mine countermeasures. In this paper, we first investigate the main classification of unmanned underwater vehicles, and foreign R&D trends are analyzed based on the main classification criteria by weight, such as portable, light, heavy and large-scale unmanned underwater vehicles. Then we examine the trends in the development of domestic unmanned underwater vehicles. Finally, through the analysis of both domestic and foreign unmanned underwater vehicles, we present future development trends of unmanned underwater vehicles in order to set defense goals to counter the anticipated threats and diversified potential environment.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.1
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• pp.111-116
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• 2019

The fire detectors used in the engine rooms of ships offer only a slow response to emergencies because smoke or heat must reach detectors installed on ceilings, but the air flow in engine rooms can be very fluid depending on the use of equipment. In order to overcome these disadvantages, much research on video-based fire detection has been conducted in recent years. Video-based fire detection is effective for initial detection of fire because it is not affected by air flow and transmission speed is fast. In this paper, experiments were performed using images of smoke from a smoke generator in an engine room. Data generated using LBP and GLCM operators that extract the textural features of smoke was classified using SVM, which is a machine learning classifier. Even if smoke did not rise to the ceiling, where detectors were installed, smoke detection was confirmed using the image-based technique.