• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.2
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• pp.184-193
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• 2024

Harbor and Fishery Design Criteria defines that ship routing should be designed to ensure safe ship navigation and easy maneuvering. The design of the channel width is one of the critical conditions in routeing of ships. For the criteria of the channel width, qualitative evaluation criteria are used in South Korea, whereas quantitative evaluation criteria are used in other countries. Environmental factors, such as winds, tidal currents, and waves directly or indirectly affect ship resistance when sailing. Depending on their strength the environmental factors may pose a threat to the safe navigation of ships. Thus, vessel traffic control was regulated in South Korea according to the Beaufort scale. In order to design the channel width to reflect the environmental factors closely related to the safe navigation of ships, quantitative evaluation criteria reflected with environmental factors were presented in other countries, however, these external factors were not considered in South Korea. This study analyzed the relationship between the channel width actually used by ships and environmental factors by using the trajectories of ships entering and leaving Mokpo Port. This study also suggested the required channel width according to tidal currents and compared it with the channel width design criteria of other countries.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.3
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• pp.411-418
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• 2017

In the domestic case, although technological capabilities are recognized globally in the IT field, it is actually that the technical capabilities of the domestic leisure ship market which is formed mainly by fishing vessels are not beyond their technical capabilities At the point where the GNP of our country already goes over 22,000 dollars, the demand for the products related to the middle and small leisure boats is gradually increasing, but most of the high added value products depend on the imports from U.S.A. and Europe. And in case of the cars, with the Car Navigation as the start, products which satisfies various demands of the users are coming out in large quantity and now the IT technology is the necessity which can not be lived without in the car industry. Thus, if the digital ship navigator which jointed the recent ICT technology which was applied to the land for the domestic middle and small leisure ships by utilizing the embedded hardware technology and mapping technology which are credible is developed and distributed, it will become not only the opportunity to improve the industry related to middle and small ship IT, but also, the export about overseas market can be expected.

• Journal of Internet Computing and Services
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• v.21 no.4
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• pp.117-126
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• 2020

A maritime object detection system is an intelligent assistance system to maritime autonomous surface ship(MASS). It detects automatically floating debris, which has a clash risk with objects in the surrounding water and used to be checked by a captain with a naked eye, at a similar level of accuracy to the human check method. It is used to detect objects around a ship. In the past, they were detected with information gathered from radars or sonar devices. With the development of artificial intelligence technology, intelligent CCTV installed in a ship are used to detect various types of floating debris on the course of sailing. If the speed of processing video data slows down due to the various requirements and complexity of MASS, however, there is no guarantee for safety as well as smooth service support. Trying to solve this issue, this study conducted research on the minimization of computation volumes for video data and the increased speed of data processing to detect maritime objects. Unlike previous studies that used the Hough transform algorithm to find the horizon and secure the areas of interest for the concerned objects, the present study proposed a new method of optimizing a binarization algorithm and finding areas whose locations were similar to actual objects in order to improve the speed. A maritime object detection system was materialized based on deep learning CNN to demonstrate the usefulness of the proposed method and assess the performance of the algorithm. The proposed algorithm performed at a speed that was 4 times faster than the old method while keeping the detection accuracy of the old method.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.35 no.6
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• pp.527-534
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• 2017

The purpose of this study is to develop unmanned equipment that can automatically move to the desired point and measure water quality at the correct depth. For this purpose, we constructed a water sampling lift and water sampling container, an unmanned vessel equipped with a VRS-GPS, an acoustic echo sounder, and a water quality sensor. Also, we developed an automatic navigation algorithm and program, an automatic water sampling program, and a water quality map generation program. As a result of the experiment in the detention pond, the unmanned vessel sailed along the planned route with an accuracy of about 93% within the error range of 3m. In addition, the water quality sensor installed in the lift was able to acquire the water quality of the target area in real time and transmit it to the server via wireless Internet, and it was possible to monitor the water quality of each site in real time. Through field experiments, the water sampling lift was able to control the desired length with an accuracy of about 94%. The stretch length accuracy experiment of the water sampling lift was impossible to measure directly in the water, so it was replaced land-based experiment. We also found some unstable problems due to the weight of the water sampling lift and the weight of the air compressor to operate the water container. Except these two problems, we accomplished purpose of this study. An automated water quality measurement method using an unmanned vessel can be used to measure the quality of water in a difficult to access area and to secure the safety of the worker.

• Journal of Navigation and Port Research
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• v.40 no.6
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• pp.353-360
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• 2016

The International Maritime Organization (IMO) has issued international standards for ship maneuverability and stability. These have been established to improve marine safety and influence the direction of research. The previous literature has been researched, but there are few studies on the relationship between ship maneuverability and stability. This study carried out a fundamental experiment to quantitatively evaluate that relationship. Radius of turn and maximum heel angle depending on changing were analyzed through a turning test using a free running model ship. The test results show the change tendency of decreasing turn radius and increasng maximum heel angle according to a GM decrease. A rough estimate equation is proposed to predict the change tendency on radius of turn and angle of maximum heel as GM decreases. Many ships can suddenly experience reduced GM due to unexpected reasons during sailing. The results in this study can be used as fundamental data to estimate a ship's tactical turn diameter and variable heel angle for steering as GM decreases.

• Asian Journal of Atmospheric Environment
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• v.9 no.4
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• pp.280-287
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• 2015

The high time-resolution monitoring data are essential to estimate rapid changes in chemical compositions, concentrations, formation mechanisms, and likely sources of atmospheric particulate matter (PM). In this study, $PM_{2.5}$ sulfate, $PM_{2.5}$, $PM_{10}$, and the number concentration of size-resolved PMs were monitored in Fukuoka, Japan by good time-resolved methods during the springtime. The highest monthly average $PM_{2.5}$ sulfate was found in May ($8.85{\mu}g\;m^{-3}$), followed by April ($8.36{\mu}g\;m^{-3}$), March ($8.13{\mu}g\;m^{-3}$), and June ($7.22{\mu}g\;m^{-3}$). The cases exceed the Japanese central government's safety standard for $PM_{2.5}$ ($35{\mu}g\;m^{-3}$) reached 10.11% during four months campaign. The fraction of $PM_{2.5}$ sulfate to $PM_{2.5}$ varied from 12.05% to 68.11% with average value of 35.49% throughout the entire period of monitoring. This high proportion of sulfate in $PM_{2.5}$ is an obvious characteristic of the ambient $PM_{2.5}$ in Fukuoka during the springtime. However, the average fraction of $PM_{2.5}$ sulfate to $PM_{2.5}$ in three rain events occurred during our intensive campaign fell right down to 15.53%. Unusually high $PM_{2.5}$ sulfate (> $30{\mu}g\;m^{-3}$) marked on three days were probably affected by the air parcels coming from the Chinese continent, the natural sulfur in the remote marine atmosphere, and a large number of ships sailing on the nearby sea. The theoretical number concentration of $(NH_4)_2SO_4$ in $PM_{0.5-0.3}$ was originally calculated and then compared to $PM_{2.5}$ sulfate. A close resemblance between the diurnal variations of the theoretically calculated number concentration of $(NH_4)_2SO_4$ in $PM_{0.5-0.3}$ and $PM_{2.5}$ sulfate concentration indicates that the secondary formed $(NH_4)_2SO_4$ was the primary form of sulfate in $PM_{2.5}$ during our monitoring period.

• Journal of Navigation and Port Research
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• v.36 no.1
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• pp.21-26
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• 2012

Recently, vessel hijacking by pirates has been a big issue around the world. For example, the hostages of VLCC "SAMHO Dream" were released for a large sum of ransom. On January 20, 2011 "SAMHO Jewelry" succeeded releasing all of the 21 crews on the vessel by attacking the pirates in international waters for the first time since the founding of the Naval Force. Furthermore, the "HANJIN Tianjin" crews evacuated to the Citadel promptly and were rescued by the navy. As hijacking of Korean vessels by pirates is increasing, various safety measures must be implemented. As a matter of fact, the standard for ship's facilities has been partially revised and setting up an evacuation shelter on all vessels sailing dangerous zone has been reinforced. This research aims to discuss crew Citadel installation on vessels intended for long haul. In addition, it will look at measures against potential gas flow in the event of pirate armed attacks and fire outbreak onboard a vessel. It will also assess the optimal number of crew Citadels theoretically. Lastly, the optimal number of shelters in the event of fire outbreak will be discussed based on an FDS simulation.

• Journal of Navigation and Port Research
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• v.43 no.3
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• pp.143-152
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• 2019

In this paper, the towing stability of the LNG bunker barge was estimated. Currently, LNG bunkering barge is being developed for the bunkering of LNG (Liquefied Natural Gas), an eco-friendly energy source. Since the LNG bunkering barge assumes the form of a towed ship connected to the tow line, the towing stability of the LNG bunker barge is crucial f not only for the safety of the LNG bunker barge but also the neighboring sailing vessels. In the initial stages, a numerical code for towing simulation was developed to estimate the towing stability of the LNG bunkering barge. The MMG (Maneuvering Mathematical modeling Group) model was applied to the equations of motion while the empirical formula was applied to the maneuvering coefficients for use in the initial design stage. To validate the developed numerical code, it was compared with published calculation and model test results. Towing simulations were done based on the changing skeg area and the towing position of the LNG bunkering barge using the developed numerical codes. As a result, the suitability of the designed stern skeg area was confirmed.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.05a
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• pp.185-188
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• 2019

In this paper, the towing stability of the LNG bunker barge is estimated. Currently, LNG bunkering barge is being developed as an infrastructure for the bunkering of LNG (Liquefied Natural Gas), an eco-friendly energy source. Since the LNG bunker barge are in the form of towed ship connected to the tow line, the towing stability of the LNG bunker barge is very important for the safety of not only the LNG bunker barge but also the surrounding sailing vessels. The numerical code for towing simulation was developed to estimate the towing stability of the LNG bunker barge at the initial design stage. The MMG(Manoeuvring Mathematical Group) model was applied to the equations of motion and the empirical formula was applied to the maneuvering coefficients so that they could be used in the initial design stage. To validity of the developed numerical code, it was compared with published calculation and model test results. Towing simulations were carried out according to with and without stern skeg of the LNG bunker barge using the developed numerical code. Through the results of the simulations, the appropriateness of the stern skeg area designed was confirmed.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.1
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• pp.26-32
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• 2017

Enlargement and speed-up of a ship and diversification of ship's type have served to greatly increase the importance of marine transport means. It's reported that accident occurrence frequency of collision is high next to engine damage among the ship accident types, and that the accident ratio according to human factors is also high. In addition, ship accidents come to occur caused by complex cause factors rather than a sole cause factor, it is necessary to investigate the cause factors through the written verdict. This study proposed the cause factors of collision ship accident on the basis of human factors in collision ship accident among the written verdicts provided by the Korean Maritime Safety Tribunal, and inquired into the cause factor and effect through the correlation analysis of accident occurrence factors. Also, this study predicted the collision accident through analyzed the major cause factor of the occurrence at the zero minute when collision on the basis of the time taken from the time point of detecting collision of ships to the time point of collision occurrence. This study used commercial software-Statistical Package for Social Sciences (SPSS Ver21.0) to do correlation analysis. For time analysis, this study analyzed the cause factor and time by analyzing the time taken from the time point of detected ships to the time point of collision occurrence on the basis of the written verdicts. The study analysis showed that there were many cases of collision ship accidents occurrence caused by more than two sorts of cause factors, and that the case (zero minute) where there is no time to spare for collision avoidance accounted for 36.1 %, and negligence in guard or surveillance of the other ship, and sailing while drowsy, or drinking was a contributor to an accident. Poor watch keeping is very strong relationship with pool ready for sail.