• Journal of Advanced Navigation Technology
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• v.23 no.4
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• pp.296-301
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• 2019

Artificial intelligence is closely linked to our real lives, leading innovation in various fields. Especially, as a means of transportation possessing artificial intelligence, autonomous unmanned vehicles are actively researched and are expected to be put into practical use soon. Autonomous cars and autonomous unmanned aerial vehicles are required to equip accurate navigation system so that they can find out their present position and move to their destination. At present, the navigation of transportation that we operate is mostly dependent on GPS. However, GPS is vulnerable to external intereference. In fact, since 2010, North Korea has jammed GPS several times, causing serious disruptions to mobile communications and aircraft operations. Therefore, in order to ensure safety in the operation of the autonomous unmanned vehicles and to prevent serious accidents caused by the intereference, rapid situation judgment and countermeasure are required. In this paper, based on big data and machine learning technology, we propose a countermeasure system for GPS interference that supports decision making by applying John Boyd's OODA loop cycle (detection - direction setting - determination - action).

• Journal of Space Technology and Applications
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• v.2 no.2
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• pp.121-136
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• 2022

Automatic Identification System used in ship communication is required for marine control way, including monitoring of vessel operation in coastal and exchanging of information for safety navigation between them. But, it uses a very high frequency band of approximately 160 MHz, and at the same time, due to the curvature of Earth, there is a limit to the communication distance. Several demonstrations were made successfully over satellite, but not much work has been done yet through cube-satellite which has low-orbit at 500 km altitude. Here, we demonstrate a reception test of AIS (automatic identification system) receiver for a cube-satellites using software-defined radio (SDR). We collected AIS data from ship at port of Busan, Korea, using R8202T2 SDR and established to transmit them using Adam-Pluto and Matlab Simulink. The process of weakening the signal strength to a satellite was constructed using attenuator. Through above process, we demonstrated whether AIS data was successfully received from the AIS payload.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2021.11a
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• pp.3-4
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• 2021

Korea government has developed Korean e-Navigation service to assist ship's collision avoidance, and is providing it since Jan. 2021 to korean vessels to reduce marine accidents caused by human error which is regarded as main reason of marine accidents. It is a huge achievement itself because it is a real-time maritime safety information service based on digital communication, but still has room for improvement to provide customized information for each vessel, such as considering ship's characteristics. This research analyzes current status and requirement of collision avoidance assistance service. Lastly, it suggests direction of improvement of service such as using data science, artificial intelligence(AI).

• The Korean Journal of Air & Space Law and Policy
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• v.33 no.2
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• pp.367-418
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• 2018

Just as safety is the most important thing in aviation, safety is the most important in the operation of unmanned aircraft (RPA), and safety operation is the most important in the legal responsibility of the operator of the unmanned aircraft. In this thesis, the legal responsibility of the operator of the unmanned aircraft, focusing on the responsibility of the operator of the unmanned aircraft, was discussed in depth with the issue of insurance, which compensates for damages in the event of an accident First of all, the legal responsibility of the operator of the unmanned aircraft was reviewed for the most basic : definition, scope and qualification of the operator of the unmanned aircraft, and the liability of the operator of the Convention On International Civil Aviation, the ICAO Annex, the RPAS Manual, the Rome Convention, other major international treaties and Domestic law such as the Aviation Safety Act. The ICAO requires that unmanned aircraft be operated in such a manner as to minimize hazards to persons, property or other aircraft as a major principle of the operation of unmanned aircraft, which is ultimately equivalent to manned aircraft Considering that most accidents involving unmanned aircrafts fall to the ground, causing damage to third parties' lives or property, this thesis focused on the responsibility of operators under the international treaty, and the responsibility of third parties for air transport by Domestic Commercial Act, as well as the liability for compensation. In relation to the Rome Convention, the Rome Convention 1952 detailed the responsibilities of the operator. Although it has yet to come into effect regarding liability, some EU countries are following the limit of responsibility under the Rome Convention 2009. Korea has yet to sign any Rome Convention, but Commercial Act Part VI Carriage by Air is modeled on the Rome Convention 1978 in terms of compensation. This thesis also looked at security-related responsibilities and the responsibility for privacy infringement. which are most problematic due to the legal responsibilities of operating unmanned aircraft. Concerning insurance, this thesis looked at the trends of mandatory aviation insurance coverage around the world and the corresponding regulatory status of major countries to see the applicability of unmanned aircraft. It also looked at the current clauses of the Domestic Aviation Business Act that make insurance mandatory, and the ultra-light flight equipment insurance policy and problems. In sum, the operator of an unmanned aircraft will be legally responsible for operating the unmanned aircraft safely so that it does not pose a risk to people, property or other aircraft, and there will be adequate compensation in the event of an accident, and legal systems such as insurance systems should be prepared to do so.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.197-207
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• 2021

According to the analysis of Kolb's learning style, Korean university student pilots interpret and attach meaning to themselves. Moreover, as the school year progresses, they enter the flight-training course with a 100 % diverger style, which is a variety of thoughts and imaginative learning styles. As the school year progresses, some changes occur with accommodator (11.1%) and assimilator (15.9%) styles. On the other hand, most students remain as the diverger style (71.4%). In the case of U.S. student pilots, most in first-year are assimilator (35.5%) and converger (24.3%) styles, and the proportion of the converger style increases as the senior year is approached. In the first grade, most Chinese student pilots are assimilators (41.5%) and convergers (28.4%), but in the higher grade, the proportion of assimilators and convergers decrease, and the proportion of diverger styles increases dramatically. In the fourth grade, the accommodator was similar to the first grade, but the converger style continued to decrease (41.5% in the first grade and 27.0% in the fourth grade).

• Journal of the Korean Society of Marine Environment & Safety
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• v.11 no.2 s.23
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• pp.33-40
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• 2005

According to the development of technology of the navigational equipments, many bridge equipments have been improved, however, marine accidents by human error have not been reduced. Therefore, a matter of primary concern is focused on whether bridge equipments of ships are ergonomically arranged to reduce errors due to human factors. As part of a design of IBS(Integrated Bridge System) standard, rules of the conning display to save time and additional movements to obtain important informations of a ship should be established as soon as possible. In the present study, ergonomic design factors for the conning display are studied through the survey of related works, heuristic evaluations, sketch method tests as well as questionnaires. Using these factors, new conning display was designed and the ergonomic indices were evaluated by comparing tests of the existing conning displays. It is found that the designed conning display obtained high ergonomic index showed better performance, therefore, the ergonomic index studied in the present paper can be used as a useful design standard in the conning display design procedures.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.5
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• pp.554-563
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• 2016

Ships are capable of operating on residual fuel oil. Recently, various attempts have been made to meet environmental regulations and with ships operating on residual fuel oil. One way of fulfilling these requirements is by using fuel additives. Dispersants and fuel combustion improvers will have a positive effect on improving the combustion characteristics of the residual fuel oil. As such, this study examines fuel oils blended with additives by using fuel combustion analysis (FIA/FCA) and thermogravimetric analysis (TGA). The results of FIA/FCA focuse only on the amount of work done by the fuel oil. Therefore, it is recommended in this study that a new method to evaluate the combustion efficiency via FIA/FCA processes be developed. The analysis with ROHR curve gained by FIA/FCA brought similar results with pressure trace curve therefore it can be said that new analysis method can be reliable. The TGA, analysis process is very sensitive to the evaporation of fuel, for example, which could be addressed. In the performance-related findings of this study, blended samples with additives containing iron compounds showed a greater improvement in early combustion characteristics than samples without additives.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.5
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• pp.547-553
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• 2016

Black carbon (BC) contained in particulate matter (PM) originating from the exhaust gases of ships' diesel engines has been receiving great attention as a cause of glacial melting and warming in the polar regions. In this study, we took samples from various locations of PM emitted from the training ship (T/S) HANBADA's main engine, in cooperation with the Korea Maritime and Ocean University. We analyzed the structure and characteristics of these samples using high-resolution transmission electron microscopy (HR-TEM) and applied our findings as fundamental research for developing PM reduction technology. We also employed our results to determine appropriate preemptive action to meet upcoming PM/BC regulations. In addition, we confirmed the emission trend of pollutants from exhaust gases under various engine operating conditions using an exhaust gas analyzer. Results obtained from the analysis of HR-TEM images showed that the structure of the PM is chain-like wispy agglomerates consisting of a number of individual spherical particles. As the sampling location was moved away from the turbo charger (T/C) towards the funnel, more condensates were observed at a low temperature and the molecular structure of the PM lost its characteristic BC structure as an amorphous structure gradually appeared. Furthermore, through the analysis of exhaust gases, we predicted a decrease in PM concentration in the exhaust stream as engine rpm increase.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.6
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• pp.810-817
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• 2018

In Korea, tuna purse seine fishery is the industry with the highest production volume in domestic deep-sea fishery. Research has been continuously carried out since the late 1980s, and research on modernization of technology has been actively conducted. However, while auxiliary works boats on the fishing vessels play an important role in the purse seine fishing, related research is not sufficient. In this study, we tried to rebuild the propulsion system of the Net-boat from the propeller to the waterjet type and to perform the hull form conversion to improve the resistance performance of the hull part and improve the motion performance. For this, we calculated the change of the fluid performance of the ship through computational numerical analysis. In addition, towing tank tests were carried out to verify the performance of the existing ship and the ship which changed the propulsion system. As a result, resistance performance of the waterjet type compared to the propeller type was improved by approximately 45 %. It was confirmed that this was due to reduction of the wetted surface area by removing net and improvements in hull form.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.2
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• pp.267-274
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• 2018

A variety of appendages are attached to coastal and offshore fishing boats to improve stability during navigation or fishing operations (stability performance and roll reduction). These appendages are generally classified into three types, which are shown in Fig. 1. The numerical calculations were conducted for the following eight cases: one case of a bare hull, three cases where a single appendage attached, three cases of a pair of appendages attached, and one case where all three appendages were attached. Table 1 presents the main dimensions of the bare hull and Table 2 describes the main dimensions of the three appendages. The fluid dynamic performance with regard to the three hull appendages was evaluated via CFD for the following cases: each of the appendages attached independently, a pair of appendages attached, and all three appendages attached simultaneously. The No. 1 appendage showed that pressure resistance was proportionally greater than friction resistances. Both Nos. 2 and 3 appendages showed comparable levels of pressure and friction resistances. The correlation between appendages was minimal in the case of pairs and Comparing the cases of the No. 2 appendage attached and all appendages attached, at 11 kn, the EHP showed an difference of 9 %.