• Journal of Advanced Navigation Technology
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• v.26 no.5
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• pp.272-280
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• 2022

An aircraft carrier is a combat ship that acts as an aircraft base at sea and performs combat through aircraft mounted as a military ship operating the aircraft. The Navy proposed a 40,000-ton light aircraft carrier operation plan that could be equipped with vertical takeoff and landing fighter jets and helicopters around 2033, and based on this, this study examined the operation of aircraft control equipment among the aviation support systems required for operating light aircraft carriers in Korea. PriFly, TWR's ILARTS, ILM for airspace control, ASR, PAR, LAAS or RNAV, PALS (JPALS) for access control are required as essential equipment, and communication network and SCATT-16 are required along with URN-25 TACAN, ICLS (El/Az), ACLS OLS, MOVAS, IFLOLS, etc. This study consists of two parts, and part 2 will describe a specific control method on an aircraft carrier.

• Journal of Digital Convergence
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• v.18 no.12
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• pp.195-204
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• 2020

The purpose of this study is to look for the relationship between export weight and control volume, inland cargo, export cargo transport, ship departure. The analysis period were used for a total of 113 monthly data from January 2011 to May 2020. Data were retrieved from the Korean Statistical Information Service of the Statistics Korea. The data used in this study were performed numerical analysis, index analysis and model analysis using the rate of change from the same month of the previous year. In the trend of the increase rate, the amount of control has plummeted from 150% to 60% due to the influence of Corona 19 in the beginning of 2020. At the same time, export weight and export cargo transport also decreased. As a result of the analysis, export weight showed relatively high synchronization with export cargo transport and control volume. On the other hand, export weight and inland cargo showed relatively low synchronization. Export weight is expected to continue in 2020 after the fluctuation rate began to decrease after 2019. If we can find the point of rebound in control volume or export cargo transport in the future, we can predict the point of increase in export weight. We expect to see an increase in export weight as soon as possible.

• Journal of Navigation and Port Research
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• v.28 no.1
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• pp.9-16
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• 2004

The purpose of this study is to examine the algorithm of ship collision avoidance system and to improve its performance. The study on the algorithm of ship collision avoidance system have been carried out by many researchers. We can divide the study according to the adopted theory into two category such as 'collision risk calculation method' and 'risk area method'. It is not so difficult to find heir merit and demerit in the respective method. This study suggested newly modified model, which can overcome a limit in the two method. The suggested model is based on collision risk calculation method and suggests how to solve the threshold value problem, that is, one of the unsolved issues in collision risk calculation method. To solve that problem this study proposed new system under which the users can select appropriate threshold value according to environments such as traffic situations and weathers conditions. Simulation results of new model is schematized using 'risk area method'to examine the relationships between the two method. In addition, in case of 'collision risk method', when TCPA and DCPA are used to determine collision risk, a problem happens, that is, two ships become too close in their stem area, therefore, partial function of 'risk area method'is adopted to solve the problem in suggested model.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.2
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• pp.139-145
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• 2017

Recently, gusts, typhoon and tsunamis have been occurring more frequently around the world. In such an emergency situation, a moored vessel can be used to predict and analyze other vessel behavior, but if the mooring system is destroyed, marine casualties can occur. Therefore, it is necessary to determine quantitatively whether a vessel should be kept in the harbour or evacuate. In this study, moored ship safety in an exclusive wharf according to swell effects on motion and mooring load have been investigated using numerical simulations. The maximum tension exerted on mooring lines exceeded the Safety Working Load for intervals 12 and 15 seconds. The maximum bollard force also exceeded 35 tons (allowable force) in all evaluation cases. The surge motion criteria result for safe working conditions exceeded 3 meters more than the wave period 12 seconds with a wind speed of 25 knots. As a result, a risk rating matrix (risk category- very high risk, high risk and moderate risk) was developed with reference to major external forces such as wind force, wave height and wave periods to provide criteria for determining the control of capabilities of mooring systems to prevent accidents.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.7
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• pp.927-935
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• 2019

Screw-failure accidents in small ships frequently occur in coastal waters. In particular, vessels' propulsion systems are frequently coiled due to objects such as fish-nets and ropes that float on the sea. The failure of the ship's propulsion system can cause primary accidents such as ship operation delays and drifting due to loss of power; furthermore, the possibility of secondary accidents such as those involving operators in the underwater removal of rope stuck in a propeller. Ships that do not have the proper tools to solve these problems must be either lifted onto land to be repaired or divers must dive directly under the ship to solve the problem. Accordingly, some small vessels have been equipped with rope-cutter devices on the propeller shaft to prevent ship propeller system accidents in recent years; however, they are not being applied efficiently due to the cost and time of installation. To solve these problems, this study develops an underwater rope-cutter device and controller for the removal of propeller and shaft foreign material in small vessels. This device has simple structures that use the principle of a saw. Meteor gears and crank pins were used for the straight-line rotation of saw blades of the underwater rope-cutters to allow for long strokes. Furthermore, the underwater rope-cutting machines can be operated by being connected to the ship battery. The user, a non-professional, can ensure convenience and stability by applying reverse current prevention and a speed control circuit so that it can be used more conveniently and safely.

• Journal of Advanced Marine Engineering and Technology
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• v.20 no.3
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• pp.137-143
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• 1996

The propulsion marine diesel engine has been widely applied with a mechanical-hydraulic governor to control the ship speed for long time. But it was recently very difficult for the mechanical-hydraullic governor to control the speed of engine under the condition of low speed and low load because of jiggling and hunting by rough fluctuation of rotating torque. To solve these problems of control systems, the performance improvement of mechanical-hydraulic governor is required. In this paper, in order to analyze the speed stability of control systems, the influence of parameters of the engine dead time, gain, damping ratio was discussed on the view of control engineering. The performance improvement of a conventional mechanical hydraulic governor is confirmed to be possible by fuzzy control scheme.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.2
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• pp.193-201
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• 2014

This study provided safe sailing speed and appropriate passing time to areas of known strong current water to prevent marine accident of the ships. To the interpretation of these data which target Myeongnyang waterway, AIS data of the ship was collected from $12^{th}$ July to $15^{th}$ July 2010 and site environment was investigated on $4^{th}$ September 2010. On the basis of the collected data, the 'Minimum Navigation Speed' and 'Optimum Navigation Speed' were calculated. It has also considered the 'Spare control force' or allowance and the 'Respond Rudder Angle' for each tidal current speed. Additionally, it suggested the safe passing time to strong current area by analyzing tidal level and tidal current speed. The conclusion of the research are as follows : (1) If the flow rate is greater than 4.4 kn, it is difficult for the model ship to control herself by her own steering power and to cope with tidal current pressure force and yaw moment caused by the tidal current.. (2) The minimum navigation speed should be over 2.3 times the tidal current and the optimum navigation speed should be over 4.0 times the tidal current. (3) When spring tide, the optimum passing time at Myeongnyang waterway is between 30 minutes to 1 hour before the time of high/low water, and at 5 hours after high/low water, passing of ships should be avoided because it is time when the flow rate is over 4 kn.

• Journal of Navigation and Port Research
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• v.30 no.9
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• pp.735-740
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• 2006

Marine officers should have crisis control ability because ship operation needs not only highly specialized information, but also functional capability due to the fact that there always exist dangers at sea, which are different from those at shore. Therefore, marine officers should be trained on the related specialized information under the systematical educational system including shipboard training. Their training is also based on the strong spiritual power and physical strength through the strict training process. In order to have these vocational personalities, dormitory life training and shipboard training courses seem to be essential processes, which are required of maritime education. The introduction of automatic system into the ship as a result of the recent development of technology brings decrease of the full number of crew. Consequently, marine officers are increasingly under heavy burden, and should have more ship operation capabilities than before. Maine officers should have not only specialized information which differs from that at shore, but also vocational adaptability which can reasonably tackle with all the problems which exist on the spot and are obstacles to individual, spiritual, physical, natural, and social demands. So it is required that marine officers should have study many areas to deal with as extra curricula besides their major field of study, which are unique characteristics of the education for them. These vocational adaptabilities are based on the spiritual characteristics, such as self-developmental education, responsibility, meticulous care, attentiveness, voluntary, planning, readiness, spontaneity, accuracy, self-denial, obedience, leadership, and etc.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.1
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• pp.64-69
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• 2014

There are 440V and 220V electric source in ship. A 440V source is used to drive the power system such as crane and winch on deck and pump in engine room, and a 220V source is used to drive the power source for residential zones, control devices in engine room. In this paper, we made single phase inverter system for grid connection with 220V source for ship, and analyzed THD(Total harmonic distortion) by variation of parameters of L-C low pass filter and deadtime of inverter switching.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.8
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• pp.91-98
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• 2010

The Korean navy has been using the ICS(Integrated Communication System) to transfer a command, control and information on the naval ship. The major equipment for the ICS has been imported from abroad, so that there were some problems such as lack of logistics support, leaking military secrets. This paper describes considerations for the development and the key technology of the domestic ICS which is developed to solve the problems mentioned above and to integrate various future communication elements on the naval ship.