• New & Renewable Energy
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• v.10 no.3
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• pp.22-30
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• 2014

The isolated self-generating electricity with diesel engine generator has been used in islands far away from main land. It costs high because of increasing oil price, and unsafe to have supplying oil and its related components by ship due to unexpectable marine conditions. Therefore there is the need for the hybrid system of renewable energy like wind or solar energy systems with oil engine generator, which can reduce oil use and extend oil supplying period. In this study, the feasibility of such hybrid system with smart micro grid on the eight islands of Jeon-nam province is surveyed to find good place for the demonstration test of the hybrid system. In each island, 3 wind turbine systems of 10 kW and photovoltaic of 20 kW are tested with already installed diesel engine. The performance and costs of the hybrid system in each island are compared in the given conditions of solar and wind energy potential. As a result of the study, Jung-ma island is recommended for the optimum place to make real field demonstration test of isolated hybrid generating and smart grid systems.

• Journal of Navigation and Port Research
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• v.40 no.4
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• pp.183-188
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• 2016

Many maritime accidents have been caused by human-error including such things as inadequate watch keeping and/or mistakes in ship handling. Also, new navigational equipment has been developed using IT technology to provide various information for safe navigation. Despite these efforts, the reduction of maritime accidents has not occurred to the degree expected because, navigational equipment provides too much information, and this information is not well organized, such that users feel it to be complicated rather than helpful. In this point of view, the method of representation of navigational information is more important than the quantity of that information and research is required on the representation of information to make that information more easily understood and to allow decisions to be made correctly and promptly. In this paper, we adopt Augmented Reality (AR) technologies for the representation of information. AR is a 3D computer graphics technology that blends virtual reality and the real world. Recently, this technology has been widely applied in our daily lives because it can provide information more effectively to users. Therefore, we propose a new concept, a navigational system based on AR technology; we review experimental results from a ship-handling simulator and from an open sea test to verify the efficiency of the proposed system.

• Journal of Navigation and Port Research
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• v.34 no.6
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• pp.405-415
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• 2010

To assess the possible collision risk between Mokpo Harbour Bridge, which is under construction, and passing vessels, we proposed Real-Time Bridge-Vessel Collision Model (RT-BVCM) in this paper. The mathematical model of RT-BVCM consists of the causation probability by the vessel aberrancy due to navigation environments, the geometric probability by the structural feature of a bridge relative to a ship size and, the failure probability by the ship collision track and the stopping distance which is not to come to a stop before hitting the obstacles. Then, the probabilistic mathematical model represented as risk index with the risk level from 1 to 5. The merit of the proposed model to the collision model proposed by AASHTO (American Association of State Highway and Transportation Officials) is that it can provide enough time to take adequate collision avoiding action. Through the simulation tests to the two kinds of test ships, 3,000 GT and 10,000 GT, it is cleary found that the proposed model can be used as a collision evaluation model to the passing vessel and Mokpo Harbour Bridge.

• Korean Management Science Review
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• v.17 no.1
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• pp.41-54
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• 2000

in the real world situations that some jobs need be processed only on certain limited machines frequently occur due to the capacity restrictions of machines such as tools fixtures or material handling equipment. In this paper we consider n-job non-preemptive and m parallel machines scheduling problem having two machines group. The objective function is to minimize the sum of earliness and tardiness with different release times and due dates. The problem is formulated as a mixed integer programming problem. The problem is proved to be Np-complete. Thus a heuristic is developed to solve this problem. To illustrate its suitability and efficiency a proposed heuristic is compared with a genetic algorithm and tabu search for a large number of randomly generated test problems in ship engine assembly shop. Through the experimental results it is showed that the proposed algorithm yields good solutions efficiently.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.546-551
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• 2020

Generally, surface vessels have many compartments for operation and living quarters, and each compartment is an important space for the ship's survivability. During ship construction, a compartment leak test is necessary and is carried out on each vessel. However, the current test method is in doubt when looking at the actual test results. The reason is that only one pressure gauge is used for the measurement to check the air, so an uncomprehended phenomenon is detected during group compartment leak tests. From this point of view, an improved test device and method are needed. In this study, a multi-channel data acquisition device with multiple pressure sensors is proposed to detect each compartment's pressure variation or pressure drop. This test is a more confidential compartment leak test than the current method, and the test device can show real-time pressure detection values of each of the pressure sensors, which are installed in each compartment, including unmanned space.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.5
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• pp.577-585
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• 2015

This paper deals with development of an autopilot system for leisure yacht based on NMEA 2000 network and android platform. The developed system can operate both for manual steering and automatic navigation mode. In automatic steering mode, after manipulation of commands which are NMEA 0183 sentences by android platform, the developed system translates and sends the packets through NMEA 2000 network. Then the controller which is connected to NMEA 2000 network receives the commands and controls the boat's rudder system automatically. The automatic steering mode is achieved by cooperation of two controllers; one for controlling the rudder system, and the other for controlling the vessel's heading. To control the vessel's rudder and heading angle two PID controllers are developed with an adjustable dead-band gain. Also, in order to eliminate the steady-state error occurred by applying dead-band, an integral controller which specifically supervises the system's behavior inside the dead-band area is developed. In this paper, at the first stage, simulations are accomplished using computer in order to examine the feasibility of the proposed based on simulation results. In the next step, the system on a real hydraulic steering model is implemented and at the end the performance examination by implementing it on a real boat and doing test navigation is executed.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.159.2-159.2
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• 2011

Hyundai Heavy Industries has developed a tidal current energy converter utilizing the accumulated technology as the world largest constructor for ship and offshore structures. The model has two sets of turbines in both ends in order to utilize the bi-directional current flows in flood and ebb tide. The torque produced by turbine in tidal current is directly delivered to generator along the horizontal axis, in which the turbine, gear, generator, gear and turbine are connected successively. The manufactured model for field test has the turbine diameter of 5 meters to produce the maximum power of 500kW at maximum current speed of 5m/s. The technical verification of tidal power converter was performed by means of small scale model test in towing tank as well as field test at the Strait of Uldolmok located in Jindo of Jeollanamdo province. Field test was performed by mounting the tidal current converter on the SEP(Self Elevating Platform) which could lower the 4 vertical legs on the seabed and could elevate platform over the water surface using the hydraulic power for itself. The field test performed for a month shows that power output is similar or larger compared with the expected one in design stage. This paper presents the development of tidal current energy converter and real sea field test by Hyundai Heavy Industries. This project has finished successfully and provided the technical advance toward commercial services for tidal current power generation in the south-west region in Korea.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.5
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• pp.451-456
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• 2011

To ensure structural integrity of membrane type LNG tank, the rational assessment of the sloshing impact responses of tank structures should be preceded. The sloshing impact pressures acting on the insulation system of LNG tank are typical irregular loads and the resulting structural responses show very complex behaviors accompanied with fluid structure interaction. So it is not easy to estimate them accurately and immense time consuming calculation process would be necessary. In this research, a simplified method to analyse the dynamic structural responses of LNG tank insulation system under pressure time histories obtained by sloshing model test or numerical analysis was studied. The proposed technique based on the concept of linear combination of the triangular response functions which are the transient responses of structures under the unit triangular impact pressure acting on structures. The validity of suggested method was verified through the example calculations and applied to the dynamic structural response analysis of a real Mark III membrane type insulation system using the sloshing impact pressure time histories obtained by model test.

• Journal of Advanced Navigation Technology
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• v.15 no.1
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• pp.25-31
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• 2011

Recently NMEA 2000 protocol is familiarized as a standard real time instrument network of SOLAS ship. This paper is studied to develop NMEA 2000 based two-dimensional ultrasonic anemometer which is core device for navigation as a sensor of wind speed and direction using ultrasonic including temperature and barometer. Developed system is connected to NMEA 2000 network which is composed of various kinds of merchandised NMEA 2000 device such as depth gauge, speed gauge, GPS device etc. to test connectivity with other NMEA 2000 device and functional test are carried out as weather station in comparison with other merchandised weather station which are developed advanced foreign company to ascertain usability as a weather station on board.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.9
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• pp.1788-1795
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• 2017

In this paper, we proposed a service that provides CPA/TCPA information to ships, without ARPA/ATA devices to support decision making of the navigator for maritime safety based on various services at shore and off-shore. To verify the proposed service, we use SiNAS (scenario-based simulator for NAS) with CPA/TCPA information providing software to evaluate its usability, because executing the test in real ship has many limitations and difficulties. To do this, we specify two simulation scenarios for the required purpose, and we liaise twelve participants with various navigation experience to conduct the simulations. Also, we analyze the results of simulation using mission success or not, the minimum approaching distance with the target ship, the time of a recognition the target ship, the time of a first action for collision avoidance with the target ship, and so on. Then, we evaluate usability of the proposed service based on the three elements which are effectiveness, efficiency and satisfaction.