• Journal of Advanced Marine Engineering and Technology
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• v.34 no.1
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• pp.125-132
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• 2010

IEC61162-3 known as NMEA2000 protocol is approved as a standard network of SOLAS ship by ISO and used for the instrument network which exchanges data in real-time. For easy the development of ship network equipments, this study is focused on the development of SoC which can convert to NMEA2000 protocol from various kind of protocols such as TCP/IP, NMEA0183, RS422 and others using FPGA and u-Blaze. In this paper, we composed NMEA2000 protocol stack on FPGA and verified NMEA2000 network communication of FPGA system by connecting with commercialized devices through PC Hyper-terminal and network monitoring program.

• Journal of Advanced Research in Ocean Engineering
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• v.3 no.3
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• pp.149-157
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• 2017

Since sloshing effects influences ship motions including floater's natural frequencies. The significant factors changing ship motions are inner liquid impact loads and inertia forces and moments with respect to its filling ratio. This means that changing sloshing loads with sloshing effects reduction device (SERD) may control ship motions. In this regard, conceptual model for adjustable SERD was suggested by authors and then implanted into fully coupled program between vessel motion and sloshing. By changing clearances of baffles in the inner tank which were component of SERD, then the roll RAOs from each case were obtained. It is revealed that using well-controlled SERD can maintain natural frequencies of floater even inner tank has different filling ratio.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2004.04a
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• pp.144-148
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• 2004

Recently, various studies had been made for automatic control system of small ships, in order to improve maneuvering and to reduce labor and working on board. To achieve efficient operation of small ships, it had accomplished to rapid development of automatic technique, but the ship operation had been more complicated because of the need to handle various gauges and instruments. To solve these problems, there are examples to be applied to the speech information processing technologies which is one of the human interface methods in the system operation of ship, but the implementation of definite system is still incomplete. Therefore, the purpose of this paper is to implement the control system for ship steering using the voice recognition module.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.121.3-121
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• 2001

The movement of a ship is important for DBS(Direct Broadcasting Satellite) Receiving Antenna control algorithm design on shipboard. Especially, turning of ship is essential factor to affect the angle change of azimuth and elevation. Therefore, to track the satellite stably, we need the tracking method considering turning rate of ship. In this paper, we propose an effective satellite tracking algorithm for DBS receiving antenna on shipboard. In the proposed method, when a ship is turned, it selects one of the Multi tracking modes - Normal mode, Low speed mode, Middle speed mode and High speed mode - according as turning rate to be calculated by using Gyro sensor.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.4
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• pp.553-561
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• 2009

This paper presents development of ROV-type underwater robot capable of cleaning ship hull in automatic mode. The purpose of developing this robot is for underwater cleaning to secure the safety of divers who inspect and clean the ship hull. The robot consists of the cleaning system with rotating brush mechanism, a car-like driving mechanism, inspection system using video, and overall control system for underwater communication and operation. In this paper, we present overall design process of the cleaning system and operating system and technical contents of the overall control system for the underwater cleaning robot.

• Journal of the Korean Institute of Navigation
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• v.22 no.4
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• pp.45-50
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• 1998

A recently constructed commercial ship is a complexive integrated system like a small city in which has a generator, power distributing facilities, various radio equipments and high power circuit breakers are installed. Therfore it could make a malfunction of the microprocessor in the various control units which are so important during the ocean voyage of larger ship. This paper has studied whether is properly required or not on the view of the actual electro magnetic compatibility status on the electromagnetic interference and suceptibility test requirments listed on the IACS (International Association of the Classification Society). Through these results, we are looking forward to the new suggestions of the Electro Magnetic Compatibility test in order to reduce the malfunction in the ship regarding test item, test level, and test condition.

• Journal of the Society of Naval Architects of Korea
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• v.45 no.3
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• pp.247-257
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• 2008

In this paper, a free running system, which is developed recently for a 2m-class ship models, will be introduced. For the remote control of hardware, GUI of software packages was developed using Visual Basic 6.0, and Host PC with Positioning Board manages Servo drive. Then the drive operates propeller and rudder. Its control performance will be shown. Also its adaptability to the resistance, manoeuverability and seakeeping model tests will be considered through the installation on a KTTC standard ship model from MOERI.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.2
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• pp.178-184
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• 2002

This paper deals with the transfer alignment problem of SDINS(StrapDown Inertial Navigation System) subjected to roll and pitch motions of the ship. In order to reduce alignment errors induced by ship body flexure, a linearized error model for the velocity and attitude matching transfer alignment system is first derived by linearizing the nonlinear measurement equation with respect to the dominant y axis component and defining the flexure state of random constant type. And then a robust state estimation scheme is introduced to account for modeling uncertainty of the flexure. By interpreting the simulation results and comparing with the velocity and DCM(Direction Cosine Matrix) partial matching method, it is shown that the proposed method is effective enough to improve the azimuth alignment performance.

• Journal of the Korean Institute of Navigation
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• v.4 no.1
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• pp.19-30
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• 1980

The usual procedure for the optimal design of ship's steering system is to minimize a chosen quadratic performance index, which isdetermined from the view point of economic run. However, the optimal control synthesized in such a straightforward fashion is unsatisfactory because ship's parameters differ from their nominal values due to uncertainties and errors in measurement and/or simplifications in mathematical modelling, and/or the variation of the ship's loading condition. In an attempt to resolve this difficulty, this paper presents a method for designing a low sensitive optimal steering system in a way as to minimize not only given performance index but also the sensitivity of the performance index and trajectory sensitivity. It is also shown that the optimal control so obtained will result in a system whose performance index and transient response are low sensitive to small varation in ship's time constant.

• Journal of Ocean Engineering and Technology
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• v.37 no.3
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• pp.122-128
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• 2023

Autonomous berthing is a crucial technology for autonomous ships, requiring optimal trajectory planning to prevent collisions and minimize time and control efforts. This paper presents a two-phase, two-point boundary value problem (TPBVP) strategy for creating an optimal berthing trajectory for a twin-propeller, twin-rudder ship with autonomous berthing capabilities. The process is divided into two phases: the approach and the terminal. Tunnel thruster use is limited during the approach but fully employed during the terminal phase. This strategy permits concurrent optimization of the total trajectory duration, individual phase trajectories, and phase transition time. The efficacy of the proposed method is validated through two simulations. The first explores a scenario with phase transition, and the second generates a trajectory relying solely on the approach phase. The results affirm our algorithm's effectiveness in deciding transition necessity, identifying optimal transition timing, and optimizing the trajectory accordingly. The proposed two-phase TPBVP approach holds significant implications for advancements in autonomous ship navigation, enhancing safety and efficiency in berthing operations.