• 수산해양교육연구
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• 제29권2호
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• pp.415-421
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• 2017

This study is aiming to find one of working conditions for loading and unloading a large ship at game port. Firstly, for dynamic analysis of the moored ships, the motion characteristics of ship according to loading condition are figured out. The motion characteristics of ship is related to environmental factors such as current, wind, mooring line, fender and etc. As a result, it is ascertained through numerical simulation using the AQUA MARINE developed by ANSYS INC. This study might contribute to make a new method of mooring stability of target ship.

• Journal of Advanced Marine Engineering and Technology
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• 제39권5호
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• pp.554-562
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• 2015

This paper describes an analysis of an architecture and control system of a firefighting cannon manipulator (FCM) composed of two joint axes and one water-shooting actuator. Because the orienting FCM motion is disturbed by the reaction force from water shooting, the water shooting force has been modeled for robust control. The dynamics model of the manipulator has been set up including the external force of water-shooting reaction on the manipulator. A PD Controller and Sliding Mode Controller have been designed and their performance been tested through simulation to track a desired trajectory under the disturbance of a water-shooting reaction. The simulation shows that the performance of the Sliding Mode Controller is better than that of the PD controller.

• Journal of Advanced Marine Engineering and Technology
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• 제26권5호
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• pp.581-588
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• 2002

A fuzzy learning control algorithm is proposed in this paper. In this method, two fuzzy controllers are used as a feedback and a feedforward type. The fuzzy feedback controller can be designed using simple knowledge for the controlled system. On the other hand, the fuzzy feedforward controller has a self-organizing mechanism and therefore, it does not need any knowledge in advance. The effectiveness of the proposed algorithm is demonstrated by experiment on the position and force control problem of a parallelogram type robot manipulator with two degrees of freedom. It is shown that the rapid learning and the robustness can be achieved by adopting the proposed method.

• Journal of Advanced Marine Engineering and Technology
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• 제31권4호
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• pp.350-355
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• 2007

Pad-eye is connected to crane with sling. When block is lift, pad-eye have a various applied force. Applied force on pad-eye is related to sling angle. Sling angle is decided by various parameters, including pad-eye location, sling length and crane location. Welded joint on pad-eye requires strength design because sling angle changes force on pad-eye. Strength design for welded joint of pad-eye will calculate with general mechanical design and FE analysis. FE analysis would become a useful tool in the analysis of welded joint. A commercial software(ANSYS 10.0) was used in the structural strength analysis for welded joint of pad-eye.

• 한국해양공학회지
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• 제19권1호
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• pp.77-86
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• 2005

Over the last 10 years, significant changes have taken place in the world of container shipping. The size and the speed of the quay-side crane have been increased considerably. As a result, the stiffness of a crane is decreased and the sway oscillation of cargo may become violent. The purpose of this paper is to determine the design force caused by the sway oscillation of the cargo, lifted by four ropes, with an initial fleet angle, and the governing equations of the lifting system for an anti-sway control system design.

• 대한조선학회지
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• 제13권2호
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• pp.13-43
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• 1976

A potential flow approach is used to develop a method and an associated computer program for floating marine structures of general configuration in wave of all water depths with arbitrary heading. It computes the total force distributions and six degrees-of-freedom motion. The hydrodynamic-force equations and derived become identical under certain assumptions to the equations commonly used by the offshore industry, and the two methods are compared in detail. The computed motions of all six degree agree quite well with model-scale and full-scale experimental data for two typical semisubmersible drilling rigs in finite-depth water. Also the presented motion computations are more accurate than a previous work by the second approach. The present computations use experimentally validated or determined values of frequency-dependent hydrodynamic coefficients with the effects of the free surface and both finite and infinite water depths. The present method generates sufficient computation accuracy to use for practical design applications.

• 해양환경안전학회지
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• 제15권2호
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• pp.105-110
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• 2009

국내에서는 해양오염을 예방하기 위하여 해양오염방지관리인 제도를 운영하고 있다. 2007년 1월 19일 해양환경관리법(법률 제8260호)이 제정되어 2008년 1월 20일부터 시행으로 됨으로써 1977년 제정되어 시행되어 오던 해양오염방지법이 폐지됨에 따라 해양오염방지관리인 교육 제도에도 변화가 생겼다. 주요 개정 내용은 교육훈련기관, 교육훈련과정, 교육훈련대상자, 해양오염방지관리인 업무내용 및 준수사항, 해앙시설의 범위, 교육과목 등이다.

• 해양환경안전학회지
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• 제21권6호
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• pp.744-750
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• 2015

본 연구에서는 해상에서 선박의 외측 표면 검사를 위한 모바일 로봇의 개발에 대해 언급하였다. 해상에서 선체 측면에 대한 검사를 육안으로 진행하기 어려우며 이러한 검사를 효과적으로 수행하기 위해 모바일 로봇은 선체 측면에 부착되어 주행할 수 있는 기능을 갖추어야 한다. 이를 위해 선체 측면과의 부착력을 발생시키기 위해 영구 자석 모듈을 도입하였고, 곡면 주행 시 자기력의 변화를 최소화하는 구조로 설계를 하였다. 이러한 설계를 바탕으로 4개의 네오디움 자석, 4개의 구동바퀴, 영상 획득 모듈로 구성되는 모바일 로봇을 제작하였다. 제작된 로봇에 대해 선체와의 부착력을 확인하기 위한 하중 실험을 실시하였고, 주행이후 정지 시 측면 미끄럼 실험과 주행 속도 측정 실험을 실시하였다. 실험 결과 13 [Kgf]까지 선체와의 부착력을 유지할 수 있었고, 미끄러짐이 없는 하중은 8 [Kgf]까지였다. 주행 실험에서는 6.5 [A]의 전류에 대해 0.82 [m/s]의 속도로 주행할 수 있는 것을 확인하였다. 선박의 표면 검사를 위해 개발한 모바일 로봇의 특성 실험을 통해 로봇의 유용성을 확인할 수 있었다.

• 대한조선학회 특별논문집
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• 대한조선학회 2005년도 특별논문집
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• pp.206-210
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• 2005

As design trends has changed to have flexible aft hull structure, increased power output and stiffer shafting system, owners and classification societies have more concerned about shaft alignment. In the shaft alignment analysis, there are many uncertainties which are related in propeller generated force, bearing stiffness, crank shaft model and etc. in this study, it is focused on the effect of crankshaft model by comparing between equivalent model and actual crankshaft model.

• 한국초전도ㆍ저온공학회논문지
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• 제23권3호
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• pp.10-13
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• 2021

The method of removing micro-plastics from sea water has been developed using electro-magnetic force. Plastics are difficult to decompose and put a great load on the marine environment. Especially a plastic with a size of 5 mm or less is defined as micro-plastic and are carried by ocean currents over long distances, causing global pollution. These are not easily decomposed in the natural environment. The Lorentz force was generated in simulated sea water and its reaction force was applied to the micro-plastic to control their motion. Lorentz force was generated downward and the reaction force to the plastics was upward. The plastic used in the experiment was polystyrene with a diameter of 6 mm, and the density was 1.07 g/cm³. The polystyrene sphere levitated at the current density of 0.83 A/cm² and the external field of 0.87T. The particle trajectory calculation was also made to design separation system using superconducting magnet.