• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.725-731
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• 2003

Reduction of a ship's rolling is the most important performance requirement for improving the safety of the crew on board and preventing damage to cargos as well as improving the comfort of the ride. A mass driving anti-.oiling system (MD-ARS) might be one candidate of several systems against the ship's rolling. As the movable range of the mass on the ship is finite, the control system must include restriction on the mass position to protect the device and the ship. This restriction usually causes windup phenomenon and control performance is deteriorated seriously. We adopt anti-windup technique to improve the control performance and demonstrate its efficiency by simulation.

• 한국산업융합학회 논문집
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• 제24권5호
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• pp.625-633
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• 2021

This paper considers the development of safety operation guideline for onboard A-Frame system used to operate heavy-work ROV using dynamic simulation. Onboard A-Frame is affected by ship's behavior and large inertia by the marine environment. For this reason, safety operation guidelines are required for the safety of workers who operate ship-mounted equipment. In order to develop a guideline, it is necessary to evaluate the safety loads through real sea experiment. However, simulation method is used instead since it is difficult to conduct experiments in sea. Therefore, a procedure for safety operation analysis based on dynamic simulation that can consider ship behavior and marine environment and a safety operation table were proposed in this study. And the construction of safety operation table and guide for safety operation using the applied load and safety factor analysis results were considered.

• 한국산업융합학회 논문집
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• 제25권5호
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• pp.799-810
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• 2022

Welding work is a production work method widely used throughout the industry, and various types of welding technologies exist. In addition, many methods are being studied to automate these welding operations using robots, but in the ship manufacturing field, welding such as painting, cutting, and grinding is also the most common operation, but the manual operation ratio is higher than in other industries. Such a high manual labor ratio in the field of ship manufacturing not only causes quality problems and production delays according to the skill of workers, but also causes problems in the supply and demand of manpower. Therefore, this paper analyzed the reason why the automation rate is low in welding work at ship manufacturing sites compared to other industries, and analyzed the production process and field environment for small and medium-sized ship manufacturing companies that repeatedly manufactured with a small quantity production method. Based on the analysis results, it is intended to propose a robot system that can easily move between workplaces and secure uniform welding quality and productivity by collaborating simple welding tasks with humans. Finally, the simulation environment is constructed and analyzed to secure the suitability of robot system application to current production site environment, work process, and productivity, rather than to develop and apply the proposed robot system. Through such pre-simulation and robot system suitability analysis, it is expected to reduce trial and error that may occur in actual field installation and operation, and to improve the possibility of robot application and positive perception of robot system at ship manufacturing sites.

• 대한조선학회논문집
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• 제47권2호
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• pp.188-195
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• 2010

Green water load is an important parameter to be considered in designing a modern ship or offshore structures like FPSO and FSRU. In this research, a numerical simulation method for green water phenomenon is introduced. The Navier-Stokes equations and the continuity equation are used as governing equations. The equations are calculated using Finite Difference Method(FDM) in rectangular staggered grid system. To increase the numerical accuracy near the body, the Cartesian cut cell method is employed. The nonlinear free-surface during green water incident is defined by Marker-density method. The green waters on a box in regular waves are simulated. The simulation results are compared with other experimental and computational results for verification. To check the applicability to moving ship, the green water of the ship which is towed by uniform force in regular wave, is simulated. The ship is set free to heave and to surge.

• 해양환경안전학회지
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• 제3권S1호
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• pp.55-73
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• 1997

It is well known that simulation study in the preliminary design stage of harbors or berths is of great use, since it can provide helpful informations to the designer from the view point of ship navigations. In this paper, a brief review is made in the safety assessment of ship navigation for a 320,000 DWT VLCC entering Yecocheon harbor area, which is carried out by shiphandling simulator system. The geographic data base for the harbor as well as the mathematical models of the ship and environmental effects are designed and developed. Based in the on-site inspections and interviews with pilots in Yeocheon area, basic maneuvering plans and consistence with real operation conditions. Berthing and deberthing maneuvering simulations as well as approaching and departing simulations are carried out by 3 experienced navigators according to the maneuvering plans and environmental scenarios. The simulation results are analysed in various ways to evaluate the quantitative and qualitative maneuvering difficulties and thereby to assess the safety of ship navigation in that area.

• 대한조선학회논문집
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• 제40권2호
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• pp.41-48
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• 2003

The human behavior is very important in development of simulation system for evacuation analysis. The walking speed of passenger is especially affected by dynamic effect and list due to damage and ship motion in wave. There are various methods to get an useful data for evacuation simulation. The onboard experimental approach is one of the most strong method. In this paper, the onboard experiment is performed to obtain human behavioral data. To realize ship trim and heel due to maritime casuality, the passage model for experiment is made. The experiment is carried out at dynamic and static condition respectively using the ship with passage model. The result is evaluated and it will be reflected in evacuation simulation tool.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.47-52
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• 2006

Recent warnings indicate that there is a potential risk of massive earthquake in Japan within 30 years. These earthquakes could produce large-scale tsunamis. Tsunamis are very powerful and can be traveled thousands of miles and caused damage in many countries. Consideration of the effect of tsunami to the moored ship is very important because it brings the loss of life and vast property damage. In this paper, the numerical simulation procedure to analyze the motions of a moored ship due to the observed waves of tsunami, Tokachi-off earthquake tsunami profile in northern Pacific coasts of Japan on September 26 in 2003. And the effects on the motions and mooring loads are investigated by numerical simulation. Numerical simulations consist of hydrodynamic analyses in a frequency domain and ship motion analyses in a time domain as the motions of moored ships are examined. As the process begins, the hydrodynamic and waveexciting forces for moored ships must be calculated. Ship motions and mooring forces can then be calculated by solving the equations of motion. In order to investigate the safety evaluation on the motions of moored ship by tsunami attack, we applied a numerical simulation procedure to a 135,000m3 LNG carrier moored at an offshore sea berth.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.209-211
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• 2006

Auto Steering System is the device for course keeping or course altering to ship's steering system. The purpose of automatic steering system is to keep the ship's course stable with the minimum course and rudder angle. Recently, modern control theories are being used widely in analyzing and designing the ship system. Though P.D type auto pilots are widely used in ships, the stability and the adjusting methods are not clarified. In this paper the authors proposed auto steering system with Hybrid Controller. The things that the actual operators of a steering wheel has acquired through their experience can be logically described by the Lingustic Control Rule. The characteristic of the control system were investigated through the computer simulation results. it was found that the Hybrid control was more efficient than the PD control system.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.943-956
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• 2020

In this study, the motion control problem of the vessel towed by a towing ship (tugboat) is considered. The non-powered towed ship is dragged by the towing ship. Even though the towed ship is equipped with propulsion systems, they cannot be used at low or constant speeds due to safety issues. In narrow canals, rivers, and busy harbor areas especially, where extreme tension is required during towing operation, the course stability of the towed vessel depends on the towing ship. Therefore, the authors propose a new control strategy in which the rudder system of the towed vessel is activated to provide its maneuverability. Based on the leader-follower system configuration, a nonlinear mathematical model is derived and a back-stepping control is designed. By simulation and experiment results with a comparison study, the usefulness and effectiveness of the proposed strategy are validated.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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• pp.251-256
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• 2005

There is few study which automatically diagnose the fault from ship's monitored signal. The bigger control and monitoring system is, the more important fault diagnosis and maintenance is to reduce damage brought forth by system fault. This paper proposes fault diagnosis system using a correlation analysis algorithm which is able to diagnose and forecast the fault and is composed to fault detection knowledge base and fault diagnosis knowledge base. For this all kinds of ship's engine room monitored data are classified with combustion subsystem, heat exchange subsystem and electric motor and pump subsystem by analyzing ship's operation data. To verifying capability of fault detection, diagnosis and prediction, Fault Management System(FMS) is developed by C++. Simulation experiment by FMS is carried out with population data set made by log book data of 2 months duration from a large full container ship of H shipping company.