• Korean Journal of Computational Design and Engineering
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• v.16 no.3
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• pp.227-235
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• 2011

Ship handling simulator should have capabilities of calculating ship motions (heave, pitch, and roll) at given sea state and displaying the calculated motions through a real-time 3D visualization system. Motion solver of a ship handling simulator generally calculates those motions in addition to position for an own ship, a main simulation target, but provides only position information for traffic ships. Therefore, it is required to simulate real-time traffic ship and buoy motions coupled with ocean waves in a ship handling simulator for the realistic visualization. In the paper, the authors propose a simple dynamics model by which ship and buoy motions are calculated with the input data of wave height and discuss a method for the implementation of a ship and buoy motions calculation module.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.1
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• pp.86-93
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• 2015

Recently, the development of Maritime Service Portfolios (MSPs) for the safe navigation of ship has been discussed internationally. For the successful service of the MSPs, first of all, studies for the standardization about the structure and data structure of MSPs should be preceded. Also, it is necessary to evaluate and assess whether the services are effective for safe navigation, and provided data and portrayal methods are proper. However, because great dangers will be accompanied when untested MSPs about their effectiveness and safety are applied in real ship navigation, it is necessary that effectiveness and safety of the MSPs should be proven under various navigational conditions and environments by simulation. In this paper, we propose a 3D navigation simulation system using desktop PC environment, which is proper for evaluating the effectiveness of MSPs. The system consists of three modules which are simulation scenario editor, 3D visualization of navigational environment and 2D navigational equipment. The scenario editor module provides an environment setting for simulation, such as properties, routes and positions of vessels and aids to navigations. It also provides functions to create a scenario for the simulation to operate. Additionally, the 3D visualization module provides 3D navigational environment which shows interplay between geographical and navigational environment based on the created scenario. The 2D navigational equipment module provides visualization functions of various navigational equipment, shows the interaction between ship's navigational equipment and ship's environment. The simulation scenario, in which various kinds of ships are routing in the port, is created by the developed simulation system, and experimented whether this developed system is appropriate to evaluate and assess the MSPs developed by the International Maritime Organization.

• Journal of Ocean Engineering and Technology
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• v.13 no.4 s.35
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• pp.118-123
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• 1999

The mathematical model used in the simulation of ship's maneuvering contains the hydrodynamic coefficients, which are usually evaluated based on PMM model tests in the towing tank and used to predict ship's maneuvering performance when applied to the proto-type ship. The proper mathematical model has to be developed to predict ship's maneuvering motions with hydrodynamic coefficients very well. The mathematical model for PMM model tests is analyzed with identification program and the hydrodynamic coefficients and maneuvering motions by system identification we compared with those obtained directly from PMM model tests and sea trial. The mathematical model for PMM model tests was established and the magnitudes of ship's maneuvering coefficients were determined. When the identified values of coefficients were used to simulate the maneuvers, a very good agreement was obtained between the numerically simulated motion responses and those obtained from PMM model tests.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.9
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• pp.33-42
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• 1998

If a ship diesel engine is operated by consolidated control with Controllable Pitch Propeller(CPP), the minimum fuel consumption is achieved together with the demanded ship speed. For this, it is necessary that the ship is operated on the ideal operating line which satisfies the minimum fuel consumption and that the pitch angle of CPP and throtle valve angle are controlled simultaneously. In this point of view, this paper presents a controller design method for a ship propulsion system with CPP based on the decoupling control theory. To do this, Linear Matrix Inequality(LMI) approach is introduced for the control system to satisfy the given $H_\infty$ control performance and robust stability in the presence of physical parameter perturbations. The validity and applicability of this approach are illustrated by simulation in the all operating ranges.

• Journal of the Korea Society for Simulation
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• v.19 no.4
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• pp.31-41
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• 2010

So far, many simulation researches associated with naval ships have been concentrated on the tactical systems and naval ship development. However, studies on the improvement of living conditions for naval ship crews were limited. This study targets a crew mess room which is a typical welfare facility in naval ships and existing modeling and simulation methodologies for naval tactical and strategic systems cannot be applied to the crew room simulations. This paper suggests a simulation modeling framework based on 3-dimensional discrete event simulation methodology for crew mess room congestion assessment and operation scenarios. The simulation modeling framework is verified through practical case simulations. The purpose of simulation modeling framework consists of process and system architecture for operation feasibility tests of welfare facilities in naval ships and is to guide an assessment of the operability performance of a crew mess room.

• Journal of Navigation and Port Research
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• v.38 no.6
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• pp.689-694
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• 2014

The Korean government has introduced and enforced maritime traffic safety assessment to secure traffic safety since 2010. The maritime traffic safety assessment is needed by law to design a new port or modify an existing one. According to Korea Maritime Safety Act, in the assessment the propriety of marine traffic system consists of the safety of channel transit and berthing/unberthing maneuver, safety of mooring, and safety of marine traffic flow. The safety of channel transit and berthing/unberthing maneuver can be evaluated only by ship-handling simulation. The ship-handling simulation is carried out by sea pilots working with the port concerned. The vessel's proximity measure is an important factor to evaluate traffic safety. The proximity measure is composed of vessel's closest distance to channel boundary and probability of grounding/collision. What is more, the probability of grounding becomes important. According to central limit theorem, a sample has a normal distribution on condition that its size is more than 30. However, more than 30 simulation runs bring about the increase of assessment period and difficulty of employing sea pilots. Therefore this paper is to find out minimum sample size for evaluating vessel's proximity. First sample sets of size of 3, 5, 7, 9 etc. are selected randomly on the basis of normal distribution. And then KS test for goodness of fit and t-test for confidence interval are applied to each sample set. Finally this paper decides the minimum sample size. As a result this paper suggests the minimum sample size of 5, that is, the simulation of more than five times.

• Journal of Navigation and Port Research
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• v.32 no.3
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• pp.207-213
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• 2008

Ship-handling simulation system has been used for maritime traffic safety assessment for harbor and fairway. There exist various environmental conditions under which ship may navigate along a fairway or in harbor. Due to the time and budget limitations, however, ship-handling simulations are usually carried out for very limited number of environmental conditions. In this paper, statistical method for effective and systematic determination of real time simulation conditions is suggested and applied to the maritime traffic safety assessment problems. In the empirical study, the principal component analysis method and the concept of empirical cumulative distribution function are suggested to estimate synthetic navigational difficulty and to select simulation conditions which would impose high difficulty on shiphandling.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.5
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• pp.507-512
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• 2007

This paper presents a tracking filter with ship's motion compensation for a ship-borne radar tracking system. The ship's maneuver is described by displacement and rotational motions in the ship-centered east-north frame. The first order Taylor series approximation of the measurement error covariance of the converted measurement is derived in the ship-centered east-north frame. The ship's maneuver is compensated by incorporating the measurement error covariance of the converted measurement and displacement of the position state in the tracking filter. The simulation results via 500 Monte-Carlo runs show that the proposed method follows the target successfully and provides consistent tracking performance during ship's maneuvers while the conventional tracking filter without ship motion compensation fails to track during such periods.

• Special Issue of the Society of Naval Architects of Korea
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• 2011.09a
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• pp.75-81
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• 2011

An indirect concept and method is proposed to predict the paint dry time at the inside wall of ship block. To implement this concept on computer program, optimal hot air supply-exhaust system of paint dry facility was designed by CFD simulation and experiment was performed to get the paint dry time curve according to various paint dry conditions. After combining the block inside environment from the simulation results and the paint dry time prediction curve from the curve-fitting of experimental result, the GUI program which can be executed in general PC OS has been finally developed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.11
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• pp.1612-1618
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• 2021

The telegraph controller is a device used to control the speed of a ship, and it is a device that has a very direct effect on the safety of the crew. Accordingly, ship owners demand very high reliability of the telegraph controller, and the classification trend is to introduce HILS (hardware in loop system) test as a method to verify reliability. Therefore, in this paper, an electric propulsion ship was modeled to perform the HILS test of the Telegraph controller. For modeling, the specifications of the electric propulsion tug boat were defined, and the battery parts, propulsion motor parts, and ship model parts were modeled. In addition, various operation scenarios were defined and the Telegraph controller was modeled accordingly. Finally, the results of the integrated model were confirmed through simulation.