• Journal of Advanced Research in Ocean Engineering
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• v.3 no.4
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• pp.193-203
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• 2017

This study investigated the steady-flow effects present in the numerical computation of the resistance added to a ship in waves. For a ship advancing in the forward direction, a time-domain 3D Rankine panel method is applied to solve the ship motion problem, and the added resistance due to waves is calculated using a near-field method, with the direct integration of the second-order pressure on the hull surface. In the linear potential theory, the steady flow is approximated by the basis potential of a uniform flow or double-body flow in order to linearize the boundary conditions. By applying these two different linearization schemes, the coupling effects between steady and unsteady solutions were examined. Furthermore, in order to analyze the steady-flow effects on the hull geometry, the computation results for two realistic hull forms, a KVLCC2 tanker and DTC containership, were compared. In particular, the mj term, which represents the coupling effects under the body boundary condition, was evaluated considering the geometry of a non-wall-sided ship. Lastly, the characteristics of the linearization schemes were examined in relation to the disturbed waves around a ship and the components of added resistance.

• Journal of Advanced Research in Ocean Engineering
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• v.3 no.2
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• pp.83-101
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• 2017

In this study, the added resistances of the large container ship in head and oblique seas are evaluated using a time-domain Rankine panel method. The mean forces and moments are computed by the near-field method, namely, the integration of the second-order pressure directly on the ship surface. Furthermore, a weakly nonlinear approach in which the nonlinear restoring and Froude-Krylov forces on the exact wetted surface of a ship are included in order to examine the effects of amplitudes of waves on ship motions and added resistances. The computation results for various advance speeds and heading angles are validated by comparing with the experimental data, and the validation shows reasonable consistency. Nevertheless, there exist discrepancies between the numerical and experimental results, especially for a shorter wave length, a higher advance speed, and stern quartering seas. Therefore, the accuracies of the linear and weakly nonlinear methods in the evaluation of the mean drift forces and moments are also discussed considering the characteristics of the hull such as the small incline angle of the non-wall-sided stern and the fine geometry around the high-nose bulbous bow.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.9
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• pp.1965-1971
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• 2010

A ship propulsion thruster platform which is used by safety sailing takes charge of remote control of a main engine in ship. This system not only guarantees safety and reliable flight sailing but also require remote control technology of a ship. Accordingly, in this paper it deals with a telegraph lever control unit system which is a part of propulsion thruster system as localization technology. Also it makes sure of knowledge and core technology through analysis and designing and developing a telegraph lever control unit system. Moreover, it is sure of acquisition of base technology for integration of a ship propulsion thruster platform.

• Journal of the Society of Naval Architects of Korea
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• v.49 no.2
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• pp.109-115
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• 2012

Slamming phenomenon may occur when a ship navigates a high sea region, where the response of ship can be expected as elastic behaviour and the resultant wave loads may increase. In this paper, numerical analysis of ship motions and wave loads including momentum slamming was performed using the strip theory with regular waves. In order to analyze the effect of slamming force on the global ship motions, time histories of each mode of displacement and forces were simulated by using Newmark-beta time integration scheme. The added mass and damping coefficients calculated by Lewis form method were compared with the results of given references. For verification of numerical results, the motion RAOs of a S175 containership were calculated as an example of application and time histories of respective displacement and vertical bending moment were compared with the results of ITTC workshop benchmark test.

• Korean Journal of Computational Design and Engineering
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• v.16 no.3
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• pp.187-196
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• 2011

Generally, BOM (Bill of Material) means a part list which is needed to manufacture or assemble a product or part. During manufacturing processes, BOM is inevitably required for most of enterprise processes such as design, procurement, production planning/control, resource planning, and financial works. Every manufacturing industry uses many kinds of BOM's that are adjusted to the requirement of functions of their work division. Moreover, BOM evolves in different forms according to the product development phases such as conceptual design; function design, detail design, and production design because it is necessary to use different product structures to keep product data generated throughout the lifecycle of a product. This includes all data and information related to the all the product development phases. Shipbuilding works also are processed and controlled based on BOM. However, effective maintenance of ship outfitting BOM data is getting difficult as the amount and complexity of data have increased due to variety and long lifecycle of ship. For the effective management of outfitting BOM data, two aspects must be considered. One is how to classify numerous BOMs type and the others how to display BOMs. So this study suggests a method to classify BOM types and propose two categories - Structure BOM, Display BOM. Base on this result, we propose the integrated ship outfitting BOMs model and analysis outfitting BOMs.

• Journal of the Society of Naval Architects of Korea
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• v.54 no.2
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• pp.83-89
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• 2017

Numerical simulations of ship resistance have been performed to compare spatial characteristics of Courant number when using structured and unstructured meshes. When Euler scheme was used for time integration, the structured mesh provided a more efficient calculation because the calculation time interval was larger than that of unstructured mesh. The automatic generation of very small meshes in the unstructured mesh was mainly responsible for the limitation of calculation time interval. When local time stepping Euler scheme was applied, however, the ship resistance of unstructured mesh showed a rapid convergence while a slow convergence of ship resistance in structured mesh was caused by the small time interval in bulbous bow.

• IE interfaces
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• v.13 no.1
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• pp.65-77
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• 2000

Nowadays, the modeling of systems have been enabled by various models and methodologies that are used for different purpose and perspectives upon the systems. The integrated modeling methodology that integrates these models and methodologies has become challenging issues in system integration such as CIM and PDM. The primary objective of this paper is to propose the comprehensive integrated modeling methodology that integrates the Extended IDEF0 function model, OOIDEF0 information model, navigation model, interface model, and organization model for an effective analysis and design of the CIMS for ship production. This methodology can be used for the integrated system, and cover the systems development life cycle in an integrated fashion. In order to prove the consistency and efficiency of the proposed methodology, the CIMS for ship production is modeled.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.4 s.142
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• pp.379-387
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• 2005

A ship may suffer sinkage and heel due to flood in a compartment caused by damage on a deck. The motion and waveloads of the heeled ship floating in waves have been analyzed by making use of a three dimensional potential theory taking account of the hydrodynamic pressure in the flooded compartments. The shear forces and bending moments due to radiation-diffraction waves have been calculated by the direct integration of the 3-d hydrodynamic pressure on the outer and inner hulls of floating barges. The motion responses and the relative flow rate across the mean free surface of the water in the flooded compartments are also presented.

• Journal of Ship and Ocean Technology
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• v.6 no.2
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• pp.37-50
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• 2002

In the present numerical simulation of viscous free surface flow around a ship, two-fluids in-compressible Reynolds-averaged Navier-Stokes equations with the standard $\textsc{k}-\varepsilon$turbulence model are discretized on a regular grid by using a finite volume method. A local level-set method is introduced for capturing the free surface movement and the influence of the viscous layer and dynamic boundary condition of the free surface are implicitly considered. Partial differential equations in the level-set method are discretized with second order ENO scheme and explicit Euler scheme in the space and time integration, respectively. The computational results for the Series-60 model with $C_B=0.6$ show a good agreement with the experimental data, but more validation studies for commercial complicated hull forms are necessary.

• Bulletin of the Society of Naval Architects of Korea
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• v.13 no.4
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• pp.11-18
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• 1976

In 1925 Havelock compared theoretical wave resistance with experimental one varying draft, in which the two ship's forms were different from each other. So, in this paper theoretical wave resistance was compared with the experimental one on the ship of the same form. And, though Havelock calculated theoretical wave resistance by mathematical artifice, in this paper it was calculated by computer using the method of numerical integration. In Havelock's paper, the increment of wave resistance decreased when the draft increased. but in this paper the conclusion is changed: the increment of wave resistance increases when the draft increases. The reason is supposed by the effect of the displacement of the ship.