• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.1
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• pp.1-10
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• 2019

Nowadays, the study on Floating Offshore Wind Turbines (FOWTs) is being performed globally. Dozens of numerical simulation tools have been developed for designing FOWTs and simulating their performances in combined wave and wind environments. On the other hand, model tests are still required to verify the results obtained from numerical simulation tools. To predict seakeeping performance of the OC3-Hywind platform, a OC3 spar model moored by a 3-leg catenary spread mooring system with a delta connection was built with a 1/128 scale ratio. The model tests were carried out for various sea states, including rotating rotor effect with wind in the Ocean Engineering Wide Tank, University Of Ulsan (UOU). The model test results are compared with the numerical simulations by UOU in-house code and FAST.

• International Journal of Naval Architecture and Ocean Engineering
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• v.12 no.1
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• pp.636-643
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• 2020

This study developed a method for simulating greenhouse gas (GHG) emissions considering changes in conditions that may occur during the actual operation of small ships. Additionally, we analyzed and compared the results of the proposed method with that of existing emission simulations according to life-cycle assessment (LCA), thus verifying the proposed method's effectiveness. Through the results of the study, we confirmed that the proposed method improves the simulation by considering emissions due to ship operation, whereas existing methods focus on emissions caused by raw material production. Additionally, the proposed method could identify and quantify the relationship between changes in operating conditions and GHG emissions. We expect this GHG emissions simulation technique to help improve the environmental performance of ships in the future.

• Advances in nano research
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• v.13 no.2
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• pp.113-120
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• 2022

In this paper, a finite element (FE) simulation has been developed in order to examine the nonlinear stability of reinforced sandwich beams with graphene oxide powders (GOPs). In this regard, the nonlinear stability curves have been obtained asuming that the beam is under compressive loads leading to its buckling. The beam is considered to be a three-layered sandwich beam with metal core and GOP reinforced face sheets and it is rested on elastic substrate. Moreover, a higher-order refined beam theory has been considered to formulate the sandwich beam by employing the geometrically perfect and imperfect beam configurations. In the solving procedure, the utalized finite element simulation contains a novel beam element in which shear deformation has been included. The calculated stability curves of GOP-reinforced sandwich beams are shown to be dependent on different parameters such as GOP amount, face sheet thickness, geometrical imperfection and also center deflection.

• International Journal of Naval Architecture and Ocean Engineering
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• v.13 no.1
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• pp.223-235
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• 2021

The Vortex-Induced Vibration (VIV) test system on deepwater riser based on Bare Fiber Bragg Grating (BFBG) sensor technology was designed. Meanwhile, a riser VIV response numerical model was established based on the work-energy principle. The results show that the first-order vibration frequency dominates the vibration of the riser, and as the velocity increases, the dominant frequency of the riser gradually increases under the effect of different top tensions. At the same velocity, as the top tension increases step by step, the dominant frequency and fatigue damage at the same position along the axial length of the riser both gradually decreases. The model test and numerical simulation show a relatively consistent change, maintaining a high degree of agreement. The process control system based on BFBG of model test has excellent performance, and FBG sensors have great advantages in VIV test of a vertical riser in water.

• Journal of the Society of Naval Architects of Korea
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• v.45 no.2
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• pp.202-212
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• 2008

In recent days, global shipbuilding companies have been increasing their productivity or expanding their shipyards for a large amount of orders. Though, few researches about the shipyard layout designs have been studied. This research presents a simulation-based shipyard layout design framework to resolve the problems of the shipyard layout design. The shipyard layout design framework was developed on the basis of systems engineering method. The disciplined system engineering technique was guided by ISO/IEC 15288 during the planning phase of the shipyard layout design framework development. This framework suggests that how efficient and effective shipyard layout design could be got, that can satisfy the stakeholder of the layout. Furthermore, it is recommended that how the proposed shipyard layout should be verified and validated by digital simulation model. It is expected that the framework will contribute to not only the improvement of the existing shipyard but also the construction of the new shipyard.

• Wind and Structures
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• v.38 no.2
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• pp.129-146
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• 2024

Aiming at the problem of non-stationary wind field simulation of downbursts, a non-stationary down-burst generation system was designed by adding a nozzle and program control valve to the inlet of the original wall jet model. The computational fluid dynamics (CFD) method was used to simulate the downburst. Firstly, the two-dimensional (2D) model was used to study the outflow situation, and the database of working conditions was formed. Then the combined superposition of working conditions was carried out to simulate the full-scale measured downburst. The three-dimensional (3D) large eddy simulation (LES) was used for further verification based on this superposition condition. Finally, the wind tunnel test is used to further verify. The results show that after the valve is opened, the wind ve-locity at low altitude increases rapidly, then stays stable, and the wind velocity at each point fluctuates. The velocity of the 2D model matches the wind velocity trend of the measured downburst well. The 3D model matches the measured downburst flow in terms of wind velocity and pulsation characteris-tics. The time-varying mean wind velocity of the wind tunnel test is in better agreement with the meas-ured time-varying mean wind velocity of the downburst. The power spectrum of fluctuating wind ve-locity at different vertical heights for the test condition also agrees well with the von Karman spectrum, and conforms to the "-5/3" law. The vertical profile of the maximum time-varying average wind veloci-ty obtained from the test shows the basic characteristics of the typical wind profile of the downburst. The effectiveness of the downburst generation system is verified.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.3
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• pp.248-255
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• 2013

This paper proposes the architecture of the RILS (Robot-in-the-Loop-Simulation) consisting of the robot, the virtual robot, and the avatar robot which is the type of virtual robots operating according to the robot status and behavior. And the synchronization algorithm for mobilization part of the avatar robot is suggested, which reduces the difference between behaviors of the robot and those of the avatar robot. This difference occurs due to the environmental and mechanical mismatches between the robot and avatar robot. In order to reduce this difference in robots behaviors, the synchronization algorithm controls the avatar robot based on the data observed from the robot's behavior. The proposed architecture and the synchronization algorithm are validated from some simulation results.

• Journal of The Korean Digital Architecture Interior Association
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• v.11 no.1
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• pp.83-90
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• 2011

Lighting simulation is becoming increasingly more important as a method for design and evaluation. There is a wide range of packages that provide the accuracy and the usability in lighting simulation. Relux developed by Relux Informatik AG, Switzerland, Relux offers users innovative and high-performance light planning software with open interfaces and simultaneous access to the latest product data from luminaire and lamp manufacturers. The goals of this report is to explore some of the lighting simulation issues relating to Relux. It is hoped that it will provide some background information that will enable a designer and engineer to make some informed judgements on the potential of the current state-of-the-art in computer prediction of lighting in buildings and how this may be used to assist in building design.

• IE interfaces
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• v.13 no.3
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• pp.528-538
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• 2000

HLA is a general-purpose software architecture for distributed simulation designed to support a wide range of simulation approaches and application. The US DoD's HLA for modeling and simulation can certainly be regarded as the state of the art in distributed simulation. It is a mandatory standard for military simulation. The purpose of this paper is to describe applications of HLA/RTI in multiple domains across the manufacturing systems society. In many and large scale industrial systems, enormous data is generated, and is to be managed in an effective way. It needs a high performance common network library. Furthermore, it must satisfy the real function of system facilities as much as possible. The RTI is an implementation of the interface specification, provided as a set of services. Some applications focusing on the area of a small manufacturing system were demonstrated. The integration could be achieved using the HLA, together with interface modules for each of the subsystems. We have found that HLA/RTI are cable of meeting the functional requirements for a given system environment.

• Journal of the Korea Society for Simulation
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• v.11 no.2
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• pp.31-43
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• 2002

The High Level Architecture(HLA) for modeling and simulation was developed as means of facilitating interoperability among simulations and promoting reuse of simulations and their components. The purpose of this paper is to provide a summary of the latest release of the HLA concept, supporting utilities and develop the prototyped Transportation Movement Management(TMM) federation. To obtain this goal, the Federation Development and Execution Process(FEDEP) is being applied to development of TMM federation will consist of three federates. This paper outlines the rationale of our approach, describes the application of the FEDEP in the development of the federation, and provides the current status of the federation development. The resulting federation shows complete interoperability among simulation components in the TMM federation and satisfactory simulation outputs. We present a description and process of the federation and the lessons learned with the process utilization for federation development and execution. Furthermore, the issues in establishing a HLA based federation across multiple legacy simulations are discussed.