• Journal of Ocean Engineering and Technology
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• v.21 no.6
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• pp.42-46
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• 2007

The impact of a single wave generated by a dam break with a tall structure is modeled with a three-dimensional version of the Moving particle semi-implicit (MPS) method. The particle method is more feasible and effective than methods based on grid connection problems involving violent free surface motions. In the present study, the Tsunami impact load and the change of longitudinal velocity component around the structure, which are obtained from the numerical simulation, are compared to those from experiments.

• Journal of Ocean Engineering and Technology
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• v.34 no.5
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• pp.342-350
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• 2020

In this study, a hydrate inhibition system is investigated for shallow water gas fields. Mono-ethylene glycol (MEG) injection has been used as a typical method for inhibiting hydrate formation in gas fields; therefore, most offshore platforms are equipped with MEG injection and regeneration processes. A recent application of a kinetic hydrate inhibitor (KHI) has reduced the total volume of MEG injection and hence reduce the operating cost. Experiments are designed and performed to evaluate and verify the KHI performance for inhibiting hydrate formation under shallow water conditions. However, the shut-in and restart operation may require the injection and regeneration of MEG. For this operation, the MEG concentration must be optimized while considering the cost of MEG regeneration. The obtained results suggest that decreasing MEG concentration from 80 wt% to 70 wt% can reduce the life cycle cost (LCC) of MEG regeneration process by approximately 5.98 million USD owing to reduced distillation column cost. These results suggest that the hydrate inhibition system must be evaluated through well-designed experiments and process simulations involving LCC analysis.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.3
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• pp.559-579
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• 2015

An experimental study of the effect of mooring systems on the dynamics of a SPAR buoy-type floating offshore wind turbine is presented. The effects of the Center of Gravity (COG), mooring line spring constant, and fairlead location on the turbine's motion in response to regular waves are investigated. Experimental results show that for a typical mooring system of a SPAR buoy-type Floating Offshore Wind Turbine (FOWT), the effect of mooring systems on the dynamics of the turbine can be considered negligible. However, the pitch decreases notably as the COG increases. The COG and spring constant of the mooring line have a negligible effect on the fairlead displacement. Numerical simulation and sensitivity analysis show that the wind turbine motion and its sensitivity to changes in the mooring system and COG are very large near resonant frequencies. The test results can be used to validate numerical simulation tools for FOWTs.

• Journal of Ocean Engineering and Technology
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• v.33 no.3
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• pp.236-244
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• 2019

Internal waves occur at the interface between two layers caused by a seawater density difference. The internal waves generated by a body moving in a two-layer fluid are also related to the generation of surface waves because of their interaction. In these complex flow phenomena, the experimental measurements and experimental set-up for the wave patterns of the internal waves and surface waves are very difficult to perform in a laboratory. Therefore, studies have mainly been carried out using numerical analysis. However, model tests are needed to evaluate the accuracy of numerical models. In this study, the various experimental conditions were evaluated using CFD simulations before experiments to measure the wave patterns of the internal waves and surface waves in a stratified two-layer fluid. The numerical simulation conditions included variations in the densities of the fluids, depth of the two-layer fluid, and moving speed of the underwater body.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.3
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• pp.613-619
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• 2017

In this paper, DF(Dual Fuel) Generator modeling, which uses both conventional diesel fuel and LNG fuel, has been performed and monitoring system has been developed based on MATLAB/SIMULINK for the development of PMS(Power Management System) HILS(Hardware In the Loop Simulation). The principal components modeling of DF Generator are DF engine which provides the mechanical power and synchronous generator which convert the mechanical power into electrical power. Submodels, such as throttle body, intake manifold, torque generation and mass of LNG and diesel Quantity are used to perform DF engine. Also, governor is used for load sharing between paralleled DF generators to share a total load that exceeds the capacity of a single generator. To verify modeling of DF Generator designated ship lumped load Simulation is carried out. A validity of DF Generator has been verified by comparison between simulation results and estimated result from the designated lumped load.

• Korean Institute of Interior Design Journal
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• no.36
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• pp.37-43
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• 2003

This study investigates the characteristic traits of architectural design of Toyo Ito, who has been acclaimed as one of the most famous present-day Japanese architects. Ito' architecture is generally known as media architecture for its specific natures such as lightness, dematerialization, extensive use of shiny glass, etc. In this respect, Ito's architecture is a radical departure from the tradition of the architectural modernism mostly represented by Le Corbusier. In this study, the architectural world of Toyo Ito is divided into four main section: the conversation between architecture and nature, the architecture of the wind, simulation, and virtual reality, Each of these categories is given full investigation together with appropriate architectural model fit into them.

• Proceedings of the IEEK Conference
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• 2004.06a
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• pp.309-312
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• 2004

This paper proposes the architecture of UWB OFDM communication system. More high data rate is requested in the 128-point FFT/IFFT of the UWB OFDM communication system than the conventional communication systems. So, the proposed architecture uses pipeline and parallel architecture. For a highly efficient architecture, the optimal clipping power and the input quantization bits are found in simulation. The hardware complexity of the proposed architecture is presented is consideration of Adder, Register and Complex Multiplier.

• Proceedings of the SAREK Conference
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• 2004.06a
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• pp.112-112
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• 2004

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.5669-5684
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• 2018

The new mobile edge network architecture has been required for an increasing amount of traffic, quality requirements, advanced driver assistance system for autonomous driving and new cloud computing demands on highway. This article proposes a hierarchical cloud computing architecture to enhance performance by using adaptive data load distribution for buses that play the role of edge computing server. A vehicular dynamic cloud is based on wireless architecture including Wireless Local Area Network and Long Term Evolution Advanced communication is used for data transmission between moving buses and cars. The main advantages of the proposed architecture include both a reduction of data loading for top layer cloud server and effective data distribution on traffic jam highway where moving vehicles require video on demand (VOD) services from server. Through the description of real environment based on NS-2 network simulation, we conducted experiments to validate the proposed new architecture. Moreover, we show the feasibility and effectiveness for the connected car media service on highway.

• Journal of the Korea Society for Simulation
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• v.8 no.1
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• pp.35-49
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• 1999

The CC-NUMA based, distributed shared memory is an emerging architecture for multiprocessor computer systems because of its scalability and easy of programming. In this paper, we analyzed performance of a ring-based, CC-NUMA multiprocessor computer system using a commercial workload targeted for popular OLTP applications. Based on the traces collected from real machines, the characteristics of the commercial workload could be obtained. The simulation results showed that the bottleneck on the ring could be effectively removed by using a dual ring structure. We believe our simulation methodology and results will help us to design better multiprocessor computer systems for commercial application domains.