• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.385-392
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• 2003

Traditional forms of river and coastal structures have become very expensive to build and maintain, because of the shortage of natural rock. Geotextile tubes hydraulically or mechanically filled with dredged materials have been applied in hydraulic and coastal engineering in recent years(shore protection structure, detached breakwater, groins and jetty). Recently, new preliminary design criteria supported by model and prototype tests, and some stability analysis calculations have been studied. In this study, the numerical analysis was performed to investigate the behavior of geotextile tube with various properties of geotextile and hydraulic pumping conditions. Numerical analysis was executed to compare with the results from the large-scale field model tests, and also compared the results of 2-D plane strain analysis and 3-D FEM analysis. A geotextile tube was modeled using the commercial finite element analysis program ABAQUS and the one-quarter of tube was modeled. Behavior of geotextile tube during the hydraulic pumping procedure was analyzed by comparing the large-scale field model test and numerical analysis. The shape variation and maximum tube height between the numerical analysis results and large-scale filed test results are turned out to be a good agreement.

• Journal of the Korean housing association
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• v.21 no.6
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• pp.81-90
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• 2010

The existing most studies on the apartment sales prices have been limited to relatively small size apartment complexes and have not categorized the apartment complexes based on the number of households. Some of them uses the apartment-related indices such as regional value estimates, sales unit price, and view right values. In the case of Seoul Metropolitan Area, the size of apartment complex has been growing to the level of large complex over more than 1,000 households through new town development, redevelopment and reconstruction. People prefers to choose a large scale complex instead of small complex based on their perception that a large scale apartment complex provides more conveniences in living. The result of this analysis revealed that the variables chosen as important determinants of the hedonic price model for large scale apartment complexes were square meters of apartment unit, rent/price ratio, number of bays, distance to the nearest subway station, and heating system method. This means that the sales price of apartment unit will be higher as the square meters of apartment unit increase, as the rent/price ratio decreases, as the distance to the nearest subway station increases, and as the number of bays increase.

• Nuclear Engineering and Technology
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• v.55 no.9
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• pp.3367-3382
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• 2023

Smoothed Particle Hydrodynamics (SPH) is a Lagrangian computational fluid dynamics method that has been widely used in the analysis of physical phenomena characterized by large deformation or multi-phase flow analysis, including free surface. Despite the recent implementation of eddy-viscosity models in SPH methodology, sophisticated turbulent analysis using Lagrangian methodology has been limited due to the lack of computational performance and numerical consistency. In this study, we implement the standard and dynamic Smagorinsky model and dynamic Vreman model as sub-particle scale models based on a weakly compressible SPH solver. The large eddy simulation method is numerically identical to the spatial discretization method of smoothed particle dynamics, enabling the intuitive implementation of the turbulence model. Furthermore, there is no additional filtering process required for physical variables since the sub-grid scale filtering is inherently processed in the kernel interpolation. We simulate lid-driven flow under transition and turbulent conditions as a benchmark. The simulation results show that the dynamic Vreman model produces consistent results with experimental and numerical research regarding Reynolds averaged physical quantities and flow structure. Spectral analysis also confirms that it is possible to analyze turbulent eddies with a smaller length scale using the dynamic Vreman model with the same particle size.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1997.04a
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• pp.257-264
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• 1997

Seismic responses of the Hualien large scale seismic test model on a layered soil site are estimated for two recorded earthquakes and the analysis results are then compared and evaluated with the recorded responses. The method adopted for the analysis is based on substructuring method using a lumped parameter model in both the frequency and time domain. the study results indicate that the proposed method can reasonably estimate the earthquake responses of a soil-structure interaction system for engineering purposes.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.11
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• pp.507-517
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• 2005

This paper presents the results of critical contingency analysis for the Korean power system which is performed to identify the impact of the critical contingencies on the Korean power system and set up a short term system operation planning for the purpose of preventing large scale blackout. The static and dynamic simulation is carried out for each critical contingency and the simulation results for each contingency are shown under the peak load condition for the year 2005, 2007 and 2010.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.12
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• pp.1535-1542
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• 2012

A Heat Recovery Steam Generator(HRSG) is the main component of a Combined Cycle Power Plant(CCPP). It is a very large structure that is made from relatively thin metal sheets. Therefore, the structural integrity of an HRSG is very important to ensure safe operation during plant lifetime. In particular, thermal deformation and thermal fatigue have been revealed as the main causes of the mechanical degradation of an HRSG. In order to prevent unexpected damage, safety evaluation based on a large-scale analysis is necessary. Therefore, this study aims to improve the safety of HRSG by using Finite Element Analysis(FEA) results derived from large-scale analysis. Furthermore, the modified design is verified by comparing it with the original one. This result will be used as basic data for improving the safety of a vertical-type HRSG.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.1
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• pp.58.2-58.2
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• 2011

Park, Gott, & Choi (2008) found that when a galaxy is located within the virial radius from its closest neighbor and the neighbor is an elliptical, the probability of the galaxy to be an elliptical is very sensitive to the large-scale background density over a few Mpc scales. They suggested that the large-scale dependence can be arise if the temperature of a diffuse hot gas held by elliptical galaxies are higher in higher density environment. In this study, to understand the large-scale environment affects the X-ray properties of individual galaxies, we investigated the dependence of the X-ray luminosities of the elliptical galaxies on the large-scale environment using X-ray and optical data which we selected from the ROSAT All-Sky Survey and the Sloan Digital Sky Survey Data Release 7. To exclude galaxies embedded in an intra-group/cluster medium which could enhance their observed X-ray luminosity, we used isolated elliptical galaxies.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.64.3-65
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• 2020

It has been studied that galaxies evolve following a typical trajectory on the phase space under the influence of deep gravitational potential of galaxy clusters. Similarly, the large-scale filaments could also affect the evolution of galaxies before falling into the clusters. In this study, using a dark matter-only cosmological simulation, N-Cluster Run, we explore the evolution of galaxies on the phase space drien by large-scale filaments. We find that galaxies around the filaments form a common trajectory on the phase space as well as cluster galaxies do. We also examine how these trajectories change depending on various physical parameters such as galaxy mass, initial distance of galaxies from large-scale filaments, and cluster mass.

• The Journal of the Korea Contents Association
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• v.13 no.10
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• pp.565-573
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• 2013

Uncertainty in large-scale tourism development is the main reason of the delay on the project. The purpose of this study is to identify the status and effect of this large-scale tourism development project. Huge amount of funds has to be invested prior to the development of this project and with high uncertainty of successful development, the procedure is the most important factor of this project. Therefore, under the basis of these assumptions, we operated a PLS regression analysis to see any factors that has influence during the procedure of the project. The result of the PLS regression analysis resulted that among all of the factors, the participation and role of regional community is the highest priority. In order to lead large-scale tourism development to success is to listen to the ideas of various project-related personnels and form a public - private partnership for evaluation of the project.

• International Journal of Advanced Culture Technology
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• v.9 no.4
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• pp.268-273
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• 2021

In this paper, we propose a sentiment analysis model that improves performance on small-scale data. A sentiment analysis model for small-scale data is proposed and verified through experiments. To this end, we propose Bagging-Bi-GRU, which combines Bi-GRU, which learns GRU, which is a variant of LSTM (Long Short-Term Memory) with excellent performance on sequential data, in both directions and the bagging technique, which is one of the ensembles learning methods. In order to verify the performance of the proposed model, it is applied to small-scale data and large-scale data. And by comparing and analyzing it with the existing machine learning algorithm, Bi-GRU, it shows that the performance of the proposed model is improved not only for small data but also for large data.