• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.359-361
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• 2001

In this paper, 3-dimensional charge simulation method was applied to analyze electric field distributions of special conductor bundles equipped with spiral rods for reducing aeolian noise in a corona cage. We found calculation error of this method was w a reasonable boundary of 0.5%.

• Earthquakes and Structures
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• v.16 no.2
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• pp.221-234
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• 2019

Today, many important concrete face rockfill dams (CFRDs) have been built on the world, and some of these important structures are located on the strong seismic regions. In this reason, examination and monitoring of these water construction's seismic behaviour is very important for the safety and future of these dams. In this study, the nonlinear seismic behaviour of Ilısu CFR dam which was built in Turkey in 2017, is investigated for various reservoir water heights taking into account 1995 Kobe near-fault and far-fault ground motions. Three dimensional (3D) finite difference model of the dam is created using the FLAC3D software that is based on the finite difference method. The most suitable mesh range for the 3D model is chosen to achieve the realistic numerical results. Mohr-Coulomb nonlinear material model is used for the rockfill materials and foundation in the seismic analyses. Moreover, Drucker-Prager nonlinear material model is considered for the concrete slab to represent the nonlinearity of the concrete. The dam body, foundation and concrete slab constantly interact during the lifetime of the CFRDs. Therefore, the special interface elements are defined between the dam body-concrete slab and dam body-foundation due to represent the interaction condition in the 3D model. Free field boundary condition that was used rarely for the nonlinear seismic analyses, is considered for the lateral boundaries of the model. In addition, quiet artificial boundary condition that is special boundary condition for the rigid foundation in the earthquake analyses, is used for the bottom of the foundation. The hysteric damping coefficients are separately calculated for all of the materials. These special damping values is defined to the FLAC3D software using the special fish functions to capture the effects of the variation of the modulus and damping ratio with the dynamic shear-strain magnitude. Total 4 different reservoir water heights are taken into account in the seismic analyses. These water heights are empty reservoir, 50 m, 100 m and 130 m (full reservoir), respectively. In the nonlinear seismic analyses, near-fault and far-fault ground motions of 1995 Kobe earthquake are used. According to the numerical analyses, horizontal displacements, vertical displacements and principal stresses for 4 various reservoir water heights are evaluated in detail. Moreover, these results are compared for the near-fault and far-faults earthquakes. The nonlinear seismic analysis results indicate that as the reservoir height increases, the nonlinear seismic behaviour of the dam clearly changes. Each water height has different seismic effects on the earthquake behaviour of Ilısu CFR dam. In addition, it is obviously seen that near-fault earthquakes and far field earthquakes create different nonlinear seismic damages on the nonlinear earthquake behaviour of the dam.

• Korean Journal of Heritage: History & Science
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• v.47 no.2
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• pp.68-84
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• 2014

The royal tombs of Baekje(백제), after the transfer of the capital to the Geumgang(riv)(금강) basin, changed to Songsanri(송산리) style(stone chamber) ${\rightarrow}$ Southern dynastic(남조) style(brick chamber) ${\rightarrow}$ Neungsanri(능산리) style(stone chamber). The most special feature of this process is the change of the ceiling structure. The ceiling had been changed from dome(Songsanri style) ${\rightarrow}$ tunnel ceiling(transition period of brick tombs and Neungsanri style) ${\rightarrow}$ a roof style(is Neungsanri style of three imitate type, trapezoid, triangle, flattened ceiling). The most special feature among this process is Neungsanri style(stone chamber), created especially in Baekje. The royal tombs of Baekje didn't lay stress on the mound, so the mound is not noticeable. It is result that they more stressed on basin of the boundary than showed off individual tomb, and this is count as an element of China Southern dynasty. Boundary of the royal tomb of Baekje, after the transfer of the capital to south, were changed from royal family's boundary to single independent's. Those are Songsanri's and Neungsanri's, these are the pair tombs(쌍릉) of Iksan(익산). That is influence of the Southern dynasty, reflect the theory of divination based on topography completely, this is influence of the China Sui(수) and the early Tang(당) dynasty's system of boundary of the royal tomb. Besides the royal tomb, they also buried a closely related person, in the boundary of the royal tomb. And facilities for memorial ceremony were existed too. An altar was equipped in Songsanri's boundary of the royal tomb, it was seen a kind of character of a sanctuary for progenitor. Neungsanri's boundary of the royal tomb were equipped with an open-aired altar that performed memorial ceremony about communal royal tombs, and also equipped a temple, was needed to pray for the happiness of the dead. This structure and arrangement are very similar to Seoakdong(서악동) of Silla(신라).

• Land and Housing Review
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• v.7 no.1
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• pp.31-41
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• 2016

In this paper, we propose experimental results, which target the major variables that influence the structural performance of a wall, as well as the resulting seismic and hysteretic behavior. Results also provide the basis for the application of performance based design by identifying the nonlinear hysteretic behavior of the wall with boundary element details recently proposed in previous study by Chun et al(2011). From the experimental results, the crack and fracture patterns of a specimen, which adopt the proposed boundary element details, showed similar tendencies regardless of whether axial force or high performance steel bars is applied. Furthermore, results show that the maximum strength of the specimen can be predicted accurately based on the design equation proposed by the standard. In addition, with a higher axial force, there is a tendency that both the initial load and maximum strength increase as deformation capacity reduces, requiring consideration of the reduced deformation capacity due to a high axial force. For walls under such high axial forces, using high performance steel bars is a very effective manner of enhancing deformation capacity. Therefore, reinforcing the plastic hinge region with boundary elements using high performance steel bars is preferable.

• Transactions of the Korean Society of Mechanical Engineers
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• v.4 no.4
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• pp.152-159
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• 1980

The temperature and the grain boundary precipitation have the great influence on the low-cycle fatigue behavior of austenite stainless steel at elevated temperature. For the purpose of investigating the mechanism concerning the change of fatigue micro crack mode in SUS 316 under various conditions low-cycle fatigue test was carried out at the elevated temperature 600.deg.C, plastic strain range 2% and constant strain rate .5c.p.m. A special attention is given to the observation of intergranular crack initiation. The results obtained are summarized as follows. The low-cycle fatigue behavior of SUS 316 at 600.deg.C is affected by transition of crack initiation mode from intergranular to transgranular. The transition is due to the aging effect, which is caused by grain boundary precipitations of Cr$\_$23/C$\_$6/. Since the intergranular crack initiation is brought about by the grain boundary sliding, the transgranular crack initiates in case that the strengthening of grain boundary due to the precipitation of Cr$\_$23/C$\_$6/ carbides takes place ahead of the intergranular crack initiation.

• Ocean and Polar Research
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• v.29 no.1
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• pp.55-67
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• 2007

A reference to natural prolongation appeared for the first time in the North Sea Judgement. Although it was not suggested that the concept of natural prolongation would automatically allow for the fixing of a continental shelf boundary, that concept encouraged States to request international tribunals to determine continental shelf boundaries on the basis of the geological and geomorphological features of the seabed. In the Libya v. Malta Case, however, the rejection of geological and geomorphological factors was total. Especially, Natural prolongation was the then checkmated as a relevant fact in delimitation between coasts situated less than 400 nm. apart. There can be no doubt that, in several disputed cases, prominent geomorphological variations are simply ignored ; nevertheless, there are also a few agreements where geological and geomorphological characteristics come into play and, to a certain extent, affect maritime boundaries. Physical characteristics of sea-bed are generally given serious consideration in the boundary delimitation such as the final negotiated boundary of the Australia-Indonesia Continental Shelf boundary Agreement(Timor and Arafura seas) which follows the continental slope bordering the Timor Trench.

• Journal of Ocean Engineering and Technology
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• v.36 no.6
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• pp.353-363
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• 2022

The azimuth thruster is mainly installed on a vessel that requires a dynamic positioning (DP) function for special purposes. When the azimuth thruster on a vessel operates for DP, the thrust loss is induced by the thruster-hull interaction. This study examined the influence of boundary conditions in numerical simulations for predicting thrust loss. Wind turbine installation vessels (WTIV) and floating production storage and offloading (FPSO) were chosen as a target vessels. In this study, two types of boundaries were defined. The first consideration is that the boundary condition was assigned with consideration of the azimuth angle of the thruster, whereas it is fixed regardless azimuth angle of the thruster. The predicted thrust loss according to these boundary conditions showed a difference. This observation originated from the current load of the vessel. Therefore, the boundary conditions for which the current load is not induced need to be designated to obtain a realistic thrust loss in a numerical simulation.

• Journal of the Korean Mathematical Society
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• v.37 no.5
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• pp.665-685
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• 2000

The aim of this paper is to obtain nonlinear operators in suitable spaces whise fixed point coincide with the solutions of the nonlinear boundary value problems ($\Phi$($\upsilon$'))'=f(t, u, u'), l(u, u') = 0, where l(u, u')=0 denotes the Dirichlet, Neumann or periodic boundary conditions on [0, T], $\Phi$: N N is a suitable monotone monotone homemorphism and f:[0, T] N N is a Caratheodory function. The special case where $\Phi$(u) is the vector p-Laplacian $\mid$u$\mid$p-2u with p>1, is considered, and the applications deal with asymptotically positive homeogeneous nonlinearities and the Dirichlet problem for generalized Lienard systems.

• The KSFM Journal of Fluid Machinery
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• v.13 no.2
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• pp.12-17
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• 2010

A kind of disk-shape boundary layer pump is designed numerically by using a software of computational fluid dynamics, which is widely used for the special purposes such as artificial hearts, bio-fluidics and transportation of oceanic lives, etc. From the numerical simulation with an axisymmetric model, some benchmark problems are tested and compared with experimental results. The performance of disk pump is graphically visualized from the computational results, and converted to the dimensionless parameters. Finally, the obtained numerical data in the present investigation can be used for the baseline for new design to achieve a more efficient disk pump.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.13 no.2
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• pp.100-108
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• 2001

Along the shoreline a special treatment is required to simulate movement of periodic waves such as tsunami and tide because of continuous movement of shoreline as waves rise and recede. A moving boundary treatment is first proposed to track the movement of shoreline in this study. The treatment is then employed to obtain a maximum inundation area to be used for mitigation of coastal flooding. The obtained maximum inundation zone for a specific location is compared to that of available observed data. A reasonable agreement is observed.