• Journal of KIISE:Computer Systems and Theory
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• v.36 no.5
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• pp.335-343
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• 2009

The crossed cube has received great attention because it has equal or superior properties compared to the hypercube that is widely known as a versatile parallel processing system. It has been known that disjoint two copies of a mesh of size $4{\times}2^m$ or disjoint four copies of a mesh of size $8{\times}2^m$ can be embedded into a crossed cube with dilation 1 and expansion 1 [Dong, Yang, Zhao, and Tang, 2008]. However, it is not known that disjoint multiple copies of a mesh with more than eight rows and columns can be embedded into a crossed cube with dilation 1 and expansion 1. In this paper, we show that disjoint $2^{n-1}$ copies of a mesh of size $2^n{\times}2^m$ can be embedded into a crossed cube with dilation 1 and expansion 1 where $n{\geq}1$ and $m{\geq}3$. Our result is optimal in terms of dilation and expansion that are important measures of graph embedding. In addition, our result is practically usable in allocating multiple jobs of mesh structure on a parallel computer of crossed cube structure.

• Steel and Composite Structures
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• v.18 no.6
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• pp.1391-1404
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• 2015

A radially retractable roof structure based on the concept of the hybrid grid shell is proposed in this paper. The single-layer steel trusses of the radially foldable bar structure are diagonally stiffened by cables, which leads to a single-layer lattice shell with triangular mesh. Then comparison between the static behavior between the retractable hybrid grid shell and the corresponding foldable bar shell with quadrangular mesh is discussed. Moreover, the effects of different structural parameters, such as the rise-to-span ratio, the bar cross section area and the pre-stress of the cables, on the structural behaviors are investigated. The results show that prestressed cables can strengthen the foldable bar shell with quadrangular mesh. Higher structural stiffness is anticipated by introducing cables into the hybrid system. When the rise-span ratio is equal to 0.2, where the joint displacement reaches the minimal value, the structure shape of the hyrbid grid shell approaches the reasonable arch axis. The increase of the section of steel bars contributes a lot to the integrity stiffness of the structure. Increasing cable sections would enhance the structure stiffness, but it contributes little to axial forces in structural members. And the level of cable prestress has slight influence on the joint displacements and member forces.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.247-250
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• 2007

Flexible media such as the paper, the film, etc. are thin, light and very flexible. They behave in geometrically nonlinear. Any of small force makes large deformation. So we must including aerodynamic effect when its behavior is predicted. Thus, it becomes fully coupled fluid-structure interaction(FSI) problem. In FSI problems, where the fluid mesh near the structure undergoes large deformations and becomes unacceptably distorted, which drive the time step to a very small value for explicit calculations, the arbitrary Lagrangian-Eulerian(ALE) methods or rezoning are used to create a new undistorted mesh for the fluid domain, which allows the calculations to continue. In this paper, FE sheet model considering geometric nonlinearity is formulated to simulate the behavior of the flexible media. Aerodynamic force to the media by surrounding air is calculated by solving the incompressible Navier-Stokes equations. Q2Q1(Taylor-Hood) element which means biquadratic for velocity and bilinear for pressure is used for fluid domain. Q2Q1 element satisfies LBB condition and any stabilization technique is not needed. In this paper, cantilevered sheet in the viscous incompressible Navier-Stokes flow is simulated to check the mesh motion and numerical integration scheme, and then falling paper in the air is simulated and the effects of some representative parameters are investigated.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05b
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• pp.213-217
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• 2009

Underground structures are built into concrete like a architecture and public works. Concrete has watertightness as such, But buildings are leaking from the cracks. Recently, construction method do a lot of close construction in the downtown area. So architects are using the method for the outer layer of a two-layer wall to save spaces. They have been using Top-down method and waterproof agent method and others to outer layer of a two-layer wall method. But, There are many leakage in underground structure from lack on requirements performance of materials. Therefore, I hope to test the outside Waterproof Method of Ground using Wire-mesh and Non-hardening Viscosity Waterproof. In addition to, I wish to apply as outside waterproof method for the section for the outer layer of a two-layer wall in underground structure.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.68 no.1
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• pp.207-214
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• 2019

A large-capacity wireless power system is a technology that transmits electric power of kW or more in a noncontact type. Electric cars, electric buses, and electric railways. In order to increase the power transmission efficiency, a resonance method using a frequency of kHz is applied and the efficiency is 80 ~ 90%. In this case, the loss is 10 ~ 20% other than efficiency, and corresponds to several hundreds of W to several kW in kW class wireless power transmission. 35 kW wireless feed system environment, and induced current in the nearby conductive part was measured. As a result of analysis, it was confirmed that induction phenomenon is higher as the loop configuration of the conductive part per area is dense. The increase of the induced current in the mesh loop is characterized by the density of the nearby conductive part having a permeability per unit area. The concentration of the magnetic field by the permeability is increased and the induction phenomenon causing the induction current is increased. It was confirmed that induction phenomenon increases by about 2.7 times when 9 times dense structure is formed.

• 한국전산유체공학회:학술대회논문집
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• 2006.05a
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• pp.219-222
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• 2006

• Journal of Powder Materials
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• v.2 no.2
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• pp.135-141
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• 1995

As the first step of study on fabrication of ceramic powders from phytoliths in rice, especially in rice husks, pulverization method of rice husks and the properties of milled rice husks were investigated. Impact methods, such as ball milling, were not meaningful for pulverizing elastic and thin fabric structure of rice husks. The most effective one was cutting method. In the present work, a rotating knife cutting method was applied to pulverizing rice husks. A 40-mesh screen was inserted under the rotating knives. The most portion of the milled powder was found in -50/+100 mesh section. Morphology of the milled rice husks revealed that the husks larger than 70 mesh were flake-like shape, at -70/+100 mesh section relatively equi-axed shape, at -170/+325 mesh section rod-like shape, and below 325 mesh section dust-like shape. Tap density of raw rice husks was about 0.1 $g/cm^3$, while those of milled rice husks were over $0.4 g/cm^3$. This meant that, for a given volume of reactor, raw material charge can be increased more that 4 times when using milled rice husks than unmilled one. True densities of unmilled and milled rice husks were higher than $1.4 g/cm^3$, and increased with decreasing milled sizes.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.3
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• pp.14-19
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• 2010

Partial anodic oxidation of Ti-mesh with a wire diameter of ~200[${\mu}m$] produces self-aligned $TiO_2$ nanotube arrays (~50[${\mu}m$] in length) on Ti-mesh substrate. The electrolyte used for anodic oxidation was an ethylene glycol solution with an addition of 1.5 vol. % $H_2O$ and 0.2 wt. % $NH_4F$. A dye-sensitized solar cell utilizing the photoanode structure of $TiO_2$-nanotube/Ti-mesh was fabricated without a transparent conducting oxide (TCO) layer, in which Ti-mesh replaced the role of TCO. The 1.93[%] photoconversion efficiency was low, which can be attributed to both insufficient dye molecules attachment and limited electrolyte flow to dye molecules. The optimized nanotube diameter and length as well as the $TiCl_4$ treatment can improve cell performance.

• International Journal of Aeronautical and Space Sciences
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• v.10 no.2
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• pp.95-105
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• 2009

The flow fields around the HARTII rotor were numerically investigated using a viscous flow solver on adaptive unstructured meshes. An overset mesh and a deforming mesh technique were used to handle the blade motion including blade deflection, which was obtain from the HARTII experimental data. A solution-adaptive mesh refinement technique was also used to capture the rotor wake effectively. Comparison of the sectional normal force and pitching moment at 87% radial station between the two cases, with and without the blade deflection, showed that the blade loading is significantly affected by blade torsion. It was found that as the mesh was refined, the strength of tip vortex is better preserved, and the magnitude of high frequency blade loading, caused by blade-vortex interaction (BVI), is further magnified. It was also found that a proper time step size, which corresponds to the cell size, should be used to predict unsteady solutions accurately. In general, the numerical results in terms of the unsteady blade loading and the rotor wake show good agreement with the experimental data.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.2
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• pp.197-203
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• 2000

Maxillary defect may be induced by trauma, inflammation, cyst, tumor and surgical procedure. In case of limited wall defect, free bone graft has been preferred. But it has some problems such as postoperative bone resorption and soft tissue inclusion to recipient site. And we can not use free bone in the case who has inflammation in the donor site. So we used the micro-titanium mesh as reconstructive material for the maxillary wall defect. We had operated 8 patients who were diagnosed as maxillary partial defects from June 1997 to September 1998 in the Chin-Hae military hospital. They were 1 case of antral wall defect, 1 case of palatal wall defect, 5 cases of infra-orbital wall defects and 1 case of oroantral fistula case. As a result, the micro-titanium mesh has shown the morphological stability and biocompatibility and it could be used in case who has infection. And mesh structure could prevent soft tissue ingrowth to bony defect area. Thus it can be used to the case of maxillary partial defect successfully.