• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.05a
• /
• pp.772-777
• /
• 2002

A BEM is highly efficient method in the sense of economic computation. However, boundary integration is not easy for the complex and moving surface e.g. in a rotating blade. Thus, Kirchhoff surface is designed in an effort to overcome the difficulty resulting from complex boundary conditions. A Kirchhoff surface is a fictitious surface which envelopes acoustic sources of main concern. Acoustic sources may be distributed on each Kirchhoff surface element depending on its acoustic characteristics. In this study, an axial fan is assumed to have loading noise as a dominant source. Dipole sources can be computed based on the FW-H equation. Acoustic field is then computed by changing Kirchhoff surfaces on which near-field is implemented, to analyze the effect of Kirchhoff surface on it.

• Journal of the Korea Society of Computer and Information
• /
• v.19 no.2
• /
• pp.11-19
• /
• 2014

In this paper, we build server consolidate virtualization focusing on NT server dilapidated and through analysis of the effect of this, has been presented the following results. First, it was possible to obtain an increase in the constant temperature constant humidity chamber efficiency by securing the upper surface space for computing data center mounted virtualization integration server servers multiple physical. Second, by the deployment of virtualization of a large server dilapidated, the introduction of new resources and the cost of maintaining computerized data center and reduce power consumption, the reduction of hardware introduction of additional due to the new server deployment it was possible to derive a cost reduction effect. We obtain the reduction of 89% and 79% compared with conventional consumption of cooling and power savings of the top surface, respectively. Integration of NT servers are virtualized can be expected to change in the Green-IT to contribute to providing the maintenance costs of computing centers in the future as well as current. Building a virtualization server integration applied in this paper can be similarly applied to the UNIX system and to integrate the server group other.

• Korean Journal of Soil Science and Fertilizer
• /
• v.48 no.5
• /
• pp.522-527
• /
• 2015

Decision of available soil depth based on soil physical and hydraulic properties for the $3^{rd}$ Landscape Vegetation Project in the Incheon International Airport was attempted. The soil samples were collected from the 8 sites at different depths, 0-20 and 20-60cm, for the three project fields, A, B, and C area. Physical and chemical properties including particle size distribution, organic matter content and electrical conductivity were analyzed. Hydrological properties including bulk density and water holding capacity at different water potential, -6 kPa, -10 kPa, -33 kPa, and -1500 kPa were calculated by SPAW model of Saxton and Rawls (2006), and air entry value was calculated by Campbell model (1985). Based on physical and hydrological limitation, feasibility and design criteria of soil depth for vegetation and landfill were recommended. Since the soil salinity of the soil in area A area was $19.18dS\;m^{-1}$ in top soil and $22.27dS\;m^{-1}$ in deep soil, respectively, landscape vegetation without amendment would not be possible on this area. Available soil depth required for vegetation was 2.51 m that would secure root zone water holding capacity, capillary fringe, and porosity. Available soil depth required for landscape vegetation of the B area soil was 1.51 m including capillary fringe 0.14 m and available depth for 10% porosity 1.35 m. The soils in this area were feasible for landscape vegetation. The soil in area C was feasible for bottom fill purpose only due to low water holding capacity.

• Design & Manufacturing
• /
• v.18 no.2
• /
• pp.9-16
• /
• 2024

Recently, there has been extensive research conducted on the miniaturization of semiconductors and the improvement of their integration to achieve high-quality and high-performance electronic devices. To integrate and miniaturize multiple semiconductors, thin and precise wafers are essential. The backgrinding process, which involves high-precision processing, is necessary to achieve this. The backgrinding system is used to grind and polish the back side of the wafer to reduce its thickness to ㎛ units. This enables the high integration and miniaturization of semiconductors and a flattening process to allow for detailed circuit design, ultimately leading to the production of IC chips. As the backgrinding system performs precision processing at the ㎛ unit, it is crucial to determine the stability of the equipment's rigidity. Additionally, the flatness and surface roughness of the processed wafer must be checked to confirm the processability of the backgrinding system. IIn this paper, the goal is to verify the processability of the back grinding system by analyzing the natural frequency and resonance frequency of the equipment through computer simulation and measuring and analyzing the flatness and surface roughness of wafers processed with backgrinding system. It was confirmed whether processing damage occurred due to vibration during the backgrinding process.

• The Journal of the Korea Contents Association
• /
• v.9 no.4
• /
• pp.34-44
• /
• 2009

Integrating 3D data acquired in multiple views is one of the most important techniques in 3D modeling. However, due to the presence of surface scanning noise and the modification of vertices consisting of surface, the existing integration methods are inadequate to some applications. In this paper, we propose a method of integrating surfaces by using the local surface topology. We first find all boundary vertex pairs satisfying a prescribed geometric condition on adjacent surfaces and then compute 2D planes suitable to each vertex pairs. Using each vertex pair and neighbouring boundary vertices projected to their 2d plane, we produce polygons and divide them to the triangles which will be inserted to empty space between the adjacent surfaces. A proposed method use local surface topology and not modify the vertices consisting of surface to integrate several of surfaces to one surface, so that it is robust and simple. We also integrate the transformed textures to a 2D image plane computed by using a cylindrical projection to composite 3D textured model. The textures will be integrated according to the partition lines which considering attribute of face object. Experimental results on real object data show that the suggested method is simple and robust.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2007.05a
• /
• pp.272-275
• /
• 2007

This paper is concerned with modified integration algorithm on the strain-space for rate and temperature dependent elasto-plastic constitutive relations in order to obtain more accurate results in numerical implementation. The proposed algorithm is integrated analytically using integration by part and chain rule and then is applied to the 2-stage Lobatto IIIA with second-order accuracy. It has advantage that is able to consider the convective stress rates on the yield surface of the strain-space. Also this paper is carried out the iteration procedure using the Newton-Raphson method to enforce consistency at the end of the step. And the performance of the proposed algorithm for rate and temperature dependent constitutive relation is illustrated by means of analysis of adiabatic shear bands.

• Structural Engineering and Mechanics
• /
• v.8 no.6
• /
• pp.591-605
• /
• 1999

An accurate and efficient shell element is presented. The stiffness of the shell element is decomposed into two parts with one part corresponding to stretching and bending deformation and the other part corresponding to shear deformation of the shell. Both parts of the stiffness are calculated with reduced integration rules, thereby improving computational efficiency. Shear strains are averaged on the reference surface such that neither locking phenomena nor any zero energy mode can occur. The satisfactory behaviour of the element is demonstrated in several numerical examples.

• Proceedings of the IEEK Conference
• /
• 2002.06a
• /
• pp.191-194
• /
• 2002

We analyzed radiation characteristics of dipole antenna in a lossy 9round with conducting object located above ground. Electric field integral equation is used to solve the problem. In this integral equation, GPOF(Generalized Pencil of Function) method is applied to derive the closed form of the electric field due to a current source. Surface current on a conductor is expanded with a well-known vector triangle basis function. The singular integration of a triangle patch is transformed to the non-singular integration by Duffy's method. This transformed non-singular integration is easily calculated by using one-dimensional Gaussian quadrature rule, instead of usual closed form evaluation.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.472-475
• /
• 2003

Electric Power Steering (EPS) mechanism has become widely equipped in passenger vehicle due to the environmental consciousness and higher fuel efficiency. This paper describes the development of co-simulation technique and simulation integration technique of EPS control system with dynamic vehicle model. A full vehicle model interacted with EPS control algorithm is concurrently simulated on a single bump road condition. Dynamic responses of vehicle chassis and steering system resulting from road surface impact are evaluated and compared with proving ground experimental data. The comparisons will show reasonable agreement on tie-rod load. rack displacement, handle-wheel torque and tire center acceleration. This developed simulation capability can be used for EPS performance evaluation and calibration as well as for vehicle handling performance integration and synthesis.

• Journal of Ship and Ocean Technology
• /
• v.5 no.1
• /
• pp.38-54
• /
• 2001

A finite difference method for calculating turbulent flow and surface wave fields around a ship model is evaluated through the comparison with the experimental data of a Series 60 $C_B$=0.6 ship model. The method solves the Reynolds-averaged Navior-Stokes Equations using the non-staggered grid system, the four-stage Runge-Kutta scheme for the temporal integration of governing equations and the Bladwin-Lomax model for the turbulence closure. The free surface waves are captured by solving the equation of the kinematic free-surface condition using the Lax-Wendroff scheme and free-surface conforming grids are generated at each time step so that one of the grid surfaces coincides always with the free surface. The computational results show an overall close agreement with the experimental data and verify that the present method can simulate well the turbulent boundary layers and wakes as well as the free-surface waves.