• Korean Journal of Computational Design and Engineering
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• v.15 no.3
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• pp.178-188
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• 2010

This paper addresses the problem of determining if two surfaces intersect tangentially or transversally in a mathematically consistent manner and approximating an intersection curve. When floating point arithmetic is used in the computation, due to the limited precision, it often happens that the decision for tangential and transversal intersection is not clear cut. To handle this problem, in this paper, interval arithmetic is proposed to use, which provides a mathematically consistent way for such decision. After the decision, the intersection is traced using the validated ODE solver, which runs in interval arithmetic. Then an iterative method is used for computing the accurate intersection point at a given arc-length of the intersection curve. The computed intersection points are then approximated by using a B-spline curve, which is provided as one instance of intersection curve for further geometric processing. Examples are provided to demonstrate the proposed method.

• Journal of Korean Society for Atmospheric Environment
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• v.12 no.4
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• pp.459-472
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• 1996

An experimental investigation on the wind flow over smooth bell-shaped two-dimensional hills with hill slopes (the ratio of height to half width) of 0.3 and 0.5 is performed in an atmospheric boundary-layer wind tunnel. Two categories of the models are used in the present investigation; six two-dimensional single-hills, and four continuous double-hills. The measurements of the flow field and surface static-pressure distribution are carried out over the Reynolds number (based on the hill height) of 1.9 $\times 10^4, 3.3 \times 10^4, and 5.6 \times 10^4$. The velocity profiles and turbulence characteristics are measured by the pitot-tube and X-type hot-wire anemometer, respectively. The undisturbed boundary-layer profile on the bottom surface of the wind tunnel is reasonably consistent with the power-law profile with $\alpha = 7.0 (1/\alpha$ is the power-law exponent) and shows good spanwise uniformities. The profiles of turbulent intensity are found to be consistent along the centerline of the wind tunnel. The measured non-dimensional speed-up profiles at the hill crest show good agreements with the predictions of Jackson and Hunt's linear theory. The flow separation occurs in the hill slope of 0.5, and the oil-ink dot method is used to find the reattachment points in the leeside of the hill. The measured reattachment points are compared with the numerical predictions. Comparisons of the mean velocity profiles and surface pressure distributions between the numerical predictions and the experimental results show good agreements.

• Earthquakes and Structures
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• v.3 no.3_4
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• pp.203-230
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• 2012

This paper presents results for impedance (and compliance) functions and input motions of foundations in a layered half-space computed on the basis of a procedure that combines a consistent transmitting boundary with continued-fraction absorbing boundary conditions which are accurate and effective in modeling wave propagation in various unbounded domains. The effects of obliquely incident seismic waves in a layered half-space are taken into account in the formulation of the transmitting boundary. Using the numerical model, impedance (and compliance) functions and input motions of rigid circular foundations on the surface of or embedded in a homogeneous half-space are computed and compared with available published results for verification of the procedure. Extrapolation methods are proposed to improve the performance in the very-low-frequency range and for the static condition. It is concluded from the applications that accurate analysis of foundation dynamics and soil-structure interaction in a layered half-space can be carried out using the enhanced consistent transmitting boundary and the proposed extrapolations.

• Journal of Environmental Science International
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• v.8 no.2
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• pp.211-219
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• 1999

Surface complexation models(SCMs) have been performed to predict metal ion adsorption behavior onto the mineral surface. Application of SCMs, however, requires a self-consistent approach to determine model parameter values. In this paper, in order to determine the metal ion adsorption parameters for the triple layer model(TLM) version of the SCM, we used the zeta potential data for Zeolite and Kaolinite, and the metal ion adsorption data for Pb(II) and Cd(II). Fitting parameters determined for the modeling were as follows ; total site concentration, site density, specific surface area, surface acidity constants, etc. Zeta potential as a new approach other than the acidic-alkalimetric titration method was adopted for simulation of adsorption phenomena. Some fitting parameters were determined by the trial and error method. Modeling approach was successful in quantitatively simulating adsorption behavior under various geochemical conditions.

• The Research Journal of the Costume Culture
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• v.2 no.2
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• pp.385-394
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• 1994

Data of the body surface is a necessary unit for the measuring of metabolism energy and activity energy. And also, these data are referring to check the degree of retaining warmth of clothes, to find the effect of heat insulation according to body surface, to calculate an average temperature of skin, and to study the several fields of clothing. In measuring of body surface, it si actually impossible to measure a subject's body surface in each experiment. As the experimental method, both gypsum method, by which the shape of body an be copied as it is, and the weighting method from which planed body surface area can be measured with consistent thickness of polyprophylene film as used. In fact, every female subject feels uncomfortable to measure her body surface as a naked body. There, it is providing a simple, accurate regressive equation with weight & height as variable factors in this study. This equation is as=117.02W+77.31H-3344.94 with average error : 0.1%, absolute average error : 2.07%.

• Journal of Korea Multimedia Society
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• v.24 no.11
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• pp.1472-1480
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• 2021

Image stacking technique is one of the key techniques for complex surface reconstruction. The process includes sample collection, image processing, algorithm editing, surface reconstruction, and finally reaching reliable conclusions. Since this experiment is based on laser scanning confocal microscope to collect the original contour information of the sample, it is necessary to briefly introduce the relevant principle and operation method of laser scanning confocal microscope. After that, the original image is collected and processed, and the data is expanded by interpolation method. Meanwhile, several methods of surface reconstruction are listed. After comparing the advantages and disadvantages of each method, one-dimensional interpolation and volume rendering are finally used to reconstruct the 3D model. The experimental results show that the final 3d surface modeling is more consistent with the appearance information of the original samples. At the same time, the algorithm is simple and easy to understand, strong operability, and can meet the requirements of surface reconstruction of different types of samples.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.6
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• pp.769-779
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• 2007

Statement of problem. When TiN coating is applied to the abutment screw, occurrence of greater preload and prevention of the screw loosening could be expected due to decrease of frictional resistance. However, the proper thickness of TiN coating on abutment screw has not been yet reported. Purpose. The purpose of this study is to find out the appropriate TiN coating thickness by evaluating the detorque force and the surface change of titanium abutment screw with various TiN coating thickness. Material and methods. 1. Material Thirty five non-coated abutment screws were prepared for TiN coating. TiN coatings were prepared by Arc ion plating method. Depending on the coating deposition time(CDT), experimental groups were divided into 6 groups(CDT 30min, 60min, 90min, 120min, 150min, 180min) and those of 1 group was not coated as a control group. Each group was made up of 5 abutment screws. 2. Methods FE-SEM(Field Emission Scanning Electron Microscoper) and EDX(Energy Dispersive X-ray Spectroscopy) were used to observe the surface of the abutment screw. Electric scales was used to measure the weight of the abutment screw after the repeated closing and opening of 10 trials. Detorque force was measured with digital torque gauge, at each trial. Results. 1. As the coating deposition time increased, the surface became more consistent and smooth. 2. As for the abutment screws that were TiN coated for more than 60 minutes, no surface change was found after the repeated closing and opening. 3. The TiN coated abutment screws showed less weight change than the non-coated abutment screws. 4. The TiN coated abutment screws showed higher mean detorque force than the noncoated abutment screws. 5. The abutment screw coated for 60 minutes showed the highest mean detorque force. Conclusion. The coating layer of proper thickness is demanded to obtain consistent and smooth coating surface, resistance to wear, and increased detorque force of the abutment screw. In conclusion, the coating deposition time of 60 minutes indicated improved mechanical property, when TiN coating was conducted on titanium abutment screw.

• 한국연소학회:학술대회논문집
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• 2006.10a
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• pp.177-186
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• 2006

Flame surface area is a critical parameter determining turbulent flame speed. Three-dimensionaldirect numerical simulations (DNS) were conducted to figure out the evolution process of flame surface area. Fully compressible Navier-Stokes equations are solved to reproduce premixed flame embedded in isotropic decaying turbulent flow. The tangential straining and curvature of propagating surface affect development of flame area. In this study, four different turbulent intensity flows and three different Le number flames are investigated to force changes in straining and curvature effects. Consistent results are obtained for the probability density functions (PDF) of strain and curvature with previous researches. It is revealed that displacement speed, which is a speed of flame surface relative to unburnt flow, controls the balance between sink and source of flame surface area.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.482-486
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• 1995

Generally, a great deal of attention is given to the maintenance of consistent surface roughness. Therefore one of the major goals of research in this area has been the development of models which can predict the surface roughness obtainable on a machined metal part over the simultaneous variation of cutting condition. A comparison is also made between the theoretical and actual values of surface roughness to calculate the overall variance in the developed models, Mathematical models developed from the experimental data in the course of this work can be employed to control the cutting conditions in order to achieve the desired surface roughness and deep quality.

• Journal of the Korean Society of Combustion
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• v.12 no.2
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• pp.10-19
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• 2007

Flame surface area is a critical parameter determining turbulent flame speed. Three-dimensional direct numerical simulations(DNS) were conducted to figure out the evolution process of flame surface area. Fully compressible Navier-Stokes equations are solved to reproduce premixed flame embedded in isotropic decaying turbulent flow. The tangential straining and curvature of propagating surface affect development of flame area. In this study, four different turbulent intensity flows and three different Le number flames are investigated to force changes in straining and curvature effects. Consistent results are obtained for the probability density functions (PDF) of strain and curvature with previous researches. It is revealed that displacement speed, which is a speed of flame surface relative to unburnt flow, controls the balance between sink and source of flame surface area.