• Communications of the Korean Mathematical Society
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• v.11 no.2
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• pp.349-357
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• 1996

Using a special property of Bloch functions with Hardmard gaps and using the geometric properties of the self maps of the unit disc, we give a way of constructing explicit examples of Bloch functions f whose derivative is in $H^p$ (0 < p < 1) but $f \notin BMOA$.

• East Asian mathematical journal
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• v.38 no.3
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• pp.331-338
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• 2022

In this paper, we prove that the first nonzero eigenvalues λ₁ of the Laplacian and the p-Laplacian are decreasing along the inverse mean curvature flow with forced term in Euclidean space.

• The Korean Journal of Community Living Science
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• v.25 no.3
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• pp.383-388
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• 2014

This study was examined the physical characteristics (geometry, yield strength, thousand-seeds weight, true density, and moisture content) required for mechanization-related technologies such as (harvesting, washing, transport, and drying). Large differences in the size and shape of boxthorn berries(Jangmyeong, Bullo, Chungmyeong, and Hokwang) are used to analyze these physical properties. The average diameter, volume, surface area, and sphericity rate are calculated using long and short diameters of the boxthorn berry according to its variety. Hokwang has the largest measured surface area, and Bullo, the smallest. Average yield strength is 1.78 kPa and the mechanical pressure of soft boxthorn berries is not more than 1 kPa. Bullo has the highest true density. The optimum drying time for the measurement of moisture content is 4 hours at the drying temperature of $100^{\circ}C$.

• Applied Chemistry for Engineering
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• v.10 no.6
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• pp.881-884
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• 1999

We have studied the other unit which is partial element in fullerene $C_{90}$. The energy of the higher fullerene increased by 5.6 kcal/mol for each $1.0{\beta}$ of planarity for the other units and increased by 11.0 kcal/mol for each $2C_1$ other unit at RHF/AM1 method. Therefore, we have known that the stable $C_{90}$ isomer do not have $C_1$ unit in other unit and have small planarity. The confirmable $C_{90}$ isomers by experiment satisfies these two conditions.

• Korean Journal of Computational Design and Engineering
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• v.12 no.3
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• pp.220-232
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• 2007

Current geometric modeling and analysis are commonly based on B-Rep modeling and a finite elements method respectively. Furthermore, it is difficult to represent an object whose material property is heterogeneous using the B-Rep method because the B-Rep is basically used for homogeneous models. In addition, meshes are required to analyze a property of a model when the finite elements method is applied. However, the process of generating meshes from B-Rep is cumbersome and sometimes difficult especially when the model is deformed as time goes by because the topology of deforming meshes are changed. To overcome those problems in modeling and analysis including homogeneous and heterogeneous materials, we suggest a unified modeling and analysis method based on implicit representation of the model using R-function which is suggested by Rvachev. For implicit modeling of an object a distance field is approximated and blended for a complex object. Using the implicit function mesh-free analysis is possible where meshes are not necessary. Generally mesh-free analysis requires heavy computational cost compared to a finite elements method. To improve the computing time of function evaluation, we utilize GPU programming. Finally, we give an example of a simple pipe design problem and show modeling and analysis process using our unified modeling and analysis method.

• The Mathematical Education
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• v.48 no.1
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• pp.1-20
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• 2009

The study was to investigate an effect of students' learning for enhancing spatial ability, using a geometric manipulative recently designed. A mixed methodology was chosen to achieve the purpose of the study. To find students' achievement, 152 of the 8th graders in Kyunggi Do participated in data collection. At the same time. students' performance of the class was videotaped and analyzed to see students' responses, The results showed that the effect of using the manipulative was statistically significant at level, p<.05 to enhance the spatial ability. Specifically, in comparison of each component. spatial orientation was more effective than spatial visualization. In the spatial orientation, the part of field was more effective than the reorganized whole. It showed that students were given more opportunities to find mathematical properties and relations between 2nd and 3rd-dimensional figures through their intuitive observation, and also the manipulative helped the students find the property of the part of field because it gave an easy way to manipulate the property of the find parts of whole which was composed of the frame of the solid figures without surfaces. In using the manipulative, students were very flexible in finding the number of plane figures, but the relations between the 2nd and 3rd dimensional figures need to be clearly guided in consideration of the characteristics of the manipulative, based on the definitions of geometric properties(cf. points can make lines, not surfaces directly).

• International Journal of Aeronautical and Space Sciences
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• v.18 no.2
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• pp.222-235
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• 2017

In this study, finite element modeling was used to predict the material properties of tri-axially braided textile composite. The model was made based on an experimental test specimen which was also used to compare the final results. The full interlacing of tows was geometrically modelled, from which repeating parts that make up the whole braid called unit cells were identified based on the geometric and mechanical property periodicity. In order to simulate the repeating nature of the unit cell, periodic boundary conditions were applied. For validation of the method, a reference model was analyzed for which a very good agreement was obtained. Material property calculation was done by simulating uniaxial and pure shear tests on the unit cell. The comparison of these results with that of experimental test results showed an excellent agreement. Finally, parametric study on the effect of number of plies, stacking type (symmetric/anti-symmetric) and stacking phase shift was conducted.

• Korean Journal of Computational Design and Engineering
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• v.8 no.4
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• pp.262-269
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• 2003

An approach to compute characteristic curves such as section curves, reflection characteristic lines, and asymptotic curves on a surface is introduced. Each problem is formulated as a surface-plane inter-section problem. A single-valued function that represents the characteristics of a problem constructs a property surface on parametric space. Using a contouring algorithm, the property surface is intersected with a horizontal plane. The solution of the intersection yields a series of points which are mapped into object space to become characteristic curves. The approach proposed in this paper eliminates the use of traditional searching methods or non-linear differential equation solvers. Since the contouring algorithm has been known to be very robust and rapid, most of the problems are solved efficiently in realtime for the purpose of visualization. This approach can be extended to any geometric problem, if used with an appropriate formulation.

• KIPS Transactions on Software and Data Engineering
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• v.8 no.10
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• pp.421-426
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• 2019

In this paper, we propose a method to visualize the geometric features of the contact region between proteins in a protein complex. When proteins or ligands are represented as curved surfaces with irregularities, the property that the two surfaces contact each other without intersections is called shape compatibility. Protein-Protein or Protein-Ligand docking researches have shown that shape complementarity, chemical properties, and entropy play an important role in finding contact regions. Usually, after finding a region with high shape complementarity, we can predict the contact region by using residual polarity and hydrophobicity of amino acids belonging to this region. In the research for predicting the contact region, it is necessary to investigate the geometrical features of the contact region in known protein complexes. For this purpose, it is essential to visualize the geometric features of the molecular surface. In this paper, we propose a method to find the contact region, and visualize the geometric features of it as normal vectors and mean curvatures of the protein complex.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.3
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• pp.451-457
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• 2009

Most of objects in computer graphics may be represented by a form of mesh. The exact computation of vertex normal vectors is essential for user to apply a variety of geometric operations to the mesh and get more realistic rendering results. Most of the previous algorithms used a weight which resembles a local geometric property of a vertex of a mesh such as the interior angle, the area, and so on. In this paper, we propose an efficient algorithm for computing the normal vector of a vertex in meshes. Our method uses the conformal mapping which resembles synthetically the local geometric properties, and the mean value coordinates which may smoothly represent a relationship with the adjacent vertices. It may be confirmed by experiment that the normal vector of our algorithm is more exact than that of the previous methods.