• Proceedings of the Korean Society of Laser Processing Conference
• /
• 2001.05a
• /
• pp.86-91
• /
• 2001

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• v.12 no.1
• /
• pp.7-11
• /
• 2008

The energy of a graph is the sum of the absolute values of its eigen values. We obtain some bounds for the energy of planar graphs in terms of its vertices, edges and faces.

• Proceedings of the Korean Ceranic Society Conference
• /
• 2003.10a
• /
• pp.63.1-63
• /
• 2003

• The Bulletin of The Korean Astronomical Society
• /
• v.31 no.2
• /
• pp.70.2-70.2
• /
• 2006

• Journal of Korea Foundry Society
• /
• v.9 no.6
• /
• pp.446-453
• /
• 1989

무철심 유도로를 이용한 주철 및 주강의 용해보온에 요구되는 야금학적인 조건에 관하여 광범한 연구 조사가 있었다. 가장 중요한 법칙을 요약 설명하고자 한다. 이들 법칙은 주물공장에서 활용할 수 있으며 주물의 모서리 근처, 가혹한 조건하에서 발생 할 수 있는 여러 가지 결함을 방지하는데 도움이 될 것이다. 이러한 점에서 작업공정 절차를 관찰하는 것이 중요하며 현장에서 사용하도록 판정도표를 작성하였다.

• Journal for History of Mathematics
• /
• v.15 no.2
• /
• pp.33-48
• /
• 2002

In this article we study various proofs of Euler's theorem(the number of faces of any polyhedron, together with the number of vertices, is two more than the number of edges), from these proofs extract some mathematical ideas. In this paper we in detail introduce eight different proofs from various articles and textbooks.

• Korean Journal of Cognitive Science
• /
• v.17 no.3
• /
• pp.151-175
• /
• 2006

A common constraint-range model was suggested to explain the extraction of edge orientation from kinetic occlusion and five experiments were performed to verify this model. Results of the experiments show that the subjects' ability to identify the orientation of the kinetic edge increases as the angle of common constraint-range decreases. If the common constraint-range was fixed, the number of occluded elements or the interval between them had no effect on the accuracy. These results indicate that in the edge extraction process from kinetic occlusion, the angle of common constraint-range plays more important role than the density of background texture, supporting the common constraint-range model.

• The Transactions of the Korea Information Processing Society
• /
• v.4 no.4
• /
• pp.1121-1131
• /
• 1997

In video coding at high compression rate, factal compression schemes in spatial domain have outstanding blocking artifacts and compression schemes in wavelet transform domain have rinfing artifacts at edges. In order to compensate these disadvantages, we propose a fractal video coding in wavelet transrorm domain which leads to clear edges without blocking atrifacts even at high bompression rate. The proposed method performs variable block sized motion estimation by using correlation among different subbands. Then the wavelet coefficients which are not enoded dffectively by the motion estimation are compressed by inter-frame fractal coding which predicts fine scale subbands hierarchically from the next coarser scale subbands. Computer sumulations with sev-eral test images wequences show that the proposed method shows better performance than the conventional video coding methods using fractal and wavelet.

• Journal of the Korean Society of Industry Convergence
• /
• v.5 no.1
• /
• pp.45-52
• /
• 2002

In this study, an exact solution of governing differential equation for the bending problem of partially loaded orthotropic rectangular plates is presented and also its computer program is developed. The method requires that two opposite edges be clamped or simply supported, or one edge clamped and the other simply supported. Any combination of boundary conditions could exist along the other edges. The plate could he subjected to uniform, partially uniform, and line loads. The solution for the deflection of rectangular plate is expressed as a Levy type single Fourier series and the loads arc expressed as a corresponding series. The advantage of the solution is that it overcomes the limitations of the previous Navier's and Levy's methods (limitation of boundary condition and loading conditions of plate), it is easy to program on a computer and it becomes fast to solve the bending problem with computer program. Calculations are presented for isotropic and orthotropic plates with different loading and boundary conditions. Comparisons are made for the isotropic plate with various boundary conditions between the result of this paper and the result of Navier, Levy and Szilard. The deflections were in excellent agreement.

• The Bulletin of The Korean Astronomical Society
• /
• v.40 no.1
• /
• pp.63.1-63.1
• /
• 2015

In this study, we determine coronal electron density distributions by analyzing DH type II radio observations based on the assumption: a DH type II radio burst is generated by the shock formed at a CME leading edge. For this, we consider 11 Wind/WAVES DH type II radio bursts (from 2000 to 2003 and from 2010 to 2012) associated with SOHO/LASCO limb CMEs using the following criteria: (1) the fundamental and second harmonic emission lanes are well identified; (2) its associated CME is clearly identified in the LASCO-C2 or C3 field of view at the time of type II observation. For these events, we determine the lowest frequencies of their fundamental emission lanes and the heights of their leading edges. Coronal electron density distributions are obtained by minimizing the root mean square error between the observed heights of CME leading edges and the heights of DH type II radio bursts from assumed electron density distributions. We find that the estimated coronal electron density distribution ranges from 2.5 to 10.2-fold Saito's coronal electron density models.