• 호남수학학술지
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• 제35권4호
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• pp.793-808
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• 2013

An interpolation-based unique decoding algorithm of Algebraic Geometry codes was recently introduced. The algorithm iteratively computes the sent message through a majority voting procedure using the Gr$\ddot{o}$bner bases of interpolation modules. We now combine the main idea of the Guruswami-Sudan list decoding with the algorithm, and thus obtain a hybrid unique decoding algorithm of plane AG codes, significantly improving the decoding speed.

• East Asian mathematical journal
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• 제30권2호
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• pp.197-222
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• 2014

The purpose of this research is to find out if it is possible to apply the Waldorf School's mathematics education method to Korean alternative schools which are run under the national curriculum. To achieve this, the researcher conducted class on geometry for three weeks with ten 7th graders(four girls and six boys) from Apple Tree Waldorf alternative school in Busan, which has adopted Valdorf education courses. For the first two weeks, the class was about 'fundamental geometrical construction', and then it was evaluated. On the third week, the lesson was on plane figures, followed by a test with 9 plane figure questions that are based on general middle school mathematics curriculum. The result shows that most of the students understood 'fundamental geometrical construction'. When it comes to the test on 'plane figures', seven students got 8 out of 9 right, two students got 6 out of 9 right, and one of them had difficulty solving the questions. According to the results of this research, it is thought that there will be no problem for students to understand mathematical concept even if the Waldorf School's mathematics education method is applied to Korean alternative schools. Also, the Waldorf School's mathematics education method is considered to be a good teaching model for the Korean mathematics curriculum which places emphasis on 'mathematical creativity' in regard to the curriculum and contents.

• 대한조선학회논문집
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• 제47권6호
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• pp.843-849
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• 2010

This paper presents definition of symmetry of a ship section where three symmetries are proposed: material, geometric, and load symmetries. Precise terminologies of centroid, moment plane, and neutral axis plane are also defined. It is suggested that force vector equilibrium as well as force equilibrium are necessary condition to determine new position of neutral axis due to translational and rotational mobility. It is also stated that new reference datum of ENMP(elastic neutral moment plane), PNMP(fully plastic moment plane), ENAP(elastic neutral axis plane), and INAP(inelastic neutral moment plane) are required to define asymmetric section properties such as second moment of area, elastic section modulus, yield moment, fully plastic moment, and ultimate moment. Since collision-induced damage and flooding-induced biaxial bending moment produce typical asymmetry of section, the section properties are calculated for a typical VLCC. Geometry asymmetry is determined from ABS and DNV rules and two moment planes of 0/30 degs are assumed for load asymmetry. It is proved that the property reduction ratios directly calculated from second moment of area are usually larger than area reduction ratio. Reduction ratio of ultimate moment capacity shows almost linearly proportional to area reduction ratio. Mobility of elastic and inelastic neutral axis planes is visually provided.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.1617-1622
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• 1991

Plane sweep is a general method in computational geometry. There are many efficient theoretical algorithms designed using plane sweep technique. However, their practical implementations are still suffering from the topological inconsistencies resulting from the numerical errors in geometric computations with finite-precision arithmetic. In this paper, we suggest new implementation techniques for the plane sweep algorithms to resolve the topological inconsistencies and construct the planar object boundaries from given input curve segments.

• 대한수학회지
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• 제36권6호
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• pp.1169-1180
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• 1999

Two-point comparison theorems between hyperbolic and euclidean geometry for convex regions in the complex plane are known([5], [6]). We give new geometric proofs of sharp two-point comparison theorems for convex regions.

• 한국패션뷰티학회지
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• 제4권1호
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• pp.28-34
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• 2006

The purpose of this study is to historically examine the thoughts and ideas of geometry and to analyze the expression style of design applied to the mass communication such as magazines and world wide webs, by giving definitions on the ideas of geometry and the pattern of cognition. Geometry was evolved to Descartes's analytical geometry, projective geometry, non-Euclidean geometry and Topology at the end of 19th century. When geometry applies to design styles, it is devided into two field, plane geometry and solid geometry. The development of geometry was completed from the Pythagoras symbolic theory of number to Platonic spiritual geometry and Euclidean geometry. It can be studied that those have what kind of symbolic meanings and transformations on each hair design plan. It can also analized how those symbolic forms are appeared on the design form. This tendency means that there is always a try for the use of geometry as reasonable device for hair design. If the hair design and geometry have logical and artistical relation, we can make buildings which have a order, balance and harmony.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1778-1782
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• 2007

Based on three-dimensional (3-D) FE limit analyses, this paper estimates effect of internal pressure on plastic limit loads for elbows with circumferential through-wall crack under in-plane bending incorporating large geometry change effects. Circumferential through-wall crack in extrados is considered. The FE limit analyses using the large geometry change option provide plastic collapse loads (using the twice-elastic-slope method). For the bending mode, closing bending is considered. Other relevant variables affecting plastic limit loads are systematically varied, related to pipe bend geometry (the mean radius, thickness and bend curvature) and defect geometry (the length of circumferential through-wall crack).

• 한국수학사학회지
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• 제15권2호
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• pp.15-32
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• 2002

The first part of this thesis gives some brief explanation of the theory and history of imaginary elements in analytic geometry in the 19th century. The second part of this thesis discusses the theory of imaginary elements of synthetic geometry in the first half of the 19th century. Then the next part mentions the theory of imaginary elements of geometry in the second half of that same century. Particularly Christian von Staudt's and Felix Klein's theories are handled in this part. Von Staudt, who has completed the system of the synthetic projective geometry, used ‘involution’ in order to introduce a new concept ‘imaginary elements’- imaginary points, imaginary lines and imaginary plane-in synthetic geometry. Klein applied von Staudt's theory as he convey the result of the research in algebraic geometry in a picture. Von Staudt's and Klein's research may be regarded as the top of the effort to investigate possible relationship between real and imaginary structures.

• 대한조선학회논문집
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• 제40권1호
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• pp.28-35
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• 2003

Fatigue tests of transverse fillet weldment were performed under out-of-plane bending loads. Significant increase of the fatigue strength was observed under out-of-plane bending loads, compared to the one under in-plane loads (axial loads). Applicability of the crack propagation analysis using LEFM for the surface crack of fillet weldment were investigated as well, in parallel with the fatigue tests. For the rational assessment of the fatigue strength of welded ship structures where combined stresses of the in-plane axial stress and the out-of-plane bending stress are induced simultaneously due to complexity of applied load and structural geometry, further investigation is recommended for the effect of the out-of-plane bending stress on the fatigue strength of weldment.

• 호남수학학술지
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• 제34권1호
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• pp.103-111
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• 2012

Wetzel[5] proved if ${\Gamma}$ is a closed curve of length L in $E^n$, then ${\Gamma}$ lies in some ball of radius [L/4]. In this paper, we generalize Wetzel's result to the non-Euclidean plane with much stronger version. That is to develop a lower bound of length of a triangle inscribed in a circle in non-Euclidean plane in terms of a chord of the circle.