• Journal of the Computational Structural Engineering Institute of Korea
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• v.12 no.1
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• pp.1-14
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• 1999

선형탄성이론을 기초로 한 구조해석의 경우 사용하중상태에서의 변형과 응력은 만족할 만한 결과를 나타내지만, 항복후의 처짐과 파괴시의 극한하중 산정의 정확한 해석이 불가능하다. 평판의 극한해석시, 상한계 이론을 바탕으로 한 항복선 이론이 널리 사용되고 있으나 이론적으로 평판의 강도를 과대평가하게 된다. 그러므로, 임의의 하중조건과 경계조건에 대한 비선형 거동과 극한내하력을 산정할 수 있는 해석기법이 필요하다. 평판의 정확한 극한하중을 위해 p-Version 유한요소법을 제안하며, p-Version의 해석치를 범용 구조해석 프로그램인 ADINA의 결과와 문헌의 이론치와 비교하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.1A
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• pp.39-48
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• 2012

This study deals with numerical determination of stress intensity factors of adhesively patch-repaired plates with cracks at V-shaped or semicircular notches. The p-convergent anisoparametric model are considered and then three-dimensional virtual crack closure technique is presented using formulations of anisoparametric elements. In assumed displacement fields of an element, strain-displacement relations and three-dimensional constitutive equations are derived with three-dimensional hierarchical shape functions expanded from one-dimensional Lobatto functions. Transfinite mapping technique is used to represent a circular boundary. The present model provides accuracy and simplicity in terms of stress concentration factor, stress distribution, the number of degrees of freedom, and non-dimensional stress intensity factor as compared with previous works in literatures. Stress intensity factors obtained by the three-dimensional virtual crack closure technique are estimated with respect to the variation of width of finite plate, radius of notch root, angular inclination of V-shaped notch, and crack length.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.10 no.4
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• pp.43-52
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• 1990

Theoretical foundation and algorithms are presented of a new surface modeling and pre-processing system for the three-dimensional structures. The modeling method is based on the boundary representation scheme and composed of two hierarchical model structures: curve-network and surface models. The concept of modeling curve as a union of links is introduced to facilitate surface modeling via various transfinite mapping techniques or Coons Patches. Efficiency and novel aspects of the present method are discussed. Finite element mesh genceration and application procedures will be reported in a later paper.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.5
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• pp.463-474
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• 2009

Double symmetric patch repair of existing structures always causes membrane action only, however, in many cases this technique is not practical. On the other hand, the bending stiffness of the patch and the skin increases as tensile loading is increased and affects the bending deformation significantly in the case of single-sided patch repair. In this study, the p-convergent full layerwise model has been proposed to determine the stress concentration factor in the vicinity of a circular hole as well as across the thickness of plates with single-sided patch repair. In assumed displacement field, the strain-displacement relations and 3-D constitutive equations of a layer are obtained by the combination of 2-D and 3-D hierarchical shape functions. The transfinite mapping technique has been used to represent a circular boundary and Gauss-Lobatto numerical integration is implemented in order to directly obtain stresses occurred at the nodal points of each layer without other extrapolation techniques. The accuracy and simplicity of the present model are verified with comparison of the previous results in literatures using experiment and conventional 3-D finite element. Also, the bending effect has been investigated with various patch types like square, circular and annular shape.

• Journal of the Korea Computer Graphics Society
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• v.22 no.2
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• pp.1-10
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• 2016

The computational cost of clothing simulation and rendering is mainly depends on the type of mesh and its quality. Thus, quadrilateral meshes are generally preferred over triangular meshes for the reasons of accuracy and efficiency. This paper presents a method of quadrangulating sewing pattern based on the recursive geometry decomposition method. Herein, we proposed two simple improvements to the previous algorithms. The first one deals with the recursive geometry decomposition in which the physical domain is decomposed into simple and mappable regions. The second proposed algorithm deals with the vertex validation in which the invalid vertex classification can be validated.

• KOREAN POULTRY JOURNAL
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• v.36 no.9 s.419
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• pp.108-111
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• 2004

10년만에 찾아온 지난 여름 무더위는 양계인들에게 큰 어려움을 안겨주었다. 단열과 환기를 완벽하게 한 농장이라도 외부에서 들어오는 바람 자체의 온기로 계사 내부의 온도를 낮추는데는 한계가 있었다는 반응들이다. 혹서로 인해 전국적으로 $20\%$정도의 생산성이 감소하면서 난가도 8월 25일 현재 129원(서울경기발표기준)이라는 사상 초유의 가격이 형성되면서 계란을 구하기에 급급한 유통상인들의 움직임을 감지할 수 있었다. 그러나 금년 3차례에 걸친 사료가격 인상과 더위로 인한 산란율 저하, 폐사 등으로 실질적인 농가소득은 그리 크지 않은 것으로 나타나고 있다. 문제는 이 같은 가격이 언제까지 유지되어줄 것인지, 고병원성가금인플루엔자 등 질병이 언제 농장에 급습할지 등에 항상 불안한 마음으로 양계를 해야하는 것이 현 실정인 것이다. 따라서 본고는 어려운 주변 여건에도 불구하고 양계업을 천직으로 알고 채란업을 묵묵히 경영하고 있는 배로농장(대표 나상화, 52)을 찾아 고품질의 계란생산 방법 등 농장경영 현황을 들어보았다.

• Journal of the Korean Society for Precision Engineering
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• v.4 no.1
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• pp.9-20
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• 1987

지난해 우리나라는 주요 10대업종중 <조선>과 <건설>을 제외하고 대부분의 업종이 3저의 영향으로 생산, 내수, 수출등 제분야에서 고루 균형을 가진 호황의 한 해였다. 우리나라는 본원적으로 부존자원이 없는데다가 외채자본에 의존한 결과, 경제적 자립성을 유지하기 위해서는 부득이 해외시장에 의존하지 않을 수 없다. 그러기 때문에 정부는 지 금까지 수출주도형 고도성장정책을 견지해 왔으며 이 결과 국제수지의 적자와 물가상승등 부작용이 뒤따른것도 사실이다. 아뭏든 지난해의 우리나라 경제를 요약하면 경제성장- 물가안정-국제수지흑자로 이어졌는데 결국 세마리의 토끼를 한꺼번에 잡은 행운의 한 해 였음이 분명하다. 특히 값진 보람이라고 한다면 지금까지의 만성적인 국제수지적자가 추 방되고 사상초유의 흑자원년을 기록했다는 사실이다. 이렇게 볼 때, 우리기업인들은 행운이였다고 하기 이전에 주어진 기회를 재빠르게 포착하여 이용했다는 사실에서 그 저력을 과시하는 표현이 더욱 적절할 것 같다. 금년에도 또 몇마리의 토끼를 잡기 위해서는 고속성장보다는 안정된 기조하에서 수출주도형의 경제정책이 계속 밀고나가야할 것으로 생각 된다. 3저현상은 무한히 지속하는 것이 아니며 언제 무산될지 모르는 미래에 대비하여 사전 에 그 대응책이 마련되어야 하며 이 처방은 경쟁 우위력에서 구해내야할 것이다. 따라서 우리 는 축적된 경험과 <노우하우>를 바탕으로 품질의 고급화, 생산성향상, 부가가치의 증진등으로 선진국 대열에 진입할 수 있는 힘을 키워야 하며 이것은 오직 노사협조라는 평범한 진리에서 얻을 수 있다. 금년도 년초에 대통령의 국정연설에서 <올해는 우수한 기술. 기능인이 대폭 육성되고 이들이 산업현장에서 자기의 꿈을 키울 수 있도록 더욱 효과있는 지원제도를 발전해 나갈 것이다...>라고 하였고 또 <이같은 과학기술의 진흥과 산업현장의 기술. 기능인력을 양 성하는 데 역점을 둔다...>는 최고지도자의 구상은 바로 우리가 기대했던 공감대를 형성하였 다고 본다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.4_1
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• pp.1-8
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• 1992

This paper presents a p-version finite element approach for modeling the stress distribution around a circular hole in a finite strip subjected to membrane and flexural behaviors. Also, same problem with a crack emanating from a perforated tension strip was solved by virtual crack extension method. The p-version of the finite element method based on integrals of Legendre polynomials is shown to perform very well for modeling geometries with very steep stress gradients in the vicinity of a circular cutout. Here, the transfinite mapping technique for circular boundaries was used to avoid the discretization errors. The numerical results from the proposed scheme have a good comparison with those by Nisida, Howland, Newman etc. and the conventional finite element approach.

• Journal of Korean Home Economics Education Association
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• v.16 no.3
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• pp.131-146
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• 2004

The Purpose of this study is to suggest strategies for environmental education through the Practical Arts(TechnologyㆍHome economics) Subject in a viewpoint of the clothing & textiles resources to resolve problems in the clothing life area. For this, this study was carried out through review of literature which is related with the consumption, the environmental problems, the environmental policies, and regulations of the government and new environmental technologies, of clothing & textiles industries and environmental education. The major findings of the study were as follows; 1) The environmental education system model in a viewpoint of the Clothing & Textiles resources was developed. This model system is consisted with interactions on school, government, industry, home and non-government organizations. Thus, the fact that Practical Arts(TechnologyㆍHome economics) Subject were the most effective subject to teaching the environmental education viewpoint of the Clothing & Textiles resources was confirmed. 2) The standards were analysed out to analyse the contents in the clothing area of the Practical Arts(TechnologyㆍHome economics) Subject. It were consist of 4 factors and 12 elements under the factors: Awareness of clothing & textile resources(clothing consumption, production of clothing & textile and environmental problems). Planning and buying of clothing(planning, buying), Management of clothing(understand of textile. human body & environment, laundering and Environmental pollution, arrangement & conservation) Recycling & exhaust of clothing(contribution, redesign, recycling, exhaust) 3) Analysing the current Practical Arts (TechnologyㆍHome economics) subject from the Environmental education in the clothing section, the environmental education related with clothing were taught the most in the middle school course, and environmental contents were concentrated in the recycling factors. but not so much on other factors. 4) After analysing the Practical Arts (TechnologyㆍHome economics) subject, the strategies were suggested for reinforcing the environmental education in the clothing of the Practical Arts(TechnologyㆍHome economics) subject.