• Computational Structural Engineering
• /
• v.10 no.1
• /
• pp.135-148
• /
• 1997

The main objective of this paper is to analyze the rectangular stiffened plates with two opposite ends elastically restrained and the others simply supported subjected to in-plane bending by Finite Element Method. Another objective is to develope Classical Method analyzing the unstiffened rectangular plates with the above boundary conditions. In order to validate finite element and classical methods, the buckling strengths of the rectangular plates with four simply supported ends, and with two simply supported and the others fixed ends by finite element method and classical method are compared with those of references. In finite element method, elastically restrained ends can be obtained as considering torsional and warping rigidities of end stiffeners. The buckling strengths of the rectangular plates with elastically restrained ends by finite element and classical methods are calculated and compared with each other. In case of stiffened plates, to validate finite element method, the buckling strengths of the rectangular stiffened plates with four simply supported ends, and with two simply supported and the others fixed ends are also compared with those of references. The buckling strengths of the rectangular stiffened plates with elastically restrained ends by finite element method are calculated as solving eigenvalue problems which are obtained as assembling rectangular plate elements and beam elements considered torsional and warping rigidities. The buckling strengths of rectangular stiffened plates according to various positions of rectangular intermediate stiffener, J and I/sub w/ of end stiffeners are also obtained, which are compared to determine the efficient position of intermediate stiffener.

• Journal of Elementary Mathematics Education in Korea
• /
• v.18 no.3
• /
• pp.441-457
• /
• 2014

This study starts with the idea that Korean mathematical word 'byon' which means 'side' of polygons or angles is very ambiguous. The purpose of this study is to make the concept and range of 'byon' clear and to suggest the ideas which can help children understand the concept of 'byon'. For this, various dictionary and the past Korean mathematics curriculums are reviewed. As a result, two attributes 'byon' has are identified and some reasons which block children from understanding 'byon' are detected in its introduction method of mathematics text books and inkhorn of the mathematical term. Finally, two different ideas for helping children understand the concept 'byon' are suggested based on the conclusion of this research.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.37 no.4
• /
• pp.491-496
• /
• 2013

Finite element simulations of tensile tests were performed to determine the equivalent stress - equivalent plastic strain curves, critical equivalent stresses, and critical equivalent plastic strains. Then, the curves were used as inputs to finite element simulations of fracture toughness tests to determine the plane strain fracture toughness. The critical COD was taken as the COD when the equivalent plastic strain at the crack tip reached a critical value, and it was used as a crack growth criterion. The relationship between the critical COD and the critical equivalent plastic strain or the reduction of area was found. The relationship between the plane strain fracture toughness and the product of the critical equivalent stress and the critical equivalent plastic strain was also found.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2007.05a
• /
• pp.398-402
• /
• 2007

본 연구에서는 삼각 요소망을 구성하는데 사용되는 기존의 Delaunay Triangulation 기법 외에 Advanced Front Technique 알고리즘을 적용하여 하천의 경계가 중요시되는 해석 모델에 적합한 삼각 요소망을 생성하고자 한다. Advanced Front Technique 알고리즘은 외부 경계를 따라 삼각 요소를 형성하기 시작하여 전체 해석 영역으로 요소를 채워가는 방법이다. 이 방법은 위에서 언급한 Delaunay Triangulation 기법의 단점인 해석 영역의 경계에서 요소의 형질이 좋지 못한 문제를 극복할 수 있을 뿐만 아니라, 미리 절점을 생성하지 않으므로 메모리를 절약하는 효과도 얻게 된다. Advanced Front Technique 알고리즘은 외부 경계의 노드(i)와 노드(i+1)을 Front로 하고, 이등변삼각형을 이루기 위해 해석 영역 내부의 적절한 위치에 새로운 절점(C)을 생성한다. 이렇게 Front와 새로운 절점(C)으로 이루어진 이등변 삼각형 요소가 생성된 후에, Front는 다음 Front로 전진하면서 점차 해석 영역의 내부로 삼각형 요소를 채우게 된다. 이와 같은 방법에 의해서 해석영역의 경계에서는 비교적 이등변 삼각형에 가까운 삼각 요소가 생성된다.

• Journal of Science Education
• /
• v.33 no.2
• /
• pp.271-289
• /
• 2009

The purpose of the research was to analyze the characteristics and the process elements which appeared to the process of designing experiment for biologists and gifted students in science. Four biologists and thirty-two gifted students were participated in this study. The findings indicated that (a) the researcher figured out the process elements could constructed in fifteen elements such as confirming questions, arrange materials, consideration for experimental subjects, searching variables, eliminating variables, selecting variables, planning operation of variables, planning control environmental variables, planning control biological variables, planning the methods of observation and assessment, planning the methods of collecting data, planning the interpretation of data, planning the repetition of experiments, planning the repetition of assessment, safety regulations as well. The biologists concentrated in the particular process elements related with variables, since the science-gifted students concerned the performance whole process elements themselves without deeper consideration, (b) the characteristics of biologists and science-gifted students in the process of designing experiment were as follows; 1) biologists and students showed the process elements which include the domain specific process skills as well, 2) biologists accurately conducted the designing experiments processes with repetition of specific process, since students designed experiments conventionally, and 3) biologists possessed the domain specific skills and know-how about their experiments, but students did not. The results show that the programs of designing experiment activity should be constructed with the process elements which were concentrated by biologists, should provide feedbacks to design experiment more accurately, and should be developed with concern of the process skills and know-hows of biologists.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.14 no.1
• /
• pp.71-81
• /
• 1994

A method is presented for the analysis of curved segmentally erected prestressed concrete box girder bridges including time-dependent effects due to load history, temperature history, creep, shrinkage, aging of concrete and relaxation of prestressing steel. The segments can be either precast or cast-in-place. Thin-walled beam theory and finite element method are combined to develop a curved nonprismatic thin-walled box beam element. The element consists of three nodes and each node has eight displacement degrees of freedom, including transverse distortion and longitudinal warping of the cross section.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.2A
• /
• pp.391-399
• /
• 2006

Plate girders with variable depths have been often used at piers considering not only the economy but also an aesthetic aspect. Tapered plate girders exhibit more complicated behaviors than prismatic girders especially under shear. However, a comprehensive design method for the determination of the shear strength has yet to be developed mainly due to lack of study. In this study, investigated is the buckling and ultimate behaviors of tapered plate girders subjected to shear through finite element analyses. From the analysis results, a simple design formula is suggested for the evaluation of the shear strength of tapered plate girders.

• Journal of Korean Society of Transportation
• /
• v.19 no.6
• /
• pp.255-256
• /
• 2001

• Journal of KIISE
• /
• v.43 no.9
• /
• pp.974-982
• /
• 2016

Mutation analysis (or software mutation analysis) generates variants of a target program by injecting systematic code changes to the target program, and utilizes the variants to analyze the target program behaviors. Effective mutation analyses require adequate mutation operators that generate diverse variants for use in the analysis. However, the current mutation analysis tools for Java programs have limitations, since they support only limited types of mutation operators and do not support recent language features such as Java8. In this study, we present Mutagen4J, a new mutant generation tool for Java programs. Mutagen4J additionally supports mutation operators recently shown to generate various mutants and fully supports recent Java language features. The experimental results show that Mutagen4J generates useful mutants for analyses 2.3 times more than the existing Java mutation tools used for the study.

• Korean Architects
• /
• no.3 s.347
• /
• pp.72-76
• /
• 1998

본 특집은 지방시대에 지역건축문화가 어떻게 변화하고 정착되고 있는가? 그 지역만의 갖고 있는 도시+건축문화의 아이덴티티는 무엇이고, 현대화과정에서 그 지역의 고유한 문화경관요소가 개발과 보존이라는 병립된 사회요구속에서 어떻게 적응되고 있는가에 대해 살펴봄을 의도하고 있다. 특히 백제문화권의 중심도시인 아산, 부여, 공주의 도시특성을 이루고 있는 도시공간구조 및 구성요소와 그 속에 내포되어 있는 문화경관요소의 현황을 살펴본다. 본고는 현대화하는 과정 속에서 전통성이 있는 문화요소를 지역성의 개념과 상관적으로 관련시켜 정리하기 위한 것이다. 문화가 지역을 초월하여 국제적으로 교류되면서, 생활의 편익성을 추구하는 현대인들은 국가와 민족의 차이를 넘어 동일한 지구문화형성의 과정으로 급속히 진행하고 있다. 현대화는 서구화라는 등식은 서구문화의 간결한 편익성이 낳은 전세계적 현상이다. 따라서 현대화를 생활의 변화로 이해할 때에 전통논의의 여유가 있고, 전통논의에 대한 객관성이 있으며, 편협된 전통관으로부터 자유로와질 수 있다. 시간의 변화에 따라서 생활이 변하고, 특히 생활을 담는 그룻으로서 건축환경이 변한다. 오랜 시간을 통해서 서서히 건축환경이 변하지만, 누적된 변화는 커다란 차이로서 나타나고, 이에 따라 적응과정에서의 여러 문제점이 발생한다. 그러므로 현재까지 많이 논의되어온 보전과 보존의 방법론적 세분화에 의한 적극적인 대책이 요구되는 시점에 있다고 할 수 있다. 해서 '전통성을 갖춘' 도시ㆍ건축구조물을 단순한 유적, 유물로 보존할 것인가, 실생활과 관련된 생활과 함께 하는 문화현상으로 적응시킬 것인가 하는 문제점이 우리의 과제인 것이다.