• 한국수학교육학회지시리즈C:초등수학교육
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• 제2권1호
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• pp.65-73
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• 1998

The purpose of this study is to investigate significant differences of structural knowledges among the groups(high, middle, low) when the 6th grade subjects structured the concepts of the plane figures, triangle and quadrangle, by concept maps, and to analyse the features of concept maps according to hierarchy. For this purpose, the following two research contents were investigated： 1. Investigating significant differences of structural knowledge in the concepts of the plane figures using concept maps among the groups(high, middle, low). 2. Analysing the features of concept maps according to hierarchy. The structural knowledges represented on the concept maps of triangle and quadrangle which were drawn by the subjects were analysed by propositions, hierarchies, and cross-links. Subject-self Reports about how to make the concept maps were used to analyse the features of concept maps according to hierarchy. The conclusions drawn from the results were as fellows： First, there were significant differences among the groups in proposition links. Second, there wasn't my significant difference among the groups in hierarchy. Third, there were significant differences among the groups in cross-links, and Fourth, the results of analysing the concept maps by hierarchy showed that there were differences among the individuals in constructing the knowledges.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 춘계학술발표대회 논문집
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• pp.75-78
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• 2004

Traditionally aluminum alloy have been used in manufacturing of aircraft structures, and semi-monocoque structural concept have been mainly applied in structural design of fuselage and wing. However, recently monocoque structural concept is applied in many small-size aircraft structures manufactured with composite materials. In such case appling monocoque structural concept, in initial conceptual design stage on wing, it is not easy to analyze shear flow using classical shear flow analytical method because composite skin structure can support span-wise tension/compression stress as well as sectional shear stress. In this study, an extended shear-flow analytical method to apply to composite monocoque structural concept was developed through extending the classical shear-flow analytical method.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 봄 학술발표회 논문집
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• pp.102-109
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• 2001

In order to take account of the statistical properties of probability variables used in the structural analysis, the conventional approach using the safety factor based on past experience usually estimated the safety of a structure. The real structures could only be analyzed with the error in estimation of loads, material characters and the dimensions of the members. But the errors should be considered systematically in the structural analysis. Structural safety could not precisely be appraised by the traditional structural design concept. Recently, new approach based on the probability concept has been applied to the assessment of structural safety using the reliability concept. Thus, the computer program by the Probabilistic FEM is developed by incorporating the probabilistic concept into the conventional FEM method. This paper estimated for the reliability of a plane stress structure by Advanced First-Order Second Moment method using von Mises, Tresca and Mohr-Coulomb failure criterions. The reliability index and failure probability of attained by the Monte Carlo Simulation method with the von Mises criterion were same as PFEM, but the Monte Carlo Simulation were very time-consuming. The variance of member thickness and load could influence the reliability and failure probability most sensitively among the design variables from the results of the parameter analysis. And proper failure criterion must be used to design safely.

• 대한수학교육학회지:수학교육학연구
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• 제26권1호
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• pp.23-45
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• 2016

우리가 어떤 한 개념을 형성하면 우리는 그 개념을 이용하여 어떤 사회 현상 또는 자연현상을 분석할 수 있는 힘을 갖게 된다. 그러나 어떤 대상에 대한 한 개념을 형성하는 것은 쉬운 일이 아니다. 한 개인이 어떤 개념이든 그 개념을 이해하는 과정은 실로 험난한 정신적 여정이다. 이런 이유로 개념의 이해에 관한 문제는 교육에서 늘 연구의 대상이 되어왔다. 우리는 개념에 대한 선행연구를 통해 개념이 이중적 본성 즉, 조작적 특성과 구조적 특성을 갖고 있음을 알게 되었다. 또한 한 개념은 조작적 개념에서 구조적 개념으로 발전한다는 것을 이전 연구에서 발견할 수 있다. 그러나 어떤 한 개념의 이중적 본성을 안다는 것은 매우 어려운 일이며 특히 학생들이 한 개념의 구조적 개념을 이해하였는지 알기는 더더욱 쉽지 않다. 이에 본 연구에서는 질량중심의 개념에 대한 조작적 특성과 구조적 특성을 알아보고, 학생들이 질량중심 개념에 대하여 그 개념을 조작적 접근을 통하여 구조적 개념으로 어느 정도 형성하게 되는지 검사와 면담을 통하여 분석하고자 한다. 또한 이러한 분석을 통하여 한 개념에 대한 구조적 개념을 형성하도록 하기 위해서 무엇을 해야 하는지 그 함의하는 바를 찾고자한다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 가을 학술발표회 논문집
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• pp.425-431
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• 2001

In order to take account of the statistical properties of probability variables used in the structural analysis, the conventional approach using the safety factor based on past experience usually estimated the safety of a structure. The real structures could only be analyzed with the error in estimation of loads, material characters and the dimensions of the members. But the errors should be considered systematically in the structural analysis. Structural safety could not precisely be appraised by the traditional structural design concept. Recently, new approach based on the probability concept has been applied to the assessment of structural safety using the reliability concept. In this study, safety of structures will estimated by the reliability analysis with commercial structural software that has the tools of nonlinear elastic-plastic 3-D analysis. Experimental test result is compared to results from this research and Coan/sup 1)/ In this paper, AFOSM(Advanced First-Order Second Moment method) is applied with von Mises, Tresca and Mohr-Coulomb failure criterions. The reliability index β and probability of failure P/sub f/ can be obtained by following this practical procedure as judgement a safety of structures and necessity of reinforcing.

• Smart Structures and Systems
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• 제5권2호
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• pp.173-191
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• 2009

Civil infrastructures are always subjected to various types of hazard and deterioration. These conditions require systematic efforts to assess the exposure and vulnerability of infrastructure, as well as producing strategic countermeasures to reduce the risks. This paper describes the needs for and concept of advanced sensor technologies for risk assessment of civil infrastructure in Japan. Backgrounds of the infrastructure problems such as natural disasters, difficult environment, limited resource for maintenance, and increasing requirement for safety are discussed. The paper presents a concept of risk assessment, which is defined as a combination of hazard and structural vulnerability assessment. An overview of current practices and research activities toward implementing the concept is presented. This includes implementation of structural health monitoring (SHM) systems for environment and natural disaster prevention, improvement of stock management, and prevention of structural failure.

• 대한가정학회지
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• 제46권9호
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• pp.113-123
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• 2008

The purpose of this study was to investigate how parenting and peer relationships influence the development of adolescent self-concept by using Structural Equation Modeling(SEM). The subjects were 198 first graders (94 male and 104 female) from four high schools within the Seoul area. Descriptive and comparative statistical analysis was conducted with SPSS (Version10.0), while AMOS (Version 4.0) was used to assess structural equation modelling of parenting, peer relationship and the self-concept. Results showed that, in terms of correlation, more positive parenting behaviors induced more positive self-concept. In addition, better peer relationships demonstrated more positive self-concept. Regression analysis showed that peer relationships explained the variance in adolescents' self-concept more effectively than parenting behavior. This was confirmed by the SEM.

• 한국지진공학회논문집
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• 제2권3호
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• pp.73-81
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• 1998

In this paper, the necessity of developing effective nondestructive testing and monitoring techniques for the evaluation of structural integrity and performance is described. The evaluation of structural integrity and performance is especially important when the structures and subject to abrupt external forces such as earthquake. A prompt and extensive inspection is required over a large area of earthquake-damaged zone. This evaluation process is regarded as a part of performance-based design. In the paper, nondestructive testing and monitoring techniques particularly for concrete structures are presented as methods for the evaluation of structural integrity and performance. The concept of performance-based design is first defined in the paper followed by the role of evaluation of structures in the context of overall performance=based design concept. Among possible techniques for the evaluation, nondestructive testing methods for concrete structures using radar and a concept of using fiber sensor for continuous monitoring of structures are presented.

• Structural Engineering and Mechanics
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• 제3권5호
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• pp.475-495
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• 1995

In the past, physical models have been proposed, in compliance with the concept of the compressive-force path, for the realistic design of various statically determinate structural concrete members. The present work extends these models so as to encompass indeterminate RC structural forms. Pilot tests conducted on continuous beams and fixed-ended portal frames have revealed that designing such members to present-day concepts may lead to brittle types of failure. On the other hand, similar members designed on the basis of the proposed physical models attained very ductile failures. It appears that, unlike current design approaches, the compressive-force path concept is capable of identifying those areas where failure is most likely to be triggered, and ensures better load redistribution, thus improving ductility. The beneficial effect of proper detailing at the point of contraflexure in an indeterminate RC member is to be noted.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1996년도 추계학술대회 학술발표 논문집
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• pp.186-193
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• 1996

This paper presents a fuzzy structural modeling using the concept of Saaty's pairwise comparison matrix. The merit of this approach can be reduced the number of pairwise comparison.