• Title/Summary/Keyword: structural concept

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An Analysis on Structural Knowledges by Concept Maps -Focused on Plane Figures in Elementary School- (개념도를 이용한 구조적 지식의 조사 연구 -초등학교 평면 도형 단원을 중심으로-)

  • 정승진;박배훈
    • Education of Primary School Mathematics
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    • v.2 no.1
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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.

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Shear Flow Analysis of Aircraft Composite Wing Structure (항공기 복합재 날개구조 전단흐름 해석)

  • Choi Ik-Hyeon;Kim Seong-Chan;Kim Seong-Jun
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2004.04a
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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.

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A Design Variable Study of Plane Stress Element by Reliability Analysis (신뢰성 해석에 의한 평면응력요소의 설계변수 분석)

  • 박석재;최외호;김요숙;신영수
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2001.04a
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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.

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A Study on the Structural Conception Formation of the Center of Mass Concept (질량중심 개념의 구조적 개념 형성에 관한 연구)

  • Choi, Byung Chul
    • Journal of Educational Research in Mathematics
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    • v.26 no.1
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    • pp.23-45
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    • 2016
  • We are able to analyze a social or a natural phenomenon by using the conception. if we understand a concept of an object. However it is not easy to understand a concept of an object. The process of comprehending the concept is a long rigorous mental journey. Hence, understanding concepts has been emphasized in studies in education. Previous studies demonstrate that conception has a dual nature, which has both an operational and a structural nature. We are able to acknowledge that structural conception develops from an operating conception. Nevertheless, discovering a dual nature of conception and knowing whether students acquired the dual nature, especially the structural nature are difficult to achieve. In this research, I examine the operational and the structural nature of a center of mass conception and analyze whether students acquire structural nature of the center of mass conception, and find implications which we would do to build the structural conception on a concept.

Reliability Analysis for Nonlinear Behavior of Steel Plate using Commercial Structural Software (상용프로그램을 이용한 강판의 비선형 거동에 대한 신뢰성해석)

  • 박석재;김요숙;신영수
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2001.10a
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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.

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The needs for advanced sensor technologies in risk assessment of civil infrastructures

  • Fujino, Yozo;Siringoringo, Dionysius M.;Abe, Masato
    • Smart Structures and Systems
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    • v.5 no.2
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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.

The Effects of Parenting Behavior and Peer Relationships on Adolescent Self-Concept Development (부모의 양육행동과 또래관계가 청소년 자아개념에 미치는 영향)

  • Lee, Sa-Rah;Oh, Yun-Jin
    • Journal of the Korean Home Economics Association
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    • v.46 no.9
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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.

Evaluation of Structural Integrity and Performance Using Nondestructive Testing and Monitoring Techniques

  • Rhim, Hong-Chul
    • Journal of the Earthquake Engineering Society of Korea
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    • v.2 no.3
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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.

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Application of the compressive-force path concept in the design of reinforced concrete indeterminate structures: A pilot study

  • Seraj, Salek M.;Kotsovos, Michael D.;Pavlovic, Milija N.
    • Structural Engineering and Mechanics
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    • v.3 no.5
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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.