• Composites Research
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• v.35 no.2
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• pp.61-68
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• 2022

Composite materials have been used in aerospace industry and many applications because of many advantages such as specific strength and stiffness and corrosion resistance etc. However, it is vulnerable to impacts, these impact lead to formation of cracks in composite laminate and failure of structures. In this paper, we analyzed Mode I fracture toughness of Carbon/Epoxy laminates using acoustic emission signal. DCB test was carried out to analyze Mode I failure characterization of Carbon/Epoxy laminates, and AE sensor was attached to measure AE signal induced by failure of specimen. Fracture toughness was calculated using cumulative AE energy and measured crack length using camera. The calculated fracture toughness was applied in FE model and the result of FE analysis compared with DCB test results. The results show good agreement with between FEM and DCB test results.

• Journal of Korean Library and Information Science Society
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• v.45 no.4
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• pp.95-117
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• 2014

A number of studies have emphasized the importance and values of reading in character education. However, there is no tool or framework for developing character education program. If teacher librarian to develop a character education program by reading should be preceded the framework for a comprehensive and systematic approach. The framework for character education program by reading is required to develop a program. The framework must be considered with a character factor and reading elements. The purpose of this study is to establish a framework that will help teacher librarian to develop a character education program by reading. This study analyzed on construction elements of character, reading material for character education, reading strategies, teaching methods. Then, this study propose a framework for developing character education program based on the analysis information. The proposed framework in this study consists of construction elements of character, reading material for character education, reading strategies, teaching methods.

• Journal of Digital Convergence
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• v.12 no.5
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• pp.403-413
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• 2014

This study is to select educational films suitable for enhancing creativity and personality in order to develop educational contents aimed at pre-service early childhood teacher. First, three film critics based on sub-elements of ego-identity selected final 59 films. Next, three education experts classified the 59 films into small groups based on components each for creativity and personality. As a result, first, films classified according to pre-service early childhood teacher' sub-elements of ego-identity, educational components for creativity, and educational components for personality were 8 in job, 7 in religion, 6 in politics, 7 in philosophical life style, 8 in friendship, 8 in relationship, 7 in gender role, and 8 in leisure activity. Second, verifying suitability of film critics and education experts using Delphi method in order to select educational films to enhance pre-service early childhood teacher' creativity and personality based on films was effective in increasing validity of the results of this research.

• Journal of the Korea Concrete Institute
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• v.13 no.2
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• pp.161-167
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• 2001

It is difficult to obtain accurate fracture toughness values using three point bending test(TPB) proposed by RILEM committees because the shape of load-deflection curve is irregular and final crack propagation occurs after some slow stable cracking. However, fracture toughness is easily obtained from crack initiation load in the disk test. In this paper, the fracture properties of high strength concrete disks with center-crack was investigated. For this purpose, the experimental results were compared with the results by finite element analysis(FEA). And the experimental fracture locus was compared with theoretical fracture locus. Also, the results of fracture properties for the degree of concrete strength are presented. It is concluded from this study that results from FEA with maximum stress theory were compared well with the results from experiment. And the degree of concrete strength was contributed to the crack initiation load and fracture toughness, but was not contributed to the failure angle. Also, The discrepancy of fracture locus between the maximum stress theory and the experiment for concrete is considered to depend upon a large energy requirement for inducing the mixed-mode and sliding mode fractures.

• Journal of Korean Home Economics Education Association
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• v.30 no.3
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• pp.91-109
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• 2018

This research aimed to develop teaching-learning plans applying character education components and STAD cooperative learning strategy focusing on the 'Housing and residential environment' unit in accordance with the 2009 revised Technology·Home Economics curriculum. In order to achieve the purpose of the research, this study was conducted in order of analysis, design, development, and evaluation. The results of this study is as follows. First, at the analysis stage, relevant literature, Technology·Home economics curriculum, and the contents of "housing and residential environment" unit from 12 textbooks published by 12 publishers were analyzed. Second, at the design stage, teaching-learning plans, teaching materials, and learning activity sheets applying character education components and STAD cooperative learning strategy were designed to increase the interest degree of the learner and character of middle school students. Third, at the development stage, a total of 8 classes of teaching-learning plan was developed. In the evaluation stage, the primary and secondary validity evaluation procedures were done by Home Economics education professors and Home Economics teachers. Teaching-learning plans and learning activity sheets were revised and complemented based on the feedback from the first validity evaluation. As a result of secondary validity evaluation, it can be seen that the teaching-learning plans and learning activity sheets developed in this research are reasonable and suitable for improving character of middle school students. It is expected that these teaching materials applying STAD and character education components will be utilized as a helpful source for curriculum developers and in-service teachers.

• Journal of Korean Home Economics Education Association
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• v.24 no.2
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• pp.117-134
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• 2012

The purpose of this study was to identify the stage of concern, the level of use, and the innovation configuration of Home Economics teachers regarding creativity and personality education in Home Economics(HE) classes. The survey questionnaires were sent through mails and e-mails to middle-school HE teachers in the whole country selected by systematic sampling and convenience sampling. Questionnaires of the stages of concern and the levels of use developed by Hall(1987) were used in this study. 187 data were used for the final analysis by using SPSS/window(12.0) program. The results of the study were as following: First, for the stage of concerns of HE teachers on creativity and personality education, the information stage of concerns(85.51) was the one with the highest response rate and the next high in the following order: the management stage of concerns(81.88), the awareness stage of concerns(82.15), the refocusing stage of concerns(68.80), the collaboration stage of concerns(61.97), and the consequence stage of concerns(59.76). Second, the levels of use of HE teachers on creativity and personality education was highest with the mechanical levels(level 3; 21.4%) and the next high in the following order: the orientation levels of use(level 1; 20.9%), the refinement levels(level 5; 17.1%), the non-use levels(level 0; 15.0%), the preparation levels(level 2; 10.2%), the integration levels(level 6; 5.9%), the renewal levels(level 7; 4.8%), the routine levels(level 4; 4.8%). Third, for the innovation configuration of HE teachers on creativity and personality education, more than half of the HE teachers(56.1%) mainly focused on personality education in their HE classes; 31.0% of the HE teachers performed both creativity and personality education; a small number of teachers(6.4%) focused on creativity education; the same number of teachers(6.4%) responded that they do not focus on neither of the two. Examining the level and type of performance HE teachers applied, the average score on the performance of creativity and personality education was 3.76 out of 5.00 and the mean of creativity component was 3.59 and of personality component was 3.94, higher than standard. For the creativity education, openness/sensitivity(3.97) education was performed most and the next most in the following order: problem-solving skill(3.79), curiosity/interest(3.73), critical thinking(3.63), problem-finding skill(3.61), originality(3.57), analogy(3.47), fluency/adaptability(3.46), precision(3.46), imagination(3.37), and focus/sympathy(3.37). For the personality education, the following components were performed in order from most to least: power of execution(4.07), cooperation/consideration/just(4.06), self-management skill(4.04), civic consciousness(4.04), career development ability(4.03), environment adaptability(3.95), responsibility/ownership(3.94), decision making(3.89), trust/honesty/promise(3.88), autonomy(3.86), and global competency(3.55). Regarding what makes performing creativity and personality education difficult, most HE teachers(64.71%) chose the lack of instructional materials and 40.11% of participants chose the lack of seminar and workshop opportunity. 38.5% chose the difficulty of developing an evaluation criteria or an evaluation tool while 25.67% responded that they do not know any means of performing creativity and personality education. Regarding the better way to support for creativity and personality education, the HE teachers chose in order from most to least: 'expansion of hands-on activities for students related to education on creativity and personality'(4.34), 'development of HE classroom culture putting emphasis on creativity and personality'(4.29), 'a proper curriculum on creativity and personality education that goes along with students' developmental stages'(4.27), 'securing enough human resource and number of professors who will conduct creativity and personality education'(4.21), 'establishment of the concept and value of the education on creativity and personality'(4.09), and 'educational promotion on creativity and personality education supported by local communities and companies'(3.94).

• Journal of The Korean Association For Science Education
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• v.36 no.4
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• pp.581-589
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• 2016

This research aims to find directions for character education in science education and to analyze Nature-Study theoretically as one of the ways to implement character education in science education. In order to accomplish this, references for character education were collected and analyzed to derive the directions for character education in science education, and then the results were verified by expert workshops composed of 2 science education experts and 4 PhD students. Through the consideration of references for Nature-Study in terms of character education, we supposed to confirm that Nature-Study is an efficient way to implement character education in science education. The research resulted in the following: First, science education should establish it's own role in character education by expanding the domains of value and realizing practice-centered character education. Accordingly, 'Expanded model of character education (The domains of the value)' was developed on the basis of 'formation of relationships' with 'nature & environment, spiritual object' and 'The practice-centered character manifested mechanism' empathized 'formation of relationships' and 'practice' was also diagramed. Second, Nature-Study empathized 'Science Education through Nature' can be one of the efficient ways to implement character education in science education. Nature-Study corresponds with the directions of character education in science education because Nature-Study aims for character education in it's educational purpose and emphasizes 'formation of relationships' with 'nature & environment' and 'practice' in the real world. In conclusion, science education should establish it's own role in character education by expanding the domains of value and realizing the practice-centered character education and Nature-Study is efficient ways to implement character education in science education.

• Magazine of the Korea Concrete Institute
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• v.9 no.3
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• pp.179-187
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• 1997

콘크리트는 여러 구성 성분들이 불규칙적인 배열을 이루어 형성된 복합재료이지만, 과거에는 이 재료를 하나의 단종재료로 간주하여 해석하였기 때문에, LEFM에서 사용되는 파괴인성계수만으로는 콘크리트의 파괴역학적 접근이 어렵다는 것 이외에는 파괴인성계수들의 크기의존성에 대한 이유라든가, 실험을 통해서 관측된 구조물 두께 방향으로의 서로 다른 깊이의 균열 진행 현상에 대해서는 설명하기가 어려웠다. 따라서 본 연구는 콘크리트를 하나의 복합재료로써 각각의 구성요소들이 차지하고 있는 체적비 및 배열상의 효과를 고려하여 복합재료의 파괴거동을 해석하고, 구성재료의 수와 파괴인성계수와의 상관관계를 분석하였다. 각각의 구성요소들을 연립변형모드( SD mode)로 배열시킨 조건에서 복합재료역학개념에 입각하여 해석한 결과, 일반적으로 실험이나 비선형파괴역학 해석과 같이 하중-변위곡선 상단부에서 비선형 거동이 관측되었다. 또한 임계응력확대계수( $K_IC$)나 파괴에너지($G_r$)는 구성원의 수나 보의 크기에 대해서 거의 무관한 값을 나타내지만, 임계군열선단개구변위 ($CTOD_c$)는 크기에 영향을 받음을 보여 주었다. 균열의 진행속도는 균열이 진행될수록 감소하며, 파괴인성이 작은 구성원에서부터 균열이 발생되어 결과적으로 보의 두께 방향으로 서로 다른 크기의 균열길이가 생성됨이 관측되었다.

• Tunnel and Underground Space
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• v.29 no.6
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• pp.523-531
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• 2019

In the applications of rock mechanics or rock engineering including drill and blast, drilling and mechanical excavation, the fracture toughness is an important factor. Several methods have been proposed to measure the fracture toughness of rocks. In this study, wedge splitting test specimen which is prepared with ease and tested under compression loading was used to obtain mode I fracture toughness of rocks. The equation of stress intensity factor through numerical analysis is proposed from the stress state of crack tip considering both vertical and horizontal loads due to the vertical load acting on the wedge. The validity of the wedge splitting test method was confirmed by comparing the mode I fracture toughness values obtained by the GD and SENB test specimens.

• Education of Primary School Mathematics
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• v.19 no.4
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• pp.261-276
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• 2016

This study was to investigate the effects of peer mentoring on students' mathematical characters and mathematics achievements in mathematics class. The participants were twenty four 6th grade elementary students at the S school in Sungbuk-Gu, Seoul, Korea. They were divided into 4 groups according to the combination of groups. The researchers analyzed the experimental group and the control group with covariances on the sub-factors of the mathematical characters such as respect, caring, sharing, and openness. However, there were no statistically significant changes. However, with the help of the two analyses on the mathematical logs and the worksheets which had been carried out in advance by the quantitative and qualitative research methods, the researchers investigated how the peer mentoring-applied instructions would change the mathematical characters for each sub-factor in detail. In conclusion, the peer mentoring-applied instructions makes a positive contribution to the students' mathematical character and mathematical academic achievements. We suggest that peer mentoring in mathematics lessons should be adopted in various mathematical ability levels of students.