• Journal of Welding and Joining
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• 제33권3호
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• pp.75-80
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• 2015

Self-piercing riveting is an joining method of advanced high strength steels (AHSS) and other dissimilar materials. It has attracted considerable interest from the automotive industry. The SPR has become an interesting alternative joining technique for difficult to weld materials such as steels and aluminium alloys. In this paper, self-piercing rivet and anvil for SPR were designed for the joining conditions with AHSS and aluminium alloy. Various conditions of SPR were simulated for the design of rivets and anvils. The simulated results were in good agreement with experimental ones. As a result, over HV500 rivet is desirable to joint SPFC780 AHSS and aluminum alloy.

• ETRI Journal
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• 제39권2호
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• pp.245-254
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• 2017

In-band full-duplex (IFD) communication has recently attracted a great deal of interest because it potentially provides a two-fold spectral efficiency increase over half-duplex communications. In this paper, we propose a novel digital self-interference cancelation (DSIC) algorithm for an IFD communication system in which two nodes exchange orthogonal frequency-division multiplexing (OFDM) symbols. The proposed DSIC algorithm is based on the least-squares estimation of a self-interference (SI) channel with block processing of multiple OFDM symbols, in order to eliminate the fundamental and harmonic components of SI induced through the practical radio frequency devices of an IFD transceiver. In addition, the proposed DSIC algorithm adopts discrete Fourier transform processing of the estimated SI channel to further enhance its cancelation performance. We provide a minimum number of training symbols to estimate the SI channel effectively. The evaluation results show that our proposed DSIC algorithm outperforms a conventional algorithm.

• International Journal of Contents
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• 제15권4호
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• pp.97-106
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• 2019

EMI (English as a Medium of Instruction) classes are now accepted policy at Korean universities, yet students often struggle with required academic English writings. The present study examined an EMI class that used direct instruction and access to online assistive English writing software. From preliminary analysis, 26 students expressed interest in how an EMI academic writing class could facilitate improved English writing skills. Study participants completed a survey on self-efficacy and learning needs and assignments for an EMI academic writing class. To establish inter-rater reliability, three trained raters assessed the written essays of students prior to and after instructional intervention. Fleiss' Kappas statistics showed moderate reliability. Students' opinions on the use of online software were also analysed. Paired t-test was run on the quality of students' pre- and post-instruction assignments, and there was significant difference in the rated scores. Self-efficacy was found to have moderate positive association with improved post-essay writing scores.

• 한국수학교육학회지시리즈A:수학교육
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• 제47권4호
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• pp.467-486
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• 2008

The purpose of this study is to investigate effectiveness of the cyber home study to improve the self-directed learning ability. For this study, 21 middle school students took voluntarily part in the 4 weeks cyber home study in Wulsan teaching & learning center and 3 students were interviewed among them. The results of this study were as follows; First, the 4-weeks experimental cyber home study is shown to be effective for improving the self-directed learning ability, specialty for the intermediate and low level students, Second, it is shown that the cyber home study enable students to have positive attitude as well as interest and confidence in the mathematical learning.

• Smart Structures and Systems
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• 제6권9호
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• pp.1041-1056
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• 2010

This paper investigates the possibility of a strategy for an automatic full recover of a structural component undergoing loading-unloading (fatigue) cycles: full recover means here that no replacement is required at the end of the mission. The goal is to obtain a material capable of self healing earlier before the damage becomes irreversible. Attention is focused on metallic materials, and in particular on shape memory alloys, for which the recovering policy just relies on thermal treatments. The results of several fatigue tests are first reported to acquire a deep understanding of the physical process. Then, for cycles of constant amplitude, the self-healing objective is achieved by mounting, on the structural component of interest, a suitable microcontroller. Its input, from suitable sensors, covers the current stress and strain in the alloy. The microcontroller elaborates from the input the value of a decisional parameter and activates the thermal process when a threshold is overcome.

• 가족자원경영과 정책
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• 제9권4호
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• pp.113-132
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• 2005

The objective of this research is to improved self-esteem of matriarch, and it focused on the verification of its effect by implementing a group program. The followings are the results. First of all, the matriarchs who participated in the program experienced an increase in their self-esteem, compared to the level before the program. Secondly, as each session passed, the cohesion of the group members became stronger, and both interest ana participation in the program increased. Thirdly, in terms of the individual changes of the group members, they all deviated from the past condition of being overly cautious around each other, and started to display the formation of harmonious personal relationships, showing appreciation and encouragement towards each other.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제27권1호
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• pp.111-127
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• 2024

There is an increasing concern in the United States regarding the workforce's ability to maintain a competitive position in the global economy. This has led to an increased interest in effective science, technology, engineering, and mathematics (STEM) education. The purpose of this study was to investigate the effect of STEM project-based learning (PBL) on students' self-regulation and motivation to learn. Secondary students (n = 60) participated in a STEM summer camp in which STEM PBL was utilized. Results showed that students increased their self-regulation skills (t = 2.83, df = 59, p = .004) and motivation (t = 2.25, df = 59, p =.004), with Cohen's d effect sizes of 0.395 and 0.404, respectively. Student-centered learning and peer collaboration while solving real-world problems were likely the greatest contributing factors to the outcomes. Educators should utilize the results to provide opportunities for students to experience STEM PBL.

• 복식문화연구
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• 제20권4호
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• pp.515-528
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• 2012

The purpose of this study was to classify appearance management attitudes into groups and analyze the difference of self-efficacy and body satisfaction by the groups. Questionnaires were administered to 255 college students living in Deagu Metropolitan City and Kyungbook province. The data collected were analyzed by using frequency, factor analysis, cluster analysis, correlation analysis, ANOVA, Duncan-test, t-test, and ${\chi}^2$-test. The findings were as follows. Appearance management attitudes of college students were classified into three groups such as group health body, low body interest group, emphasizes collective body. The appearance management attitudes showed significant correlation with the sub-variables of self-efficacy and body satisfaction. Male students showed no significant difference in self-efficacy by the groups while female students showed a significant one in task performance which was a sub-variable of self-efficacy. Both of the male and female students showed a significance of difference in the gap between actual and ideal weight which was a sub-variable of body satisfaction by the groups. Gender of college students showed distinction between the sub-variables of self-efficacy factors such as task performance, and anxiety and body satisfaction such as BMI, the difference between current height and ideal height, the difference between current weight and ideal weight.

• 대한가정학회지
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• 제49권10호
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• pp.71-79
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• 2011

When adolescents undergo the period of transition, they need to promote self-confidence from social support by parents, teachers or friends. It was believed that boosting subjective perception on their main areas of interest such as academic performance, appearance and fashion will result in happiness. The main purpose of this study was to investigate the influence of social support including family support, teacher support and friend support on self management, appearance satisfaction and fashion opinion leadership. A total of 412 questionnaires from the middle and high school students living in or near Seoul were collected and analyzed. The results indicated that teacher support and family support had a positive effect on self-management and family support had a positive effect on appearance satisfaction. Furthermore, friend support had a positive effect on fashion opinion leadership. In conclusion, implications for promoting self-confidence related to self-management, appearance satisfaction and fashion opinion leadership with the help of social support are suggested.

• 대한가정학회지
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• 제49권5호
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• pp.97-115
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• 2011

The focus of this study was on the self-differentiation level of families with an elderly member suffering from dementia. Based on 340 questionnaires collected in Seoul and Gyeonggi, the study intended to explain the adaptation issues of those families. The variables of interest, which might be related to the self-differentiation, were chronic anxiety(i.e. stress), the family function, psychosomatic symptoms and the family's adaptation to care-giving. As a result of analyzing the effects of the variables potentially related to the self-differentiation level of care-giving families, the findings from this study were as follow. With decreasing self-differentiation level of the family caring for an elderly member suffering from dementia, the levels of stress and psychosomatic symptoms were significantly increased, but the family function and the adaptation to care-giving tended to decrease. Conversely, with increasing self-differentiation, the levels of stress and psychosomatic symptoms were significantly decreased, while the family function and adaptation to care-giving were promoted.