• 한국구조물진단유지관리공학회 논문집
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• 제23권4호
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• pp.137-144
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• 2019

취성재료인 탄소섬유보강폴리머(CFRP)의 시편시험에서 총변형량과 유효길이로서 유도되는 환산변형률을 도입하고, 환산변형률의 장점을 기술하였다. 일반적으로 재료의 인장물성을 결정하기 위해 스트레인 게이지 측정값을 사용하지만, 취성특성을 가지는 CFRP에서는 항상 유효한 것은 아니다. 그 이유는 취성재료에서는 응력재분배를 할 수 없으며, 스트레인 게이지의 측정값은 국부거동만을 나타기 때문이다. 따라서 환산변형률은 취성재료의 인장인장특성의 평균값을 측정하고 변형률과 측정값을 검증하는 보조지표로서 효과적으로 사용될 수 있다. 또한 환산변형률은 1) 제작 오차(편차) 와 세팅 오차(정렬 불량)에 의해 발생하는 초기 내부 변형률에 기인한 영향과 2) 불균일 변형분포로 인한 부분파단 이후 거동을 명확히 가시화하는 장점이 있다.

• International Journal of Advanced Culture Technology
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• 제8권4호
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• pp.89-94
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• 2020

This study attempted to investigate cognitive load, vividness, and cybersickness in nursing students, in the last year of nursing college, who used a 360-degree video content for studying intravenous fluid infusion, one of the core fundamental nursing skills. The aim was to determine the correlation between the variables, and to decide whether the 360-degree video content can be used as an effective supplementary educational material in the regular curricula. This study, a descriptive research, was conducted from October 31, 2019 to November 14, 2019. The participants in this study were 64 students in the 4th year of nursing college at a university located in B City, South Korea. They were instructed to watch a 360-degree video content for intravenous infusion using a Samsung Head Mounted Display (HMD) while ensuring the safety of the students. The results showed that the scores, out of 7 points, for material design, self-evaluation, and physical effort for cognitive load in nursing students were 5.93±0.71, 5.92±0.71, and 5.64±0.74 points, respectively. In addition, the scores, out of 7 points, for mental effort and task difficulty were 2.55±1.08 and 1.94±0.75 points, respectively, and the scores for vividness and cybersickness in the participants were 5.82±0.84, and 2.57±0.98 points, respectively. Physical effort, self-evaluation, and material design for cognitive load in the participants were positively correlated with vividness (r=.379, r=.458, r=.507). In addition, mental effort for cognitive load was positively correlated with cybersickness (r=.684), whereas self-evaluation and material design were negatively correlated with cybersickness (r=-.388, r=-.343). Based on the results of this study, we believe that the 360-degree video content for intravenous fluid infusion can be used as an educational medium in regular and non-regular curricula. In addition, future studies are needed to specifically develop and verify teaching and learning methods on how to apply 360-degree video contents..

• 문화기술의 융합
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• 제6권1호
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• pp.477-483
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• 2020

콘크리트 박스 구조물이 열화되어 보수보강이 필요할 경우 스프레이 장비로 구조물 단면에 보수재를 분사하여 부착시키는 방법에 의존하고 있는데 천장 또는 벽체부위의 경우 시공 후 보수재 자중 또는 중력에 의해 부착력이 저하될 수 있으며 지하철 구조물의 경우 진동 등에 의해 초기 부착력이 떨어지는 문제점이 발생한다. 또한 작업자의 숙련도와 시공환경에 따라 보수품질이 변동되기에 이에 대한 보완책이 필요한 실정이다. 본 연구에서는 중력에 의한 보수재의 부착력 저하 및 인력시공에 의한 보수품질의 변동과 같은 문제점을 해결하고자 보수재 시공 후 소정의 압력을 가할 수 있는 기계식 가압장비를 개발하였다. 그리고 가압장비의 성능을 알아보고자 현장조건을 모사할 수 있는 챔버를 제작하여 가압 유무, 단면부위 및 환경조건을 달리한 부착강도를 측정한 결과 가압할 경우 그렇지 않은 경우보다 부위별로 차이가 있었으나 최대 70% 부착강도가 증가하는 효과를 얻을 수 있었다.

• 한국어교육
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• 제28권4호
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• pp.63-86
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• 2017

This research aims to evaluate the effects and the shortcomings of strategies for teaching paraphrasing to foreign university students. For this study, the effects of teaching paraphrasing skills on student's academic writing was investigated through the assessment of pre- and post-test writing tasks and through a focus group interview. The teaching of paraphrasing was divided into 3 instructional sessions and the focus group interview was conducted at the end of the last session. After each instructional session three trained assessors evaluated the outcomes of pre and post task writings; the in-depth focus group interviews were conducted on seven of the students in order to define better positive effects as well as shortcomings. By comparing the scores of pre- and post-task assignments it is possible to affirm that there is a meaningful difference for overall scores; moreover, in an analysis conducted on each single sub-element of the paraphrasing skill, it emerged that except for "task completion", all other four elements of "structure", "understanding core content", "change of expression" and "academic expressions" showed a statistically significant improvement in performance. On the other hand, as a result of the focus group interview, it was possible to individuate as main shortcomings insufficient vocabulary knowledge, poor overall comprehension of the reference material, lack of practice and difficulty in connect sentences organically. It is possible to consider these elements as limiting factors in understanding the reference material and making correct citations by the students. Therefore, we suggest as supplementary instructional strategies a deeper attention to the difficulty level of the text, the introduction of devices to understand better the content of the reference material and an integrated practice of the paraphrasing skill.

• 한국재료학회지
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• 제29권11호
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• pp.727-733
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• 2019

In this study, the glass melting properties are evaluated to examine the possibility of using refused coal ore as replacement for ceramic materials. To fabricate the glass, refused coal ore with calcium carbonate and sodium carbonate in it (which are added as supplementary materials) is put into an alumina crucible, melted at $1,200{\sim}1,500^{\circ}C$ for 1 hr, and then annealed at $600^{\circ}C$ for 2 hrs. We fabricate a black colored glass. The properties of the glass are measured by XRD (X-ray diffractometry) and TG-DTA (thermogravimetry-differential thermal analysis). Glass samples manufactured at more than $1,300^{\circ}C$ with more than 60 % of refused coal ore are found by XRD to be non-crystalline in nature. In the case of the glass sample with 40 % of refused coal ore, from the sample melted at $1,200^{\circ}C$, a sodium aluminum phosphate peak, a disodium calcium silicate peak, and an unknown peak are observed. On the other hand, in the sample melted at $1,300^{\circ}C$, only the sodium aluminum phosphate peak and unknown peak are observed. And, peak changes that affect crystallization of the glass according to melting temperature are found. Therefore, it is concluded that glass with refused coal ore has good melting conditions at more than $1,200^{\circ}C$ and so can be applied to the construction field for materials such as glass tile, foamed glass panels, etc.

• 영어어문교육
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• 제16권1호
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• pp.209-233
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• 2009

Many difficult literary texts have been disregarded by the teachers as well as the students in the EFL context. The abridged version, however, has its pedagogical usability when viewed as an extension of the literary text like movies and comic strips. Legible abridgments boost up the critical mind among the learners by enhancing their involvement in responding more actively to each class. In addition, to study an abridged version makes the future teachers accustomed to use it as a usable material. Abridgment has its efficacy in the literary study, too: reader-response criticism and narrative scholarship. First, the learners' creative engagement to the text encourages them to draw their personal experiences which are made up of the basic storyline. Second, a personal experience linked to the story has a relationship to narrative scholarship proposed in contemporary ecocriticism. Narrative scholarship is a new academic trend that merges the writer's personal experience in physical surroundings with the text which describes the same or similar natural environment. The role of teachers is a key to succeed in the abridged version pedagogy. They can facilitate a web of learner, text, and social context by providing a friendly atmosphere to encourage students' active participation, as well as supplementary materials of the original text.

• Computers and Concrete
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• 제19권6호
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• pp.651-658
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• 2017

High-performance concrete, besides aggregate, cement, and water, incorporates supplementary cementitious materials, such as fly ash and blast furnace slag, and chemical admixture, such as superplasticizer. Hence, it is a highly complex material and modeling its behavior represents a difficult task. This paper presents an evolutionary system for the prediction of high performance concrete strength. The proposed framework blends a recently developed version of genetic programming with a local search method. The resulting system enables us to build a model that produces an accurate estimation of the considered parameter. Experimental results show the suitability of the proposed system for the prediction of concrete strength. The proposed method produces a lower error with respect to the state-of-the art technique. The paper provides two contributions: from the point of view of the high performance concrete strength prediction, a system able to outperform existing state-of-the-art techniques is defined; from the machine learning perspective, this case study shows that including a local searcher in the geometric semantic genetic programming system can speed up the convergence of the search process.

• 한국패션뷰티학회지
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• 제5권1호
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• pp.24-33
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• 2007

This study was undertaken to find out how much influence eating habits and food preferences have on basic skin types, namely dry skin, normal skin, oily skin, and combination skin, as well as troubled skin, such as acne skin, sensitive skin, pigment disorder skin and unbalanced oil and moisture skin. The aim of this study was to help establish good eating habits and to reform food preferences in order to maintain healthy skin. For this study, a suey on the eating habits and food preferences of 206 college women in the metropolitan area was conducted. Statistics Program SPSS (ver130.0) was used to analyze the results of the material obtained from the survey. The survey revealed that participants with basic skin types ate a variety of foods, enjoy soft drinks, juice and supplementary food, while those with troubled skin types had daily breakfast and substitute snacks for meals. The survey also showed that alcohol is the dangerous factor for the cause of both sensitive skin and pigment disorder skin. And it showed that various nutrition intake is the main factor for unbalanced oil and moisture skin.

• 복식
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• 제64권7호
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• pp.143-155
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• 2014

This study focuses on Yusam, a military raincoat that was worn during the Joseon Dynasty. The purpose of this study is to review the types and management system of Yusam. Documentary records, paintings and relics were used as research materials. Yusam was recorded as either Yusam(油衫) or Yu-ui(油衣) in writing. It usually looked like a skirt and was worn like a cape, but there were differences in length. Some of them took the form of a short coat with half-sleeves and side slits. Research analysis results of Silrok, Ilseongrok and the archives of the military camp in the later Joseon are as follows: First, Mokyusam and Jiyusam coexisted as military raincoats. Mokyusam was made with cotton and perilla oil, while Jiyusam was made with traditional Korean paper, a cotton edging and perilla oil. Second, the differences between general Yusam and military Yusam include the material of the clothing, the materials for waterproofing, the color, and the manufacturer. Third, each military camp supplied soldiers with hundreds to thousands of Yusam. Military officers and King's guards wore Mokyusam because Mokyusam was higher than Jiyusam. Fourth, soldiers Yusam together with Yujeongeon, Chorip, Galmo, or Hwihang as a hat. Fifth, the higher the rank, the higher the price of Yusam and the longer the term of usage. On the other hand, as the rank got higher, the cost of the supplementary oil rose, while the duration of usage got shorter.

• Advances in concrete construction
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• 제5권3호
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• pp.241-255
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• 2017

Concrete is known to be the most used construction material worldwide. The environmental and economic aspects of Ordinary Portland Cement (OPC) containing concrete have led research studies to investigate the possibility of incorporating supplementary cementitious materials (SCMs) in concrete. Metakaolin (MK) is one SCM with high pozzolanic reactivity generated throughout the thermal activation of high purity kaolinite clay at a temperature ranging from $500^{\circ}C$ to $800^{\circ}C$. Although many studies have evaluated the effect of MK on mechanical properties of concrete and have reported positive effects, limited articles are considering the effect of MK on durability properties of concrete. Considering the lifetime assessment of concrete structures, the durability of concrete has become of particular interest recently. In the present work, the influences of MK on mechanical and durability properties of concrete mixtures are evaluated. Various experiments such as slump flow test, compressive strength, water permeability, freeze and thaw cycles, rapid chloride penetration and surface resistivity tests were carried out to determine mechanical and durability properties of concretes. Concretes made with the incorporation of MK revealed better mechanical and durability properties compared to control concretes due to combined pozzolanic reactivity and the filler effect of MK.