• 한국환경보건학회지
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• 제20권4호
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• pp.17-35
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• 1994

This study was performed to investigate and assess the heavy metal contamination of sediment in main stream and tributaries of the Han-river in the vicinity of Seoul. Sediment were sampled at eight locations of main stream and eighteen locations of tributaries in the spring, summer, and fall in 1993. Six heavy metals of Cd, Cu, Pb, Zn, Cr, and Hg, were assessed. For an assessment of heavy metal contamination in sediment, the assessment method of Hakanson was modified to estimate for Han-river, then classification method of Muller in sediment quality was applied. For an assessment of contamination in each heavy metal, Contamination factor C$_f^i$ which was defined the ratio of concentration of i heavy metal in investigated location to background concentration of i heavy metal in uncontaminated upper area was used. The sediment quality in each heavymetal was classified as follows if C$_f^i$<1, Class I for Non contamination, if 1 < C$_f^i$ < 3, Class II for Low contamination, if 3< C$_f^i$ <6, Class III for Moderate contamination, if 6< C$_f^i$ <12, Class IV for Considerable contamination, and if C$_f^i$ > 12, Class V for High contamination.(abbreviation)

• 대한가정학회지
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• 제28권4호
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• pp.103-117
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• 1990

The purpose of this study was to investigate the difference of mid-life family stress and family coping strategies according to conjugal sex and social class. This study was also intended to examine the relations between mid-life family stress and family coping strategies. The subjects of this study were 150 married couples(300 persons) who were 40 to 59 years old in Seoul. McCubbin, Wilson & Patterson (1979)'s "Family Inventory of Life Events and Changes" and McCubbin, Larsen & Olson (1982)'s "Family Coping Strategies" were used to gather data for the study. For the statistical analysis of data, factor analysis, T-test, Duncan's multiple Range Test, Pearson's r and cronbach's α for reliability were performed. The major results of this study were summarized as follows; 1. There were significant differences according to conjugal sex and social class in family stress; Wives reported more family stress than husbands. And the lower social class of the family, the more family stress were found. 2. There were some significant differences according to conjugal sex and social class in family coping strategies; Wives reported more family coping strategies than husbands in "freind and neighbor's support", "religious support". And the lower social class of the family, the more "passive attitudes" were found. 3. There were some significant correlations between family stress and family coping strategies; The higher extent of the total family stress, the lesser positive attitudes were found.

• 한국전자파학회논문지
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• 제26권6호
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• pp.593-596
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• 2015

본 논문은 무선전력전송 시스템에 활용할 수 있도록 낮은 드레인 전압에서 높은 효율을 가지는 class E 전력증폭기를 설계하였다. 붕괴전압이 40 V인 Si MOSFET을 이용하여 드레인 바이어스 전압이 12.5 V인 13.56 MHz 전력증폭기를 설계하였다. 출력 전력 및 효율을 개선하기 위하여 품질계수가 우수한 솔레노이드 인덕터를 제작하여 출력 정합회로에 사용하였다. 발진 방지와 간단한 회로 구성을 위하여 인덕터와 저항으로 입력 정합회로를 구성하였다. 측정 결과, 제작된 전력증폭기는 13.56 MHz에서 38.6 dBm의 출력전력과 16.6 dB의 전력이득, 그리고 89.3 %의 높은 전력부가효율을 보였다.

• 수산해양교육연구
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• 제28권6호
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• pp.1529-1548
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• 2016

The objective of this study is to explore an effect of class teaching method of utilizing a pictogram on understanding of safety terms by the Hearing Impaired students. For this objective, a class teaching utilizing a pictogram was performed by targeting 4 students (elementary school 6th graders)with auditory disability for app. 3 months during the period from July, 2015 to September and through repeated measurement, an effect of class teaching utilizing pictogram on their understanding of safety terms was analyzed. The result of this study is as follows. First, class teaching utilizing pictogram was effective for enhancing understanding of safety terms. Second, such teaching was effective for promoting interest in safety terms. Through these results, it could be concluded that such teaching method provided an opportunity of enhancing understanding of the students with auditory disability for safety terms. In addition, the result of this study implies that pictogram teaching method being designed to deliver the meaning of target easily and promptly becomes a major factor of exerting a positive influence on understanding of safety terms by the students with auditory disability.

• 국토계획
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• 제54권1호
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• pp.52-66
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• 2019

Travel is a factor that stimulates the vitality of the urban and is widely used as an indicator of sustainable growth of the region. In Korea, however, no studies has been made to predict changes in traffic and calculate the accessibility of the region by comprehensively considering the socio-economic conditions of the travelers. The purpose of this study is to classify commuters according to the household income and to analyse the traffic characteristics of each class. The analysis results are aggregated into two. First, the analysis of study found different transport characteristics for different income classes. This is the result that underpins the argument of a previous study that suggested that a discriminatory approach is necessary for each income in determining the accessibility of the region. Second, this study calculated utility values differently for each income class based on the transit time and cost required between each zone. Through these measures, transport characteristics were analyzed by income class using indicators that considered transportation infrastructure, and socio-economic conditions of the travelers. This study is meaningful in that it provided the basis for calculating the accessibility that could take into account the activities of the housing consumers in establishing domestic housing policies.

• 공학교육연구
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• 제26권6호
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• pp.51-61
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• 2023

In this study, the effects of pre-learning attitude on learning participation and academic achievement was analyzed when applying the flipped learning methodology to engineering subject education. The modified PARTN teaching and learning model was applied, and pre-class survey, assessment on learning in pre-class, and post-class survey were conducted to analyze the effectiveness of flipped learning. The results were analyzed for 24 students who took the applied thermodynamics lecture. They were asked to take the course with the videos provided in the pre-class stage, and a pre-learning assessment was conducted to measure the completeness and understanding of the learning. As a result of the study, it was found that students with relatively excellent learning ability had excellent pre-learning evaluation results and excellent final academic achievement. In addition, the lower the pre-learning completion rate within the pre-learning period or the higher the learning rate using mobile devices, the more difficult it was to faithfully complete pre-learning, leading to poor pre-learning evaluation results. Meanwhile, the survey revealed that conducting pre-learning assessments were helpful in encouraging individual learning. In addition, cases reflecting pre-learning evaluation results to course grades showed higher pre-learning evaluation results than cases not reflecting pre-learning evaluation results to course grades, and in flipped learning classes, pre-learning evaluations act as a factor that promotes pre-class learning.

• 농업과학연구
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• 제49권4호
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• pp.1015-1031
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• 2022

The objectives of this study were to classify the types of elderly households and to compare the characteristics of their dietary lifestyle. Panel data surveyed by Korea Rural Economic Institute (KREI) for Food Purchase Attitudes over three years (2019 - 2021) were utilized for the analysis. Through a factor analysis, five common factors were extracted out of 19 basic variables related to dietary style, which indicate two kinds of consumer competency index (safe diet, traditional diet) and three kinds of purchase frequency (healthy food, meat & fish, fresh seafood). Applying the cluster analysis method, by using socioeconomic variables along the five common factors, elderly households aged 60 or older were grouped into four types. As a result, Type 1 elderly households accounted for 50.8%, Type 2 for 16.2%, Type 3 for 27.8%, and Type 4 for 5.2% out of all 870 elderly households. Type 1 is characterized as a low-income vulnerable class with a poor diet, Type 2 as a middle-income class with a healthy food-oriented diet, whereas Type 3 was classified as a middle-income class with a meat-oriented diet, and Type 4 as a high-income class with diverse dietary culture. It is necessary to expand the agri-food voucher pilot project to the entire country and also increase the monthly subsidy for the Type 1 elderly households. Implementing community kitchen projects for elderly single-person households, promoting senior internships by providing incentives to companies that employ retirees, the provision of education by local governments on a safe and balanced diet for Types 2 and 3, and the promotion of an elderly-friendly social environment are also recommended.

• 대한소아치과학회지
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• 제33권4호
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• pp.693-698
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• 2006

유구치 1급 와동의 복합레진 수복 시 C-factor가 가장 크게 나타나며 중합수축에 의한 응력도 가장 크게 나타난다. 이 실험에서는 응력이 각 와동벽 위치에 따라 다르게 나타나는 양상을 microtensile bond strength(MTBS)실험을 통해 확인해보았다. 하악 제2유구치 20개를 두 개의 군으로 나누었다. 각각 다른 종류의 복합레진으로 수복하였고 개별 치아에서 각각 치수벽 시편과 축벽 시편을 얻어 총 4개의 군으로 나누었다. MTBS를 측정하였으며 통계적 유의성을 student T-test를 통해 검정하였다. ZP: Filtek Z250- 치수벽, ZA: Filtek Z250- 축벽, SP : Filtek Supreme - 치수벽, SA: Filtek Supreme - 축벽, 다음과 같은 결과를 얻을 수 있었다. 1. ZP군과 ZA군, SP군과 SA군 사이에서는 유의한 차이가 존재하였다(p<.001). 2. ZP군과 SP군, ZA군과 SA군 사이에서는 유의한 차이가 존재하지 않았다(p<.001).

• 디지털융복합연구
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• 제14권5호
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• pp.473-483
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• 2016

이 연구는 교양스키수업에 참가하는 대학생들의 스포츠 자신감과 운동열정 및 재 참여의도와의 관계를 구명하는데 목적이 있다. 연구의 목적을 달성하기 위해서 교양스키수업에 수강신청을 한 대학생들을 모집단으로 설정하여 416명을 대상으로 설문조사를 실시하였으며, 수집된 자료는 SPSS 18.0프로그램을 이용하여 설문지의 신뢰도와 타당도검사, 기술통계분석과 상관분석을 실시하였으며, AMOS 18.0을 이용하여 경로분석을 실시한 결과 다음과 같은 결과를 도출하였다. 첫째, 교양스키수업에 참가하는 대학생들의 스포츠 자신감은 운동열정에 정적인 영향을 미친다. 둘째, 교양스키수업에 참가하는 대학생들의 스포츠 자신감은 재 참여의도에 영향을 미친다. 셋째, 교양스키수업에 참가하는 대학생들의 운동 열정은 재 참여의도에 정적인 영향을 미친다. 넷째, 교양스키수업에 참여하는 대학생들의 스포츠 자신감, 운동열정 및 재 참여의도 사이에는 인과적 관계가 있다.

• 한국식품영양학회지
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• 제25권4호
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• pp.719-728
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• 2012

This study focused on the yearly-dietary habits, nutrition status, and health of female students residing in Seoul. A number of classes were assess based on their dietary behaviors in oder to attempt to determine differences in their attitudes to nutrition, according to age. The students of class 2011 (sophomore) ate meals more regularly than the female students of the 2008 class (p<0.05). It was found that sophomore female students of class 2008 consumed higher than average nutrient intake. Sophomore female students of the 2011 class consumed lower than average vitamin $B_2$, C, Ca, and Fe intakes. Folic acid in take was lower than average in both groups. Phosphorus and sodium intakes in both groups were excessive (p<0.05). When surveyed, sophomore female students of the 2008 class believed that the most important thing for health was exercise, whereas students of class 2011 believed that nutrient intake was the most important factor (p<0.05). Female students of the 2008 class exercised 1~2 times a week generally, whereas students of class 2011 exercised three times (43.2%) (p<0.05). Therefore, it is necessary to study changes in dietary habits and health status according to the age of students, and develop specific nutrition education programs for female students.