• Steel and Composite Structures
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• v.7 no.5
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• pp.391-404
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• 2007

This paper presents push-out tests of stud shear connectors to examine their fatigue behavior for developing a new composite bridge deck system. The fifteen push-out specimens of D16 mm stud welded on 9 mm steel plate were fabricated according to Eurocode-4, and a series of fatigue endurance test and residual strength test were performed. Additionally, the stiffness and strength variations by cyclic loading were compared. The push-out test, when the stiffness reduction ratio of the specimens was 0.95 under cyclic load, resulted in the failure of the studs. The stiffness variation of the push-out specimens additionally showed that the application of cyclic loads reduced the residual strength. The fatigue strength of the shear connectors were compared with the design values specified in the Eurocode-4, ASSHTO LRFD and JSSC codes. The comparison result showed that the fatigue endurance of the specimens satisfies the design values of these codes.

• Steel and Composite Structures
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• v.31 no.1
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• pp.53-67
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• 2019

This study presents finite element analysis (FEA) on a Y-type perfobond rib shear connection using Abaqus software. The performance of a shear connection is evaluated by conducting a push-out test. However, in practice, it is inefficient to verify the performance by conducting a push-out test with regard to all design variables pertaining to a shear connector. To overcome this problem, FEA is conducted on various shear connectors to accurately estimate the shear strength of the Y-type perfobond rib shear connection. Previous push-out test results for 14 typical push-out test specimens and those obtained through FEA are compared to analyze the shear behavior including consideration of the design variables. The results show that the developed finite element model successfully reflects the effects of changes in the design variables. In addition, using the developed FEA model, the shear resistance of a stubby Y-type perfobond rib shear connector is evaluated based on the concrete strength and transverse rebar size variables. Then, the existing shear resistance formula is upgraded based on the FEA results.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.5
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• pp.59-65
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• 2012

In this paper, we investigate the compressed sensing (CS) algorithms for modeling a super-resolution near-field structure (super-RENS) disc system with a sparse Volterra filter. It is well known that the super-RENS disc system has severe nonlinear inter-symbol interference (ISI). A nonlinear system with memory can be well described with the Volterra series. Furthermore, CS can restore sparse or compressed signals from measurements. For these reasons, we employ the CS algorithms to estimate a sparse super-RENS read-out channel. The evaluation results show that the CS algorithms can efficiently construct a sparse Volterra model for the super-RENS read-out channel.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.36 no.6
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• pp.273-279
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• 2014

Purpose: This study assessed the association between eye symptoms (enophthalmos or diplopia) and site of damage, volume, deviated inferior rectus muscle (IRM) and type of fracture with computed tomography (CT). The intent is to anticipate the prognosis of orbital trauma at initial diagnosis. Methods: Forty-five patients were diagnosed with fractures of the inferior wall of one orbit. Fracture area, volume of displaced tissue, deviated IRM, and type of fracture were evaluated from coronal CT by one investigator. The association of those variables with the occurrence of eye symptoms (diplopia and enophthalmos) was assessed. Results: Of 45 patients, 27 were symptom-free (Group A) and 18 had symptoms (Group B) of enophthalmos and/or diplopia. In Group B, 12 had diplopia, one was enophthalmos, and five had both. By CT measurement, group A mean area was $192.6mm^2$ and the mean volume was $673.2mm^3$. Group B area was $316.2mm^2$ and volume was $1,710.6mm^3$. The volume was more influential on symptom occurrence. Each patient was categorized into four grades depending on the location of IRM. Symptom occurrence and higher grade were associated. Twenty-six patients had trap-door fracture (one side, attached to the fracture), and 19 had punched-out fracture (both sides detached). The punched-out fracture was more strongly associated with symptoms and had statistically significantly higher area and volume. Conclusion: In orbital trauma, measurement of fracture area and volume, evaluation of the deviated IRM and classification of the fracture type by coronal CT can effectively predict prognosis and surgical indication.

• Journal of dental hygiene science
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• v.18 no.5
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• pp.271-279
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• 2018

This study aims to contribute to managing the human resource of dental hygienists and qualitatively enhancing dental medical services by examining factors that affect their turnover intention. Therefore, it attempted to examine their degrees of emotional labor, job satisfaction, and social support and the effects of each variable on turnover intention. This study administered self-reporting questionnaires to dental hygienists working in dental hospitals, dental clinics, and general or university hospitals in Seoul Metropolis and Gyeonggi-do by conducting convenience sampling, from May 18, 2017 to August 4, 2017. Among a total of 224 copies that were distributed, a total of 223 copies, excluding 1 copy with poor responses, were used in the data analysis. The research tools comprised 12 questions on general characteristics, 24 questions on emotional labor (4-point Likert scale), 16 questions on job satisfaction (5-point Likert scale), 8 questions on social support (4-point Likert scale), and 4 questions on turnover (5-point Likert scale). The scores of dental hygienists were as follows: emotional labor, 2.49 out of 4; job satisfaction, 3.14 out of 5; social support, 3.04 out of 4; and turnover intention, 3.07 out of 5. Their turnover intention has a positive correlation with emotional labor, but a negative correlation with job satisfaction and social support. It was found that some factors that significantly influence turnover intention included the amount of overtime work and job satisfaction. Thus, dental medical institutes should search for measures, including improvement of the working environment, to reduce the amount of overtime work and enhance job satisfaction.

• Proceedings of the Korea Contents Association Conference
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• 2014.11a
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• pp.15-16
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• 2014

제품/서비스의 전체 사용 경험 주기에서 사용자 인지와 수용에 영향력을 행사하는 첫 단계에 해당하는 OOBE(Out of Box Experience)를 Mobile App 서비스에 맞게 재구성하였다. 본 연구는 "사용자가 서비스를 획득하고(Acquire), 서비스 사용을 준비하다가(Prepare), 어느 시점에서 본격적으로 서비스를 사용하기 시작(First Use)"하는 3단계를 제시한다.

• Journal of the East Asian Society of Dietary Life
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• v.10 no.6
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• pp.548-559
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• 2000

This study was carried out through questionnaire in order to investigate the self-recognized monosodium glutamate (MSG) symptom complex in the eating out of housewives. The subjects were 503 housewives in Inchon and the results are summarized as follows. As for age, 51.9% of subjects were over 40 years old. Also 60.0% of the subjects received a high school education. As for occupation, full-time housewives accounted for 63.7%. Monthly household income of most subjects were 1 million won or more, and monthly food expenses for most subjects were over 300 thousand won or more. Also 71.0% of the subjects lived in apartments. As for frequency of eating out, 69.5% of subjects ate out I~2 times a month, 21.6% did 3~4 times a month, 4.5% did 7 times or more/month and 3.6% did 5~6 times a month. The higher education level, family income or food expense of subjects were, the more they ate out. Most subjects selected the menu of eating out according to preference of family. Also 63.6% of the subjects considered the amount of MSG in eating out. As for menus containing high amount of MSG, 55.8% of subject answered Korean dishes, 31.1% did Chinese dishes. After eating out, 25.1% of subjects perceived MSG symptom complex, such as thirst, tiredness and rapid heart beat, etc. Therefore, it may be necessary to reduce the amount of MSG in eating out and to develop safe and delicious menus of eating out using various natural foods.

• Journal of the Korean Dietetic Association
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• v.10 no.3
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• pp.345-355
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• 2004

This study was conducted to investigate the dietary pattern of children with unbalanced diet in school feeding. Children who eat only what they like among elementary school students were selected for this survey. The general characteristics, nutrition knowledge, eating behavior, food intake frequencies and food preferences of the subjects were investigated compared with control group. The subjects were consisted of a total of 160 children : 92 male students(unbalanced-diet group, 46; control group, 46), and 68 female students(unbalanced-diet group, 34; control group, 34). There was no significant difference in nutrition knowledge between the unbalanced-diet group and the control group. Dietary behavior of control group turned out to be more desirable than that of the unbalanced-diet group. In addition, 68.7% of the unbalanced-diet group and 13.8% of the control group hated to eat vegetables. The result of food intake frequency indicates that the control group turned out to be higher in their intake of fish, cereals, vegetables, seaweeds, fats & oils and Kimchi compared with unbalanced-diet group. Intake frequency of minerals and vitamins of the control group was higher than that of the unbalanced-diet group. On the other hand, the unbalanced-diet group turned out to be higher in sugar intake. Children showed the greatest preference of fruits. The unbalanced group turned out to prefer sugar and beverages more than the control group. These results suggest that the desirable dietary habits of children should be formed with the help of nutrition education designed for behavior modification.

• Journal of the Korean Home Economics Association
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• v.38 no.8
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• pp.85-97
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• 2000

The purpose of this study was to evaluate the dietary attitude and food behavior of elementary, middle and high school students in Korea. The subjects in this study were 7,698 boys and girls in large cities in Korea. The questionnaire was made and distributed to the students to answer the questions. Followings are the results of this study : 1) Father and mother's average ages were 45 and 41 years old, respectively. 2) Most students thought dietary life was more important than clothing or residentary life. Dietary habits such as irregularity of meal, frequencies of skipping meal and of eating out increased in higher grade than in lower grade, and in girls than in boys. 3) Most students, especially in elementary school, recognized that their own bad dietary habbit was unbalanced diet. Irregular meal time and eating too much were also pointed out as problems by middle and high school students. 4) Most students thought that the most effective meal for health was breakfast, but they replied the tartest meal as dinner. 5) Students tended to prefer Korean style food. Cooked rice and kimchi, ramyun, and pizza were ranked the most preferred food when they were hungry. 6) Elementary school students ate meals more regularly than higher grade students, and girls ate meals more regularly than boys. 7) Skipping rate of breakfast was higher than that of lunch or dinner, and the percentage of meal skipping students was increasing with grade elevation. No time to eat or eating between meals was the reasons of irregular meal time. 8) Frequency of dining with family was decreased, but frequency of eating out with friends was increased with increasing grade. The gravity of dining out is increasing rapidly in Korean adolescents. Therefore, nationwide nutrition education policy is necessary to constitute a right dietary environment and a desirable dietary altitude.

• Korean Journal of Community Nutrition
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• v.26 no.2
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• pp.111-121
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• 2021

Objectives: This study examined ways to promote desirable eating habits by choosing foods with low sugar contents and provide nutrition education in adolescents. Methods: This study was a cross-sectional survey. The sugar reduction perception and knowledge, sugary food preference, and intake frequency of 487 male and female high school students in Incheon were analyzed comparatively. Results: Approximately 94.9% and 94.5% of the subjects were unaware of the promotion of a sugar reduction policy and the sugar reduction in the basic guidelines for school meals, respectively. Approximately 95% of them had not received any sugar reduction nutrition education, and 90% were not interested in sugar reduction. The perception for sugar reduction was significantly higher in girls (3.43 out of 5 points) than in boys (3.16 out of 5 points) (P < 0.001). Knowledge about sugar was 3.65 out of 6 points in girls and 3.04 points in boys (P < 0.001). The preference and intake frequency for fruits of the total students were 4.24 out of 5 points and 2.56, respectively. For beverages, the preference was significantly higher in boys (3.97 points) than in girls (3.70 points) (P < 0.001), and the intake frequency was significantly higher in boys (2.26 points) than in girls (2.08 points) (P < 0.001). The preference for snacks was significantly higher for girls (4.19 points) than boys (4.02 points) (P < 0.01), and the intake frequency was 2.22 points in boys and 2.17 in girls, showing no significant difference. Sugar reduction perception and knowledge about sugar showed significant negative correlations with the snack intake frequency (r = -0.11, P < 0.05; -0.13, P < 0.05) after adjusting for gender, grade, and body mass index. Conclusions: The high school students' perception of sugar reduction was very low, and there was a significant correlation with sugary food intake, suggesting that the sugary food intake will decrease as the sugar reduction perception and knowledge about sugar increase.