• Journal of Korean Association for Spatial Structures
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• v.1 no.1 s.1
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• pp.117-124
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• 2001

In Single-layer latticed domes with rectangular network which is composed of ring of circumferential direction and rafter of longitudinal direction, that is, rib domes, if we use the cross-membered junction's method for the advantage in fabrication and construction, the eccentricity is occurred in the nodal point of crossing members. This paper is aimed at investigating the buckling characteristics for the effect of eccentricity according to rise-span ratios and distance of eccentricity. Analysis method is based on FEM dealing with the geometrically nonlinear deflection problems. The conclusion were given as follows: 1. The maximum decreasing ratio of buckling strength due to the junction's eccentricity is about 60% in models of this paper. 2. In the increasing ratio of buckling strength for rise-span ratio, that of Type 3 models is larger than that of type 2 models. On the other hand, that of Type 2 mode is larger than that of Type 3 for eccentricity-distance. 3. In the viewpoint of the value of buckling strength, that of Type 2 models is larger than that of type 3 models. The effect of the junction's rigidity on buckling strength is not great for overall models. Therefore if we use the cross-membered junction's method for the advantage in fabrication and construction, the method of Type 2 will have the great advantage of that of Type 3.

• 대한예방의학회:학술대회논문집
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• 1994.02b
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• pp.137-141
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• 1994

The purpose of this paper is to examine what is meant by a ralid measure of health. Guyatt, Kirshner and Jaeschke propose that health tests should be designed so as to have one of several kinds of validity: 'longitudinal construct validity' for those which are used for longitudinal research designs, and 'cross-sectional construct validity' for those which are used for cross-sectional designs. Williams and Naylor argue that this approach to test classification and validation confuses what a test purports to measure with the purpose for which it is used, and that some tests have multiple uses. A review of the meanings of validity in the psychologica test literature shows that both sets of authors use the term validity in an idiosyncratic way. Although the use of a test (evaluated by content validity) should not be conflated with whether the test actually measures a specified construct (evaluated by construct validity);' if health is actually made up of several constructs (as suggested in Hyland's interactional model) then there may be an association between types of construct and types of purpose. Evidence is reviewed that people make several, independent judgements about their health: cognitive perceptions of health problems are likely to be more sensitive to change in a longitudinal research design. whereas emotional evaluations of health provide less bias in cross-sectional designs. Thus. a classification of health measures in terms of the purpose of the test may parallel a classification in terms of what tests purport to measure.

• Research in Mathematical Education
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• v.26 no.2
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• pp.63-82
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• 2023

In the context of Korean educational research, the number of qualitative research studies has gradually increased since 2000. It has become one of the most important research methods today. The field of math education is no exception to this trend, and qualitative approaches are now becoming one of the main research methods. This increase in qualitative research has contributed to the provision of detailed information about educational practice, but at the same time, the overall level of credibility in the results of qualitative research seems to be lower than that of quantitative research. This study started with the problem consciousness that the number of qualitative studies is increasing in the field of mathematical education, but there is a lack of discussion on the methodology of applying qualitative research methods. In this study, among the papers published in the journal related to mathematical education, papers using a qualitative approach are analyzed focusing on cross-case analysis. Based on the analysis results, the tendency to use qualitative approaches is diagnosed, ways of improving the validity and trustworthiness of qualitative research results in the field of mathematical education are examined, and implications and suggestions are presented.

• Iberoamérica
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• v.12 no.1
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• pp.407-439
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• 2010

Growth of researches addressing cross-culture in international business is exponential. This article reviews the extant researches around the national culture and describes the various conceptualization of culture through discussion of some of popular models of national culture. This article presented some of the most important issues in international business surrounding globalization, especially convergence and divergence of cultures and cultural changes. Global rapid changes in international business environment request the reconsideration of the assumption of cultural stability and the simple view of culture, which tends to examine the static influence of a few cultural factors in isolation form other cultural factors and contextual elements. This paper identifies a valid cultural grouping and proposes the following typology of the possible methodologies in international business; Ethnological description, Use of proxies, Direct values inference, and Indirect values inference. Rather than selecting a single methodology, it appears to be more appropriate to use multi-method in the cross-cultural international business research. It has been shown that cultural change is intertwined with socioeconomic-institutional variables, and that these variables may also add to determine culture contemporarily. This paper also explained the dynamics of culture as multi-level, multi-layer constructs. According to this model, we may understand how the dynamic nature of culture conveys the top-down-bottom-up processes where one cultural level affects changes in other level of culture.

• Journal of Chest Surgery
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• v.18 no.4
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• pp.759-770
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• 1985

This study was experimentally undertaken to evaluate the effect of hypothermic oxygenated cardioplegic solution on myocardial protection during prolonged aortic cross clamping under cardiopulmonary bypass. Dogs were divided into two groups control group [received hypothermic unoxygenated cardioplegic solution] and experimental group [received hypothermic oxygenated cardioplegic solution]. Coronary sinus effluent was obtained at once and 30, 60, 90 minutes after cross-clamping for the determination of pH, PCO2,PO2 and lactate level during the infusion of cardioplegic solution and myocardial biopsies were obtained after cessation of 90 minutes of aortic cross-clamping. The results obtained were as follows: 1. There was no significant differences in the pH and PCO2 between the oxygenated and unoxygenated cardioplegic solution but the PO2 of the oxygenated solution was 4 times greater than unoxygenated solution, and also the oxygenated solution had a significantly greater oxygen content [2.020.05 ml 02/min] and had much more oxygen delivery than unoxygenated solution. 2. The myocardial oxygen consumption and the myocardial oxygen extraction in oxygenated group were 1.63 ml 02/100 ml and 67.32% respectively, which was greater than those in unoxygenated group. 3. Regarding to pH and PCO2 of coronary sinus effluent, there was no significant differences between two groups in early period of infusion of cardioplegic solution, but the pH shifted to acidosis from 60 minutes, PCO2 increased from 90 minutes of aortic cross-clamping, and PO2 markedly decreased from 90 minutes of aortic cross-clamping in unoxygenated group. 4. The lactate concentration of coronary sinus effluent revealed relatively normal in both groups, but showed slight increase up to 27.54.56 mg/100 ml at 90 minutes of aortic cross-clamping in unoxygenated group. 5. On electron microscopic study, the ultrastructural integrity of myocardial cells in oxygenated group was well preserved within 90 minutes. Slight swelling and deformity of mitochondria, interfibrillar widening, and disarrangement of myofibrils were observed at 90 minutes after aortic cross-clamping in unoxygenated group. From these results, the use of hypothermic oxygenated cardioplegic solution seemed to be effective and better method for the preservation of ischemic myocardium during the prolonged aortic cross-clamping.

• Nutritional Sciences
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• v.4 no.2
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• pp.104-111
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• 2001

The Purpose of this study was to investigate the dietary intake of nutrients and the use of vitamin and mineral supplements by Korean college students attending Web class and the socioeconomic, dietary and health-related factors involved. The subjects were 137 male and 115 female students amending a health and nutrition-related Web class at a cycler university. This cross-sectional survey was conducted by self-administered questionnaire and the data were analyzed by SAS and SPSS PC package programs. Nutrient intake data collected using three-day recall method were analyzed by the Computer Aided Nutritional Analysis Program. Average intake by male students of most nutrients except energy, vitamin B$_2$ and calcium and intake by female students of those except energy, vitamin $B_2$, calcium and iron was higher than Korean RDA. Nutrient intake of male students was significantly influenced by the mother s job, skipping meals, exercise, vitamin and mineral supplement use, flood supplement use and self-evaluated anemia. Skipping meals and flood supplement use significantly influenced the nutrient intake of female students. A total of 47.4% of male students and 53.9% of female students were vitamin and mineral supplement users. In female students, socioeconomic characteristics such as the father s education level and household income were significantly different between vitamin and mineral supplement users and non-users. In both male and female students, there were significant differences in cross analysis between vitamin and mineral supplement use and flood supplement use. As for the self-reported health status of male and female students, vitamin and mineral supplement users perceived their health status to be worse compared to non-users. Therefore, nutrition education via the Internet is necessary in order to encourage college students to practice optimal nutrition strategies, including maintaining well-balanced diets by choosing various floods wisely.

• Journal of the Korean Society of School Health
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• v.29 no.3
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• pp.180-188
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• 2016

Purpose: The purpose of this study was to identify the correlation between the motivations to use social media and self-control among female middle school students. Methods: This study is a cross-sectional descriptive study. To collect the data, 300 female students of S and E middle school in S city responded to a self-administered questionnaire asking about their motivation for social media use and self-control. The data were analyzed through descriptive statistics, independent t-test, one way ANOVA, Scheffétest, Pearson's correlation, and stepwise multiple regression, using the SPSS/WIN 21.0 program. Results: The average time spent on social media was 3.70 hours. The mean scores of social media usage motivation and self-control were 48.15 and 58.47, respectively. The more average time spent on social media, the higher was the motivation to use social media. The scores of motivation to use social media were higher in students with low satisfaction of their school and family life. Students with low satisfaction of their school life had higher scores in some subcategories of self-control; preference to simple task, egocentrism, and stroppiness. Motivations to use social media showed a significant positive correlation with self-control. Self-control was affected by motivations to use social media and this variable explained 11.6% of self-control among female middle school students. Conclusion: The results of this study suggest that we should develop programs which help improve students' self-control and prevent the side effects of social media use among female middle school students.

• Journal of Biomedical Engineering Research
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• v.9 no.2
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• pp.251-252
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• 1988

To develop an artificial bone substitute that is gradually degraded and replaced by the regenerated natural bone, the authors designed a composite that is consisted of calcium phosphate and collagen. To use as the structural matrix of the composite, collagen was purified from human umbilical cord. The obtained collagen was treated by pepsin to remove telopeptides, and finally, the immune-free atelocollagen was produced: The cross linked atelocollagen was highly resistant to the collagenase induced collagenolysis. The cross linked collagen demonstrated an improved tensile strength.

• Journal of the Korean Data and Information Science Society
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• v.22 no.3
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• pp.613-618
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• 2011

The proposed method is based on a penalized log partial likelihood of Cox proportional hazard model with L1-penalty. We use the iteratively reweighted least squares procedure to solve L1 penalized log partial likelihood function of Cox proportional hazard model. It provide the ecient computation including variable selection and leads to the generalized cross validation function for the model selection. Experimental results are then presented to indicate the performance of the proposed procedure.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.04a
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• pp.133-138
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• 2000

In this paper some shapes of the FBW cross sections were examined to improve the performance of FBW for the long wave. Trapezoidal section and prominence section were examined. Linear potential theory is used and the boundary element method is use for numerical computation. Proper choice of the pontoon geometry may improve the transmission coefficient in the long wave range for a given wave period.