• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.35 no.1
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• pp.55-62
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• 2017

The SRP (Solar Radiation Pressure) model has always been an issue in the dynamic GPS (Global Positioning System) orbit determination. The widely used CODE (Center for Orbit Determination in Europe) model and its variants have nine parameters to estimate the solar radiation pressure from the Sun and to absorb the remaining forces. However, these parameters show a very high correlation with each other and, therefore, only several of them are estimated at most of the IGS (International GNSS Service) analysis centers. In this study, we attempted to numerically verify the correlation between the parameters. For this purpose, a bi-directional, multi-step numerical integrator was developed. The correlation between the SRP parameters was analyzed in terms of post-fit residuals of the orbit. The integrated orbit was fitted to the IGS final orbit as external observations. On top of the parametric analysis of the SRP parameters, we also verified the capabilities of orbit prediction at later time epochs. As a secondary criterion for orbit quality, the positional discontinuity of the daily arcs was also analyzed. The resulting post-fit RMSE (Root-Mean-Squared Error) shows a level of 4.8 mm on average and there is no significant difference between block types. Since the once-per-revolution parameters in the Y-axis are highly correlated with those in the B-axis, the periodic terms in the D- and Y-axis are constrained to zero in order to resolve the correlations. The 6-hr predicted orbit based on the previous day yields about 3 cm or less compared to the IGS final orbit for a week, and reaches up to 6 cm for 24 hours (except for one day). The mean positional discontinuity at the boundary of two 1-day arcs is on the level of 1.4 cm for all non-eclipsing satellites. The developed orbit integrator shows a high performance in statistics of RMSE and positional discontinuity, as well as the separations of the dynamic parameters. In further research, additional verification of the reference frame for the estimated orbit using SLR is necessary to confirm the consistency of the orbit frames.

• Research in Community and Public Health Nursing
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• v.14 no.4
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• pp.657-666
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• 2003

Purpose; This study was conducted to investigate the relationship between self-efficacy, family support and health promotion behavior of the elderly in a community. Method: The sample consisted of 208 elderly and data was collected from November 18 to December 21, 2002. The instrument of this study was a structured questionnaire including health promoting behaviors, self-efficacy, family support, general characteristics. Analysis of the data was done by use of descriptive statistics, t or F, Pearson Correlation Coefficient, Stepwise multiple regression. Results: 1. The general characteristics related to health promoting behavior were gender, family structure, education level and monthly pocket money. 2. The general characteristics related to self efficacy were gender, age, family structure, education level, religion and monthly pocket money. 3. The general characteristics did not affect family support. 4. Health promoting behavior score was the highest in the interpersonal support (2.72) and in order was nutrition(2.65), stress management(2.31), self actualization(2.30), exercise(2.05), health responsibility(1.86). 5. There was a significantly high correlation between health promoting behavior and self efficacy(r= .605, p= .000), and family support(r= .500, p= .000) and between self-efficacy and family support were correlated relatively high(r= .498, p= .000) 6. Stepwise multiple regression analysis revealed that the most powerful predictor of health promotion behavior in elderly was self-efficacy (39.6%). A combination of self-efficacy, family support, monthly pocket money, education level and present illness status explained 48.5% of the variance for health promoting behavior. In conclusion, the results of this study showed that self-efficacy and family support are very important variables in explaining the health promoting behaviors in elderly. Therefore, these variables should be considered in nursing intervention development and education, especially, self-efficacy improving programs that considered exercise and health responsibility are expected to effect the health promoting behavior in elderly.

• Journal of the Korean Society of Systems Engineering
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• v.11 no.2
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• pp.61-73
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• 2015

The early-phase naval ship design demands requirements synthesis rather than design synthesis, which conducts engineering design for several domains on a detailed level. Requirements synthesis focuses on creating a balanced set of required operational capabilities satisfying user's needs and concept of operations. Requirements are evolved from capability based languages to function based language by statistical exploration and engineering design which are derived in the following order: concept alternative, concept baseline, initial baseline and functional baseline. The early-phase naval ship design process can be divided into three passes: concept definition, concept exploration and concept development. Main activities and outcomes in each pass are shortly presented. Concept definition is the first important step that produces a concept baseline through extensive design space exploration promptly. Design space exploration applies a statistical approach to explore design trends of existing ships and produce feasible design range corresponding to concept alternative. It further helps naval systems engineers and operational researchers by inducing useful responses to user and stakeholders' questions at a sufficient degree of confidence and success in the very early ship design. The focus of this paper is on the flow of design space exploration, and its application to a high-speed patrol craft. The views expressed in this paper are those of the authors, and do not reflect the official policy or rule of the Navy.

• Child Health Nursing Research
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• v.20 no.4
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• pp.332-339
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• 2014

Purpose: This descriptive correlational study was designed to examine the relationship of perfectionism to anger thought and problem behaviors. In addition, the mediating effect of anger thought in relation to perfectionism and problem behaviors was investigated. Methods: Data were collected from 807 students in a girls' high school, and descriptive statistics, t-test, ANOVA, and hierachical multiple regression were used with SPSS/PC 18.0 program to analyze the data. Results: There were significant differences in anger thought (primary and secondary anger-thought) and problem behaviors between the upper 25% and lower 25% group for perfectionism. Primary and secondary anger-thought had a significant mediating effect in relation to perfectionism and problem behaviors. Conclusion: For effective management and prevention of adolescent women's problem behaviors, programs including perfectionism and anger thought should be developed. Further research is necessary in order to draw a consensus on cognitive factors as mediators between the related factors of problem behaviors.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.61.1-61.1
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• 2017

As the application of deep-learning methods has been succeeded in various fields, they have a high potential to be applied to space weather forecasting. Convolutional neural network, one of deep learning methods, is specialized in image recognition. In this study, we apply the AlexNet architecture, which is a winner of Imagenet Large Scale Virtual Recognition Challenge (ILSVRC) 2012, to the forecast of daily solar flare occurrence using the MatConvNet software of MATLAB. Our input images are SOHO/MDI, EIT $195{\AA}$, and $304{\AA}$ from January 1996 to December 2010, and output ones are yes or no of flare occurrence. We consider other input images which consist of last two images and their difference image. We select training dataset from Jan 1996 to Dec 2000 and from Jan 2003 to Dec 2008. Testing dataset is chosen from Jan 2001 to Dec 2002 and from Jan 2009 to Dec 2010 in order to consider the solar cycle effect. In training dataset, we randomly select one fifth of training data for validation dataset to avoid the over-fitting problem. Our model successfully forecasts the flare occurrence with about 0.90 probability of detection (POD) for common flares (C-, M-, and X-class). While POD of major flares (M- and X-class) forecasting is 0.96, false alarm rate (FAR) also scores relatively high(0.60). We also present several statistical parameters such as critical success index (CSI) and true skill statistics (TSS). All statistical parameters do not strongly depend on the number of input data sets. Our model can immediately be applied to automatic forecasting service when image data are available.

• Journal of Korean Clinical Nursing Research
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• v.22 no.1
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• pp.28-37
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• 2016

Purpose: This study was to investigate the relationships between among health literacy, knowledge and self-care behavior in elderly patients with heart failure(HF). Methods: 166 patients (age ${\geq}65$ years) with HF were recruited in a cardiovascular center of an university affiliated hospital. The structured questionnaire included Health literacy, Dutch Heart Failure Knowledge Scale, European Heart Failure Self-care Behavior, Self-Care of Heart Failure Index. Data were analyzed by descriptive statistics, Chi-test, Pearson correlation analysis, t-test and ANCOVA using SPSS/WIN version 21.0. Results: Participants with the high level of health literacy were more likely to be younger (p=.001), men (p=.001), with more education (p<.001), and have a job (p=.004), and with a higher economic status (p=.005). The positive correlations between the level of health literacy, knowledge, and self-care behavior were confirmed (p<.001). Participants with the high level of health literacy showed higher level of knowledge, more self-care behavior for health maintenance, and confidence. Conclusion: This study shows that the level of health literacy may influence knowledge and self-care behavior in elderly patients with HF. In order to improve self-care behaviors in elderly patients, a strategic nursing approach based on the level of patients' health literacy needs to be considered.

• Research in Community and Public Health Nursing
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• v.15 no.2
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• pp.237-245
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• 2004

Purpose: This study was to identify the relationships among the depression, social support and quality of life of the elderly in rural areas. Method: The subjects of this study were 199 people aged over 60 who had been living in three rural area. Data were collected through a questionnaire survey from the 10th of July to the 10th of August 2003. Collected data were analyzed using descriptive statistics, t-test, ANOVA. Duncan's multiple-range test, Pearson's correlation coefficient and multiple stepwise regression with SPSS & SAS. Result: The average depression score was 11.09. As for the score of social support by supporter, the score of spouse' support was 13.36 out of 18 points, children's support 13.27, friends' support 11.40, neighbors' support 10.21 and siblings' support 10.20. The average score of quality of life was 132.26 out of 220 points. As for the score of the sub-areas of quality of life, the score was highest in economic status(32.18) and lowest in neighbor relationship (16.42). The score of quality of life was negatively correlated with the score of depression (r=-.014) and positively with the score of social support (r=.338). The suitable regression from the results of the multiple regression analysis to investigate factors influencing quality of life was expressed by y=58.341-$0.361x_1$+$1.492x_2$ ($x_1$: social support, $x_2$: depression) and $R^2$=.327. Conclusion: These results suggest that elderly people in rural areas with high quality of life is likely to be low in depression and high in social support. Therefore, it is necessary to develop health promotion programs in due consideration of depression and social support in order to enhance the quality of life of elderly people in rural areas.

• Journal of the Korean School Mathematics Society
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• v.17 no.4
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• pp.629-656
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• 2014

This study developed teaching and learning materials for an integrated education program of probability and genetics in the light of connections between mathematics and biological science. It also analysed characteristics of high school students' mathematical activities which appeared while the students took part in lessons where the developed materials were contributed in order to teach them. To achieve the aim, this study firstly specified five details for the development of the materials based on the results of previous research and extracted contents of probability and genetics which had the possibility of being taught in the integrated education program by examining the text books. After embodying the teaching materials according to the five details and the extracted contents, the researchers implemented 10 lessons by using the materials. This study elaborated some implications for a succeeding integrated education of mathematics and biological science in term of anlaysis results of features from the students' mathematical understanding and attitudes emerging in the lessons.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.5
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• pp.812-820
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• 2006

Ethernet has been given a greater attention recently due to tendency of unifying most of transmission technique(not only LAN, but MAN and WAN) to ethernet. Performance evaluation was performed using C language for 10Gbps ethernet Data Link to design the optimum hardware, then internal FIFO size was evaluated. In this paper, MAC core for 10Gbps ethernet which contains high layer interface, transmit engine, flow control block, receive engine, reconciliation sublayer, configuration block, statistics block, and XGMII interface block was designed using VHDL language and Xilinx 6.2i tool and verified using Model_SIM 5.7G simulator. According to the specification of 10Gbps ethernet, MAC core with 64-bit data path should support 156.25MHz in order to support 10Gbps. The designed MAC core that process 64-bit data, operates at 168.549MHz and hence supports the maximum 10.78Gbps data processing. The designed MAC core is applicable to an area that needs a high-speed data processing of 10Gbps or more.

• Journal of Preventive Medicine and Public Health
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• v.43 no.5
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• pp.396-402
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• 2010

Objectives: Self-reported anthropometric values, such as height and weight, are used to calculate body mass index (BMI) and assess the prevalence of obesity among adolescents. The aim of this study was to evaluate the validity of selfreported height, weight, and BMI of the Korea Youth Risk Behavior Web-based Survey questionnaire. Methods: A convenience sample of 137 middle school students and 242 high school students completed a selfadministered questionnaire in 2008. Body height and weight were directly measured after self-reported values were obtained from the questionnaire survey. Sensitivity, specificity, and kappa statistics were computed in order to evaluate the validity of the prevalence of obesity (BMI $\geq$ 95th percentile or $\geq$ $25;kg/$m^2$) based on self-reported data. Results: Self-reported weight and BMI tended to be underestimated. Self-reported height tended to be overestimated among middle school females and high school males. Obese adolescents tended to underestimate their weight and BMI and overestimate their height more than non-obese adolescents. The prevalence estimate of obesity based on selfreported data (10.6%) was lower than that based on directly measured data (15.3%). The estimated sensitivity of obesity based on self-reported data was 69.0% and the specificity was 100.0%. The value of kappa was 0.79 (95% confidence interval, 0.70 - 0.88). Conclusions: This study demonstrated that self-reported height and weight may lead to the underestimation of BMI and consequently the prevalence of obesity. These biases should be taken into account when self-reported data are used for monitoring the prevalence and trends of obesity among adolescents nationwide.