• Journal of Korea Water Resources Association
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• v.41 no.8
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• pp.807-823
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• 2008

This paper presents a technique for estimating discharge rating curve parameters. In typical practical applications, the original non-linear rating curve is transformed into a simple linear regression model by log-transforming the measurement without examining the effect of log transformation. The model of pseudo-likelihood estimation is developed in this study to deal with heteroscedasticity of residuals in the original non-linear model. The parameters of rating curves and variance functions of errors are simultaneously estimated by the pseudo-likelihood estimation(P-LE) method. Simulated annealing, a global optimization technique, is adapted to minimize the log likelihood of the weighted residuals. The P-LE model was then applied to a hypothetical site where stage-discharge data were generated by incorporating various errors. Results of the P-LE model show reduced error values and narrower confidence intervals than those of the common log-transform linear least squares(LT-LR) model. Also, the limit of water levels for segmentation of discharge rating curve is estimated in the process of P-LE using the Heaviside function. Finally, model performance of the conventional log-transformed linear regression and the developed model, P-LE are computed and compared. After statistical simulation, the developed method is then applied to the real data sets from 5 gauge stations in the Geum River basin. It can be suggested that this developed strategy is applied to real sites to successfully determine weights taking into account error distributions from the observed discharge data.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.242-247
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• 2017

The foster care system is a social welfare service that supplements the functions of the family while enabling children, who cannot receive proper care from their biological parents, to receive the necessary protection under the plan within the prescribed period of time within a substitute or foster family. A large part of the emotional instability experienced by foster care children is interpersonal maladjustment. Low self-esteem leads to difficulty in forming social relationships due to negative interpersonal relationships. Thus, the purpose of this study is to investigate the effects of traditional dance programs on the foster children who live in Daejeon Metropolitan City. A comparison between the pre- and post-interpersonal scores showed that the scores were improved after the traditional dance program, and the children's intimacy formation and communication were also improved. The participants were less active at the beginning of the program, but became more interested and more active toward the middle of the program. The majority of the participants increased their degree of communication with the formation of intimacy toward the middle of the program, and their self-confidence improved in terms of their peer relationships. The purpose of this study was to investigate the effects of traditional dancing on the development of interpersonal relationships. In a subsequent study, a traditional dancing program consisting of various contents will be applied over a long period of time, which should provide them with the opportunity to improve their interpersonal skills. In addition, it is necessary to provide educational opportunities for helping foster children reduce their emotional instability with systemic and diverse traditional dance programs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.30-41
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• 2018

This phenomenological study aims to explore Nursing Students' Experiences who have experienced team-based learning (TBL). The purpose of this study is to contribute to fostering professional nurses required in the clinical field by improving the learning outcomes by applying the TBL classes. The study participants were seven students of the nursing department who took TBL classes in adult nursing classes. The data were collected through participating observations and in-depth interviews, and analyzed using Colaizzi's phenomenological methods. As a result of the study, nine conceptual descriptions and five theme clusters were derived. The major theme clusters for the experiences of students were 'Dedication to best results', 'Self-led learning attitudes are formed', 'Becoming a communal knowledge creator', 'Active class time', and 'Meaningless peer evaluation'. Nine conceptual descriptions were 'Doing one's best to fulfill one's role', 'Preparing for the class with the pre-learning', 'Forming confidence through pre-learning', 'Solving problems through interaction with friends', 'Becoming a mentor to each other', 'Working together to resolve issues', 'Intimacy formed', 'A lively class', and 'Peer evaluation with familiarity'. This study contributes to the improvement of the learning outcomes of the nursing students by enabling learner-centered classes and self-led learning, thereby contributing to fostering the professional nursing manpower required in the clinical field.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.362-373
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• 2018

This study was pre-experimental research designed to compare the differences between pre-and post the effect of core fundamental education program of senior nursing student′s core fundamental nursing skills, clinical competency and problem solving process for one semester. Core fundamental education program which consists of three steps, 12 session. The subjects of this study were 192 graduates of one nursing college and surveyed from March 20 to June 23, 2017. The data were analyzed using descriptive statistics, the paired t-test, t-test, ANOVA by SAS for Windows(ver. 9.8) and AMOS(ver. 20.0) As a result, pre-post recognition level of core fundamental education program was nursing skills competency pre $(3.42{\pm}.42)$ and post $3.88({\pm}.61)$, clinical competency was pre $3.74({\pm}.47)$ and post $3.98({\pm}.67)$. The core fundamental nursing skills(p=.017), clinical competency(p=.041) increased significantly after education program. Core fundamental nursing skills, clinical competency and problem solving process was significantly different according to male group(p=.003/p=.013/p=.005), high satisfaction group in nursing major(p=<.000/p=.009/p=<.000), confidence improvement group(p=.044/p=.047/p=.004) at the core skill contest. In conclusion, this study showed that the core fundamental nursing education program of senior nursing students had a positive effect on core fundamental nursing skills and clinical competency.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.2
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• pp.91-99
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• 2014

The common-rail injectors are the most critical component of the CRDI diesel engines that dominantly affect engine performances through high pressure injection with exact control. Thus, from now on the advanced combustion technologies for common-rail diesel injection engine require high performance fuel injectors. Accordingly, the previous studies on the numerical and experimental analysis of the diesel injector have focused on a optimum geometry to induce proper injection rate. In this study, computational predictions of performance of the diesel injector have been performed to evaluate internal flow characteristics for various needle lift and the spray pattern at the nozzle exit. To our knowledge, three-dimensional computational fluid dynamics (CFD) model of the internal flow passage of an entire injector duct including injection and return routes has never been studied. In this study, major design parameters concerning internal routes in the injector are optimized by using a CFD analysis and Response Surface Method (RSM). The computational prediction of the internal flow characteristics of the common-rail diesel injector was carried out by using STAR-CCM+7.06 code. In this work, computations were carried out under the assumption that the internal flow passage is a steady-state condition at the maximum needle lift. The design parameters are optimized by using the L16 orthogonal array and polynomial regression, local-approximation characteristics of RSM. Meanwhile, the optimum values are confirmed to be valid in 95% confidence and 5% significance level through analysis of variance (ANOVA). In addition, optimal design and prototype design were confirmed by calculating the injection quantities, resulting in the improvement of the injection performance by more than 54%.

• Korean Journal of Poultry Science
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• v.9 no.1
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• pp.17-33
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• 1982

The purpose of this experiment is to clarify the additional effect of antibiotics for the chicken breeding feed. This experiment was carried out with 6,560 individuals which were collected from four farms, Dugil, Hyubhoi, Sanggog and Kumsan. The duration of this experiment was 6 months from July to December in 1981. 1. Body weight and body gain. (1) The range of the body gain was 1.91-7.60% The most effective sections was T$_3$, and the effect was T$_2$, T$_4$, T$_1$, T$\sub$5/ in order. (2) The environmental sanitation of the Sanggog farm was not so good. In this farm the body gain was severely occurred in T$_3$ and T$_2$ sections. Mere gain obtained from T$\sub$5/ section. (3) The environmental sanitation was good in Dugil, Hyubhoi and Kumsan. A little body gain was occurred in these farms, but differences were shown according to the place or breeds. 2. Amount of feed intake feed conversion ratio. (1) Amount of feed intake was increased 0.13-3.19%, and feed conversion ratio was improved 1.68-4.62% compared with control. T$_3$ section showed high percent and T$_4$ T$_1$, T$\sub$5/, Is, C in order. (2) The keeping method of the chicken breed in Hyubhoi was floor brooding. From Hyubhoi and Sanggog farms, the efficiency was increased 9.4-9.8%. (3) From Dugil and Kumsan, the rate of improvement was low. 3. Mortality : Mortality was merely decreased in Sanggog and Kumsan farms which the sanitary and fowl caring conditions had been had, by additional antibiotics. But there was no worthy effect. 4. The ratio of carcass and the degree of skin coloration. The additional antibiotics in feed had no effect on the ratio of carcass but had the influence on the yellowish skin coloration. Skin coloring was good in T$\sub$7/ section and T$_1$, T$\sub$6/, T$_4$, C, T$_3$, T$\sub$5/, T$_2$ in order. 5. Economical efficiency (1) The addition of the antibiotics in feed increased 3.76-10.95% of gross earning. The highest earning was occurred in T$_4$ section and T$_3$, T$_1$, T$_2$, T$\sub$5/, C sections in order. (2) The earning rate was influenced by the antibiotic products. (3) In Dugil and Kumsan farms, there was no difference in earning, however, in Hyubhoi and Sanggog farms there was wide difference in earning. Conclusionally, the addition of antibiotics in chicken breeding feed is necessary. Especially in bad condition of environmental sanitation and floor brooding, the effect of additional antibiotics is clear. Selection of antibiotics from various kinds, maker's confidence and quality problems are important.

• Communications of Mathematical Education
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• v.23 no.2
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• pp.327-347
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• 2009

The purpose of the present study is to investigate the effects of mathematical communication-centered teaching using peer feedbacks on students' mathematics achievement and mathematical dispositions toward mathematics, and then this study examined the characteristics of feedbacks used by students. To do this study, two sixth grade classes selected from an elementary school in Seoul participated in the current study; one class for a treatment group applying mathematical communication-centered teaching using peer feedback, and the other for a comparison group applying traditional teaching using teacher-centered communication. The results of this study showed the fact that a treatment group of mathematical communication-centered teaching applying peer feedback scored statistically higher than a comparison group applying teacher-centered communication with respect to both students' mathematical achievement and disposition. Especially, this communication-centered teaching program focused on peer feedback was more effective to middle or lower level students than higher level students. In addition, mathematical communication-centered teaching applying peer feedbacks helps students reflect their own thinking process about problem solving, and students experienced the improvement of their confidence about mathematics from opportunities to provide peers with feedbacks. Finally, the present study suggests the important role of communication in mathematics learning, particularly student-to-student feedbacks rather than teacher-to-students feedbacks. That is to say, students need to have many opportunities to represent their own mathematical thinking processes using mathematical language.

• Journal of Preventive Medicine and Public Health
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• v.48 no.2
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• pp.94-104
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• 2015

Objectives: Mental health disorders and suicide are an important and growing public health concern in Korea. Evidence has shown that both globally and in Korea, obesity is associated with an increased risk of developing some psychiatric disorders. Therefore, we examined the association between distorted body weight perception (BWP) and suicidal ideation. Methods: Data were obtained from the 2007-2012 Korea National Health and Nutritional Evaluation Survey (KNHANES), an annual cross-sectional nationwide survey that included 14 276 men and 19 428 women. Multiple logistic regression analyses were conducted to investigate the associations between nine BWP categories, which combined body image (BI) and body mass index (BMI) categories, and suicidal ideation. Moreover, the fitness of our models was verified using the Akaike information criterion. Results: Consistent with previous studies, suicidal ideation was associated with marital status, household income, education level, and perceived health status in both genders. Only women were significantly more likely to have distorted BWP; there was no relationship among men. In category B1 (low BMI and normal BI), women (odds ratio [OR], 2.25; 95% confidence interval [CI], 1.48 to 3.42) were more likely to express suicidal ideation than women in category B2 (normal BMI and normal BI) were. Women in overweight BWP category C2 (normal BMI and fat BI) also had an increased OR for suicidal ideation (OR, 2.25; 95% CI, 1.48 to 3.42). Those in normal BWP categories were not likely to have suicidal ideation. Among women in the underweight BWP categories, only the OR for those in category A2 (normal BMI and thin BI) was significant (OR, 1.34; 95% CI, 1.13 to 1.59). Conclusions: Distorted BWP should be considered an important factor in the prevention of suicide and for the improvement of mental health among Korean adults, especially Korean women with distorted BWPs.

• Journal of the Korean Wood Science and Technology
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• v.43 no.4
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• pp.456-462
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• 2015

365 pieces of domestic $38{\times}140{\times}3600mm$ Red pine structural lumber were machine graded conforming to a softwood structural lumber standard (KS F 3020). The allowable bending stresses calculated for each grade were compared with the values currently tabulated in the standard. Four calculation methods for lower $5^{th}$ percentile bending stress were non-parametric estimation with 75% confidence level, 2-parameter and 3-parameter Weibull distribution fit, and bending modulus of rupture (MOR)-modulus of elasticity (MOE) regression based method. Only the data set of Grades E8, E9, and E10 were statistically eligible for the $5^{th}$ percentile calculation. The MOR-MOE regression based method only was able to estimate the lower $5^{th}$ percentile values theoretically for the full range of grades. The results showed that all allowable bending stresses calculated were lower than the design values tabulated in the standard. This implies that the current machine grading system has the pitfall of structural safety. Improvement in current machine grading system could be achieved by introducing the bending strength and stiffness combination grade system.

• Communications of Mathematical Education
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• v.29 no.4
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• pp.745-762
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• 2015

In order to examine the change in mathematical inclinationn of middle level engineering college freshmen, we analyse the change of mathematical inclination between 2011 year and 2015 year freshmen who took college scholastic ability test which are based on the national mathematics curriculum 7th and 7th revision, respectively. In medium-sized D university, 2011 year and 2015 year engineering freshmen were taken the test for mathematical inclination, the survey for mathematical background and the recognition of college mathematics and basic mathematical ability test. The outcomes of this survey are followings: Firstly, between 2011 year and 2015 year freshmen, the mean of confidence and flexibility are same, but the 2015's mean of willpower, curiosity, value and esthetics are greater than 2011's. Secondly, in the mean of flexibility, willpower and curiosity, natural science's mean is greater than humanity's. Thirdly, the mean of mathematical inclination's factors is depend on college mathematics goal. Fourthly, there is little correlation between mathematical basic ability and mathematical inclination. Moreover for 2011 year and 2015 year freshmen, the mean of mathematical inclination's factors except value is proportional to mathematical basic ability. For the success of college mathematics in engineering college, this study suggests that high school mathematics curriculum and college scholastic ability test must contain calculus. We also suggest that college mathematics class must be focused on mathematical inclination improvement.