• Atmosphere
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• v.26 no.3
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• pp.483-492
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• 2016

We have examined the random error of eddy covariance (EC) measurements on the basis of two-tower approach during daytime. Two EC towers were placed on the grassland with different vegetation density near Gumi-weir. We calculated the random error using three different methods. The first method (M1) is two-tower method suggested by Hollinger and Richardson (2005) where random error is based on differences between simultaneous flux measurements from two towers in very similar environmental conditions. The second one (M2) is suggested by Kessomkiat et al. (2013), which is extended procedure to estimate random error of EC data for two towers in more heterogeneous environmental conditions. They removed systematic flux difference due to the energy balance deficit and evaporative fraction difference between two sites before determining the random error of fluxes using M1 method. Here, we introduce the third method (M3) where we additionally removed systematic flux difference due to available energy difference between two sites. Compared to M1 and M2 methods, application of M3 method results in more symmetric random error distribution. The magnitude of estimated random error is smallest when using M3 method because application of M3 method results in the least systematic flux difference between two sites among three methods. An empirical formula of random error is developed as a function of flux magnitude, wind speed and measurement height for use in single tower sites near Nakdong River. This study suggests that correcting available energy difference between two sites is also required for calculating the random error of EC data from two towers at heterogeneous site where vegetation density is low.

• The Journal of Korean Physical Therapy
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• v.15 no.4
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• pp.151-179
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• 2003

The purpose of this study was to examine the influence of total knee replacement to arthritis patients in pain intensity and functional impairment. For this study, over 50-year-old 30 patients who had osteoarthritis and 69 patients who got total knee replacement at the one of the departments of orthopedics in Daegu were interviewed from June, 2002 to March, 2003. The results of this study were as follows : First, pain intensity was decreased to experimental group after operation than control group(P<.01) And the presence of crepitation was also decreased to them(P<.05). On the other hand there's no significant difference was noted in the presence of stiffness, degree of flexion contracture and extension contracture between two groups. Second, over 91 days group after operation and visitor's group of physiotherapy unit were better than others in Level of knee function(P<.01). Third, over 91 days group after operation and visitor's group of physiotherapy unit were higher than others in Barthel Index of knee function(P<.01). Forth, over 91 days group after operation and visitor's group of physiotherapy unit were higher than others in Level of IADL(P<.05). Fifth, over 91 days group after operation and visitor‘s group of physiotherapy unit were higher than others in Katz Index of knee function(P<.01). Sixth, although Old Ages' Activity Index seemed to get better as time goes by, there's no statistical difference. Seventh, over 91 days group after operation and visitor's group of physiotherapy unit were higher than admission group and under 30 days group after operation in Social Activity Index(P<.05). Eighth, the function of the knee was connected with the abilities in the activity of the old and the social skill. The Barthel index was connected with the function of the knee joint and the activities of the old and Katz index. IADL function was connected with the activities of the old and the social activity. The Katz index was connected with the Barthel index. The activity of the old was connected with the Barthel index, the functional score of the knee joint andthe IADL score. The ability of social skill was connected with the activity of the old, IADL score and the function of the knee.

• Journal of Korean Elementary Science Education
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• v.36 no.4
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• pp.428-438
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• 2017

The purpose of this study is to analyze the visual attention of elementary school students according to the editorial design of the 2007 2009 revised elementary science textbook 'Structure and function of our body'. For this purpose, eye movements were collected while elementary school students were watching real textbooks wearing mobile eye tracker. The BeGaze 3.7 program of SMI company was used analyzing eye movements. Twenty-six elementary school students participated voluntarily in mobile tracking research. Elementary students learned the contents of textbook related to 'digestive organ' and 'respiratory organ' by using double reading learning strategy. The results of this study are as follows. First, as a result of pre- and post-knowledge tests, there was no statistically significant difference in learning effect between 2007 revised and 2009 revised textbook editing design. Second, elementary school students tended to give more visual attention to text than textbook illustrations. Third, the selective attention and persistent attention of elementary students showed a very strong positive correlation (.940), but the selective attention and self-control showed a strong positive correlation (.499). Fourth, students with high level of attention and low level showed high visual occupancy in text than in illustrations. Fifth, elementary school students preferred the 2009 revised science textbook to the 2007 revised.

• The Korean Journal of Physiology and Pharmacology
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• v.10 no.3
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• pp.137-141
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• 2006

The systolic and diastolic pressures in anesthetized Sprague-Dawley male rats were greatly decreased after single-dose of Cd treatment without significant changes in heart rate. There was a fluid-shift into the third space and/or -loss through the kidney, since plasma $Na^+$ concentration and hematocrit ratio were significantly increased by acute Cd exposure. The present study showed that the sustained hypotensive effect of single-dose Cd on the cardiovascular system might have resulted from the systemic hypovolemia. Furthermore, renal excretion of electrolytes, including $Na^+$ and $K^+$, and urine flow rate were increased by Cd intoxication. Interestingly, the ratio of $Na^+/K^+$ excretion was increased and reached the maximum level 3 hours after Cd injection and returned to the normal level after 7 hours. Nevertheless, there was no difference in the regression analysis of $Na^+$ excretion and urine flow rate in both groups. Therefore, the increase in the urine volume seemed to enhance the excretion of $Na^+$. This study strongly suggest that the hypotensive effect of Cd is mediated by systemic $Na^+$ loss through the kidney and/or hypovolemia via fluid-shift.

• Human Ecology Research
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• v.53 no.2
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• pp.219-228
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• 2015

This study evaluated the content of Korean vocabulary learning applications with a focus on tablet PC applications. We analyzed 51 Korean vocabulary learning applications. The instruments in this study were developed based on Yoo et al. (2012)' Vocabulary Learning Game Application Evaluation Criteria and Hyun et al. (2013)' Educational Application Evaluation Criteria. Data were analyzed using a t-test and one-way analysis of variance. The main results are as follows. First, each criteria's score was fairly good; the ease of use had the highest scores and the amusement had the lowest scores. Second, there was a significant difference in the interaction by vocabulary teaching approach. Applications based on a whole language-teaching method had higher scores than applications based on a phonics instructional teaching method inducing more operation and with immediate feedback. Third, there was significant difference in the sum of score and each criteria of developmental appropriateness, educational values, amusement, function and interaction by type of learning. Applications of combining type had higher scores in every criteria except for ease of use than applications of description type. These findings provide a preliminary evidence that the systematic Korean vocabulary learning application facilitates preschoolers' vocabulary learning.

• Korean Journal of Child Studies
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• v.34 no.2
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• pp.139-160
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• 2013

The purpose of this study was to examine the difference in perception among parents of preschoolers, parents of school aged children, teachers of child care centers and elementary school teachers regarding testing on the level of preparation for attending elementary school. Firstly, the results of the study revealed that elementary school teachers had notions regarding the level of preparation for entering school that were more specific than day care teachers and parents. Second, it was shown that effort and a sense of responsibility were most important for the improvement of the level of preparation for elementary school level studies. Third, the results of this study revealed that many respondents thought that there needs to be some form of testing of the level of preparation for school and the respondents further stated that this testing needed to be conducted by child care center teachers or experts in the field. Finally, it was shown that such a test of the level of preparation for school attendance should be developed by including questions on different areas of the intelligence, adaptability, function, tendencies and regulations in relation to the needs of preschoolers.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.6
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• pp.88-98
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• 2014

A moving mass on a skewed linear guideway model to analyze the friction-induced stick-slip behavior of ball-screw-driven slides is proposed. To describe the friction force, a friction coefficient function is modelled as a third-order polynomial of the relative velocity between the slide mass and a guideway. A nonlinear differential equation of motion is derived and an approximate solution is obtained using a perturbation method for the amplitudes and base frequencies of both pure-slip and stick-slip oscillations. The results are presented with time responses, phase plots, and amplitude plots, which are compared adequately with those obtained by Runge Kutta 4th-order numerical integration, as long as the difference between the static and kinematic friction coefficients is small. However, errors in the results by the approximate solution increase and are not negligible if the difference between the friction coefficients exceeds approximately 40% of the static friction coefficient.

• Journal of the Korea Convergence Society
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• v.8 no.12
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• pp.431-444
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• 2017

The purpose of this study was to examine the difference of cognitive function, depression, and quality of life according to demographic factors and exercise participation among 148 elderly over 60 years old. The cognitive function was measured by the Korean version of mini mental state exam, Digit span test, Trail making test, and the Stroop test. Also the psychological variables were showed depression and quality of life. As a results, first, depending on the degree of demographic characteristics of elderly had significant difference. Second, according to the participation of the exercise, the score was higher than the aged who did not participate in the exercise. Third, there were significant differences according to duration of exercise, period of exercise, frequency of exercise, and exercise time of the aged that who participate in exercise. Lastly, the cognitive function, depression and quality of life of the subjects were found to be correlated. In conclusion, the aged need to regularly participate in various exercise and physical activity programs to improve the quality of life by improving the cognitive function and decreasing depression of the elderly.

• Journal of the korean Society of Automotive Engineers
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• v.14 no.2
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• pp.54-64
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• 1992

During combustion process in a diesel engine radiation heat transfer is the same order of magnitude as the convection heat transfer. An approximation of heat and momentum source distributions is applied at a level consistent with those used in modelling the soot distribution and the turbulence instead of modelling the fuel spray and the chemical kinetics. This paper illustrates a use of the third order spherical harmonics approximation to the radiative transfer equation and delta-Eddington approximation to the scattering phase function for droplets in the flow. Results are obtained numerically by a time marching finite difference scheme. This study aims to compare heat transfer with convection heat transfer and to investigate the importance of scattering by fuel droplets and of accounting for spatial variations in the extinction coefficient on the radiative heat flux distributions at the walls of a disc shaped diesel engine.

• Hwankyungkyoyuk
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• v.23 no.3
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• pp.126-139
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• 2010

The purpose of this study was to investigate the perception of designating the environmental education center for researcher, teacher, professor, NGOs. The questionnaire was composed of the introduction of designation, human resources, function, operation, facilities and 131 participated in this survey. According to the results of the study, First, environmental education center is divided into four types(national, municipal A, municipal B, private environmental education center). Second, according to the type, It is necessary to put the difference in each center. Third, the majors and career about environmental education are needed for staff.