• Korean Journal of Soil Science and Fertilizer
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• v.39 no.3
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• pp.144-150
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• 2006

Chemical characteristics and their interrelationships of 156 soils included by 74 sandy loam and 82 loam soils collected from plastic film house in Chungbuk area were investigated from 1998 to 2001. Seventeen chemical properties including pH, organic matter (OM), electrical conductivity (EC), inorganic nitrogen, available phosphorus, exchangeable cations, CEC, etc., were analyzed by correlation, standardized partial regression coefficient, and principal factor analysis. Standardized partial regression coefficients of chemical properties were estimated to determine the degree of contribution of EC and OM contents in soils. Principal factor analysis was applied to classify the studied chemical properties into different groups having similar chemical properties. The pH of experimental soils ranged from 4.24 to 7.14 and 4.95 to 7.35 for loam and sandy loam soils, respectively. The EC of soils varied from 0.93 to $15.65dS\;m^{-1}$ for loam and $0.91{\sim}22.30dS\;m^{-1}$ for sandy loam soils, respectively with significant differences among them. The EC measured by 1:5 $H_2O$ dilution method and saturation method were significantly related with 8.163 and 8.599 as the slopes of regression equation for loam and sandy loam soils, respectively. These slopes more than 8.0 in this regression equation was higher than the slope of 5.0 that is estimated from dilution coefficient suggesting that EC measured by 1:5 dilution method might be erratic. The standardized partial regression coefficient of different chemical properties for the estimation of EC was in the order of $NO_3{^-}$ > $Cl^-$ > OM > exchangeable Mg for loam soils and $NO_3{^-}$ > exchangeable Mg > $Cl^-$ for sandy loam soils. Contribution order of the chemical properties based on standardized partial regression coefficient differed 1:5 dilution method and saturation method, indicating that different chemical compounds might be present in the extract solutions of these two methods. Consequently the measurement of EC by saturation method was thought be still better for estimation of chemical property because accuracy of EC measurement by 1:5 dilution method can't be improved by any specific coefficient for adjustment of EC. Regardless of differences in soil textures and extraction methods, correlation coefficients between EC and the other chemical properties were routinely in the order of $NO_3{^-}$ > $Cl^-$ > degree of base saturation > exchangeable Mg > exchangeable Ca > $SO{_4}^{2-}$. The principal factor analysis revealed four factor groups of the chemical properties studied. The groups for sandy loam were as follows; ; 1. salt components, 2. soil reaction components, 3. fixed and adsorption components, 4. CEC components. The groupings of loam soils were similar to sandy loam except that exchangeable Na substituted the CEC of sandy loam.

• Korean Journal of Child Studies
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• v.20 no.1
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• pp.29-44
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• 1999

A major concern in the area of moral education is to find an effective educational method capable of supporting maturity of moral reasoning in young children. The purpose of the present study was to evaluate the effects of distributive dilemma discussion on children's distributive justice reasoning. The subjects were fifty 5-year-olds selected from a kindergarten in the city of Kumi. 26 children participated in a 10 week discussion intervention; another 24 children constituted the control group. The experimental procedure consisted of 3 parts; a pre-test to determine the experimental and control groups, moral discussions on dilemma situations based on 10 stories for the experimental group, and a post-test for both groups. The moral discussions were audio-taped. The results showed that children in the experimental group used more varied and elaborate distributive justice reasoning as the discussions proceeded. Moral discussions facilitated distributive justice reasoning.

• Journal of Science Education
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• v.34 no.1
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• pp.23-32
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• 2010

The purpose of this study was to analyze the trend of domestic studies related to science teaching-learning methods. We reviewed articles published according to year, method, subjects and topic. The methods reported commonly in science education books were extracted. Experiment, cooperative learning, and discussion were methods which had been researched widely. Experimental study of them was utilized most. And next content analysis, survey, and case study were utilized much. The most object of experimental study was middle school students. These reviewed papers showed effects which were related to science achievement, attitude, inquiry ability and self-efficacy. As a result of this study we should research to apply and develop science teaching-learning methods variously. We ought to enlarge research direction to analyze context which applies science teaching-learning methods to educational field by qualitative study. We should try to study effects of teaching-learning methods longitudinally and latitudinally.

• The Mathematical Education
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• v.60 no.4
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• pp.493-508
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• 2021

This study aims to examine the effects of learner-centered mathematical instruction perceived by middle school students such as discussion learning, self-directed learning, and cooperative learning on their math self-efficacy and engagement in mathematics class. Moreover, it attempts to verify if there are differences in the mean of latent variables and effect among groups divided based on achievement level. Research results are as follows. First, discussion learning did not have a direct effect on students' engagement in mathematics class, but still created an indirect effect on it through math self-efficacy. Self-directed learning and cooperative learning created a direct effect on engagement in mathematics class as well as an indirect effect through self-efficacy on mathematics. Second, high-achievement group had a higher perception of discussion learning, self-directed learning, and cooperative learning than a low-achievement group, and showed a higher level of math self-efficacy and engagement in mathematics class. Third, there were significant differences among groups, in the effect of discussion learning on self-efficacy in mathematics, effect of self-directed learning on self-efficacy in mathematics, and effect of math self-efficacy on engagement in mathematics class. Thus, this study offers meaningful implications for the role of math teachers as assistants in learning for learner-centered math classes.

• The Journal of the Korea Contents Association
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• v.15 no.4
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• pp.420-430
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• 2015

This paper investigates the relationships between leader-member exchange(LMX), perceived team efficacy, and organizational citizenship behavior(OCBI, OCBO) in the Korea Post. Also the study investigates the moderator effect of leader integrity and the mediator effect of perceived team efficacy in the relationships between LMX and OCB(OCBI, OCBO). The multiple regression analysis were employed to test the hypotheses. The main finding of this study was as follows: First, LMX had a positive effect on the perceived team efficacy. Second, the perceived team efficacy had a positive impact on OCB(OCBI, OCBO). Third, the perceived team efficacy completely mediated effect on the relationship between LMX and OCBI. Also the perceived team efficacy partially mediated effect on the relationship between LMX and OCBO. Fourth, the positive relationships between LMX and OCB(OCBI, OCBO) were stronger when leader integrity was high rather than low. In particular, this review concludes with implications for future research, limitations of this study, and practical application.

• Journal of The Korean Association of Information Education
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• v.14 no.4
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• pp.619-626
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• 2010

In this study, we performed experimental studies on the educational programming languages of Dolittle and Robot to compare and analyze their effect on improving creativity. We formed three sixth grade classes, totaling 99 students, into a Robot class, a Dolittle class, and a general class that served as a neutral. The Dolittle class and the Robot class took ten programming lessons with specific hand-in operations, as well as feedback and discussion, during ten weeks. The experiment results showed that student creativity in the two programming classes improved more than that of students in the general class. Especially creativity of the students in the Robot class improved the most. Moreover, the mean creativity of the lower academic achievement group was slightly better than that of the higher group. This implies that there is no positive correlation between academic achievement and creativity.

• Journal of Korean Library and Information Science Society
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• v.48 no.1
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• pp.245-265
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• 2017

The objective of this research is to develop & operate classical literature reading education program for youth, to verify the difference in effect with respect to the influence of classical literature reading education on youth's character and competency development and to clarify the difference in effect depending on intention to participate in classical literature reading education and instruction method. Main result of research is summarized as follows. First, after classical literature reading education was found to be effective to the character and the youth's competency development increased. Second, verifying the effect of classical literature reading education on intention to participate voluntarily, it was found to be more effective for group of voluntary participation than group of involuntary participation. Third, verifying the effect of classical literature reading education depending on instruction method, it was found to be more effective for group of discussion lesson based on character key words than group of lesson based on recital.

• Journal of Elementary Mathematics Education in Korea
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• v.20 no.2
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• pp.311-331
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• 2016

The purpose of this study was to analyze mathematical errors and the effects of reflective problem posing activities on students' mathematical problem solving abilities and attitudes toward mathematics. We chose two 5th grade groups (experimental and control groups) to conduct this research. From the results of this study, we obtained the following conclusions. First, reflective problem posing activities are effective in improving students' problem solving abilities. Students could use extended capability of selecting a condition to address the problem to others in the activities. Second, reflective problem posing activities can improve students' mathematical willpower and promotes reflective thinking. Reflective problem posing activities were conducted before and after the six areas of mathematics. Also, we examined students' mathematical attitudes of both the experimental group and the control group about self-confidence, flexibility, willpower, curiosity, mathematical reflection, and mathematical value. In the reflective problem posing group, students showed self check on their problems solving activities and participated in mathematical discussions to communicate with others while participating mathematical problem posing activities. We suggested that reflective problem posing activities should be included in the development of mathematics curriculum and textbooks.

• Journal of Digital Convergence
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• v.16 no.12
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• pp.555-561
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• 2018

It is the Korean language textbook of elementary school 1~2 grade that forms the basis of the textbook to nurture the creative convergence talent with the core competence required by the future society. In order to increase the learning effect based on the textbooks, the interest inducing factors were derived on the basis of the learning interest, and the textbook design was analyzed by the in - depth interviews and discussions of the expert group. As a result, Graphic elements using bright and soft colors, illustrations of peer groups related to learning contents, and resilient use of sans serifs. However, issues such as lack of proper mixing of photos and illustrations, further development of learning helper characters, configuration of spare margins, graphic image design, and lack of a structured layout that utilizes color and visual images were cited as problems.

• Korean Journal of Psychosomatic Medicine
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• v.30 no.2
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• pp.80-98
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• 2022

Posttraumatic stress disorder (PTSD) is well known to have a limited response to drug treatment. Many recently published clinical care guidelines recommend trauma-focused psychotherapies such as cognitive processing therapy (CPT) and prolonged exposure therapy (PE) as first-line treatment and medication such as serotonin reuptake inhibitors and venlafaxine as second-line treatment. Current review introduces the session composition and contents of CPT and presents various CPT studies that show therapeutic effect for civilian and veterans/military with PTSD. In order for clinicians to help effectively patients with PTSD, it is necessary to learn and actively use evidence-based trauma-focused psychotherapies including CPT and PE.