• Korean Journal of Child Studies
• /
• v.30 no.2
• /
• pp.43-55
• /
• 2009

This study investigated trajectories of change in the career maturity of elementary school students and of attachment to parents and academic achievement as predictors of change. The 2844 participants were 1524 boys and 1320 girls in the Korea Youth Panel Survey. They were fourth graders in 2004 and became seventh graders in 2007. Latent growth curve modeling indicated that : (1) Trajectories of change in career maturity from fourth grade to seventh grade modeled quadratic growth. (2) Variance of career maturity in initial levels, linear slope and quadratic slope indicated individual differences intrajectories of change in career maturity. (3) Attachment to parents influenced initial levels of career maturity academic achievement influenced both initial levels and linear slope of career maturity.

• Journal of The Korean Association For Science Education
• /
• v.24 no.1
• /
• pp.1-16
• /
• 2004

The purpose of this study was to examine the role of cognitive conflict in the conceptual change process. Ninety-seven high school students in Korea participated in this study. Before instruction, we conducted pretests to measure learning motivation and learning strategies. During instruction, we tested the students' preconceptions about Newton's 3rd Law and presented demonstrations. After this, we tested the students' cognitive conflict levels and provided students learning sessions in which we explained the results of the demonstrations. After these learning sessions, we tested the students' state learning motivation and state learning strategy. Posttests and delayed posttests were conducted with individual interviews. The result shows that cognitive conflict has direct/indirect effects on the conceptual change process. However, the effects of cognitive conflict are mediated by other variables in class, such as state learning motivation and state learning strategy. In addition, we found that there was an optimal level of cognitive conflict in the conceptual change process. We discuss the complex role of cognitive conflict in conceptual change, and the educational implications of these findings.

• Proceedings of the Korea Inteligent Information System Society Conference
• /
• 2000.11a
• /
• pp.417-426
• /
• 2000

This study suggests integrated neural network models for Interest rate forecasting using change-point detection, classifiers, and classification functions based on structural change. The proposed model is composed of three phases with tee-staged learning. The first phase is to detect successive and appropriate structural changes in interest rare dataset. The second phase is to forecast change-point group with classifiers (discriminant analysis, logistic regression, and backpropagation neural networks) and their. combined classification functions. The fecal phase is to forecast the interest rate with backpropagation neural networks. We propose some classification functions to overcome the problems of two-staged learning that cannot measure the performance of the first learning. Subsequently, we compare the structured models with a neural network model alone and, in addition, determine which of classifiers and classification functions can perform better. This article then examines the predictability of the proposed classification functions for interest rate forecasting using structural change.

• Journal of the Korean Chemical Society
• /
• v.65 no.2
• /
• pp.145-150
• /
• 2021

The present study describes a hands-on experiment to help students understand the concept of phase change or phase transition and its application in a phase change material (PCM). PCMs are substances that have the capability of storing and releasing large amounts of thermal energy. They act as energy storage materials that provide an effective way to save energy by reducing the electricity required for heating and cooling. Lauric acid (LA) was selected as an example of the PCM. Students investigated the temperature change of LA and the temperature (of air) inside the test tube. The differences in the temperatures of the systems helped students understand how PCMs work. A one-group pretest and posttest design was implemented with 34 grade-11 students in science and mathematics. Students' understanding was assessed using a multiple-choice test and a questionnaire. The findings revealed that the designed activity helped students understand the concept of phase change and its application to materials for thermal energy storage.

• Journal of Information Processing Systems
• /
• v.18 no.4
• /
• pp.587-598
• /
• 2022

To increase building change recognition accuracy, we present a deep learning-based building change detection using remote sensing images. In the proposed approach, by merging pixel-level and object-level information of multitemporal remote sensing images, we create the difference image (DI), and the frequency-domain significance technique is used to generate the DI saliency map. The fuzzy C-means clustering technique pre-classifies the coarse change detection map by defining the DI saliency map threshold. We then extract the neighborhood features of the unchanged pixels and the changed (buildings) from pixel-level and object-level feature images, which are then used as valid deep neural network (DNN) training samples. The trained DNNs are then utilized to identify changes in DI. The suggested strategy was evaluated and compared to current detection methods using two datasets. The results suggest that our proposed technique can detect more building change information and improve change detection accuracy.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.26 no.3
• /
• pp.528-536
• /
• 2002

As one step for the safety performance of LNG storage tank, the change in fracture toughness within the X-grooved weld heat-affected zone (HAZ) of newly developed 9% Ni steel, which was submerged arc (SA)-welded, was investigated. Both crack initiation fracture toughness and crack arrest fracture toughness were evaluated by the crack tip opening displacement (CTOD) tests and compact crack arrest (CCA) tests. As the evaluated region approached the fusion line, each test result shorted different tendency, that is, crack initiation toughness decreased while crack arrest toughness increased. The results were discussed through the observation of the microstructural change.

• Journal of Climate Change Research
• /
• v.2 no.4
• /
• pp.221-235
• /
• 2011

This study summarizes previous studies on the climate change over Korea. Several studies on climate change in the neighboring countries as well as the entire globe are reviewed. Temperature data obtained from modern observational system show an increasing trend beyond the natural variations. The increasing rate of sea surface temperature (SST) over the ocean basins surrounding Korea is higher than that of the global-mean SST. The large increase in the SST over the oceans surrounding Korea may enhance tropical cyclone activity and heavy rainfall frequency in Korea. In addition, it has been reported that the changes in large scale circulation associated with global climate change influence the spatio-temporal variation of monsoon including Changma in summer and cold surges in winter. Although all researches on the subject were not fully discussed in this study due to short period of preparation, allowed pages, and authors' limited knowledge, we expect that this summarized reviews would be helpful to understand climate changes over Korea and the surrounding regions.

• Korean Journal of Childcare and Education
• /
• v.12 no.5
• /
• pp.137-155
• /
• 2016

The purpose of the present study was to investigate the longitudinal relationship between main caregivers' life satisfaction and depression and self-esteem of school-aged children, and to provide plans for improving the lives of the school-aged children. For this purpose, we analyzed the three years'longitudinal panel data (2011-2013) of the Korean Children and Youth Panel Survey (KCYPS) including 2,342 first grade elementary school children employing the latent growth model using SPSS 18.0 and AMOS 22.0. Analysis results were as follows. First, main caregivers'life satisfaction and school-aged children's depression increased as time passes and linear change model was selected. Second, the initial status of main caregivers'life satisfaction had effects on the initial status of their children's depression, but initial status and rates of change of life satisfaction did not have an influence on the rates of change of the depression. However, it was found that the main caregivers' life satisfaction had effects on the school-aged children's self-esteem and it worked as a mediator on the longitudinal relationship between the main caregivers'life satisfaction and the children's depression. School-aged children's self-esteem was a partial mediator on the initial status of their depression and full mediator on these rates of change. These findings suggests that programs improving school-aged children's self-esteem should be developed.

• Journal of the Korean School Mathematics Society
• /
• v.22 no.3
• /
• pp.221-240
• /
• 2019

The purpose of this study is to suggest Reciprocal Peer Tutoring(RPT) for mathematics underachieving students as one way of the instructional strategies to supplement their lack of mathematics learning and to provide them with successful experiences in learning mathematics. We defined underachieving student in mathematics as the student whose mathematics achievement was high or middle level in the middle school but became lower in high school. Four mathematics underachievers voluntarily participated in this study. We examined the effects and roles of RPT by focusing on their positive change in the affective domain. RPT was conducted for about three months, including pre-training, pretest, and posttest. As the results of this research, RPT has generally made positive changes in the affective domain of underachieving mathematics students. Although four students did not show the same pattern of change and the sub-elements of positive change were different for each student, RPT provided opportunities for 4 all students to experience positive change.

• Journal of the Korean Society of Food Culture
• /
• v.24 no.2
• /
• pp.146-154
• /
• 2009

This study was conducted to investigate the vegetable eating behaviors and preferences of elementary school students by stage of change for vegetable intake. The subjects consisted of 191 fourth and fifth grade elementary school students from Gyeonggi province. The stage of change for vegetable intake was categorized into three groups: precontemplation (PC, 18.4%), preparation (P, 43.5%), and action/maintenance (A&M, 48.2%). The trend to eat a variety of foods was more distinctive as the students went from the PC to the A&M stage. The stage of change for vegetable intake was closely related with the kimchi-eating pattern of the students. The A&M group ate more vegetables than the PC group because they liked vegetables and/or wanted to prevent disease. The PC group had a lower tendency to follow recommendations for vegetable eating than the P and A&M groups. The PC group also had an incorrect notion that low vegetable consumption over an extended time would not have a big impact on their health. The vegetables of high preference for the elementary school students were potato, sweet potato, lettuce, radish, perilla leaf, cucumber, and cabbage. The vegetables of low preference were spinach, onion, balloon flower, and green pepper. The PC group had lower preferences for most vegetables than the P and A&M groups. Therefore, careful nutrition education is necessary especially for students in the PC group in order to explain the positive effects of vegetable intake and negative effects of an unbalanced diet. It is also necessary to survey students' tastes consistently and to develop recipes that encourage them to consume more vegetables agreeably.