• Journal of Korean Elementary Science Education
• /
• v.38 no.3
• /
• pp.375-386
• /
• 2019

This study explores how elementary school students construct food pyramid prediction models using scientific reasoning. Thirty small groups of sixth-grade students in the Kyoungki province (n=138) participated in this study; each small group constructed a food pyramid prediction model based on scientific reasoning, utilizing prior knowledge on topics such as biotic and abiotic factors, food chains, food webs, and food pyramid concepts. To understand the scientific reasoning applied by the students during the modeling process, three forms of qualitative data were collected and analyzed: each small group's discourse, their representation, and the researcher's field notes. Based on this data, the researcher categorized the students' model patterns into three categories and identified how the students used scientific reasoning in their model patterns. The study found that the model patterns consisted of the population number variation model, the biological and abiotic factors change model, and the equilibrium model. In the population number variation model, students used phenomenon-based reasoning and relation-based reasoning to predict variations in the number of producers and consumers. In the biotic and abiotic factors change model, students used relation-based reasoning to predict the effects on producers and consumers as well as on decomposers and abiotic factors. In the equilibrium model, students predicted that "the food pyramid would reach equilibrium," using relation-based reasoning and model-based reasoning. This study demonstrates that elementary school students can systematically elaborate on complicated ecology concepts using scientific reasoning and modeling processes.

• Economic and Environmental Geology
• /
• v.27 no.3
• /
• pp.281-287
• /
• 1994

The present paper deals with numerical modeling of Love channel waves in transversely isotropic elastic medium. First, an explicit finite-difference scheme of second order approximation is formulated with the wave equation of SH particle displacement in transversely isotropic medium. Since it is a heterogeneous formulation, it should enable efficient modeling of complex model structures without additional treatment of the internal boundary matching. With a model of isotropic coal seam embedded in high velocity host rock, seismograms are synthesized and tutn out to be essentially identical with published ones of Korn and $St{\ddot{o}}ckl$. Next, anisotropic coal seams are investigated. It is found that the horizontal velocity of the seam appears to play a major role of determining the group velocity of Love channel waves. The group velocity increases with the increase of the horizontal velocity or vice versa. However, further study will be needed to exploit fully Love channel waves for the determination of lithology, stratification, fracture in sedimentary rocks, for instance, for hydrocarbon exploration and development.

• Journal of Engineering Education Research
• /
• v.25 no.5
• /
• pp.85-93
• /
• 2022

Capstone Design, a project-based learning technique, is the most important curriculum that clarifying major knowledge and cultivating the ability to apply through the process of solving problems in the industrial field centered on the student project team. Accordingly, various and extensive studies are being conducted for the successful implementation of capstone design courses. Unlike previous studies, this study aimed to quantitatively analyze the opinions that recorded the experiences and feelings of students who performed capstone design, and used text mining methodologies such as frequency analysis, correlation analysis, topic modeling, and sentiment analysis. As a result of examining the overall opinions of the latter period through frequency analysis and correlation analysis, there was a difference between the languages used by the students in the opinions according to gender and project results. Through topic modeling analysis, 'topic selection' and 'the relationship between team members' showed an increase in occupancy or high occupancy, and topics such as 'presentation', 'leadership', and 'feeling what they felt' showed a tendency to decreasing occupancy. Lastly, sentiment analysis has found that female students showed more neutral emotions than male students, and the passed group showed more negative emotions than the non-passed group and less neutral emotions. Based on these findings, students' practical recognition of the curriculum was considered and implications for the improvement of capstone design were presented.

• Korean Journal of Social Welfare
• /
• v.66 no.1
• /
• pp.307-331
• /
• 2014

The purpose of the present study was to explore latent trajectory classes in the longitudinal change of depression measured using CES-D. The study data was extracted from the Korea Welfare Panel Study Data collected from 2006 to 2010. It consisted of 8,900 adults with aged over 19. Growth Mixture Modeling(GMM) was used to explore possible latent trajectory classes in the change of depression over time. The major findings of the present study were as follows. First, there were five latent trajectory classes in the longitudinal change of depression. Second, there were 4 latent trajectory classes of depression for people in a non-poverty group, while there were 3 latent trajectory classes of depression for people in a poverty group. These findings lead to three conclusions. First, 12.1% of the sample shows that their depression level increases over time. Second, the previous research findings of decreased depression over time might be caused by the combination of two latent trajectory classes(a low level depression sustain group and a depression decrease group). Lastly, the latent trajectory classes in the longitudinal change of depression, which are found in the present study, might be caused by interactions among depression, age, and poverty status.

• Korean Journal of Social Welfare Studies
• /
• v.42 no.2
• /
• pp.179-203
• /
• 2011

The purpose of the study is 1) to investigate the reciprocal relationship between cognitive functioning and depressive symptoms and 2) to examine whether there is gender difference in this mutual relationship. The uniqueness of the current study is in its investigation on the simultaneous reciprocal relationship between cognitive functioning and depressive symptoms, which is different from previous studies examining unidirectional relationship. Subjects were 3,511 individuals aged 65 and over who participated in the first and second wave of Korean Longitudinal Study of Ageing. Non-recursive structural equation modeling identified the reciprocal relationship between cognitive functioning and depressive symptoms, with poorer cognitive functioning leading to higher depressive symptoms and higher depressive symptoms resulting in poorer cognitive functioning. Multi-group analysis showed the gender difference in the relationship between cognitive functioning and depressive symptoms. Specifically, cognitive functioning was the significant predictor of depressive symptoms for females, whereas the depressive symptoms was the significant predictor of cognitive functioning for males. These findings indicate that the reciprocal relationship and gender difference should be considered when we development practice implications for prevention and treatment related to depression and cognitive functioning. Based on these findings, implications for theory and practice were discussed.

• Journal of Korean Academy of Nursing
• /
• v.47 no.2
• /
• pp.164-177
• /
• 2017

Purpose: This study was done to develop a strength based I-change smoking cessation program for middle school boys and identified its effects. Methods: The study design was a nonequivalent control group pre-post test design. The participants were 97 middle school students from D city, who were in school from April 6 to September 25, 2015. The experimental group participated in the strength based I-change smoking cessation program, while the comparative group participated in a general smoking cessation program. The control group did not participate in any program. Data analyses involved $x^2$-test, Fishers' exact test, Bonferroni test, and Repeated measures ANOVA, with the IBM SPSS for Windows (version 20.0) program. Results: Compared to the comparison and control groups, the experimental group showed significant improvement in knowledge, attitude, self-efficacy, behavior change. Also cotinine in urine and modeling of social influence in the experimental group significantly decreased after the strength based I-change smoking cessation program. Conclusion: These findings indicate that the strength based I-change smoking cessation program is an effective intervention for middle school boys who smoke. The findings suggest that such programs can be used at public health centers or through school health education to decrease smoking in adolescents.

• Geomechanics and Engineering
• /
• v.10 no.5
• /
• pp.577-598
• /
• 2016

This paper presents a numerical study of pile force distribution in a pile group foundation subjected to vertical load and large moment. The physical modeling of a pile foundation for a wind turbine is analyzed using 3D finite element software, PLAXIS 3D. The soil profile consists of several clay layers, which are modeled as Mohr-Coulomb material in an undrained condition. The piles in the pile group foundation are modeled as special elements called embedded pile elements. To model the problem of a pile group foundation, a small gap is created between the pile cap and underlying soil. The pile cap is modeled as a rigid plate element connected to each pile by a hinge. As a result, applied vertical load and large moment are transferred only to piles without any load sharing to underlying soil. Results of the study focus on pile load distribution for the square shape of a pile group foundation. Mathematical expression is proposed to describe pile force distribution for the cases of vertical load and large moment and purely vertical load.

• Korean Journal of Child Studies
• /
• v.26 no.4
• /
• pp.263-278
• /
• 2005

The purpose of this study was to develop a social skills training program for rejected young children and to investigate the effects of the program. The developed program used several kinds of interaction methods such as instruction, modeling, rehearsal, feedback, and positive reinforcement. The contents of the program are consisted of role-play, art, language activities, and games. The experimental group with a sample of 9 four-year-old children was those children rejected by peers. There were the other 9 children assigned to the control group. The experimental group received the social skills training program for 50-60 minutes per day twice a week during 12 sessions, and the control group received no treatment. And 9 popular children also joined the program from ninth to eleventh sessions. As compared to the control group, children in the experimental group showed a significant increase in peer acceptance and social skills after they participated in the program.

• Human Ecology Research
• /
• v.57 no.1
• /
• pp.41-50
• /
• 2019

This study investigated the significant difference in the influences of pregnant couples' attachment representation for parents of origin on their psychological symptoms according to groups. One hundred and eighty two pregnant couples answered the questionnaire. Data were analyzed by means of frequency, percentages, t-test. Pearson's correlation using SPSS ver. 21.0 and multiple group structural equation modeling using AMOS ver. 20.0. The findings are as follows. First, there were significant differences in attachment representations according to parents of origin and psychological symptoms between pregnant women and spouses. Second, there were negative influences of attachment representations to parents of origin on psychological symptoms for both the pregnant women group and their spouses group, respectively. Last, the negative effects of attachment representation for parents of origin on their psychological symptoms according to groups were significantly different; consequently, the impact on the spouses group was stronger than the pregnant women group. The results imply that policies to help pregnant couples reduce psychological symptoms should be provided. In addition, the unexpected result on the weaker impact of pregnant women's attachment representation for parents of origin on their psychological symptoms suggests it is better to consider other factors simultaneously (such as a romantic attachment to spouses) that might provide a moderating role. The study results are meaningful because it is the first to apply a statistically advanced method to analyze pregnant women and spouses in relation to parents of origin on their psychological symptoms.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.16 no.2
• /
• pp.365-372
• /
• 2002

The mineral medicines mean a sort of mineral or rock for medical treatment and natural material using their chemical components and physical properties. In this study, it was apprehended the mineralogical characteristics of As-bearing group mineral medicines. The extraction test is an vitro test system for predicting the bioavailability of the major and minor elements from mineral medicines and incorporates gastrointestinal tract parameters representative of a human(including stomach and small intestinal pH, stomach mixing time and velocity). The results of the extraction test are used for reaction path modeling in human body. Reaction path modeling in human body can predict digestion with gastric juice as well as bioavailability, speciation. Also, it can predict accumulation of arsenic as pH condition. As the results of the extraction test for digestion, the amounts of Fe extraction was the highest, followed by As, Ca, Ni. In addition, as the results of the reaction path modeling between arsenic compounds and gastric juice using thermodynamic data, when absorbed, major species are followed by H₃As₃S/sub 6/(aq), As₃S/sub 6/ (aq), AsO/sup +/, H₂As₃S/sup 6-/, H₂AsO/sup 3-/, HAs₃S6/sup 2-/, HAsO/sub 3//sup 2-/ and AsO/sub 3//sup 3-/. Specifically the concentration of H₃As₃S/sub 6/(aq) is the highest. As pH increases, the concentration of H₂AsO/sup 3-/, HAsO/sub 3//sup 2-/, HAsO/sub 3//sup 3-/, HAs₃S/sub 6//sup 2-/, H₂As₃S/sup 6-/, and H₃As₃S/sub 6/ increases, whereas the concentration of H₃As₃S/sub 6/ and AsO/sup +/ decreases. On the results of this study, it is able to find out effective and toxic components of poisonous arsenic group of mineral medicines and expected to be widely used for the development of new medicines.