• Advances in nano research
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• v.15 no.5
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• pp.467-484
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• 2023

Despite the significant features of fiber-reinforced cementitious composites (FRCCs), including better mechanical, fractural, and durability performance, their high content of cement has restricted their use in the construction industry. Although ground granulated blast furnace slag (GGBFS) is considered the main supplementary cementitious material, its slow pozzolanic reaction stands against its application. The addition of nano-sized mineral modifiers, including nano-silica (NS), is an alternative to address the drawbacks of using GGBFS. The main object of this empirical and numerical research is to examine the effect of NS on the strain-hardening behavior of cementitious composites; ten mixes were designed, and five levels of NS were considered. This study proposes a new method, using a four-point bending test to assess the use of nano-silica (NS) on the flexural behavior, first cracking strength, fracture energy, and micromechanical parameters including interfacial friction bond strength and maximum bridging stress. Digital image correlation (DIC) was used for monitoring the initiation and propagation of the cracks. In addition, to attain a deep comprehension of fiber/matrix interaction, scanning electron microscope (SEM) analysis was used. It was discovered that using nano-silica (NS) in cementitious materials results in an enhancement in the matrix toughness, which prevents multiple cracking and, therefore, strain-hardening. In addition, adding NS enhanced the interfacial transition zone between matrix and fiber, leading to a higher interfacial friction bond strength, which helps multiple cracking in the composite due to the hydrophobic nature of polypropylene (PP) fibers. The findings of this research provide insight into finding the optimum percent of NS in which both ductility and high tensile strength of the composites would be satisfied. As a concluding remark, a new criterion is proposed, showing that the optimum value of nano-silica is 2%. The findings and proposed method of this study can facilitate the design and utilization of green cementitious composites in structures.

• The Mathematical Education
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• v.63 no.2
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• pp.209-231
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• 2024

The education sector is undergoing significant changes due to the Fourth Industrial Revolution and the advancement of artificial intelligence. Particularly, the importance of education based on artificial intelligence is being emphasized. Accordingly, the purpose of this study is to develop a statistics education program using deep learning prediction in high school mathematics and to examine the impact of such statistically problem-solvingcentered statistics education programs on high school students' statistical literacy and computational thinking. To achieve this goal, a statistics education program using deep learning prediction applicable to high school mathematics was developed. The analysis revealed that students' understanding of context improved through experiencing how data was generated and collected. Additionally, they enhanced their comprehension of data variability while exploring and analyzing various datasets. Moreover, they demonstrated the ability to critically analyze data during the process of validating its reliability. In order to analyze the impact of the statistics education program on high school students' computational thinking, a paired sample t-test was conducted, confirming a statistically significant difference in computational thinking between before and after classes (t=-11.657, p<0.001).

• Korean Journal of Psychosomatic Medicine
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• v.20 no.1
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• pp.50-58
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• 2012

Objectives : This study examined the selective deficits of executive function in patients with mild traumatic brain injury that in normal range of general intelligence level and aimed to analysis of the correlation between K-WAIS result and executive function. Methods : 59 subjects were included in this study, who were diagnosed as mild traumatic brain injury(MTBI) and they have visited in neuropsychiatric department of Wonkwang University Hospital during from March, 2005 to September, 2010. For measurement of general intelligence quotient, the Korean-Wechsler Adults Intelligence Scale(K-WAIS) was administered and for measurement of executive intelligence quotient(EIQ), Executive Intelligence Test(EXIT) was administered. Results : Of patients, 50.8% included at abnormal EIQ group. The patients of abnormal EIQ showed poorer full scale IQ(FIQ), performance IQ(PIQ) and in subscale that picture arrangement, digit symbol, digit span, block design, object assembly and comprehension were significantly different. In terms of relationships between K-WAIS and EIQ, FIQ and PIQ have positive correlation with EIQ. And in subscale, picture arrangement, digit symbol, digit span, block design, object assembly and comprehension show positive correlation with EIQ. Conclusion : This study suggest that MTBI patients with have normal range of general intelligence level may have deficit of executive function is common. The decline of FIQ, PIQ and some subscales of K-WAIS may suggest executive dysfunction in MTBI patients.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.2020-2028
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• 2015

This study was conducted in order to identify factors influencing maternal-fetal attachment among pregnant women, considering the factors presented in Mercer's theory: Becoming a Mother(pregnancy stress, self-esteem, dyadic adjustment, sense of mastery, antepartum stress). The data was collected through structured questionnaires from 140 pregnant women who visited the obstetric clinic and public health centers in a metropolitan area to have prenatal tests from August 23th to November 25th 2014. The data were analyzed by SPSS 20 software using descriptive statistics, the t-test, ANOVA, the Pearson's correlation coefficients and a stepwise multiple regression. The results were as follows: Maternal-fetal attachment in the group of pregnant women under 30 years of age was significantly higher than that in the group of over the age of 31(t=2.79,p=.004). Primiparas had higher maternal-fetal attachment than multiparas(F=3.27, p=.041). There was a negative correlation between pregnancy stress(r=-0.22, p=.009) and maternal-fetal attachment. Self-esteem (r=0.45, p<.001), dyadic adjustment(r=0.42, p<.001), sense of mastery(r=0.24, p=.005) and maternal-fetal attachment were, however, positively correlated. It was found that self-esteem, dyadic adjustment and age were some of the factors influencing maternal-fetal attachment among pregnant women. These variables explained 26.1% of the variance in maternal-fetal attachment. Findings of this study indicate needs for comprehension and assessment of self-esteem and dyadic adjustment in pregnant women through prenatal tests. Also, the intervention programs to improve maternal-fetal attachment among older mothers should be developed and implemented.

• Journal of Science Education
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• v.37 no.2
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• pp.374-388
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• 2013

The purpose of this study was to investigate pre-service physics teachers' perceptions on the physics education major curriculum. We surveyed 15 junior, and 13 senior college students of physics education major in an university in southern part of Korea. Among them, 24 participants(86 %) took the physics 1 course in high school and 22 participants(79 %) chose the physics 1 in their Korea Scholastic Aptitude Test. The responses showed that the most necessary part in pre-service students' learning was the understanding of high school level physics(36 %), and the understanding of introductory level physics(29 %). In the wish list of courses to be open, high school level physics course was ranked first among seven options by 61 % of respondents. Also, there was some concurrence among respondents in opinion of the necessity for understanding introductory physics. Students felt difficulties in understanding it especially owing to the lack of problem solving skill and comprehension. They added that the sufficient explanation of core concepts should be the first action in the innovative plan. Most participants of pre-service physics teachers hoped to have the revised major curriculum which could help their understanding of high school level or introductory level of physics. However, there was a gap of opinions between the group of students with completion of the high school physics 1 & 2 course and those with non-completion of them. The approach of changing major curriculum with consideration of learners' needs was recommended because the number of students with completion of the high school physics course would probably be decreasing rapidly under these circumstances such as the application of new national curriculum, the reduction of the number of the elective courses in Korea Scholastic Aptitude Test and so on.

• Design Convergence Study
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• v.13 no.2
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• pp.143-164
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• 2014

In this study, we suggest a tablet-PC based application as an instrument for self-examination of dementia and aim to evaluate its usability for the practical use. The tool for the self-diagnosis of dementia is testing a person's sentence comprehension, which is investigated by the accuracy of a sentence-picture matching task, and the result of the test can differentiate individuals with dementia of Alzheimer's type from normal aging population. According to its use for diagnosis of dementia, we developed a new version of sentence-picture matching task by a cooperative study with NABLE(Neurogenic communication And Brain Lab at Ewha) and applied to the application as a main function. Targeting the New Silver who are preliminary aged people in Korea, this application can provide them with three values: 'self-', 'easy', and 'simple'. When using this application, users can gain these values by an instruction manual with the recorded guide voice, easy-to-use functions and the simplified menu structure of it. After prototyping, we conducted the usability test and it was proved as a result that the New Silver users can easily operate the application by themselves.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.17 no.2
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• pp.131-140
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• 2006

Objectives : This study was conducted to investigate the deficits of executive function in children with ADHD, Asperger's Disorder(AD), and teaming disorder (LD), and to identify the differential characteristics of executive function deficits among three groups. Methods : The clinical group consisted of 46 children between the ages of 7 and 15 (16 ADHD, 16 LD, 14 AD). Neuropsychological tests for measuring cognitive function, attention and executive function were individually administered to children, and their performance scores were calculated based on the age norm for each test. Results : There was no significant difference in FSIQ, VIQ, and PIQ among the three groups. However, the AD group tended to show higher scores on the subtests of Information, Vocabulary and Digit Span, and lower score on Comprehension subtest than the ADHD and LD groups, while the LD group tended to show the lowest scores on the Information and Vocabulary subtests. On ADS, the ADHD group showed the highest omission and commission errors. All groups showed poor performances belonging to below 25 percentile ranks on executive function tests when compared to the age norms of normative group. The number of completed category on WCST was the smallest in the ADHD group, while the working memory score was the lowest in the LD group. Conclusion : These results suggest that ADHD, LD, and AD children have executive function deficit in common. However, the specific deficit areas in executive function are different for each group.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.945-953
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• 2006

The researchers in the field of cognitive science and learning science suggest that the teaching activity induces the elaborative and meaningful learning. Actually, lots of research findings have shown the beneficial effect of learning by teaching such as peer tutoring. But peer tutoring has some limitations in the practical learning context. To overcome some limitations, the new concept of "learning by teaching" through the agent called Teachable Agent. The teachable agent is a modified version of traditional intelligent tutoring system that assigns a role of tutor to teach the agent. The teachable agent monitors individual difference and provides a student with a chance for deep learning and motivation to learn by allowing them to play an active role in the process of learning. That is, The teaching activity induces the elaborative and meaningful learning. This study compared the effects of our teachable agent, KORI, and peer tutoring on the cognition and motivation. The field experiment was conducted to examine whether learning by teaching the teachable agent would be more effective than peer tutoring and reading condition. In the experiment, all participants took 30 minutes lesson on rock and rock cycle together to acquire the base knowledge in the domain. After the lesson, participants were randomly assigned to one of the three experimental conditions; reading condition, peer tutoring condition, and teachable agent condition. Next, participants of each condition moved into separated place and performed their own learning activity. After finishing all of the learning activities in each condition, all participants were instructed to rate the interestingness using a 5-point scale on their own learning activity and leaning material, and were given the comprehension test. The results indicated that the teachable agent condition and the peer tutoring condition showed more interests in the learning than the reading condition. It is suggested that teachable agent has more advantages in overcoming the several practical limitations of peer tutoring such as restrictions in time and place, tutor's cognitive burden, unnecessary interaction during peer tutoring. The applicability and prospects of the teachable agent as an efficient substitute for peer tutoring and traditional intelligent tutoring system were also discussed.

• Journal of Science Education
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• v.39 no.3
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• pp.418-433
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• 2015

In this study, we investigated the cognitive characteristics of low science achieving middle school students in K-WISC-IV, and compared the results with high science achieving and achieving students. The results showed us that high science achieving students scored higher than counterparts in FSIQ. Low science achieving students scored lower than high science achieving and achieving students in VCI. Especially low science achieving students scored lower than two groups in subtest SI. The low level of abstraction in low science achieving students is due to the lack of scientific reasoning ability. Therefore subtest SI is considered as highly discriminating test for low science achieving group. Low levels in verbal comprehension, abstraction and reasoning ability are the major factors in poor school performance. High science achieving students scored more than achieving and low achieving students in WMI. Because the working memory is involved in scientific reasoning problem solving process, it is believed to play an important role in science achieved.

• Journal of Engineering Education Research
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• v.12 no.4
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• pp.142-149
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• 2009

This paper deals with the analysis and comparison between on the course of a conventional engineering design (typically project-based learning) and a new engineering design (introduced PBL model to conventional engineering design). The purpose of the study is to identify and prove the effect of PBL model on the course with a new teaching-learning. In the result of t-test, there were significant statistics in the creative problem solving and self-directed learning ability, but no significant statistics in the team work and communication skill ability. Also the average of factors of the problem-based strategy is higher than those of the project-based strategy. In the problem-based strategy, the team work has the most influential on the satisfactory of the course. However in the project-based strategy, the comprehension of given product has the most influential on the satisfactory. Finally, this study has proved the effect of PBL on the course engineering design.