• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.3
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• pp.98-110
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• 2018

In this paper, we propose both Dense grid model and Anchor model to improve the recognition rate of dynamic objects. Two experiments are conducted to study the performance of two proposed CNNs models (Dense grid model and Anchor model), which are to detect dynamic objects. In the first experiment, YOLO-v2 network is adjusted, and then fine-tuned on KITTI datasets. The Dense grid model and Anchor model are then compared with YOLO-v2. Regarding to the evaluation, the two models outperform YOLO-v2 from 6.26% to 10.99% on car detection at different difficulty levels. In the second experiment, this paper conducted further training of the models on a new dataset. The two models outperform YOLO-v2 up to 22.40% on car detection at different difficulty levels.

• Journal of Educational Research in Mathematics
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• v.25 no.3
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• pp.347-366
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• 2015

There are a lot of causes of under-achievement in elementary mathematics, one of which may be lack of previous learning elements. We focus on the understanding of place value. The purpose of this study is to analyze underachievers' levels of understanding of place value concepts and to find the types of place value tasks that they have had special difficulty. For this purpose, an individual test called as "the Six Tasks of Place Value(SToPV)"was applied to ten third grade mathematics underachievers in elementary school. The test is a type of place value concept tests and requires one-on-one interview with some preparation materials. The participants' reactions were analysed according to the framework by Berman(2011). The result of analysis shows that third grade mathematics underachievers tend to have a great difficulty understanding the place value concepts. Also the types of difficult tasks were various from individual to individual. Based on the test results and discussion, we suggested some implications for diagnosing place value concepts of mathematics underachievers.

• Journal of The Korean Association of Information Education
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• v.15 no.4
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• pp.635-644
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• 2011

This research analyzed the brainwave activities and brain hemispherity to find out any implications to design the connections between the activities of the brain function and the computerized arithmetic addition in two difficulty levels: easy: 1-5 vs. hard: 6-9. Thus, in developing the brain based math learning for the computer education by implicit association test(IAT) indicated the significant results for the exclusive brain location and the brain hemispherity on the theta, alpha, low alpha, beta brainwaves by QEEG analysis. The results of this study physiologically supported the theoretical background for the computerized math learning skills as well as the math learning material development. It shows the difficulty levels of math information education and the brain activities on cognitive process of the learner continued on the possible investigation of the brain science.

• Journal of the Korean Society of Safety
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• v.24 no.3
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• pp.71-78
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• 2009

During a learning process, a human being is assumed to experience knowledge-based behaviors, rule-based behaviors, and skill-based behaviors sequentially if Rasmussen was right. If any psycho-physiological symptom to those different levels can be obtained, it can be useful as a measure whether a human being is fully trained and has gotten a skill in his work. Therefore, this study aimed to draw relationships between human performance measures and psycho-physiological measures while committing a computer-simulated pointing task by utilizing the power spectrum technique of EEG data, especially with the ratio of relative beta-to-alpha band power. The result showed that, during correct responses, the ratio came to stabilize as all the performance data went stable. However, response time was not a simple linear function of task difficulty level only, but a joint function of task characteristics as well as behavior levels. Comparing relative band power ratios from errors and correct responses, activated states of one's brain could be explained, and characteristics of the task could understood. To tell that of pointing task, correlations around C3, C4, P3, P4 and 01, 02 area were significant and high in correct response cases whereas most correlation coefficients went down in error cases standing for imbalance of psycho-motor functions. Though task difficulty was the only one factor that could influence on relative band power ratio with statistical significance, it should be comprehended to mean a different way of expression indicating task characteristics since at least error-some situation could be explained with the help of relative band power ratio that absolute band power failed.

• The Journal of Korean Association of Computer Education
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• v.22 no.3
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• pp.25-35
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• 2019

The backward design suggested in the 2015 revised curriculum takes into consideration the consistency between a goal and its evaluation, and emphasizes the essence of knowledge. However, the method for designing lesson plans is different from those of the past and, as a result, teachers in the field have experienced some difficulty in applying the design. Accordingly, this study was aimed at examining the differences between the taxonomy of educational objectives with which teachers are familiar and the viewpoint of informatics. The result of the analysis indicated no difference when applying the hierarchy of the six-sided view of the concept of understanding, of which teachers felt some difficulty in terms of applying the backward design. However, the analysis did show some similarity to the hierarchy of the six levels suggested in the taxonomy of the educational objectives. In general, when a new theory is suggested, it is very difficult for it to be accepted and applied. This study holds significance in that it suggests that a new theory must be accepted on the basis of sufficient analysis along with the necessity of efforts to be dedicated in order to increase its applicability.

• Journal of the Korean Society of School Health
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• v.36 no.3
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• pp.113-125
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• 2023

Purpose: The purpose of this study is to develop a model for predicting mental health risk among adolescents based on health behavior information by employing a hybrid machine learning method. Methods: The study analyzed data of 51,850 domestic middle and high school students from 2022 Youth Health Behavior Survey conducted by the Korea Disease Control and Prevention Agency. Firstly, mental health risk levels (stress perception, suicidal thoughts, suicide attempts, suicide plans, experiences of sadness and despair, loneliness, and generalized anxiety disorder) were classified using the k-mean unsupervised learning technique. Secondly, demographic factors (family economic status, gender, age), academic performance, physical health (body mass index, moderate-intensity exercise, subjective health perception, oral health perception), daily life habits (sleep time, wake-up time, smartphone use time, difficulty recovering from fatigue), eating habits (consumption of high-caffeine drinks, sweet drinks, late-night snacks), violence victimization, and deviance (drinking, smoking experience) data were input to develop a random forest model predicting mental health risk, using logistic and XGBoosting. The model and its prediction performance were compared. Results: First, the subjects were classified into two mental health groups using k-mean unsupervised learning, with the high mental health risk group constituting 26.45% of the total sample (13,712 adolescents). This mental health risk group included most of the adolescents who had made suicide plans (95.1%) or attempted suicide (96.7%). Second, the predictive performance of the random forest model for classifying mental health risk groups significantly outperformed that of the reference model (AUC=.94). Predictors of high importance were 'difficulty recovering from daytime fatigue' and 'subjective health perception'. Conclusion: Based on an understanding of adolescent health behavior information, it is possible to predict the mental health risk levels of adolescents and make interventions in advance.

• Journal of Broadcast Engineering
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• v.3 no.1
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• pp.100-109
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• 1998

The coding of video sequences has been the focus of research in recent years. High Definition TV(HDTV), video conferencing and video on demand(VOD) are some of the well known applications. In the moving picture compression, motion estimation algorithm plays a very important role, but due to its high computational complexity, there has been many approaches to overcome this difficulty. We propose a new block matching criterion that uses modified cost functions. This new block matching criterion classifies pixels into 2-levels, 4-levels and 8-levels with a suitable thresholding method. We also show that our new proposed algorithms can easily be combined with many other fast motion estimation algorithms with good performance.

• Physical Therapy Korea
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• v.17 no.2
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• pp.51-59
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• 2010

The Functional Independence Measure (FIM) is widely used to determine the dependency of activity of daily living in rehabilitation patients. The purposes of this study were to evaluate the unidimentionality of the FIM physical items and to analyze the validity of cross-functional levels in stroke survivors in Korea. Thirteen physical items of FIM were rated according to an ordinal scale of a 7-level classification. Two hundred and seventy-nine patients participated in the study (age range 18~92 years and 57% male). Six items-eating, bladder control, bowel control, transfer to and from the bed/wheelchair, transfer to and from the toilet, and bathing-showed misfits with the Rasch model. The most difficult item was 'bathing', the easiest item was 'bowel control'. Although there were several differences within functional levels, the hierarchical order of item measures was rather similar. 'Bathing' was the most difficult in high level patients (above 60), however 'stairs' was most difficult in the middle level (41~60) group. In the low level group (below 40), 'toileting' was the most difficult. In conclusion, the present study has shown several differences of item difficulty among functional levels. This result will be useful in planning interventions, and developing rehabilitation programs for stroke survivors.

• Journal of The Korean Association For Science Education
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• v.24 no.4
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• pp.687-708
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• 2004

The purpose of this study is to investigate the relationships between cognitive conflict and students' causal attributions and to find out what kinds of attributions affect successful resolution of cognitive conflict in learning physics. Twenty-nine college students who attended a base general physics course took an attribution test and a conceptual pretest related to action and reaction concept. Of these, twenty students who revealed alternative conceptions were selected. They were confronted with a discrepant demonstration and took part in the cognitive conflict level test, a posttest, and delayed posttest. Those students who experienced high levels of cognitive conflict were selected and interviewed to find out what kinds of attributions affect resolving the conflict. When confronted with the discrepant event, the students who attributed success outcomes to "effort" experienced higher levels of cognitive conflict than those to "task difficulty." However, those students who revealed high levels of cognitive conflict and attributed success outcomes to effort did not always produce conceptual change. They had different perspectives on effort and conducted different effort activities to resolve the cognitive conflict. In addition, these effort activities appeared to include their motivational beliefs, metacognitive and volitional strategies. The results of this study indicate that in order for the conflicts to lead to change, students need to have the perspective on effort implying the use of the self-regulated learning strategy and to conduct effort activities based on them. Beyond cold conceptual change, this article suggests that there is a management strategy of cognitive conflict in the classroom context.

• International Journal of Contents
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• v.13 no.4
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• pp.16-22
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• 2017

The purpose of this study was to investigate the daily life experiences of medical students and to explore gender differences in these experiences using the Experience Sampling Method (ESM) as the method. The instrument, the Experience Sampling Form (ESF), consisted of questions on the external and internal experiences of the respondents. Data were collected from 2,035 ESFs by 91 students (male=52, female=39) at three medical schools for one week. The data was analyzed using the statistical tests of the t-test and ${\chi}^2$ test. Activity places were significantly different by gender (${\chi}^2=16.576$, p=.001). Males spent more time in learning places such as schools, libraries, etc., whereas females spent their time in personal places, including their homes, dormitories, etc. Males undertook more learning activities than did females, and females undertook more social/leisure activities and basic life activities than did male students (${\chi}^2=18.753$, p=.001). They were in a learning place and performing learning activities. There were significant perceptual differences between males and females about their flow levels, competency levels, and difficulty levels, based on the activity type. These results can help us to understand the daily lives of medical students and can be useful in developing counseling programs and educational activities for students.