• Journal of Biomedical Engineering Research
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• v.33 no.1
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• pp.39-46
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• 2012

Electrical impedance tomography(EIT) can produce functional images with conductivity distributions associated with physiological events such as cardiac and respiratory cycles. EIT has been proposed as a clinical imaging tool for the detection of stroke and breast cancer, pulmonary function monitoring, cardiac imaging and other clinical applications. However EIT still suffers from technical challenges such as the electrode interface, hardware limitations, lack of animal or human trials, and interpretation of conductivity variations in reconstructed images. We improved the KHU Mark2 EIT system by introducing an EIT electrode interface consisting of nano-web fabric electrodes and by adding a synchronized biosignal measurement system for gated conductivity imaging. ECG and respiration signals are collected to analyze the relationship between the changes in conductivity images and cardiac activity or respiration. The biosignal measurement system provides a trigger to the EIT system to commence imaging and the EIT system produces an output trigger. This EIT acquisition time trigger signal will also allow us to operate the EIT system synchronously with other clinical devices. This type of biosignal gated conductivity imaging enables capture of fast cardiac events and may also improve images and the signal-to-noise ratio (SNR) by using signal averaging methods at the same point in cardiac or respiration cycles. As an example we monitored the beat by beat cardiac-related change of conductivity in the EIT images obtained at a common state over multiple respiration cycles. We showed that the gated conductivity imaging method reveals cardiac perfusion changes in the heart region of the EIT images on a canine animal model. These changes appear to have the expected timing relationship to the ECG and ventilator settings that were used to control respiration. As EIT is radiation free and displays high timing resolution its ability to reveal perfusion changes may be of use in intensive care units for continuous monitoring of cardiopulmonary function.

• Journal of The Korean Association For Science Education
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• v.18 no.1
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• pp.35-42
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• 1998

To investigate 13 year old pupils' suggested aims, recognition of relevant variable, and the relationship between the suggested aim and the conclusion which is drawn by pupils, we classified experiments in textdbook into three cases: (1) Case involving dependent variable and independent variable in the title of experiment, (2) Case involving dependent variable only, where pupils can know independent variable from the content of textbook, (3) Case involving dependent variable only, where pupils hardly can know independent variable from the content of textbook. In respect of the aims which pupils suggested, the suggested aims were reduced to the title of experiment in case(1). However, the suggested aims were divided into several forms which is not relevant to the content of experiment in case (2), (3). This shows that pupils are affected by the title of experiment according to how the variable is involved in the title of experiment. This is supported by the fact that when the variable is described in the title, the suggested aim is reduced to the title of experiment. On the other hand, there was a relationship between the suggested aim and the drawn conclusion in case (1). But there was few relationships in case (2) and (3). Surprisingly, the drawn conclusion in case(1) was not consistent with the expected one because of the inappropriate experimental setting. We need to be more careful in experimental setting, pupils' cognitive ability, and openness of experiment to help pupils perform experiment successfully.

• Journal of Digital Convergence
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• v.15 no.11
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• pp.407-412
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• 2017

In the film Inception, we can see that the human dream world is depicted using Freud's psychoanalytical subconscious theory. Through the expression of the subconscious, And the ability to think and think deeply of human nature, such as presenting a new perspective to insight and expression. Based on Freud 's subconscious theory, this paper explores the expression of the dream world and the subconscious in the film and examines the meaning expression of the film through it. The main character is well described as living a chaotic life in obsession with obsessions and obsessions due to his subconscious uncontrollable through his dreams and dreams of being satisfied by the way the oppressed thoughts and desires are disguised I feel that I feel my foolishness and mood as a masturbation by dreaming and dreaming to turn back the moments of regret. In addition, conflicts and confrontations between consciousness and subconscious are expressed well in the form of confusion in reality and dreams. This application and application of humanities studies is a good example of the production of in-depth popular arts content, as we can see that it can add to the weight of depth setting, plot development, and above all creative time and space creation.

• Journal of the Korean Association of Geographic Information Studies
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• v.5 no.2
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• pp.16-24
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• 2002

Classification of the land cover characteristics is a major application of remote sensing. The goal of this study is to propose an optimal classification process for electro-optical camera(EOC) of Korea Multi-Purpose Satellite(KOMPSAT). The study was carried out on Landsat TM, high spectral resolution image and KOMPSAT EOC, high spatial resolution image of Miho river basin, Korea. The study was conducted in two stages: one was image fusion of TM and EOC to gain high spectral and spatial resolution image, the other was land cover classification on fused image. Four fusion techniques were applied and compared for its topographic interpretation such as IHS, HPF, CN and wavelet transform. The fused images were classified by radial basis function neural network(RBF-NN) and artificial neural network(ANN) classification model. The proposed RBF-NN was validated for the study area and the optimal model structure and parameter were respectively identified for different input band combinations. The results of the study propose an optimal classification process of KOMPSAT EOC to improve the thematic mapping and extraction of environmental information.

• Journal of Educational Research in Mathematics
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• v.17 no.4
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• pp.453-475
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• 2007

School algebra starts with introducing algebraic expressions which have been one of the cognitive obstacles to the students in the transfer from arithmetic to algebra. In the recent studies on the teaching school algebra, algebraic thinking is getting much more attention together with algebraic expressions. In this paper, we examined the processes of the transfer from arithmetic to algebra and ways for teaching early algebra through algebraic thinking factors. Issues about algebraic thinking have continued since 1980's. But the theoretic foundations for algebraic thinking have not been founded in the previous studies. In this paper, we analyzed the algebraic thinking in school algebra from historico-genetic, epistemological, and symbolic-linguistic points of view, and identified algebraic thinking factors, i.e. the principle of permanence of formal laws, the concept of variable, quantitative reasoning, algebraic interpretation - constructing algebraic expressions, trans formational reasoning - changing algebraic expressions, operational senses - operating algebraic expressions, substitution, etc. We also identified these algebraic thinking factors through analyzing mathematics textbooks of elementary and middle school, and showed the middle school students' low achievement relating to these factors through the algebraic thinking ability test. Based upon these analyses, we argued that the readiness for algebra learning should be made through the processes including algebraic thinking factors in the elementary school and that the transfer from arithmetic to algebra should be accomplished naturally through the pre-algebra course. And we searched for alternative ways to improve algebra curriculums, emphasizing algebraic thinking factors. In summary, we identified the problems of school algebra relating to the transfer from arithmetic to algebra with the problem of teaching algebraic thinking and analyzed the algebraic thinking factors of school algebra, and searched for alternative ways for improving the transfer from arithmetic to algebra and the teaching of early algebra.

• Science of Emotion and Sensibility
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• v.21 no.3
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• pp.151-164
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• 2018

The appropriate interpretation of social cues is a crucial ability for everyday life. While processing socially relevant information, beyond the low-level physical features of the stimuli to emotional information is known to influence human cognition in various stages, from early perception to later high-level cognition, such as working memory (WM). However, it remains unclear how the influence of each type of emotional information on cognitive processes changes in response to what has occurred in the processing stage. Past studies have largely adopted face stimuli to address this type of research question, but we used a unique class of socially relevant motion stimuli, called biological motion (BM), which depicts various human actions and emotions with moving dots to exhibit the effects of anger, happiness, and neutral emotion on task performance in perceptual and working memory. In this study, participants determined whether two BM stimuli, sequentially presented with a delay between them (WM task) or one immediately after the other (perceptual task), were identical. The perceptual task showed that discrimination accuracies for emotional stimuli (i.e., angry and happy) were lower than those for neutral stimuli, implying that emotional information has a negative impact on early perceptual processes. Alternatively, the results of the WM task showed that the accuracy drop as the interstimulus interval increased was actually lower in emotional BM conditions than in the neutral condition, which suggests that emotional information benefited maintenance. Moreover, anger and happiness had distinct impacts on the performance of perception and WM. Our findings have significance as we provide evidence for the interaction of type of emotion and information-processing stage.

• Geophysics and Geophysical Exploration
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• v.12 no.1
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• pp.69-76
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• 2009

We report an implementation of the Ground Penetrating Radar (GPR) survey at a site that corresponds to a ruined castle. The objective of the survey was to characterise buried archaeological structures such as walls and tiles in Van Khan Tooril's Ruin, Mongolia, by 2D and 3D GPR techniques. GPR datasets were acquired in an area 10mby 9 m, with 10 cm line spacing. Two datasets were collected, using GPR with 500MHz and 800MHz frequency antennas. In this paper, we report the use of instantaneous parameters to detect archaeological targets such as tile, brick, and masonry by polarimetric GPR. Radar polarimetry is an advanced technology for extraction of target scattering characteristics. It gives us much more information about the size, shape, orientation, and surface condition of radar targets. We focused our interpretation on the strongest reflections. The image is enhanced by the use of instantaneous parameters. Judging by the shape and the width of the reflections, it is clear that moderate to high intensity response in instantaneous amplitude corresponds to brick and tiles. The instantaneous phase map gave information about the location of the targets, which appeared as discontinuities in the signal. In order to increase our ability to interpret these archaeological targets, we compared the GPR datasets acquired in two orthogonal survey directions. A good correlation is observed for the alignments of reflections when we compare the two datasets. However, more reflections appear in the north-south survey direction than in the west-east direction. This is due to the electric field orientation, which is in the horizontal plane for north-south survey directions and the horizontally polarised component of the backscattered high energy is recorded.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.482-492
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• 2019

This study began with the assumption that the phonetics-centered interpretation of 100 Chinese characters would enhance thinking ability and comprehension. For this purpose, two experimental groups and a comparative group were recruited from the graduate students from June 3, 2017 to February 22, 2018. The experimental group participated in the phonetics-centered Chinese character lecture for 4 hours per week for 6 weeks for a total of 24 hours. QEEG were measured before and after the phonetics-centered Chinese character lecture. A total of 18 subjects ( nine subjects in the experimental group and nine comparative subjects) were included in the study, and the difference between before and after the QEEG of the experimental and comparative groups was analyzed, respectively. The conclusions drawn from this study are as follows. First, the Chinese character lecture changed brain waves. Second, the LORETA analysis before and after the lecture in the experimental group significantly decreased the delta wave in the brain region (Broadmann 40) associated with the meaning of language and phonology. This study result is meaningful because it shows the significant changes of EEG via the lecture.

• Journal of Korea Water Resources Association
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• v.57 no.5
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• pp.321-332
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• 2024

Understanding the status of surface cover in riparian zones is essential for river management and flood disaster prevention. Traditional survey methods rely on expert interpretation of vegetation through vegetation mapping or indices. However, these methods are limited by their ability to accurately reflect dynamically changing river environments. Against this backdrop, this study utilized satellite imagery to apply the Random Forest method to assess the distribution of vegetation in rivers over multiple years, focusing on the Naeseong Stream as a case study. Remote sensing data from Sentinel-2 imagery were combined with ground truth data from the Naeseong Stream surface cover in 2016. The Random Forest machine learning algorithm was used to extract and train 1,000 samples per surface cover from ten predetermined sampling areas, followed by validation. A sensitivity analysis, annual surface cover analysis, and accuracy assessment were conducted to evaluate their applicability. The results showed an accuracy of 85.1% based on the validation data. Sensitivity analysis indicated the highest efficiency in 30 trees, 800 samples, and the downstream river section. Surface cover analysis accurately reflects the actual river environment. The accuracy analysis identified 14.9% boundary and internal errors, with high accuracy observed in six categories, excluding scattered and herbaceous vegetation. Although this study focused on a single river, applying the surface cover classification method to multiple rivers is necessary to obtain more accurate and comprehensive data.

• Journal of The Korean Association For Science Education
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• v.22 no.1
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• pp.40-53
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• 2002

This study was based on the analysis of earth and environmental science items in PISA 2000 data. The purpose of this study was to identify i) gender differences in scientific literacy, ii) item characteristics that favored either female or male, and iii) misconceptions that 15-years-old Korean students have in the field of earth and environmental science. The results revealed significant gender differences. Overall, male students demonstrated higher level of achievement than female students. On the other hand, amongst high ability students, female students outperformed male students in open-constructed items. Female students tended to score higher on items that required long answers or items related to scientific processes, whereas male students outperformed female students in science knowledge or items that required data interpretation. The study also revealed that a majority of Korean students had misconceptions in fundamental earth and environmental science knowledge, such as the direction of earth's axis and equator, and the causes of Greenhouse Effect.