• Journal of the Korean Society for Library and Information Science
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• v.49 no.1
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• pp.443-464
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• 2015

This study examined the feasibility of using EEG signals and ERP P3b for extracting video key-frames based on users' cognitive responses. Twenty participants were used to collect EEG signals. This research found that the average amplitude of right parietal lobe is higher than that of left parietal lobe when relevant images were shown to participants; there is a significant difference between the average amplitudes of both parietal lobes. On the other hand, the average amplitude of left parietal lobe in the case of non-relevant images is lower than that in the case of relevant images. Moreover, there is no significant difference between the average amplitudes of both parietal lobes in the case of non-relevant images. Additionally, the latency of MGFP1 and channel coherence can be also used as criteria to extract key-frames.

• Sleep Medicine and Psychophysiology
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• v.8 no.2
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• pp.121-128
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• 2001

Objectives: In narcoleptic patients diagnosed with ICSD (international classification of sleep disorders, 1990) criteria, nocturnal polysomnography, and MSLT (multiple sleep latency test), we tried to find characteristic features of quantitative electroencephalography (QEEG) in a wakeful state. Methods: We compared eight drug-free narcoleptic patients with sex- and age-matched normal controls, using computerized electroencephalographic mapping technique and spectral analysis. Absolute power, relative power, interhemispheric asymmetry, interhemispheric and intrahemispheric coherence, and mean frequency in each frequency band (delta, theta, alpha and beta) were measured and analyzed. Results: Compared with normal controls, narcoleptic patients showed decrease in monopolar interhemispheric coherence of alpha frequency bands in occipital ($O_1/O_2$), parietal ($P_3/P_4$), and temporal ($T_5/T_6$) areas and beta frequency band in the occipital ($O_1/O_2$) area. Monopolar intrahemispheric coherences of alpha frequency bands in left hemispheric areas ($T_3/T_5$, $C_3/P_3$ & $F_3/O_1$) decreased. Decrease of monopolar interhemispheric asymmetry of delta frequency band in the occipital ($O_1/O_2$) area was also noted. The monopolar absolute powers of beta frequency bands decreased in occipital ($O_2,\;O_z$) areas. Conclusion: Decreases in coherences of narcoleptic patients compared with normal controls may indicate fewer posterior neocortical interhemispheric neuronal connections, and fewer left intrahemispheric neuronal connections than normal controls in a wakeful state. Therefore, we suggest that abnormal neurophysiological sites of narcolepsy may involve complex areas such as neocortex and subcortex as well as the brainstem.

• Journal of Korean Elementary Science Education
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• v.25 no.spc5
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• pp.556-566
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• 2007

The purpose of this study was to develop an electroencephalogram (EEG) based differential-scale for scientifically gifted students in elementary school. For this study, signals of EEG with 19 channels were recorded during the generation of our scientific hypothesis using 22 scientifically gifted students, and with 49 average students being used as the control group. IQ, TCT and knowledge generation (KG) as constructs of the scientifically gifted were administered for both the scientifically gifted and the normal, control group elementary students. A 'gifted' value was added to paper test scores of the IQ, TCT, and KG constructs in order to make a personal standardization score for the gifted students. As a dependent variable, the groups were divided by means of the standardization scores thus produced and as an autonomous variable, various EEG parameters were presented through linear analysis, nonlinear analysis, and interdependency measures of the EEG. Multiple linear regression analysis was applied successfully to explain the EEG parameters and to show the characteristics of the scientifically-gifted. The discrimination analysis was administered through the results of multiple linear regression of the EEG parameters thus produced. This study represents the foundation of the development of an EEG based discriminant-scale for scientifically gifted students in elementary school, because it will be able to faithfully discriminate between scientifically-gifted and average students. The results of this study indicates that most of the EEG parameters produced can contribute to predicting the characteristics of the scientifically-gifted in that they express the degree of mutual information and the coherence of mutuality. Accordingly, mutual connectivity which appears to originate in the brain seems to the core of discrimination.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.585-594
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• 2021

This Quasi-experimental study was started under the assumption that the stress of students who participated in Buddhism and Mind Healing Lectures based on an understanding of the scriptures will be relieved through the lectures, thereby enhancing their psychological stability, thinking ability, and enhancing understanding. Stress can be confirmed through a self-report test, but in this study, quantitative EEG was measured to evaluate the stress level and secure objectivity. To this end, the difference between the 1st week as pre and 15th week as post quantitative EEG was verified for the experimental group taking the Buddhism and Mind Healing Lecture held from March to June 2019 at S University in G-gu, Seoul, and the control group who did not. The Mann Whitney U test and Wilcoxon code ranking test were used as analysis methods because the number of subjects was 14. As a result, there was a significant difference in the beta wave (F7, T3, 4, T5) and the high beta wave (F7, F8, T3, T4) in the experimental group. The coherence was also improved, while there was no significant difference in the control group. Buddhism and Mind Healing Lectures improved stress.

• Journal of Biomedical Engineering Research
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• v.41 no.1
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• pp.22-27
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• 2020

Auditory stimuli are commonly used in various electroencephalogram experiments, also in EEG-based brain-computer interface systems. However, using conventional earphones that blocks the ear canal attenuates or even blocks external environmental sound which might cause loss of crucial information from surroundings. Instead, bone-conductive earphones are able to deliver sound through vibration without blocking the ear canal. To investigate the feasibility of the bone-conductive earphones for auditory-stimuli based experiments, we compared N100 event-related potential features as well the event-related spectral perturbation and inter-trial coherence of auditory steady-state response between conventional and bone-conductive earphones. The results showed no significant differences between bone conduction and conventional earphones regardless of distinct sound pressures. This result shows that bone conductive earphones can be used for auditory experiments when the environmental sound is crucial to the user.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.11
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• pp.644-652
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• 2017

The purpose of this study was to analyze the EEG according to the elderly's tendency to be addicted to smartphone games. We compared the effects of smartphone addiction on mental health such as brain waves, sleep problems and depression through comparative analysis of asymmetry and connectivity in quantitative EEG results. The study participants were two elderly people who were addicted to smartphone game and one elderly person who did not use smartphone (Ed- to confirm: only 3 participants?!). The participant's addiction tendency of smartphone was measured by using the smartphone addiction scale and EEG (QEEG) was used for EEG analysis. The results are as follows. First, the brain waves of elderly people and smartphone non-user elderly who showed symptoms of immersion and smartphone game showed a difference in asymmetry in both opening and closing anisles. Second, there were significant differences in the openness and the anxiety of the elderly who were immersed in the mobile phone and the elderly who did not use the smartphone. Through this, it is also meaningful to explore the relationship between senile cognitive impairment and smartphone use by exploring the effect of smartphone game use on brain cognitive function through comparison of EEG analysis.

• Journal of Broadcast Engineering
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• v.27 no.5
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• pp.738-750
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• 2022

In this study, we reviewed and discussed whether auditory stimuli with short length can evoke emotion-related neurological responses. The findings implicate that if personalized sound tracks are provided to XR users based on machine learning or probability network models, user experiences in XR environment can be enhanced. We also investigated that the arousal-relaxed factor evoked by short auditory sound can make distinct patterns in functional connectivity characterized from background EEG signals. We found that coherence in the right hemisphere increases in sound-evoked arousal state, and vice versa in relaxed state. Our findings can be practically utilized in developing XR sound bio-feedback system which can provide preference sound to users for highly immersive XR experiences.

• Economic and Environmental Geology
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• v.45 no.4
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• pp.377-384
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• 2012

The main field component of the Earth's magnetic field was modeled from the tri-axial magnetometer onboard KOrean MultiPurpose SATellite-II (KOMPSAT-II) for the purpose of satellite attitude control. The model computed by the KOMPSAT-II magnetometer measurement data is compared with the International Geomagnetic Reference Field (IGRF) model of a degree of up to 13 in spherical harmonic coefficients. The previous study with KOMPSAT-I (Kim et al. 2004) indicated a good correlation of power spectrum of spherical harmonic coefficients with respect to the degree up to 5. This study, however, showed an agreement of the degree up to 8-9 of the coefficient power spectrum and a discrepancy between degrees 10 and 13. We have concluded that relevant data selection process, removal of the external field from the data in the high latitude region, an accuracy of the magnetometer all play an important role in finding a coherence with the IGRF model. This study will be extended to the secular variation model of geomagnetism if longer-period data become available.

• Economic and Environmental Geology
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• v.53 no.4
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• pp.479-489
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• 2020

A fault is a geological structure that can be a migration path or a cap rock of hydrocarbon such as oil and gas, formed from source rock. The fault is one of the main targets of seismic exploration to find reservoirs in which hydrocarbon have accumulated. However, conventional fault detection methods using lateral discontinuity in seismic data such as semblance, coherence, variance, gradient magnitude and fault likelihood, have problem that professional interpreters have to invest lots of time and computational costs. Therefore, many researchers are conducting various studies to save computational costs and time for fault interpretation, and machine learning technologies attracted attention recently. Among various machine learning technologies, many researchers are conducting fault interpretation studies using the support vector machine, multi-layer perceptron, deep neural networks and convolutional neural networks algorithms. Especially, researchers use not only their own convolution networks but also proven networks in image processing to predict fault locations and fault information such as strike and dip. In this paper, by investigating and analyzing these studies, we found that the convolutional neural networks based on the U-Net from image processing is the most effective one for fault detection and interpretation. Further studies can expect better results from fault detection and interpretation using the convolutional neural networks along with transfer learning and data augmentation.

• Economic and Environmental Geology
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• v.45 no.6
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• pp.685-695
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• 2012

We studied the detailed bathymetry and the geophysical characteristics of the summit of the Dokdo volcano using mutibeam echosounding and geophysical survey data. The bathymetry around the main east and west islets of the Dokdo volcano shows very shallow within about 10 m water depth. From near islets to about 30 m b.s.l., the shallow water area has very steep slope and many irregular sunken rocks. The area from about 30 m to about 80 m b.s.l. shows gentle rises and falls, and less steep slope. The area from 80 m b.s.l. has gradually flat undulation and smooth slope seabaed and is extended to offshore. The main islets of the Dokdo volcano and the rocky sea bottom elongated from the islets might be the residual part of the eroded and collapsed main crater of the Dokdo volcano. The bathymetry and the seafloor image(from backscattering) data show small craters, assumed to be formed by the eruption of later volcanism. The seafloor images propose that, except some areas with shallow sand sedimentary deposits, there are typical rocky bottom such as rocky protrusions and lack of sediments in the main morphology of the survey area. The stepped slopes of the seabed are deduced to be submarine terraces. The several prominent submarine terraces are found at the summit of the Dokdo volcano, suggesting repetition of sea level changes(transgressions and regressions) in the Quaternary. The results of the magnetic anomaly and the analytic signal have a good coherence with other geophysical consequences regarding to the location of the residual crater.