• Biomedical Science Letters
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• v.26 no.1
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• pp.14-21
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• 2020

Quantitative evaluation of the sense of smell is done by the olfactory event-related potential (OERP) test. OERP consists of N1, P1, N2, P2, and P3, of which N1 and P1 latency are known to be affected by the concentration of odor stimuli associated with the pre-sensory phase and P2 and P3 are the stages at which odors are perceived and are known to change by subjective evaluation of the stimulus. The purpose of this study was to clarify the correlation between the expression of OERP and the subjective evaluation of the object on the fragrance stimulus using various fragrances. Therefore, the study examined the relative waveform power ratio, preference for each scent stimulus, and finally the amplitude and latency change of the components of OERP, N1 and P2. In contrast, it was found that the late P2 response waveform was an effective aroma stimulus recognition waveform in OERP compared to the initial response waveforms.

• Journal of the Ergonomics Society of Korea
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• v.25 no.4
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• pp.9-22
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• 2006

1/f fluctuation characteristics can be seen in various natural phenomena, such as breezes, streams, candle flames and the luminous patterns of fireflies. It is said that the 1/f fluctuation are comfortable for human beings. And they are introduced into many industrial products, such as an air conditioner, music, lighting, etc. This study focused on verifying the effects of 1/f fluctuation sound on comfort sensibility. Stimulus were divided into three groups(Group 1, 2, 3) by sound generation methodology. Fluctuation patterns of group 1, 2 were given by three types of fluctuation, 1/f0, 1/f1, 1/f2, and its of group 3 were given by two types of pure tone, 1/f1. In order to verify the effects, we measured the physiological responses of the subjects such as EEG(Electroencephalogram), ERP(Event-Related Potential), and these physiological responses were compared with subjective assessments, free answers. Consequently, we found that factor which had an effect on comfort sensibility was cognitive factor(for stimulus) rather than 1/f fluctuation sound pattern.

• Science of Emotion and Sensibility
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• v.18 no.2
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• pp.85-100
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• 2015

This study aimed at examining if the original memory remains after a misinformation is presented, using Event-Related Potential based Concealed Information Test (ERP-based CIT). In the first stage of the study, the participant was presented with either the original information or a misleading information after experiencing an event (Post-information). The second stage was to measure brain wave and reaction time on the original, misleading, and irrelevant information (CIT-Stimulus). P300 amplitude, P300 area, P300 latency, and reaction time were used as dependant variables. In the result, a significant Post-information ${\times}$ CIT-Stimulus interaction effect was found on the P300 area measured at Cz, Pz, and Oz area. This interaction effect implied the possibility that the original information could be partially impaired in memory by misleading information presented afterward. P300 amplitude at Pz area did not differ between the accurate and the misleading stimuli in the condition in which a misleading information was presented. This result can be explained by source monitoring error. In discussion, the limitations of this study and directions of future studies were discussed.

• Journal of Biomedical Engineering Research
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• v.43 no.1
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• pp.52-60
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• 2022

Purpose: For now, cognitive load is assessed based on survey-based methods, which can be difficult to track the amount of cognitive load in real-time. In this study, we investigated the difference in electrophysiological activation due to different levels of cognitive load not only at sensor-level but also at source-level using electroencephalogram that might be potentially used for quantitative cognitive load evaluation. Materials and Methods: In this study, ten healthy subjects (mean age 24.3 ± 2.1, three female) participated the experiment. All participants performed 4 sessions of n-back task in different difficulties: 0-, 1-, 2-, and 3-back during electroencephalogram recording. For sensor-level analysis, we calculated the event-related potential and event-related spectral perturbation while low resolution brain electromagnetic tomography (LORETA) to estimate the source activation. Each result was compared between different workload conditions using statistical analysis. Results: Statistical results revealed that the accuracy of the task performance was significantly different between different cognitive loads (p = 0.018). The post-hoc analysis confirmed that the accuracy of the 3-back task was significantly decreased compared to 1-back condition (p = 0.018), but not with 2-back condition (p = 0.180). ERP results showed that P300 target amplitude between 1-back and 3-back had a marginal difference in Cz (p = 0.059) and Pz(p = 0.093). A significant inhibition in Cz high-beta activation (p = 0.017) and decrease in source activation of right parahippocampal gyrus was found in 3-back condition compared to 1-back condition (p < 0.05). Conclusion: In this study, we compared the sensor- and source-level differences in electroencephalogram between different levels of cognitive load, that were found to be in line with the previous reports related to cognitive load evaluation. We expect that the outcome of the current study can be used as a feature to establish a quantitative cognitive load assessment system.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2001.05a
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• pp.308-312
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• 2001

본 연구에서는 사상관련전위인 수반음성변동(CNV)을 이용하여 쾌/불쾌 향의 영향을 평가하고자 하였다. 즉, 건강한 20대 성인을 대상으로 쾌한 향(레몬)과 불쾌한 향(E3) 자극에 따른 CNV의 전기성분 및 후기성분의 변화를 대뇌부위별, 가산횟수별로 비교 분석하였고, 쾌/불쾌 향의 자극 반복에 따른 주관적 평가도 부가하여 검토하였다. 그 결과, 쾌/불쾌 향은 CNV 후기성분의 중심엽 부위에서 10∼15회 가산평균의 경우 정량적으로 구별될 수 있는 가능성을 보였고, 주관적인 평가에서는 반복 자극횟수가 증가함에 따라 쾌/불쾌감이 저하하는 것을 알 수 있었다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.490-493
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• 2011

최근 사용자와 컴퓨터간의 상호작용이 가능한 사용자 인터페이스(UI, User Interface)에 대한 연구가 활발히 진행되고 있다. 이중 키보드나 마우스, 리모컨과 같은 별도의 입력장치가 없이 뇌의 활동으로부터 발생하는 생체신호를 이용하여 사용자의 생각만으로 컴퓨터와 커뮤니케이션을 할 수 있는 뇌만으로 컴퓨터와 커(BCI, Brain-Computer Interface) 시스템이 각광을 받고 있다. 본 연구에서는 뇌의 생체신호로는 뇌전도도(EEG, Electroencephalogram)를 사용하였으며, 이를 통하여 P300 speller 실험을 수행하였다. P300 speller 실험을 통하여 발생된 뇌전도도를 취합하여 P300(사건 관련 전위(ERP, Event-related potential)에서 자극 제시 약 300msec 후에 정점에 달하는 정파)을 분석하였다.

• Journal of the Ergonomics Society of Korea
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• v.13 no.2
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• pp.43-48
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• 1994

Among many kinds of odors, some are known to have effects of sedation or stimulation on brain activity. In this study, brain activity levels affected by four kinds of fragrance0lemon, lavender, jasmine, and rose-were tested using EEG recording. In the first experiment, the quality of alpha wave was examined under controlled rest condition. In the second experiment, the event-related potential (ERP) and contingent negative variation (CNV) were investigated during a simple reaction tasks (SRT) against auditory signal. EEG data obtained for the rest condition were analyzed suing "3-Dimensional Viewer)" which was developed by ourselves to show the chaotic attractor of the signal. Power spectrum were also calculated using FET. EEG data obtained during the SRT were analyzed by comparing CNV amplitudes about each odor condition. Results confirmed the sedative effect of the lemon and the lavender, and the stimulative effect of the jasmine and the rose.

• Journal of Oriental Neuropsychiatry
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• v.23 no.4
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• pp.1-10
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• 2012

Objectives : This study aims to evaluate the current status of clinical use of diagnostic equipment in oriental neuropsychiatry. Methods : Thirty clinical studies using diagnostic equipment out of 223 papers in the journal of oriental neuropsychiatry in the 10 years from 2003 to 2012 were reviewed. Results : Ten diagnostic apparatuses were used in 30 papers. HRV (Heart Rate Variability) was used the most, but the results of papers were not consistent. ADS (ADHD Diagnostic System) and ERP (Event Related Potential) were effective in clinical research. Conclusions : Diagnostic equipment might be useful and effective to treat mental disorders if they are to be used properly and followed by well-designed studies.

• Proceedings of the Korean Society of Computer Information Conference
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• 2023.07a
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• pp.357-358
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• 2023

본 연구는 실제 행동과 운동 심상으로 팔과 다리 동작 인식을 위한 BCI 패러다임을 제안하고 유도성 분석을 한다. 이 페러다임은 각 팔과 양다리의 특정 움직임을 인식하기 위해 ERP를 기반 페러다임을 구성한다. BCI 페러다임은 왼팔, 오른팔, 양다리를 움직이는 영상 자극을 주며 이를 기반으로 왼팔, 오른팔, 양다리 움직임에 대한 인식을 한다. 거울뉴런은 실제 행동과 실제 행동을 보았을때와 운동심상을 통한 자극을 받았을 때 같은 뉴런이 활성화된다는 성질을 가지고 있다. 이러한 성질을 이용하여 운동심상만과 실제 행동을 동시에 학습할 경우를 유도성 분석을 진행한다. 또한 유도성 특징 분석을 통해 나타난 결과를 바탕으로 BCI 패러다임을 제안한다.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.11 no.1
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• pp.31-38
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• 2013

Purpose : This study was to identify the effect of cognitive reaction following inactive electrode placement when applying anodal transcranial direct current stimulation over the primary motor cortex. Methods : For this study a total of 28 stroke patients participated. Before applying transcranial direct current stimulation, cognitive reaction was measured (P300 of event related potential, cognitive reaction time), and subjects were randomly assigned to two group. Transcranial direct current stimulation was applied to the scalp with an intensity of $0.04mA/cm^2$ for 15 minutes. All subjects were given an anode transcranial direct current stimulation over the primary motor area and inactive electrodes over the deltoid muscle (group I) and supra-orbital area (group II). Cognitive reactions were measured after applying transcranial direct current stimulation. Results : For this study a total of 28 stroke patients participated. Before applying transcranial direct current stimulation, cognitive reaction was measured (P300 of event related potential, cognitive reaction time), and subjects were randomly assigned to two group. Transcranial direct current stimulation was applied to the scalp with an intensity of $0.04mA/cm^2$ for 15 minutes. All subjects were given an anode transcranial direct current stimulation over the primary motor area and inactive electrodes over the deltoid muscle (group I) and supra-orbital area (group II). Cognitive reactions were measured after applying transcranial direct current stimulation. Conclusion : Thus transcranial direct current stimulation on the primary motor area may help cognitive reaction regardless of inactive electrode placement.