• 융합신호처리학회논문지
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• 제8권3호
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• pp.178-184
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• 2007

일반적으로 EEG 신호는 Alpha파, Beta파, Theta파, Delta파로 구분할 수 있다. Alpha파는 사람에게 있어서 가장 우세한 파형으로써 정신적으로 안정 시 잘 나타나는 뇌파이며, Beta파는 흥분 시 우세하게 나타난다. 본 연구에서는 EEG의 안정 상태를 정량적으로 나타내기 위해 웨이브렛 변환과 파워 스펙트럼 분석을 이용하였다. EEG신호를 웨이브렛 변환을 통해 Alpha파와 Beta파만 검출하여 고속 푸리에 변환을 이용 Alpha파와 Beta파의 파워 스펙트럼을 구하였다. 이후 Beta파의 파워 스펙트럼에 대한 Alpha파의 파워 스펙트럼 비율로 정의되는 상대적 안정상태비(Stable State Ratio)를 계산하였다. 그 결과 피험자가 정상적인 활동 상태에서 정신적으로 편안한 안정 상태에 이르기까지 5분 이내가 16%, $5{\sim}10$분 사이가 9%, 그리고 최소 10분 이상의 시간이 소요되는 피험자집단이 총 69%로 우세하게 나타났다.

• 한국지능시스템학회논문지
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• 제10권4호
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• pp.304-309
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• 2000

인간의 뇌 정보처리를 이해하기 위한 일환으로서, 많은 연구자들이 사람의 두피에서 자발적으로 발생하는 전기 활동인 뇌파(EEG)를 분석하였다. 측정된 뇌파는 잠음처럼 보이는 비선형적인 거동으로 인하여 단순한 관찰만으로 그 특징을 분석하기가 매우 어렵다. 따라서 이러한 뇌파를 분석하고 이해하기 위한 방법으로 파워스펙트럼, 바이스펙트럼 등과 같은 스펙트럼 분석과 상관차원, 프랙탈 차원과 같은 비선형 카오스 분석 등과 같은 해석법들이 활발히 연구되어왔다. 본 논문에서는 이러한 기존의 방법 외에 두 신호사이의 통계적 의존성을 측정하는 양인 상호정보를 이용하여 뇌파의 특징을 분석하였다. 뇌파간의 상호정보 분석을 통해 두뇌에서의 정보의 흐름에 관한 특징을 알아보았고, 감선자극에 반응하는 두뇌의 활동영역을 알 수 있었다.

• 대한의용생체공학회:의공학회지
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• 제22권5호
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• pp.425-430
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• 2001

이 연구의 목적은 선형적 주파수 분석방법으로는 구별되지 않는 감정상태와 인지상태의 EEG를 구별할 수 있는 새로운 방법을 제안하는 것이다. 건강한 피험자들의 EEG를 세가지 다른 조건-눈을 감고 편안히 쉬고 있는 상태. 음악을 듣고 있는 상태 눈을 감고 단순한 뺄셈 연산을 수행하고 있는 상태-에서 각각 측정하였다. 점관점 상관타원 (PD2) 방법을 이용하여 각 정신상태에 따른 EEG를 분석하였다. 연산과제를 집중해서 수행했다고 보고한 집단이 그렇지 않다고 보고한 집단보다 더 높은 PD2 값을 통계적으로 유의하게 나타내었다. 또한 음악을 듣는 과제에서 높은 점수를 얻은 집단이 그렇지 않은 집단에 비해 상대적으로 낮은 PD2 값을 나타내었다. 같은 EEG 신호에 선형 분석 방법인 주파수 분석 방법을 적용하여 보았으나, 유의한 차이를 보이지 않았다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1993년도 추계학술대회
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• pp.156-159
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• 1993

In this paper, computerized BEAM (brain electrical activity map) was implemented for objective and quantitative multichannel EEG analysis. BEAM is calculated by 4 point Interpolation method and number of elements are 5140. Representation methods of BEAH are two. One is dot density method which classify brain electrical potential 9 levels by dot density and the other is color method which classify brain electrical 12 levers by different colors. In this BEAM, instantaneous change and average energy distribution over any arbitrary time interval of brain electrical activity could be observed and analyzed easily.

• ETRI Journal
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• 제42권6호
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• pp.932-942
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• 2020

To recover the neural activity from Magnetoencephalography (MEG) and Electroencephalography (EEG) measurements, we need to solve the inverse problem by utilizing the relation between dipole sources and the data generated by dipolar sources. In this study, we propose a new approach based on the implementation of a particle filter (PF) that uses minimum sampling variance resampling methodology to track the neural dipole sources of cerebral activity. We use this approach for the EEG data and demonstrate that it can naturally estimate the sources more precisely than the traditional systematic resampling scheme in PFs.

• 대한의용생체공학회:의공학회지
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• 제28권4호
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• pp.461-470
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• 2007

Human can learn how to shape their brain electrical activity in a desired direction through continuous feedback of the electroencephalogram (EEG), and this technique is known as Neurofeedback (or EEG biofeedback), which has been used since the late 1960s in clinical applications. In this study, a portable wireless EEG (named wEEG) has been designed and implemented, which consists of a mobile station (a wireless two-channel EEG acquisition device) and a base station (a bridge between mobile station and computer). Moreover, a SensoriMotor Rhythm (SMR) training system was also implemented with the wEEG for enhancing attention with virtual environment. Experiment results based on 16 volunteers' (8 females and 8 males, average age is $27{\pm}4$) were reported in this paper. The results show that the SMR ratio of 87.5% subjects increased about 0.7% in training status than that in the stable status. With the proposed system, many training protocol scan be designed easily and can be done at home in our daily life conveniently. Additionally, the proposed system will be useful for disabled and aged people.

• 감성과학
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• 제6권1호
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• pp.47-53
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• 2003

본 연구는 특성(trait) 이론에 기반한 Eysenck의 EPQ-R 설문지와 EEG 변수들간의 상관 관계에 대한 실험적 연구로서, 피험자들은 한국판 EPQ-R 설문지를 작성하였고, 2회에 걸쳐 눈을 감은 조건, 눈을 뜬 조건, 암산과제 수행조건에서 EEG를 측정하였다. Neuroticism 은 눈을 뜬 조건에서 theta 파와 부적 상관을 보였으며, Psychoticism 은 눈을 감은 조건에서 alpha파와 정적상관, delta파와 부적 상관을 보였는데, 이것은 Robinson(2001)의 이론과 일치하는 결과이다.

• The Journal of Korean Physical Therapy
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• 제28권6호
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• pp.398-407
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• 2016

Purpose: The purpose of this study was to examine the changes in electroencephalogram (EEG) coherence and brain wave activity for first-person perspective action observation (1AO) and third-person perspective action observation (3AO) of healthy subjects. Methods: Thirty healthy subjects participated in this study. EEG was simultaneously recorded during the Relax period, the 1AO, and the 3AO, with event-related desynchronization (ERD) and coherence connectivity process calculations for brain wave (alpha, beta and mu) rhythms in relation to the baseline. Results: Participants showed increased coherence in beta wave activity in the frontal and central areas (p<0.05), during the 1AO using right-hand activity. Conversely, the coherence of the alpha wave decreased statistically significantly decreased in the frontocentral and parieto-occipital networks during the observation of the 1AO and the 3AO. The ERD values were larger than 40% for both central regions but were slightly higher for the C4 central region. The high relative power of the alpha wave during 1AO and 3AO was statistically significantly decreased in the frontal, central, parietal, and occipital regions. However, the relative power of the beta wave during 1AO and 3AO was statistically significantly increased in the parietal and occipital regions. Especially during 1AO, the relative power of the beta wave in the C3 area was statistically significantly increased (p<0.05). Conclusion: These findings suggest that 1AO and 3AO action observations are relevant to modifications of specific brain wave coherence and ERD values. EEG cortical activity during action observation may contribute to neural reorganization and to adaptive neuroplasticity in clinical intervention.

• Physical Therapy Rehabilitation Science
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• 제6권4호
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• pp.164-169
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• 2017

Objective: This research investigated the effects of simple visual imagery and mental rotation imagery on neural activity of adults who are at high risk of smart phone addiction by measuring their electroencephalography (EEG). Design: Cross-sectional study. Methods: Thirty people with a high risk of smart phone addiction was selected and then were evaluated for their neural activation patterns using EEG after reminding them about simple visual imagery and mental rotation imagery. A simple visual image was applied for 20 seconds using a smartphone. This was followed by a resting period of 20 seconds. Mental rotation imagery was applied for 20 seconds. During mental rotation imagery, the rotational angle was selected at random. We compared activation patterns according to the analyzed EEG with hemisphere reminding them about imagery. Results: On the EEG, theta rhythm from the left hemisphere parietal area increased when the subjects were reminded of mental rotation imagery, and sensorimotor rhythm from close to the left hemisphere area increased when the subjects were reminded of simple visual imagery. Conclusions: Neural activation from the left hemisphere occurs for motor imagery in adults who are at high risk of smart phone addiction. These results identify a neural mechanism of adults who a have high risk of smart phone addiction, which may provide contribute to the development of motor rehabilitation for smartphone users.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2001년도 춘계학술대회 논문집
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• pp.225-230
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• 2001

Intensity of background noise is a factor significantly affecting both subjective evaluation of experienced stress level and associated electroencephalographic (EEG) responses during mental load in noisy environments. In the study on 27 subjects we analyzed the influence of the background white noise (WN) intensity on psychophysiological responses during a word recognition test. Electrocortical activity were recorded during baseline resting state and 40 s long performance on 3 similar Korean word recognition tests with different intensities of background WN (55, 70 and 85 dB).. An important finding in terms of physiological reactivity was similarity of all physiological response profiles between 55 and 70dB WN, i.e., none of physiological variables differentiated the two conditions, while 85dB WN resulted in a significantly different profile of reactions (higher fast beta power in EEG spectra). This condition was characterized by highest subjective rating of experienced stress, had more fast beta activity and had tendency of right hemisphere dominance, emphasizing the role of brain lateralization in negative affect control.