• Journal of KIISE
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• v.44 no.6
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• pp.587-594
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• 2017

Recently, motor imagery electroencephalogram(EEG) based Brain-Computer Interface(BCI) systems have received a significant amount of attention in various fields, including medicine and engineering. The Common Spatial Pattern(CSP) algorithm is the most commonly-used method to extract the features from motor imagery EEG. However, the CSP algorithm has limited applicability in Small-Sample Setting(SSS) situations because these situations rely on a covariance matrix. In addition, large differences in performance depend on the frequency bands that are being used. To address these problems, 4-40Hz band EEG signals are divided using nine filter-banks and Regularized CSP(R-CSP) is applied to individual frequency bands. Then, the Mutual Information-Based Individual Feature(MIBIF) algorithm is applied to the features of R-CSP for selecting discriminative features. Thereafter, selected features are used as inputs of the classifier Least Square Support Vector Machine(LS-SVM). The proposed method yielded a classification accuracy of 87.5%, 100%, 63.78%, 82.14%, and 86.11% in five subjects("aa", "al", "av", "aw", and "ay", respectively) for BCI competition III dataset IVa by using 18 channels in the vicinity of the motor area of the cerebral cortex. The proposed method improved the mean classification accuracy by 16.21%, 10.77% and 3.32% compared to the CSP, R-CSP and FBCSP, respectively The proposed method shows a particularly excellent performance in the SSS situation.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.1
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• pp.62-68
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• 2012

Steady-State Visually Evoked Potentials (SSVEP) are natural response signal associated with the visual stimuli with specific frequency. By using SSVEP, occipital lobe region is electrically activated as frequency form equivalent to stimuli frequency with bandwidth from 3.5Hz to 75Hz. In this paper, we propose an experimental paradigm for analyzing EEGs based on the properties of SSVEP. At first, an experiment is performed to extract frequency feature of EEGs that is measured from the image-based visual stimuli associated with specific objective with affordance and object-related affordance is measured by using mirror neuron system based on the frequency feature. And then, linear discriminant analysis (LDA) method is applied to perform the online classification of the objective pattern associated with the EEG-based affordance data. By using the SSVEP measurement experiment, we propose a Brain-Computer Interface (BCI) system for recognizing user's inherent intentions. The existing SSVEP application system, such as speller, is able to classify the EEG pattern based on grid image patterns and their variations. However, our proposed SSVEP-based BCI system performs object pattern classification based on the matters with a variety of shapes in input images and has higher generality than existing system.

• Journal of KIISE
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• v.44 no.9
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• pp.887-892
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• 2017

Brain-computer interface (BCI) is a technology that controls computer and transmits intention by measuring and analyzing electroencephalogram (EEG) signals generated in multi-channel during mental work. At this time, optimal EEG channel selection is necessary not only for convenience and speed of BCI but also for improvement in accuracy. The optimal channel is obtained by removing duplicate(redundant) channels or noisy channels. This paper propose a dual filter-based channel selection method to select the optimal EEG channel. The proposed method first removes duplicate channels using Spearman's rank correlation to eliminate redundancy between channels. Then, using F score, the relevance between channels and class labels is obtained, and only the top m channels are then selected. The proposed method can provide good classification accuracy by using features obtained from channels that are associated with class labels and have no duplicates. The proposed channel selection method greatly reduces the number of channels required while improving the average classification accuracy.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.211-214
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• 2008

Brain Computer Interface(BCI)분야는 뇌파를 이용하여 컴퓨터를 컨트롤 하는 기술로 최근 많은 연구가 이루어 지고 있다. 뇌파는 주변 상황과 개인, 상태에 따라 그 변화가 명확하기 때문에 BCI 분야는 앞으로 많은 응용 프로그램 개발에 충분한 자원이 될 수 있다. 기존의 BCI 연구는 뇌파를 입력 값으로 사용하여 컴퓨터를 컨트롤 하였다. 하지만 뇌파 값은 환경과 상황, 개인마다 다르기 때문에 특정 값으로 사용하기에 어려운 점이 있다. 본 논문에서는 이러한 뇌파의 특징을 이용하여 집중력을 향상시키는 개인용 게임시스템을 제안하고자 한다.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2011.05a
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• pp.37-38
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• 2011

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2001.05a
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• pp.271-275
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• 2001

두뇌-컴퓨터 인터페이스로 활용하기 위한 시도로서, 인간의 가장 간단한 의사 표시인 긍/부정 의사와 관련한 뇌파를 측정하고 시간-주파수 분석을 수행하였다. 선행 연구 결과와 뇌파 측정 실험 조건에 대해 살펴 보고, 시간-주파수 분석 결과로부터 긍/부정 반응 동작에 따른 뇌파 변화에 대해 토론하였다.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.22 no.2
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• pp.20-34
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• 2004

최근 외신을 통해서 보도된 원숭이를 이용한 BCI (Brain-Computer Interface) 실험에 관한 보도 (Carmena et al., 2003)나 배우 Keanu Reeves가 세 편에 걸쳐서 열연한 영화 Matrix를 통해서나 뇌-컴퓨터 접속이라는 주제가 대중적으로 많은 인기를 끌고 있다. 배우 KeanuReeves는 1995년에도 Fox 영화사에서 제작된 Jonny Mnemonic Superbit Collection(국내 소개명 코드명J)라는 영화에서 뇌-컴퓨터접속기술을 소개한 바 있는데 그리 큰 인길르 끌지는 못하였다가 최근 몇 년간에 걸친 Matrix 쓰리즈에서 뇌-컴퓨터 접속기술을 범대중적으로 소개하는데 성공하였다.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2011.11a
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• pp.11-12
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• 2011

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2011.11a
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• pp.78-79
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• 2011

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2002.05a
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• pp.114-117
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• 2002

뇌-컴퓨터 인터페이스로 활용하기 위한 시도로서, 인간의 가장 간단한 의사 표시인 긍/부정 의사와 관련한 뇌파를 측정하고 시간-주파수 분석(단시간 푸리에 변환)을 수행하였다. 반응 동작과 관련한 $\mu$파와 $\beta$파, 그리고 인지 정보 처리와 관련한 ${\gamma}$파의 시간에 따른 변화를 살펴보고 선행 결과들과 비교, 토론하였다.