• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2000.06a
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• pp.260-263
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• 2000

In order to catch the relationship between psychophysiological symptoms and human work performance, the ERP technique was adopted as a measure, and two different tasks - a counting task and an Odd-Ball task were conducted. According to the results, the P300 amplitude during the counting task was not so high as that during the Odd Ball task, and correct response corresponded with stable ERP with high P300 amplitude whereas wrong response with unstable, fluctuating ERP with low P300 amplitude, Therefore it was concluded that it would be possible to grasp the symptoms of human errors with the help of psycho-physiological technique.

• Korean Journal of Cognitive Science
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• v.11 no.3_4
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• pp.83-93
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• 2000

The effect of immediate and delayed recognition memory on event-related potential (ERP) was studied using a continuous recognition memory task and event-related potential (ERP). Among 240 stimulus words 40 words were not repeated. 100 were immediately repeated and 100 were repeated after 5 intervening words. All words presented only once during the experiment were referred to as new words. Subjects responded faster and more accurately to words repeated immediately than to new words a and to those repeated after intervening words. In terms of ERP results the immediately repeated words were associated with large P300 amplitude, early P300 latency and a absence of N400. while words repeated after a delay were associated with small P300 a amplitude. late P300 latency and the presence of N400. N400 was elicited only to new w words and to those repeated after a delay. The general morphology of the waveform was s similar for three stimulus-presentation conditions until around 3l0ms after the onset of stimulus. These results indicate that immediate and delayed recognition memory could be dissociated into two distinct processes possibly being mediated by different cerebral mechanism, and the dissociation between two types of recognition memory emerges around 3l0ms poststim'ulus. The immediate and delayed recognition memory for words are considered in terms of template matching and memory searching.

• Science of Emotion and Sensibility
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• v.20 no.2
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• pp.149-160
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• 2017

In hypothesis testing, the interpretation of a statistic obtained from the data analysis relies on a probabilistic distribution of the statistic constructed according to several statistical theories. For instance, the statistical significance of a mean difference between experimental conditions is determined according to a probabilistic distribution of the mean differences (e.g., Student's t) constructed under several theoretical assumptions for population characteristics. The present study explored the logic and advantages of random-resampling approach for analyzing event-related potentials (ERPs) where a hypothesis is tested according to the distribution of empirical statistics that is constructed based on randomly resampled dataset of real measures rather than a theoretical distribution of the statistics. To motivate ERP researchers' understanding of the random-resampling approach, the present study further introduced a specific example of data analyses where a random-permutation procedure was applied according to the random-resampling principle, as well as discussing several cautions ahead of its practical application to ERP data analyses.

• Journal of Biomedical Engineering Research
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• v.30 no.4
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• pp.306-310
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• 2009

The purpose of this study is to observe the change in gamma-band cortical activities (GBAs) due to task difficulty. Event-related potential and gamma-band activity were investigated using electroencephalograms recorded during auditory oddball tasks with two difficulty levels. For more difficult task, the amplitude of P300 decreased and the peak latency of P300 was delayed significantly compared to easier task. The induced GBA decreased considerably during the P300 latency period and the peak latency of the induced GBA was delayed for more difficult task. The results imply that the difficulty-related change in cortical information processing may be implemented as a change in the strength of local neuronal association.

• Korean Journal of Biological Psychiatry
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• v.11 no.1
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• pp.40-48
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• 2004

Objective:Event-related potentials(ERPs) are electrical changes recorded at the surface of the scalp in response to stimulus presentation, and their latency and amplitude change according to cognitive processes. Through past studies of the auditory ERP in schizophrenia, the P300 has been reported to be statistically smaller and delayed in schizophrenia than comparison groups. However, studies of the visual ERP have not been systematically examined. The present study was designed to investigate the visual P300 in patients with schizophrenia and normal controls and to compare the pattern of P300 between them. Methods:The subjects were composed of patients(N=22) with schizophrenia by DSM-IV and normal controls(N=22). The visual ERPs were measured by the visual continuous performance test. P300 amplitude and latency measured on 5 scalp electrodes(Fz, Cz, Pz, $T_7$, $T_8$) were compared between patients and controls. Results:The P300 latencies measured on Fz, Cz, Pz, and $T_7$ electrodes were significantly longer in patients than controls(p<0.05). The P300 amplitudes in patients were smaller than controls. However, the difference between them was not statistically significant. Conclusion:Analysis of the visual ERPs showed that the P300 latency is significantly delayed and the P300 amplitude is slightly smaller in patients than controls. These results are similar to established studies of the auditory P300 in schizophrenia.

• Sleep Medicine and Psychophysiology
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• v.16 no.1
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• pp.16-21
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• 2009

In accordance with the development of EEG and polysomnography in the field of sleep research, the sleep onset period (SOP) between wakefulness and sleep has been considered an important part for understanding the physiology of sleep. SOP in the transition from wakefulness to sleep is a gradual process integrating various viewpoints such as behavior, EEG, physiology and subjective report. Particularly, based on understanding of EEG changes during sleep, SOP has been regarded as a pattern of topographical change in specific frequency and specific state in EEG. Studies on quantitative EEG (qEEG) and event-related potential (ERP) have suggested that SOP shows the changes of functional coordination at the specific cortical areas in qEEG and the changes of regular patterns in response to environmental stimulation in ERP. The development of sleep EEG and topographic mapping of EEG is expected to integrate various viewpoints of SOP and clarify the neurophysiologic mechanism of SOP further.

• Journal of Korea Multimedia Society
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• v.20 no.6
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• pp.950-959
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• 2017

Even though there are many studies on emotion recognition using EEG, there is a few research on specific emotion recognition in detail. In this paper, we construct test videos and conduct congruent-incongruent test for analysis on fear of crime. We compared the differences of event-related potential of subjects before and after watching the video using the congruent-incongruent test and analyzed the fear that subject perceived. Our results demonstrate that subjects showed lower amplitudes for unexpected stimuli in the PZ, POZ, and OZ electrodes of the occipital lobe, which process visual stimuli. These results indicate that the perception of subject is slower for unexpected objects.

• Proceedings of the Korean Society for Cognitive Science Conference
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• 2000.05a
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• pp.61-67
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• 2000

본고는 텍스트로 제시된 한국어 문장의 형태통사론적 오류와 의미적 논항결합시 하위범주화요건을 위배하는 논항선택 오류의 인식 및 판단에 따른 ERP(Event-Related Potential)를 검출하여, 이에 대한 문장이해과정의 시간추이적 양상을 연구의 대상으로 하였다. 참여한 피험자로부터 각각의 유형에 대한 통계분석 결과, 통사적 오류 추출에서 의미적 오류 추출에 이르기까지 기존의 연구에서 제시된 오류패턴 요소들(ELAN, N400, P600)을 확인하였으며, 아울러 한국어 문장이해과정의 특이성을 관찰할 수 있었다. 이를 통해 문장묵독시 일어나는 여러 종류의 문법오류에 대한 개별적 성격규명과 함께, 이들의 문법틀 내에서의 상호관계에 대한 일련의 가설설정이 이루어질 수 있으며, 또한 문장이해 메커니즘의 신경적 기전의 특성 규명으로 부수될 인간지능 모사가능성에 생리학적 토대가 더해 질 것으로 추정되는 바, 언어이해와 대뇌기전지형을 결정짓는 또 다른 규준이 될 것이다.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.1.1-5
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• 1994

In the single sweep record of event-related potential (ERP), the peak latency of P300, which is one of the most prominent positive peaks in the ERP record, might fluctuate according to the recording conditions. The fluctuation of the peak latency (measurement fluctuation) is the summation of the fluctuation caused by physiological factor (physiological fluctuation) and one by noise of background EEG (noise fluctuation). We propsed a method for estimating the interval of the physiological fluctuation based on a limited number of single sweep records. The noise fluctuation was estimated by using the relationship between the signal-to-noise (SN) ratio and the noise fluctuation based on the P300 model and the background EEG model. The interval estimate of the physiological fluctuation were obtained by subtracting the interval estimate of the noise fluctuation from that of the measurement fluctuation. The proposed method was tested by using simulation data of ERP and applied to actual ERP and data of normal subjects, and gave satisfactory results.

• Science of Emotion and Sensibility
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• v.16 no.4
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• pp.527-534
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• 2013

In this study, we analyzed spatial-frequency relationship related brain function for change of the time during attentional visual stimulus through the analysis of Coherence. With experimentation about ERP(Event Related Potential)data, it revealed that change of the phase synchronization between different scalp locations at ${\theta}$, ${\alpha}$ band. ERP between left and right frontal lobes, between the frontal and central lobes showed the phase synchronization at the P100, N200, ERP between the frontal and occipital lobes showed the phase synchronization at the P300 related information of visual stimulus. Compared to STFT using the window of a fixed length, CWT is able to multi-resolution analysis with the adjustment of parameters of mother wavelet. Thus, coherence results with CWT was found to be effective for analysis of time-varying spatial-frequency relationship in ERP. The phase synchronization for inattentional visual stimulus was not observed.