• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1996년도 추계학술대회
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• pp.229-232
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• 1996

we propose the shrinkage of wavelet coefficients and the averaging method. The wavelet analysis decomposes the measured evoked potentials into scale coefficients and wavelet coefficients as a resolution level, respectively. And in the course of synthesis of evoked potentials, the presented method shrinks the wavelet coefficients, and then reproduces the evoked potentials and lastly averages it. we measured VEP signal to simulate the presented method, and compared it with averaged signal and LMS algorithm. As a result of simulations, the proposed method gets improved VEP about 0.2-1.6db in comparison with the result of averaging method.

• Neonatal Medicine
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• 제15권1호
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• pp.94-99
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• 2008

저자들은 저혈당증에 의해 발생한 뇌후두엽의 신생아 저혈당 뇌증과 이로 인한 시각유발전위검사 이상을 보인 2례를 경험하였기에 보고하는 바이다.

• Annals of Clinical Neurophysiology
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• 제2권1호
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• pp.13-20
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• 2000

Background and Objective : Visual evoked potentials(VEPs) is considered to be a reliable diagnostic procedure for examining patients with anterior visual pathways. Some abnormalities in the recordings on monocular stimulation have been said to indicate retrochiasmal lesion, but less consistent results have been reported. This study is to evaluate the positive predictability of VEP for the detection of retrochiasmal lesion. Methods : We reviewed VEPs that could be interpreted as indicative of a retrochiasmal lesions, based on amplitude or latency asymmetry recorded on the left(O1) and right(O2) occipital regions. Bilateral absent VEPs on both recording(O1 and O2) without evidence of prechiasmal lesion were included. During 5 years, we identified 31 patients who met the above criteria and who had undergone magnetic resonance imaging(MRI) of brain(one patient underwent computerized tomography). Twenty three patients underwent pattern reversal VEPs and others underwent flash goggle VEPs. Results : Brain imagings were abnormal in 29 and were normal in 2. Of the 29 abnormal scans, lesions in posterior visual pathway were detected in 21 scans(predictive value=68%). The predictive value was not significantly different between flash goggle VEP(75%) and pattern reversal VEP(68%). The predictive value was higher in patient with visual field defect(100%) than those without visual field defect(25%). The pathologic nature of lesion also showed close relations to the predictive value. VEPs is usually paradoxically lateralized(78%), but not in all patients. Conclusion : VEPs abnormalities suggesting retrochiasmal lesion were usually corresponded with brain MRI findings. Diagnostic reliability could be increased when considering the visual field defect and nature of lesion. Therefore, the authors suggest that VEPs studies could be useful in evaluating the patients with the retrochismal lesion.

• Journal of Nutrition and Health
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• 제31권8호
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• pp.1295-1306
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• 1998

본 연구에서는 정상으로 출생한 영아를 대상으로 DHA가 첨가된 분유 및 이유식을 섭취시켰을 때 영아의 신체발육 및 두뇌 발달에 미치는 영향을 조사하여 다음과 같은 결과를 얻었다. 1) 영아의 체중, 신장, 체위 , 두위 등 신체 발육은 소 아발육 기준치의 50th percentile에 해당하였으며. 모두 정상범위에 속하였다. 2) 혈중 총 지방질 농도는 470.4~542.9mg/dl,중성 지방은 107.0c-128.8mg/dl,총콜레스테롤 147.6-169.Omg/dl, LDL-콜레스테롤은 74.7~104.9mg/dl로 모 두 정상범위에서 군간의 유의적인 차이를 나타내지 않았다. 3) 영아의 혈중 지방산 수준을 살펴본 결과 식이 섭취 에 따른 군간의 DHA수준의 차이가 있었다. 적혈구내의 D DHA는 Breast十DHA(+) 군에서 5.26%. DHA(+ 군에서 4.20%, Breast +DHA( -) 군에서 3.98%. 그리고 DHA(-) 군에서 2.85%로 섭취에 따라유의적인 차이를 보였다. AA는 7.1O~8.93의 수준으로 군간의 차이는 없었으며. 총 n-3계 지방산은 5.82~7.75%. 총 n-6계 지방산은 27.62~30.29%의 수준으로 역시 군간에 차이가 없었다. 4) 영아의 두뇌 발달 생태를 flash VEP 검사를 통하여 실시한 결과 모든 군간의 차이가 없는 것으로 나타났다. 전기자극에 대해 가장 빨리 반응하는 시간을 나타내는 잠복기 $N_1$ 와 경우, 오른쪽 눈이 82.8~89.8ms, 왼쪽 눈이 84.8~94.4ms의 수준을 나타냈으며, 자극에 반응하는 증폭 $N_1-P_2$의 경우는 오른쪽 눈은 $-11.5~-18.3\mu\textrm{V}$, 왼쪽눈은 $-11.2~-19.1\mu\textrm{V}$, 의 수준을 나타냈다. 5) 생후 48주에 영아와 지능발달과 행동발달을 살펴 본 결과 지능 발달지수는 90.3~96.3로 정상수치라고 할 수 있는 $100\pm16$ 범위에 속하였다. 행동발달지수의 경우에도 93.9~101 수준으로 지능발달지수와 마찬가지로 정상범위에 속하였고 군간의 유의적인 차이를 관찰할 수 없었다.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1994년도 춘계공동학술대회논문집; 창원대학교; 08월 09일 Apr. 1994
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• pp.112-121
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• 1994

Studies on visual fatigues were activated after VDTs were rapidly introduced into the office works in 1980s. Various measurement methods and its measures were developed from those studies. Early studies frequently used simple measures such as near point of accommodation, near point of vergence, and CFF. Current researches focus on dark focus, dark vergence, and VEP which have a good relevance to the visual fatigues. In spite of the merit they also have some limits and disagreements. This survey summarizes the measures, measurement methods and relevant researches. Finally several topics are proposed for the future researches in Korea.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2011년도 추계학술대회
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• pp.9-10
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• 2011

• 대한의용생체공학회:의공학회지
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• 제26권2호
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• pp.95-99
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• 2005

We have performed EEG current source imaging on the cortical surface using visual evoked potentials (VEPs) recorded inside a 3.0 T MRI magnet. In order to remove ballistocardiogram (BCG) artifacts in the VEPs, an improved BCG template subtraction technique is devised. Using the cortically constrained current source imaging technique and pattern-reversal visual stimulations, we have obtained current source maps from 10 subjects. To validate the EEG current source imaging inside the magnet, we have compared the current source maps to the ones obtained outside the magnet. The experimental results demonstrate that there is a strong correspondence between the current source maps, proving that current source imaging is feasible with the evoked potentials recorded inside a 3.0 T MRI magnet.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1995년도 추계학술대회
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• pp.189-192
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• 1995

In Visually Evoked Potentials(VEP) or Auditory Evoked Potentials(AEP), the components by the stimulation and the components which are irrelevant to the stimulation(noise or nonstationary spontaneous EEG) are mixed together. So one should average hundreds of EP waves to extract the components by the stimulation only. In this study, we have classified EP's, which are the responses of the different stimulations and different states of subjects. To classify the EP waves, the cross-correlation coefficients and neural network method(error back propagation) are used and compared.

• Annals of Clinical Neurophysiology
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• 제20권1호
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• pp.12-17
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• 2018

Visual evoked potentials (VEPs) are frequently used to assess the anterior and posterior visual pathways. In particular, the use of VEPs have been increasing in various fields such as evaluation of the optic nerves in patients with multiple sclerosis. The performance of VEP test can be affected by various factors such as stimulus type and subject condition, and its interpretation is also difficult. However, there have been no guidelines for performing and interpreting VEPs in Korea. Therefore, we aimed to provide comprehensive information regarding basic requirement and interpretation for VEPs.

• 전자공학회논문지S
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• 제34S권3호
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• pp.55-62
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• 1997

For the effective removal of artifacts and the extraction of an improved evoked potential response, we propose the averaging method usin gthe shrinkag eof wavelet coefficients. The wavelet analysis decomposes the measured evoked potentials into scale coefficients with low frequency components and wavelet coefficients with high ones as a resolution level, respectively. and in the course of synthesis evoked potentials, the presented method shrinks the wavelet coefficients, and then reproduces the evoked potentials, and lastly averages it. We measured visual evoked potentials to simulate the averaging method using the shrinkage of wavelet coefficients, and compared it with aveaged signal. As a result of simulations, the proposed method gets improved VEP about 0.2-1.6dB in comparison with the averaging method with daubechies wavelet in the resolution level four.