• Proceedings of the KIEE Conference
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• summer
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• pp.372-374
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• 2004

22.9kV 가공배전선은 여러 요소들로 구성되기 때문에 뇌격에 대한 반응도 단순하지 않다. 현재의 절연협조는 대표적인 선로모델에 패한 선로상수, 접지저항 등의 대표 값을 사용하여 EMTP로 계산한 뇌충격과전압 값을 근거로 하고 있다. 절연협조 수준에 따라 경제성이 결정되고 계산에 의한 모델해석결과는 실제의 현상과 많은 차이를 나타낼 수 있음에도 불구하고 현재의 기준은 계산과정에서 사용되는 모델과 특성 값의 유효성을 확인하는 수준에 머물고 있다. 이 연구에서는 ICG로 충격전류를 인가하여 여러 가지 경우에 애자 양단에 인가되는 과전압을 실측하였다. 실측 결과 접지특성은 애자에 인가되는 과전압에 많은 영향을 미치지 않는다는 것을 알 수 있었다.

• KIPS Transactions on Software and Data Engineering
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• v.3 no.10
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• pp.421-428
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• 2014

Like Alzheimer's disease, Parkinson's Disease(PD) is one of the most common neurodegenerative brain disorders. PD results from the deterioration of dopaminergic neurons in the brain region called the substantia nigra. Currently there is no cure for PD, but diagnosing in its early stage is important to provide treatments for relieving the symptoms and maintaining quality of life. Unlike many diagnosis methods of PD which use a single biomarker, we developed a diagnosis method that uses both biochemical biomarkers and imaging biomarkers. Our method uses ${\alpha}$-synuclein protein levels in the cerebrospinal fluid and diffusion tensor images(DTI). It achieved an accuracy over 91.3% in the 10-fold cross validation, and the best accuracy of 72% in an independent testing, which suggests a possibility for early detection of PD. We also analyzed the characteristics of the brain fiber pathways of Parkinson's disease patients and normal elderly people.

• Korean Journal of Food Science and Technology
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• v.51 no.2
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• pp.160-168
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• 2019

This study aimed to determine whether double-processed ginseng berry extract (PGBC) could improve learning and memory in an $A\hat{a}42$-induced Alzheimer's mouse model. Passive avoidance test (PAT) and Morris water-maze test (MWMT) were performed after mice were treated with PGBC, followed by acetylcholine (ACh) measurement and glial fibrillary acidic protein (GFAP) detection for brain damage. Furthermore, acetylcholinesterase (AChE) activity and choline acetyltransferase (ChAT) expression were analyzed using Ellman's and qPCR assays, respectively. Results demonstrated that PGBC contained a high amount of ginsenosides (Re, Rd, and Rg3), which are responsible for the clearance of $A{\hat{a}} 42$. They also helped to significantly improve PAT and MWMT performance in the $A{\hat{a}} 42-induced$ Alzheimer's mouse model when compared to the normal group. Interestingly, ACh and ChAT were remarkably upregulated and AChE activities were significantly inhibited, suggesting PGBC to be a palliative adjuvant for treating Alzheimer's disease. Altogether, PGBC was found to play a positive role in improving cognitive abilities. Thus, it could be a new alternative solution for alleviating Alzheimer's disease symptoms.

• Journal of Yeungnam Medical Science
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• v.12 no.2
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• pp.260-268
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• 1995

Ischemia results when the decrease in tissue perfusion exceeds the tissues ability to increase an oxygen extraction from the blood. Brain edema has been defined as an abnormal accumulation of fluid within brain parenchyma associated with a volumetric enlargement of the brain tissue. In most instances, the labelling of edema as vasogenic or cytotoxic is only relative. For cerebral protection, there were many possible techniques which could increase or maintain cerebral perfusion and reduce cerebral metabolic demand for oxygen. This study was carried out the effect of mild brain hypothermia which was induced by infusion with cold saline into the carotid artery, during brief episodes of transient global ischemia on postischemic brain edema in rabbit. Eight rabbits were anesthetized with halothane and mechanically ventilated with oxygen. For isolated cerebral perfusion, polyethylene catheter was inserted left carotid artery for infusion of cold saline, external carotid artery was ligated, vertebral arteries were cautherized, right carotid artery was snared for ischemia and femoral artery and vein were also canulated for monitoring and drug treatment. At 3 hours After transient global ischemia, specific gravity of cerebral cortex and hippocampus was compared with no-perfusion group , perfusion with cold saline group and normal group. There was no significant differences in physiologic variables among the groups before transient global ischemia. But during transient global ischemia, brain temperature of perfusion group was decreased when compared to no perfusion group. Specific gravity of cerebral cortex and hippocampus of no-perfusion group and perfusion group was statistically significant when compared to normal group (p<0.01). The results of this study suggested that mild brain hypothermia with intracarotid cold saline infusion during brief episodes of transient global ischemia had decreased postischemic brain edema in rabbit.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.47 no.5
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• pp.18-23
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• 2010

In this paper, we propose a computationally efficient method detecting the P300 wave for brain-machine interface. Electrophysiological researches have shown that the P300 wave's potential is decreased when human intention matches visual stimulation. Motivated by this fact, we can infer human intention for brain-machine interface by detecting the P300 wave's potential decrease. The P300 wave is recorded from EEG(electroencephalogram) electrodes attached on human brain skull after giving alphabetical stimulation. To detect the potential decrease in P300, firstly we statistically model the P300 wave's negative potential. Then we infer human intention based on maximum likelihood estimation. The proposed method was evaluated on the data recorded from three healthy human subjects. The method achieved an averaging accuracy of 98% from subject k, 90% from subject j and 79.8% from subject h.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.04a
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• pp.95-95
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• 1995

뇌신경 변성 / 퇴행과 관련된 중요한 병인론 중의 하나는 변성 과정에서 형성된 유리기(free radical)로 인한 항산화계의 평형 소실로 알려져 있다. Aspalatone (APT)의 예상되는 항산화 효능을 검정하기 위하여 본 실험에서는 Kainic acid (KA) 유발 뇌변성 모델을 적용하였다. KA 모델은 변연계의 간질성 경련과 신경세포 변성에 대하여 재현성 있는 병변 모델을 제공해 주며, 이와 같은 신경세포의 병독 기전에 산소 유리기가 관여함이 강력히 시사되고 있기 때문이다. KA 투여로 인하여 지속적이고도 전형적인 간질성 경련이 관찰되고 1일 이내에 높은 치사율을 보였으나 APT으로 인하여 그 간질성 경련 행위와 비율이 억제되고 KA 유발 치사율도 억제되었다. 최종 KA 투여 3일 후에 얻어진 흰쥐 해마 및 대뇌 피질에서 항산화 효소인 Superoxide dismutase (SOD), Catalase (Cat.), Glutathione peroxidase (GSH-PX) 및 과산화지질의 지표인 Malondialdehyde (MDA)를 검정하였다. 대조군에 비하여 KA는 뇌조직의 SOD-1을 유도하였으나, Cat.와 GSH-PX의 활성은 현저히 유도되지 않았고, 반면에 MDA 치는 현저히 증가하였다. 즉, Cat., GSH-PX와 같은 $H_2O$$_2$중화제가 동반 유도하지 않는 SOD의 유도는 세포내 축적되는 $H_2O$$_2$로 인하여 Fenton/Haber-Weiss 반응을 가속화하여 과산화지질화를 촉진함을 시사한다. APT 병용 투여로 SOD는 현저히 유도되지 않았으나 특히 Cat.가 현저히 유도되어지고 MDA는 억제되었다. 이와 같은 생화학적인 결과는 다음의 형태학적인 소견과 일치한다. Fos 관련 항원 (FRA)와 SOD-1을 면역세포화학 (Immunocytochemistry)적 방법으로 이중 표식 (double-labelling) 하였다. FRA는 KA로 인한 신경세포의 자극에 대한 지표로 응용하였고, SOD-1은 퇴행성 뇌질환에서 산화적 손상의 지표로 사용하였다. KA 투여로 해마의 dentate gyrus (DG) 내에 강한 면역환성 (immunoreactivity)이 나타났고 pyramidal cell layer (PCL)와 glia에 SOD-1이 강하게 염색되었다. APT 병용 투여로 상당수의 경련이 일어나지 않은 흰쥐는 해마의 DG에 FRA가 경미하게 염색되었고, PCL에 SOD-1도 경미하게 나타났으나, 경련이 나타난 쥐에서는 KA만을 투여한 흰쥐와 구별되지 않았다. 이상의 APT의 항산화 효과는 KA로 인한 뇌세포 변성 개선에 중요한 인자로 작용할 것으로 사료되나, 보다 명확한 APT의 기전을 검색하고 직접 임상에 응응하기 위하여는 보다 다양한 실험 조건이 보완되어야 찰 것으로 생각된다.

• Journal of the Korea Society of Computer and Information
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• v.26 no.7
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• pp.37-44
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• 2021

Automatic classification of brain MRI images play an important role in early diagnosis of brain tumors. In this work, we present a deep learning-based brain tumor classification model in MRI images using ensemble of deep features. In our proposed framework, three different deep features from brain MR image are extracted using three different pre-trained models. After that, the extracted deep features are fed to the classification module. In the classification module, the three different deep features are first fed into the fully-connected layers individually to reduce the dimension of the features. After that, the output features from the fully-connected layers are concatenated and fed into the fully-connected layer to predict the final output. To evaluate our proposed model, we use openly accessible brain MRI dataset from web. Experimental results show that our proposed model outperforms other machine learning-based models.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.4 s.56
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• pp.93-97
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• 2005

본 실험은 휴대전화기 사용중 발생한 낙뢰 사고에 대한 원인으로 논란이 되고 있는 휴대전화기의 전자파와 낙뢰와의 상관관계를 규명하기 위한 것으로, 모의 낙뢰 발생기인 뇌 임펄스 발생기를 사용하여 인체 모델에 뇌 임펄스를 인가시 휴대전화기에 의한 유뢰의 가능 여부를 규명하기 위한 것이다.

• Journal for History of Mathematics
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• v.22 no.3
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• pp.31-44
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• 2009

Anyone wishing to understand cognitive science, a converging science, need to become familiar with three major mathematical landmarks: Turing machines, Neural networks, and $G\ddot{o}del's$ incompleteness theorems. The present paper aims to explore the mathematical foundations of cognitive science, focusing especially on these historical landmarks. We begin by considering cognitive science as a metamathematics. The following parts addresses two mathematical models for cognitive systems; Turing machines as the computer system and Neural networks as the brain system. The last part investigates $G\ddot{o}del's$ achievements in cognitive science and its implications for the future of cognitive science.

• Proceedings of the KSAR Conference
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• 2004.06a
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• pp.271-271
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• 2004

본 실험은 TGF-a를 처리하여 분화가 유도된 인간배아 줄기세포를 파킨슨 동물모델에 이식하여 숙주세포에서의 생존 및 이식효과를 검토하고자 실시하였다. TGF-a로 분화된 세포의 이식효과를 판정하고자 배양시 TGF-a처리군과 처리하지 않은 군으로 나누어 분화를 유도한 인간배아 줄기세포를 hoechst33342로 표지 하여 병변 유발과 동일한 방법으로 동측 선조체내에 4×10⁴개/2ul가 되도록 이식하고(이식 위치: AP 0.7, ML 2.0, DV3.4) 이식 후 2, 4주에서 행동학적 변화를 관찰하고 4주에 동물을 희생시켜 4% PFA를 이용하여 뇌 조직을 고정하고 뇌 조직은 40㎛ 두께로 동결 절편을 만들어 면역조직화학염색을 시행하여 신경세포로의 분화 및 TH 발현 여부를 관찰하였고 분화의 표지물질로 nestin, NF200, GFAP, TH를 사용하여 형태학적 변화를 관찰하였다. (중략)