• The Korean Journal of Physiology and Pharmacology
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• v.23 no.2
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• pp.121-130
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• 2019

Glutamate toxicity-mediated mitochondrial dysfunction and neuronal cell death are involved in the pathogenesis of several neurodegenerative diseases as well as acute brain ischemia/stroke. In this study, we investigated the neuroprotective mechanism of dieckol (DEK), one of the phlorotannins isolated from the marine brown alga Ecklonia cava, against glutamate toxicity. Primary cortical neurons ($100{\mu}M$, 24 h) and HT22 neurons (5 mM, 12 h) were stimulated with glutamate to induce glutamate toxic condition. The results demonstrated that DEK treatment significantly increased cell viability in a dose-dependent manner ($1-50{\mu}M$) and recovered morphological deterioration in glutamate-stimulated neurons. In addition, DEK strongly attenuated intracellular reactive oxygen species (ROS) levels, mitochondrial overload of $Ca^{2+}$ and ROS, mitochondrial membrane potential (${\Delta}{\Psi}_m$) disruption, adenine triphosphate depletion. DEK showed free radical scavenging activity in the cell-free system. Furthermore, DEK enhanced protein expression of heme oxygenase-1 (HO-1), an important anti-oxidant enzyme, via the nuclear translocation of nuclear factor-like 2 (Nrf2). Taken together, we conclude that DEK exerts neuroprotective activities against glutamate toxicity through its direct free radical scavenging property and the Nrf-2/HO-1 pathway activation.

• Korean Journal of Cleft Lip And Palate
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• v.10 no.2
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• pp.75-80
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• 2007

For the treatment of cleft palate patients, orthognathic surgery has been used by standard protocol. Predictable results have been achieved with standard techniques in slight to moderate maxillary hypoplasia. However, limited advancement and high relapse rate was reported in severe cases. The purpose of the present study was to review the clinical results of distraction osteogenesis in the patients with cleft lip and palate. Distraction osteogenesis has improved results in these patients by allowing soft tissue relaxation and gradual bone generation. Therefore, greater movement of the craniofacial skeleton is possible in severe cases of maxillary retrusion with lower relapse rates. In conclusion, distraction osteogenesis for the advancement of hypoplastic maxilla of cleft patients has shown successful treatment method.

• Journal of Sensor Science and Technology
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• v.26 no.2
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• pp.91-95
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• 2017

Recently, infrared (IR) spectrometers have been required in various fields such as environment, safety, mobile, automotive, and military. This IR dispersive sensor detection method of substances is widely used. In this study, we fabricated a silicon (Si) prism-based near infrared (NIR) spectrometer utilizing micro electro mechanical system (MEMS) technology. Si prism-based NIR spectrometer utilizing MEMS technology consists of upper, middle, and lower substrates. The upper substrate passes through the incident IR ray selectively. The middle substrate, acting as a prism, disperses and separates the incident IR beam. The lower substrate has an amorphous Si (a-Si)-based bolometer array to detect the IR spectrum. The fabricated Si prism-based NIR spectrometer utilizing MEMS technology has the advantage of a simple structure, easy fabrication steps, and a wide NIR region operating range.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07b
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• pp.730-732
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• 2005

디지털 방송이 본격적으로 시작되고 각 가정에 디지털 TV의 보급이 많이 이루어짐에 따라 사용자들이 시청할 수 있는 채널 및 프로그램의 수는 기존의 공중파 환경과 비교하여 폭발적으로 증가하였다. 채널의 수가 수백 개로 늘어나기 때문에 사용자가 자신이 원하는 프로그램을 찾기 위해서는 리모콘을 누르거나 방송 편성표를 검색하는 것과 같은 많은 시간과 노력을 필요하다. 따라서 이러한 문제점을 해결하기 위해서는 사용자의 프로파일과 선호도 정보를 분석하여 사용자의 취향에 적합한 프로그램을 추천해줄 수 있는 방법이 필요하다. 본 논문에서는 수백 개의 채널에서 방송되는 프로그램 및 사용자의 선호도 정보를 분석하여 사용자가 원하는 프로그램을 추천해주고 시청 히스토리를 분석하여 사용자 모델을 동적으로 갱신하는 기법을 제안한다.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06c
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• pp.319-321
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• 2006

최근 유비쿼터스 환경의 실현을 위한 핵심기술로서 RFID 시스템에 대한 연구가 활발히 진행되고 있다. 그러나 RFID 시스템이 가지고 있는 특성으로 인하여 사용자 프라이버시 침해 문제가 대두되고 있으며 이를 해결하기 위한 방법들이 개발되고 있다. 기존의 해시 체인 기법은 프라이버시를 침해하는 공격들에 대해서 가장 안전한 기법이다. 그러나 태그를 식별하기 위해서 백엔드 시스템에서의 계산량이 많다는 문제점이 있다. 따라서 본 논문에서는 이러한 확장성 문제를 해결하기 위해 해시 체인 기법 기반으로 Heilman's method를 적용하여 병행 가능한 부분을 추출한 후 각 노드별로 분할하여 적용함으로써 노드별로 수행하는 방법을 설계한다.

• 대한치주과학회:학술대회논문집
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• 2007.11a
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• pp.171-172
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• 2007

• 대한치주과학회:학술대회논문집
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• 2007.11a
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• pp.111-111
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• 2007

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1565-1568
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• 2006

An improved 3D-2D convertible display system with enhanced depth and viewing angle is proposed. By using the optical structure of an LCD panel, it is possible to enhance the performance of the system and realize the 3D-2D conversion. Some preliminary experimental results will also be provided.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.987-988
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• 2008

In this paper, we propose a rotation invariant face detection method using Haar-like feature variation. Previous approaches using rectangular features can be calculated very fast. But rectangular features is weak in rotated face. Rotated Haar-like features can get high accuracy, but the performance is slow because it can't use the integral image. Our method vary Haar-like features keeping rectangular. this method makes the performance a bit slow, but gives better accuracy.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1987-1988
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• 2008

In this study, we try to implement an image segmentation algorithm to extract only the tooth regions from the tooth color image so that we can assess the color features to estimate the status of denticulus progression.