• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 추계학술대회
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• pp.201-205
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• 1997

With the recent advance of Web and its associated technologies, information sharing on distribute computing environments has gained a great amount of attention from many researchers in many application areas, such as medicine, engineering, and business. One basic requirement of distributed medical consultation systems is that geographically dispersed, disparate participants are allowed to exchange information readily with each other. Such software also needs to be supported on a broad range of computer platforms to increase the software's accessibility. In this paper, the development of world-wide-web based medical consultation system or radiology imaging is addressed to provide the platform independence and great accessibility. The system supports sharing of 3-dimensional objects. We use VRML (Virtual Reality Modeling Language), which is the de-facto standard in 3-D modeling on the Web. 3-D objects are reconstructed from CT or MRI volume data using a VRML format, which can be viewed and manipulated easily in Web-browsers with a VRML plug-in. A Marching cubes method is used in the transformation of scanned volume data set to polygonal surfaces of VRML. A decimation algorithm is adopted to reduce the number of meshes in the resulting VRML file. 3-D volume data are often very large-sized, and hence loading the data on PC level computers requires a significant reduction of the size of the data, while minimizing the loss of the original shape information. This is also important to decrease network delays. A prototype system has been implemented (http://netopia.snu.ac.kr/-cyber/). and several sessions of experiments are carried out.

• 대한의용생체공학회:의공학회지
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• 제39권1호
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• pp.43-47
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• 2018

Traditional electroencephalography (EEG)-based authentication systems generally use external stimuli that require user attention and relatively long time for authentication. The aim of this study is to investigate the feasibility of biometric authentication based on EEG without using any external stimuli. Seventeen subjects took part in the experiment and their EEGs were measured while repetitively closing and opening their eyes. For identifying each subject, we calculated inter- and intra-subject cross-correlation using changes in alpha activity (8-13 Hz) during eyes closed as compared to eyes open. In order to optimize the number of recording electrodes, we calculated authentication accuracy by progressively reducing the number of electrodes used in the analysis. Significant increase in alpha activity was observed for all subjects during eyes closed, focusing on occipital areas, and spatial patterns of changed alpha activity were considerably different between the subjects. A mean authentication accuracy of 92.45% was obtained, which was retained over 75% when using only 8 electrodes placed around occipital areas. Our results could demonstrate the feasibility of the proposed novel authentication method based on resting state EEGs.

• 대한의용생체공학회:의공학회지
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• 제41권3호
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• pp.121-127
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• 2020

The purpose of this paper is to review the validation on the application of low frequency IMU(Inertial Measurement Unit) sensors by replacing high frequency motion analysis systems. Using an infrared-based 3D motion analysis system and IMU sensors (22 Hz) simultaneously, the gait cycle and knee flexion angle were measured. And the accuracy of each gait parameter was compared according to the statistical analysis method. The Bland-Altman plot analysis method was used to verify whether proper accuracy can be obtained when extracting gait parameters with low frequency sensors. As a result of the study, the use of the new gait assessment system was able to identify adequate accuracy in the measurement of cadence and stance phase. In addition, if the number of gait cycles is increased and the results of body anthropometric measurements are reflected in the gait analysis algorithm, is expected to improve accuracy in step length, walking speed, and range of motion measurements. The suggested gait assessment system is expected to make gait analysis more convenient. Furthermore, it will provide patients more accurate assessment and customized rehabilitation program through the quantitative data driven results.

• 공업화학
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• 제1권2호
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• pp.107-115
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• 1990

Glucose의 redox 반응에 의한 새로운 인슐린 방출계를 5, 5'-dithiobis(2-nitrobcnzoic acid)의 disulfide 결합을 이용해 인슐린을 pmma 막과 glucose oxidase에 고정화시켜 합성하였다. glucose와 glucose dehydrogenase 및 glucose oxidise와의 산화반응에 의해 disulfide 결합이 파괴되어 막과 효소로부터 인슐린이 방출된다. enzyme cofact들(nicotinamide adenin dinucleotide와 flavin adenin dinucleotide)을 coimmobilization 시켜 membrane device에 대해 electron mediator로 작용하도록 하여 glucose의 농도 민감성을 향상시켰고 protein device에 대해서는 glucose oxidase에 인슐린을 직접 고정화시켜 민감성을 더욱 향상시켰다. 이 두 가지 계들은 glucose 특이성을 나타내며 방출된 인슐린은 생체인슐린과 구분되지 않았다. 방출인슐린의 생리활성은 생체인슐린의 81%였다.

• 동의생리병리학회지
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• 제24권3호
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• pp.416-425
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• 2010

The object of this study was to observe the protective effects of Yijin-tang-gamibang (YJGMB), Yijin-tang has been traditionally used in the Korean Medicine for treating various digestive diseases. The study showed that it is effective on reflux esophagitis induced by pylorus and forestomach ligation in rats. Three different dosages of YJGMB extracts, 200, 100 and 50 mg/kg, were orally pretreated, once a day for 28 days before pylorus and forestomach ligation. Seven groups, each of 8 rats per group were used in the present study. The results were compared with omeprazole, antioxidant and proton pump inhibitor, 30 and 10 mg/kg treated group. YJGMB 200 mg/kg were showed similar protective effects as compared with 30 mg/kg of omeprazole but more favorable effects were observed in 200, 100 and 50 mg/kg of all YJGMB treated rats as compared with omeprazole 10 mg/kg in the present study. In addition, YJGMB 200 mg/kg were showed more favorable antioxidant effects as compared with 30 mg/kg of omeprazole in the present study. Detail mechanism studies should be conduced in future with the screening of the biological active chemical compounds in herbs.

• 한국물환경학회지
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• 제26권1호
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• pp.61-70
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• 2010

The increase of impervious cover (IC) in a watershed is known as an important factor causing alteration of water cycle, deterioration of water quality and biological communities of urban streams. The study objective was to assess the impact of IC changes on the surface runoff characteristics of Kap Stream basin located in Geum river basin (Korea) using the Storm Water Management Model (SWMM). SWMM was calibrated and verified using the flow data observed at outlet of the watershed with 8 days interval in 2007 and 2008. According to the analysis of Landsat satellite imagery data every 5 years from 1975 to 2000, the IC of the watershed has linearly increased from 4.9% to 10.5% during last 25 years. The validated model was applied to simulate the runoff flow rates from the watershed with different IC rates every five years using the climate forcing data of 2007 and 2008. The simulation results indicated that the increase of IC area in the watershed has resulted in the increase of peak runoff and reduction of travel time during flood events. The flood flow ($Q_{95}$) and normal flow ($Q_{180}$) rates of Kap Stream increased with the IC rate. However, the low flow ($Q_{275}$) and drought flow ($Q_{355}$) rates showed no significant difference. Thus the subsurface flow simulation algorithm of the model needs to be revisited for better assessment of the impact of impervious cover on the long-term runoff process.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.202-202
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• 2011

The research of 3-dimensional (3-D) scaffold for tissue engineering has been widely investigated as the importance of the 3-D scaffold increased. 3-D scaffold is needed to support for cells to proliferate and maintain their biological functions. Furthermore, its architecture defines the shape of the new bone and cartilage growth. Polycaprolactone (PCL) has been one of the most promising materials for fabricating 3-D scaffold owing to its excellent mechanical property and biocompatibility. However, there are practical problems for using it, in vitro and in vivo; extracellular matrix components and nutrients cannot penetrate into the inner space of scaffold, due to its hydrophobic property, and thus cell seeding and attachment onto the inner surface remain as a challenge. Thus, the surface modification strategy of 3-D PCL scaffold is prerequisite for successful tissue engineering. Herein, we utilized a mussel-inspired approach for surface modification of 3-D PCL scaffold. Modification of 3-D PCL scaffolds was carried out by simple immersion of scaffolds into the dopamine solution and stimulated body fluid, and as a result, hydroxyapatite-immobilized 3-D PCL scaffolds were obtained. After surface modification, the wettability of 3-D PCL scaffold was considerably changed, and infiltration of the pre-osteoblastic cells into the 3-D scaffold followed by the attachment onto the surface was successfully achieved.

• Applied Microscopy
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• 제41권3호
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• pp.147-154
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• 2011

후방산란전자(BSE)는 입사전자빔이 시료와 충돌하면서 발생한다. BSE 이미징은 시료의 화학적 특성을 구분할 수 있는 조성대비를 제공한다. 집속이온빔장치(FIB)는 전계방사형 주사전자현미경(FESEM)과 결합할 수 있으므로 이중빔 체계(FIB-FESEM)가 구현된다. 갈륨(Ga) 이온빔으로 10~100 nm 두께로 시료를 절삭할 수 있으므로 FIB-FESEM은 플라스틱으로 포매된 블록의 면을 z축 고해상도를 유지하며 연속적으로 이미징할 수 있다. BSE이미지의 대비를 반전시키면 투과전자현미경의 이미지와 유사하다. 연속블록면 이미징의 또 다른 방안으로써 특수한 초박절편기가 FESEM 내부에 장착된 것이 $3View^{(R)}$로 상용화되어 있다. 이로써 플라스틱으로 포매된 시료의 내부 구조를 넓은 면적을 연속적으로 이미징 할 수 있으므로 3차원 재구성도 용이하게 된다. 이러한 FESEM에 기반한 두 가지 방식은 복잡한 생물계의 총체적인 이해를 위하여 세포 및 세포 수준 이하의 구조물 간의 공간적 연관성을 규명하는 데 활용될 수 있다.

• 수산해양기술연구
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• 제55권4호
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• pp.378-391
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• 2019

The objective of this study is to establish a direction for smart aquaculture technology development in the Republic of Korea through patent analysis and a demand survey of experts and fishermen. The patent analysis was conducted using Wisdomain for patents in the Republic of Korea, the United States of America, Europe, Japan, and China from 2005 to 2016. This study conducted an analytic hierarchy process (AHP) survey of experts in the fields of fishery, marine, and ICT among others. Furthermore, it carried out a demand survey of 85 fishermen in Jeonnam and Jeju. The smart aquaculture technology market has moderately grown in the Republic of Korea until recently, and it is expected to expand further because of the expansion of national investment in the smart aquaculture field. The priority evaluation results for developing smart aquaculture technology show that land-based aquaculture has a higher priority than sea-based aquaculture. Of the fishermen that responded, 84% said that they need to introduce smart aquaculture technology to solve problems in the supply and demand of manpower, labor cost, and maintenance expenses. The direction of development should lie in developing biological and environment-based standard aquaculture models to spread high-tech systems and vitalize the aquaculture industry. This requires continual training of human resources in the smart aquaculture field.

• 생태와환경
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• 제49권1호
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• pp.1-10
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• 2016

산업 및 기술의 발달과 인간 활동의 증가로 인해 자연적인 질소 순환의 균형이 무너지고 다량의 질소가 대기, 토양 및 물 환경 생태계에 과잉으로 존재하게 되었다. 이로 인한 과잉의 반응성 질소화합물이 토양과 물 환경생태계에 영향을 미치고 있는 것을 국내외 문헌과 사례 조사를 통해 확인하고 유역생태계에서 질소화합물로 인한 토양 및 물 환경 생태계의 산성화 영향 감소방안을 제시하였다. 반응성 질소는 대기, 토양 및 물의 여러 매체를 이동하면서 다른 유형으로 전환될 수 있으며 유형 간 상호작용이 일어나기도 한다. 효과적인 질소관리 방안으로 반응성질소 배출원의 다양성 및 유형에 따른 배출량을 규제하는 정책과, 반응성 질소화합물로 인한 토양 및 물 환경생태계의 환경적 피해 (산성화)를 조사 및 평가 (모니터링 및 안전성 지표 적용)하고 복원하는 전략 (예, 화학적 복원 연구 및 개발)이 필요하다.