• 한국CDE학회논문집
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• 제13권6호
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• pp.450-458
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• 2008

Recently, Cartesian grid approach has been popular to generate grid meshes for complex geometries in CFD (Computational Fluid Dynamics) because it is based on the non-body-fitted technique. This paper presents a method of an octree generation and boundary cell clipping using section curves for fast octree generation and elimination of redundant intersections between boundary cells and triangles from 3D triangular mesh. The proposed octree generation method uses 2D Scan-Converting line algorithm, and the clipping is done by parameterization of vertices from section curves. Experimental results provide octree generation time as well as Cut-cell clipping time of several models. The result shows that the proposed octree generation is fast and has linear relationship between grid generation time and the number of cut-cells.

• Journal of Korean Neurosurgical Society
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• 제57권6호
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• pp.455-459
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• 2015

Objective : A cost comparison of the surgical clipping and endovascular coiling of unruptured intracranial aneurysms (UIAs), and the identification of the principal cost determinants of these treatments. Methods : This study conducted a retrospective review of data from a series of patients who underwent surgical clipping or endovascular coiling of UIAs between January 2011 and May 2014. The medical records, radiological data, and hospital cost data were all examined. Results : When comparing the total hospital costs for surgical clipping of a single UIA (n=188) and endovascular coiling of a single UIA (n=188), surgical treatment [$mean{\pm}$standard deviation (SD) : \$8,280,000{\pm}1,490,000$] resulted in significantly lower total hospital costs than endovascular treatment ($mean{\pm}SD$ : \$11,700,000{\pm}3,050,000$, p<0.001). In a multi regression analysis, the factors significantly associated with the total hospital costs for endovascular treatment were the aneurysm diameter (p<0.001) and patient age (p=0.014). For the endovascular group, a Pearson correlation analysis revealed a strong positive correlation (r=0.77) between the aneurysm diameter and the total hospital costs, while a simple linear regression provided the equation, y (\)=6,658,630+855,250x (mm), where y represents the total hospital costs and x is the aneurysm diameter. Conclusion : In South Korea, the total hospital costs for the surgical clipping of UIAs were found to be lower than those for endovascular coiling when the surgical results were favorable without significant complications. Plus, a strong positive correlation was noted between an increase in the aneurysm diameter and a dramatic increase in the costs of endovascular coiling.

• The Korean Journal of Physiology and Pharmacology
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• 제3권3호
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• pp.351-356
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• 1999

The present study was aimed at investigating whether the calcium current in the vascular smooth muscle (VSM) cells is altered in renal hypertension. Two-kidney, one clip (2K1C) and deoxycorticosterone acetate (DOCA)-salt hypertension were made in Sprague-Dawley rats. Rats without clipping the renal artery or implanting DOCA were used as control for 2K1C and DOCA-salt hypertension, respectively. Four weeks after clipping, systolic blood pressure was significantly higher in 2K1C rats than in control $(192{\pm}24\;and\;119{\pm}4$ mmHg, respectively, n=16 each). DOCA-salt rats also showed a higher blood pressure $(180{\pm}15$ mmHg, n=18) compared with control $(121{\pm}6$ mmHg, n=14). VSM cells were enzymatically and mechanically isolated from basilar arteries. Single relaxed VSM cells measured $5{\sim}10\;{\mu}m$ in width and $70{\sim}150\;{\mu}m$ in length were obtained. VSM cells could not be differentiated in size and shape between hypertensive and normotensive rats under light microscopy. High-threshold (L-type) calcium currents were recorded using whole-cell patch clamp technique. The amplitude of the current recorded from VSM cells was larger in 2K1C hypertension than in control. Neither the voltage-dependence of the calcium current nor the cell capacitance was significantly affected by 2K1C hypertension. By contrast, the amplitude of the calcium current was not altered in DOCA-salt hypertension. These results suggest that high-threshold calcium current of the VSM cells is altered in 2K1C hypertension, and that calcium channel may not be involved in calcium recruitment of VSM in DOCA-salt hypertension.

• 한국공간정보시스템학회 논문지
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• 제6권2호
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• pp.23-37
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• 2004

최근 GPS기능을 탑재한 휴대폰 PDA등의 모바일 장치를 사용하여 위치 기반 서비스를 이용하는 사용자가 급증하고 있다. 이에 위치 정보를 지닌 공간 데이타를 저장하고 관리하는 대용량의 공간 데이타베이스는 사용자의 다양한 질의 조건과 빠른 검색을 가능하게 하기 위한 색인이 필요하며 대표적인 색인 기법으로는 R-tree가 널리 사용되고 있다. 기존의 R-tree를 이용한 검색은 질의 영역과 관계없는 공간 데이타까지 검색하여 불필요한 입출력을 유발하기 때문에 응답시간이 늦어진다. 본 논문에서는 공간 데이타가 위치 기반 질의를 지원하기 위해 자신이 속한 노드의 전체(Union) MBR 영역에 따라 동적으로 셀 레벨 값을 구성하는 CLR-트리(Cell Leveling R-tree)를 제안한다. 또한, CLR-트리에서의 새로운 공간 데이타의 삽입, 분할, 삭제, 검색 알고리즘을 제안한다. 제안된 CLR-트리에서는 위치 기반 질의 시 사용자 질의 영역의 셀 레벨 값과 공간 데이타의 셀 레벨 값을 비교하여, 겹치지 않는 셀에 대해서는 검색 대상으로부터 제거하고 연관된 셀만을 검색하기 때문에 빠른 응답시간을 제공한다. 디스크 입출력 실험에서 CLR-트리가 기존 R-tree보다 디스크 접근 수를 $5{\sim}20%$ 감소시켜 사용자의 위치 기반 질의에 대해 빠르게 처리함을 알 수 있었다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제3권2호
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• pp.87-90
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• 1998

Hemolymph is oxidized and darkens visibly during the collection from silkworm due to the activity of tyrosinase in it. Toxic quinones are produced by the oxidation and consequently inhibit the cell growth. Heat treatment can be used to prevent the oxidation ; however, the oxidation may occur during the collection of hemolymph before it is heat-treated. It makes the hemolymph collection difficult especially on a large-scale preparation. Hemolymphs collected from 257 different strains of silkworms were examined to select the slowly oxidized hemolymphs. Hemolymphs collected from mutant strains such as Lemone, TBO, Cre, Y4, and wEb showed relatively slow color changes. Oxidation rates of the hemolymphs were measured by the absorbance change using a spectrophotometer. The hemolymph of wEb showed the slowest oxidation. The absorbance of this mutant hemolymph reached the saturation value at 20$^{\circ}C$ in 450 min, whereas the total oxidation time of the wild-type (Baekokjam) hemolymph at the same temperature was 120 min. We tested if this mutant hemolymph is useful as a medium supplement for insect cell culture. Cell growth rate and final cell concentration in the medium supplemented with the wEb hemolymph were almost same as those in the medium supplemented with the wild-type hemolymph. Hemolymph is collected on a small scale by clipping the abdominal leg; however, this method is not appropriate fro large scale preparation. Centrifugation after chopping the silkworm hemolymph by a blending mixer is a more appropriate procedure for large scale collection. Slowly oxidized wEb hemolymph resulted in higher cell concentration than the wild-type hemolymph when hemolymph was collected by the large scale preparation method.

• Journal of Korean Neurosurgical Society
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• 제41권3호
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• pp.153-156
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• 2007

Objective : Cerebral vasospasm is a devastating medical complication of aneurysmal subarachnoid hemorrhage [SAH]. Therefore, prompt detection of vasospasms in aneurysmal SAH is important to the clinical outcome of the patient. For better prediction and effective management of vasospasms, identifying risk factors is essential. This study is aimed at evaluating the relationship between clinical hematologic values, especially white blood cell count, and cerebral vasospasms. Methods : A retrospective review was conducted on 249 patients with aneurysmal SAH who underwent surgical clipping [230 cases] or endovascular intervention [19 cases] between 2003 and 2005. The underlying clinical conditions assessed were leukocytosis, fever, hypertension, diabetes, smoking, Hunt and Hess grade, Fisher grade, aneurysm location, and direct clipping versus endovascular intervention. Results : Two hundred forty-nine patients were treated for aneurysmal SAH during this period. We selected 158 patients in Hunt and Hess grade I - III. Cases of infectious conditions, rebleeding and other surgical/clinical complications were excluded. Vasospasms occurred $7.0{\pm}3.1$ days after the onset of SAH. There were several independent predictors of vasospasm : Fisher grade III [p=0.002], fever within two weeks on admission [p<0.001], and a serum leukocyte count >$10.8{\times}10^3/mm^3$ on admission [p=0.018]. Conclusion : This study results indicate that leukocytosis and fever increase the risk of vasospasms. However, other known risk factors, such as hypertension and smoking, were not correlated with respect to predicting of cerebral vasospasm. Monitoring the serum leukocyte count may be a helpful and useful marker of vasospasms after aneurysmal SAH.

• 대한의생명과학회지
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• 제8권3호
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• pp.155-159
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• 2002

To evaluate the physiological significance of xanthine oxidase (XO) in rat skin, the activity of XO (type O) in skin was compared with that of small intestine or liver. Concomitantly, XO activities in some partial portions (scalp, leg, dorsal and ventral part) of skin were determined and then compared with each partial portion. XO activity of skin was lower than that of small intestine and rather higher than that of liver. Furthermore, the activity of XO in skin, after clipping of hairs and then in 5 days, was more increased than that of rat which was clipped before having been sacrificed. As for activities of free radical scavenging system (GPx, GST, SOD), skin is lower than liver and small intestine. Although it is hewn that the oxygen free radical generated by XO system lead to injurious effect on the cell, the XO activity of ventral part which is to be less exposed to xenobiotics and biological agents was the lowest among those of ventral, dorsal, leg and scalp parts in skin. In conclusion, it may be hypothesized that XO system in skin act on defence mechanism.

• 한국작물학회지
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• 제50권2호
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• pp.79-83
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• 2005

Rice and weed interference in the paddy field caused by resource competition and allelopathy. Evaluation method of active weed suppressive behavior of rice to weed was developed by eliminating light competition at soil condition. Twenty eight days old rice seedlings (6-7 leaf stage) which was grown at saturated, no drainage pot were clipped above $3\~4cm$ from the soil surface. Weeds seeded around clipped rice stem, named ratoon seeding screening method, showed varietal suppressive difference to Echinochloa crus-galli, Echinochloa crusgalli var. praticola and Monochoria vaginalis. Potential allelopathic rice varieties, Sathi, AC1423 and PI312777 showed better suppressive activity to weed seedling growth than Nonganbyeo and Keumobyeo. Weed suppression of one plant of rice cultivars could be evaluated by the cell size of $2.5\times2.5cm$ at rice clipping of seedling 29 days after rice seeding.

• 한국콘텐츠학회논문지
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• 제6권12호
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• pp.105-112
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• 2006

본 연구에서는 일반적으로 잘 알려진 기저 세포암 검출을 위한 간단한 전처리 방법을 제안하였다. 전처리 과정은 half Hanning 윈도우와 함께 데이터를 클리핑하고 PCA(principal components analysis)를 이용하여 차원을 감소하였다. Half Hanning 윈도우는 $1650cm^{-1}$ 피크 부근의 크기를 낮춤으로써 음성 오류율을 줄여 분류 성능을 향상시켰다. 이 실험에서 사용한 MAP(maximum a posteriori), KNN (k-nearest neighbor), PNN(probabilistic neural network), MLP(multilayer perceptron), SVM(support vector machine)와 MSE(minimum squared error)의 분류결과는 제안한 방법이 효과적임을 입증하고 있다. KNN 분류방법은 216개 라만 스펙트럼에 대한 분류실험에서 민감도가 약 97.3%로 제안한 윈도우를 적용한 이 실험에서 기저 세포암 검출 성능이 가장 많이 개선되었다.

• 아시안잔디학회지
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• 제20권1호
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• pp.25-31
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• 2006

'Meyer' zoysiagrass(Zoysia iaponica Steud.)는 일반적으로 미국 중부지역에서 골프장 페어 웨이 또는 티에 일반적으로 많이 쓰이는 잔디로 적은 시비와 관수와 함께 좋은 플래이를 제공한다. 하지만 그늘 지역에서의 생육이 저하되어 품질을 떨어뜨린다. 감소되어진 광량은 잔디 잎의 웃자람을 일으키며 밀도가 저하되고 약한 잔디 생육과 함께 답압이나 디보트에 따른 재생을 저하시킨다. 이 실험의 목적은 TE의 처리가 그늘 지역에서의 잔디의 웃자람을 억제하고 품질을 향상 시키는가를 알아보기 위함에 있다. 이 실험에서 두 가지 처리는 차광 조건(0%, 79%, 92% 차광막) 과 TE [0, 48(0.5x), $96g{\cdot}ha^{-1}\;a.i(1x)$]로 적용하였다. 무 차광 처리 시, 0.5x-비율로 TE처리에서 4 주후 무 처리구에 비해 18%의 잔디 예초물의 감소를 보였고 1x-비율의 TE 처리는 $30{\sim}38%$의 예초물 감소를 보였다. 매달 1x-비율의 TE 처리 시 무 차광 처리와 79% 차광에서 zosiagrass의 밀도를 증가 시켰다. 무 처리에 비해 두 TE 비율의 처리가 잔디의 웃자람을 감소시켰으며 1x-비율로 TE 처리 시 79% 차광에서 잔디 품질이 저하되는 것이 지연되었다. 이 실험에서 그늘진 지역에서의 TE 처리가 zoysiagrass 의 웃자람을 줄이고 잔디 품질을 향상 시킨다는 것을 알 수 있었다.