• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 춘계학술대회
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• pp.161-162
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• 1997

It is very useful to perform the surgery simulation before implanting TAH(Total Artificial Heart} in a patient. The space of chest and the shape of vessels are different from patient to patient. So, It is desirable to customize a TAH design to the anatomy structure of a patient. Several studies are performed to visualize and explain the 3D structure of heart. These studies are performed using 2-dimensional ref or mated images and simple measurement. Anatomy structure of a human heart is not so simple. It is 4dimensional structure ; 3-dimensional plus time, heart beating. 3-dimensional reconstruction schemes of medical images developed for about 10 years are usually categorized into two types of rendering technique ; surface rendering and volume rendering. Volume rendering is preferable in medical image processing field because this technique can be applied without considering the complexity of geometry and change of field of interest. The usable space in the chest of patient can be measured by 3D volume matching of patient trunk and TAH model. This space changes with time. In this research we have developed the 4-dimensional volume match program of patient and TAH model. 3-dimensional rendered set of volumes along time were used to simulate TAH fitting trial. The quantitative measurement from this simulation could be applied to customize TAH design.

• 환경영향평가
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• 제19권2호
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• pp.153-168
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• 2010

The objectives of this study are to analyze flow characteristics for a side weir, which is an inlet structure for flow discharge reduction in the main channel through 3 dimensional numerical analysis and to understand the efficiency of the overflow effect at the side weir. In this study over 40 simulations using FLOW-3D, a computational fluid dynamics program were conducted, and the results were analyzed to find the influence of the flow hydraulics, geometry, channel and weir shapes on the coefficient. It is especially considered the relatively high stage in downstream that may cause flow within channel to be backed up along the channel. Additionally by setting up the scale of simulations much larger than the existing test equipment designed by other researchers, it is intended to analyze more accurate hydraulic behavior along with the realistic hydraulic features such as structures and volumes of flow. The results show that for design with subcritical flow only if the Froude number of upstream is sustained below 0.5 and the length of weir is 33-100% of the width of channel, it is expected to improve the efficiency of the overflow over a side weir.

• 농업과학연구
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• 제10권1호
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• pp.9-21
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• 1983

참나무 임분구조(林分構造)를 그 임분(林分)의 생산성(生産性)과 관련(關聯)시켜 분석(分析)하였다. 해발고(海拔高)에 따른 입지조건(立地條件)에 의(依)해 분류(分類)된 3개(個) 조사구(調査區)가 부여군(扶餘郡) 은산면(恩山面) 나령리(羅嶺里)에 위치(位置)한 참나무 임분(林分)에서 선정(選定)되었다. 임분(林分)의 입지조건(立地條件)은 몇가지 토양이화학적(土壤理化學的) 성질(性質)에 비추어 보통인 것으로 추정(推定)되었다. 굴참나무가 조사(調査)된 임분(林分)의 식생구성(植生構成)에서 우점종(優占種)이었다. 임분(林分)의 소밀도(疎密度)는 plot I의 65.4%에서 plot III의 78.2%까지 변이(變異)를 보였으며 참나무가 차지한 몫들은 plot I의 44.4%에서 plot III의 65.9%까지 이었다. 소밀도(疎密度)와는 달리 참나무류(類)의 축적(蓄積)은 plot I의 $3.937m^3$ (plot 전체(全體)의 73.4%)에서 plot III의 $2.075m^3$ (plot전체(全體)의 84.3%) 까지 이었다. 수형급별(樹型級別)로 측정(測定)된 그 점유비(占有比)는 수관투영면적(樹冠投影面積)과 재적간(材積間)에 상이(相異)했고 또한 plot 별(別)로 다른 pattern을 나타냈다. 개체목(個體木)들의 수관투영면적(樹冠投影面積)과 재적간(材積間)에 plot 별(別)로는 높은 유의성(有意性)이 인정(認定)되었지만 수형급별(樹型級別)로는 인정(認定)되지 않았다. 참나무의 수고(樹高), D.B.H.와 재적(材積)에 있어 누적생장량(累積生長量), 연년생장량(連年生長量), 총평균생장량(總平均生長量)은 plot 별(別), 수형급별(樹型級別)로 상이(相異)한 pattern을 보였다. 수고(樹高)의 연년생장(連年生長) 최대치(最大値)는 보통 D.B.H. 보다는 빨리 10~20년(年)내에 냐타났다. 수고(樹高), D.B.H. 재적(材積)의 총평균(總平均) 생장량(生長量)은 대략 10년(年) 이후(以後)부터 비슷한 수준(水準)을 유지(維持)하면서 불규칙(不規則)하게 변동(變動)했다. 간벌(間伐)에 따른 수관투영면적(樹冠投影面積)과 재적(材積)은 A 종(種)$90m^3$ 정도(程度)로 추정(推定)되었다.

• 한국산림과학회지
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• 제88권3호
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• pp.389-399
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• 1999

본 연구는 개체목의 위치를 포함하는 정밀 임분조사 자료를 이용하여 임분의 3차원 공간구조 분석이 가능한 컴퓨터 프로그램의 개발을 목적으로 수행되었다. 이 프로그램은 임분의 ha당 통계량 계산 등 양적 정보뿐만 아니라 직경, 수고, 재적분포, 그리고 3차원 임분 공간구조와 수관투영도 등의 시각적 정보를 제공하는 기능을 가지고 있다. 또한 컴퓨터 상에서 가상 시업 시뮬레이션을 통해 시업후의 임분구조를 시각적으로 확인할 수 있는 기능을 포함한다. 본 연구에서 개발된 프로그램의 통계분석 부분은 SAS의 분석결과와 비교하였고, 그래픽 정보의 표현 능력은 유사한 3차원 수관도 프로그램인 TreeDraw와 비교하였다. 그 결과 본 연구에서 개발된 프로그램은 자료분석 시간이나 결과의 요약 등 실용성 측면에서 우수한 것으로 나타났다. 본 프로그램을 이용할 경우 해당 임분에 대한 적합한 조림조치와 합리적인 경영에 필요한 다양한 임분 공간정보를 얻을 수 있어 사용자의 의사결정에 도움이 될 것으로 판단된다.

• Carbon letters
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• 제4권3호
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• pp.140-145
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• 2003

Antibacterial behaviors of PAN-based activated carbon fibers (ACFs) containing silver metal were investigated. The effects of surface and pore structures of the ACFs were studied by $N_2$/77 K adsorption and D-R plot as a function of silver loading content. The antibacterial activities were investigated by a dilution test against Staphylococcus aureus (S. aureus; gram positive) and Klebsiella pnemoniae (K. pnumoniae; gram negative). As experimental results, the ACFs showed some decreases in specific surface areas, micropore volumes, and total pore volume with an increase of silver content. However, the antibacterial activities of the ACFs were strongly increased against S. aureus as well as K. pnumoniae, which could be attributed to the presence of antibacterial metal in the ACFs system.

• 한국CDE학회논문집
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• 제12권2호
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• pp.101-108
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• 2007

As 3D solid modeling has been widely used in designing products, solid models of the products are directly used in various applications such as engineering analysis and process planing. However, the fully-detailed solid models may not be necessary in some application. For example, it is often more efficient to use simplified model of part of engineering analysis. Generation of mesh for the complex original model requires a quite amount of time, and the consequence of finite element analysis may not be desirable due to small and detailed geometry in the model. In this paper, a method to simplify solid models of machined part is presented. This method decomposes the delta volume of machined part, and uses the decomposed volumes to simplify the solid model. Since this method directly recognizes the features to be removed from the final model, it is independent of not only design features of specific CAD system, but also designer's design practice of design sequences.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2004년도 정기총회 및 제6최 특별 심포지움
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• pp.8-21
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• 2004

Examples of GPR survey results at a variety of archaeological sites are presented. Several new analyses which include static corrections for the tilt of the GPR antenna are shown for imaging of burial mounds with significant topography. Example archaeological site plans developed from GPR remote sensing of Roman and Japanese sites are given. The first completely automated GPR survey, using only Global Positioning Satellite navigation to create 3D data volumes, is employed for a site in Louisiana to detect lost graves of the Choctaw Indian Tribe.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.616-619
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• 2002

The z-map structure is widely used for NC tool path verification as it is very simple and fast in calculation of Boolean operations. However, if the number of the x-y grid points in a z-map is increased to enhance its accuracy, the computation time for NC verification increases rapidly. To reduce this computation time, we proposed a NC verification method using 3-D graphic acceleration hardwares. In this method, the z-map of the resultant workpiece machined by a NC program is obtained by rendering tool swept volumes along tool pathos and reading the depth buffer of the graphic card. The experimental results show that this hardware-based method is faster than the conventional software-based method.

• 한국작물학회지
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• 제43권3호
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• pp.184-188
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• 1998

Four experiments were conducted to determine growth regulators, their concentrations and treatment time, rooting medium, and plant parts for optimum seedling propagation by stem cuttings in yacon (Polymnia sonchifolia Poepp. & Endl.). NAA was the most effective on rooting, and followed by IBA 2,4-D, and IAA. Dipping the base of cuttings in 50 or 100 ppm solutions of IBA increased rooting ratios. The 100 ppm solution of IBA was 14% higher than the 50 ppm solution for rooting ratios. Rooting medium with equal volumes of clay loam and sand was the most suitable for rooting of cuttings. Cuttings with both terminal bud and the first node or cuttings with both the first and second nodes were higher in rooting ratios than cuttings with only terminal bud or the first or second nodes. Days to rooting was not affected by plant parts.

• 한국초지조사료학회지
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• 제21권2호
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• pp.49-52
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• 2001

conditions for callus induction and plant regeneratin from seeds of lawngrass (Zoysia japonica Steud.) were confirmed in this study. MS (Murashige and Skoog) medium containg 2,4-D 3 or 5mg/l was used for callus induction, and MS medium with different volumes of BA, NAA and kinetin hormones was used to regenerate the plants from induced calli. MS basic medium containing agar with no hormones or kinetin 1.0mg/l and MS basic medium containing gelite and NAA 1.0mg/l were higher for green callus induction. MS medium containing agar and kinetin 1.0mg/l ws highest degree of efficiency for plant regeneration.