• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.534-537
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• 2004

In this paper, a dynamic behavior of spring supported cantilever beam with a crack and a moving mass is presented. Based on the Euler-Bernoulli beam theory, the equation of motion can be constructed by using the Lagrange's eauation. The crack section is represented by a local flexibility matrix connecting two undamaged beam segments i.e. the crack is modelled as a rotational spring. This flexibility matrix defines the relationship between the displacements and forces across the crack section and is derived by applying fundamental fracture mechanics theory. And the crack is assumed to be in the first mode of fracture. As the depth of the crack is increased the tip displacement of the cantilever beam is increased.

• Genomics & Informatics
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• 제17권2호
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• pp.18.1-18.10
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• 2019

Prediction of the relations among drug and other molecular or social entities is the main knowledge discovery pattern for the purpose of drug-related knowledge discovery. Computational approaches have combined the information from different sources and levels for drug-related knowledge discovery, which provides a sophisticated comprehension of the relationship among drugs, targets, diseases, and targeted genes, at the molecular level, or relationships among drugs, usage, side effect, safety, and user preference, at a social level. In this research, previous work from the BioNLP community and matrix or matrix decomposition was reviewed, compared, and concluded, and eventually, the BioNLP open-shared task was introduced as a promising case study representing this area.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1744-1746
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• 2004

This paper focuses on the problem of asymptotic stabilization for time-delay systems. To this end, a memoryless state feedback controller is proposed. Then, based on the Lyapunov method, a delay-dependent stabilization criterion is devised by taking the relationship between the terms in the Leibniz-Newton formula into account. Certain free weighting matrices are used to express this relationship and linear matrix inequalities (LMIs)-based algorithm to design the controller stabilizing the system.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제5권1호
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• pp.1-10
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• 2001

We investigate the relationship between the 0-tree and other trees in linear nongroup cellular automata. And we show that given a 0-basic path of 0-tree and a nonzero attractor ${\alpha}$ of a multiple attractor linear cellulara automata with two predecessor we construct an ${\alpha}$-tree of that multiple attractor linear cellular automata.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1998년도 추계학술대회 논문집
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• pp.261-266
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• 1998

In this study, crush characteristics of thin-walled rectangular tube is investigated. The stiffness of the element is obtained from analytical moment-rotation relationship and approximated load-deflection relationship of thin-walled rectangular tube. A computer program is developed for the large deformation analysis of frame. An incremental displacement method is used in the program and at each incremental stage, the stiffness matrix of the total structure is checked with the state each element for bending and compression.

• 한국산학기술학회논문지
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• 제19권6호
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• pp.677-682
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• 2018

관계분석형 R&D 포트폴리오 방법은 중점기술의 선정기준이 독립적일 경우 각 선정기준의 고유한 목적과 특성을 반영하여 중점기술을 선정하는 방법이다. 본 연구는 중점기술을 도출하기 위한 방법으로 관계분석형 R&D 포트폴리오 방법을 제시하고 선정기준과 분석지표간의 상관관계 분석하는 1단계, 각 선정기준에 최적으로 부합하는 포트폴리오 매트릭스를 구성하는 2단계, 중점기술을 도출하는 3단계로 나누어 방법론을 적용하는 과정을 서술하였다. 본 연구에서는 중점기술을 선정하기 위한 4대 선정기준과 기술수준, 경제성, 기술성을 파악하기 위한 분석지표간의 상관관계를 HoQ를 응용한 표로 작성하였다. 상관관계표를 바탕으로 각 선정기준을 최적으로 만족하기 위해 고려해야 할 분석지표를 도출하였으며, 도출된 분석지표와 선정기술을 두 축으로 포트폴리오 매트릭스를 구성하였다. 4대 기준을 모두 충족하는 충족형 포트폴리오 P0와 4대 선정기준의 고유한 특성을 반영하여 각 선정기준을 효과적으로 충족하는 포트폴리오 P1~P4를 구성하여 중점기술을 도출하였다. 선정된 중점기술은 명세기반의 키워드 분석 등의 과정을 거쳐 미래 안보환경에 대응하기 위한 중점분야 선정에 활용될 수 있다.

• 물과 미래
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• 제18권3호
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• pp.253-264
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• 1985

근본적으로 저수지의 Storage-Yield 관계를 해석하는 데는 두가지 관점이 있다. 가장 보편적인 관점은 필요한 수요량을 공급하기 위하여 저수지의 필요저수용량을 결정하는 것이다. 이런 형태의 문제는 저수지의 계획이나 초기 설계단계에서 보통 생긴다. 두 번째 관점은 주어진 저수용량에 대한 방류량의 결정이며, 이것은 최종 설계나 더 상세한 분석을 위한 현존 저수지의 재평가에서 자주 생긴다. 본 연구의 목적은 저수지의 설계나 운영을 위한 Storage-Yield 관계를 산정하는 현재의 방법론을 개선하는 것이다. 저수지의 Storage-Yield 관계를 해석하느 s가장 적합한 기법을 찾기 위하여 잔차누가곡선기법(Residual mass curve technique), 개선된 저류량기법(Low flow technique)과 TPM 기법(Transition probability matrix technique)이 검토되었다. 저수지의 Storage-Yield 관계를 해석하는데 있어서 홍천댐 건설예정지점의 1917∼1940년 월유입량 자료와 Thomas-Fiering 모델에 의해 모의 발생된 자료를 가지고 위의 세가지 기법을 상세히 검토하였다. 저수지의 Storage-Yield 관계를 폭넓게 검토한 결과, 잔차누가곡선기법과 저류량기법은 예비 설계에 타당하며, TPM 기법은 월별 혹은 계절별 수요변동을 고려할 수 있기 때문에 최종 설계에 타당한 기법임을 알 수 있다.

• 대한화장품학회지
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• 제22권2호
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• pp.182-192
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• 1996

In this study, the relationship between wax matrix in lipstick and sweating was investigated by observing the change of size and shape of wax matrix with sweating by Scanning Electron Microscopy (SEM). For observation by SEM, a lipstick sample was frozen in liquid nitrogen, then the oil in the lipstick was extracted out in cold isopropanol($-70^{\circ}C$) for 1-3days. After isopropanol was evaporated, the sample was sputtered with gold, and examined by SEM. When examined the sweated sample by SEM, the change of wax matrix underneath the surface from fine, uniform structure to coarse, nonuniform structure was observed, which was resulted from the caking of surrounding wax matrix. That is, the oil underneath the surface was migrated to the surface of lipstick with sweating, consequently the wax matrix at that region was rearranged into the coarse matrix. In case of flamed lipstick, sweating was delayed and the wax matrix was much coarser than that of unflamed one. Its larger wax matrix at surface region was good for including oil. The effect of molding temperature on sweating was also studied. As the molding temperature was increased, sweating was greatly reduced and the size of wax matrix was increased. It was also found that sweating was influenced with the compatinility of wax and oil. A formula consisting of wax and oil which have good compatibility has a tendency of reduced sweating and increased size of wax matrix. When pigment was added to wax and oil. It was also found that sweating was influenced with the passage of time by observing a thick membrane of wax on surface of lipstick after a month from molding. In case of some lipsticks, the size of wax matrix was altered to bigger or smaller. In conclusion, the structure of wax matrix at the surface region of lipstick was changed with the process of foaming, molding temperature, compatibility of wax and oil, addition of pigment, and the passage of time. In most cases, as the size of wax matrix was increased, sweating was reduced and delayed.

• 폴리머
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• 제24권4호
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• pp.459-468
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• 2000

유리 또는 아라미드 섬유를 보강재로 사용한 섬유강화 복합재료의 기계적 물성을 증진시키기 위하여 복합재료 적층판을 서로 다른 매트릭스 수지와 섬유를 선정하여 이들의 인장, 굴곡 특성을 조사하였다. 불포화 폴리에스테르와 개질된 표면의 아라미드 섬유 복합재료의 경우, 굴곡 물성의 최대값은 실란 농도가 0.5 wt%일 때 관찰되었다. 불포화 폴리에스테르 수지와 유리섬유 복합재료의 인장 물성은 vinylester계가 가장 높게 나타났으며, 굴곡물성은 isophthalic계가 가장 높은 물성을 나타내었다. 유리섬유와 불포화 폴리에스테르 수지 복합재료의 기계적 물성을 증진시키기 위해 겹침 적층판과 기계적 물성과의 상관 관계에 대해서도 연구가 병행되었다.

• 약학회지
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• 제48권2호
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• pp.165-170
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• 2004

The production of matrix metalloproteinases (MMPs) by the UV irradiated skin fibroblast and the degradation of extracellular matrix (ECM) by these enzymes is known as one of the main reasons of photoaging. In this paper, to investigate the relationship between aging and Selaginella tamariscina extract (STE), we investigated the effects of antioxidant and expression of UVA-induced MMP-1 in human dermal fibroblasts. STE was found to show scavenging activities of radicals and reactive oxygen species (ROS) with the $IC_{50}$/ values of 65.1 $\mu\textrm{g}$/$m\ell$ against 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical and 40.9 $\mu\textrm{g}$/$m\ell$ against superoxide radicals in the xanthine/xanthine oxidase system, respectively. UVA induced MMP expression was reduced 75.5% by treatment with STE, and MMP-1 mRNA expression was reduced in a dose-dependent manner. Therefore STE was able to significantly inhibition of MMP expression in protein and mRNA level. All these results suggested that STE may act as an anti-aging agent by antioxidation and reducing UVA-induced MMP-1 production.