• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
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• pp.84-87
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• 1996

This paper presents a energy function to reflect the control effect of speed governor which has a cut-off property which means position and rate limit The proposed energy function satisfies the semi-negativeness of its time derivative and well reflects the parameters of speed governor to the energy function. The transient stability analysis by the direct method for the single machine infinite bus system has been conducted with the use of the proposed energy function, which shows that the results by the direct method well agree with that by the conventional time simulation method. This thesis shows a possibility of more accurate stability analysis by taking into account the cut-off property of speed governor's output.

• 한국인터넷방송통신학회논문지
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• 제14권4호
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• pp.233-241
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• 2014

본 논문은 원 그래프를 2-간선 연결 그래프로 단순화하고, 사이클 속성을 적용하여 최소신장트리를 빠르게 얻는 알고리즘을 제안하였다. Borůvka 알고리즘은 정점 (v) 당 최소 가중치 간선 (v) 을 1개씩 선택하는 1-간선 연결 그래프에 대해 사이클 속성을 적용하여 부분신장트리를 얻는다. 추가적으로 절단속성을 적용하여 부분신장트리를 연결하는 최소 가중치 간선을 선택한다. Kruskal 알고리즘은 그래프의 모든 간선을 대상으로 오름차순으로 절단 속성을 적용한다. 역-삭제 알고리즘은 내림차순으로 사이클 속성을 적용한다. Borůvka, Kruskal과 역-삭제 알고리즘은 모든 간선들을 대상으로 하기 때문에 항상 |e| 회 수행된다. 제안된 알고리즘은 첫 번째로, 정점 당 최소 가중치 간선을 2개씩 선택하는 2-간선 연결 그래프를 얻는다. 두 번째로, 2-간선 연결 그래프에 대해 사이클 속성을 적용하여 |e|=|v|-1 일 때 알고리즘을 종료시켰다. 제안된 방법들을 10개의 실제 그래프들에 적용한 결과 모두 최소신장트리를 얻는데 성공하였다. 또한, Borůvka, Kruskal과 역-삭제 알고리즘에 비해 수행 횟수를 60% 단축시켰다.

• 멤브레인
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• 제22권1호
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• pp.54-61
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• 2012

VOCs의 분리 및 회수를 위해 PEI 고분자를 이용하여 상분리법으로 중공사 지지체 분리막을 제조하였고 PDMS 고분자를 코팅하여 PEI-PDMS 중공사 복합막을 제조하였다. 제조된 기체 분리막의 특성을 알아보기 위하여 산소와 질소를 이용하여 순수 기체 투과도를 측정하였으며, xylene, ethyl benzene, toluene, cyclohexane을 이용하여 stage cut과 feed 농도 변화에 따른 투과성능을 측정하였다. 또한 VOCs에 대한 내용매성을 알아보기 위하여 DMA을 이용하여 용매 함침 시간에 따른 stress-strain 특성을 알아보았다. 산소와 질소의 순수 투과도는 각각 63 GPU와 30 GPU를 나타내었고, stage cut이 증가할수록 permeate VOCs 농도는 감소하는 경향을 나타내었다. Recovery efficiency의 경우 permeate 농도와는 반대로 state cut이 증가할수록 증가하는 경향을 나타내었다. DMA 인장 테스트 결과 stress는 11.93 MPa, strain은 13.52%로 측정되었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.727-735
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• 2010

The collapse of cut slope near national roads in Korea mostly occurs in every summer when typhoon or localized heavy rain comes. Such collapse brings about a loss of many lives and property and recently the damage is on rapidly increasing trend. Therefore, we may reduce the loss of many lives and property in great deals if we can predict and prepare for the collapse of cut slope. However, it is not easy to predict collapse because there are many factors causing collapse in combination and all they have different levels of contribution. Therefore, this study completed prediction formula by using a statistic technique for quantitative analysis on the interaction of those factors so as to predict the stability of slopes. Consequently, it is judged that effective slope management will be possible by selecting dangerous slopes quantitatively among cut slopes near national roads and by preparing for the collapse in advance.

• 산업기술연구
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• 제24권B호
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• pp.107-116
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• 2004

This thesis is results of experimental works on the behavior of the cut-and-cover tunnel. Centrifuge model tests were performed to simulate the behavior of the cut-and-cover tunnels having cross sections of national road and subway tunnels. Model experiments were carried out with changing the cut slope and the slope of filling ground surface. Displacements of tunnel lining resulted from artificially accelerated gravitational force up to 40g of covered material used in model tests, were measured during centrifuge model tests. In model tests, Jumunjin Standard Sand with the relative density of 80 % and the zinc plates were used for the covered material and the flexible tunnel lining, respectively. Basic soil property tests were performed to obtain it's the property of Jumumjin Standard Sand. Shear strength parameters of Jumunjin Standard Sand were obtained by performing the triaxial compression tests. Direct shear tests were also carried out to find the mechanical properties of the interface between the lining and the covered material. Compared results model tests estimation with respect to displacements of the lining.

• 산업기술연구
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• 제23권A호
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• pp.119-130
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• 2003

This thesis is results of experimental works on the behavior of the cut-and-cover tunnel. Centrifuge model tests were performed to simulate the behavior of the cut-and-cover tunnels having cross sections of national road and subway tunnels. Model experiments were carried out with changing the cut slope and the slope of filling ground surface. Displacements of tunnel lining resulted from artificially accelerated gravitational force up to 40g of covered material used in model tests, were measured during centrifuge model tests. In model tests, Jumunjin Standard Sand with the relative density of 80 % and the zinc plates were used for the covered material and the flexible tunnel lining, respectively. Basic soil property tests were performed to obtain it's the property of Jumumjin Standard Sand Shear strength parameters of Jumunjin Standard Sand were obtained by performing the triaxial compression tests. Direct shear tests were also carried out to find the mechanical properties of the interface between the lining and the covered material. Compared results model tests estimation with respect to displacements of the lining.

• 산업경영시스템학회지
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• 제17권32호
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• pp.7-16
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• 1994

In the existing deterministic network, the capacity of each arc has determined property. But actually, it may be a property which cannot be determined. Even though it should be determining, it contains many errors. In treating these kinds of problems, fuzzy theory is suitable. Recently, due to development the study on complicated and indefinited systems which contain fuzziness could be possible. This paper includes that the capacity of each arc and the goal quantity with nonnegative integer have the fuzziness. The object is to search the new mathod of fuzzy maximal flow quantity. If the degree of arc membership function of the minimal cut part is not larger than that of arc membership function of the part except the minimal cut, first calcurate nonfuzzy maximal flow quantity, and then can compute the optimal quantity the 3rd step at one time with Max-Min fuzzy operating in the arc capacity of minimal cut and the goal quantity without a great number of recalculation.

• 한국공작기계학회논문집
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• 제10권6호
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• pp.57-62
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• 2001

Recently, it has increased that the importance of gas pressure weldment of steel bars in large construction bars. But there has hardly been any studies about it. Therefore we need more research. SD40 steel bar (32mm in diameter) which has been practically used at construction sites are tested about tension, bonding, fatigue, a macro structure and micro structure at foil gitudinal section and hardness to fed out the mechanical property and best welding ranges in some cases of mechanical cut and gas cut before gas pressure welded. It is that a gas-pressure welded zone of steel bar where was cleaned of impurities in way of two-upsetted method is more excellent bending and tension property than the regulation of KD D 0244. Also gas cut bars gained hardness from the heat affected zone so. In conclusion, to improve the weldability of steel bars, it is considered best to clean mechanically cut sutra- faces and then weld them by a method of 2 step upset way.

• 복식문화연구
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• 제17권4호
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• pp.575-582
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• 2009

The coffee has been used as drink in the world and it has been using not only food but also dyeing. It can be used for four seasons in our normal living and it can be taken friendly everywhere. The coffee consists of about 8${\sim}$10% phenol(chlorogenic acid) that related to antioxidant and antimicrobial activity. However, its exact components and the dyeing property effects has not been well known yet. Therefore, the purpose of this study was to investigate the dyeing property and ultraviolet-cut ability of silk and nylon fabrics that was dyed variously with coffee extracts. Coffee extracts were done by boiling coffee with distilled water at $100^{\circ}C$ for 2 hours. As mordanting agent, we used $AlK(SO_4)_2$ $12H_2O$, $CuSO_4$ $5H_2O$, $FeCl_2$ $4H_2O$. As the result of the dyeing properties and ultraviolet-cut ability of fabrics dyed with coffee bean extracts, we can find that the optimum dyeing temperature and dyeing time of the silk and nylon fabrics dyed with coffee bean extracts was $90^{\circ}C$, 60 min. and the colorfastness of washing and dry-cleaning was improved by using mordanting agent(4${\sim}$5 grade). Ultraviolet-cut ability was showed more 90% in dyed nylon fabrics.

• 산업기술연구
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• 제24권A호
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• pp.227-238
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• 2004

This paper is results of experimental and nunerical works on the behavior of the cut-and-cover tunnel. Centrifuge model tests were performed to simulate the behavior of the cut-and-cover tunnels having cross sections of national road and subway tunnels. Model experiments were carried out with changing the cut slope and the slope of filling ground surface. Displacements of tunnel lining resulted from artificially accelerated gravitational force up to 40g of covered material used in model tests, were measured during centrifuge model tests. In model tests, Jumunjin Standard Sand with the relative density of 80 % and the zinc plates were used for the covered material and the flexible tunnel lining, respectively. Basic soil property tests were performed to obtain it's the property of Jumumjin Standard Sand. Shear strength parameters of Jumunjin Standard Sand were obtained by performing the triaxial compression tests. Direct shear tests were also carried out to find the mechanical properties of the interface between the lining and the covered material. Numerical analysis with the commercially available program of FLAC were performed to compare with results of centrifuge model experiment In numerical modelling. Mohr-Coulomb elasto-plastic constitutive model was used to simulaye the behavoor of Jumunjin Standard Sand and the interface element between the lining and the covered material was implemented to simulate the interaction between them. Compared results between model tests and numerical estimation with respect to displacement of the lining showed in good agreements.