• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제26권2호
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• pp.108-120
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• 2022

We considered qualitative behaviour of the generalization of Einstein's model of Brownian motion when the key parameter of the time interval of free jump degenerates. Fluids will be characterised by number of particles per unit volume (density of fluid) at point of observation. Degeneration of the phenomenon manifests in two scenarios: a) flow of the fluid, which is highly dispersing like a non-dense gas and b) flow of fluid far away from the source of flow, when the velocity of the flow is incomparably smaller than the gradient of the density. First, we will show that both types of flows can be modeled using the Einstein paradigm. We will investigate the question: What features will particle flow exhibit if the time interval of the free jump is inverse proportional to the density and its gradient ? We will show that in this scenario, the flow exhibits localization property, namely: if at some moment of time t₀ in the region, the gradient of the density or density itself is equal to zero, then for some T during time interval [t₀, t₀ + T] there is no flow in the region. This directly links to Barenblatt's finite speed of propagation property for the degenerate equation. The method of the proof is very different from Barenblatt's method and based on the application of Ladyzhenskaya - De Giorgi iterative scheme and Vespri - Tedeev technique. From PDE point of view it assumed that solution exists in appropriate Sobolev type of space.

• 대한수학회보
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• 제61권3호
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• pp.825-835
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• 2024

We describe the local transition probability of a singular diagonal action on the standard non-uniform quotient of PGL₃ associated to the type 1 geodesic flow. As a consequence, we deduce the property of strongly positive recurrence.

• 수산해양교육연구
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• 제26권4호
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• pp.902-914
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• 2014

The purpose of this study is to provide useful information by analysis on mathematic classes for improve interactions between teacher and student using the Flanders Category System. For this, mathematic classes were observed by videotapes and recorded, 10 recorded videotapes were selected for analysis the property of linguistic interaction. The collected videotapes and records materials were transcribed by Advanced Flanders(AF) analysis program version 3.54. The detail investigated topics for studying are as follows. 1) What is the property of the Flanders 10 code analysis results? 2) What is the property of main and subsidiary linguistic flow of interaction? 3) What is the property of the Flanders index analysis results? The results of this study are as follow: 1) In Flanders 10 code analysis results, teacher's non-directive speaking is 12.76%, teacher's Indicative speaking is 50.28%, student's reactive speaking is 4.07%, student's voluntary speaking is 9.66%. 2) Among the 10 classes, 5 classes' main flow is 'ask convergent question ${\rightarrow}$ student's reactive speaking ${\rightarrow}$ lecture ${\rightarrow}$ ask convergent question', 2 classes' main flow is 'lecture ${\rightarrow}$ ask convergent question ${\rightarrow}$ student's reactive speaking ${\rightarrow}$ lecture', 3 classes' main and subsidiary flow is 'lecture ${\rightarrow}$ ask convergent question ${\rightarrow}$ lecture ${\rightarrow}$ work'. 3) In indices results, revised I/d ratio, student's speaking ratio, student question, wide answer ratio are higher than analysis standard and indirect ratio, teacher's question ratio are lower than analysis standard.

• Elastomers and Composites
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• 제9권1호
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• pp.5-13
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• 1974

The characteristics of IR and IR blended elastomers, for footwear by means of blending with NR and SBR, have been studied. The results obtained were as follows: 1. The mastication of IR was almost not required, where as NR and SBR are necessary. Therefore mixing time was much reduced because of speedy filler feeding. 2. Disadvantage of low Mooney viscosity was covered by blending with NR and SBR, and by loading filler. Superior flow property in comparison to other polymers was worthy and valuable in providing formulas for mould flow, 3. The elongation property of green stocks and vulcanizates was shown smooth surface for extruded and calendered stocks, and facilitated fabrication processes. 4. Because of slow vulcanization, IR is required to control vulcanization time by adding proper accelerators. This property, in turn, made possible to improve the storing stability of green stocks by controlling scorch time.

• 대한의용생체공학회:의공학회지
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• 제42권4호
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• pp.143-149
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• 2021

In order to predict and prevent the disease of the abdominal aorta, which is the largest artery in the human body and the most common aneurysm, the normal arterial blood flow operation should be considered. To this end, we are trying to solve problems that may arise in the future by executing FSI based on the data obtained from 4D flow MRI. However, to match the similarity between the 4D flow MRI flow and the FSI flow, correlation was used in previous papers, but the correlation did not show the degree of agreement. Therefore, in this paper, we analyzed the correlation between the 4D flow MRI flow velocity of the human abdominal aorta and the two-way FSI flow velocity in which the three physical properties used for the aortic FSI were added to the CT abdominal aorta 3D model and the interclass correlation coefficient. As a result, the physical property M2 showed the highest similarity in correlation and intraclass correlation coefficient, and this property is intended to be helpful in the future study of the abdominal aortic two-way FSI flow rate.

• 대한조선학회논문집
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• 제43권2호
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• pp.268-274
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• 2006

Analysis has been made of the anti-corrosive property of organic coating under the shear stress of the flow by means of AC impedance method. Marine anti-corrosive painted panels were placed in the water channel with varying flow rate, thereby experiencing varying flow shear stress on the surfaces. The velocities of the salt water were ranged from 1.48 to 5.2 m/s and the coating thickness of from $70{\mu}m\;to\;140{\mu}m$. For all coating thicknesses investigated, the poorer anti-corrosive property and the lower adhesion strength have been found for the higher shear stress. It has been found that the shear stress accelerates the aging of organic marine coatings.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.521-524
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• 2008

2002년 태풍 ‘루사’로 인하여 재산피해가 약 5조 4,000억원 발생하였고, 도로 및 철도 등 주요시설물 피해는 12,377개소에서 약 2조 8,600억원으로 약 전체 피해액의 53%에 달했다. 2003년 태풍 ‘매미’에 의한 재산피해는 약 4조 2000억원으로 나타났다. 최근 2006년 7월 태풍 ‘에위니아’로 인한 재산 피해는 약 1조 4000억원으로, 도로 127개소, 하천 65개소 등의 주요 시설물이 유실 또는 침수 피해를 입었다. 따라서, 이상기후에 의한 매년 반 복되는 집중호우로 도로의 피해를 최소화하기 위하여, 본 논문은 도로의 피해 원인인 토석류를 고려한 도로 배수시설의 규격 결정 방안을 제시하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.596-599
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• 2004

The purpose of this study is to investigate properties of porous concrete according to rheological properties of binder and compaction factor. The results of this study, the rheological property of binder is stabilized when a mixing time is over 240 seconds in case of target flow values are $175\%\;and\;200\%$. The void ratio of specimen has a very near value by target void ratio on the whole according as the rheological properties of binder and compaction energy are changed when target flow value is $200\%$, compaction energy is $75kN{\cdot}m/m^2$. The specimen has the excellent compressive strength when compaction energy and target flow value are $100kN{\cdot}m/m^2$ and $200\%$ respectively.

• 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.

• 해양환경안전학회지
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• 제12권1호
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• pp.9-14
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• 2006

유기도막의 방식성능은 도막의 수지성분과 안료의 화학적 특성에 의존한다 전자는 부식인자의 침투를 차단 및 지연시키는 역할을 하며, 후자는 침투된 부식인자들에 의해 일어나는 부식반응을 억제하는 기능을 갖고 있다. 또한 도막 자체의 영향 외에, 외부 환경에 의해서 다르게 나타난다. 본 연구에서는 교류 임피던스 법을 이용하여 유속과 그에 따른 유동 전단응력에 의한 도막의 열화거동을 조사하였다. 실험기 사용된 도막의 두께는 $70{\mu}m$에서 $140{\mu}m$까지 변화시켰다. 두꺼운 도막($140{\mu}m$) 에서는 유속이 증가함에 따라 물 흡수량의 감소와 높은 임피던스 특성을 나타내었다. 그러나 얇은 도막($90{\mu}m$) 에서는 유속이 증가함에 따라 도막의 파괴가 진행되고 있음을 확인할 수 있었다. 도막에 가해지는 전단응력이 증가할수록, 즉 선박의 운항속도가 증대될수록 도막의 열화에 의하여 방식성능이 떨어짐을 확인할 수 있었다.