• 대한수학회논문집
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• 제14권1호
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• pp.19-29
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• 1999

B. Gr nbaum defined the arrangements of simple curves and got many combinatorial properties. In this paper, we studied the existence of (n,r,t,k)-arrangements and the existence of digon-free(n,r,t,k)-arrangements, which is a generalized version of Gr nbaum`s definition.

• 패션비즈니스
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• 제17권5호
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• pp.45-56
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• 2013

This study researches functional arrangements for colors of work clothes - concentrating on the arrangements of lightness - for safety protection of workers at the job sites in the mechanical industry. To conduct such study, blue color (5PB) is selected for the CAD simulations on six arrangements of brightness based on two colors. The brightness ranges are of 5PB color (between 3~7.5) which are measurable by Munsell Conversion, and arrangements on lightness consisting of one arrangement of high lightness-gap, two of medium lightness-gap, and three of low lightness-gap. To analyze the data of color values after applying arrangements of lightness and to evaluate the levels of awareness regarding arrangements, the NCS colorimetric is being applied. Color palettes are based on the NCS notations, and then marked with color triangles. After evaluation, the visibility proves to be high when the arrangements contain high lightness at the top and bottom, and the arrangements with higher lightness-gap show higher effects in safety. Since this study tends to check factors of lightness, the other color factors were limited. Therefore, in order to apply these results at the job sites, integrated applications of such results will be very useful for developing safe working clothes in the future.

• Journal of applied mathematics & informatics
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• 제4권1호
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• pp.279-284
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• 1997

The purpose of this paper is to show that if A is a tame arrangement and a hyperplane H is ageneric then $A^{H}$ is also tame. Since free arrangements are tame we can say tame we can say that almost free arrangements are tame.

• 가정과삶의질연구
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• 제32권3호
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• pp.17-29
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• 2014

This study attempted to explore business and workers'needs for flexible work arrangements focusing on the case of a customer center business. We conducted in-depth interview and focus group interviews with the CEO of the company as well as with workers employed at the company in order to identify their need for flexible work arrangements. The subject of this study is a customer service center business that offers a variety of flexible work arrangements. We found that there is a need for flexible work arrangements in terms of both businesses and workers. These results suggest that flexible work arrangements can be activated when they meet the needs of businesses and workers. Flexible work arrangements can be activated when they meet the businesses'goals in human resource management and workers'goals for achieving work-family balance.

• Wind and Structures
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• 제25권2호
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• pp.101-129
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• 2017

Local transient extreme wind loads caused by group tower-related interference are among the major reasons that lead to wind-induced damage of super-large cooling towers. Four-tower arrangements are the most commonly seen patterns for super-large cooling towers. We considered five typical four-tower arrangements in engineering practice, namely, single row, rectangular, rhombic, L-shaped, and oblique L-shaped. Wind tunnel tests for rigid body were performed to determine the influence of different arrangements on static and dynamic wind loads and extreme interference effect. The most unfavorable working conditions (i.e., the largest overall wind loads) were determined based on the overall aerodynamic coefficient under different four-tower arrangements. Then we calculated the one-, two- and three-dimensional aerodynamic loads under different four-tower arrangements. Statistical analyses were performed on the wind pressure signals in the amplitude and time domains under the most unfavorable working conditions. On this basis, the non-Gaussian distribution characteristics of aerodynamic loads on the surface of the cooling towers under different four-tower arrangements were analyzed. We applied the Sadek-Simiu procedure to the calculation of two- and three-dimensional aerodynamic loads in the cooling towers under the four-tower arrangements, and the extreme wind load distribution patterns under the most unfavorable working conditions in each arrangement were compared. Finally, we proposed a uniform equation for fitting the extreme wind loads under the four-tower arrangements; the accuracy and reliability of the equation were verified. Our research findings will contribute to the optimization of the four-tower arrangements and the determination of extreme wind loads of super-large cooling towers.

• 대한수학회보
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• 제54권2호
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• pp.375-382
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• 2017

We exhibit a one-to-one correspondence between 3-colored graphs and subarrangements of certain hyperplane arrangements denoted ${\mathcal{J}}_n$, $n{\in}{\mathbb{N}}$. We define the notion of centrality of 3-colored graphs, which corresponds to the centrality of hyperplane arrangements. Via the correspondence, the characteristic polynomial ${\chi}{\mathcal{J}}_n$ of ${\mathcal{J}}_n$ can be expressed in terms of the number of central 3-colored graphs, and we compute ${\chi}{\mathcal{J}}_n$ for n = 2, 3.

• 대한수학회지
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• 제54권5호
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• pp.1595-1604
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• 2017

We give a complete formula for the characteristic polynomial of hyperplane arrangements ${\mathcal{J}}_n$ consisting of the hyperplanes $x_i+x_j=1$, $x_k=0$, $x_l=1$, $1{\leq}i$, j, k, $l{\leq}n$. The formula is obtained by associating hyperplane arrangements with graphs, and then enumerating central graphs via generating functions for the number of bipartite graphs of given order, size and number of connected components.

• 대한기계학회논문집B
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• 제25권11호
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• pp.1640-1649
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• 2001

The present study investigates the effects of various rib arrangements on heat/mass transfer in the cooling passage of gas turbine blades. A complex flow structure occurs in the cooling passage with rib turbulators which promote heat transfer on the wall. It is important to increase not only the heat transfer rates but also the uniformity of heat transfer in the cooling passage. A numerical computation is performed using a commercial code to calculate the flow structures and experiments are conducted to measure heat/mass transfer coefficients using a naphthalene sublimation technique. A square channel (50 mm $\times$ 50 mm) with rectangular ribs (4 mm $\times$ 5 mm) is used fur the stationary duct test. The experiments focus on the effects of rib arrangements and gap positions in the discrete ribs on the heat/mass transfer on the duct wall. The rib angle of attack is 60°and the rib-to-rib pitch is 32 mm, that is 8 times of the rib height. With the inclined rib angle of attack (60°), the parallel rib arrangements make a pair of counter rotating secondary flows in the cross section, but the cross rib arrangements make a single large secondary flow including a small secondary vortex. These secondary flow patterns affect significantly the heat/mass transfer on the ribbed wall. The heat/mass transfer in the parallel arrangements is 1.5 ∼2 times higher than that in the cross arrangements. However, the shifted rib arrangements change little the heat/mass transfer from the inline rib arrangements. The gap position in the discrete rib affects significantly the heat/mass transfer because a strong flow acceleration occurs locally through the gap.

• 농업생명과학연구
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• 제43권6호
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• pp.53-57
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• 2009

동양꽃꽂이는 고대에 신에게 헌화한 공화양식으로 좌우대칭의 삼존형식의 엄격한 삼각형의 조형미를 갖추고 있었으며 침봉을 사용하여 꽃을 고정하므로 쉽게 꽂을 수 있었다. 서양꽃꽂이는 이집트시대에 꽃을 연속반복으로 쌓아 올려 원추형의 형태를 이루어 현재 vertical form의 근원으로 보고 있다. 그리이스 시대에는 부드러운 S라인 형식을 주로 사용하였고, 로마시대에는 꽃들의 중심을 풍성하고 화려하게, 갈수록 낮고 가늘며 긴 수평형으로 연결하였다. 페르시아 시대에는 동양의 삼존형식과 비슷한 triangular 조형을 나타내고 있다. 그리고 르네상스 시대에 꽃꽂이도 고전의 바탕위에 기본형이 창조되었으며, 19세기말 동양미술의 온화한 색과 단순미, 사실적 묘사 등에 영향을 받아 20세기 미국을 중심으로 양적 mass에서 공간미학까지 꽃꽂이의 영역이 광범위하게 표현되는 art nouveau 시대로 이어졌다. 서양꽃꽂이는 조형성에 기초를 두는 것은 동양꽃꽂이와 같으나 자연성이 거의 무시되고 실용성에 근거를 삼는 것이 특징이다.

• 가정과삶의질연구
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• 제30권2호
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• pp.173-187
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• 2012

This qualitative case study focused on the activation plan of flexible work arrangements. We selected eight workers from a foreign affiliated firm that has various flexible work arrangements for in-depth interview and focus group interview. The workers were categorized into two groups; those who have experiences with flexible working and those who have needs for flexible working. We analyzed their condition of work-family life and experiences with flexible working. Through the focus group interview, we can find out the needs and suggestions about activation plans of flexible work arrangements.