• 한국연초학회지
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• 제26권1호
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• pp.27-34
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• 2004

This study was carried out to examinate the effect of aging period on chromatic, chemical and organoleptic characteristics, and to evaluate of optimum aging period for each grade in flue-cured leaf tobacco. The leaf tobaccos were produced in 2000, and threshed, redried and packed in carton box under the current methods. Four grades of processed leaf(A3O, B1O, C1L and D3L) were stored during 24 months(May 10, 2001 to April 31, 2003) in warehouse of Chungju Leaf Tobacco Processing Factory. The leaf tobaccos were sampled at three month intervals for analysis of chromatic, chemical and organoleptic properties. Yellow(b), pH values and total sugar contents of four grades were significantly decreased during the aging. Filling values, tar, nicotine and CO contents of tobacco smoke, and puff number of cigarettes were not significantly changed during the aging. Positive correlation coefficients were significantly observed between taste and irritation of the calculated attributes from contents of volatile oil components in leaf tobacco and those of the panel sensory attributes. The ratio of maximum change in taste attribute was larger than that in irritation attribute during aging. The optimum aging periods estimated by taste for A3O, B1O, C1L and D3L were 17.8, 14.9, 10.8, and 9.8 months, respectively. The thin leaf(Primings and Cutters) undergo satisfactory aging earlier as compared to bodied leaf(Leaf and Tips). The results suggest that decrease of aging period for thin leaf from 18～21 to 9～12 months may be beneficial to save storage cost in flue-cured tobacco.

• 한국광학회지
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• 제11권4호
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• pp.232-238
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• 2000

백색 시준광의 시준 정도로 정밀하게 측정하기 위하여 두 직선격자나 원형격자에 의한 버니어(vernier) 무아레 무늬를 이용하는 새로운 시준 방법을 제안하였다. 버니아 무아레 무늬의 피치 간격을 측정함으로써 렌즈의 초점 종이동 오차($\Deltaf$), 발산각($\theta$) 및 종색수차 $(L_{ch})$ 를 구하였다. 초점 길이가 120.0mm이고 F/2.4인 렌즈를 사용하여 측정한 결과 $\Deltaf$=2.19mm이고 $\theta$=mm이고 F/1.6 그리고 아베수가 64.1인 렌즈의 종색수차를 버니어 무아레 무늬를 이용하여 측정하였다. 자동초점방법을 이용하여 측정한 결과,$L_{ch}=1.58mm(\pm0.01mm)$와 무아레 간섭법을 이용하여 측정한 결과인 1.59mm($\pm$0.1mm)와 거의 일치함을 알 수 있었다.

• Journal of applied mathematics & informatics
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• 제19권1_2호
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• pp.127-133
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• 2005

An f-coloring of a graph G = (V, E) is a coloring of edge set E such that each color appears at each vertex v $\in$ V at most f(v) times. The minimum number of colors needed to f-color G is called the f-chromatic index $\chi'_f(G)$ of G. Any graph G has f-chromatic index equal to ${\Delta}_f(G)\;or\;{\Delta}_f(G)+1,\;where\;{\Delta}_f(G)\;=\;max\{{\lceil}\frac{d(v)}{f(v)}{\rceil}\}$. If $\chi'_f(G)$= ${\Delta}$f(G), then G is of $C_f$ 1 ; otherwise G is of $C_f$ 2. In this paper, the classification problem of complete graphs on f-coloring is solved completely.

• Journal of the Optical Society of Korea
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• 제1권2호
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• pp.74-80
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• 1997

300mm F/4.0 telephotolens with diffractive hybrid lens was designed, and its optical performance was tested and compared with a traditional lens system. DOE(Diffractive Optical Element) reconstructs wavefronts using wave phenomena of light to focus the incident light onto the focal point and has negative Abbe number while a traditional lens uses geometrical phenomena of light and has positive Abbe number. Therefore, a diffractive hybrid lens containing both refractive and diffractive elements can remarkably correct chromatic aberration and spherical aberration of an optical system. We investigated and analyzed the optical properties of a diffractive hybrid lens for the visible spectrum, and we used a difractive hybrid lens to design and evaluate a 300mm F/4.0 telephotolens without the special LD(Low Dispersive) glass lens which is costly and difficult to manufacture. Most traditional telephotolenses use the special LD glass for chromatic aberration correcton. Optical performance tests such as resolution and characteristics of aberration of both lens systems using a diffractive hybrid lens and traditional lens were performed.

• 한국인터넷방송통신학회논문지
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• 제15권1호
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• pp.269-276
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• 2015

본 논문은 지금까지 미해결 문제로 알려진 정점 색칠 문제에 대한 Erd$\ddot{o}$s-Faber-Lov$\acute{a}$sz 추측을 증명하였다. Erd$\ddot{o}$s-Faber-Lov$\acute{a}$sz 추측은 "k개의 $K_k$-클릭 합 교차 그래프는 k개의 색으로 칠할 수 있다". 즉, x(G)=k이다". Erd$\ddot{o}$s-Faber-Lov$\acute{a}$sz 추측을 증명하기 위해 본 논문은 교차되는 정점수와 한 정점에서 교차되는 클릭수를 구하여 모두 짝수이면 그래프의 최소 차수 ${\delta}(G)$ 정점을 최대독립집합 (minimum Independent set, MIS)에 포함시키는 방법을 적용하고, 둘 중 어느 하나가 홀수이면 최대 차수 ${\Delta}(G)$ 정점을 MIS에 포함시키는 방법을 적용하였다. 알고리즘 수행결과 얻은 MIS 개수가 x(G)=k이다. $3{\leq}k{\leq}8$인 $K_k$-클릭 합 교차 그래프에 대해 실험한 결과 모든 그래프에서 x(G)=k를 얻는데 성공하였다. 결국, "k개의 $K_k$-클릭 합 교차 그래프는 k개의 색으로 칠할 수 있다".는 Erd$\ddot{o}$s-Faber-Lov$\acute{a}$sz 추측은 성립함을 증명하였다.

• Korean Journal of Mathematics
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• 제28권3호
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• pp.405-419
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• 2020

The zeroth-order general Randić index ⁰R_α(G) of the graph G is defined as ∑_u∈V(G)d(u)^α, where d(u) is the degree of vertex u and α is an arbitrary real number. In this paper, the maximum value of zeroth-order general Randić index on the graphs of order n with a given clique number is presented for any α ≠ 0, 1 and α ∉ (2, 2n-1], where n = |V (G)|. The minimum value of zeroth-order general Randić index on the graphs with a given clique number is also obtained for any α ≠ 0, 1. Furthermore, the corresponding extremal graphs are characterized.

• 대한수학회보
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• 제52권5호
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• pp.1423-1431
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• 2015

A clique-transversal set D of a graph G is a set of vertices of G such that D meets all cliques of G. The clique-transversal number is the minimum cardinality of a clique-transversal set in G. For every cubic graph with at most two bridges, we first show that it has a perfect matching which contains exactly one edge of each triangle of it; by the result, we determine the exact value of the clique-transversal number of line graph of it. Also, we present a sharp upper bound on the clique-transversal number of line graph of a cubic graph. Furthermore, we prove that the clique-transversal number of line graph of a triangle-free graph is at most the chromatic number of complement of the triangle-free graph.

• Journal of applied mathematics & informatics
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• 제24권1_2호
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• pp.357-366
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• 2007

Let G(V, E) be a simple graph, and let f be an integer function on V with $1{\leq}f(v){\leq}d(v)$ to each vertex $v{\in}V$. An f-edge cover-coloring of a graph G is a coloring of edge set E such that each color appears at each vertex $v{\in}V$ at least f(v) times. The f-edge cover chromatic index of G, denoted by ${\chi}'_{fc}(G)$, is the maximum number of colors such that an f-edge cover-coloring of G exists. Any simple graph G has an f-edge cover chromatic index equal to ${\delta}_f\;or\;{\delta}_f-1,\;where\;{\delta}_f{=}^{min}_{v{\in}V}\{\lfloor\frac{d(v)}{f(v)}\rfloor\}$. Let G be a connected and not complete graph with ${\chi}'_{fc}(G)={\delta}_f-1$, if for each $u,\;v{\in}V\;and\;e=uv{\nin}E$, we have ${\chi}'_{fc}(G+e)>{\chi}'_{fc}(G)$, then G is called an f-edge covered critical graph. In this paper, some properties on f-edge covered critical graph are discussed. It is proved that if G is an f-edge covered critical graph, then for each $u,\;v{\in}V\;and\;e=uv{\nin}E$ there exists $w{\in}\{u,v\}\;with\;d(w)\leq{\delta}_f(f(w)+1)-2$ such that w is adjacent to at least $d(w)-{\delta}_f+1$ vertices which are all ${\delta}_f-vertex$ in G.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2003년도 춘계학술대회
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• pp.135-141
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• 2003

An experiment was conducted to identify salient colours for information coding at electronic video displays. CRT and TFT-LCD were used to evaluate the effect of different types of electronic displays on the salience of colours. Total of 100 Subjects, 50 for each display were asked to select more salient 10 colours among 24 given colours. There was no statistically significant difference in the salience of colours between the two display types. The result showed that the tested colours could be clustered into 5 categories according to their brightness, saturation, and the number of R, G, B elements occupied to reproduce the colours. Three achromatic colours (black, white, grey) and eight chromatic colors (red, yellow, green, blue, cyan, orange, magenta, and indigo) were identified as the salient colours at the electronic video displays. The result also showed that the eight chromatic colours could be clustered into two distinct categories, landmark colours(red, yellow, green, and blue) and the other basic colours (cyan, magenta, orange, and indigo). It is noticeable that cyan, magenta, and indigo substituted for pink, purple, and brown that were recommended as the salient colours for the environment not using electronic video displays by the previous researches.

• 한국수학교육학회지시리즈A:수학교육
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• 제10권2호
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• pp.4-8
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• 1972

We consider the class (equation omitted) of all k-degenerate graphs, for k a non-negative integer. The class (equation omitted) and (equation omitted) are exactly the classes of totally disconnected graphs and of forests, respectively; the classes (equation omitted) and (equation omitted) properly contain all outerplanar and planar graphs respectively. The advantage of this view point is that many of the known results for chromatic number and point arboricity have natural extensions, for all larger values of k. The purpose of this note is to show that a graph G is (P$^3$)-realizable if G is planar and 3-degenerate.