• Journal of applied mathematics & informatics
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• v.24 no.1_2
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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.

• Journal of the Korean Society of Systems Engineering
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• v.5 no.1
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• pp.7-20
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• 2009

This paper describes a case study on the R&D programs of fighter and attacker aircraft such as F-22A, F/A-18E/F, and T/A-50. F-22A and F/A-18E/F were developed in same age. The performance of each program was, however extremely different. F-22A program results in a lot of cost overrun and schedule delay. On the other hand F/A-18E/F program met the cost, schedule, and performance goals. In the T/A-50 program with a super-sonic advanced trainer, T-50 was also developed successfully on planned cost and time by Korea Air-force and KAI. This paper derives key elements for the success of the military aircraft R&D program through lessons learned from th e case study. Each program is analyzed in terms of its background, planning and management.

• Mycobiology
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• v.39 no.4
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• pp.243-248
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• 2011

The ubiquitin-proteasome system is one of the major protein turnover mechanisms that plays important roles in the regulation of a variety of cellular functions. It is composed of E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3 ubiquitin ligases that transfer ubiquitin to the substrates that are subjected to degradation in the 26S proteasome. The Skp1, Cullin, F-box protein (SCF) E3 ligases are the largest E3 gene family, in which the F-box protein is the key component to determine substrate specificity. Although the SCF E3 ligase and its F-box proteins have been extensively studied in the model yeast Saccharomyces cerevisiae, only limited studies have been reported on the role of F-box proteins in other fungi. Recently, a number of studies revealed that F-box proteins are required for fungal pathogenicity. In this communication, we review the current understanding of F-box proteins in pathogenic fungi.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09b
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• pp.147-151
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• 2010

In this study, the clay specimen of Busan-Gyeongnam region was used for unconfined compression test to compare the relationship formula between elasticity modulus at peak($E_f$), elasticity modulus at $q_u$/2($E_{50}$), and cohesion when the sample breaks down by region and by level of cohesion. As the result, the regional results were found to be in the range of $E_f$ = 14c~47c and $E_{50}$ = 43c~137c; by cohesion, the results for very soft ground was $E_f$ = 15c~40c and $E_{50}$ = 54c~101c, $E_f$ = 13c~63c and $E_{50$ = 40c~147c for soft ground, $E_f$ = 18c~47c and $E_{50}$ = 57c~144c for medium ground, and $E_f$ = 25c~45c and $E_{50}$ = 68c~115c for solid ground. The average of the relationship formula between elasticity modulus-cohesion for the clay used in this study was $E_f$ = 32c, $E_{50}$ = 93c. This is 2.5~5 times smaller than the existing relationship formula.

• BMB Reports
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• v.42 no.10
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• pp.691-696
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• 2009

The E2F gene family appears to regulate the proliferation and differentiation of events that are required for adipogenesis. Pref-1 is a transmembrane protein that inhibits adipocyte differentiation in 3T3-L1 cells. In this study, we found that the expression of pref-1 is regulated by the transcription factor E2F1. The expression of pref-1 and E2F1 was strongly induced in preadipocytes and at the late differentiation stage. Using luciferase reporter assay, ChIP assay and EMSA, we found that the -211/-194 region of the pref-1 promoter is essential for the binding of E2F1 as well as E2F1-dependent transcriptional activation. Knockdown of E2F1 reduced both pref-1 promoter activity and the level of pref-1 mRNA. Taken together, our data suggest that transcriptional activation of pref-1 is stimulated by E2F1 protein in adipocytes.

• Clinical and Experimental Reproductive Medicine
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• v.20 no.2
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• pp.157-160
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• 1993

The human follicular f1uids(F.F.) may be considered to contribute the maturation of the oocytes on the in vitro culture. To investigate the effects of epidermal growth factor (E.G.F.), which is present in mature and immature follicular fluids, we had experiments of mouse oocytes maturation in vitro. The endpoints assayed were rated as percentage of oocytes undergoing germinal vesicle breakdown(G.V.B.D.) and polar body(P.B.) formation at 12 hours after in vitro culture. The rates of G.B.B.D. were 87% in mature F.F. 68% in immature F.F. and 78% in Ham's F-10 medium respectively. And overall the mature F.F. seem to stimulate on in vitro oocyte maturation compared with either immature F.F. or Ham's F-10 medium. As the concentration of addition of E.G.F. in immature F.F., the rates of G.V.B.D. and P.B. formation were 82 %, 23% in addition with 2 ng/ml while 84%, 32% in addition with 4 ng/ml respectivly. And at the concentration of addition of E.G.F. in Ham's F-10 media as well, the rates of G.V.B.D. and P.B. formation were 84%, 40% and 82%, 44% in addition with each 2ng, 4ng. AccordinglY there was no influence on the oocytes maturation at the addition of E.G.F. to each immature F.F. and Ham's F-10 medium. In conclusion, the E.G.F. is not able to induce oocyte maturation independent of it's effects in immature F.F. and Ham's F-10 media.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.2
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• pp.380-389
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• 2005

The Goldschmidt iterative algorithm for a floating point divide calculates it by performing a fixed number of multiplications. In this paper, a variable latency Goldschmidt's divide algorithm is proposed, that performs multiplications a variable number of times until the error becomes smaller than a given value. To calculate a floating point divide '$\frac{N}{F}$', multifly '$T=\frac{1}{F}+e_t$' to the denominator and the nominator, then it becomes ’$\frac{TN}{TF}=\frac{N_0}{F_0}$'. And the algorithm repeats the following operations: ’$R_i=(2-e_r-F_i),\;N_{i+1}=N_i{\ast}R_i,\;F_{i+1}=F_i{\ast}R_i$, i$\in${0,1,...n-1}'. The bits to the right of p fractional bits in intermediate multiplication results are truncated, and this truncation error is less than ‘$e_r=2^{-p}$'. The value of p is 29 for the single precision floating point, and 59 for the double precision floating point. Let ’$F_i=1+e_i$', there is $F_{i+1}=1-e_{i+1},\;e_{i+1}',\;where\;e_{i+1}, If '$[F_i-1]<2^{\frac{-p+3}{2}}$ is true, ’$e_{i+1}<16e_r$' is less than the smallest number which is representable by floating point number. So, ‘$N_{i+1}$ is approximate to ‘$\frac{N}{F}$'. Since the number of multiplications performed by the proposed algorithm is dependent on the input values, the average number of multiplications per an operation is derived from many reciprocal tables ($T=\frac{1}{F}+e_t$) with varying sizes. 1'he superiority of this algorithm is proved by comparing this average number with the fixed number of multiplications of the conventional algorithm. Since the proposed algorithm only performs the multiplications until the error gets smaller than a given value, it can be used to improve the performance of a divider. Also, it can be used to construct optimized approximate reciprocal tables. The results of this paper can be applied to many areas that utilize floating point numbers, such as digital signal processing, computer graphics, multimedia, scientific computing, etc

• Communications of the Korean Mathematical Society
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• v.23 no.2
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• pp.153-159
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• 2008

For $\mathbb{F}[e^{{\pm}x}]_{\{{\partial}\}}$, all the derivations of the evaluation algebra $\mathbb{F}[e^{{\pm}x}]_{\{{\partial}\}}$ is found in the paper (see [16]). For $M=\{{\partial}_1,\;{\partial}_1^2\},\;Der_{non}(\mathbb{F}[e^{{\pm}x}]_M))$ of the evaluation algebra $\mathbb{F}[e^{{\pm}x},\;e^{{\pm}y}]_M$ is found in the paper (see [2]). For $M=({\partial}_1^2,\;{\partial}_2^2)$, we find $Der_{non}(\mathbb{F}[e^{{\pm}x},\;e^{{\pm}y}]_M))$ of the evaluation algebra $\mathbb{F}[e^{{\pm}x},\;e^{{\pm}y}]_M$ in this paper.

• Honam Mathematical Journal
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• v.28 no.2
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• pp.197-204
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• 2006

For the evaluation algebra $F[e^{{\pm}{\chi}}]_M$, if M={$\partial$}, the automorphism group $Aut_{non}$($F[e^{{\pm}{\chi}}]_M$) and $Der_{non}$($F[e^{{\pm}{\chi}}]_M$) of the evaluation algebra $F[e^{{\pm}{\chi}}]_M$ are found in the paper [12]. For M={${\partial}^n$}, we find $Aut_{non}$($F[e^{{\pm}{\chi}}]_M$) and $Der_{non}$($F[e^{{\pm}{\chi}}]_M$) of the evaluation algebra $F[e^{{\pm}{\chi}}]_M$ in this paper. We show that a derivation of some non-associative algebra is not inner.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.11 no.2
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• pp.9-14
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• 2007

A signed 3-partite graph is a 3-partite graph in which each edge is assigned a positive or a negative sign. Let G(U, V, W) be a signed 3-partite graph with $U\;=\;\{u_1,\;u_2,\;{\cdots},\;u_p\},\;V\;=\;\{v_1,\;v_2,\;{\cdots},\;v_q\}\;and\;W\;=\;\{w_1,\;w_2,\;{\cdots},\;w_r\}$. Then, signed degree of $u_i(v_j\;and\;w_k)$ is $sdeg(u_i)\;=\;d_i\;=\;d^+_i\;-\;d^-_i,\;1\;{\leq}\;i\;{\leq}\;p\;(sdeg(v_j)\;=\;e_j\;=\;e^+_j\;-\;e^-_j,\;1\;{\leq}\;j\;{\leq}q$ and $sdeg(w_k)\;=\;f_k\;=\;f^+_k\;-\;f^-_k,\;1\;{\leq}\;k\;{\leq}\;r)$ where $d^+_i(e^+_j\;and\;f^+_k)$ is the number of positive edges incident with $u_i(v_j\;and\;w_k)$ and $d^-_i(e^-_j\;and\;f^-_k)$ is the number of negative edges incident with $u_i(v_j\;and\;w_k)$. The sequences ${\alpha}\;=\;[d_1,\;d_2,\;{\cdots},\;d_p],\;{\beta}\;=\;[e_1,\;e_2,\;{\cdots},\;e_q]$ and ${\gamma}\;=\;[f_1,\;f_2,\;{\cdots},\;f_r]$ are called the signed degree sequences of G(U, V, W). In this paper, we characterize the signed degree sequences of signed 3-partite graphs.