• Bulletin of the Korean Mathematical Society
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• v.59 no.1
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• pp.119-139
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• 2022

This paper deals with the λ-labeling and L(2, 1)-coloring of simple graphs. A λ-labeling of a graph G is any labeling of the vertices of G with different labels such that any two adjacent vertices receive labels which differ at least two. Also an L(2, 1)-coloring of G is any labeling of the vertices of G such that any two adjacent vertices receive labels which differ at least two and any two vertices with distance two receive distinct labels. Assume that a partial λ-labeling f is given in a graph G. A general question is whether f can be extended to a λ-labeling of G. We show that the extension is feasible if and only if a Hamiltonian path consistent with some distance constraints exists in the complement of G. Then we consider line graph of bipartite multigraphs and determine the minimum number of labels in L(2, 1)-coloring and λ-labeling of these graphs. In fact we obtain easily computable formulas for the path covering number and the maximum path of the complement of these graphs. We obtain a polynomial time algorithm which generates all Hamiltonian paths in the related graphs. A special case is the Cartesian product graph K_n☐K_n and the generation of λ-squares.

• Korean Journal of Plant Resources
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• v.11 no.3
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• pp.257-263
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• 1998

Fifteen varieties of Oryza sativa mainly includig those of Korean native rice were exactly cutted into three layers such as L$_1$ layer (the outer part of 90% from rice center), L$_2$ layer(the part of 81 ~ 91% from the rice center) and L$_3$ layer(the inner part of 80% from the rice center) and ferulic acid derivatives, which play an important role of antioxidative action, were quantitiavely analyzed by UV absorption spectrometric method at fixed 314nm. From this experiment, it was found that the more it enters from the surface into the rice center, the more those secondary metabolites contents were highly reduced. The varieties showing contents more than 20 mg/g were as follows: Hwasunchalbyeo(25.8mg/g), Jojeongdo(24.1mg/g), Suwon425(21.2mg/g), Daigolbyeo(20.6mg/g) and Nonglimna 1(20.2mg/g) by this order. Estimation onthe anthocyanin contents of both Suwon 425 and Sanghehanghyeolna revealed that its total. contents were very exactly close each other. However, it was charateristically differentiated in the contents of L$_2$ layer with respect to showing a considerably higher content of Suwon 425 than of Sanghaehanghyeolna. Conclusively, the selected Suwon 425 variety, which is coloured and flavour volatile one, showed relatively higher contents of anthocyanin, ferulic acid derivatives in the L$_2$ layer as well as L$_1$ layer when compared with Sanghaehangyeolna and even other varieties. This fact suggested that Suwon 425 could be a promising candidate for the development of health rice food.

• Journal of Apiculture
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• v.33 no.4
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• pp.297-301
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• 2018

Hawthorn is widely distributed in Korea and has been used as herbal medicine for treating various cardiovascular disease, arteriosclerosis and hypertension in Korea. In order to select superior honey tree plant from Korea, the free sugar and organic acid in hawthorn fruits, including five Korean clones and four Chinese cultivars, were evaluated. We also compared these hawthorn fruits of five clones (selected from different area of Korea) with Chinese hawthorn cultivars. Glucose, galactose, fructose and sucrose were the major sugar components of hawthorn. In this study, we observed that sucrose, glucose and fructose content. The highest sucrose content of hawthorn fruit was 188.12g/100g in Daegeumseong cultivar. The sweetness index, which plays important role of taste, was also calculated from the content of sucrose, glucose and fructose. The contribution of each carbohydrate was calculated, based on the fact that fructose is 2.30 and sucrose 1.35 times sweeter than glucose. The highest sweetness of hawthorn fruit was 579.52 in Pocheon clone. Main organic acid detected in hawthorn fruit were citric acid, malic acid and shikimic acid. The highest citric acid and malic acid content in hawthorn fruit were 157.50g/100g (Pocheon 3) and 34.12g/100g (Daegeumseong), respectively. The results of this study would be helpful for using food and functional food products, due to the beneficial effects of free sugar and organic acid for human health such as antioxidants and anticarcinogenic properties.

• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.315-322
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• 2004

Several arguments have been presented in the literature to support the connection between radio halos and cluster mergers. The spectral index distributions of the halos in A665 and A2163 provide a new strong confirmation of this connection, i.e. of the fact that the cluster merger plays an important role in the energy supply to the radio halos. Features of the spectral index (flattening and patches) are indication of a complex shape of the radiating electron spectrum, and are therefore in support of electron reacceleration models. Regions of flatter spectrum are found to be related to the recent merger. In the undisturbed cluster regions, instead, the spectrum steepens with the distance from the cluster center. The plot of the integrated spectral index of a sample of halos versus the cluster temperature indicates that clusters at higher temperature tend to host halos with flatter spectra. This correlation provides further evidence of the connection between radio emission and cluster mergers.

• Bulletin of the Korean Mathematical Society
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• v.36 no.4
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• pp.671-682
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• 1999

Using a base-point free version of the infinite symmetric product we define a fibrewise infinite symmetric product for any fibration $E\;\longrightarrow\;B$. The construction works for any commutative ring R with unit and is denoted by $R_f(E)\;l\ongrightarrow\;B$. For any pointed space B let $G_I(B)\;\longrightarrow\;B$ be the i-th Ganea fibration. Defining $M_R-cat(B):= inf{i\midR_f(G_i(B))\longrihghtarrow\;B$ admits a section} we obtain an approximation to the Lusternik-Schnirelmann category of B which satisfies .g.a product formula. In particular, if B is a 1-connected rational space of finite rational type, then $M_Q$-cat(B) coincides with the well-known (purely algebraically defined) M-category of B which in fact is equal to cat (B) by a result of K.Hess. All the constructions more generally apply to the Ganea category of maps.

• Journal of the military operations research society of Korea
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• v.15 no.2
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• pp.94-104
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• 1989

The concept of Algebraic-Coded Cryptosystem has been proposed recently but its application has not been developed yet. The primary object of this paper is to implement the Private-Key Algebraic-Coded Cryptosystem by using the primitive binary BCH codes. In the analysis of the cryptosystein, we find out the fact that there may exist other key pairs $S_i\;and\;P_i$ satisfying $G^*=S_{i},G_{s},P_{i}$ where $SG_{s}P$ is the original cryptosystem made by use of the systematic code generation matrix $G_{s}$.

• Mass Spectrometry Letters
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• v.2 no.3
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• pp.73-75
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• 2011

In the collisionally-activated dissociation of the proton-bound cluster ions of DNA base guanine (G) and cytosine (C), $G{\bullet}{\bullet}H^+{\bullet}{\bullet}C$, the abundance of [$CH^+$] ions was found to be higher than that of [$GH^+$] despite the fact that G has a higher proton affinity than C. This unexpected observation seems to demonstrate another example that the simple kinetic method scheme does not work. We suggest that a kinetic factor or detailed dynamics governing the proton transfer and dissociation should be carefully considered in the applications of the kinetic method to the proton affinity measurements.

• Bulletin of the Korean Mathematical Society
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• v.29 no.1
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• pp.153-163
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• 1992

Carlitz module is used to study abelian extensions of K=$F_{q}$(T). In number theory every abelian etension of Q is contained in a cyclotomic field. Similarly every abelian extension of $F_{q}$(T) with some condition on .inf. is contained in a cyclotomic function field. Hence the study of cyclotomic function fields in analogy with cyclotomic fields is an important subject in number theory. Much are known in this direction such as ring of integers, class groups and units ([G], [G-R]). In this article we are concerned with the ring of integers in a cyclotomic function field. In [G], it is shown that the ring of integers is generated by a primitive root of the Carlitz module using the ramification theory and localization. Here we will give another proof, which is rather elementary and explicit, of this fact following the methods in [W].[W].

• 제어로봇시스템학회:학술대회논문집
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• 1988.10b
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• pp.943-946
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• 1988

A simple method is proposed for determining the frequency response function G(j.omega.) of a system using a pair of characteristic M-sequences (maximum length linear feed back shift register sequence). When a characteristic M-sequence is sampled with q$_{1}$ and q$_{2}$ both of which are coprime with N, where N is the period of the M-sequence, the obtained pair of sequences have conjugate complex frequency spectrum. Making use of this fact, two charcteristic M-sequences having conjugate complex frequency spectrum are applied to a system to be measured. Since the magnitude of spectrium of M-sequence is known, the gain of G(j.omega.) is directly obtained from the Fourier transform of the system output. The phase of G(j.omega.) is obtained simply by taking the average of the two phases of output spectrum.

• Journal of Biomedical Engineering Research
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• v.2 no.1
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• pp.21-30
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• 1981

In this study, measuring eye movements with E.O.G. to targets beyond 20$^{\circ}$ from fixation point, results are as follows. (1) When the eyes turn toward targets of more than 20$^{\circ}$ eccentricity, the first saccadic eye movement falls short of the target. The presence of image of the target off the fovea(visual error signal) subsequent to such an undershoot elicits, after short interval, corrective saccadic eye movements(usually one) which place the image of the target on the fovea. (2) There are different programming modes at retina for eye movement to targets within and beyond 20$^{\circ}$ from the fixation point. (3) Saccadic system, preparing the direction and amplitude of eye movement completes the corrective saccadic eye movements. (4) Distribution of latency and intersaccadic interval(I.S.I.)are frequently multi modal, with a seperation between modes of 25[msec]. (5) There are two types of saccadic eye movements for the double-step targets. This fact suggests that the visual information is sampled stochastically. (6) The new model of saccadic system including the dissociation of visual functions dependent on retinal eccentricity is required.