• Communications of the Korean Mathematical Society
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• v.13 no.1
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• pp.29-36
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• 1998

We show that if M is a $II_1$-factor and a countable discrete group G acts outerly on M then Jones' index $[M:M^G]$ of a pair of $II_1^-factors is equal to the order $\mid$G$\mid$ of G. It is also shown that for a subgroup H of G Jones' index $[M^H:M^G]$ is equal to the group index [G:H] under certain conditions.

• Journal of Korean Institute of Industrial Engineers
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• v.28 no.1
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• pp.36-43
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• 2002

We analyze bulk service $M/G^{b}/1$ queues using the arrival time approach of Chae et al. (2001). As a result, the decomposition property of the M/G/1 queue with generalized vacations is extended to the $M/G^{b}/1$ queue in which the batch size is exactly a constant b. We also demonstrate that the arrival time approach is useful for relating the time-average queue length PGF to that of the departure time, both for the $M/G^{b}/1$queue in which the batch size is as big as possible but up to the maximum of constant b. The case that the batch size is a random variable is also briefly mentioned.

• Food Science and Biotechnology
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• v.15 no.5
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• pp.820-823
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• 2006

Five oligosaccharides were isolated from the hydrolysate of konjac (Amorphophallus konjac) glucomannan by a purified ${\beta}$-mannanase from Trichoderma sp. These oligosaccharides were identified as M-M, G-M, M-G-M, M-G-M-M, and M-G-G-M; where G- and M- represent ${\beta}$-1,4-D-glucopyranosidic and ${\beta}$-1,4-D-mannopyranosidic linkages, respectively. The mode of action of the mannanase on the glucomannan is discussed on the basis of the structure of the above oligosaccharides.

• Bulletin of the Korean Mathematical Society
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• v.46 no.6
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• pp.1079-1089
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• 2009

In this paper, we shall show that for any entire function f, the function of the form $f^m(f^n$ - 1)f' has no non-zero finite Picard value for all positive integers m, n ${\in}\;{\mathbb{N}}$ possibly except for the special case m = n = 1. Furthermore, we shall also show that for any two nonconstant meromorphic functions f and g, if $f^m(f^n$-1)f' and $g^m(g^n$-1)g' share the value 1 weakly, then f $\equiv$ g provided that m and n satisfy some conditions. In particular, if f and g are entire, then the restrictions on m and n could be greatly reduced.

• Journal of the Korean Operations Research and Management Science Society
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• v.41 no.3
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• pp.37-43
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• 2016

This note discusses the inter-loss time ofan M/G/1/1 queuing system. The inter-loss time is defined as the time duration between two consecutive losses of arriving customers. In this study, we present the explicit Laplace transform of the inter-loss time distribution of an M/G/1/1 queuing system.

• Korean Journal of Ecology and Environment
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• v.43 no.2
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• pp.298-306
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• 2010

We estimated aboveground primary productivity of Salix nipponica based on biomass using allometry and basal area at Janghang wetland in Han River estuary. In addition, we estimated secondary production of sesarmine crab (Sesarma dehaani) living under the Salix community to interpret relationships between Salix nipponica and Sesarma dehaani. Salix nipponica showed primary productivity of 4,777 g DW $m^{-2}yr^{-1}$, which appear to be the highest primary productivity in South Korea. The estimated amount of autochthonous organic matter from S. nipponica and allochthonous organic matter from the Han River into sediment was 359 g C $m^{-2}yr^{-1}$ and 347 g C $m^{-2}yr^{-1}$, respectively. The secondary productivity of Sesarma dehaani was 100.2 g FW $m^{-2}yr^{-1}$, which was 2.1% of the primary productivity of S. nipponica. The biomass of Sesarma dehanni was average 140 g FW $m^{-2}$, which consumed their prey of approximately 2,140 g FW $yr^{-1}$, which is equivalent to approximately 208 g C $m^{-2}yr^{-1}$.

• Natural Product Sciences
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• v.4 no.2
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• pp.62-67
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• 1998

As a part of search for new biologically active constituents from aloe, we have isolated a glycopeptide, called G1G1M1DI2, from the gel(G1) of Aloe vera. Chemical and spectroscopic evidence indicated that G1G1M1DI2 is a glycopeptide. The molecular weight of G1G1M1DI2 was about 5,500 daltons, and the carbohydrate and protein contents were 20.9% and 32.6%, respectively. Periodate oxidation and enzymic degradation gave peptide moiety and carbohydrate moiety, respectively. Carbohydrate moiety is composed of fucose, galactose, glucose and mannose in a molar ratio of 0.5:2.4;48.8:48.3. Peptide moiety is composed of fifteen amino acids, and glutamic acid and glycine were the major componants. The glycopeptide, G1G1M1DI2, stimulated thymidine uptake of SCC 13 cells about 6.5 times the control. This result suggests that this glycopeptide has a skin cell proliferating activity.

• Journal of the Korean Electrochemical Society
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• v.19 no.4
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• pp.129-133
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• 2016

In this study, a polymer-carbon composite material is prepared for environmental-friendly organic anode. On poly(styrenesulfonate)(PSS)-carbon composite anode, the carbon is coated by PSS as a core-shell structure and the PSS-carbon composite anode has $524mAh\;g^{-1}$ theoretical capacity with <0.6V voltage. Moreover, the PSS-carbon composite anode shows $519.6mAh\;g^{-1}$, $461.2mAh\;g^{-1}$, $411.8mAh\;g^{-1}$ and $315.9mAh\;g^{-1}$ discharge capacities at 0.1, 0.5, 1 and 10 C, respectively, and stable cycle performance up to 30 cycles. The PSS-carbon composite anode, containing polystyrene and sulfonate functional groups, is suitable for high electrochemical properties organic rechargeable battery.

• Journal of the Korean Mathematical Society
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• v.45 no.6
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• pp.1613-1622
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• 2008

Let G be a graph with vertex set V(G) and edge set E(G), and let g, f be two nonnegative integer-valued functions defined on V(G) such that $g(x)\;{\leq}\;f(x)$ for every vertex x of V(G). We use $d_G(x)$ to denote the degree of a vertex x of G. A (g, f)-factor of G is a spanning subgraph F of G such that $g(x)\;{\leq}\;d_F(x)\;{\leq}\;f(x)$ for every vertex x of V(F). In particular, G is called a (g, f)-graph if G itself is a (g, f)-factor. A (g, f)-factorization of G is a partition of E(G) into edge-disjoint (g, f)-factors. Let F = {$F_1$, $F_2$, ..., $F_m$} be a factorization of G and H be a subgraph of G with mr edges. If $F_i$, $1\;{\leq}\;i\;{\leq}\;m$, has exactly r edges in common with H, we say that F is r-orthogonal to H. If for any partition {$A_1$, $A_2$, ..., $A_m$} of E(H) with $|A_i|=r$ there is a (g, f)-factorization F = {$F_1$, $F_2$, ..., $F_m$} of G such that $A_i\;{\subseteq}E(F_i)$, $1\;{\leq}\;i\;{\leq}\;m$, then we say that G has (g, f)-factorizations randomly r-orthogonal to H. In this paper it is proved that every (0, mf - (m - 1)r)-graph has (0, f)-factorizations randomly r-orthogonal to any given subgraph with mr edges if $f(x)\;{\geq}\;3r\;-\;1$ for any $x\;{\in}\;V(G)$.

• Korean Journal of Plant Resources
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• v.25 no.4
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• pp.363-371
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• 2012

Sambucus williamsii var. coreana have been used as a traditional medical food. This research was conducted to investigate the antioxidants of S. williamsii var. coreana leave and stem extracts. Total phenolic content of S. williamsii var. coreana leaves and stem water extracts were 6.6 and 2.0 mg/mL. The EDA by DPPH free radical scavenging test of S. williamsii var. coreana leaves extracts were 99.5 and 89.7% in water and ethanol extracts contained phenolic 200 ${\mu}g/mL$. The stem extracts were 92.2 and 94.3% in water and ethanol extracts contained phenolic 200 ${\mu}g/mL$. The ABTS radical decolorization activity of water and ethanol extracts from leaves were 79.8 and 99.1% at phenolic 200 ${\mu}g/mL$ and water and ethanol extracts from stem were 90.8 and 97.2% at phenolic 200 ${\mu}g/mL$. The antioxidant protection factor of water and ethanol extracts from leaves were 1.1 PF and 1.1 PF at phenolic 200 ${\mu}g/mL$ and water and ethanol extracts from stem were 1.4 PF and 1.0 PF at phenolic 200 ${\mu}g/mL$. The TBARs of water and ethanol extracts from leaves were 88.7 and 98.1% at phenolic 200 ${\mu}g/mL$ and water and ethanol extracts from stem were 93.6 and 90.6% at phenolic 200 ${\mu}g/mL$. The antioxidative activities of extracts from S. williamsii var. coreana leaves and stem were higher than BHT as positive control. These results suggests that S. williamsii var. coreana extracts have the greatest property as a natural antioxidative source.