• Journal of the Korean Mathematical Society
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• v.40 no.2
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• pp.179-193
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• 2003

The braid-permutation group is a group of welded braids which is the extension of Artin's braid groups by the symmetric groups. It is also described as a subgroup of the automorphism group of a free group. We also show that the plus-construction of the classifying space of the infinite braid-permutation group has the following two types of splittings BBP(equation omitted) B∑(equation omitted) $\times$ X, BBP(equation omitted) B $^{＋}$$\times$ Y＝S$^1$$\times$Y, where X, Y are some spaces.

• Journal of the Chungcheong Mathematical Society
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• v.23 no.3
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• pp.555-561
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• 2010

For the pure braid groups, this paper gives a positive finite presentation whose generators are the standard Artin generators, and determines whether the submonoid generated by the Artin generators is a Garside monoid or not.

• Journal of the Korean Mathematical Society
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• v.50 no.4
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• pp.865-877
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• 2013

The disjoint union of mapping class groups of surfaces forms a braided monoidal category $\mathcal{M}$, as the disjoint union of the braid groups $\mathcal{B}$ does. We give a concrete and geometric meaning of the braidings ${\beta}_{r,s}$ in $\mathcal{M}$. Moreover, we find a set of elements in the mapping class groups which correspond to the standard generators of the braid groups. Using this, we can define an obvious map ${\phi}\;:\;B_g{\rightarrow}{\Gamma}_{g,1}$. We show that this map ${\phi}$ is injective and nongeometric in the sense of Wajnryb. Since this map extends to a braided monoidal functor ${\Phi}\;:\;\mathcal{B}{\rightarrow}\mathcal{M}$, the integral homology homomorphism induced by ${\phi}$ is trivial in the stable range.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.11 no.3
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• pp.13-22
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• 2001

The notion of pseudorandomness plays an important role in modem cryptography as well as computer science. We show a simple and practical construction of a pseudorandom generator based on the intractability of the problem in braid groups. The generator is proved as secure as a hard instance of a variant of the conjugacy problem.

• Korean Journal of Mathematics
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• v.19 no.4
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• pp.409-421
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• 2011

We study a natural map from the braid group to the mapping class group which is called Harer map. It is rather new and different from the classical map which was studied in 1980's by F. Cohen, J. Harer et al. We show that this map is homologically trivial for most coefficients by using the fact that this map factors through the symmetric group.

• Journal of the Korean Mathematical Society
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• v.47 no.3
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• pp.445-454
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• 2010

The braid group $B_n$ maps homomorphically into the Temperley-Lieb algebra $TL_n$. It was shown by Zinno that the homomorphic images of simple elements arising from the dual presentation of the braid group $B_n$ form a basis for the vector space underlying the Temperley-Lieb algebra $TL_n$. In this paper, we establish that there is a dual presentation of Temperley-Lieb algebras that corresponds to the dual presentation of braid groups, and then give a simple geometric proof for Zinno's theorem, using the interpretation of simple elements as non-crossing partitions.

• Journal of Nutrition and Health
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• v.5 no.3
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• pp.127-133
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• 1972

This study was designed to observe the effect of ethanol extracts from fish flour on the nucleic acid metabolism in rats. Young rats, weighing 75-85g were used as the experimental animals and diet used were 8 kinds; diet supplemented with 10% fish flour, diets which were supplemented with the extracts and or remainders of fish flour after extracting by either 76% or 96% ethanol to the rice diet, respectively, and diet supplemented with 6% casein. After feeding corresponding diet for 40 days, RNA and DNA contents, and DNase activities in the liver, kidney and braid were determined. The results obtaioed from this study are summarized as follows: 1. The RNA contents of the ethanol-treatment groups are, in the liver and kidney, similar to, and in the brain, generally higher than, that of the control group. 2. The DNA contents of each organ show no difference between ethanol-treatment groups and control group, but in the liver, of ethanol extrat groups are lower than casein group. 3. the DNase activity of each organ in the ethanol-treatmeut groups, is generally lower than the control group. The above results indicate that ethanol extracts from fish flour have influence on the nucleic acid metabolism.

• The korean journal of orthodontics
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• v.42 no.1
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• pp.39-46
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• 2012

Objective: We evaluated the detachment force, amount of deformation, fracture mode, and pull-out force of 3 different wires used for bonded lingual retainer fabrication. Methods: We tested 0.0215-inch five-stranded wire (PentaOne, Masel; group I), $0.016{\times}0.022$-inch dead-soft eight-braided wire (Bond-A-Braid, Reliance; group II), and 0.0195-inch dead-soft coaxial wire (Respond, Ormco; group III). To test detachment force, deformation, and fracture mode, we embedded 94 lower incisor teeth in acrylic blocks in pairs. Retainer wires were bonded to the teeth and vertically directed force was applied to the wire. To test pull-out force, wires were embedded in composite that was placed in a hole at the center of an acrylic block. Tensile force was applied along the long axis of the wire. Results: Detachment force and mode of fracture were not different between groups. Deformation was significantly higher in groups II and III than in group I (p < 0.001). Mean pull-out force was significantly higher for group I compared to groups II and III (p < 0.001). Conclusions: Detachment force and fracture mode were similar for all wires, but greater deformations were seen in dead-soft wires. Wire pull-out force was significantly higher for five-stranded coaxial wire than for the other wires tested. Five-stranded coaxial wires are suggested for use in bonded lingual retainers.