• Journal of The Korean Society of Integrative Medicine
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• v.10 no.4
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• pp.93-102
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• 2022

Purpose : The purpose of this study was to analyze the change in thickness of transvers abdominis, internal oblique, and external oblique when virtual reality based ring fit adventure is applied to young adults in order to investigate the effect of ring fit adventure on core stabilization. Methods : 30 subjects participated in the experiment. Subjects were randomly assigned to two groups. 15 subjects performed ring fit adventure core exercise (experimental group) and 15 subjects bridge and dead bug exercise (control group). The ring fit adventure core exercise program consists of 6 types, 1) bow pull, 2) overhead lunge twist, 3) pendulum bend, 4) seated ring raise, 5) plank, 6) warrior III pose. Each exercise was performed for 5 minutes, for a total of 30 minutes. The bridege and dead bug exercise were performed for 15 minutes each for a total of 30 minutes. All interventions were performed 3 times a week for 4 weeks. Thickness of the abdominal muscles was measured with a ultrasound. The paired t-test was used to compare the thickness of the transverse abdominis, internal oblique, and external oblique before and after intervention, and the comparison between groups was analyzed using the independent t-test. Results : As a result, in the experimental group, thickness of transverse abdominis and internal oblique increased significantly (p<.05), but external oblique decreased significantly (p<.05), and in the control group, thickness of transverse abdominis, internal oblique, and external oblique increased significantly (p<.05). There was a significant difference in external oblique in the difference between groups (p<.05). Conclusion : These study results showed that core exercise using ring fit adventure can reduce external oblique and increased selective muscle activity of transverse abdominis and internal oblique of the deep abdominal muscles, so it is meaningful as an effective intervention for core stabilization.

• Kyungpook Mathematical Journal
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• v.49 no.3
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• pp.451-456
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• 2009

Let R be a ring. We give some new characterizations of QF under the special annihilators condition. Some known results are obtained as corollaries.

• Journal of the Korean Wood Science and Technology
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• v.45 no.5
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• pp.661-670
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• 2017

50-year tree-ring ${\delta}^{18}O$ chronologies (1966~2015) for principle conifer tree species (Taxus cuspidata, Pinus koraiensis, Abies koreana) and Quercus mongolica at subalpine zone in Mt. Jiri were established. The establishing of tree-ring ${\delta}^{18}O$ chronologies for each tree species were fulfilled using four trees, which showed the good result in cross-dating. In the comparisons between tree-ring ${\delta}^{18}O$ chronologies within the same tree species all tree species showed reliable results statistically (p < 0.001), and they also showed EPS higher than 0.85. In addition to, the reliable correlations (p < 0.001) were verified between tree-ring ${\delta}^{18}O$ chronologies of four tree species, as well. In the response function analysis in order to investigate the relationships between tree-ring ${\delta}^{18}O$ chronologies and corresponding climatic factors, i.e., monthly precipitation and mean temperature, T. cuspidata showed a negative correlation with May precipitation (p < 0.05) and A. koreana showed a negative correlation with April precipitation (p < 0.05). If long tree-ring ${\delta}^{18}O$ chronologies of T. cuspidata and A. koreana will be established, it will be possible to reconstruct April and May precipitation in the past when we have no the meteorological data.

• Bulletin of the Korean Mathematical Society
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• v.46 no.5
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• pp.867-871
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• 2009

A module M over a ring R is said to satisfy (P) if every generating set of M contains an independent generating set. The following results are proved; (1) Let $\tau$ = ($\mathbb{T}_\tau,\;\mathbb{F}_\tau$) be a hereditary torsion theory such that $\mathbb{T}_\tau$ $\neq$ Mod-R. Then every $\tau$-torsionfree R-module satisfies (P) if and only if S = R/$\tau$(R) is a division ring. (2) Let $\mathcal{K}$ be a hereditary pre-torsion class of modules. Then every module in $\mathcal{K}$ satisfies (P) if and only if either $\mathcal{K}$ = {0} or S = R/$Soc_\mathcal{K}$(R) is a division ring, where $Soc_\mathcal{K}$(R) = $\cap${I 4\leq$ $R_R$ : R/I$\in\mathcal{K}$}.

• Journal of the Chungcheong Mathematical Society
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• v.30 no.1
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• pp.77-102
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• 2017

As an analogy of $Poincar{\acute{e}}$ series in the space of modular forms, T. Ono associated a module $M_c/P_c$ for ${\gamma}=[c]{\in}H^1(G,R^{\times})$ where finite group G is acting on a ring R. $M_c/P_c$ is regarded as the 0-dimensional twisted Tate cohomology ${\hat{H}}^0(G,R^+)_{\gamma}$. In the case that G is the Galois group of a Galois extension K of a number field k and R is the ring of integers of K, the vanishing properties of $M_c/P_c$ are related to the ramification of K/k. We generalize this to arbitrary n-dimensional twisted cohomology of the ring of integers and obtain the extended version of theorems. Moreover, some explicit examples on quadratic and biquadratic number fields are given.

• Journal of the Korean Mathematical Society
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• v.48 no.3
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• pp.627-639
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• 2011

Hopf corings are dened in this work as coring objects in the category of algebras over a commutative ring R. Using the Dieudonn$\'{e}$ equivalences from [7] and [19], one can associate coring structures built from the Hopf algebra $F_p[x_0,x_1,{\ldots}]$, p a prime, with Hopf ring structures with same underlying connected Hopf algebra. We have that $F_p[x_0,x_1,{\ldots}]$ coring structures classify thus Hopf ring structures for a given Hopf algebra. These methods are applied to dene new ring products in the Hopf algebras underlying known Hopf rings that come from connective Morava ${\kappa}$-theory.

• Bulletin of the Korean Chemical Society
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• v.10 no.6
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• pp.500-503
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• 1989

Synthetic studies have been carried out for the addition or substitution of phosphorus nucleophiles to the cation $[(exo-6-R-{\eta}^ {5_-}2-MeO-C_6H_5)Mn(CO)_2NO]PF_6,$ 2. $PPh_3$ reacts with 2 to yield the CO displaced product and $MePPh_2$ attacks the dienyl ring of 2 to yield the phosphonium adduct or the metal to give the CO displaced depending upon the reaction temperatures. Nucleophilic addition of HPPh2 to the dienyl ring of 2 gives a neutral substituted product. $P(OMe)_3$ reacts with 2 to yield a mixture of ring adduct and CO displaced product at room temperature. $At - 20^{\circ}C,\;P(OMe)_3$ attacks the dienyl ring of 2 to give a posphonium adduct, which underwent Arbuzov reaction. This reaction affords a new route to the phosphonate complexes.

• Bulletin of the Korean Mathematical Society
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• v.56 no.1
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• pp.131-150
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• 2019

In this paper, we consider the structure of ${\gamma}$-constacyclic codes of length $2p^s$ over the Galois ring $GR(p^a,m)$ for any unit ${\gamma}$ of the form ${\xi}_0+p{\xi}_1+p^2z$, where $z{\in}GR(p^a,m)$ and ${\xi}_0$, ${\xi}_1$ are nonzero elements of the set ${\mathcal{T}}(p,m)$. Here ${\mathcal{T}}(p,m)$ denotes a complete set of representatives of the cosets ${\frac{GR(p^a,m)}{pGR(p^a,m)}}={\mathbb{F}}p^m$ in $GR(p^a,m)$. When ${\gamma}$ is not a square, the rings ${\mathcal{R}}_p(a,m,{\gamma})=\frac{GR(p^a,m)[x]}{{\langle}x^2p^s-{\gamma}{\rangle}}$ is a chain ring with maximal ideal ${\langle}x^2-{\delta}{\rangle}$, where ${\delta}p^s={\xi}_0$, and the number of codewords of ${\gamma}$-constacyclic code are provided. Furthermore, the self-orthogonal and self-dual ${\gamma}$-constacyclic codes of length $2p^s$ over $GR(p^a,m)$ are also established. Finally, we determine the Rosenbloom-Tsfasman (RT) distances and weight distributions of all such codes.

• Bulletin of the Korean Mathematical Society
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• v.60 no.5
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• pp.1281-1293
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• 2023

The purpose of this paper is to study the relationship between the structure of a factor ring R/P and the behavior of some derivations of R. More precisely, we establish a connection between the commutativity of R/P and derivations of R satisfying specific identities involving the prime ideal P. Moreover, we provide an example to show that our results cannot be extended to semi-prime ideals.

• Bulletin of the Korean Mathematical Society
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• v.47 no.5
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• pp.907-913
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• 2010

Let D be an integrally closed domain with quotient field K, * be a star operation on D, X, Y be indeterminates over D, $N_*\;=\;\{f\;{\in}\;D[X]|\;(c_D(f))^*\;=\;D\}$ and $R\;=\;D[X]_{N_*}$. Let b be the b-operation on R, and let $*_c$ be the star operation on D defined by $I^{*_c}\;=\;(ID[X]_{N_*})^b\;{\cap}\;K$. Finally, let Kr(R, b) (resp., Kr(D, $*_c$)) be the Kronecker function ring of R (resp., D) with respect to Y (resp., X, Y). In this paper, we show that Kr(R, b) $\subseteq$ Kr(D, $*_c$) and Kr(R, b) is a kfr with respect to K(Y) and X in the notion of [2]. We also prove that Kr(R, b) = Kr(D, $*_c$) if and only if D is a $P{\ast}MD$. As a corollary, we have that if D is not a $P{\ast}MD$, then Kr(R, b) is an example of a kfr with respect to K(Y) and X but not a Kronecker function ring with respect to K(Y) and X.