• 대한수학회지
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• 제32권3호
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• pp.371-387
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• 1995

Let X be a compact polyhedron, H a normal subgroup of the fundamental group $\pi_1(X)$ of X and $f : X \longrightarrow X$ a selfmap such that $f_piH \subset H$, where f_\pi : \pi_1(X) \longrightarrow \pi_1(X)$ is the induced homomorphism by f.

• 한국광학회:학술대회논문집
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• 한국광학회 2006년도 동계학술발표회 논문집
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• pp.311-312
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• 2006

• PNF and Movement
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• 제7권3호
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• pp.7-16
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• 2009

The purpose of this study was to investigate the effects of plantar flexion exercise and stepper on the balance ability in normal peoples. Twenty subjects participated in this experiment were carried out the program on 6 weeks plantar flexion exercise and stepper. They were divided into two groups; plantar flexion group(plantar flexion exercise group, n=10) and stepper group(using stepper group, n=10). The effects of plantar flexion exercise and using stepper were evaluated by measurements of normal standing(NSEO, NSEC), and semitandom standing and dynamic type 1 and dynamic type 2, respectively. For each case, the experimental data were obtained about static balance in 3 items: mean X speed, mean Y speed and velocity moment, that of dynamic balance in 2 items: mean X speed, mean Y speed. The results of this study were as follows; 1. In plantar flexion exercise group, the statistically significants were shown on X, Y speed and velocity moment in the case of NSEO, NSEC, semitandom standing, and on X, Y speed in the case of dynamic type 1, dynamic type 2. 2. In using stepper group, the statistically significants were shown on X, Y speed and velocity moment in the case of NSEO, NSEC, semitandom and on only X, Y speed in the case of dynimic type 1, dynaimic type 2. 3. There was a statistically significant similar on all about case. however, the statistically difference were not shown with intergroup. The above results revealed that plantar flexion exercise and using stepper was effective for improving the balance ability.

• 한국식품영양과학회지
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• 제27권5호
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• pp.945-951
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• 1998

The purpose of this study was to investigate the effects of dietary xylooligosaccharide on lipid levels of serum in rats fed high cholesterol diet. Male Sprage-Dawley rats weiging 100$\pm$10g were randomly assigned to groups of two normal(N, N+10X) and four high cholesterol diets which contained 1%(w/w) cholesterol. High cholesterol diet groups were classified to xylooligosaccharide free diet (C group), 5% xylooligosaccharide diet(C+5X group), 10% xylooligosaccharide diet(C+10X group) and 15% xylooligosaccharide diet(C+15X group) according to the level of dietary xylooligosaccharide supplementation. These experimental diets were fed ad libidum for 4 weeks. The weight gain of high cholesterol diet group were significantly increased more than that of normal group, but those of 10% and 15% dietary xylooligosaccharide groups were significantly decreased more than that of high cholesterol diet(C)group. The higher content of xylooligosaccharide, the more food intake was increased. The food efficiencies of 10%, 15% cholesterol diet groups were lower than that of high cholesterol diet(C)group. The levels of serum triglyceride(TG) and total cholestoral were significantly high in cholesterol diet groups compared with normal diet group but were decreased in groups fed 5% and 10% dietary xylooligosaccharide. Especially, the lowest level showed in group fed high cholesterol diet containing 10% xylooligosacchride. High cholesterol diet group containing 10% xylooligosaccharide increased HDL-cholesterol level and then decreased LDL-cholesterol level and atherogenic index compared with other groups. The level of TBARS(thiobarbituric acid reactive substances) in serum was decreased in rat group fed xylooligosaccharide in high cholesterol diet. The higher content of xylooligosacchride, the more gastrointestinal transit time was decreased. The results indicate that dietary xylooligosaccharide can improve status of TG and total cholesterol and repress lipid peroxidation in serum lipid at hypercholesterolemia induced by high cholesterol diet.

• Journal of applied mathematics & informatics
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• 제29권5_6호
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• pp.1421-1433
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• 2011

In this paper, using a fixed point approach, the generalized Hyeres-Ulam stability of the following quadratic functional equation $f(x+y+z)+f(x+{\sigma}(y))+f(y+{\sigma}(z))+f(x+{\sigma}(z))=3(f(x)+f(y)+f(z))$ will be studied, where f is a function from abelian group G into a quasi-${\beta}$-normed space and ${\sigma}$ is an involution on the group G. Next, we consider its pexiderized equation of the form $f(x+y+z)+f(x+{\sigma}(y))+f(y+{\sigma}(z))+f(x+{\sigma}(z))=g(x)+g(y)+g(z)$ and its generalized Hyeres-Ulam stability.

• 대한수학회보
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• 제32권1호
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• pp.35-43
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• 1995

IF R is a left Artinian ring with identity, G is the group of units of R and X is the set of nonzero, nonunits of R, then G acts naturally on X by conjugation. It is shown that if the conjugate action on X by G is trivial, that is, gx = xg for all $g \in G$ and all $x \in X$, then R is a commutative ring. It is also shown that if the conjegate action on X by G is transitive, then R is a local ring and $J^2 = (0)$ where J is the Jacobson radical of R. In addition, if G is a simple group, then R is isomorphic to $Z_2 [x]/(x^2 + 1) or Z_4$.

• East Asian mathematical journal
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• 제33권3호
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• pp.257-263
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• 2017

Let n be any positive integer and ${\mathbb{Z}}_n=\{0,1,{\cdots},n-1\}$ be the ring of integers modulo n. Let $X_n$ be the set of all nonzero, nonunits of ${\mathbb{Z}}_n$, and $G_n$ be the group of all units of ${\mathbb{Z}}_n$. In this paper, by investigating the regular action on $X_n$ by $G_n$, the following are proved : (1) The number of orbits under the regular action (resp. the number of annihilators in $X_n$) is equal to the number of all divisors (${\neq}1$, n) of n; (2) For any positive integer n, ${\sum}_{g{\in}G_n}\;g{\equiv}0$ (mod n); (3) For any orbit o(x) ($x{\in}X_n$) with ${\mid}o(x){\mid}{\geq}2$, ${\sum}_{y{\in}o(x)}\;y{\equiv}0$ (mod n).

• 대한안전경영과학회지
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• 제6권3호
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• pp.87-97
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• 2004

The National Health Insurance Act, the Industrial Health Act and the School Health Act require chest radiography at least once a year. In chest radiographic examination, most group examinations use indirect X-ray primarily aiming at diagnosing diseases and enhancing people's health. This study purposed to minimize radiation exposure dose by comparing it between direct and indirect chest X-ray studies. According to the result of comparing and analyzing radiation exposure dose, the average incident dose and penetrating dose were 0.929μGy and 0.179μGy respectively in direct chest X-ray and 6.807μGy and 1.337μGy in indirect chest X-ray In order to minimize radiation exposure dose at direct and indirect chest X-ray, indirect X-ray should be excluded from group examination if possible. Moreover, it is necessary to control the quality of equipment (Q/A & Q/C) systematically and to avoid using unqualified equipment in order to reduce radiation exposure dose.

• 대한방사선기술학회지:방사선기술과학
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• 제40권1호
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• pp.63-70
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• 2017

본 연구는 세기변조방사선 치료기술을 이용한 성문암 환자에게 사용되는 두 가지 상이한 열가소성 고정기구 마스크로 인한 환자위치잡이 오차를 비교 평가하고 자 하였다. 치료가 종료된 총 16명의 성문암 환자를 두 그룹으로 나누었고(기존마스크 vs. 변형마스크), 평균, 3D오차, 시스템과 랜덤오차를 구하여 환자위치잡이 오차를 비교하였다. 또한, 치료계획종양체적(PTV)에 대한 여백(margin)을 분석하였다. 3D오차에 대하여 기존 그룹은 $5.2{\pm}1.3mm$고, 변형그룹은 $5.9{\pm}0.7mm$로써, 변형마스크가 변형보다 13.6% 높았다. 시스템오차는 기존그룹(변형그룹)에서 좌표 x, y, z방향은 각각 1.7 mm (1.1 mm), 1.0 mm (1.8 mm), 1.5 mm (2.0 mm)였고, 회전각(roll angle)은 $0.8^{\circ}$ ($0.8^{\circ}$)였다. 랜덤오차는 변형그룹이 기존그룹에 비하여 좌표 x, y, z방향으로 10.9%, 1.7%, 23.1%로 낮았으나, 회전각은 12.4% 높았다. PTV여백에서 변형그룹은 좌표 x방향에 대하여 기존그룹에 비하여 31.8% 낮았으나, 반대로 좌표 y와 z방향에서는 기존그룹보다 각각 52.6%와 21.6%로 높았다. 성문암 세기변조방사선치료에서 변형된 마스크 사용은 고정기구의 변형으로 인한 환자위치잡이 오차는 수치적으로는 영향을 줄 수 있지만, 다양한 관점에서 고정기구 마스크에 대한 연구가 임상적인 측면에서 연구가 필요할 것으로 사료된다.

• 대한수학회지
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• 제59권3호
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• pp.571-594
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• 2022

Let D be an integral domain with quotient field K, Pic(D) be the ideal class group of D, and X be an indeterminate. A polynomial overring of D means a subring of K[X] containing D[X]. In this paper, we study almost Dedekind domains which are polynomial overrings of a principal ideal domain D, defined by the intersection of K[X] and rank-one discrete valuation rings with quotient field K(X), and their ideal class groups. Next, let ℤ be the ring of integers, ℚ be the field of rational numbers, and 𝔊f be the set of finitely generated abelian groups (up to isomorphism). As an application, among other things, we show that there exists an overring R of ℤ[X] such that (i) R is a Bezout domain, (ii) R∩ℚ[X] is an almost Dedekind domain, (iii) Pic(R∩ℚ[X]) = $\oplus_{G{\in}G_{f}}$ G, (iv) for each G ∈ 𝔊f, there is a multiplicative subset S of ℤ such that RS ∩ ℚ[X] is a Dedekind domain with Pic(RS ∩ ℚ[X]) = G, and (v) every invertible integral ideal I of R ∩ ℚ[X] can be written uniquely as I = XnQe11···Qekk for some integer n ≥ 0, maximal ideals Qi of R∩ℚ[X], and integers ei ≠ 0. We also completely characterize the almost Dedekind polynomial overrings of ℤ containing Int(ℤ).