• Korean Journal of Applied Biomechanics
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• v.25 no.1
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• pp.57-64
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• 2015

Purpose : The purpose of this study was to analyze setter toss motion kinematically according to toss types. Method : Dependent variables were elapsed time, vertical displacement of the body center, the projected speed of the ball, and differences of the joint angle to the target for four setters positioning. Result : There was no significant difference in the time but the ball contact time was shorter when the toss distance of P3 was longer. There was significant difference in the vertical displacement of COM (p<.05). The vertical displacement of COM showed that the vertical movement gradually decreased when the quick distance was longer. The vertical displacement of COM was difference (p<.05), also there was difference of the ball speed (p<.001) at the Release point(E4). There was significant difference in the knee joint angle at a certain moment among the Release(E4) and Landing point(E5)(p<.05). The hip joint was significant difference among the Apex(E2), Ball Touch(E3), Release(E4), and the Landing point(E5) on the surface(E2, E3, E4 p<.05; E5 p<.005). The shoulder angle was significant difference among the Ball Touch(E3), Release(E4) and the Landing point(E5) on the surface(E3, E4 p<.05; E5 p<.001). The elbow was significant difference in the Apex(E2) (p<.05). The wrist was significant difference in the Release(E4) (p<.05). Conclusion : If we find the clue to expect the direction of the setter's ball, we have to fine the clues in the Apex(E2) that hip join and elbow, Ball Touch(E3) that hip joint and shoulder joint, Release(E4) that wrist, elbow, hip joint, and knee joint.

• Journal of applied mathematics & informatics
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• v.18 no.1_2
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• pp.497-503
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• 2005

This paper presents characterizations on the independence of the exponential and Pareto distributions by record values. Let ${X_{n},\;n {\ge1}$ be a sequence of independent and identically distributed(i.i.d) random variables with a continuous cumulative distribution function(cdf) F(x) and probability density function(pdf) f(x). $Let{\;}Y_{n} = max{X_1, X_2, \ldots, X_n}$ for n \ge 1. We say $X_{j}$ is an upper record value of ${X_{n},{\;}n\ge 1}, if Y_{j} > Y_{j-1}, j > 1$. The indices at which the upper record values occur are given by the record times {u(n)}, n \ge 1, where u(n) = $min{j|j > u(n-1), X_{j} > X_{u(n-1)}, n \ge 2}$ and u(l) = 1. Then F(x) = $1 - e^{-\frac{x}{a}}$, x > 0, ${\sigma} > 0$ if and only if $\frac {X_u(_n)}{X_u(_{n+1})} and X_u(_{n+1}), n \ge 1$, are independent. Also F(x) = $1 - x^{-\theta}, x > 1, {\theta} > 0$ if and only if $\frac {X_u(_{n+1})}{X_u(_n)}{\;}and{\;} X_{u(n)},{\;} n {\ge} 1$, are independent.

• Journal of applied mathematics & informatics
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• v.38 no.1_2
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• pp.189-200
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• 2020

Let G be a simple connected graph with n vertices and m edges. Denote by d₁ ≥ d₂ ≥ ⋯ ≥ d_n > 0 and d(e₁) ≥ d(e₂) ≥ ⋯ ≥ d(e_m) sequences of vertex and edge degrees, respectively. If vertices v_i and v_j are adjacent, we write i ~ j. The general sum-connectivity index is defined as 𝒳_α(G) = ∑_i~j(d_i + d_j)^α, where α is an arbitrary real number. Firstly, we determine a relation between 𝒳_α(G) and 𝒳_α-1(G). Then we use it to obtain some new bounds for 𝒳_α(G).

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.4
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• pp.373-378
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• 2012

The objective of this research is to examine the probabilistic approach to evaluating turbine ejection frequency considering common-cause failure. This paper identifies basic turbine ejection mechanisms under high and low speeds and presents a detailed probabilistic methodology (fault tree) for assessing ejection frequency. The alpha factor methodology is applied to common-cause failure evaluations. The frequencies under different test schemes are compared and the propagation of uncertainty through the fault tree model is evaluated. The following conclusions were reached: (1) the turbine blade ejection frequency due to ductile failure under high speed is around 8.005E-7/yr; (2) if common-cause failure is considered, the frequency will be increased by 11% and 33% depending on the test scheme; and (3) if the parameter uncertainties are considered, the frequency is estimated to be in the range of 9.35E-7 to 1.13E 6, with 90% confidence.

• Journal of the Korean Chemical Society
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• v.41 no.3
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• pp.117-122
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• 1997

On the basis of our previous paper[Bull. Korean Chem. Soc. 1995, 16, 1015], the relative stability, ionization potential, and chemical reaction of the neutral and multiply charged $C_{60}$n ions(n=3+ to 6-) have been investigated by the semi-empirical MNDO method. $C_{60}^{1-}$ has the highest stability. The ionization potential values of the $C_{60}$ ions range from 15.31 eV of $C_{60}^{2+}$ to -13.01 eV of $C_{60}^{6-}$. These values show a linear relationship according to charges. The average IP per charge is 3.15 eV from our calculations and 3.22 eV from the linear function of IP. A charge- or electron-transfer reaction of $C_{60}^{n+}$ will only occur if the ionization potential of any guest molecule is lower than the electron affinity of the host $C_{60}^{n+}$. If the energy gap between ionization potential and electron affinity, ${\Delta}_{IP-EA}$, is high, charge-transfer reactions arise by the charge-controlled effect. However, if ${\Delta}_{IP-EA}$ is low, electron-transfer reactions arise by the frontier-controlled effect.

• Journal of the Korea institute for structural maintenance and inspection
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• v.3 no.1
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• pp.171-178
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• 1999

Despite of decrease in shear and moment strengths, most steel structural designers use web openings in beams because of economical benefit and requirement. The purpose of this study is to suggest the method of reinforcement of H-shape steel beams with a rectangular web opening. If shear predominates over bending, it is necessary to consider all possible combinations of shear force and bending moment acting at the opening. In this paper, the ultimate strength and behavior of perforated beams have been investigated according to parameters (ratio of M/V, opening width within opening height ratio D/h, various reinforcing types A/B/C/D/M/N/W). The results of this study are as follows ; 1. Deformation of H-shape steel beams with a rectangular web opening was greatly affected by not only bending but also shear. 2. SB1-2/3 series have little difference in the reinforced efficiency, but SB1-2E/3E series have difference in the reinforced efficiency according to the reinforcement type. 3. Efficiency of SB1-2E/3E series is determined by reinforcing types, which RB1-2E-B/M/C and RB1-3E-M/D/C specimens have good efficient. Reinforcing type of perforated beams chooses efficient method according to ratio of M/V and D/h.

• Journal of Korea Multimedia Society
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• v.20 no.2
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• pp.313-321
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• 2017

The emergence of E-book have allowed readers to interact with other readers and to actively participate (e.g. social reading). Furthermore, there is a growing demand in writer's community to take the advantage of the feedback from their readers to update the content of E-book. To do that, they require the service that utilizes the user feedback while creating or updating the e-book content. This study aims to let authors collect and to apply the reader's feedback on E-book content. However, in order to apply the user feedback, users first need to explicitly type the feedback, and even if they do, authors need to develop the software to automatically analyze and to apply the user feedback. This makes difficult for authors without programming background to produce E-book with automatic content adaptation. In this paper, we propose Feedback Clue Model to generate, analyze and apply the user feedback into E-book content. Based on this model, we develop the block editor which allows easy implementation of E-book that can be dynamically updated.

• Bulletin of the Korean Mathematical Society
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• v.31 no.2
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• pp.187-192
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• 1994

The author extended the small properties of topological semilattices to that of regular semigroups [3]. In this paper, it could be shown that a semigroup S is almost regular if and only if over bar RL = over bar R.cap.L for every right ideal R and every left ideal L of S. Moreover, it has shown that the Bohr compactification of an almost regular semigroup is regular. Throughout, a semigroup will mean a topological semigroup which is a Hausdorff space together with a continuous associative multiplication. For a semigroup S, we denote E(S) by the set of all idempotents of S. An element x of a semigroup S is called regular if and only if x .mem. xSx. A semigroup S is termed regular if every element of S is regular. If x .mem. S is regular, then there exists an element y .mem S such that x xyx and y = yxy (y is called an inverse of x) If y is an inverse of x, then xy and yx are both idempotents but are not always equal. A semigroup S is termed recurrent( or almost pointwise periodic) at x .mem. S if and only if for any open set U about x, there is an integer p > 1 such that x$^{p}$ .mem.U.S is said to be recurrent (or almost periodic) if and only if S is recurrent at every x .mem. S. It is known that if x .mem. S is recurrent and .GAMMA.(x)=over bar {x,x$^{2}$,..,} is compact, then .GAMMA.(x) is a subgroup of S and hence x is a regular element of S.

• Honam Mathematical Journal
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• v.28 no.2
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• pp.197-204
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• 2006

For the evaluation algebra $F[e^{{\pm}{\chi}}]_M$, if M={$\partial$}, the automorphism group $Aut_{non}$($F[e^{{\pm}{\chi}}]_M$) and $Der_{non}$($F[e^{{\pm}{\chi}}]_M$) of the evaluation algebra $F[e^{{\pm}{\chi}}]_M$ are found in the paper [12]. For M={${\partial}^n$}, we find $Aut_{non}$($F[e^{{\pm}{\chi}}]_M$) and $Der_{non}$($F[e^{{\pm}{\chi}}]_M$) of the evaluation algebra $F[e^{{\pm}{\chi}}]_M$ in this paper. We show that a derivation of some non-associative algebra is not inner.

• Journal of the Korean Society of Clothing and Textiles
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• v.27 no.7
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• pp.809-818
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• 2003

The purpose of this study was to identify importance of gender in dynamic relationship structure in fashion internet shopping mall and to provide marketers e-CRM marketing strategy. Out of 473 customers, 470 who had purchased fashion products in fashion Internet shopping mall were surveyed for this study. The data was analyzed by factor analysis, 1-test, correlation analysis, Structural Equation Model(SEM) using AMOS program. As the results, both men and women had ‘relationship maintenance intention’ in e-CRM. However, only women had ‘intention to discontinue relationship’, when shopping mall made mistakes to them. Also, in men's group, ‘service’ only had effect on ‘Trust’, while ‘service’and ‘financial benefit’ had effects on‘Trust’ in women's group. If women would be dissatisfied with a shopping mall, they have a strong intention to disconnect with it. Based on these results, it could be concluded that men have more tolerance for shopping mall's mistakes than women have. Therefore, the results of this study provide e-CRM marketing strategy for fashion internet marketers.