• Korean Journal of Mathematics
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• 제25권3호
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• pp.389-403
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• 2017

The purpose of the present paper is to introduce and study new subclasses of analytic functions which generalize the classes of Janowski functions with respect to k-symmetric points. We also study certain interesting properties like covering theorem, convolution condition, neighborhood results and argument theorem.

• 호남수학학술지
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• 제43권3호
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• pp.417-431
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• 2021

In this study, we introduced the notions of rough statistical convergence and defined the set of rough statistical limit points of a sequence and obtained statistical convergence criteria associated with this set in 2-normed space. Then, we proved that this set is closed and convex in 2-normed space. Also, we examined the relations between the set of statistical cluster points and the set of rough statistical limit points of a sequence in 2-normed space.

• Restorative Dentistry and Endodontics
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• 제20권2호
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• pp.768-779
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• 1995

This study was performed to investigate the effect of root canal shaping techniques on the change of the shape of prepared root canal. 40 mesiobuccal canals of recently extracted mandibular 1st and 2nd molars were divided into 4 groups and shaped by step-down/balanced force technique, step-down/step-back technique, step-back technique and conventional technique respectively. The change of the shape of root canal was traced by superimposing the radiographs obtained before and after shaping of each root canal. The results were as follows. 1. By the experimented techniques except conventional technique, the root canals were more shaped in convex side of apical area and in concave side of most curved and coronal area than in the other sides(P<0.05). By conventional technique, the root canals were more shaped in convex side than in convave side from apex to orifice(P<0.05). 2. By step-down/balanced force technique, the cancave sides at C and D points of proximal view and C point of clinical view were more shaped than the convex side(P<0.05). Through the entire canal, the concave side was more shaped than the convex side in proximal view(P<0.01). But there was no statistical difference between both sides in clinical view. 3. By step-down/step-back technique, the change of root canal shape was not statistically different in concave and convex sides at each point of both views(P>0.05). And through the entire canal in proximal view, there was no statistical difference in shaping percentage between both sides. But through the entire canal in clinical view, the concave side was more shaped than the convex side(P<0.1). 4. By step-back technique, the convex side at B point of clinical more shaped than the other sides(P<0.05). Through the entire canal in proximal and clinical views, there was no statistical difference in shaping percentage between both sides. 5. Comparing the total shaping percentage among techniques, that in conventional technique was the greatest numerically, and followed by the percentages in step-down/step-back, step-down/balanced force and step-back technique. But, in proximal view, shaping percentages were not statistically different among techniques(P>0.05, ANOVA test). In clinical view, shaping percentages in step-back and conventional techniques were statistically different(P<0.01, ANOVA test). * Proximal view: radiograph taken in mesiodistal direction. * Clincal view: radiograph taken in faciolingual direction. A point : 1mm point from radiographic apex B point : center point between A and C points C point : most curved point of root canal D point : center point between C point and canal oriffice.

• 융복합기술연구소 논문집
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• 제10권1호
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• pp.7-12
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• 2020

We describe a efficient surface reconstruction method that reconstructs a 3D manifold polygonal mesh approximately passing through a set of 3D oriented points. Our algorithm includes 3D convex hull, octree data structure, signed distance function (SDF), and marching cubes. The 3D convex hull provides us with a fast computation of SDF, octree structure allows us to compute a minimal distance for SDF, and marching cubes lead to iso-surface generation with SDF. Our approach gives us flexibility in the choice of the resolution of the reconstructed surface, and it also enables to use on low-level PCs with minimal peak memory usage. Experimenting with publicly available scan data shows that we can reconstruct a polygonal mesh from point cloud of sizes varying from 10,000 ~ 1,000,000 in about 1~60 seconds.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제9권1호
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• pp.1-7
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• 2002

For A bounded subset G of a metric Space (X,d) and $\chi \in X$, let $f_{G}$ be the real-valued function on X defined by $f_{G}$($\chi$)=sup{$d (\chi, g)\in:G$}, and $F(G,\chi)$={$z \in X:sup_{g \in G}d(g,z)=sup_{g \in G}d(g,\chi)+d(\chi,z)$}. In this paper we discuss some properties of the map $f_G$ and of the set $ F(G, \chi)$ in convex metric spaces. A sufficient condition for an element of a convex metric space X to lie in $ F(G, \chi)$ is also given in this pope.

• Korean Journal of Mathematics
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• 제8권2호
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• pp.121-126
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• 2000

B.Djafari Rouhani and W.A.Kirk [3] proved the following theorem: Let Xbe a reflexive Banach space and $(x_n)_{n{\geq}0}$ be a nonexpansive (resp., firmly nonexpansive )sequence in X. Then the set of weak ${\omega}$-limit points of the sequence $(\frac{x_n}{n})_{n{\geq}1}$(resp., $(x_{n+1}-x_n)_{n{\geq}0$) always lies on a convex subset of a sphere centered at the origin of radius $d={\lim}_{n{\rightarrow}{\infty}}\frac{{\parallel}x_n{\parallel}}{n}$. In this paper we show that the above theorem for nonexpansive(resp., firmly nonexpansive) sequences holds in a general Banach space(resp., a strictly convex dual $X^*$).

• Korean Journal of Mathematics
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• 제19권1호
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• pp.1-16
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• 2011

In this paper, using differential operator, we have introduce new class of p-valent uniformly convex functions in the unit disc U = {z : |z| < 1} and obtain the coefficient bounds, extreme bounds and radius of starlikeness for the functions belonging to this generalized class. Furthermore, partial sums $f_k(z)$ of functions $f(z)$ in the class $S^*({\lambda},{\alpha},{\beta})$ are considered. The various results obtained in this paper are sharp.

• 대한수학회논문집
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• 제12권2호
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• pp.275-285
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• 1997

Let E be a uniformly convex Banach space with a uniformly G$\hat{a}teaux differentiable norm, C a nonempty closed convex subset of $E, T : C \to E$ a nonexpansive mapping, and Q a sunny nonexpansive retraction of E onto C. For $u \in C$ and $t \in (0,1)$, let $x_t$ be a unique fixed point of a contraction $R_t : C \to C$, defined by $R_tx = Q(tTx + (1-t)u), x \in C$. It is proved that if ${x_t}$ is bounded, then the strong $lim_{t\to1}x_t$ exists and belongs to the fixed point set of T. Furthermore, the strong convergence of ${x_t}$ in a reflexive and strictly convex Banach space with a uniformly G$\hat{a}$teaux differentiable norm is also given in case that the fixed point set of T is nonempty.

• 대한기계학회논문집
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• 제12권4호
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• pp.916-925
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• 1988

본 연구에서는 이에 대한 현상을 이해하기 위한 노력의 일환으로 반원호가 유 동방향에 오목하게 놓여있는 경우와 볼록하게 놓여있는 두 특수한 경우에 대해 Re수를 0.1부터 50까지 증가시켜가며 수치해를 구하여 박리점, 와류길이, 그리고 와도와 유선 들을 중점적으로 조사하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.909-912
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• 2006

This paper examined the applicability of convex hull, which is defined as the minimal convex polygon including all points, to assessment model for effective region. In order to validate the applicability of the convex hull to assessment model for effective region, a genetic algorithm was adopted as a optimum technique, and an artificial neural network was adopted as a prediction model for material properties. The mix-proportion obtained from the proposed technique is more reasonable than that obtained from previous work.