• Honam Mathematical Journal
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• v.36 no.4
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• pp.913-919
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• 2014

We investigate the relationships between the space X and the hyperspaces concerning admissibility and connectedness im kleinen. The following results are obtained: Let X be a Hausdorff continuum, and let A, $B{\in}C(X)$ with $A{\subset}B$. (1) If X is c.i.k. at A, then X is c.i.k. at B if and only if B is admissible. (2) If A is admissible and C(X) is c.i.k. at A, then for each open set U containing A there is a continuum K and a neighborhood V of A such that $V{\subset}IntK{\subset}K{\subset}U$. (3) If for each open subset U of X containing A, there is a continuum B in C(X) such that $A{\subset}B{\subset}U$ and X is c.i.k. at B, then X is c.i.k. at A. (4) If X is not c.i.k. at a point x of X, then there is an open set U containing x and there is a sequence $\{S_i\}^{\infty}_{i=1}$ of components of $\bar{U}$ such that $S_i{\longrightarrow}S$ where S is a nondegenerate continuum containing the point x and $S_i{\cap}S={\emptyset}$ for each i = 1, 2, ${\cdots}$.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.6
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• pp.819-828
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• 2001

The operating point of a small-sized axial fan is strongly dependent upon the system resistance. Therefore, the turbulent flow characteristics around a small-sized axial fan may change significantly according to the operating point. This study represents three-dimensional turbulent flow characteristics around a small-sized axial fan measured at the ideal design point $\phi$=0.25, which is equivalent to the maximum total efficiency point, by using three dimensional fiber-optic type LDA system. This LDA system is composed of a 5 W Argon-ion laser, two optics in back-scatter mode, three BSAs, a PC, and a three-dimensional automatic traversing system. A kind of paraffin fluid is used to supply particles by means of fog generator. Mean velocity profiles downstream of a small-sized axial fan along the radial distance show that the streamwise and the tangential components exist in a predominant manner, while the radial component has a small scale distribution and shows the inflection which its flow direction is inward or outward. Moreover, the turbulent intensity profiles show that the radial component exists the most greatly among turbulent energies.

• Journal of Computational Design and Engineering
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• v.3 no.1
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• pp.14-23
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• 2016

The problem of fitting B-spline curves to planar point clouds is studied in this paper. A novel method is proposed to deal with the most challenging case where multiple intersecting curves or curves with self-intersection are necessary for shape representation. A method based on Delauney Triangulation of data points is developed to identify connected components which is also capable of removing outliers. A skeleton representation is utilized to represent the topological structure which is further used to create a weighted graph for deciding the merging of curve segments. Different to existing approaches which utilize local shape information near intersections, our method considers shape characteristics of curve segments in a larger scope and is thus capable of giving more satisfactory results. By fitting each group of data points with a B-spline curve, we solve the problems of curve structure reconstruction from point clouds, as well as the vectorization of simple line drawing images by drawing lines reconstruction.

• Archives of Plastic Surgery
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• v.42 no.4
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• pp.419-423
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• 2015

Background Orthognathic surgery is required in 25% to 35% of patients with a cleft lip and palate, for whom functional recovery and aesthetic improvement after surgery are important. The aim of this study was to examine maxillary and mandibular changes, along with concomitant soft tissue changes, in cleft patients who underwent LeFort I osteotomy and sagittal split ramus osteotomy (two-jaw surgery). Methods Twenty-eight cleft patients who underwent two-jaw surgery between August 2008 and November 2013 were included. Cephalometric analysis was conducted before and after surgery. Preoperative and postoperative measurements of the bone and soft tissue were compared. Results The mean horizontal advancement of the maxilla (point A) was 6.12 mm, while that of the mandible (point B) was -5.19 mm. The mean point A-nasion-point B angle was $-4.1^{\circ}$ before surgery, and increased to $2.5^{\circ}$ after surgery. The mean nasolabial angle was $72.7^{\circ}$ before surgery, and increased to $88.7^{\circ}$ after surgery. The mean minimal distance between Rickett's E-line and the upper lip was 6.52 mm before surgery and 1.81 mm after surgery. The ratio of soft tissue change to bone change was 0.55 between point A and point A' and 0.93 between point B and point B'. Conclusions Patients with cleft lip and palate who underwent two-jaw surgery showed optimal soft tissue changes. The position of the soft tissue (point A') was shifted by a distance equal to 55% of the change in the maxillary bone. Therefore, bone surgery without soft tissue correction can achieve good aesthetic results.

• Journal of applied mathematics & informatics
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• v.41 no.4
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• pp.883-892
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• 2023

In this research, under some specific situations, we precisely derive new coupled fixed point theorems in a complete b-metric space endowed with the graph. We also use the concept of coupled fixed points to ensure the solution of differential equations for the system of impulse effects.

• The Pure and Applied Mathematics
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• v.4 no.1
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• pp.19-26
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• 1997

In this paper, we characterize the existence of fixed points of a multivalued function by the existence of complete preorder on the given domain. Also we investigate relations between the completeness of a given order and the fixed point property of some multivalued functions.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.4
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• pp.429-435
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• 1998

Experiments were conducted to investigate the turbulent flow characteristics from on oblique impingement surface to an plane jet at the jet Reynolds number(Re based on the nozzle width) $3{\times}10^4$ The jet mean velocity and turbulent intensity profiles have been measured along the impingement surface by hot-wire anemometer. The nozzle-to-plate distance(H/B) ranged from 2 to 10 and the oblique angle (a) from 45 to 90 degree. Also the secondary peak of the turbulent intensity was observed at H/B=4 S/B 5 and a=90 degree. It has been found that the stagnation point shifted toward the minor flow region as the oblique angle decreased and the position of the stagnation point nearly coincided with that of the maximum turbulent intensity.

• Bulletin of the Korean Mathematical Society
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• v.26 no.1
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• pp.43-46
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• 1989

In this paper, we are concerned with the pointwise-hypoellipticity (see Definition 2.1) of an m-dimensional Frobenious Lie algebra L of analytic complex vector fields in somel open subset .ohm. of $R^{m+1}$. That is, L is a set of complex vector fields in .ohm. with (real-) analytic coefficients satisfying: (A) each point of .ohm. has an open neighborhood in which L is generated by m linearly independent elements of L; (B) L is closed under the commutation bracket [A, B]. The pointwise-analytic hypoellipticity of L is completely characterized by M.S. Baouendi and F. Treves in [1]. Here, we shall prove that if L is hypoelliptic at a point then it must be analytic hypoelliptic in a full neighborhood of the same point. When the coefficients are $C^{\infty}$, hypoellipticity of L was discussed in [2].2].

• Korean Journal of Computational Design and Engineering
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• v.3 no.2
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• pp.87-102
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• 1998

Given a sequence of cross-sectional curves, the skinning method generates a freeform surface that interpolates the given curves in that sequence. This thesis presents a construction method of a B-spline skinning surface that is fair and satisfies volume constraints. The fairness metric is based on the parametric energy functional of a surface. The degrees of freedom in surface control are closely related lo control points in the skinning direction. The algorithm fur finding a skinning surface consists of two step. In the first step, an initial fair surface is generated without volume constraints and one coordinate of each control point is fixed. In the second step, a final surface that meets all constraints is constucted by rearranging the other coordinates of each control point that defines the initial surface A variational Lagrange optimization method produces a system of nonlinear equations, which can be solved numerically. Moreover, the reparametrization of given sectional curves is important for the construction of a reasonable skinning surface. This thesis also presents an intuitive metric for reparametrization and gives some examples that are optimized with respect to that metric.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.11
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• pp.1426-1433
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• 1999

Topological and kinematical studies of the singular points found in flows around a surface-mounted cube in a channel are presented. Numerical simulation was carried out using high-resolution grid systems. Singular points(saddles and nodes) were found around the cube, which satisfy the topological rules suggested by Hunt et al. As the Reynolds number increases, the structure of vortices around the cube becomes complex and the number of singular points increases. Nevertheless, the rule governing the numbers of singular points is still valid. This confirms that our simulation is correct from topological and kinematical point of view, and enables one to infer complex flow patterns in our simulation.