• 대한소아치과학회지
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• 제21권2호
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• pp.570-576
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• 1994

Ectodermal dysplasia is characterized by a partial or complete lack of primary and permanent teeth, other ectodermal structures that may be affected include the skin, hair, and sweat glands. The patient with the so-called anhidrotic type of ectodermal dysplasia exhibits dry skin, lack of sweat glands, sparse eyebrows, body hair, saddle nose, and everted lips. Genetic basis of anhidrotic ectodermal dysplasia is recessive and sex-linked, being manifested chiefly in males, but this is debatable. A 6-year-old boy, with typical signs of anhidrotic ectodermal dysplasia, was presented. Prosthetic restoratoins are of great value to these patients, both from the standpoint of function and for psychologic reasons. The need for complete denture is critical during preschool periods and continues into adulthood. The following case report is an approach to the management of a patient with anhidrotic ectodermal dysplasia.

• 품질경영학회지
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• 제9권2호
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• pp.31-36
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• 1981

점증되고 있는 고신뢰성 제품의 설계에 있어 주어진 선형제약조건 내(內)에서 체계의 신뢰성을 최대화하는 방법을 소개하고 이를 해결하는 비선형계획법을 반복단계로 하여 Computer Programming을 하였다. 단, 본 논문에서 다루는 체계는 병렬중복구조를 갖는 직렬다단계 구조이다. 타당성 검토를 위한 예제를 해결하였으며 Computer Programming은 지면관계로 생략하였다.

• 대한기계학회논문집B
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• 제23권11호
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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.

• 대한기계학회논문집B
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• 제23권11호
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• pp.1418-1425
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• 1999

Flow over a protruding surface is investigated using numerical simulation. We consider flow between two parallel plates with a cube mounted on one side of the channel. As the flow approaches the cube, the adverse pressure gradient produces three-dimensional boundary-layer separation, resulting In the formation of horseshoe vortices. The objective of our study is to clarify both the steady and the unsteady characteristics of the vortex system. As the Reynolds number increases, the structure of the vortices near the cube becomes complex and the number of vortices increases. The distribution of skin friction on the cube-mounted wall reflects the effect of the horseshoe vortices. All these results are consistent with the experimental findings currently available.

• 대한수학회지
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• 제54권2호
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• pp.663-673
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• 2017

We consider the multi-harmonic model for the bubble evolution in the Rayleigh-Taylor instability in two and three dimensions. We extend the multi-harmonic model in two dimensions to a high-order and present a new class of steady-state solutions of the bubble motion. The growth rate of the bubble is expressed by a continuous family of two free parameters. The critical point in the family of solutions is identified as a saddle point and is chosen as the physically significant solution. We also present the multi-harmonic model in the cylindrical geometry and find the steady-state solution of the axisymmetric bubble. Validity and limitation of the model are also discussed.

• 로봇학회논문지
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• 제4권4호
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• pp.327-333
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• 2009

This paper describe the riding robot system named by "RideBot" which is a riding robot like as a horse. In order to simulate the riding motions, we develope the saddle mechanism which can generate 3 DOF motions including pitch, roll, and bounce movement, and also we controlled the riding motions and the intention of horseman. To generate the riding motions with the bodily sensation, we developed Novel Washout Filter and the algorithms for motion control. And also, we developed some health care service for the health care of horseman. A body state index was proposed that evaluates the personal health state from both the measured physiological variables and the surveyed questions. The physiological variables such as weight, blood pressure, heart rate variability (HRV), accelerated state photoplethysmograph(APG), body fat, and happiness index were measured by the specially designed bio-handle system and survey questions. The efficiency of the proposed ride robot is evaluated in the experiments.

• Korean Journal of Mathematics
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• 제6권1호
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• pp.27-46
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• 1998

We are concerned with an optimal control problem governed by a Poisson equation in which body force acts like a control parameter. The cost functional to be optimized is taken to represent the error from the desired observation and the cost due to the control. We recast the problem into the mixed formulation to take advantage of the minimax principle for the duality method. The existence of a saddle point for the Lagrangian shall be shown and the optimality system will be derived therein. Finally, to attain an optimal control, we combine the optimality system with an operational technique. By achieving the gradient of the cost functional, a convergent algorithm based on the projected gradient method is established.

• 대한수학회지
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• 제54권1호
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• pp.1-16
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• 2017

In this paper we study a four dimensional tourism-based social-ecological dynamical system. In fact we analyse tourism profitability, compatibility and sustainability by using bifurcation theory in terms of structural properties of attractors of system. For this purpose first we transformed it into a three dimensional system such that the reduced system is the extended and modified model of the previous three dimensional models suggested for tourism with the same dimension. Then we investigate transcritical, pitchfork and saddle-node bifurcation points of system. And numerically by finding some branches of stable equilibria for system show the profitability of tourism industry. Then by determining the Hopf bifurcation points of system we find a family of stable attractors for that by numerical techniques. Finally we conclude the existence of these stable limit cycles implies profitability and compatibility and then the sustainability of tourism.

• 한국통신학회논문지
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• 제22권2호
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• pp.298-305
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• 1997

In this paper, the radiation characteristics of a slot annenna in conduction cylinder covered with a moving isotropic plasma layer are analyzed. Integral representations of the eletromagnetic fields in the spectral domain radiated through the plasma layer are derived and converted into the fields in the spacial domain by saddle-point ingegration. Radiation null which brings about distorion in the radiation parrern is explained by the zero of integrand in an asymptotic integral as a function of plasma and velocity parameters. Numerical results for a radiation null calculated from various plasma and velocity parameters correspond to the results of planner structure.

• KIEE International Transactions on Power Engineering
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• 제4A권1호
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• pp.1-5
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• 2004

The model of a power system with load dynamics is studied by investigating qualitative changes in its behavior as the reactive power demand at a load bus is increased. The load is created using induction motors parallel with the constant power and constant impedance load. As the load increases, the system experiences various bifurcations such as sub critical and supercritical Hopf, period-doubling and saddle-node bifurcation. The latter may lead the system to voltage collapse. A nonlinear controller is used to control the subcritical Hopf bifurcation and hence mitigate voltage collapse. It is applied to the KEPCO (Korean Electric Power Company) system to demonstrate its validity.