• Journal of the Korean Mathematical Society
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• v.39 no.1
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• pp.77-89
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• 2002

In this paper, we define for a component $X_{0}$ of a nonsingular compact real algebraic surface X the complex genus of $X_{0}$, denoted by gc($X_{0}$), and use this to prove the nonexistence of nonzero degree entire rational maps f : $X_{0}$ Y provided that gc(Y) > gc($X_{0}$), analogously to the topological category. We construct connected real surfaces of arbitrary topological genus with zero complex genus.

• Journal of the Korean Mathematical Society
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• v.46 no.1
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• pp.31-39
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• 2009

A bifurcation problem for nonlinear partial differential equations of the form $$div({\varphi}(|{\nabla}u|){\nabla}u+{\mu}_0{\varphi}(|u|)u=q({\lambda},\;x,\;u,\;{\nabla}u)$$ subject to Dirichlet boundary conditions is discussed. Using a global bifurcation theorem of Rabinowitz type, we show that under certain conditions on $\varphi$ and q, the above equation has an unbounded connected set of solutions (u, $\lambda$).

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.07a
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• pp.286-289
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• 2012

본 논문은 3차원 깊이 정보를 이용하여 감시카메라에서 움직이는 사람을 검출하고 추적하는 방법을 제안한다. 제안하는 방법은 GMM(Gaussian mixture model)을 이용하여 배경과 움직이는 사람을 분리한 후, 분리된 영역을 CCL(connected-component labeling)을 통하여 각각 블랍(blob) 단위로 나누고 그 블랍을 추적한다. 그 중 블랍 단위로 나누는 데 있어 두 블랍이 합쳐진 경우, 3차원 깊이 정보를 이용하여 두 블랍을 분리하는 방법을 제안한다. 실험을 통하여 제안하는 방법의 결과를 보인다.

• International Journal of Reliability and Applications
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• v.9 no.1
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• pp.79-93
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• 2008

The aim of this work is to generalize reliability equivalence techniques to apply them to a system consists of two independent and non-identical components connected in series(parallel) system, that have constant failure rates. We shall improve the system by using one component only. We start by establishing two different types of reliability equivalence factors, the survival reliability equivalence (SRE) and mean reliability equivalence (MRE) factors. Our second studies, introducing some applications for our studies in airports and our life. Also, we introduced some numerical results.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.5
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• pp.770-778
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• 1994

In this paper, the photovoltaic inverter system with instantaneous sinusoidal current tracking control is proposed to improve the utilization factor of photovoltaic power system which would be connected utility interactive system. The proposed inverter is designed to track maximum power point by two-state value control method and utility interactive operation, and to decrease output harmonics component. Optimal operating region is described by state space averaging method, and present tracking condition of standard guide line. The experimental result shows the effectiveness of inverter system using the instantaneous control method.

• Proceedings of the KIEE Conference
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• 1985.07a
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• pp.26-28
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• 1985

The open delta circuit of the power transformer is still often applied, in spite of its reduced utilization of the power. In this paper, a new approach to the calculation of the power and its distribution in each transformer component is presented. For the power evaluation, the method of the complex power analysis is applied.

• Bulletin of the Korean Mathematical Society
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• v.58 no.6
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• pp.1495-1506
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• 2021

The growth of solutions of second order complex differential equations f" + A(z)f' + B(z)f = 0 with transcendental entire coefficients is considered. Assuming that A(z) has a finite deficient value and that B(z) has either Fabry gaps or a multiply connected Fatou component, it follows that all solutions are of infinite order of growth.

• The KIPS Transactions:PartD
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• v.18D no.6
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• pp.501-508
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• 2011

A knowledge map, which has been recently applied in various fields, is discovering characteristics hidden in a large amount of information and showing a tangible output to understand the meaning of the discovery. In this paper, we suggested a knowledge map for research trend analysis based on keyword-relation networks which are constructed by using a database of the domestic journal articles in the computer engineering field from 2000 through 2010. From that knowledge map, we could infer influential changes of a research topic related a specific keyword through examining the change of sizes of the connected components to which the keyword belongs in the keyword-relation networks. In addition, we observed that the size of the largest connected component in the keyword-relation networks is relatively small and groups of high-similarity keyword pairs are clustered in them by comparison with the random networks. This implies that the research field corresponding to the largest connected component is not so huge and many small-scale topics included in it are highly clustered and loosely-connected to each other. our proposed knowledge map can be considered as a approach for the research trend analysis while it is impossible to obtain those results by conventional approaches such as analyzing the frequency of an individual keyword.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.4
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• pp.439-446
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• 2014

This study introduces about the analysis, verification and implementation of Digital Communication Satellite transponder. Through the pre-performance analysis of each component by the circuit level simulation, each component's performance was checked whether satisfying the specifications. When each of the components was connected in order, System's performances were evaluated through system harmonic balanced simulation whether satisfying the specifications. Through pre-analysis of the system performance, specification of each component was defined. On the basis of that specification, Components which comprise the Digital Communication Satellite repeater were manufactured, and finally, the overall system performance check was made by integrating the components of Digital Communication Satellite transponder.

• Korean Journal of Computational Design and Engineering
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• v.2 no.1
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• pp.53-59
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• 1997

Current CAD systems used in the AEC community have some critical problems. One of them is that they hardly support design collaboration. Thus designers and engineers are hard to transfer design knowledge from one discipline to another. What we need is a common building database which creates and manages building plans/models and relevant design knowledge consistently and effectively. This paper presents a powerful CAD editor, called UNIFORM, which is being developed. Currently UNIFORM includes three main modules: a plan generator, a 3-D model generator, and component databases. A plan generator, called UNIFORM PLANNER, creates a plan which contains semantically-rich information of building. Each component in the plan can be presented in various ways and connected to component databases that contain knowledge of building components such as windows, doors, walls, etc. Based on the plan UNIFORM MODELER, another module of the program, generates a three dimensional building model which could be a multiple-story building. One of the main ideas behind the system is that it generates and maintains a common building form that can be easily delivered to other members of the project team. Thus it is expected to increase system integration, team interactions, and productivity.