• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.06a
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• pp.101-103
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• 2013

최근 HD (High Definition) 또는 3D (Three Dimension) 이상의 고품질 방송 콘텐츠 수요가 증가하면서 디지털 방송 시스템은 실시간으로 실감형 서비스를 제공하기 위하여 발전 하였다. 특히, 세계 방송 비영리 협회 FoBTV (Future of Broadcast Television) 는 더 나아가 초 고해상도 UHD (Ultra High Definition) 급 이상의 영상을 제공하기 위해 지상파 방송과 유선 케이블 방송 시스템을 이용하여 고품질, 다시점 방송 서비스 뿐 아니라 낮은 전계 강도 환경에서 수신율을 높일 수 있는 기술방안을 논의하고 있다. 본 논문은 이와 같은 세계 방송 발전 흐름에 따라 지상파 및 케이블 방송 송수신 시스템을 구현하고 수신되는 영상의 품질을 평가하였다. 또한, 구현된 통합 시스템은 지상파로 수신되는 파일럿 신호의 크기를 분석하여 케이블로 재전송 되며 이를 통해 수신 성능의 품질을 향상시킨다.

• Korean Management Science Review
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• v.16 no.1
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• pp.137-156
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• 1999

Flexibility is a competitive weapon in the changing environment. In order to pursue the flexibility, Korean manufacturing companies must define the flexibility dimension clearly, build the appropriate manufacturing infrastructures and measure the right flexibility performance indicators. This paper found out as follows. First, Korean manufacturing companies' flexibility strategy groups were formed three types. They are flexibility superior group, middle flexibility group and flexibility inferior group. Second, when different types of flexibility strategy group measured their performances, the degree of importance of flexibility performance indicators were different among groups. Third, when different types of flexibility strategy group were pursued, the different manufacturing methods such as product/process design technology, analysis technology, production system management technology and non technological factors were used. Lastly, when different types of flexibility strategy group were pursued, the actual flexibility performances were different among groups.

• Communications of the Korean Mathematical Society
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• v.10 no.1
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• pp.39-48
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• 1995

The ADI method was introduced by Peaceman and Rachford [6] in 1955, to solve the discretized boundary value problems for elliptic and parabolic PDEs. The finite difference discretization of the model elliptic problem $$ (1) -\Delta u = f, \Omega = [0, 1] \times [0, 1] $$ $$ u = 0 on \delta \Omega $$ with 5-point centered finite difference discretization, with n +2 mesh-points in the x - direction and m + 2 points in the y direction, leads to the solution of a linear system of equations of the form $$ (2) Au = b $$ where A is a matrix of dimension $N = n \times m$. Without loss of generality and for the sake of simplicity, we will assume for the remainder of this paper that m = n, so that $N = n^2$.

• Bulletin of the Korean Mathematical Society
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• v.53 no.4
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• pp.1087-1094
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• 2016

On a compact n-dimensional manifold M, it has been conjectured that a critical point of the total scalar curvature, restricted to the space of metrics with constant scalar curvature of unit volume, is Einstein. In this paper, after derivng an interesting curvature identity, we show that the conjecture is true in dimension three and four when g is weakly Einstein. In higher dimensional case $n{\geq}5$, we also show that the conjecture is true under an additional Ricci curvature bound. Moreover, we prove that the manifold is isometric to a standard n-sphere when it is n-dimensional weakly Einstein and the kernel of the linearized scalar curvature operator is nontrivial.

• Bulletin of the Korean Mathematical Society
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• v.46 no.2
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• pp.311-319
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• 2009

Let H be a Hilbert space which is the direct sum of five closed subspaces $X_0,\;X_1,\;X_2,\;X_3$ and $X_4$ with $X_1,\;X_2,\;X_3$ of finite dimension. Let J be a $C^{1,1}$ functional defined on H with J(0) = 0. We show the existence of at least four nontrivial critical points when the sublevels of J (the torus with three holes and sphere) link and the functional J satisfies sup-inf variational inequality on the linking subspaces, and the functional J satisfies $(P.S.)^*_c$ condition and $f|X_0{\otimes}X_4$ has no critical point with level c. For the proof of main theorem we use the nonsmooth version of the classical deformation lemma and the limit relative category theory.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1090-1093
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• 1987

In this paper, we describe the principle, the procedure and calculation of the measurement. Finally the experimental results are shown and discussions are given. Interpreting of a skewed symmetry in the image as a real symmetry in the 3-D space provides strong constraints on 3-D sharp analysis. In order to apply the idea to the real scene, a method is presented which can find the skewed symmetry in the image of the skewed symmetrical object, even if it is occluded partly. there parameters of the skewed symmetry are estimated by examining peaks in two 2-D hough spaces, onto which the parameters of all candidates of boundary line segments for skewed symmetries are voted. The method is characterized with a small amount of computation, finding of multiple symmetry axes and inference of the occluded parts of the symmetrical object.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11c
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• pp.1911-1914
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• 2002

이 논문에서는 여러 가지 위상 관계 표현 방법을 바탕으로 3 차원 공간 객체들 간의 위상 관계를 여러 가지 방법으로 표현한다. 지리정보시스템 분야에서 공간 객체들 간의 위상 관계를 정의하는 것은 중요한 연구이다. 위상 관계를 표현하는 기존의 방법들은 2 차원 공간 객체를 대상으로 하고있다. 좀더 많은 공간 정보를 제공하기 위해, 3 차원 공간 데이터에 대한 위상 관계를 표현하고 정의한다. 또한, 4-intersection, 9-intersection, dimension extended, calculus-based 방법 등, 여러 연구에서 제시되었던 표현 방법을 사용하여 위상 관계를 정의한다.

• International Journal of Knowledge Content Development & Technology
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• v.6 no.1
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• pp.5-39
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• 2016

Social networking applications (SNAs) are among the fastest growing web applications of recent years. In this paper, we propose a causal model to assess the success of SNAs, grounded on DeLone and McLean's updated information systems (IS) success model. In addition to their original three dimensions of quality, i.e., system quality, information quality and service quality, we propose that a fourth dimension - networking quality - contributes to SNA success. We empirically examined the proposed research model with a survey of 168 Facebook and 149 Twitter users. The data validates the significant role of networking quality in determining the focal SNA's success. The theoretical and practical implications are discussed.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.1018-1023
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• 1993

In mechanical structure design area, many FEM (Finite Element Method) packages are used. But the design using FEM packages depends on an iterative trial and error manner and general CAD systems cannot cope with the change of parameters. This paper presents a methodology for building a designing system of a mechanical structure. This system can generate the drawing for a designed structure automatically. It consists of three steps: generation of a structure by selection of the parameters, stress analysis, and generation of a drawing using CAD system. FEM module and parametric CAD module are developed for this system. Inference engine module generates the parameters with a rule base and a model base, and also evaluates the current structure. The parametric design module generates geometric shapes automatically with given dimension. Parametric design is implemented with the artificial intelligent technique. In older to the demonstrate the effectiveness of the developed system, a frame set of bicycle was designed. The system was implemented on an SUN workstation using C language under OpenWindows environment.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.4
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• pp.379-384
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• 2009

A human gaze detection and tracing method is importantly required for HMI(Human-Machine-Interface) like a Human-Serving robot. This paper proposed a novel three-dimension (3D) human gaze estimation method by using a face recognition, an orientation estimation and SVMs (Support Vector Machines). 2,400 images with the pan orientation range of $-90^{\circ}{\sim}90^{\circ}$ and tilt range of $-40^{\circ}{\sim}70^{\circ}$ with intervals unit of $10^{\circ}$ were used. A stereo camera was used to obtain the global coordinate of the center point between eyes and Gabor filter banks of horizontal and vertical orientation with 4 scales were used to extract the facial features. The experiment result shows that the error rate of proposed method is much improved than Liddell's.