• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.37-40
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• 2002

본 논문에서는 MISO(Multiple-Input Single-Output) 시스템에서 시공간 블록 부호(Space-Time Block Code; STBC)와 전송 고유빔 형성기의 결합을 통해 전송 다이버시티 이득과 빔형성 이득을 동시에 추구하는 기법에 대해 설명하였다. 빔형성 이득을 대한 성능을 분석하기 위해 채널간 상관 정도에 따라 모의실험을 통해 성능을 분석하였다. 성능 분석 결과 일반적인 STBC 기법을 적용하는 기법보다 우수한 성능을 보임을 확인하였다

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.4
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• pp.307-314
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• 2009

The present paper briefly describes the space frame element and the fundamental strategies in computational elastic bifurcation theory of geometrically nonlinear, single load parameter conservative elastic spatial structures. A method for large deformation(rotation) analysis of space frame is based on an eulerian formulation, which takes into consideration the effects of large joint translations and rotations with finite deformation(rotation). The local member force-deformation relationships are based on the beam-column approach, and the change in member chord lengths caused by axial strain and flexural bowing are taken into account. and the derived geometric stiffness matrix is unsymmetric because of the fact that finite rotations are not commutative under addition. To detect the singular point such as bifurcation point, an iterative pin-pointing algorithm is proposed. And the path switching mode for bifurcation path is based on the non-negative eigen-value and it's corresponding eigen-vector. Some numerical examples for bifurcation analysis are carried out for a plane frame, plane circular arch and space dome structures are described.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.3 no.1
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• pp.47-52
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• 2010

In this paper, we introduce a new approach for real-time 3D face pose discrimination based on active IR illumination from a monocular view of the camera. Under the IR illumination, the pupils appear bright. We develop algorithms for efficient and robust detection and tracking pupils in real time. Based on the geometric distortions of pupils under different face orientations, an eigen eye feature space is built based on training data that captures the relationship between 3D face orientation and the geometric features of the pupils. The 3D face pose for an input query image is subsequently classified using the eigen eye feature space. From the experiment, we obtained the range of results of discrimination from the subjects which close to the camera are from 94,67%, minimum from 100%, maximum.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.3
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• pp.727-732
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• 2004

In this paper, we introduce a new approach for real-time 3D face pose discrimination based on active IR illumination from a monocular view of the camera. Under the IR illumination, the pupils appear bright. We develop algorithms for efficient and robust detection and tracking pupils in real time. Based on the geometric distortions of pupils under different face orientations, an eigen eye feature space is built based on training data that captures the relationship between 3D face orientation and the geometric features of the pupils. The 3D face pose for an input query image is subsequently classified using the eigen eye feature space. From the experiment, we obtained the range of results of discrimination from the subjects which close to the camera are from 94,67％, minimum from 100％, maximum.

• Journal of the Korea Computer Graphics Society
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• v.12 no.2
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• pp.1-7
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• 2006

블렌드 쉐입 기반 얼굴 애니메이션을 위해 기저 모델(Expression basis)을 생성하는 방법을 크게 두 가지로 구분하면, 애니메이터가 직접 모델링을 하여 생성하는 방법과 통계적 방법에 기초하여 모델링하는 방법이 있다. 그 중 애니메이터에 의한 수동 모델링 방법으로 생성된 기저 모델은 직관적으로 표정을 인식할 수 있다는 장점으로 인해 전통적인 키프레임 제어가 가능하다. 하지만, 표정 공간(Expression Space)의 일부분만을 커버하기 때문에 모션데이터로부터의 재복원 과정에서 많은 오차를 가지게 된다. 반면, 통계적 방법을 기반으로 한 기저모델 생성 방법은 거의 모든 표정공간을 커버하는 고유 얼굴 모델(Eigen Faces)을 생성하므로 재복원 과정에서 최소의 오차를 가지지만, 시각적으로 직관적이지 않은 표정 모델을 만들어 낸다. 따라서 본 논문에서는 수동으로 생성한 기저모델을 유사 고유 얼굴 모델(Quasi-Eigen Faces)로 변형하는 방법을 제시하고자 한다. 결과로 생성되는 기저 모델은 시각적으로 직관적인 얼굴 표정을 유지하면서도 통계적 방법에 의한 얼굴표정 공간의 커버 영역과 유사하도록 확장할 수 있다.

• Journal of Institute of Control, Robotics and Systems
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• v.1 no.2
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• pp.105-111
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• 1995

This paper proposes a segmentation algorithm using gray-level discontinuity and surface reflectance ratio of input images obtained under different illumination conditions. Each image is divided by a certain number of subregions based on the thresholds. The thresholds are determined using the histogram of fusion image which is obtained by ANDing the multiple input images. The subregions of images are projected on the eigenspace where their bases are the major eigenvectors of image matrix. Points in the eigenspace are classified into two clusters. Images associated with the bigger cluster are fused by revised ANDing to form a combined edge image. Missing edges are detected using surface reflectance ration and chain code. The proposed algorithm obtains more accurate edge information and allows to more efficiently recognize the environment under various illumination conditions.

• Journal of Korean Society of Steel Construction
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• v.24 no.3
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• pp.337-348
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• 2012

This study investigated the characteristics of bifurcation and the instability due to the initial imperfection of the space truss, which is sensitive to the initial conditions, and the calculated buckling load by the analysis of Eigen-values and the determinant of tangential stiffness. A two-free nodes model, a star dome, and a three-ring dome model were selected as case studies in order to examine the unstable phenomenon due to the sensitivity to Eigen mode, and the influence of the rise-span ratio and the load parameter on the buckling load were analyzed. The sensitivity to the imperfection of the two-free nodes model changed the critical path after reaching the limit point through the bifurcation mode, and the buckling load level was reduced by the increase in the amount of imperfection. The two sensitive buckling patterns for the model can be explained by investigating the displaced position of the free node, and the asymmetric Eigen mode was a major influence on the unstable behavior due to the initial imperfection. The sensitive mode was similar to the in-extensional mechanism basis of the simplified model. Since the rise-span ratio was higher, the effect of local buckling is more prominent than the global buckling in the star dome, and bifurcation on the equilibrium path occurring as the value of the load parameter was higher. Additionally, the buckling load levels of the star dome and the three-ring model were about 50-70% and 80-90% of the limit point, respectively.

• Journal of Broadcast Engineering
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• v.15 no.1
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• pp.122-132
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• 2010

AT-DMB system has been developed to increase data rate up to double of conventional T-DMB in the same bandwidth while maintaining backward compatibility. The AT-DMB system adopted hierarchical modulation which adds BPSK or QPSK signal as enhancement layer to existing DQPSK signal. The enhancement layer signal should be small enough to maintain backward compatibility and to minimize the coverage loss of conventional T-DMB service coverage. But this causes the enhancement layer signal of AT-DMB susceptible to fading effect in transmission channel. A turbo code which has improved error correction capability than convolutional code, is applied to the enhancement layer signal of the AT-DMB system for compensating channel distortion. However there is a need for other solutions for better reception of AT-DMB signal in receiver side without increasing transmitting power. In this paper, we propose adaptive array antenna system with Eigen-space beamforming algorithm which benefits beamforming gain along with diversity gain. We analyzed the reception performances of AT-DMB system in indoor and mobile environments when this new smart antenna system and algorithm is introduced. The computer simulation results are presented along with analysis comments.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.44 no.3
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• pp.98-107
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• 2007

For high-dimensional pattern recognition, such as face classification, the small number of training samples leads to the Small Sample Size problem when the number of pattern samples is smaller than the number of dimensionality. Recently, various LDA-extensions have been developed, including LDA, PCA+LDA, and Direct-LDA, to address the problem. This paper proposes a method of improving the classification efficiency by increasing the number of (sub)-classes through pre-clustering a training set prior to the execution of Direct-LDA. In LDA (or Direct-LDA), since the number of classes of the training set puts a limit to the dimensionality to be reduced, it is increased to the number of sub-classes that is obtained through clustering so that the classification performance of LDA-extensions can be improved. In other words, the eigen space of the training set consists of the range space and the null space, and the dimensionality of the range space increases as the number of classes increases. Therefore, when constructing the transformation matrix, through minimizing the null space, the loss of discriminatve information resulted from this space can be minimized. Experimental results for the artificial data of X-OR samples as well as the bench mark face databases of AT&T and Yale demonstrate that the classification efficiency of the proposed method could be improved.

• Bulletin of the Korean Mathematical Society
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• v.36 no.3
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• pp.467-476
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• 1999

In the present paper, we describe the action of isometry groups of 30dimensional weakly symmetric spaces and classify 3-dimensional connected weaky symmetric spaces. Further, we determine 3-dimensional weakly symmetric spaces in terms of the eigen- values of the Ricci transformation.