• Investigative Magnetic Resonance Imaging
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• v.9 no.1
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• pp.2-8
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• 2005

Purpose : The purpose of this study was to implement a software to visualize tumor and its surrounding fiber tracts simultaneously using diffusion tensor imaging and examine the feasibility of our software for investigating the influence of tumor on its surrounding fiber connectivity. Material and Methods : MR examination including T1-weigted and diffusion tensor images of a patient with brain tumor was performed on a 3.0 T MRI unit. We used the skull-striped brain and segmented tumor images for volume/surface rendering and anatomical information from contrast-enhanced T1-weighted images. Diffusion tensor images for the white matter fiber-tractography were acquired using a SE-EPI with a diffusion scheme of 25 directions. Fiber-tractography was performed using the streamline and tensorline methods. To correct a spatial mismatch between T1-weighted and diffusion tensor images, they were coregistered using a SPM. Our software was implemented under window-based PC system. Results : We successfully implemented the integrated visualization of the fiber tracts with tube-like surfaces, cortical surface and the tumor with volume/surface renderings in a patient with brain tumor. Conclusion : Our result showed the feasibility of the integrated visualization of brain tumor and its surrounding fiber tracts. In addition, our implementation for integrated visualization can be utilized to navigate the brain for the quantitative analysis of fractional anisotropy to assess changes in the white matter tract integrity of edematic and peri-edematic regions in a number of tumor patients.

• Proceeding of KASS Symposium
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• 2005.05a
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• pp.77-82
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• 2005

Tensegrity is a relatively new sructural system (about more than 50 years old) based on the use of continuous tension-discontinuous compression. In spite of the controversial principles to define these systems, several examples of tensegrity prototypes constructed in IEDS(Institute of Environment Structure Design) are presented illustrating the feasibility of tensegrity as a lightweight structure. Of course, a much more detailed structural investigation would be necessary, but at least in order to achieve the intended purpose, it is essential to understand the structural principles and the fundamental forces of tensegrity. Once this point Is established, the characteristics of these structures are described, as well as applying them to architecture. Consequently, in this work, the patterns of basic module as well as fundamental definition are introduced. Then, the application of tensegrity to architecture has also been mentioned.

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.635-640
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• 2021

In this paper, we describe a parking space identification system that can automatically identify empty parking lot spaces from a parking lot photo. This system is based on a deep learning technique, and the accuracy of the identification result is good by learning various existing parking lot images. It could be applied to the existing parking management system. This system was also developed as a smartphone application for easy testing. Therefore, if you take a picture of a parking lot through a smartphone camera, the captured image is automatically recognized and an empty parking space can be automatically identified.

• Journal of Korean Association for Spatial Structures
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• v.14 no.4
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• pp.55-64
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• 2014

In this study, Intersecting Tensegrity System that is integrated solid compression members with tension members was presented. This system is set up by connecting upper and lower compression members of pyramid shape with exterior tension members. In this system, the solid compression members are intersected each other and connected by a tension member in the center. This system is a variation of Tensegrity system, has a improved feature that the system is able to induce prestresses in all of tension members easily by adjusting the distance of a tension member in the center. The proposed system was studied by modeling, and the structural behavior of the system was investigated by mechanical analysis of the model. Furthermore, the features of the structural behavior variations was investigated when the composition elements(total height, size of surface, intersection length, etc.) are changed variously. It was also showed that the system is able to be used as a temporary space structure system with a membrane roof of inverse conical shape.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.4
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• pp.54-62
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• 2018

As a part of realization of artificial intelligence signal(AI Signal), this study proposed an actuated signal algorithm based on vehicle queue length that estimates in real time by deep learning. In order to implement the algorithm, we built an API(COM Interface) to control the micro traffic simulator Vissim in the tensorflow that implements the deep learning model. In Vissim, when the link travel time and the traffic volume collected by signal cycle are transferred to the tensorflow, the vehicle queue length is estimated by the deep learning model. The signal time is calculated based on the vehicle queue length, and the simulation is performed by adjusting the signaling inside Vissim. The algorithm developed in this study is analyzed that the vehicle delay is reduced by about 5% compared to the current TOD mode. It is applied to only one intersection in the network and its effect is limited. Future study is proposed to expand the space such as corridor control or network control using this algorithm.

• The Journal of Korea Robotics Society
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• v.3 no.4
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• pp.300-307
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• 2008

This paper is concerned with face recognition for human-robot interaction (HRI) in robot environments. For this purpose, we use Tensor Subspace Analysis (TSA) to recognize the user's face through robot camera when robot performs various services in home environments. Thus, the spatial correlation between the pixels in an image can be naturally characterized by TSA. Here we utilizes face database collected in u-robot test bed environments in ETRI. The presented method can be used as a core technique in conjunction with HRI that can naturally interact between human and robots in home robot applications. The experimental results on face database revealed that the presented method showed a good performance in comparison with the well-known methods such as Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA) in distant-varying environments.

• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1883-1886
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• 1997

3차원 유한요소법에 정합 조건을 구현하기 위해 유한한 두께를 갖는 흡수체을 이용하였다. 흡수체는 자유공간과의 경계에서 모든 입사각에 대해 무반사특성을 갖으며, 일단 흡수체 내로 전파된 파는 흡수체의 끝에 도달하기 전에 흡수체를 통과하면서 충분히 손실되도록 하였다. 이러한 흡수체는 ${\varepsilon}_r$과 ${\mu}_r$에 비등방복소주대각텐서를 사용하여 구현된다. 구현된 흡수체층은 구형도파관에 적용하여, 전파상수를 이용하여 정합시킨 경우와 결과를 비교하였다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.01a
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• pp.243-246
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• 2018

본 논문에서는 2차원 공간상에서 상부에서 하부로 떨어지는 블록을 하부에서 피하는 게임에서 강화 학습에 사용되는 DQN 알고리즘을 이용하여 블록 피하기 에이전트를 구현하고 학습 통해 점점 더 높은 점수를 받는 모습을 확인하였다. 파이썬을 이용하여 게임을 구현한 후 텐서플로우를 이용하여 DQN를 이용한 에이전트를 구현하였다. 에이전트는 보상을 통한 학습을 통하여 점점 강화되도록 하였는데, 초기에는 무작위로 움직였으나, 환경으로부터 받는 보상으로 점점 더 능숙하게 피하는 모습을 관찰할 수 있었다. 본 구현에서는 4000번 정도의 게임 시행에서 아주 능숙하게 피하는 결과를 얻을 수 있었다.

• Geophysics and Geophysical Exploration
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• v.2 no.2
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• pp.86-95
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• 1999

This paper presents an efficient three-dimensional (3-D) modeling algorithm using the extended approximation to an electric field integral equation. Numerical evaluations of Green's tensor integral are performed in the spatial wavenumber domain. This approach makes it possible to reduce computing time, to handle smoothly varying conductivity model and to remove singularity problems encountered in the integration of Green's tensor at a source point. The responses obtained by 3-D modeling algorithm developed in this study are compared with those by the full integral equation for a thin-sheet EM scattering. The extensive analyses on the performance of modeling algorithm are made with the conductivity contrasts and source frequencies. These results show that the modeling algorithm are accurate up to the conductivity contrast of 1:16 and the frequency range of 100 Hz-100 kHz. The extended Born approximation, however, may produce inaccurate results for some source and model configurations in which the electric field is discontinuous across the conductivity boundary. We performed the modeling of a composite model of which conductivity varies continuously and this shows the modeling algorithm developed in this study is efficient for 3-D EM modeling. For a cross-hole source-receiver configuration a composite model of which conductivity varies continuously can be successfully simulated using this algorithm.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.9
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• pp.29-39
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• 2001

Dielectric cover effect of rectangular microstrip patch antenna on uniaxial substrates with airgap are studied. First, we derive Dyadic Green function for selected anisotropic material by constitutive relation and then formulate integral equations of electric fields using Fourier transform in space region. Using Galerkin's moment method, we discretize the electric field integral equations into the matrix form and select sinusoidal functions as basis functions. We verify the validity of numerical results and compare the results with existing ones in showing a good agreement between them. When the dielectric cover thickness is varied, the resonant frequencies and input impedances in the variation of air gap, patch length and thickness and permittivity of superstrate are presented and analyzed.