• Title/Summary/Keyword: uniform grid

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Study of Facial Expression Recognition using Variable-sized Block (가변 크기 블록(Variable-sized Block)을 이용한 얼굴 표정 인식에 관한 연구)

  • Cho, Youngtak;Ryu, Byungyong;Chae, Oksam
    • Convergence Security Journal
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    • v.19 no.1
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    • pp.67-78
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    • 2019
  • Most existing facial expression recognition methods use a uniform grid method that divides the entire facial image into uniform blocks when describing facial features. The problem of this method may include non-face backgrounds, which interferes with discrimination of facial expressions, and the feature of a face included in each block may vary depending on the position, size, and orientation of the face in the input image. In this paper, we propose a variable-size block method which determines the size and position of a block that best represents meaningful facial expression change. As a part of the effort, we propose the way to determine the optimal number, position and size of each block based on the facial feature points. For the evaluation of the proposed method, we generate the facial feature vectors using LDTP and construct a facial expression recognition system based on SVM. Experimental results show that the proposed method is superior to conventional uniform grid based method. Especially, it shows that the proposed method can adapt to the change of the input environment more effectively by showing relatively better performance than exiting methods in the images with large shape and orientation changes.

A Simple Volume Tracking Method For Compressible Two-Phase Flow

  • SHYUE KEH-MING
    • Journal of The Korean Astronomical Society
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    • v.34 no.4
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    • pp.237-241
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    • 2001
  • Our goal is to present a simple volume-of-fluid type interface-tracking algorithm to compressible two-phase flow in two space dimensions. The algorithm uses a uniform underlying Cartesian grid with some cells cut by the tracked interfaces into two subcells. A volume-moving procedure that consists of two basic steps: (1) the update of volume fractions in each grid cell at the end of the time step, and (2) the reconstruction of interfaces from discrete set of volume fractions, is employed to follow the dynamical behavior of the interface motion. As in the previous work with a surface-tracking procedure for general front tracking (LeVeque & Shyue 1995, 1996), a high resolution finite volume method is then applied on the resulting slightly nonuniform grid to update all the cell values, while the stability of the method is maintained by using a large time step wave propagation approach even in the presence of small cells and the use of a time step with respect to the uniform grid cells. A sample preliminary numerical result for an underwater explosion problem is shown to demonstrate the feasibility of the algorithm for practical problems.

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Investigation of Large-scale Transmission Tower Grounding Grid with High Amplitude and Uniform Flowing Impulse Current

  • Yang, Shuai;Huang, Jiarui;Wei, Shaodong;Zhou, Wenjun
    • Journal of Electrical Engineering and Technology
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    • v.13 no.5
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    • pp.2050-2058
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    • 2018
  • Impulse characteristic of transmission tower grounding grid is needed for lightning protection of transmission line. This paper describes an outdoor experimental test facility established for large-scale grounding grid of transmission tower, made up of four impulse current generators and a circle current return electrode. The amplitude of impulse current is up to 100 kA. The results of the CDEGS simulation and GPR measurement reveal the uniform current distribution in the test arrangement. An impulse test for a square electrode with extended conductors is carried out in condition of three current waveforms with different amplitude. Based on the electrical network model and iterative algorithm method, a calculation model is proposed to simulate the impulse characteristic of large-scale grounding grid considering soil ionization. The curve of impulse resistance against the current amplitude shows the soil ionization both from the simulation and test. Deviation between the simulation and test result is less than 15%.

An Integrated Toolset for Distributed Real-Time Systems Based on Computational Grid

  • Zhang, Lichen
    • Proceedings of the IEEK Conference
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    • 2002.07a
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    • pp.309-312
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    • 2002
  • Advances in networking infrastructure have led to the development of a new type of "computational grid" infrastructure that provides predictable, consistent and uniform access to geographically distributed resources such as computers, data repositories, scientific instruments, and advanced display devices Such Grid environments are being used to construct sophisticated, performance-sensitive applications in such areas as dynamic, distributed real-time applications. In this paper, we propose a toolset for designing distributed real-time systems based on computational grid. The toolset is based on a new methodology and integrates the models that methodology Proposed for designing real-time systems.

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Tetrahedral Mesh Generation Using a Mixed Method of a Grid and an Advancing Front Approach (격자법과 전진경계법을 흔합한 사면체 요소망의 자동생성)

  • 김영웅;전성재;채수원
    • Korean Journal of Computational Design and Engineering
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    • v.8 no.1
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    • pp.41-47
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    • 2003
  • In this paper, a tetrahedral mesh generation algorithm which uses a grid based method for interior region and an advancing front method for outer surface region is proposed. In order to apply an advancing front method for outer region of an object, a new operator so called a hole operator has been developed to handle multiple shells. With this grid based approach in the interior region, more stable and uniform meshes can be constructed especially in the interior region.

Triangular Mesh Generation using non-uniform 3D grids (Non-uniform 3D grid를 이용한 삼각형망 생성에 관한 연구)

  • 강의철;우혁제;이관행
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.1283-1287
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    • 2003
  • Reverse engineering technology refers to the process that creates a CAD model of an existing part using measuring devices. Recently, non-contact scanning devices have become more accurate and the speed of data acquisition has increased drastically. However, they generate thousands of points per second and various types of point data. Therefore. it becomes a important to handle the huge amount and various types of point data to generate a surface model efficiently. This paper proposes a new triangular mesh generation method using 3D grids. The geometric information of a part can be obtained from point cloud data by estimating normal values of the points. In our research, the non-uniform 3D grids are generated first for feature based data reduction based on the geometric information. Then, triangulation is performed with the reduced point data. The grid structure is efficiently used not only for neighbor point search that can speed up the mesh generation process but also for getting surface connectivity information to result in same topology surface with the point data. Through this integrated approach, it is possible to create surface models from scanned point data efficiently.

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A Space-Tapering Approach for a Rectangular Array (직사각형 어레이를 위한 공간체감 방법)

  • Chang, Byong-Kun
    • The Journal of the Acoustical Society of Korea
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    • v.14 no.1
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    • pp.115-122
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    • 1995
  • It is practical to taper the element (e.g., antenna or sensor) spacing with uniform weight rather than to taper the weights with uniform spacing. In a rectangular array, a triangular grid geometry of elements is more economical than a rectangular grid geometry in terms of reducing the number of elements. A space-tapering approach is proposed to improve the performance of a rectangular phased array with a triangular grid geometry of elements above a ground plane. The effects of space tapering on the main beam width and sidelobe level are discussed. It is shown that the proposed approach improves the sidelobe performance while the main beam width becomes a little broader.

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3D SIMULATION OF FLAPPING FLAGS IN A UNIFORM FLOW BY THE IMMERSED BOUNDARY METHOD

  • Huang, Wei-Xi;Sung, Hyung-Jin
    • 한국전산유체공학회:학술대회논문집
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    • 2007.10a
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    • pp.141-148
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    • 2007
  • We present an immersed boundary (IB) method for 3D simulation of flappingflags in a uniform flow. The proposed formulation is manipulated on the basis of an efficient Navier-Stokes solver adopting the fractional step method and a staggered Cartesian grid system. A direct numerical method is developed to calculate the flag motion, with the elastic force treated implicitly. The fluid motion defined on an Eulerian grid and the flag motion defined on a Lagrangian grid are independently solved and the mass of flag is handled in a natural way. An additional momentum forcing is formulated from the flag motion equation in a way similar with the direct-forcing IB formulation and acts as the interaction force between the flag and ambient fluid. A series of numerical tests are performed and the present results are compared qualitatively and quantitatively with previous studies. The instantaneous flag motion is analyzed under different conditions and surrounding vortical structures are identified. The effects of physical parameters on the flapping frequency are studied.

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Grid Generation about Full Aircraft Configuration Using Interactive Grid Generator (상호 대화형 격자생성 환경을 이용한 항공기 전기체 격자계 생성)

  • Kim Y. S.;Kwon J. H.
    • 한국전산유체공학회:학술대회논문집
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    • 1999.11a
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    • pp.145-151
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    • 1999
  • An Interactive grid generation program(KGRID) with graphical user interface(GUI) has been improved. KGRID works on the UNLX environment and GUI has been implemented with OSF/Motif and X Toolkit and the graphics language is Open GL for visualization of the 3D objects. It supports more convenient user environment to generate 2D and 3D multi-block structured grid systems. It provides various useful field grid generation methods, which are the algebraic methods, the elliptic partial differential equations method and the predictor-corrector method. It also supports 3D surface grid generation with NURBS(Non-Uniform Rational B-Spline) and various stretching functions to control grid points distribution on curves and surfaces. And some menus are added to perform flexible management, for the objects. We generated surface and field grid system about full aircraft configuration using KGRID. The performance and stability of the KGRID is verified through the generation of the grid system about a complex shape.

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