• Title/Summary/Keyword: Grid Structures

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Numerical Requirements for the Simulation of Detonation Cell Structures (데토네이션 셀 구조 모사를 위한 수치적 요구 조건)

  • Choi Jeong-Yeol;Cho Deok-Rae
    • Journal of the Korean Society of Propulsion Engineers
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    • v.10 no.2
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    • pp.1-14
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    • 2006
  • Present study examines the numerical issues of cell structure simulation for various regimes of detonation phenomena ranging from weakly unstable to highly unstable detonations. Inviscid fluid dynamics equations with $variable-{\gamma} $ formulation and one-step Arrhenius reaction model are solved by a MUSCL-type TVD scheme and 4th order accurate Runge-Kutta time integration scheme. A series of numerical studies are carried out for the different regimes of the detonation phenomena to investigate the computational requirements for the simulation of the detonation wave cell structure by varying the reaction constants and grid resolutions. The computational results are investigated by comparing the solution of steady ZND structure to draw out the minimum grid resolutions and the size of the computational domain for the capturing cell structures of the different regimes of the detonation phenomena.

Applications of Haar Wavelet Based Multiresolution Time-Domain Method to Microwave Structures (Haar 웨이블릿 다중분해능 시간영역 해석법을 이용한 마이크로파 소자 해석)

  • 주세훈;김형훈;김형동
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.10 no.6
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    • pp.935-950
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    • 1999
  • A multiresolution time-domain analysis scheme is derived for the analysis of microwave structures by using Haar wavelets to discretize the Maxwell's curl equation. This technique requires less computational effort than the conventional FDTD method because larger space grid can be used in the simulations. To validate this scheme, several 2-D·3-D microwave structures are simulated and the results are compared with those of the conventional FDTD scheme.

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Buckling Analysis of Spherical Shells that Rigidity-Distribution has Periodicity (강성분포가 주기성을 갖는 구형쉘의 좌굴해석)

  • Park, Sang-Hoon
    • Journal of Korean Association for Spatial Structures
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    • v.2 no.4 s.6
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    • pp.45-52
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    • 2002
  • Research about spherical shells been applying most usually is achieved by many investigators already and generalized equation has been derived. But, existent research is limited in case that spherical shell's roof rigidity is isotropy or orthotropy, and research that consider periodicity of rigidity-distribution that can happen by doing spherical shell's roof system by lattice system is not gone entirely. The purpose of this paper is applying Galerkin method to spherical shell that model periodicity of roof rigidity distribution that appear by roof lattice form of large space structure and develop structural analysis program that formularize. Rigidity-model of this research selects that of spherical shell which has 2-way grid. In this paper, buckling-strength and deformation distribution of isotopic spherical shell and 2-way grid spherical shell obtained by developed program could confirm the reliability by comparison with result of existent research.

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Vibration Suppression of Smart Structures Using PPF and SRF Control Techniques (PPF와 SRF 제어기법을 사용한 지능구조물의 능동진동제어)

  • 라완규;곽문규;윤광준
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1997.04a
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    • pp.400-406
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    • 1997
  • This paper is concerned with the active vibration control of grid structure by means of piezoceramic actuators and sensors. The control technique used in this paper is based on the positive position feedback(PPF) and the strain rate feedback(SRF) control, which have been successfully used for the vibration control of beam structures. A new control methodology is developed using the PPF and SRF controller of single-input single-output method. The PPF controller is used for the suppression of first bending mode and SRF controller is used for the suppression of higher vibration modes of grid structure. Electric circuits for the realization of control schemes are explained in detail. The control techniques prove its effectiveness by experiments.

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Structural optimization and proposition of pre-sizing parameters for beams in reinforced concrete buildings

  • de Medeiros, Guilherme Fleith;Kripka, Moacir
    • Computers and Concrete
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    • v.11 no.3
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    • pp.253-270
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    • 2013
  • The aim of the present paper is to show the application of optimization strategies for the cost of beams in reinforced concrete buildings and to propose pre-sizing parameters. In order for these goals to be met, an optimization software program was developed. The program combines the analysis of structures by the grid model, reinforced concrete sizing, and the simulated annealing optimization heuristic. Sizing is compliant with the NBR 6118 (2007) Brazilian standard, according to which flexural, shearing, torsion, and web reinforcements and serviceability limit states (deflection and crack width limitation) are checked. Besides the dimensions of the situations mentioned above, the influence the cost of each material (steel, concrete and formwork) has on the overall cost of structures was also determined.

Design of Spatial Clustering Method for Data Mining of Various Spatial Objects (다양한 공간객체의 데이터 마이닝을 위한 공간 클러스터링 기법의 설계)

  • 문상호;최진오;김진덕
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.8 no.4
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    • pp.955-959
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    • 2004
  • Existing Clustering Methods for spatial data mining process only Point objects, not spatial objects with polygonometry such as lines and areas. It is because that distance computation between objects with polygonometry for clustering is more complex than distance computation between point objects. To solve this problem, we design a clustering method based on regular grid cell structures. In details, it reduces cost and time for distance computation using cell relationships in grid cell structures.

Design of Spatial Clustering Method for Spatial Objects with Polygonometry (다각형 객체를 지원하는 공간 클러스터링 기법의 설계)

  • 황지완;문상호
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2004.05b
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    • pp.374-377
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    • 2004
  • Existing Clustering Methods for spatial data mining process only point objects, not objects with polygonometry such as lines and areas. It is because that distance computation between objects with polygonomery for clustering is more complex than point objects. To solve this problem, we design a clustering method based on regular grid cell structures. In details, it refutes cost and time for distance computation using cell relationships in grid cell structures.

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Synthesis of Graphene Using Thermal Chemical Vapor Deposition and Application as a Grid Membrane for Transmission Electron Microscope Observation (열화학증기증착법을 이용한 그래핀의 합성 및 투과전자현미경 관찰용 그리드 멤브레인으로의 응용)

  • Lee, Byeong-Joo;Jeong, Goo-Hwan
    • Korean Journal of Materials Research
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    • v.22 no.3
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    • pp.130-135
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    • 2012
  • We present a method of graphene synthesis with high thickness uniformity using the thermal chemical vapor deposition (TCVD) technique; we demonstrate its application to a grid supporting membrane using transmission electron microscope (TEM) observation, particularly for nanomaterials that have smaller dimensions than the pitch of commercial grid mesh. Graphene was synthesized on electron-beam-evaporated Ni catalytic thin films. Methane and hydrogen gases were used as carbon feedstock and dilution gas, respectively. The effects of synthesis temperature and flow rate of feedstock on graphene structures have been investigated. The most effective condition for large area growth synthesis and high thickness uniformity was found to be $1000^{\circ}C$ and 5 sccm of methane. Among the various applications of the synthesized graphenes, their use as a supporting membrane of a TEM grid has been demonstrated; such a grid is useful for high resolution TEM imaging of nanoscale materials because it preserves the same focal plane over the whole grid mesh. After the graphene synthesis, we were able successfully to transfer the graphenes from the Ni substrates to the TEM grid without a polymeric mediator, so that we were able to preserve the clean surface of the as-synthesized graphene. Then, a drop of carbon nanotube (CNT) suspension was deposited onto the graphene-covered TEM grid. Finally, we performed high resolution TEM observation and obtained clear image of the carbon nanotubes, which were deposited on the graphene supporting membrane.

A Study on the Construction and Deconstruction of the 'Grid' : The Historical Context and Interpretation ('그리드'(Grid)의 형성과 해체 -서양회화의 사적맥락과 그 해석을 중심으로 -)

  • Kim Jai-Kwan
    • Journal of Science of Art and Design
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    • v.1
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    • pp.125-164
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    • 1999
  • The Grid, a lattice structure adapted in paintings, is one of thesimplest plastic structures based on the intersection of horizontal and perpendicular lines. Though mankind has, from the pre-history to the present day, put it to good use in everyday life as a traditional practice or a magical, esoteric, religious emblem in the case of the teciform of primitve art, it was in the paintings of Piet Mondrian that the Grid showed its modern, artistic transformation. As we suggest in the title, before I state the Grid as a plastic construction of modern painting, this dissertation inquires the Grid structure that extends over paintings through the ages as a painterly conept, especially focused on their formation and deconstruction. To begin with, my dissertation investigates, as a historical background, a general idea of the geometrical structure and phases of its transition in art, prior to dealing with the Grids as plastic strures in modern painting. the core of my study on formal Grids is permeated through the third chapter. The first chapter concentrates on, firstly, difining the notion of the Grid and geometrical structure, secondly, searching for a historical backgrounb with whict the so- called modern Grid-paintings come in, inquiring into the formation of the illusion-Grid as aresult of discovering the linear perpective and the situation of the conflict and reconciliaton between reality and illusion. Based on these considerations, the second cecond chapter will examine the various sitations of formation and adaptation of the paintery Grids in the Literalism-Grid, as we have already seen in the chapter one. And the cardinal third chapter devotes itself to the process of the formation of the so-called Object-Grid and Literal-Grid in the Literalism or Minimalism as its logical extension of the Painterly Grid. With it we can get to an interpretation and understanding of the meaning and qualites of Grid dwelt in Modernism thst transformed the structure of Painterly Grid originally as a plane concept to the third dimentionl structure. And then, the fourth chapter, we try to draw a new meaning andre-interpretation of the Formal-Grid as a representatuinnal structure appeared in the post-modernist paintings, going with its deconstructional situation. Therefore, we can, in our study on Grids, see the various points of view in the interpretation of them as illusion-structure, as plane-structure, and as cubic-structure; its concept differs form times, oscillating between its formation and deconstruction. The Grid, as we have seen in my dissertation, contains various problems and significations in art that deserve to investigate throughly, including some important plastic problem such as space and plane, and, in the case of do-grid, time. We may expect new concepts of it that will have difference meanings. 1 hope my study makes some contributions to understanding the coordination of the abstruse modern and contemporary art.

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Visible Assessment of Earthquake-induced Geotechnical Hazards by Adopting Integrated Geospatial Database in Coastal Facility Areas (복합 공간데이터베이스 적용을 통한 해안 시설영역 지진 유발 지반재해의 가시적 평가)

  • Kim, Han-Saem;Sun, Chang-Guk
    • Journal of the Earthquake Engineering Society of Korea
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    • v.20 no.3
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    • pp.171-180
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    • 2016
  • Earthquake event keeps increasing every year, and the recent cases of earthquake hazards invoke the necessity of seismic study in Korea, as geotechnical earthquake hazards, such as strong ground motion, liquefaction and landslides, are a significant threat to structures in industrial hub areas including coastal facilities. In this study, systemized framework of integrated assessment of earthquake-induced geotechnical hazard was established using advanced geospatial database. And a visible simulation of the framework was specifically conducted at two coastal facility areas in Incheon. First, the geospatial-grid information in the 3D domain were constructed with geostatistical interpolation method composed of multiple geospatial coverage mapping and 3D integration of geo-layer construction considering spatial outliers and geotechnical uncertainty. Second, the behavior of site-specific seismic responses were assessed by incorporating the depth to bedrock, mean shear wave velocity of the upper 30 m, and characteristic site period based on the geospatial-grid. Third, the normalized correlations between rock-outcrop accelerations and the maximum accelerations of each grid were determined considering the site-specific seismic response characteristics. Fourth, the potential damage due to liquefaction was estimated by combining the geospatial-grid and accelerations correlation grid based on the simplified liquefaction potential index evaluation method.