• 제목/요약/키워드: geometrical structures

검색결과 599건 처리시간 0.023초

보르노이 다이어그램을 이용한 지문정합 알고리즘 (Fingerprint Identification Using Voronoi Diagram)

  • 김승훈;최태영
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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    • pp.301-304
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    • 2003
  • This raper propose a matching algorithm using voronoi diagram for rotation and translation invariant fingerprint identification. The proposed algorithm extracts geometrical structures that ate derived from voronoi diagram of a fingerprint image. Then distances and angles are extracted from the geometrical structure and saved indexing form for fingerprint matching. Experimental results show that the proposed algorithm invariant to fingerprint rotation and translation requirements and matching time.

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기하학적 픽셀 값과 히스토그램을 값을 사용한 건널목에서의 물체 검출에 관한 연구 (A Study on the Object(Human) Detection methods using Geometrical Pixel Value and Histograms Value at the railroad crossing)

  • 김윤집;권용진;신석균;이기서
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2002년도 추계학술대회 논문집(I)
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    • pp.566-573
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    • 2002
  • In this paper, is propose to the object(human) dection method using geometrical structures and projection histograms in the image. The problem of existing methods for objects tracking of background subtracted is resulted from uncertainty at background unfixed. In this paper, two methods are applied to solve problem. This problems are proved by method. This problems is demonstrated by using this methods and applied to the train railroad crossing. Therefore, this paper aims that this contributes to improve the accident of the train railroad crossing.

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The Lecomte-Ueda Transformation and Resonance Structure in the Multichannel Quantum Defect Theory for the Two Open and One Closed Channel System

  • Lee, Chun-Woo;Kim, Ji-Hyun
    • Bulletin of the Korean Chemical Society
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    • 제23권11호
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    • pp.1560-1567
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    • 2002
  • The transformation devised by Lecomte and Ueda for the study of resonance structures in the multichannel quantum defect theory (MQDT) is used to analyze partial photofragmentation cross section formulas in MQDT analogous to Fano's resonance formula obtained in the previous work for the system involving two open and one closed channels. Detailed comparison of the MQDT results with the configuration mixing (CM) ones is made. Resonance structures and their geometrical relations in the MQDT formulation are revealed and classified by combining Lecomte and Ueda's theory with the geometrical method devised to study the coupling between background and resonance scatterings.

Dynamic Instability of Lattice-Dome Structures by Lyapunov Concept

  • Han, Sang-Eul;Hou, Xiao-Wu
    • Architectural research
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    • 제10권1호
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    • pp.25-32
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    • 2008
  • Stability is a very important part which we must consider in structural design. In this paper, we take advantage of finite element method to study parametrical instability of lattice dome structures, which is subjected to harmonically pulsating load. We consider elastic stiffness and geometrical stiffness simultaneously during the calculation of stiffness matrix, and adopt consistent mass matrix to make the solution more correct. In order to obtain instability regions, we represent displacements and accelerations in dynamic equation by trigonometric series expansions, and then obtain Hill's infinite determinants. After first order approximation, we can get first and second order dynamic instability regions eventually. Finally, we take 24-bar star dome and 90-bar lamella dome as examples to investigate dynamic instability phenomena.

Stochastic finite element analysis of structural systems with partially restrained connections subjected to seismic loads

  • Cavdar, Ozlem;Bayraktar, Alemdar;Cavdar, Ahmet;Kartal, Murat Emre
    • Steel and Composite Structures
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    • 제9권6호
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    • pp.499-518
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    • 2009
  • The present paper investigates the stochastic seismic responses of steel structure systems with Partially Restrained (PR) connections by using Perturbation based Stochastic Finite Element (PSFEM) method. A stiffness matrix formulation of steel systems with PR connections and PSFEM and MCS formulations of structural systems are given. Based on the formulations, a computer program in FORTRAN language has been developed, and stochastic seismic analyses of steel frame and bridge systems have been performed for different types of connections. The connection parameters, material and geometrical properties are assumed to be random variables in the analyses. The Kocaeli earthquake occurred in 1999 is considered as a ground motion. The connection parameters, material and geometrical properties are considered to be random variables. The efficiency and accuracy of the proposed SFEM algorithm are validated by comparison with results of Monte Carlo simulation (MCS) method.

적층된 ACM 경사판의 기하학적 비선형 동적 해석 (Geometrical nonlinear dynamic analysis of laminated skew plates made of advanced composite materials)

  • 이상열;장석윤
    • 복합신소재구조학회 논문집
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    • 제1권4호
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    • pp.28-34
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    • 2010
  • W e performed a geometrical nonlinear dynamic analysis of laminated skew plates made of advanced composite materials (ACM ) based on the first-order shear deformation plate theory (FSDT). The Newmark method and Newton-Raphson iteration are used for the nonlinear dynamic solution. The effects of skew angles and layup sequences on the nonlinear dynamic response for various parameters are studied using a nonlinear dynamic finite element program developed for this study. The several numerical results were in good agreement with those reported by other investigators for square composite and skew plates, and the new results reported in this paper show the significant interactions between the skew angle and layup sequence in the skew laminate. Key observation points are discussed and a brief design guideline is given.

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Stability of tow-steered curved panels with geometrical defects using higher order FSM

  • Fazilati, Jamshid
    • Steel and Composite Structures
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    • 제28권1호
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    • pp.25-37
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    • 2018
  • For the first time, the parametric instability characteristics of tow-steered variable stiffness composite laminated (VSCL) cylindrical panels is investigated using B-spline finite strip method (FSM). The panel is considered containing geometrical defects including cutout and delamination. The material properties are assumed to vary along the panel axial length of any lamina according to a linear fiber-orientation variation. A uniformly distributed inplane longitudinal loading varies harmoni-cally with time is considered. The instability load frequency regions corresponding to the assumed in-plane parametric load-ing is derived using the Bolotin's first order approximation through an energy approach. In order to demonstrate the capabili-ties of the developed formulation in predicting stability behavior of the thin-walled VSCL structures, some representative results are obtained and compared with those in the literature wherever available. It is shown that the B-spline FSM is a proper tool for extracting the stability boundaries of perforated delaminated VSCL panels.

Non-linear static analysis and design of Tensegrity domes

  • Fu, Feng
    • Steel and Composite Structures
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    • 제6권5호
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    • pp.417-433
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    • 2006
  • In this paper, a non-linear structural analysis software with pro-processing and post-recessing function is proposed by the author. The software incorporating the functions of the structural analysis and geometrical design of Tensegrity structures. Using this software, Cable Dome is analyzed as a prototype, a comprehensive study on the structural behavior of Tensegrity domes is presented in detail. Design methods of Tensegrity domes were proposed. Based on the analysis, optimizing design was performed. Several new Tensegrity domes with different geometrical design scheme are proposed, the structural analysis of the new schemes is also conducted. The analysis result shows that the proposed new forms of the Tensegrity domes are reasonable for practical applications.

Free vibration of AFG beams with elastic end restraints

  • Bambaeechee, Mohsen
    • Steel and Composite Structures
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    • 제33권3호
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    • pp.403-432
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    • 2019
  • Axially functionally graded (AFG) beams are a new class of composite structures that have continuous variations in material and/or geometrical parameters along the axial direction. In this study, the exact analytical solutions for the free vibration of AFG and uniform beams with general elastic supports are obtained by using Euler-Bernoulli beam theory. The elastic supports are modeled with linear rotational and lateral translational springs. Moreover, the material and/or geometrical properties of the AFG beams are assumed to vary continuously and together along the length of the beam according to the power-law forms. Accordingly, the accuracy, efficiency and capability of the proposed formulations are demonstrated by comparing the responses of the numerical examples with the available solutions. In the following, the effects of the elastic end restraints and AFG parameters, namely, gradient index and gradient coefficient, on the values of the first three natural frequencies of the AFG and uniform beams are investigated comprehensively. The analytical solutions are presented in tabular and graphical forms and can be used as the benchmark solutions. Furthermore, the results presented herein can be utilized for design of inhomogeneous beams with various supporting conditions.