• Title, Summary, Keyword: inverse projection

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The Methodology in Historical Demography at the Cambridge Group (역사 인구학 방법론의 현황)

  • 이흥탁
    • Korea journal of population studies
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    • v.12 no.2
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    • pp.56-68
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    • 1989
  • The methodology in historical demography comprises the three core areas the family reconstitution method at the Institut National d' Ftudes Demographiques(I.N.E.D), the back projection at the Cambridge Group for the History of PopuJation and Social Struc-ture(HPSS). and the household-pattern analysis at the Cambridge Group and at the California Institute of Technology. The paper presents an outline of the family reconstitu-tion method and discusses the problems, both theoretical and methodological, arising from the problematic back projection vis-a-vis the usual inverse projection developed by Ronald D. Lee at Berkeley. Recent developments in the tield of the generalized inverse projection method designed 10 supplement the defects in the back projection and the inverse projection are presented. and for ease of explanation of the parish register data for the family reconstitution form (FRE). pre-modern Korean household register data are presented along with the parish register data of England and Wales that constitute the backbone of historical demography in pre-modern Europe. Possibilities of exploring the household pattern analysis method based on the Laslett-Hammel classification scheme for the mid-eighteenth-century Korean household register data are suggested.

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Damage Detection of Truss Structures Using Parametric Projection Filter Theory (파라메트릭 사양필터를 이용한 트러스 구조물의 손상 검출)

  • Mun, Hyo-Jun;Suh, Ill-Gyo
    • 한국공간정보시스템학회:학술대회논문집
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    • pp.29-36
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    • 2004
  • In this paper, a study of damage detection for 2-Dimensional Truss Structures using the parametric projection filter theory is presented. Many researchers are interested in inverse problem and one of solution procedures for inverse problems that are very effective is the approach using the filtering algorithm in conjunction with numerical solution methods. In filtering algorithm, the Kalman filtering algorithm is well known and have been applied to many kind of inverse problems. In this paper, the Parametric projection filtering in conjunction with structural analysis is applied to the identification of damages in 2-D truss structures. The natural frequency and modes of damaged truss model are adopted as the measurement data. The effectiveness of proposed method is verified through the numerical examples.

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Damage Detection of Truss Structures Using Extended Projection Filter (확장사영필터를 이용한 트러스 구조물의 손상 검출)

  • Suh, Ill-Gyo;Lim, Eun-Ji
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.9 no.4
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    • pp.195-201
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    • 2005
  • In this paper, a study of damage measures for truss structures using the Extended Projection filter theory is presented. Many researchers are interested in inverse problems and one of solution procedures for inverse problems that are very effective is the approach using the filtering algorithm in conjunction with numerical solution methods. In this paper, the projection filtering in conjunction with structural analysis is applied to the identification of damages in truss structures. And, the effectiveness of proposed method is verified through the numerical examples of a free vibrating structure.

Damage Detection of Truss Structures Using Nonlinear Parametric Projection Filter (비선형 파라메트릭 사영필터에 의한 트러스 구조물의 손상 검출)

  • Mun, Hyo-Jun;Suh, Ill-Gyo
    • Journal of the Korean Association for Spatial Structures
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    • v.4 no.2
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    • pp.73-80
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    • 2004
  • In this paper, a study of damage detection for 2-Dimensional Truss Structures using the parametric projection filter theorr is presented. Many researchers are interested in inverse problem and one of solution procedures for inverse problems that are very effective is the approach using the filtering algorithm in conjunction with numerical solution methods. In filtering algorithm, the Kalman filtering algorithm is well known and have been applied to many kind of inverse problems. In this paper, the Parametric projection filtering in conjunction with structural analysis is applied to the identification of damages in 2-D truss structures. The natural frequency and modes of damaged truss model are adopted as the measurement data. The effectiveness of proposed method is verified through the numerical examples.

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Economic Dispatch of Thermal Units of a GENCO Using the Gradient Projection Method (경사 투영법을 이용한 발전사업자의 경제급전)

  • 정정원
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.52 no.9
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    • pp.550-556
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    • 2003
  • Price-based unit commitment is one of bidding strategies which a Genco may take in a practical manner. For that purpose, it is required for a Genco to decide output levels of its generators at each trade period. In this paper, an economic dispatch of thermal units is proposed considering the quantity of reserve contracts. A gradient projection algorithm is adopted as an optimization tool. A direct form of a projection matrix without any calculation of matrix inverse and multiplications is induced. Besides, it is proved that there is no need to check one of the two optimality conditions in the gradient projection method, which also requires matrix inverse and multiplications.

A dynamic analysis for constrained multibody systems using pseudo-inverse and projection matrix (준역행렬과 투영행렬을 이용한 구속 다물체계의 동역학 해석)

  • Kim, Oe-Jo;Yoo, Wan-Suk
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.22 no.1
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    • pp.170-176
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    • 1998
  • In this paper, the column space and null space of the Jacobian matrix were obtained by using the pseudo-inverse method and projection matrix. The equations of motion of the system were replaced by independent acceleration components using the null space matrix. The proposed method has the following advantages. (1) It is simple to derive the null space. (2) The efficiency is improved by getting rid of constrained force terms. (3) Neither null space updating nor coordinate partitioning method is required. The suggested algorithm is applied to a three-dimensional vehicle model to show the efficiency.

EIT imaging with the projection filter

  • Kim, Bong-Seok;Kim, Min-Chan;Kim, Sin;Kim, Kyung-Youn
    • 제어로봇시스템학회:학술대회논문집
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    • pp.396-401
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    • 2003
  • Electrical impedance tomography(EIT) is a relatively new imaging modality in which the internal impedivity distribution is reconstructed based on the known sets of injected currents and measured voltages on the surface of the object. In this paper, an effective dynamic EIT imaging scheme is presented based on the projection filtering to estimate the unknown resistivity distribution. In particular, pre-integration (pre-grouping) technique is employed to stabilize the inverse algorithm. We carried out computer simulations with synthetic data to illustrate the reconstruction performance of the proposed algorithm.

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Estimation of a mixed-mode cohesive law for an interface crack between dissimilar materials

  • Song, Sung-Il;Kim, Kwang-Soo;Kim, Hyun-Gyu
    • Multiscale and Multiphysics Mechanics
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    • v.1 no.1
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    • pp.35-51
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    • 2016
  • In this paper, a mixed-mode cohesive law for an interface crack between epoxy and TR (transparent thermoplastic) resin is inversely estimated by the field projection method using numerical solutions and experimentally measured displacements. Displacements in a region far away from the crack tip are measured by digital image correlation technique. An inverse analysis, the field projection method formulated from the interaction J- and M-integrals with numerical auxiliary fields, is carried out to estimate a mixed-mode cohesive law for an interface crack between dissimilar materials. In the present approach, nonlinear deformations and damage near the crack tip are converted into the relationships of tractions and separations on crack surfaces behind the crack tip. The phase angle of mixed-mode singularities of the interface crack is also obtained from measured displacements in this study.

Performance Improvement of Stereo Acoustic Echo Canceller Using MINT Filtering (MINT 필터링에 의한 스테레오 음향 반향 제거기의 성능 향상)

  • 차경환
    • The Journal of the Acoustical Society of Korea
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    • v.21 no.1
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    • pp.42-46
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    • 2002
  • In this paper, a new pre-processing algorithm is proposed to improve the performance of stereo acoustic echo canceller. The proposed algorithm has the improved performance by the estimation error reduction of filter coefficient using input signal which was reduced reverberation of room in the basis MINT (Mu1tip1e-input/output Inverse Theorem) filtering. For real stereo speech signal and real room impulse response the results of simulation, we showed that the proposed method could improved 3∼5 dB ERLE (Echo Return Loss Enhancement) regardless of NLMS (Normalized Least Mean Square) and Projection adaptive algorithm.