• 제목/요약/키워드: Inverse problem

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신경회로망을 사용한 역운동학 해 (A solution to the inverse kinematic by using neural network)

  • 안덕환;이종용;양태규;이상효
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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    • pp.124-126
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    • 1989
  • Inverse kinematic problem is a crucial point for robot manipulator control. In this paper, to implement the Jacobian control technique we used the Hopfield(Tank)'s neural network. The states of neurons represent joint veocities, and the connection weights are determined from the current value of the Jacobian matrix. The network energy function is constructed so that its minimum corresponds to the minimum least square error. At each sampling time, connection weights and neuron states are updated according to current joint position. Inverse kinematic solution to the planar redundant manipulator is solved by computer simulation.

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역분석에 의한 충격력 재현 특성 (Reconstruction Characteristics of Impact Force by Inverse Analysis)

  • 조창기;이규섭;류봉조;이종원
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1997년도 춘계학술대회 논문집
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    • pp.640-644
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    • 1997
  • This poaper descibes a method for reconstructing the impact force by inverse analysis. The inverse problem of reconstructing the impact force using experimentally measured structural responses tends to be ill-conditioned. In practical application, impact response data involve niise caused by the measurement system. We present a method to minimize the mean square error of reconstructed forcd. The agreement is very satisfactory in all the comparisons. This verifies the proposed method.

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열전도의 역문제 방법을 이용한 대형 LPG 엔진 피스톤의 열부하 해석 (Analysis of Thermal Loading of a Large LPG Engine Piston Using the Inverse Heat Conduction Method)

  • 박철우;이부윤
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2006년도 정기 학술대회 논문집
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    • pp.820-827
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    • 2006
  • The convection heat transfer coefficients on the top surface of a large liquid petroleum liquid injection(LPLi) engine piston are analyzed by solving an inverse thermal conduction problem. The heat transfer coefficients are numerically found so that the difference between analyzed temperatures from the finite element method and measured temperatures is minimized. Using the resulting heat transfer coefficients as the boundary condition, temperature of a large LPLi engine piston is analyzed.

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SOME INVERSE RESULTS OF SUMSETS

  • Tang, Min;Xing, Yun
    • 대한수학회보
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    • 제58권2호
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    • pp.305-313
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    • 2021
  • Let h ≥ 2 and A = {a0, a1, …, ak-1} be a finite set of integers. It is well-known that |hA| = hk - h + 1 if and only if A is a k-term arithmetic progression. In this paper, we give some nontrivial inverse results of the sets A with some extremal the cardinalities of hA.

THOMAS ALGORITHMS FOR SYSTEMS OF FOURTH-ORDER FINITE DIFFERENCE METHODS

  • Bak, Soyoon;Kim, Philsu;Park, Sangbeom
    • 대한수학회지
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    • 제59권5호
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    • pp.891-909
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    • 2022
  • The main objective of this paper is to develop a concrete inverse formula of the system induced by the fourth-order finite difference method for two-point boundary value problems with Robin boundary conditions. This inverse formula facilitates to make a fast algorithm for solving the problems. Our numerical results show the efficiency and accuracy of the proposed method, which is implemented by the Thomas algorithm.

RPSO 알고리즘을 이용한 벽면 방사율 추정에 관한 연구 (A Study on Wall Emissivity Estimation using RPSO Algorithm)

  • 이균호;백승욱;김기완;김만영
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2007년도 춘계학술대회B
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    • pp.2476-2481
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    • 2007
  • An inverse radiation analysis is presented for the estimation of the wall emissivities for an absorbing, emitting, and scattering media with diffusely emitting and reflecting opaque boundaries. In this study, a repulsive particle swarm optimization(RPSO) algorithm which is a relatively recent heuristic search method is proposed as an effective method for improving the search efficiency for unknown parameters. To verify the performance of the proposed RPSO algorithm, it is compared with a basic particle swarm optimization(PSO) algorithm and a hybrid genetic algorithm(HGA) for the inverse radiation problem with estimating the wall emissivities in a two-dimensional irregular medium when the measured temperatures are given at only four data positions. A finite-volume method is applied to solve the radiative transfer equation of a direct problem to obtain measured temperatures.

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Damage assessment of beams from changes in natural frequencies using ant colony optimization

  • Majumdar, Aditi;De, Ambar;Maity, Damodar;Maiti, Dipak Kumar
    • Structural Engineering and Mechanics
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    • 제45권3호
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    • pp.391-410
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    • 2013
  • A numerical method is presented here to detect and assess structural damages from changes in natural frequencies using Ant Colony Optimization (ACO) algorithm. It is possible to formulate the inverse problem in terms of optimization and then to utilize a solution technique employing ACO to assess the damage/damages of structures using natural frequencies. The laboratory tested data has been used to verify the proposed algorithm. The study indicates the potentiality of the developed code to solve a wide range of inverse identification problems in a systematic manner. The developed code is used to assess damages of beam like structures using a first few natural frequencies. The outcomes of the simulated results show that the developed method can detect and estimate the amount of damages with satisfactory precision.

Preclinical Prototype Development of a Microwave Tomography System for Breast Cancer Detection

  • Son, Seong-Ho;Simonov, Nikolai;Kim, Hyuk-Je;Lee, Jong-Moon;Jeon, Soon-Ik
    • ETRI Journal
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    • 제32권6호
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    • pp.901-910
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    • 2010
  • As a supplement to X-ray mammography, microwave imaging is a new and promising technique for breast cancer detection. Through solving the nonlinear inverse scattering problem, microwave tomography (MT) creates images from measured signals using antennas. In this paper, we describe a developed MT system and an iterative Gauss-Newton algorithm. At each iteration, this algorithm determines the updated values by solving the set of normal equations using Tikhonov regularization. Some examples of successful image reconstruction are presented.

Bayesian One-Sided Hypothesis Testing for Shape Parameter in Inverse Gaussian Distribution

  • Kang, Sang-Gil;Kim, Dal-Ho;Lee, Woo-Dong
    • Journal of the Korean Data and Information Science Society
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    • 제19권3호
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    • pp.995-1006
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    • 2008
  • This article deals with the one-sided hypothesis testing problem in inverse Gaussian distribution. We propose Bayesian hypothesis testing procedures for the one-sided hypotheses of the shape parameter under the noninformative prior. The noninformative prior is usually improper which yields a calibration problem that makes the Bayes factor to be defined up to a multiplicative constant. So we propose the objective Bayesian hypothesis testing procedures based on the fractional Bayes factor, the median intrinsic Bayes factor and the encompassing intrinsic Bayes factor under the reference prior. Simulation study and a real data example are provided.

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SIMPLIFIED TIKHONOV REGULARIZATION FOR TWO KINDS OF PARABOLIC EQUATIONS

  • Jing, Li;Fang, Wang
    • 대한수학회지
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    • 제48권2호
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    • pp.311-327
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    • 2011
  • This paper is devoted to simplified Tikhonov regularization for two kinds of parabolic equations, i.e., a sideways parabolic equation, and a two-dimensional inverse heat conduction problem. The measured data are assumed to be known approximately. We concentrate on the convergence rates of the simplified Tikhonov approximation of u(x, t) and its derivative $u_x$(x, t) of sideways parabolic equations at 0 $\leq$ x < 1, and that of two-dimensional inverse heat conduction problem at 0 < x $\leq$ 1, respectively.