This paper presents a finite element plasticity-based computer algorithm to analyze steel frames with flexible joints under static proportional loading, unloading, and reverse loading. Each connection mechanism is mod...
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This paper presents a finite element plasticity-based computer algorithm to analyze steel frames with flexible joints under static proportional loading, unloading, and reverse loading. Each connection mechanism is modeled using a rotational spring element with two nodes of identical spatial coordinates and the same translational degrees of freedom and different rotational degrees of freedom for modeling the relative rotation of the beam and ends of the connection. Instead of using a classical coupled nonlinear algorithm for the connection element and member geometric stiffness, a unique solution method is introduced that simultaneously iterates to find the incremental connection element and member geometric stiffness of the structure through solving the nonlinear system equation. To model unloading and reverse loading at the joints between beams and columns, a three-parameter, kinematics hardening model for moment-rotation behavior is considered. For proof-of-concept, a one-story, one-bay frame with two connections is considered for parametric study. It is shown that different connection constitutive equation (moment-rotation characteristic) in a frame could cause moment reversal in some connection(s).
Impulsive noise is an important challenge for the practical implementation of active noise control (ANC) systems. The advantages and disadvantages of popular filtered-X least mean square (FXLMS) ANC algorithm and nonl...
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Impulsive noise is an important challenge for the practical implementation of active noise control (ANC) systems. The advantages and disadvantages of popular filtered-X least mean square (FXLMS) ANC algorithm and nonlinear filtered-X least mean M-estimate (FXLMM) algorithm are discussed in this paper. A new modified FXLMM algorithm is also proposed to achieve better performance in controlling impulsive noise. Computer simulations and experiments are carried out for all three algorithms and the results are presented and analyzed. The results show that the FXLMM and modified FXLMM algorithms are more robust in suppressing the adverse effect of sudden large amplitude impulses than FXLMS algorithm, and in particular, the proposed modified FXLMM algorithm can achieve better stability without sacrificing the performance of residual noise when encountering impulses. (C) 2012 Elsevier Ltd. All rights reserved.
In article the algorithm of numerical modelling of the nonlinear equation of Korteweg-de Vrieze which generates nonlinear algorithm of digital processing of signals is considered. For realisation of the specified algo...
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ISBN:
(纸本)9780819479136
In article the algorithm of numerical modelling of the nonlinear equation of Korteweg-de Vrieze which generates nonlinear algorithm of digital processing of signals is considered. For realisation of the specified algorithm it is offered to use a inverse scattering method (ISM). algorithms of direct and return spectral problems, and also problems of evolution of the spectral data are in detail considered. Results of modelling are resulted.
The control problem of double-link wheeled transport robot with three steering wheels is considered in kinematic approach. For this object the algorithms of program trajectory selection, the synthesis of stabilization...
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The control problem of double-link wheeled transport robot with three steering wheels is considered in kinematic approach. For this object the algorithms of program trajectory selection, the synthesis of stabilization system and synthesis of servosystem are offered. It is noted, that as a result of using the offered synthesis algorithms of stabilization system and servosystem there are obtained the true nonlinear algorithms. The good performance of these algorithms is not limited only by small initial deviations. To demonstrate the efficiency of the given approach some examples were considered.
The accurate magnetic localization and orientation technique has dramatically enhanced the applications of capsule endoscope for the gastrointestinal (GI) tract examination. Yet, the surgical robot has been hindered t...
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ISBN:
(纸本)9781424467129
The accurate magnetic localization and orientation technique has dramatically enhanced the applications of capsule endoscope for the gastrointestinal (GI) tract examination. Yet, the surgical robot has been hindered to use widely due to the limitations of current surgical navigation technique. In this paper, an electromagnetic navigation system based on coils and magnetic sensor is introduced. The coils perform as the excitation sources to create the variable magnetic field, and which is received by the magnetic sensor. The coupling between excitation sources and magnetic sensor can determine a set of equations which contain the 6-D parameters of position and orientation information. Then, the nonlinear algorithm is given to solve these equations, and the simulation results show that we can obtain acceptable accuracy of position and orientation through this method. In additional, the relationship between the SNR and the accuracy of position and orientation also be analyzed, at the minimum SNR level with 45dB, the average error of position and orientation are 1mm and 0.5 degrees.
This letter proposes a nonlinear L-1-norm approach for joint image registration and super-resolution (SR). Image SR is the fusion of multiple low-resolution (LR) images to produce a high-resolution (HR) image. Convent...
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This letter proposes a nonlinear L-1-norm approach for joint image registration and super-resolution (SR). Image SR is the fusion of multiple low-resolution (LR) images to produce a high-resolution (HR) image. Conventional SR algorithms are sensitive to the initial registration error and outliers in the LR images. In view of this, we present a new SR method to address these problems using L-1-norm optimization in joint image registration and HR image reconstruction. Experimental results show that the proposed method is effective in handling these issues in the HR image reconstruction.
The model of wheeled transport robot without a steering wheel, taking into account dynamic effects, is considered. The nonlinear algorithm of stabilizing the motion of such model is proposed. This algorithm is general...
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The model of wheeled transport robot without a steering wheel, taking into account dynamic effects, is considered. The nonlinear algorithm of stabilizing the motion of such model is proposed. This algorithm is generalized to the case of tracking the given program trajectory by the robot. The effectiveness of the proposed algorithms is illustrated by examples.
This article presents lighting and colorimetric characteristics of recently developed soffit low-power metal-halogen lamps (LPMHL) of colour radiation intended for decorative and architectural illumination. Characteri...
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This article presents lighting and colorimetric characteristics of recently developed soffit low-power metal-halogen lamps (LPMHL) of colour radiation intended for decorative and architectural illumination. Characteristics of the lamps, including colour purity and dominant wavelength, correspond to international standards. The results of light flux and colour purity control of these lamps are given using a reduction of the supply line voltage, in accordance with a nonlinear time algorithm, securing a protecting operation mode of the lamps and a direct saving of the electric power (up to 40%) in multiple lamp lighting installations.
Once image motion is accurately estimated, we can utilize those motion estimates for image sharpening and we can remove motion blurs. First, for the motion de-blurring, this paper presents a model-based PDE method tha...
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ISBN:
(纸本)0819459763
Once image motion is accurately estimated, we can utilize those motion estimates for image sharpening and we can remove motion blurs. First, for the motion de-blurring, this paper presents a model-based PDE method that minimizes the regularized energy functional defined with a spatially variant model of motion blurs. Unlike the case of spatially invariant image blurs, the minimization of the energy functional cannot be achieved in a closed non-iterative way, and we derive its iterative algorithm. The standard regularization method uses a square function to measure energy of its solution function, and employs the energy functional composed of the data-fidelity energy term to measure a deviation of a solution function from the assumed model of motion blurs and the regularization energy term to impose smoothness constraints on a solution function. However, the standard variational method is not proper for the motion de-blurring, because it is sensitive to model errors, and occurrence of errors are inevitable in motion estimation. To improve the robustness against the model errors, we employ a nonlinear robust estimation function for measuring energy to be minimized. Secondly, this paper experimentally compares the model-based PDE method with our previously presented model-free PDE method that does not need any accurate blur model. In the model-error-free case the model-based PDE method outperforms the model-free PDE method, whereas in the model-error case the latter works better than the former.
The aim of this paper is to discuss the problem of reconstructing surfaces from qualitative observations. The problem statement is motivated by examples from testing quality of materials. The proposed estimator is non...
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The aim of this paper is to discuss the problem of reconstructing surfaces from qualitative observations. The problem statement is motivated by examples from testing quality of materials. The proposed estimator is nonlinear and nonparametric. Its consistency is discussed and the rate of convergence is given. Then, we propose its smoothed and adaptive version and validate it using simulated data. (C) 2005 Published by Elsevier Ltd.
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