Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 36 for “"System Matrix"”.
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Optimum Semi-Iterative Methods for the Solution of Any Linear Algebraic System With a Square Matrix
… the iterative solution of a non-symmetric linear system, Ax = b, when the eigenvalues have positive real parts. The iterative parameters are reciprocals of the roots of a scaled and translated Chebyshev polynomial and depend upon an ellipse enclosing the spectrum of the system matrix.
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Improved approaches to the indirect force determination problems via experimental modal analysis
… problem, finding the applied forces knowing the system characteristics and the response, has been a difficult problem in structural dynamics. Insufficient accuracy in the system identification and uncorrelated content in the response exacerbate the ill-conditioned nature of the …
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Fast time- and frequency-domain finite-element methods for electromagnetic analysis
… (IC) and other advanced engineering products and systems. Many IC structures constitute a very large scale problem in modeling and simulation, the size of which also continuously grows with the advancement of the processing technology. This results in numerical problems beyond the reach of …
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Application of the time-domain finite-element method to analysis of 3D electric machine problems
… introduced to ameliorate the condition of the system matrix. The effects of the material parameters and the RCM algorithm on the system matrix condition are analyzed. Also, the tree-cotree splitting (TCS) technique is applied to solve low-frequency problems. Several examples are simulated and …
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Development of Spect and Ct Tomographic Image Reconstruction
… of fully three-dimensional voxel-based system matrix in parallel-beam, fan-beam, and cone-beam collimator geometries while modeling the process of attenuation, system resolution and sensitivity. This is achieved by casting rays through a volume of voxels and using ray-voxel intersection …
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Finite-Difference Methods for the Wave Equation with Reduced Dispersion Errors
… 2D and 3D. In our work, we will prove that the system for coefficients of these new schemes is solvable for any normalized wavenumbers up to the Nyquist. We will also look at the system matrix and prove that we can get higher order approximation to the dispersion at arbitrary normalized …
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The Reconstruction of Binary Images in Discrete Tomography by Using the Binary Steering Scheme
… methods for solving an underdetermined linear system Ax = b. Three algorithms: Algebraic Reconstruction Technique (ART) Algorithm, Cimmino's Algorithm (CIM) with Equal Weights Algorithm and Fully-Simultaneous Diagonally-Relaxed Orthogonal Projections (DROP) Algorithm are modified. We develop an …
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Time-stable high-order finite difference methods for overset grids
… is used and an eigenvalue analysis of the system matrix is performed to establish time-stability. The eigenvalue analysis approach for proving stability fails when the system matrix is not of a block triangular structure; therefore, we investigate the second case of the method where a …
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State-space LQG self-tuning control of flexible structures
… and are estimated recursively together with the system state that is needed for feedback. Also, the feedback gains are designed in the LQ framework based upon the estimated model parameters. Two problems concerning the uncertainty of model parameters are recognized. First, we consider the …
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Distortion correction in magnetic resonance imaging using the simulated point spread function
… well-suited to parallel implementation, as the system matrix used is sparse.
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Dynamics of power systems at critical load levels
… low frequency oscillations in large scale power systems have been explained in terms of commonly understood iterative schemes. These algorithms have been extended to include the calculation of any desired system mode. Next, the voltage instability problem has been addressed from a dynamic …
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Preconditioning of Karush--Kuhn--Tucker Systems arising in Optimal Control Problems
… of preconditioners for indefinite linear systems. The systems under investigation arise in the numerical solution of quadratic programming problems, for example in the form of Karush--Kuhn--Tucker (KKT) optimality conditions or in interior--point methods. Therefore, the system matrix is …
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Distributed online algorithms for energy management in smart grids
… The problems are modeled as discrete dynamic systems to investigate the stability and convergence of the algorithm. The update procedures are designed such that the iterates converge to the optimal solution of the original optimization problem, steered by the gain parameter corresponding to …
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Continuous-time multivariable system identification
… identification of continuous-time multivariable systems. Direct methods of identification, i.e. identifying a continuous-time model directly from samples of input-output data, are considered briefly. Of primary consideration is the indirect method of identification, which can be considered as a …
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Parameter Informed Reinforcement Learning for Vehicle System Identification
<p>Accurate system identification is essential for modeling and controlling vehicle dynamics. This dissertation explores the application of Parameter Informed Reinforcement Learning (PIRL) as a novel approach to system identification (SYSID). PIRL integrates prior system knowledge, such as physical …
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Boundary conditions for the solution of open-region electromagnetic scattering problems
… significant degradation of the sparsity of the system matrix. Finally, a systematic finite element method is developed for the purpose of solving a class of unbounded geometries, including inhomogeneously filled cavities or troughs. Numerical results are presented to show the validity and …
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OpenMP-CUDA implementation of the moment method and multilevel fast multipole algorithm on multi-GPU computing systems
… the multi-GPU parallelization of system matrix assembly, iterative solution, and fast evaluation of radar cross section (RCS) are discussed in detail. The parallel efficiency versus number of devices is investigated through the calculation of a conducting sphere on different number …
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Some issues in the sliding mode control of rigid robotic manipulators
… scheme, the parameters of the upper bound of system uncertainty are adaptively estimated. The controller estimates are then used as controller parameters to eliminate the effects of system uncertainty and guarantee asymptotic error convergence. • A decentralised adaptive sliding mode control …
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Model-order reduction techniques for the numerical solution of electromagnetic wave scattering problems
… the parameter-dependent behaviour of the system over the entire parameter range. This thesis focus is to implement robust, fast and accurate MOR techniques with strict error controls, for application with varying parameters, using the EFIE formulations. While these formulations result in …
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Accuracy improvement of the second-kind Fredholm integral equations in computational electromagnetics
… the near-singularities in the evaluation of the system matrix elements carefully. The extinction theorem is applied for accurate evaluation of the numerical errors in the calculation of scattering problems for generally shaped objects. Several examples are given to investigate and demonstrate the …
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