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 19 of 19 for “"Time-domain methods"”.
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Matrix-free time-domain methods for general electromagnetic analysis
… Among existing computational electromagnetic methods, the explicit finite-difference time-domain (FDTD) method is free of matrix solutions. However, it requires a structured orthogonal grid for space discretization. In this work, we develop a new time-domain method that naturally requires no …
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High resolution optical time domain methods for measuring strain
High-resolution optical time-domain methods applied to measuring strain in an optical fiber are discussed. The use of this optical time-domain fiber sensor for measuring quasi-distributed strain along a cantilevered beam is experimentally demonstrated. This is accomplished by segmenting the sensor …
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System identification of dynamic structural systems using continuous-time domain methods
… the use of existing system identification methods, and (2) develop new system identification methods, in order to evaluate both loading and structural modal parameters of ambient excited structures for which the load process is difficult to measure. An example is the case of offshore …
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Terahertz time domain methods for material characterization of layered dielectric media
Material characterization methods for layered dielectric media are highly sought after in many fields including nondestructive evaluation, structural health monitoring, security imaging, biological tissue inspection and agricultural and industrial quality assurance. On the other hand, the still …
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Modelling and analysis of nonlinear thermoacoustic systems using frequency and time domain methods
… to enable analysis both in the frequency and time domains. Starting from linear analysis, the stability of thermoacoustic networks is investigated, and the use of adjoint methods for understanding the role of the system's parameters on its stability is demonstrated. Then, a nonlinear analysis …
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Investigation of explicit finite-element time-domain methods and modeling of dispersive media and 3D high-speed circuits
In this dissertation, efficient time-domain domain decomposition algorithms are investigated, compared, and further enhanced, and a new domain decomposition method is proposed based on the knowledge of existing ones. First, several explicit domain decomposition methods, including the dual-field …
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Analysis of Electric Disturbances from the Static Frequency Converter of a Pumped Storage Station
… of the electric network is done by frequency domain and time domain methods. Time domain methods are also employed for the analysis of the commutation transient produced by the SFC operation. Finally, the simulation results are used to evaluate the impact of the SFC operation on the station …
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Fast time- and frequency-domain finite-element methods for electromagnetic analysis
<p>Fast electromagnetic analysis in time and frequency domain is of critical importance to the design of integrated circuits (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 …
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Full-wave analysis of metallic structures at optical frequencies
… effects are reviewed. Both the frequency-domain and time-domain methods for simulating the structures are discussed. The finite element method is applied to study the scattering from the metallic structures in the frequency domain. The simulation results are shown for two-dimensional …
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Finite difference techniques for body of revolution radar cross section
… include body of revolution finite-difference time-domain methods with both staircase and conformal grids, a hybrid FD-TD/geometrical optics method, and a body of revolution parabolic wave equation method. In addition, the use of the monostatic-bistatic equivalence principle is explored in …
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Improved dynamic stability using FACTS devices with phasor measurement feedback
… test system, and eigenvalue sensitivity and time-domain methods will be used to determine the optimal controller characteristics for the modeled FACTS device. Stability results will be verified using eigenvalue analysis and time simulation techniques.
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Adjoint-based monopole synthesis of sound sources with complex directivities
Numerical time domain methods are continuously improving and gain in importance in virtual acoustics. The accurate modeling of directive sound sources is a prerequisite for acoustical simulations. In contrast to frequency domain methods, the directivity pattern of sound sources cannot be …
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Automated Vehicle Detection and Classification using Acoustic and Seismic Signals
… an investigation into acoustic and seismic methods for achieving such a system specifically for commercial road vehicles. Accurate algorithms have been developed for recognition of moving vehicles using fusion of acoustic and seismic signals. It has been found that seismic signals are less …
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Methodologies for Transient Simulation of Hybrid Electromagnetic/Circuit Systems with Multiple Time Scales
… systems while exploiting the multiple time scales that are often present in the numerical simulation of such systems. Three distinct approaches are presented to expedite such a simulation process, with the common theme that the methodologies should allow for the ability to utilize …
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An attempt to quantify errors in the experimental modal analysis process
… to parameter estimation phase. Though time-domain methods are actively being investigated by many researchers and are in use, fast Fourier transform (FFT) methods, due to their speed and ease of implementation, are the most widely used in experimental modal analysis work. This work …
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Investigation of general-purpose computing on graphics processing units and its application to the finite element analysis of electromagnetic problems
… are applied on the traditional frequency domain finite element method (FEM), the element-level time-domain methods, and the nonlinear discontinuous Galerkin method. First, the assembly and the solution phases of the FEM are parallelized and mapped onto the granular GPU processors. …
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The application of advanced hydrodynamic analyses in ship design
… nonlinear wave-induced motions and loads in the time domain. Seakeeping analysis has traditionally been incorporated late in the design process, using parametrics and two-dimensional linear strip theory methods in the frequency domain. Model testing, due to its relative expense, is incorporated …
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Floquet-Wave-Based Analysis of Transient Scattering From Doubly Periodic Structures
… analyzed predominantly using finite difference time domain methods. Unfortunately, for obliquely excited periodic structures, these solvers call for future field values to update current ones, and therefore cannot be applied directly. Several avenues for tackling this problem have been …
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The initiation of action potentials and the passive electrical properties of identified snail neurones
… neurones structure. Furthermore, frequency and time domain methods for electrotonic parameter estimation were contrasted and frequency domain methods were shown to be less susceptible to error. Frequency domain methods were applied to the problem of estimating the electrotonic parameters of some …