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 Title
 Application of MoM: Scattering calculations using condition number.
 Creator
 Zhuang, Zhijun., Florida Atlantic University, Bagby, Jonathan S., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
 Abstract/Description

Computational accuracy is widely recognized as a critical issue in applied electromagnetics. Increasing computational power is being applied to solve more complex electromagnetic systems with an emphasis on computational accuracy. The work of this thesis is focused on the implementation of Method of Moments (MoM) to integral equation formulations. The goal of this effort is to use what is known as condition number, and, a heuristic ruleofthumb is applied to investigate the computational...
Show moreComputational accuracy is widely recognized as a critical issue in applied electromagnetics. Increasing computational power is being applied to solve more complex electromagnetic systems with an emphasis on computational accuracy. The work of this thesis is focused on the implementation of Method of Moments (MoM) to integral equation formulations. The goal of this effort is to use what is known as condition number, and, a heuristic ruleofthumb is applied to investigate the computational accuracy of MoM in numerical electromagnetics. Other possible applications of condition number of the MoM matrix are also indicated.
Show less  Date Issued
 1999
 PURL
 http://purl.flvc.org/fcla/dt/15719
 Subject Headings
 Electromagnetism, Moments method (Statistics), Electromagnetic theory, Integral equationsNumerical solutions
 Format
 Document (PDF)
 Title
 Determination of probability density from statistical moments by neural network approach.
 Creator
 Zheng, Zhiyin., Florida Atlantic University, Cai, GuoQiang, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

It is known that response probability densities, although important in failure analysis, are seldom achievable for stochastically excited systems except for linear systems under additive excitations of Gaussian processes. Most often, statistical moments are obtainable analytically or experimentally. It is proposed in this thesis to determine the probability density from the known statistical moments using artificial neural networks. A multilayered feedforward type of neural networks with...
Show moreIt is known that response probability densities, although important in failure analysis, are seldom achievable for stochastically excited systems except for linear systems under additive excitations of Gaussian processes. Most often, statistical moments are obtainable analytically or experimentally. It is proposed in this thesis to determine the probability density from the known statistical moments using artificial neural networks. A multilayered feedforward type of neural networks with error backpropagation training algorithm is proposed for the purpose and the parametric method is adopted for identifying the probability density function. Three examples are given to illustrate the applicability of the approach. All three examples show that the neural network approach gives quite accurate results in comparison with either the exact or simulation ones.
Show less  Date Issued
 1996
 PURL
 http://purl.flvc.org/fcla/dt/15330
 Subject Headings
 Distribution (Probability theory), Moments method (Statistics), Estimation theory, Structural failuresInvestigation, Neural networks (Computer science)
 Format
 Document (PDF)
 Title
 An electromagnetic code evaluation in the 100 MHz to 1000 MHz region.
 Creator
 Casciato, Mark D., Florida Atlantic University, Helmken, Henry
 Abstract/Description

For certain wavelength size objects, the frequency range between 100 MHz and 1000 MHz spans a transition region when using low frequency electromagnetic scattering codes based on Method of Moments (MoM) to high frequency codes based on Physical Theory of Diffraction (PTD) and ray tracing techniques. As the wavelength size of the object increased, MoM codes can require prohibitively long computational times and hence the more approximate high frequency codes become more attractive. The Ohio...
Show moreFor certain wavelength size objects, the frequency range between 100 MHz and 1000 MHz spans a transition region when using low frequency electromagnetic scattering codes based on Method of Moments (MoM) to high frequency codes based on Physical Theory of Diffraction (PTD) and ray tracing techniques. As the wavelength size of the object increased, MoM codes can require prohibitively long computational times and hence the more approximate high frequency codes become more attractive. The Ohio State Material Wire code (MATWRS) was selected as a representative MoM code for characterizing the transition region. XPATCH was selected as a representative high frequency code with ACAD used as the general modeling program. To evaluate these codes, a comparison of Radar Cross Section (RCS) predictions for simple PEC canonical shapes was made. Comparisons were made to both measured data where available and predictions generated by the McDonnell Douglas Body of Revolution (BOR) code.
Show less  Date Issued
 1995
 PURL
 http://purl.flvc.org/fcla/dt/15191
 Subject Headings
 Computeraided design, Radar cross sections, Electromagnetic waves, Moments method (Statistics)
 Format
 Document (PDF)