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<td><img alt="Dissertation Defense Announcement at the Cullen College of Engineering" width="600" height="174" src="https://www.egr.uh.edu/sites/www.egr.uh.edu/files/enews/2022/images/thesis1.png">
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<strong>Physics Information Machine Learning For Time Domain Electromagnetic Simulation<br>
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<div style="font-size:18px;margin-bottom:5px" class="elementToProof"><strong>Yawei Su</strong></div>
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07/27/2022; 2:00PM-4:00PM (CST)<br>
Location: ECE Large Conference Room<br>
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<strong>Committee Chair:</strong><br>
Dr. Jiefu Chen<br>
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<strong>Committee Members:</strong><br>
Dr. Xuqing Wu | Dr. David R. Jackson</p>
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<strong>Abstract</strong></p>
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Neural Network has been widely used in all fields of research and has achieved great success. Physics Informed Neural Works (PINNs) is an import and relatively new attempt among deep neural network applications. PINN relays on the universal approximation theorem
and aims at solving physics differential equations, providing an alternative way to solve physics problems apart from conventional numerical simulation methods like Finite-difference Time-Domain (FDTD) method or Finite Element Analysis (FEA), turning the solving
of equations to an optimization process. In this thesis paper, I follow the previous work of Pan Zhang which tests PINN on several time-domain electromagnetic simulation examples and I concentrate on a simple 1-dimension electromagnetic cavity model with isotropic
and homogeneous media and extend the training time range to test the PINN performance on larger time scale problem. We do find PINN shows less probability to converge to an expected physical solution with time scale gets larger and finally fails to give any
meaningful result, which is known as the `spectrum bias'. To investigate this failure, we firstly define a parameter `Threshold Period Number' (TPN) and change the PINN parameters to see how these value influence the TPN. Then we change and improve the PINN
structure, trying to avoid the failure for larger time scale problem. We also visualize the PINN training process to help us analysis the problem. Although we still can not totally settle the spectrum bias, we find out some preliminary method to practically
increase TPN and get better result within certain time scale.</p>
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<td><img alt="Engineered For What's Next" width="600" height="82" src="https://www.egr.uh.edu/sites/www.egr.uh.edu/files/enews/2022/images/dissertation2.png"></td>
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