Digital Commons Network^™

Versatile And Robust Non-Iterative Coupling Algorithm For Vehicle-Structure Interaction, Arya Datta

Theses and Dissertations

The dynamic analysis of the vehicle-structure interactions can be extremely computationally expensive. A general non-iterative coupling algorithm based on the substructure approach has been presented. It retains the advantage of the substructure approach that smaller subsystems are solved instead of a large system, which is usually solved when monolithic systems are solved. However, the advantage of using this general coupling approach is that it is non-iterative in nature, instead of the substructure approach that usually uses iterative procedure. The general coupling algorithm developed has been implemented to analyze dynamic interactions between the vehicle and the structure, both in two and …

Efficient Photonic Integrated Circuits – Optimizing Fiber-To-Chip Coupling, Modulation, And Detection, Peichuan Yin

Theses

Photonic integrated circuits (PICs) are attracting attention in a wide range of applications due to their superior performance over traditional discrete photonic devices. However, the development of PICs is bottlenecked by the integration of different fundamental building blocks. High sensitivity and diverse material properties hinder the realization of a monolithic photonic integrated circuit platform. High-efficiency solutions for photonic device integration are critical for making high-performance and low-cost devices. The objective of this work is to demonstrate high-efficiency optimization methods for a comprehensive photonic integrated chip system. This work analyzes the transition of optical signal waves between each component in a …

Quantifying Intra- And Interlimb Use During Unimanual And Bimanual Tasks In Persons With Hemiparesis Post-Stroke, Susan V. Duff, Aaron Miller, Lori Quinn, Gregory Youdan Jr., Lauri Bishop, Heather Ruthrauff, Eric Wade

Physical Therapy Faculty Articles and Research

Background

Individuals with hemiparesis post-stroke often have difficulty with tasks requiring upper extremity (UE) intra- and interlimb use, yet methods to quantify both are limited.

Objective

To develop a quantitative yet sensitive method to identify distinct features of UE intra- and interlimb use during task performance.

Methods

Twenty adults post-stroke and 20 controls wore five inertial sensors (wrists, upper arms, sternum) during 12 seated UE tasks. Three sensor modalities (acceleration, angular rate of change, orientation) were examined for three metrics (peak to peak amplitude, time, and frequency). To allow for comparison between sensor data, the resultant values were combined into …

Design Of Wideband Decoupling Networks For Mimo Antennas Based On An N-Ary Optimization Algorithm, Min Li, Kwan Lawrence Yeung, Lijun Jiang, Ross Murch

Electrical and Computer Engineering Faculty Research & Creative Works

Techniques for reducing the coupling between antenna elements in multiple-input multiple-output (MIMO) systems are important for achieving the full potential of MIMO. In this article, a general and systematic method is developed to design a wideband decoupling and matching network (DMN) for MIMO antenna arrays. The DMN is formed by grid-like transmission lines interconnected by lumped components, whose reactance can be obtained from an N-ary optimization algorithm. Four design benchmarks are performed for validating decoupling methodology, elaborating on design/implementation procedure, and demonstrating superiority of the proposed method. Results show that the DMN achieves broad isolation bandwidth while occupying a small …

Some Improved Markov Chain Convergence Rates, Fun Choi John Chan

All Dissertations

Explicit convergence rates to equilibrium are established for non reversible Markov chains not having an atom via coupling methods. We consider two Markov chains having the same transition function but different initial conditions on the same probability space, that is, a coupling. A random time is constructed so that subsequent to the random time the two processes are identical. Exploiting a shadowing condition, we show that it is possible to bound the tail distribution of the random time using only one of the chains. This bound gives the convergence rate to equilibrium for the Markov chain. The method is then …

Novel Cma Scheme To Design Self-Decoupled Mimo Dipole Pair For Base-Station Applications, Min Li, Bing Xiao, Changfei Zhou, Di Wu, Kwan Lawrence Yeung, Lijun Jiang, Ross Murch

Electrical and Computer Engineering Faculty Research & Creative Works

This article presents a novel method to design multiple-input-multiple-output (MIMO) antennas based on characteristic mode analysis (CMA), which is different from using individual excitation of each characteristic mode for high isolation. The CMA is performed to design a pair of symmetric slots on two connected dipole antennas (a MIMO dipole pair), so that two desired characteristic modes can be generated at the same frequency, one of which is in common mode and the other in differential mode. Hence, when one antenna element is excited, the two characteristic modes combine and cancel each other at the other antenna element, leading to …

The Role Of Slow Slip Events In The Cascadia Subduction Zone Earthquake Cycle, Juliette P. Saux, Elias G. Molitors Bergman, Eileen L. Evans, John P. Loveless

Geosciences: Faculty Publications

Slow slip events (SSEs) detected on the Cascadia Subduction Zone interface at 30–50 km depth imply a release of accumulated strain. However, studies of interseismic deformation in Cascadia typically find coupling on the upper 30 km of the interface, which is generally accepted as defining the seismogenic zone. Estimates of coupling using net interseismic velocities (including SSE effects) and restricting coupling to the shallow interface may underestimate slip deficit accumulation at depths >30 km. Here, we detect reversals in GPS motion as indications of SSEs, then use SSE displacements to estimate cumulative slow slip from 2007 to 2021. We calculate …

Photophysics Of Metalloporphyrins Strongly Coupled To Cavity Photons, Aleksandr Avramenko

Wayne State University Dissertations

This dissertation will discuss the photophysics of metalloporphyrins, mainly CuTPP, ZnTPP, and H2TPP under strong light-matter coupling conditions. Strong light-matter coupling was achieved by embedding the previously mentioned chromophores into a spun coated PMMA polymer coating which is then incorporated as a spacer layer in a FabryPérot nano-cavity. The cavity thickness is chosen so that the cavity photon is of similar energy as the B, or Soret transition (2nd excited state) of the porphyrin molecule. The exchange of energy between the cavity photon and the molecular mode leads to the formation of polariton states.

Increasing the concentration of the molecules …

De-Embedding For Coupled Three-Port Devices, Yuandong Guo, Bo Pu, Donghyun Kim, Jun Fan

Electrical and Computer Engineering Faculty Research & Creative Works

In many applications, the device under test (DUT) is embedded into a test setup. Various de-embedding techniques have been proposed to expose the real electrical behaviors of a DUT, e.g., the traditional thru-reflect-line and short-open-load-thru algorithms, where the T-matrix and its inverse form are adopted in the mathematical process. In the fields of radiofrequency and electromagnetic compatibility, a DUT may have three coupled ports, and the symmetry in the associated S-matrix breaks down, because the numbers of entry and exist ports are not equal, which results in a non-square T-matrix based upon the definitions. Given that the inverse expression of …

A General Coupling Methodology For Unsteady Aerostructural Optimization With Analytic Derivatives, Taylor Mcdonnell, Adam Cardoza, Denis-Gabriel Caprace, Andrew Ning

Faculty Publications

Multidisciplinary design optimization offers a comprehensive approach for designing complex aerostructural systems such as wind turbines. Gradient-based multidisciplinary design optimization can be used to optimize complex systems using large numbers of design variables. However, the convergence of gradient-based optimization methods to an optimal solution is highly dependent on the accuracy of the provided derivatives. In this paper, we propose a general method for creating unsteady coupled systems for steady-state, eigenvalue, and time-domain analyses. We then describe how highly accurate derivatives may be obtained from these analyses using a combination of automatic differentiation and analytic methods (including the unsteady adjoint). Finally, …

Dual-Band Decoupling Network For Mimo Antennas, Min Li, Lijun Jiang, Kwan Lawrence Yeung

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a novel method to design a decoupling network (DN) to increase isolation between dual-band antennas. The DN design is based on the scattering matrix and optimized by the Genetic Algorithm (GA). The decoupling example shows that the DN offers impedance matching and high isolation within desired bands, verifying the concept.

A Fast Cascading Method For Predicting The Coupling From External Plane Waves To Pcbs, Shengxuan Xia, James Hunter, Aaron Harmon, Mohamed Z.M. Hamdalla, Ahmed M. Hassan, Chulsoon Hwang, Victor Khilkevich, Daryl G. Beetner

Electrical and Computer Engineering Faculty Research & Creative Works

The radio frequency (RF) coupling to electronic devices impacts their EMC performance. The functionalities of a working electronic device may be disrupted when the electromagnetic (EM) coupling reaches a certain level. Studies of the EM coupling to printed circuit boards (PCBs) are therefore essential for RF susceptibility and EMC purposes. For decades, researchers focused on the analytical modeling of EM coupling to transmission lines. However, when it comes to more realistic PCBs the analysis usually still relies heavily on full-wave simulations because of the complexity of the structures and the lack of analytical solutions. Using a traditional full-wave modeling approach, …