Engineering Commons^™

Schizophrenia Classification Using Resting State Eeg Functional Connectivity: Source Level Outperforms Sensor Level, Sima Azizi, Daniel B. Hier, Donald C. Wunsch

Chemistry Faculty Research & Creative Works

Disrupted Functional and Structural Connectivity Measures Have Been Used to Distinguish Schizophrenia Patients from Healthy Controls. Classification Methods based on Functional Connectivity Derived from EEG Signals Are Limited by the Volume Conduction Problem. Recorded Time Series at Scalp Electrodes Capture a Mixture of Common Sources Signals, Resulting in Spurious Connections. We Have Transformed Sensor Level Resting State EEG Times Series to Source Level EEG Signals Utilizing a Source Reconstruction Method. Functional Connectivity Networks Were Calculated by Computing Phase Lag Values between Brain Regions at Both the Sensor and Source Level. Brain Complex Network Analysis Was Used to Extract Features and …

Development And Characterization Of Nb₃N/Al₂0₃ Superconducting Multilayers For Particle Accelerators, Chris Sundahl, Junki Makita, Paul B. Welander, Yi-Feng Su, Fumitake Kametani, Lin Xie, Huimin Zhang, Lian Li, Alex Gurevich, Chang-Beom Eom

Physics Faculty Publications

Superconducting radio-frequency (SRF) resonator cavities provide extremely high quality factors > 10¹⁰ at 1-2 GHz and 2 K in large linear accelerators of high-energy particles. The maximum accelerating field of SRF cavities is limited by penetration of vortices into the superconductor. Present state-of-the-art Nb cavities can withstand up to 50 MV/m accelerating gradients and magnetic fields of 200-240 mT which destroy the low-dissipative Meissner state. Achieving higher accelerating gradients requires superconductors with higher thermodynamic critical fields, of which Nb₃Sn has emerged as a leading material for the next generation accelerators. To overcome the problem of low vortex penetration …

One-Dimensional Lateral Force Anisotropy At The Atomic Scale In Sliding Single Molecules On A Surface, Yuan Zhang, Daniel J. Trainer, Badri Narayanan, Yang Li, Anh T. Ngo, Sushila Khadka, Arnab Neogi, Brandon Fisher, Larry A. Curtiss, Subramanian K.R.S. Sankaranarayanan, Saw Wai Hla

Physics Faculty Publications

Using a q+ atomic force microscopy at low temperature, a sexiphenyl molecule is slid across an atomically flat Ag(111) surface along the direction parallel to its molecular axis and sideways to the axis. Despite identical contact area and underlying surface geometry, the lateral force required to move the molecule in the direction parallel to its molecular axis is found to be about half of that required to move it sideways. The origin of the lateral force anisotropy observed here is traced to the one-dimensional shape of the molecule, which is further confirmed by molecular dynamics simulations. We also demonstrate that …

Inverted Geometry Ceramic Insulators In High Voltage Dc Electron Guns For Accelerators, C. Hernandez-Garcia, G. Palacios-Serrano, P. Adderley, D. Bullard, J. Grames, Md. Abdullah Mamun, M. Poelker, M. Stutzman, R. Suleiman, Y. Wang, S.A.K. Wijethunga

Physics Faculty Publications

A direct current (dc) high voltage photo-emission electron gun operating at 130 kV is utilized at the Jefferson Lab (JLab) Continuous Electron Beam Accelerator Facility to generate spin-polarized electrons for nuclear physics experiments. Over the past decade, JLab has tested and implemented inverted-geometry ceramic insulators in photoguns, connecting the cathode electrode in vacuum to the high voltage power supply using commercial high voltage cables. The results of those tests showed that breakdown voltage was increased using triple-point shielding electrodes and bulk-doped insulators that allow charge drainage. This contribution describes ongoing work to develop a robust insulatorcable connector for reliably applying …

Magnetic Field Sensors For Detection Of Trapped Flux In Superconducting Radio Frequency Cavities, Ishwari Prasad Parajuli, Gianluigi Ciovati, Jean R. Delayen

Physics Faculty Publications

Superconducting radio frequency (SRF) cavities are fundamental building blocks of modern particle accelerators. They operate at liquid helium temperatures (2–4 K) to achieve very high quality factors (10¹⁰–10¹¹). Trapping of magnetic flux within the superconductor is a significant contribution to the residual RF losses, which limit the achievable quality factor. Suitable diagnostic tools are in high demand to understand the mechanisms of flux trapping in technical superconductors, and the fundamental components of such diagnostic tools are magnetic field sensors. We have studied the performance of commercially available Hall probes, anisotropic magnetoresistive sensors, and flux-gate magnetometers with …

A Kinetic Evaluation For Phenothiazine Base Copolymers, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

In here, the non-isothermal decomposition kinetics of co-polymers-based phenothiazine was present-ed. For this, firstly, 3, 7-di-2-thienyl-10H-phenothiazine (TF) was prepared via an optimized Suzu-ki–Miyaura cross-coupling reaction. After monomer (TF) characterization, the copolymerization re-actions with EDOT and thiophene were performed by the electrochemical technique. The molecular masses of the co-polymers were found by gel permeation chromatography (GPC) analysis. Thermal characterizations of the resulting polymers were conducted by thermogravimetric analyses. The thermal decomposition kinetics of the resulting polymers was also performed. For this, the kinetic methods (Tang, FWO, KAS, Kissinger, and Friedman) based on the multiple heating rates were used. Several kinetic parameters …

A Multi-Elm Model For Incomplete Data, Baichuan Chi, Amaury Lendasse, Edward Ratner, Renjie Hu

Engineering Management and Systems Engineering Faculty Research & Creative Works

This Paper Presents a Novel Model of Extreme Learning Machines (Elms) for Incomplete Data. Elms Are Fast Accurate Randomized Neural Networks. Nevertheless, Elm Can Only Be Applied on the Complete Dataset. Therefore, a Novel Multi-Elm Model for Incomplete Data is Proposed, Consisting of Multiple Secondary Elms and One Primary Elm. the Secondary Elms Are Approximating the Primary Elm's Hidden Neurons' Outputs for the Data with Missing Values. as Summarized in the Experimental Section, This Model Can Be Applied on Data with Any Missing Patterns, without using Imputations and Can Outperform the Traditional Imputation Methods within a Reasonable Fraction of Missing …

Hybrid Beamforming With Deep Learning For Large-Scale Antenna Arrays, Rentao Hu, Lijun Jiang, Ping Li

Electrical and Computer Engineering Faculty Research & Creative Works

The emergence of highly directional beamforming technology makes millimeter wave frequency band communication possible in future wireless communication networks. Based on the multipath characteristics of millimeter wave frequency communication, a high-precision multipath channel estimation algorithm based on signal subspace is proposed. In the mobile terminal, an iterative heuristic radiofrequency combination algorithm based on spatial points is proposed. The analog precoding at the base station uses deep learning to accelerate the calculation, and then the multi-user communication is modeled to design the digital precoding. The simulation results show that the multi-channel estimation algorithm can estimate 4 paths with an error of …

Changes In Cerebral Volume And White Matter Integrity In Adults On Hemodialysis And Relationship To Cognitive Function, W. T. Richerson, L. G. Umfleet, Brian D. Schmit, D. F. Wolfgram

Biomedical Engineering Faculty Research and Publications

Introduction: Patients on hemodialysis (HD) have a significant burden of cognitive impairment. Characterizing the cerebral structural changes in HD patients compared to healthy controls and evaluating the relationship of cerebral structural integrity with cognitive performance in HD patients can help clarify the pathophysiology of the cognitive impairment in HD patients. Methods: In this cross-sectional study, in-center HD patients ≥50 years of age underwent brain structural and diffusion MRIs and cognitive assessment using the NIH Toolbox cognition battery. The cerebral imaging measures of the HD participants were compared to imaging from age-matched controls. Gray matter volume, white matter volume, and white …

Design Of Dual-Band Decoupling Network For Two Antennas, Min Li, Lijun Jiang, Kwan Lawrence Yeung

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a dual-band decoupling network for two antennas. Design formulas are derived with systematic design procedures. Two benchmarks are presented to elaborate on the design procedure. Results show that the network offers impedance matching, high isolation, and high efficiency at both frequencies, verifying the proposed concept and theory.

Model Computation With Second-Order Radiative Transfer Equation For Snow Medium Using Coupled Finite Element Method And Method Of Moment And Relaxed Hierarchical Equivalent Source Algorithm, Hamsalekha A. Kumaresan, H. T. Ewe, Gobi Vetharatnam, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

Active microwave remote sensing is essential to monitor the conditions of the environment by analyzing the microwave returns from the earth terrain. Various Computational Electromagnetics (CEM) techniques are implemented to study the backscattering coefficient of numerous earth terrains such as vegetation and snow medium. In this paper, a theoretical model based on second order radiative transfer equation is investigated by incorporating two computational methods which are known as coupled Finite Element Method (FEM) and Method of Moment (MoM), and Relaxed Hierarchical Equivalent Source Algorithm (RHESA). These theoretical models consider three shapes of scatterers which can be used to represent the …

Review On Resistive Switching Mechanisms Of Bio-Organic Thin Film For Non-Volatile Memory Application, Kuan Yew Cheong, Ilias Ait Tayeb, Feng Zhao, Jafri Malin Abdullah

Electrical and Computer Engineering Faculty Research & Creative Works

Bio-organic, as one of the sustainable and bioresorbable materials, has been used as an active thin film in producing resistive switching random access memory (RRAM) due to its specialized properties. This type of nonvolatile memory consists of a simple unit structure with the processed and solidified bio-organic-based thin film sandwiched between two electrodes. Its memory characteristics are significantly affected by the resistive-switching mechanism. However, to date, the reported mechanisms are very diverse and scattered, and to our best knowledge, there is no literature that reviewed comprehensively the mechanisms of resistive switching in bio-organic-based thin films. Therefore, the objective of this …

Novel Transformer With Variable Leakage And Magnetizing Inductances, Angshuman Sharma, Jonathan W. Kimball

Electrical and Computer Engineering Faculty Research & Creative Works

This paper introduces the concept of a novel variable inductance transformer (VIT) whose leakage and magnetizing inductances can be varied dynamically and independently to aid the advancement of research in isolated power electronic converters. In this transformer, the leakage inductance can be varied by varying the length of overlap between the primary and secondary windings, while the magnetizing inductance can be varied by varying the air gap between the core legs. Individual controls for the two inductances ensure that one can be varied independent of the other, as needed to satisfy different power conversion objectives. In this paper, the analytical …

Small-And Large-Scale Strain Sensing Using Frequency Selective Surfaces, Swathi Muthyala Ramesh, Kristen M. Donnell

Electrical and Computer Engineering Faculty Research & Creative Works

Frequency selective surfaces (FSSs) are arrays of conductive elements or patches that have specific reflection and transmission responses. In this work, an FSS sensor designed to measure small (0% - 0.5%) and large (0% - 5%) scale strain is presented. The proposed unit cell of the sensor consists of two passive dipoles (of different dimensions) arranged normal to one another. This was done to reduce the error of small-scale strain on the large-scale strain measurement, and vice versa. Strain sensing is achieved by monitoring the change in the resonant frequencies of the two dipoles using an interrogating signal linearly polarized …

Multidimensional Extensions To Generalized Averaged Models For Multi-Frequency-Excited Dynamic Systems, Kartikeya Jayadurga Prasad Veeramraju, Jonathan W. Kimball

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a novel Harmonic Axis Decoupling (HAD) method is proposed for extending the capabilities of the Generalized Averaged Modeling (GAM) technique. The conventional GAM technique is first revisited, and the problems encountered in the multiplication of two Double Fourier Series (DFS) signals in the time domain are investigated. The method of translating Fourier vectors to Discrete Fourier Images (DFI) in the frequency plane is proposed, and the ramifications of this conversion on DFS product terms in the time domain are investigated. The two-dimensional DFI convolution technique resulting from HAD is used for the dynamic modeling of power converters …

Developing Optimal Energy Arbitrage Strategy For Energy Storage System Using Reinforcement Learning, Haotian Chen, Rui Bo, Waqas Ur Rehman

Electrical and Computer Engineering Faculty Research & Creative Works

This paper introduced a reinforcement learning based method for developing operational strategy for an energy storage system (ESS) to achieve energy arbitrage in a microgrid or power system. In comparison to conventional energy resources such as gas turbines units or wind plant, it is more challenging to design an optimal strategy for ESS because of their limited energy and the impact of future electricity prices. The energy arbitrage problem also presents unique challenges than the economic dispatch problem because the ESS owner has very limited information of the system compared to those available to grid operators. In this work, reinforcement …

Detection Of Gaussian Attacks In Power Systems Under A Scalable Kalman Consensus Filter Framework, Arnold Fernandes, Rui Bo, Jonathan W. Kimball, Bruce M. Mcmillin

Electrical and Computer Engineering Faculty Research & Creative Works

The dynamic non-linear state-space model of a power-system consisting of synchronous generators, buses, and static loads has been linearized and a linear measurement function has been considered. A distributed dynamic framework for estimating the state vector of the power system has been designed here. This framework employs a type of distributed Kalman filter (DKF) known as a Kalman consensus filter (KCF) which is located at distributed control centers (DCCs) that fuse locally available noise ridden measurements, state vector estimates of neighboring control centers, and a prediction obtained by the linearized model to obtain a filtered state vector estimate. Further, the …

Stochastic Edge Detection For Fine-Grained Progressive Precision, Youngwook Lee, Kyung Ki Kim, Yong Bin Kim, Minsu Choi

Electrical and Computer Engineering Faculty Research & Creative Works

Stochastic Computing (SC) is a method of performing an operation by expressing a probability in a bitstream. This format is simpler than the format of conventional binary computing and can be implemented in hardware with fewer resources. In addition, by using a Low-Discrepancy (LD) sequence, faster convergence can be derived. This paper shows the experimental results of applying SC using LD sequence to edge detection algorithms including Sobel and Roberts Cross to analyze the progressive precision performance and scalability.

Package Power Distribution Current Density In Applications With Large Transient Currents, Matthew Doyle, Wiren D. Becker, Matteo Cocchini, Kyle Schoneck, Samuel Connor, Layne Berge, Siqi Bai, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

A method to model, measure, and characterize a high-transient current in an electrical packaging solution is described herein. These methods help overcome the challenge of generating model to hardware correlation in high current applications. A specialized test platform is developed and used to characterize current density in test hardware. The measurements are used to characterize a custom power distribution network and verify validity of current density predictions. This data is critical in high-current applications for finding and measuring current density through plane pinch points that can cause early failures in the field due to electromigration and delamination.

Automated Cervical Digitized Histology Whole-Slide Image Analysis Toolbox, Sudhir Sornapudi, Ravitej Addanki, R. Joe Stanley, William V. Stoecker, Rodney Long, Rosemary Zuna, Shellaine R. Frazier, Sameer Antani

Electrical and Computer Engineering Faculty Research & Creative Works

Background: Cervical intraepithelial neoplasia (CIN) is regarded as a potential precancerous state of the uterine cervix. Timely and appropriate early treatment of CIN can help reduce cervical cancer mortality. Accurate estimation of CIN grade correlated with human papillomavirus type, which is the primary cause of the disease, helps determine the patient's risk for developing the disease. Colposcopy is used to select women for biopsy. Expert pathologists examine the biopsied cervical epithelial tissue under a microscope. The examination can take a long time and is prone to error and often results in high inter-and intra-observer variability in outcomes. Methodology: We propose …

Modeling Conductive Properties Of Highly Aligned Single-Walled Carbon Nanotube And Graphene Thin Films, Mark Joseph Foster

Browse all Theses and Dissertations

Properties of layered material systems have been investigated since the 1940s and are currently very well understood. Classical mechanics combined with the well-developed lamination theory enable the prediction of multi-layered system properties once the properties of its constituents are known. The ability of the lamination theory to predict the conductive properties of multi-layered highly aligned single-walled carbon nanotube (SWCNT) and graphene thin films is investigated. Experimental results showed that the classical lamination theory is not valid in the case of the investigated nanofilm system. Using experimental results, we developed a closed form model using MATLAB which enabled the correct prediction …

Hard Hat Ambient Liability Observer (Halo), Hunter Hykes, Nathan Kish, Brian Thomson

Williams Honors College, Honors Research Projects

Capturing workplace incident information is a growing area of concern for most companies. To assist with this, the design team proposed the H.A.L.O. This design uses time-of-flight sensors connected to LEDs to create a proximity-based hazard warning system. It also records incident data using an accelerometer and micro-SD card. This helps workers avoid some of the most common workplace injuries, slips, trips, and falls and accidental collisions.

Students have created a design with engineering, and marketing requirements that accomplish this task. The proposed design allows for this monitoring and mitigation systems to be attached to hard hats. Team members developed …

Electrospinning Of Formic Acid/Acetic Acid And Nylon-6 Solutions For Wearable Hydration Sensors, Nichole Cooper, Jonathan Doak

Williams Honors College, Honors Research Projects

Students have been working on the development of wearable hydration sensors at the startup company RooSense. The goal of the company is to develop a lightweight wearable sensor that enables the user to know their hydration level, thus elevating their performance goals. To measure the hydration of the wearer, the sodium and other salt ions are collected from the user’s sweat as they exercise. This sweat is analyzed as it is collected to give the user an exact level of hydration, so they know how much fluids they need. The production of this ion sensor requires numerous steps and iteration …

Ecg Monitoring In Athletes, Jalal Jwayyed, Kelly Purgason, Joseph Linder, Annamarie Alfery, Silvia Furman

Williams Honors College, Honors Research Projects

Athletes and medical personnel need reliable methods to monitor vital signs and detect potentially life-threatening issues before they occur. Electrocardiograph (ECG) monitors are currently the best method of detecting heart-related health issues. Current ECG monitors worn by athletes are difficult to use and lack the ability to track ECGs in real time. Through research and interviews with various clinicians, further problems have been identified that include poor electrode adhesion, and a lack of compatibility with the equipment worn by athletes. Our team proposes to develop solutions that will improve performance and comfort associated with ECG monitors for athletic applications. This …

Cold Plasma Enhanced Active Sites On Supported Nip Nanoparticles For The Oxygen Evolution Reaction, Michael Ricci

Williams Honors College, Honors Research Projects

Identifying materials to efficiently facilitate the oxygen evolution reaction (OER) is key to advancing water electrolysis, an essential technology in the pathway towards a sustainable energy future. Here, we explore cold-plasma treatment as a facile method to enhance the activity of NiP nanoparticles supported on activated carbon. NiP nanoparticles were synthesized on an activated carbon support using a solid-state method and were then treated with argon, oxygen, and hydrogen plasmas for extended times. In all cases, plasma treatment reduced the number of active sites on the support. OER activity was evaluated by testing the materials in alkaline conditions. The activities …

Analyzing And Improving Calculation And Tuning Process For A Uav, Laurel Wardell

Williams Honors College, Honors Research Projects

The nature of this project is confidential and cannot be disclosed in detail. Generally, this project deals with the analysis of a control system of a UAV with several electric motors and gimbals. The goal of this analysis is to improve control calculations for increased stability. In addition, development has been started on an application to streamline the tuning of gains for this particular controller, allowing for more efficient use of precious flight time.

Development Of A Heavy-Duty Aluminum Rail Hole Punch Manufacturing Fixture, Reese Hawthorne

Williams Honors College, Honors Research Projects

This report details the development and testing of an improved replacement for a worn manufacturing fixture which was used to position the location of four drilled holes on the outside of a heavy-duty aluminum rail. Commissioned by JohnDow Industries, the new process improves upon the old one by implementing an electro-hydraulic punch and new locating fixture. The new design produced higher quality slots, decreased cycle time by 15%, and aimed to improve the ergonomics of the process for the employees. All these factors contributed to making the aluminum rails a high-quality end product for JohnDow’s customers. Further iteration of the …

Customizable Armor Set, Olivia Reedy

Williams Honors College, Honors Research Projects

This project is intended to help people who make costume armor by reducing the amount of time and money it takes to create a set of armor. Making armor can take a lot of resources for beginners, and this project is intended to help hobbyists with that process. This customizable armor set goes through the engineering design process, from the initial design of the parts to creating the prototype using vacuum forming. The prototype armor can be painted and adhered to using acrylic paint and contact cement, respectively, and fits three sizes of small, medium, and large.

Ping Pong Ball Collecting Robot, Gina Lanese, Jason Colonna, Sarah Kuchcinski, Johndavid Rogers

Williams Honors College, Honors Research Projects

The ping pong ball collecting robot will collect ping pong balls in a ping pong arena, such as after a game or practice session. Ball collection is now typically done by a human, collecting the balls either by hand or with a net. A robot, autonomously collecting the ping pong balls from the floor, would allow for the time spent playing or practicing to be maximized. The team will design the software and hardware for the robot, including the mechanical system, the software, and circuit boards. This robot will serve as a capstone project for the senior design team consisting …

Atmospheric Corrosion Of Galvanically Coupled Aluminum Alloys And Carbon Steel, Mitchell Felde

Williams Honors College, Honors Research Projects

Aluminum alloys are a steadily growing material being commonly used in lieu of typical steels. Additional alloying, heat treatment, and other property enhancing processes are expanding the use of these alloys. However, with this expansion, galvanic corrosion is becoming more of an issue in the design stage due to the combination of these alloys with steels. The automotive industry is one industry where the use of aluminum alloys is becoming common practice. Aluminum alloys provide a lightweight aspect over the conventional carbon steel that was used previously. As a result of this transition towards more lightweight materials, galvanic coupling is …