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Full-Text Articles in Engineering

Learning & Planning For Self-Driving Ride-Hailing Fleets, Jack Morris May 2020

Learning & Planning For Self-Driving Ride-Hailing Fleets, Jack Morris

Undergraduate Honors Theses

Through simulation, we demonstrate that incorporation of self-driving vehicles into ride-hailing fleets can greatly improve urban mobility. After modeling existing driver-rider matching algorithms including Uber’s Batched Matching and Didi Chuxing’s Learning and Planning approach, we develop a novel algorithm adapting the latter to a fleet of Autos – self-driving ride-hailing vehicles – and Garages – specialized hubs for storage and refueling. By compiling driver-rider matching, idling, storage, refueling, and redistribution decisions in one unifying framework, we enable a system-wide optimization approach for self-driving ride-hailing previously unseen in the literature. In contrast with existing literature that labeled driverless taxis as economically infeasible ...


Gait Characterization Using Computer Vision Video Analysis, Martha T. Gizaw May 2020

Gait Characterization Using Computer Vision Video Analysis, Martha T. Gizaw

Undergraduate Honors Theses

The World Health Organization reports that falls are the second-leading cause of accidental death among senior adults around the world. Currently, a research team at William & Mary’s Department of Kinesiology & Health Sciences attempts to recognize and correct aging-related factors that can result in falling. To meet this goal, the members of that team videotape walking tests to examine individual gait parameters of older subjects. However, they undergo a slow, laborious process of analyzing video frame by video frame to obtain such parameters. This project uses computer vision software to reconstruct walking models from residents of an independent living retirement ...


Development And Upgrade Of A Laser Cooling And Trapping System Of Ultracold Potassium Atoms, Bennett Atwater May 2020

Development And Upgrade Of A Laser Cooling And Trapping System Of Ultracold Potassium Atoms, Bennett Atwater

Undergraduate Honors Theses

This thesis describes work to improve the apparatus that cools and loads potassium atoms onto the atom chip. This work consists of two main thrusts: a laser trap translator to help cool and load atoms onto the atom chip and a temperature stabilization system for the lasers that are used to laser cool potassium atoms. The current iteration of the beam translator has the ability to vertically translate a beam ±4.5 mm relative to its incident height. The translator has been shown to not alter the spatial profile of the beam through interference or obstruction. The translator’s rotation ...


Growth And Properties Of Vapor Diffused Nb3sn Coating For Superconducting Radiofrequency Accelerator Cavity Applications, Uttar Last Pudasaini Jan 2020

Growth And Properties Of Vapor Diffused Nb3sn Coating For Superconducting Radiofrequency Accelerator Cavity Applications, Uttar Last Pudasaini

Dissertations, Theses, and Masters Projects

The desire to reduce construction and operating costs of future SRF accelerators motivates the search for higher-performing alternative materials. Nb3Sn (Tc ~ 18.3 K and Hsh ~ 425 mT) is the front runner. The tin vapor diffusion process is currently the technique of choice to produce promising Nb3Sn-coated cavities. Understanding Nb3Sn nucleation and growth in this process is essential to progress. Samples representing different stages of Nb3Sn formation have been produced and studied to elucidate the effects of nucleation, growth, process conditions, and impurities. Nb3Sn films with thickness from ...


Construction Of An Auger Microscope, Charles Soulen May 2019

Construction Of An Auger Microscope, Charles Soulen

Undergraduate Honors Theses

This thesis describes the design, adaptations and characterizations necessary to partially turn an Auger Electron Spectroscopy Instrument (AES) into an Auger Electron Microscope (AEM). The completed AEM will be able to scan and characterize materials over an area, unlike the AES which only took data from a single point. However, due to time constraints, this thesis only partially describes the creation of an AEM. We were able to show proof-of-concept, though, we were unable to run AEM on a material. We have also increased the theoretical accuracy of the instrument by replacing decades-old electronics with modern alternatives. Again, due to ...


Using Gleaned Computing Power To Forecast Emerging-Market Equity Returns With Machine Learning, Xida Ren Apr 2019

Using Gleaned Computing Power To Forecast Emerging-Market Equity Returns With Machine Learning, Xida Ren

Undergraduate Honors Theses

This paper examines developing machine learning and statistic models to build forecast models for equity returns in an emergent market, with an emphasis on computing. Distributed systems were pared with random search and Bayesian optimization to find good hyperparameters for neural networks. No significant results were found.


Optical Characterization Of Dynamic Exchange Coupling Interaction In Ferromagnetic Heterostructures, Xiao Liu Jan 2019

Optical Characterization Of Dynamic Exchange Coupling Interaction In Ferromagnetic Heterostructures, Xiao Liu

Dissertations, Theses, and Masters Projects

This thesis presents the optical characterization of interfacial exchange coupling interaction in ferromagnetic bilayer heterostructures. Both static and dynamic magnetic response are investigated in the exchange-coupled Co2FeAl/(Ga,Mn)As bilayer system using static magneto-optical Kerr effect (MOKE) and time-resolved magneto optical Kerr effect (TRMOKE) techniques. The goal of this thesis is to understand the underlying physics of the interfacial exchange coupling effect on the ultrafast spin dynamics in a ferromagnetic metal/ferromagnetic semiconductor bilayer heterostructure. Our finding provides a viable pathway for designing advanced semiconductor spintronic devices for ultrafast low-power spin manipulation. First, a significant enhancement of the excitation ...


Clarity: An Exploration Of Semantic Information Encoded In Mobile Application Guis, Michael J. Curcio May 2018

Clarity: An Exploration Of Semantic Information Encoded In Mobile Application Guis, Michael J. Curcio

Undergraduate Honors Theses

Upon installing a mobile application, human beings are able, to a great extent, to know immediately what the subcomponents of the screen do. They know what buttons return them to the previous screen, which ones submit their log in information, and which brings up the menu. This is the result of a combination of intuitive design and cross-platform design standards which allow users to draw on previous experience. Regardless, the fact that humans are able to understand the functionality of screen components at a glance suggests that there is semantic information encode into a mobile application’s GUI. In this ...


Diatomaceous Solar Cells, Jesse Granger Apr 2018

Diatomaceous Solar Cells, Jesse Granger

Undergraduate Honors Theses

An experiment was conducted at the college of William and Mary to explore the ability of wild type diatoms to enhance the abilities of a Dye-Sensitized Solar Cell (DSSC). The goal was to see if the efficiency of a solar cell could be enhanced by the addition of wild-type diatoms in the active layer of the cell, and if there was any notable advantage to using diatoms where the frustule material had been altered. For this purpose, diatoms were cleaned using near-boiling baths of hydrogen peroxide and then coated in Titanium Dioxide using a peptide-mediated deposition [1]. Diatoms were tested ...


Continuing Improvements Of The Sharkduino Animal Tag System, William Laney Dec 2017

Continuing Improvements Of The Sharkduino Animal Tag System, William Laney

Undergraduate Honors Theses

Much about the movement and habits of marine animals is still unknown. This information can be found for terrestrial animals through direct observation or video surveillance; however, these optical methods are not effective in aquatic environments. To circumvent this problem, researchers “tag” aquatic animals with small sensor systems that record data about the animals movements. The researchers then recover the tag and use signal analysis to draw conclusions about the habits of the animal. Unfortunately, commercially available tags are expensive and most can only be used once. We created an inexpensive and reusable tag to be used on sandbar sharks ...


Security Enhancements In Voice Over Ip Networks, Seyed Amir Iranmanesh Nov 2017

Security Enhancements In Voice Over Ip Networks, Seyed Amir Iranmanesh

Dissertations, Theses, and Masters Projects

Voice delivery over IP networks including VoIP (Voice over IP) and VoLTE (Voice over LTE) are emerging as the alternatives to the conventional public telephony networks. With the growing number of subscribers and the global integration of 4/5G by operations, VoIP/VoLTE as the only option for voice delivery becomes an attractive target to be abused and exploited by malicious attackers. This dissertation aims to address some of the security challenges in VoIP/VoLTE. When we examine the past events to identify trends and changes in attacking strategies, we find that spam calls, caller-ID spoofing, and DoS attacks are ...


Surface Modification Of Synthetic And Natural Polymers Using Deep Uv (172 Nm) Irradiation, Lopamudra Das Nov 2017

Surface Modification Of Synthetic And Natural Polymers Using Deep Uv (172 Nm) Irradiation, Lopamudra Das

Dissertations, Theses, and Masters Projects

The ability to modify the surfaces of polymers and impart desirable functionalities without affecting the bulk-mediated physical properties is vital for advanced materials development. Photochemical approaches to surface modification are particularly attractive as they minimize the need for use of hazardous materials used in conventional wet chemical technologies, and are relatively faster, efficient and convenient to use. In this research, we undertook a combined experimental and computational approach to understand the effect of deep UV irradiation on a broad range of polymeric materials, and develop a scalable and deployable surface modification strategy that could be extended to all. Four polyesters ...


Surfactant Free Emulsion Polymerization Of Poly(Styrene-Co-Methyl Methacrylate): Correlation Of Microsphere Characteristics With Monomer Reactivity And Water Solubility, Samantha Applin Oct 2017

Surfactant Free Emulsion Polymerization Of Poly(Styrene-Co-Methyl Methacrylate): Correlation Of Microsphere Characteristics With Monomer Reactivity And Water Solubility, Samantha Applin

Dissertations, Theses, and Masters Projects

Polymeric microspheres have been used in a broad range of applications from chromatographic separation techniques to analysis of air flow over aerodynamic surfaces. The preparation of microspheres from many polymer families has consequently been extensively studied using a variety of synthetic approaches. Although there are a myriad of polymeric microsphere synthesis methods, free-radical initiated emulsion polymerization is one of the most common techniques. In this work, poly(styrene-co-methyl methacrylate) microspheres were synthesized via surfactant-free emulsion polymerization. The effects of the co-monomer composition and addition time on particle size distribution, particle formation, and particle morphology were investigated. Particles were characterized using ...


Vertically Oriented Graphene Electric Double Layer Capacitors, Dilshan V. Premathilake Jun 2017

Vertically Oriented Graphene Electric Double Layer Capacitors, Dilshan V. Premathilake

Dissertations, Theses, and Masters Projects

Vertically oriented graphene nanosheets (VOGN) synthesized by radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) have been fabricated as electrical double layer capacitors (EDLCs). The relatively open morphology of the films provided good frequency response, but had limited capacitance compared to present day activated carbon EDLCs. The objective of this research was to improve the capacitance of these films to a commercially viable level while maintaining sufficient frequency response for AC filtering. The growth of VOGN on Ni and Al substrates has been studied in this work. The native oxide on Ni was thinned at temperatures above ~600ºC with the ...


Optogenetic Investigations Of The Prebötzinger Complex: Support For The Dbx1 Core Hypothesis, Francis D. Pham May 2017

Optogenetic Investigations Of The Prebötzinger Complex: Support For The Dbx1 Core Hypothesis, Francis D. Pham

Undergraduate Honors Theses

The preBötzinger complex (preBötC) is the central pattern generator for inspiratory behaviors. Previous studies on perinatal mice and in vitro suggest that Dbx1-derived neurons within the preBötC form the core oscillator. Here, we provide support for the Dbx1 core hypothesis and show that Dbx1-derived neurons are essential for respiratory rhythmogenesis in adult mice. Using optogenetic strategies, we transiently hyperpolarized Dbx1 neurons of the preBötC in vitro and in adult mice. In both cases, the inspiratory rhythm was disrupted. It is possible that axons from Dbx1 neurons projecting into the preBötC were also hyperpolarized, leading to disfacilitation. To determine if this ...


Characterization Of Neural Network Backpropagation On Chiplet-Based Gpu Architectures, Colin A. Weinshenker Apr 2017

Characterization Of Neural Network Backpropagation On Chiplet-Based Gpu Architectures, Colin A. Weinshenker

Undergraduate Honors Theses

Advances in parallel computing architectures (e.g., Graphics Processing Units (GPUs)) have had great success in helping meet the performance and energy-efficiency demands of many high-performance computing (HPC) applications. DRAM bandwidth is generally a critical performance bottleneck for many of such applications. With the advances in memory technology, the DRAM bandwidth bottleneck is shifting towards other parts of the system hierarchy (e.g., interconnects). We identify neural network backpropagation as one application where the interconnect network is one of the biggest performance bottlenecks. We show that the interconnect bottleneck for backpropagation can be significantly alleviated if computing cores and caching ...


The Thin Ribbon Silk Of The Brown Recluse Spider: Structure, Mechanical Behavior, And Biomimicry, Sean Robert Koebley Oct 2016

The Thin Ribbon Silk Of The Brown Recluse Spider: Structure, Mechanical Behavior, And Biomimicry, Sean Robert Koebley

Dissertations, Theses, and Masters Projects

Silk has enormous potential as a next-generation material: it is a biopolymer spun from protein at ambient temperature and pressure, and the best spider silks are as strong as steel and tougher than Kevlar. Because of its green production, mechanical robustness, and biocompatibility, silk has been researched for use in a range of engineering and biomedical applications. However, despite exciting recent advances in artificial silk fabrication via recombinant techniques, reserachers remain unable to fully replicate the complex assembly and hierarchical structure of native silks. Herein, we describe our morphological and mechanical characterization of a uniquely simple model silk system that ...


Synthesis And Characterization Of Interpenetrating Polymer Networks For Applications In Extraterrestrial Radiation Shielding, Josiah Arevalo Hammack May 2016

Synthesis And Characterization Of Interpenetrating Polymer Networks For Applications In Extraterrestrial Radiation Shielding, Josiah Arevalo Hammack

Undergraduate Honors Theses

During interplanetary voyages spacecraft are exposed to a variety of ionizing radiations, including high intensity electromagnetic radiation and galactic cosmic rays, creating conditions that are harmful to both instrumentation and human passengers. Current shielding methods offer a degree of protection, but they are not suitable for long term missions or for habitation on extraterrestrial environments, and traditional terrestrial shields are too heavy to be carried on these missions. Organic polymers offer a versatile, lightweight solution to many of the difficulties in shielding, however they also present difficulties establishing a sufficiently high hydrogen content while maintaining high mechanical and thermal stability ...


Development Of A Digital Offset Laser Lock, Ian W. Hage May 2016

Development Of A Digital Offset Laser Lock, Ian W. Hage

Undergraduate Honors Theses

An offset laser lock is an optoelectronic system capable of stabilizing a laser's optical frequency to a variable offset from another stable laser's frequency. The lock system described in this report relies on a digital frequency comparison of the beat note of two lasers to determine and fix the frequency difference, or offset, between them. This thesis describes the construction of a configurable proportional-integral (PI) control circuit to regulate a laser's frequency based on the error signal generated by a digital comparison of the beat note frequency, as well as the integration of formerly unconnected circuit elements ...


Modeling Flocculation And Deflocculation Processes Of Cohesive Sediments, Xiaoteng Shen Jan 2016

Modeling Flocculation And Deflocculation Processes Of Cohesive Sediments, Xiaoteng Shen

Dissertations, Theses, and Masters Projects

The transport and fate of cohesive sediments are responsible for many engineering, environmental, economic and policy issues that relate to, for example, siltation and dredging in navigation channels, water quality, water turbidity, pollutant transports, and biological ecosystem responses. Our current understanding, however, is insufficient to conduct accurate quantitative predictions of these processes. This is because the cohesive particles in natural waters will flocculate, which determines the settling, and thus the deposition behaviors. The simulation of flocculation processes is a primary challenge since the time variation of Floc Size Distribution (FSD) is controlled by a partial differential equation that also contains ...


Investigation Of The Interaction Between Graphene Oxide And A Biopolymer Surface, Pei Pang May 2015

Investigation Of The Interaction Between Graphene Oxide And A Biopolymer Surface, Pei Pang

Undergraduate Honors Theses

Graphene oxide (GO) is functionalized graphene sheet. Due to its exceptional mechanical properties, GO is widely considered a promising filler material for producing nanocomposites. Biopolymers are polymers produced by living organism. They are as strong and tough as synthetic polymers, yet feature exceptional biocompatibility. The combination of GO and biopolymers, then, can yield potential novel nanocomposites. These novel materials have the potential to possess a combination of outstanding properties. They would be thin, lightweight, strong, and biocompatible. Therefore, these materials can have many applications in various fields, such as biocompatible coatings and body implants. In this project, we report an ...


Assessing The Impact Of Climate Change On Proposed Restoration Of The Lynnhaven River Ecosystem, Emily E. Skeehan Jan 2015

Assessing The Impact Of Climate Change On Proposed Restoration Of The Lynnhaven River Ecosystem, Emily E. Skeehan

Dissertations, Theses, and Masters Projects

Environmental degradation of the Chesapeake Bay (CB) and its sub-estuaries has been linked to population growth in the surrounding coastal zone, rapid development in the watershed and resultant nutrient loading into the Bay. Consequently, the federal government and its partners have developed restoration plans to mitigate the effects of eutrophication and improve essential ecosystem functions, though few restoration plans have considered the interactive effects of climate change. Climate change and other anthropogenic drivers are causing changes in ecosystem structure and function, thereby impacting the beneficial services ecosystems provide. While some studies have attempted to quantitatively predict the benefits of ecosystem ...


Development Of Boron-Containing Polyimide Materials And Poly(Arylene Ether)S For Radiation Shielding, Brittani May Collins Jan 2015

Development Of Boron-Containing Polyimide Materials And Poly(Arylene Ether)S For Radiation Shielding, Brittani May Collins

Dissertations, Theses, and Masters Projects

No abstract provided.


Canary Red: Preserving Cochineal And Contrasting Colonial Histories On Lanzarote, Sarah Mattes Jan 2015

Canary Red: Preserving Cochineal And Contrasting Colonial Histories On Lanzarote, Sarah Mattes

Dissertations, Theses, and Masters Projects

No abstract provided.


Study Of Oil-Mineral Interactions By Atomic Force Spectroscopy, Jeffrey S. Knox May 2014

Study Of Oil-Mineral Interactions By Atomic Force Spectroscopy, Jeffrey S. Knox

Undergraduate Honors Theses

In many reservoirs, oil recovery is limited by the tendency of oil to adhere to surrounding mineral surfaces. Modern injection well techniques force fluids into the reservoir to enhance recovery by raising the hydrostatic pressure, but still leave behind a significant amount of the oil. Attractive intermolecular forces, especially van der Waals forces, are responsible for these inefficiencies; however, the relative strength of electrostatic repulsion in the solution also plays a role. This study seeks to maximize oil recovery by determining the factors that lead to adhesion at the nanoscale, thus allowing for optimized recovery techniques to be employed.

Atomic ...


Effective Resource And Workload Management In Data Centers, Lei Lu Jan 2014

Effective Resource And Workload Management In Data Centers, Lei Lu

Dissertations, Theses, and Masters Projects

The increasing demand for storage, computation, and business continuity has driven the growth of data centers. Managing data centers efficiently is a difficult task because of the wide variety of datacenter applications, their ever-changing intensities, and the fact that application performance targets may differ widely. Server virtualization has been a game-changing technology for IT, providing the possibility to support multiple virtual machines (VMs) simultaneously. This dissertation focuses on how virtualization technologies can be utilized to develop new tools for maintaining high resource utilization, for achieving high application performance, and for reducing the cost of data center management.;For multi-tiered applications ...


Use Of Pattern Classification Algorithms To Interpret Passive And Active Data Streams From A Walking-Speed Robotic Sensor Platform, Eric Allen Dieckman Jan 2014

Use Of Pattern Classification Algorithms To Interpret Passive And Active Data Streams From A Walking-Speed Robotic Sensor Platform, Eric Allen Dieckman

Dissertations, Theses, and Masters Projects

In order to perform useful tasks for us, robots must have the ability to notice, recognize, and respond to objects and events in their environment. This requires the acquisition and synthesis of information from a variety of sensors. Here we investigate the performance of a number of sensor modalities in an unstructured outdoor environment, including the Microsoft Kinect, thermal infrared camera, and coffee can radar. Special attention is given to acoustic echolocation measurements of approaching vehicles, where an acoustic parametric array propagates an audible signal to the oncoming target and the Kinect microphone array records the reflected backscattered signal. Although ...


An Evaluation Of A Reduced Bar Spacing Turtle Excluder Device In The U.S Gulf Of Mexico Offshore Shrimp Trawl Fishery, Michel Anthony Nalovic Jan 2014

An Evaluation Of A Reduced Bar Spacing Turtle Excluder Device In The U.S Gulf Of Mexico Offshore Shrimp Trawl Fishery, Michel Anthony Nalovic

Dissertations, Theses, and Masters Projects

Shrimp are the most economically valuable internationally-traded seafood commodity, and wild-caught, trawled shrimp make up almost half of the ~6.6 million metric tons of annual global production. Shrimp trawling is responsible for one-third of the world’s total fisheries bycatch, leading many to consider shrimp trawling to be the single most destructive fishing practice in the world. Though the bycatch of large marine animals can be significantly reduced by use of turtle excluder devices (TEDs) on shrimp trawls, current TED designs are ineffective at reducing the capture of smaller organisms which represent a large portion of the total bycatch ...


Nonlinear Optical Studies Of Photoelastic Effect And Magneto-Plasmonics, Wei Zheng Jan 2014

Nonlinear Optical Studies Of Photoelastic Effect And Magneto-Plasmonics, Wei Zheng

Dissertations, Theses, and Masters Projects

Nonlinear optical (NLO) processes are optical phenomena involving a nonlinear response to an applied light field. Two kinds of nonlinearities are studied in this dissertation: magnetic-induced second-harmonic generation (MSHG) interacting with surface plasmon, called "nonlinear magnetoplasmonics" (NMP), and the nonlinear index induced by a strong pump beam in Titanium doped sapphire crystal, referred to as population-induced nonlinear index effect.;The fundamentals of the major effects involved are discussed, which include: surface plasmon and its field enhancement effect, MSHG technique and phenomenological calculations, the contrast ratio of magnetic switching, the calculation of lensing effects, population induced strain, and photoelastic effect. Furthermore ...


Magneto-Optics And Magneto-Transport Studies On Thin Films For Sensor Applications, Kaida Yang Jan 2014

Magneto-Optics And Magneto-Transport Studies On Thin Films For Sensor Applications, Kaida Yang

Dissertations, Theses, and Masters Projects

Recent progress and interest have bought considerable effort to bear on the synthesis and opportunities of magnetic thin films in different fields. There are applications in many fields, including remote sensing, waveguide applications, hard drive applications, etc. at the College of William and Mary, we have focused on utilizing magnetic thin films in some of these applications and are deeply involved in the optimization process of the thin films.