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Description
A defense-by-randomization framework is proposed as an effective defense mechanism against different types of adversarial attacks on neural networks. Experiments were conducted by selecting a combination of differently constructed image classification neural networks to observe which combinations applied to this framework were most effective in maximizing classification accuracy. Furthermore, the reasons why particular combinations were more effective than others is explored.
ContributorsMazboudi, Yassine Ahmad (Author) / Yang, Yezhou (Thesis director) / Ren, Yi (Committee member) / School of Mathematical and Statistical Sciences (Contributor) / Economics Program in CLAS (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
The oxygen sensitivity of hydrogenase is a large barrier in maximizing the efficiency of algal hydrogen production, despite recent efforts aimed at rewiring photosynthesis. This project focuses on the role of photosystem II (PSII) in extended hydrogen production by cells expressing the PSI-HydA1 chimera, with the goal of optimizing continuous production of photobiohydrogen in the green alga, Chlamydomonas reinhardtii. Experiments utilizing an artificial PSII electron
Therefore, it can be concluded that downstream processes are limiting the electron flow to the hydrogenase. It was also shown that the use of a PSII inhibitor, 3-(3,4-dichlorophenyl)-1,1- dimethylurea (DCMU), at sub-saturating concentrations under light exposure during growth temporarily improves the duration of the H2 evolution phase. The maximal hydrogen production rate was found to be approximately 32 nmol h-1 (µg Chl)-1. Although downregulation of PSII activity with DCMU improves the long-term hydrogen production, future experiments must be focused on improving oxygen tolerance of the hydrogenase as a means for higher hydrogen yields.
Therefore, it can be concluded that downstream processes are limiting the electron flow to the hydrogenase. It was also shown that the use of a PSII inhibitor, 3-(3,4-dichlorophenyl)-1,1- dimethylurea (DCMU), at sub-saturating concentrations under light exposure during growth temporarily improves the duration of the H2 evolution phase. The maximal hydrogen production rate was found to be approximately 32 nmol h-1 (µg Chl)-1. Although downregulation of PSII activity with DCMU improves the long-term hydrogen production, future experiments must be focused on improving oxygen tolerance of the hydrogenase as a means for higher hydrogen yields.
ContributorsO'Boyle, Taryn Reilly (Author) / Redding, Kevin (Thesis director) / Ghirlanda, Giovanna (Committee member) / Vermaas, Willem (Committee member) / School of Mathematical and Statistical Sciences (Contributor) / School of Life Sciences (Contributor) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
This project attempts to create an accurate numerical simulation of the eastern limb of the HH 901 jet in the Mystic Mountain formation located in the Carina Nebula. Using a 3rd order accurate WENO numerical scheme in space, and a 3rd order accurate RK method in time, the temperature, density, radiative cooling, length, and average jet velocity of this astrophysical phenomenon were simulated based on observations made by Hubble Space Telescope and the work of Reiter and Smith (2013) and (2014). The results of this simulation are displayed in three figures, one each for temperature, radiative cooling, and density, which show a jet displaying morphology consistent with that of the HH 901 eastern limb without adjustment for stellar wind. Also discussed are the effects of different jet speeds, initial conditions, and pulse parameters on the shape and behavior of the simulated jets, as well as continuing work to be done on the simulation to enhance its accuracy and usefulness.
ContributorsKreitzer, Kyle (Author) / Gardner, Carl (Thesis director) / Jones, Jeremiah (Committee member) / School of Mathematical and Statistical Sciences (Contributor) / Mechanical and Aerospace Engineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
In baseball, a starting pitcher has historically been a more durable pitcher capable of lasting long into games without tiring. For the entire history of Major League Baseball, these pitchers have been expected to last 6 innings or more into a game before being replaced. However, with the advances in statistics and sabermetrics and their gradual acceptance by professional coaches, the role of the starting pitcher is beginning to change. Teams are experimenting with having starters being replaced quicker, challenging the traditional role of the starting pitcher. The goal of this study is to determine if there is an exact point at which a team would benefit from replacing a starting or relief pitcher with another pitcher using statistical analyses. We will use logistic stepwise regression to predict the likelihood of a team scoring a run if a substitution is made or not made given the current game situation.
ContributorsBuckley, Nicholas J (Author) / Samara, Marko (Thesis director) / Lanchier, Nicolas (Committee member) / School of Mathematical and Statistical Sciences (Contributor) / Department of Information Systems (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
The purpose of this thesis is to accurately simulate the surface brightness in various spectral emission lines of the HH 901 jets in the Mystic Mountain Formation of the Carina Nebula. To accomplish this goal, we gathered relevant spectral emission line data for [Fe II] 12660 Å, Hα 6563 Å, and [S II] 6720 Å to compare with Hubble Space Telescope observations of the HH 901 jets presented in Reiter et al. (2016). We derived the emissivities for these lines from the spectral synthesis code Cloudy by Ferland et al. (2017). In addition, we used WENO simulations of density, temperature, and radiative cooling to model the jet. We found that the computed surface brightness values agreed with most of the observational surface brightness values. Thus, the 3D cylindrically symmetric simulations of surface brightness using the WENO code and Cloudy spectral emission models are accurate for jets like HH 901. After detailing these agreements, we discuss the next steps for the project, like adding an external ambient wind and performing the simulations in full 3D.
ContributorsMohan, Arun (Author) / Gardner, Carl (Thesis director) / Jones, Jeremiah (Committee member) / Computer Science and Engineering Program (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
The purpose of this thesis project is to analyze the impact that patient death has on long-term care providers. This study draws upon my own experience working as a licensed nursing assistant in a long-term care facility and also uses a qualitative analysis of six semi-structured interviews with other nursing assistants and hospice volunteers. With patient death being an unavoidable part of working in this area of healthcare, I explore how these care providers cope with losing their patients and the effectiveness of these coping mechanisms. Some strategies found that aided in coping with grief included staying detached from patients, being distracted by other aspects of the job, receiving support from co-workers, family members and/or supervisors, and having a religious outlook on what happens following death. In addition to these, I argue that care providers also utilize the unconscious defense mechanism of repression to avoid their feelings of grief and guilt. Repressing the grief and emotions that come along with patient death can protect the individual from additional pain in order for them to continue to do their difficult jobs. Being distracted by other patients also aids in the repression process by avoiding personal feelings temporarily. I also look into factors that have been found to affect the level of grief including the caregiver’s closeness to the patient, level of preparedness for the death, and first experience of losing a patient. Ultimately, I show that the common feelings accompanied by patient death (sadness, anger and stress) and the occurrence of burnout are harmful symptoms of the repression taking place.
ContributorsMasterson, Kaitlin (Author) / Loebenberg, Abby (Thesis director) / Mack, Robert (Committee member) / School of Mathematical and Statistical Sciences (Contributor) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
In September of 1540 Garcia Lopez de Cardenas, while being led by Hopi Natives, came across something no European had ever seen before. One can only imagine what must have gone through his mind as he discovered the world’s largest canyon, 18 miles across and close to 6,000 feet deep. Over the course of three days, Garcia and his scouts made attempts to enter into the canyon and to taste of its river, but, after many failed attempts, they had to make their way back to their main camp for fear of dehydration and it was left unvisited by any Europeans for over 200 years.
Now I wasn’t the first one to discover the canyon, but I remember a time when I was in the fourth grade. When I stepped out of a bus that I had been in for close to four hours and took forty footsteps to end up at a small brick wall that came close to calf-height which was meant to keep me safe. I don’t know why it didn’t hit me until this point, because I had seen pictures of its grandeur and “experienced” the so called “majesty” of the Grand Canyon through the medium of the National Geographic and tasted of the beauty of one of the natural wonders of the world through the photographs of others before, but standing face to face with a five-thousand-foot cliff humbled me and brought a fear in to me that I can’t describe. Especially when a friend of mine had violently jerked me while I was close to the edge. I remember hearing fear in my father’s voice as I got a little too close to the edge for his comfort. He wanted me to be safe, but I wanted to look this canyon in the eye.
I find it really interesting though, that both my father and I feared ME getting close to the edge. I guess it’s because we both didn’t fully trust my young and feeble knees to keep me stable while I was that close to a fall that would’ve meant sure death for me. Or maybe it was because a couple of months before this, he had seen on the news that some kid was playing too close to the edge and had fallen to his death. Or maybe, it was because, for the first time, death was actually close enough to grasp something he profoundly loved. Either way, I won’t ever forget the loving strain in his voice as he sternly said “Grant! Step a little bit further back from the edge Son.”
It’s really a shame that no one knew. Or at least that no one said anything if they did know. Especially because this New canyon I stood looking face to face with was thousands of feet deeper than the one I had been close to the edge of ten years before, and had the authority to not just kill me once, but twice, if I fell.
Now I wasn’t the first one to discover the canyon, but I remember a time when I was in the fourth grade. When I stepped out of a bus that I had been in for close to four hours and took forty footsteps to end up at a small brick wall that came close to calf-height which was meant to keep me safe. I don’t know why it didn’t hit me until this point, because I had seen pictures of its grandeur and “experienced” the so called “majesty” of the Grand Canyon through the medium of the National Geographic and tasted of the beauty of one of the natural wonders of the world through the photographs of others before, but standing face to face with a five-thousand-foot cliff humbled me and brought a fear in to me that I can’t describe. Especially when a friend of mine had violently jerked me while I was close to the edge. I remember hearing fear in my father’s voice as I got a little too close to the edge for his comfort. He wanted me to be safe, but I wanted to look this canyon in the eye.
I find it really interesting though, that both my father and I feared ME getting close to the edge. I guess it’s because we both didn’t fully trust my young and feeble knees to keep me stable while I was that close to a fall that would’ve meant sure death for me. Or maybe it was because a couple of months before this, he had seen on the news that some kid was playing too close to the edge and had fallen to his death. Or maybe, it was because, for the first time, death was actually close enough to grasp something he profoundly loved. Either way, I won’t ever forget the loving strain in his voice as he sternly said “Grant! Step a little bit further back from the edge Son.”
It’s really a shame that no one knew. Or at least that no one said anything if they did know. Especially because this New canyon I stood looking face to face with was thousands of feet deeper than the one I had been close to the edge of ten years before, and had the authority to not just kill me once, but twice, if I fell.
ContributorsWallace, Grant Winslow (Author) / Mirguet, Francoise (Thesis director) / Delacruz, Julian (Committee member) / School of Mathematical and Statistical Sciences (Contributor) / Department of Economics (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
The aim of the present study was to review the symptoms and current treatment options of the most common skin infections seen in outpatient settings and develop a preliminary alternative treatment solution. The specific skin infections evaluated were those caused by Staphylococcus and Streptococcus bacterial species, and are frequently treated with a wide variety of systemic antibiotics or topical ointments. Systemic antibiotics have shown increased occurrence of adverse side effects as well as the development of antibiotic-resistant bacteria. Additionally, these medications are usually overprescribed, which may further exacerbate negative side effects. Another issue that is addressed is the development of infections following treatment of a new laceration or other trauma to the skin. A patient may be treated for their wound with stitches or another alternative, but there is still the possibility of developing an infection later.
This study synthesizes information found from extensive research and provides a review of the most optimal techniques for developing an alternative to systemic antibiotics. The final deliverable is a report detailing the significant findings and discussing the ways that this solution may be developed further and implemented in a clinical setting. The solution is a hydrogel bandage designed to deliver antibiotics directly to the wound site, while also offering protection and enhanced wound healing. The target population is patients suffering from skin conditions in an outpatient setting. The antibiotics of interest for this solution are clindamycin, doxycycline, and trimethoprim-sulfamethoxazole (co-trimoxazole), as they offer excellent treatment against gram-positive bacteria and methicillin-resistant Staphylococcus aureus. However, other broad-spectrum antibiotics could potentially be incorporated to protect against gram-negative bacteria. The design features a polyvinyl alcohol (PVA) hydrogel that has shown many properties that are beneficial to biomedical applications, including biocompatibility, flexibility, high drug-loading capacity, high absorption of wound exudate, increased promotion of wound healing, and more. Preliminary mathematical models of the hydrogel’s drug delivery behaviors are also included. Due to the scope and timeframe of this project, the majority of findings herein are based on research of prior literature instead of development of the novel device. Future directions would include further research and development of the mechanisms behind the device, creation of a physical prototype, experimental testing, and statistical analyses to verify device specifications and capabilities.
This study synthesizes information found from extensive research and provides a review of the most optimal techniques for developing an alternative to systemic antibiotics. The final deliverable is a report detailing the significant findings and discussing the ways that this solution may be developed further and implemented in a clinical setting. The solution is a hydrogel bandage designed to deliver antibiotics directly to the wound site, while also offering protection and enhanced wound healing. The target population is patients suffering from skin conditions in an outpatient setting. The antibiotics of interest for this solution are clindamycin, doxycycline, and trimethoprim-sulfamethoxazole (co-trimoxazole), as they offer excellent treatment against gram-positive bacteria and methicillin-resistant Staphylococcus aureus. However, other broad-spectrum antibiotics could potentially be incorporated to protect against gram-negative bacteria. The design features a polyvinyl alcohol (PVA) hydrogel that has shown many properties that are beneficial to biomedical applications, including biocompatibility, flexibility, high drug-loading capacity, high absorption of wound exudate, increased promotion of wound healing, and more. Preliminary mathematical models of the hydrogel’s drug delivery behaviors are also included. Due to the scope and timeframe of this project, the majority of findings herein are based on research of prior literature instead of development of the novel device. Future directions would include further research and development of the mechanisms behind the device, creation of a physical prototype, experimental testing, and statistical analyses to verify device specifications and capabilities.
ContributorsTanner, Emily Christine (Author) / Pizziconi, Vincent (Thesis director) / Nguyen, Eric (Committee member) / Harrington Bioengineering Program (Contributor, Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
Cities are living systems. Their form and function are constantly changing to reflect the preferences and needs of their residents. One process of change in a city occurs when rapid investment pours into a neighborhood that was previously neglected. This so-called revitalization serves as a catalyst for many city improvements like new residential buildings, glamours commercial complexes, and even enhanced public transit. This process, also known as gentrification, can be a force for good as it results in population growth and economic opportunity. But with enough investment, prices -- including rent -- can be forced upwards equally as rapid. This is when gentrification can result in potentially negative outcomes for residents who can not keep up with the rent increases and are displaced from a city. Culture, as defined by people and business in an area, is the pride of many cities. A loss of culture through displacement is an outcome that anti-gentrification advocates want to avoid. But, cultural displacement may not always comprise a loss. In certain cases, displacement is just the natural byproduct of city evolution. An ideal solution to this state of affairs would be for cities to encourage gentrification while discouraging displacement. This study will explore how.
ContributorsFerrara, Justin Christopher (Author) / Simeone, Michael (Thesis director) / Baskin, Connor (Committee member) / Department of Economics (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Department of Information Systems (Contributor) / Department of Finance (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
In the modern world with the ever growing importance of technology, the challenge of information security is of increasing importance. Cryptographic algorithms used to encode information stored and transmitted over the internet must be constantly improving as methodology and technology for cyber attacks improve. RSA and Elliptic Curve cryptosystems such as El Gamal or Diffie-Hellman key exchange are often used as secure asymmetric cryptographic algorithms. However, quantum computing threatens the security of these algorithms. A relatively new algorithm that is based on isogenies between elliptic curves has been proposed in response to this threat. The new algorithm is thought to be quantum resistant as it uses isogeny walks instead of point addition to generate a shared secret key. In this paper we will analyze this algorithm in an attempt to understand the theory behind it. A main goal is to create isogeny graphs to visualize degree 2 and 3 isogeny walks that can be taken between supersingular elliptic curves over small fields to get a better understanding of the workings and security of the algorithm.
ContributorsLoucks, Sara J (Author) / Jones, John (Thesis director) / Bremner, Andrew (Committee member) / Computer Science and Engineering Program (Contributor) / School of Film, Dance and Theatre (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05