Physical Sciences and Mathematics Commons^™

Flexible And Robust Iterative Methods For The Partial Singular Value Decomposition, Steven Goldenberg

Dissertations, Theses, and Masters Projects

The Singular Value Decomposition (SVD) is one of the most fundamental matrix factorizations in linear algebra. As a generalization of the eigenvalue decomposition, the SVD is essential for a wide variety of fields including statistics, signal and image processing, chemistry, quantum physics and even weather prediction. The methods for numerically computing the SVD mostly fall under three main categories: direct, iterative, and streaming. Direct methods focus on solving the SVD in its entirety, making them suitable for smaller dense matrices where the computation cost is tractable. On the other end of the spectrum, streaming methods were created to provide an …

Diel, Seasonal, And Interannual Changes In Coastal Antarctic Zooplankton Community Composition And Trophic Ecology, John A. Conroy

Dissertations, Theses, and Masters Projects

Throughout the ocean, zooplankton transfer energy from primary producers to higher predators and transport carbon from surface waters to depth. The efficiency of these processes depends in part upon the taxonomic composition and trophic ecology of the zooplankton community. Zooplankton species abundance and distribution shifted over recent decades along the West Antarctic Peninsula during a period of rapid regional warming and sea-ice decline. Although conducted within the context of long-term change, this dissertation research focuses on zooplankton dynamics at finer temporal scales that have received less attention. I analyzed depth-stratified net samples to investigate zooplankton diel vertical migration during Antarctic …

Characterization Of Indoor Surface Films By High-Resolution Mass Spectrometry, Emily Nicole Legaard

Dissertations, Theses, and Masters Projects

Atmospheric chemistry has primarily focused on outdoor environments for many decades. Plenty of models based on the findings of outdoor atmospheric researchers have been built to deepen the understanding of outdoor environments and predict how certain changes in specific parameters may affect the overall atmosphere. The same cannot be said for indoor environments, which remain relatively unknown despite the fact that humans in developed countries spend the vast majority of their lives in indoor environments. This thesis seeks to provide an early look at the makeup of indoor surface films, specifically at their molecular compositions and thicknesses. These characteristics are …

Across-Scale Energy Transfer In The Southern Ocean, Laur Ferris

Dissertations, Theses, and Masters Projects

Numerous physics are responsible for forward energy cascade at oceanic fronts but their roles are not fully clear. This dissertation investigates wind-sheared turbulence in the ocean surface boundary layer (OSBL), internal wave interactions in the ocean interior, and instability-driven turbulence in energetic jets; with attention paid to the parameterizations used to quantify them. At the OSBL, meteorological forcing injects turbulent kinetic energy (TKE), mixing the upper ocean and rapidly transforming its density structure. In the absence of direct observations or capability to resolve sub-grid scale turbulence in ocean models, the community relies on boundary layer scalings (BLS) of shear and …

Improving The Holographic Recording Characteristics Of A Water-Resistant Photosensitive Sol–Gel For Use In Volume Holographic Optical Elements, Brian Rogers, Tatsiana Mikulchyk, Mohamed Oubaha, Dervil Cody, Suzanne Martin, Izabela Naydenova

Articles

Continual improvements to holographic recording materials make the development of volume holographic optical elements increasingly more attainable for applications where highly efficient, lightweight diffractive optical elements can replace conventional optics. A fast-curing, water resistant photosensitive sol–gel capable of volume holographic recording has recently drawn attention for its extreme environmental and physical robustness, in particular its water/moisture and scratch resistance. However, to date, the refractive index modulation has been limited. While water-resistant properties are invaluable in the face of the weathering which many practical systems for outdoor applications will endure, high refractive index modulation is also important in order to facilitate …

Charge Transfer Mediated Triplet Excited State Formation In Donor-Acceptor-Donor Bodipy: Application For Recording Of Holographic Structures In Photopolymerizable Glass, Tatsiana Mikulchyk, Safakath Karuthedath, Catherine S.P. De Castro, Andrey A. Buglak, Aimee Sheehan, Aaron Wieder, FréDéRic Laquai, Izabela Naydenova, Mikhail Filatov

Articles

Donor–acceptor–donor BODIPY triads bearing anthracene or pyrene as electron donating subunits were prepared through a stepwise synthesis. Photoinduced electron transfer and formation of long-lived triplet excited states via spin–orbit charge transfer intersystem crossing (SOCT-ISC) was studied by steady-state and ultrafast pump-probe spectroscopy and further supported by DFT computations. New BODIPYs were found to form triplet states and sensitize singlet oxygen in both polar and non-polar solvents which is unusual for photosensitizers operating via SOCT-ISC. BODIPY-anthracene triad (ABA) was used as a photosensitizer component in a photopolymerizable glass that was prepared by a four-step sol–gel process. ABA in combination with N …

A Metric For Machine Learning Vulnerability To Adversarial Examples, Matt Bradley

Masters Theses & Doctoral Dissertations

Machine learning is used in myriad aspects, both in academic research and in everyday life, including safety-critical applications such as robust robotics, cybersecurity products, medial testing and diagnosis where a false positive or negative could have catastrophic results. Despite the increasing prevalence of machine learning applications and their role in critical systems we rely on daily, the security and robustness of machine learning models is still a relatively young field of research with many open questions, particularly on the defensive side of adversarial machine learning. Chief among these open questions is how best to quantify a model’s attack surface against …

Saturating Relationship Between Phytoplankton Growth Rate And Nutrient Concentration Explained By Macromolecular Allocation, Jongsun Kim, Gabrielle Armin, Keisuke Inomura

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Phytoplankton account for about a half of photosynthesis in the world, making them a key player in the ecological and biogeochemical systems. One of the key traits of phytoplankton is their growth rate because it indicates their productivity and affects their competitive capability. The saturating relationship between phytoplankton growth rate and environmental nutrient concentration has been widely observed yet the mechanisms behind the relationship remain elusive. Here we use a mechanistic model and metadata of phytoplankton to show that the saturating relationship between growth rate and nitrate concentration can be interpreted by intracellular macromolecular allocation. At low nitrate levels, the …

Native And Non-Native Plant Species Differentially Affect Arthropod Community Dynamics With Consequences For Crop Production In Lower Rio Grande Valley, Kaitlynn Lavallee, Pushpa G. Soti, Alexis Racelis, Rupesh R. Kariyat

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

In agricultural ecosystems, arthropods play critical roles- including biocontrol, pollination services, and as herbivores. While herbivory negatively affects crop production, the recent decline in beneficial insect numbers have created a global concern, and consequently have led into multiple lines of conservation strategies. Agroecological practices that can provide sustenance, nesting, and refuge for beneficial organisms are considered as some of them, except we lack a better understanding of how seasonal and crop specific variation can affect their community dynamics. In this study, we examined this by investigating how native and non-native plants, when incorporated into a vegetable agroecosystem in Lower Rio …

Harnessing The Power Of Interdisciplinary Research With Psychology-Informed Cyberbullying Detection Models, Deborah Hall, Yasin N. Silva, Brittany Wheeler, Lu Cheng, Katie Baumel

Computer Science: Faculty Publications and Other Works

Cyberbullying has become increasingly prevalent, particularly on social media. There has also been a steady rise in cyberbullying research across a range of disciplines. Much of the empirical work from computer science has focused on developing machine learning models for cyberbullying detection. Whereas machine learning cyberbullying detection models can be improved by drawing on psychological theories and perspectives, there is also tremendous potential for machine learning models to contribute to a better understanding of psychological aspects of cyberbullying. In this paper, we discuss how machine learning models can yield novel insights about the nature and defining characteristics of cyberbullying and …

Proxy Re-Encryption In Blockchain-Based Application, Wangcheng Yuan

Master's Projects

Nowadays, blockchain-based technology has risen to a new dimension. With the advantage of the decentralized identity, data are transferred through decentralized and public ledgers. Those new contracts provide great visibility. However, there is still a need to keep some data private in many cases. Those private data should be encrypted while still benefiting from the decentralized on-chain protocol. Securing those private data in such a decentralized blockchain-based system is thus a critical problem. Our solution provides a decentralized protocol that lets users grant access to their private data with proxy re-encryption in SpartanGold (a blockchain-based cryptocurrency). We implement a third-party …

Caption And Image Based Next-Word Auto-Completion, Meet Patel

Master's Projects

With the increasing number of options or choices in terms of entities like products, movies, songs, etc. which are now available to users, they try to save time by looking for an application or system that provides automatic recommendations. Recommender systems are automated computing processes that leverage concepts of Machine Learning, Data Mining and Artificial Intelligence towards generating product recommendations based on a user’s preferences. These systems have given a significant boost to businesses across multiple segments as a result of reduced human intervention. One similar aspect of this is content writing. It would save users a lot of time …

Empirical Evaluation Of The Shift And Scale Parameters In Batch Normalization, Yashna Peerthum

Master's Projects

Batch Normalization (BatchNorm) is a technique that enables the training of deep neural networks, especially Convolutional Neural Networks (CNN) for computer vision tasks. It has been empirically demonstrated that BatchNorm increases per- formance, stability, and accuracy, although the reasons for these improvements are unclear. BatchNorm consists of a normalization step with trainable shift and scale parameters. In this paper, we examine the role of normalization and the shift and scale parameters in BatchNorm. We implement two new optimizers in PyTorch: a version of BatchNorm that we refer to as AffineLayer, which includes the shift and scale transform without normalization, and …

Adversarial Attacks On Android Malware Detection And Classification, Srilekha Nune

Master's Projects

Recent years have seen an increase in sales of intelligent gadgets, particularly those using the Android operating system. This popularity has not gone unnoticed by malware writers. Consequently, many research efforts have been made to develop learning models that can detect Android malware. As a countermeasure, malware writers can consider adversarial attacks that disrupt the training or usage of such learning models. In this paper, we train a wide variety of machine learning models using the KronoDroid Android malware dataset, and we consider adversarial attacks on these models. Specifically, we carefully measure the decline in performance when the feature sets …

5g Mobility Management Using Satellites In Leo (Low Earth Orbit), Peter Knight

Master's Projects

As technology moves forward we find ourselves demanding faster and better quality internet. Towards that end, 5G was developed. While cell towers are already being built with 5G in mind, some of the built-in limitations of 5G mean that we may be seeing satellites with it in the near future. This development would require a drastic change in the current algorithms used for handovers. These algorithms fail to take into account the high relative velocity of the satellites and result in many unnecessary handovers which increases the likelihood of a dropped connection. This paper will propose and evaluate the effectiveness …

Codis: Community Detection Via Distributed Seed-Set Expansion On Graph Streams, Austin Anderson

Master's Projects

Community detection has been and remains a very important topic in several fields. From marketing and social networking to biological studies, community detec- tion plays a key role in advancing research in many different fields. Research on this topic originally looked at classifying nodes into discrete communities, but eventually moved forward to placing nodes in multiple communities. Unfortunately, community detection has always been a time-inefficient process, and recent data sets have been simply to large to realistically process using traditional methods. Because of this, recent methods have turned to parallelism, but all these methods, while offering sig- nificant decrease in …

Graph Neural Networks For Malware Classification, Vrinda Malhotra

Master's Projects

Malware is a growing threat to the digital world. The first step to managing this threat is malware detection and classification. While traditional techniques rely on static or dynamic analysis of malware, the generation of these features requires expert knowledge. Function call graphs (FCGs) consist of program functions as their nodes and their interprocedural calls as their edges, providing a wealth of knowledge that can be utilized to classify malware without feature extraction that requires experts. This project treats malware classification as a graph classification problem, setting node features using the Local Degree Profile (LDP) model and using different graph …

A Study On Human Face Expressions Using Convolutional Neural Networks And Generative Adversarial Networks, Sriramm Muthyala Sudhakar

Master's Projects

Human beings express themselves via words, signs, gestures, and facial emotions. Previous research using pre-trained convolutional models had been done by freezing the entire network and running the models without the use of any image processing techniques. In this research, we attempt to enhance the accuracy of many deep CNN architectures like ResNet and Senet, using a variety of different image processing techniques like Image Data Generator, Histogram Equalization, and UnSharpMask. We used FER 2013, which is a dataset containing multiple classes of images. While working on these models, we decided to take things to the next level, and we …

Consultation Summary For Proposed Declared Pest Rates 2022/2023, Department Of Primary Industries And Regional Development, Western Australia

Biosecurity published reports

In accordance with the Biosecurity and Agriculture Management (Declared Pest Account) Regulations 2014, the Minister for Agriculture and Food carries out consultation on Declared Pest Rates, to be considered prior to the rates being determined and gazetted.

This document is the Department of Primary Industries and Regional Development's response to the submissions received.

Synthesis Of Titanium Dioxide Nanoparticles With Renewable Resources And Their Applications: Review, Umut Şafak Öztürk, Ali̇me Çitak

Turkish Journal of Chemistry

Metal-oxide nanoparticles have reached a wide range of applications in the last ten years. Titanium dioxide nanoparticles stand out with their unique crystal structure and near-perfect physical and chemical properties at nanoscales (crystal size between 10-100 nm). It has created many applications with its white pigment, semiconductor state, and effective photocatalytic properties, but the synthesis of these nanoparticles is very damaging to nature. Titanium dioxide nanoparticles, which can be synthesized with toxic solvents or high-energy machines, have started to be synthesized by the green synthesis method, which has been a cheap and easy method in recent years. The application areas …

Photocatalytic Degradation Of Aquatic Organic Pollutants With Zn- And Zr-Based Metalorganic Frameworks: Zif-8 And Uio-66, Fatma Defne Çalik, Bi̇lgesu Erdoğan, Esra Yilmaz, Gi̇zem Saygi, Seher Fehi̇me Çakicioğlu Özkan

Turkish Journal of Chemistry

Water treatment has been an essential issue with the increasing population over 40 years. Researchers center on the major organic pollutants, such as dyes, pesticides, and pharmaceutical products. Photocatalytic degradation is one of the promising methods for aquatic organic pollutant treatment. Over the years, scientists have been working on developments for photocatalysts to enhance their pollutant degradation performances. From the reviewed studies, it is seen that properties like surface area, chemical, mechanical, and thermal stability, and uniform distribution of active sites are crucial, and an increase in these properties provides better degradation efficiency. In this sense, metal-organic frameworks as photocatalysts …

A Review On The Achievement Of Enzymatic Glycerol Carbonate Production, Selda Aydoğdu, Nurcan Kapucu

Turkish Journal of Chemistry

High energy demand driven by decreasing fossil fuels, and global warming because of the burning of fossil fuels necessitates the utilization of renewable and clean energy. One of these renewable energy sources is biodiesel. The increasing trend of biodiesel over the last 20 years tends to result in increasing glycerol (Gly), which is produced during the biodiesel production in 10% ratio (w/w) as a by-product. Using Gly as raw material is an alternative way to produce bio-based new products such as glycerol carbonate (GlyC). GlyC is a value-added product of Gly/vegetable oil and this product can be used as a …

Synthesis And Reactions Of Di(Thiophen-2-Yl)Alkane Diones: Cyclocondensation, Teki̇n Artunç, Abdullah Menzek

Turkish Journal of Chemistry

Known 1,6-di(thiophen-2-yl)hexane-1,6-dione (2) and novel 1,7-di(thiophen-2-yl)heptane-1,7-dione (4) were obtained from the reactions of thiophene with the corresponding diacyl chlorides. Furthermore, compounds with furan and pyrrole units in place of thiophene units in compound 2 were obtained in the same way. Bromination of 2 and 4 gave bromides regioselectively. The reaction of each of the compounds 2 and 4 in HOAc medium yielded cyclocondensation products. In total, four known and eleven novel compounds were synthesized.

Synthesis And Antioxidant Activities Of Benzylic Bromophenols Inclusive Of Natural Products, Çeti̇n Bayrak, Eda Mehtap Üç, Mohsen Rezaei, İlhami̇ Gülçi̇n, Abdullah Menzek

Turkish Journal of Chemistry

The synthesis of natural products 2-(2,3-dibromo-4,5-dihydroxyphenyl)acetic acid (1) and 2-(2,6-dibromo-3,5-dihydroxyphenyl)acetic acid (2) and as well as their derivatives 25 and 26 were carried out by substitution, hydrolysis and demethylation reactions of the corresponding four benzyl bromides. The antioxidant potentials of benzylic acid-derived bromophenols were, for the first time, appraised by several outstanding bioanalytical methods. Besides these, we estimated the antioxidant effects which were studied using the methods of DPPH·, ABTS^·+ scavenging activities, ferric (Fe³⁺) and cupric (Cu²⁺) ions and Fe³⁺-TPTZ reducing capacities. Benzylic acid-derived bromophenols were found as effective DPPH^·, and …

Investigation Of Boron Nanosized Particles Prepared With Various Surfactants And Chitosan In Terms Of Physical Stability And Cell Viability, Emrah Özakar, Mehmet Semi̇h Bi̇ngöl, Ruki̇ye Sevi̇nç Özakar

Turkish Journal of Chemistry

Nanosuspensions (NS) are one of the new generation drug carrier forms developed to overcome the deficiencies of drugs with poor water solubility or insolubility and are considered to be one of the most successful approaches to formulate compounds in recent years. Boron nitride (BN) is insoluble in water and chemically more stable than carbon, it offers better biological superiority although the application of carbon structures in the biomedical field has increased in recent years. Chitosan is a polymer with excellent processability and biocompatibility thanks to its high dielectric constant. In addition, chitosan has a high affinity for metal ions. This …

Preparation Of Moo3/Mos2-E Composite For Enhanced Photoelectrocatalytic Removal Of Antimony From Petrochemical Wastewaters, Sevi̇l Akçağlar

Turkish Journal of Chemistry

By doping of MoO₃ to MoS_2-E, MoO₃/MoS_2-E composite was produced to treat the antimony (Sb⁺⁵) from raw petrochemical industry wastewater. The effects of increasing MoO₃/MoS_2-E composite concentrations (0.01, 0.06, 0.50, 1.20, and 6 mg/L), times (5 min, 10 min, 20 min, 60 min, 80 min), and simulated sun light powers (2, 15, and 26 mW/m²) on the removal of Sb⁺⁵ was researched. According to X-ray diffraction (XRD), MoS_2-E exhibited a pure hexagonal structure with peaks at 2θ data of 15.56, 33.78, 40.59, and 61.43 cm …

Homonuclear Nickel(Ii) Metal-Organic Framework-Type Supramolecule: Adsorption And Emission Properties, Idongesit Mbonu, Olusegun Abiola, Hamzah Bawa

Turkish Journal of Chemistry

Coordination-driven self-assembly of nickel (II) ions with equimolar amounts of 1, 10 phenanthroline, and benzoic acid was used to create homonuclear nickel (II) MOF-type supramolecule. Single crystal X-ray diffraction, scanning electron microscopy, differential scanning calorimetry, photoluminescence measurement, FT-IR, UV-visible spectroscopy, and nitrogen physisorption measurement were used to characterize the compound. The single crystal X-ray diffraction study reveals that the synthesized compound is two-dimensional with pores in the structure. The homonuclear nickel (II) MOF-type supramolecule crystallized in a triclinic crystal system, with space group P-1 (No.2) and unit cell parameters a = 9.2053(4) Ǻ, b = 13.2964(5) Ǻ, c = 15.8998(6) …

The 4-(Dimethylaminoalkyl)Piperazine Inhibitors Of Α-Glucosidase: Allosteric Enzyme Inhibition And Identification Of Interacting Chemical Groups, Usman Ghani, Sajda Ashraf, Zaheer Ul Haq, Zafer Asim Kaplancikli, Fati̇h Demi̇rci̇, Yusuf Özkay, Sibtain Afzal

Turkish Journal of Chemistry

In continuation of our interest in identifying new α-glucosidase inhibitors with potential to become antidiabetic drugs, this work focuses on the study of 4-(dimethylaminoalkyl)piperazine-1-carbodithioate derivatives as α-glucosidase inhibitors. The eight heterocyclic piperazine-dithiocarbamate complexes studied in this work contain a variety of substitutions on their benzene ring exhibiting potent, noncompetitive inhibition of α-glucosidase. Dithiocarbamate and piperazine moieties are important pharmacophores with promising therapeutic prospects featuring facilitated drug delivery due to their lipophilic nature in addition to their α-glucosidase inhibitory activity. Enzyme kinetics, molecular dynamics simulations, and docking studies revealed that the target compounds bind to a new allosteric site that is …

Ultrasound Phantom With Solids Mimicking Cancerous Tissue For Needle Breast Biopsy, Işik İpek Avci Yayla, Meli̇s Bi̇lal, Artür Salmaslioğlu, Erol Erçağ, Esma Sezer, Belkis Ustamehmetoglu

Turkish Journal of Chemistry

This study aimed at synthesizing hydrogels to simulate opaque breast tissue (BT) and coloured cancerous tissues (CT) at different densities of the designed phantom to improve the biopsy-related skills along with ultrasonography. Both tissues are tear-resistant and therefore, the phantom can be trained multiple times in order to lower the price and improve the eye-hand coordination of users. For this purpose, self-healing (SH) polyacrylamide (PAAm) hydrogels (SH hydrogel) obtained by free-radical polymerization of AAm, in the presence of chemical cross-linker, BAAm, physical cross-linker stearyl methacrylate, C18, and ammonium persulfate APS as initiator were used in the design of phantoms. Psyllium …

Schiff Base Containing Pyridine Groups Functionalized Water-Soluble Phthalocyanine: Synthesis, Photo-Physicochemical Properties, And Bovine Serum Albumin Binding Behavior, Öznur Dülger, Ali̇ Erdoğmuş

Turkish Journal of Chemistry

The novel pyridine bearing schiff base substituted metal-free (9), zinc(II) phthalocyanine (10), and its quaternized derivative (11) were designed and synthesized. These phthalocyanines were fully characterized by spectroscopic methods (FT-IR, UV-Vis, MALDI-TOF, and ¹H NMR). The photo-physicochemical properties of these phthalocyanines were investigated in both DMSO and DMF for 10 and in both DMSO and aqueous solution for 11. The addition of pyridine bearing Schiff base groups as peripheral ligands showed an improvement in the photophysical and photochemical properties. In addition, a spectroscopic investigation of the binding behavior of the water-soluble zinc (II) phthalocyanine …