Physical Sciences and Mathematics Commons^™

Why Gradient Descent -- Not The Best Optimization Technique -- Works Best In Neural Networks: Qualitative Explanation, Jonatan Contreras, Martine Ceberio, Olga Kosheleva, Vladik Kreinovich

Departmental Technical Reports (CS)

In a usual Numerical Methods class, students learn that gradient descent is not an efficient optimization algorithm, and that more efficient algorithms exist, algorithms which are actually used in state-of-the-art numerical optimization packages. On the other hand, in solving optimization problems related to machine learning -- and, in particular, in currently most efficient deep learning -- gradient descent (in the form of backpropagation) is much more efficient than any of the alternatives that have been tried. How can we reconcile these two statements? In this paper, we explain that, in reality, there is no contradiction here. Namely, in usual applications …

Why Homogeneous Membranes Lead To Optimal Water Desalination: A Possible Explanation, Julio Urenda, Martine Ceberio, Olga Kosheleva, Vladik Kreinovich

Departmental Technical Reports (CS)

A recent experiment has shown that out of all possible biological membranes, homogeneous ones proved the most efficient water desalination. In this paper, we show that natural symmetry ideas lead to a theoretical explanation for this empirical fact.

Maximums Of Total Betti Numbers In Hilbert Families, Jay White

Theses and Dissertations--Mathematics

Fix a family of ideals in a polynomial ring and consider the problem of finding a single ideal in the family that has Betti numbers that are greater than or equal to the Betti numbers of every ideal in the family. Or decide if this special ideal even exists. Bigatti, Hulett, and Pardue showed that if we take the ideals with a fixed Hilbert function, there is such an ideal: the lexsegment ideal. Caviglia and Murai proved that if we take the saturated ideals with a fixed Hilbert polynomial, there is also such an ideal. We present a generalization of …

Solubility Of Additive Forms Over Local Fields, Drew Duncan

Theses and Dissertations--Mathematics

Michael Knapp, in a previous work, conjectured that every additive sextic form over $\mathbb{Q}_2(\sqrt{-1})$ and $\mathbb{Q}_2(\sqrt{-5})$ in seven variables has a nontrivial zero. In this dissertation, I show that this conjecture is true, establishing that $$\Gamma^*(6, \mathbb{Q}_2(\sqrt{-1})) = \Gamma^*(6, \mathbb{Q}_2(\sqrt{-5})) = 7.$$ I then determine the minimal number of variables $\Gamma^*(d, K)$ which guarantees a nontrivial solution for every additive form of degree $d=2m$, $m$ odd, $m \ge 3$ over the six ramified quadratic extensions of $\mathbb{Q}_2$. We prove that if $$K \in \{\mathbb{Q}_2(\sqrt{2}), \mathbb{Q}_2(\sqrt{10}), \mathbb{Q}_2(\sqrt{-2}), \mathbb{Q}_2(\sqrt{-10})\},$$ then $$\Gamma^*(d,K) = \frac{3}{2}d,$$ and if $$K \in \{\mathbb{Q}_2(\sqrt{-1}), \mathbb{Q}_2(\sqrt{-5})\},$$ then $$\Gamma^*(d,K) = …

Calculating Probable Theoretical Offspring Genotype In Fruit Flies, Megan Keller

Undergraduate Journal of Mathematical Modeling: One + Two

Being able to calculate an offspring's theoretical genotype is critical in genetic sciences. We calculate the theoretical genotype and phenotype of fruit fly offspring. Using the product rule, we determine the probability for each trait and then for each genotype. In conclusion, we calculate 64 different genotypes that are supposed to be possible, but only 8 phenotypes are possible.

Analyzing Piney Point’S Wastewater Discharge Rate, Josephina Reyman

Undergraduate Journal of Mathematical Modeling: One + Two

Implicit differentiation is used in order to find the cubic feet of water dumped into Tampa Bay per hour from the Piney Point reservoir. To get to moles from cubic feet, a series of conversions is done while Le Chatelier’s principle explains how an increase in HPO₄ ^2- (hydrogen phosphate) in Tampa Bay is going to affect algae growth. The rate of moles of HPO₄ ^2- is analyzed as well as the consequences that come with dumping copious amounts of fertilizer water into an aquatic environment.

Volume And Cost Of Cylindrical Shaped Silo With Conical Roof, Gabriel Mitzakoff Parola

Undergraduate Journal of Mathematical Modeling: One + Two

This project utilizes integral calculus to find the exact volume of a non-uniform cylindrical-shaped silo used to store wheat and calculate the cost of material utilized to build such silo. Due to its non-uniform shape, the silo is divided into two sections and the volume of each is calculated. The final volume for the silo with the measurements provided is approximately 2330.02 meters cubic and surface area of 1074.96 meters squared, which is considered to be a large capacity silo. With such a large capacity silo there are costs to be considered, such as the material cost which is calculated …

Deapsecure Computational Training For Cybersecurity Students: Improvements, Mid-Stage Evaluation, And Lessons Learned, Wirawan Purwanto, Yuming He, Jewel Ossom, Qiao Zhang, Liuwan Zhu, Karina Arcaute, Masha Sosonkina, Hongyi Wu

University Administration Publications

DeapSECURE is a non-degree computational training program that provides a solid high-performance computing (HPC) and big-data foundation for cybersecurity students. DeapSECURE consists of six modules covering a broad spectrum of topics such as HPC platforms, big-data analytics, machine learning, privacy-preserving methods, and parallel programming. In the second year of this program, to improve the learning experience, we implemented a number of changes, such as grouping modules into two broad categories, "big-data" and "HPC"; creating a single cybersecurity storyline across the modules; and introducing post-workshop (optional) "hackshops." Two major goals of these changes are, firstly, to effectively engage students to maintain …

Life In Hampton Roads Survey Press Release #7: Perceptions Of Flooding, Hurricane Evacuation, & Sheltering During Covid-19, Social Science Research Center, Old Dominion University

Life in Hampton Roads Survey Report

Life in Hampton Roads 2021 - Flooding, Hurricane Evacuation, & Sheltering During COVID-19

The changing climate and rising sea levels touch nearly every aspect of life in Hampton Roads, with some neighborhoods and communities experiencing it more acutely. But, overall, how persistent is recurrent flooding as perceived by Hampton Roads residents? This year’s survey finds that nearly 23% of respondents state that recurrent flooding is a problem in their neighborhood, a number broadly consistent with the responses seen since this question was first asked in 2013 when 23% of respondents also indicated that recurrent flooding was a problem in their …

Impacts Of Multiple Environmental Changes On Long‐Term Nitrogen Loading From The Chesapeake Bay Watershed, Shufen Pan, Zihao Bian, Hanqin Tian, Yuanzhi Yao, Raymond G. Najjar, Marjorie A.M. Friedrichs, Eileen E. Hofmann, Rongting Xu, Bowen Zhang

CCPO Publications

Excessive nutrient inputs from land, particularly nitrogen (N), have been found to increase the occurrence of hypoxia and harmful algal blooms in coastal ecosystems. To identify the main contributors of increased N loading and evaluate the efficacy of water pollution control policies, it is essential to quantify and attribute the long‐term changes in riverine N export. Here, we use a state‐of‐the‐art terrestrial–aquatic interface model to examine how multiple environmental factors may have affected N export from the Chesapeake Bay watershed since 1900. These factors include changes in climate, carbon dioxide, land use, and N inputs (i.e., atmospheric N deposition, animal …

Measuring Winds From Space To Reduce The Uncertainty In The Southern Ocean Carbon Fluxes: Science Requirements And Proposed Mission, Joellen L. Russell, David G. Long, Paul Chang, Madeline Cowell, Enrique Curchitser, Michael S. Dinniman, Charles Fellows, Paul Goodman, Eileen Hofmann, Zorana Jelenak, John Klinck, John P. Krasting, Nicole Suzanne Lovenduski, Marcus Lofverstrom, Matthew R. Mazloff, Shelley Petroy, Anjani Polit, Ernesto Rodriguez, Oscar Schofield, Ad Stoffelen, Ronald J. Stouffer, Rik Wanninkhof, Carl Weimer, Xubin Zeng

CCPO Publications

Strong winds in Southern Ocean storms drive air-sea carbon and heat fluxes. These fluxes are integral to the global climate system and the wind speeds that drive them are increasing. The current scatterometer constellation measuring vector winds remotely undersamples these storms and the higher winds within them, leading to potentially large biases in Southern Ocean wind reanalyses and the fluxes that derive from them. This observing system design study addresses these issues in two ways. First, we describe an addition to the scatterometer constellation, called Southern Ocean Storms -- Zephyr, to increase the frequency of independent observations, better constraining high …

Assessment Of Tidal Range Changes In The North Sea From 1958 To 2014, Leon Jänicke, Andra Ebener, Sönke Dangendorf, Arne Arns, Michael Schindelegger, Sebastian Niehüser, Ivan D. Haigh, Philip Woodworth, Jürgen Jensen

CCPO Publications

We document an exceptional large-spatial scale case of changes in tidal range in the North Sea, featuring pronounced trends between -2.3 mm/yr at tide gauges in the United Kingdom and up to 7 mm/yr in the German Bight between 1958 and 2014. These changes are spatially heterogeneous and driven by a superposition of local and large-scale processes within the basin. We use principal component analysis to separate large-scale signals appearing coherently over multiple stations from rather localized changes. We identify two leading principal components (PCs) that explain about 69% of tidal range changes in the entire North Sea including the …

A Recirculating Eddy Promotes Subsurface Particle Retention In An Antarctic Biological Hotspot, Katherine L. Hudson, Matthew John Oliver, Josh Kohut, Michael S. Dinniman, J. M. Klinck, Carlos Moffat, Hank Statscewich, Kim S. Bernard, William Fraser

OES Faculty Publications

Palmer Deep Canyon is one of the biological hotspots associated with deep bathymetric features along the Western Antarctic Peninsula. The upwelling of nutrient-rich Upper Circumpolar Deep Water to the surface mixed layer in the submarine canyon has been hypothesized to drive increased phytoplankton biomass productivity, attracting krill, penguins and other top predators to the region. However, observations in Palmer Deep Canyon lack a clear in-situ upwelling signal, lack a physiological response by phytoplankton to Upper Circumpolar Deep Water in laboratory experiments, and surface residence times that are too short for phytoplankton populations to reasonably respond to any locally upwelled nutrients. …

Constraining 20th‐Century Sea‐Level Rise In The South Atlantic Ocean, Thomas Frederikse, Surendra Adhikari, Tim J. Daley, Sönke Dangendorf, Roland Gehrels, Felix Landerer, Marta Marcos, Thomas L. Newton, Graham Rush, Aimée B.A. Slangen, Guy Wöppelmann

OES Faculty Publications

Sea level in the South Atlantic Ocean has only been measured at a small number of tide-gauge locations, which causes considerable uncertainty in 20th-century sea-level trend estimates in this basin. To obtain a better-constrained sea-level trend in the South Atlantic Ocean, this study aims to answer two questions. The first question is: can we combine new observations, vertical land motion estimates, and information on spatial sampling biases to obtain a likely range of 20th-century sea-level rise in the South Atlantic? We combine existing observations with recovered observations from Dakar and a high-resolution sea-level reconstruction based on salt-marsh sediments from the …

Provenance Of Early Paleogene Strata In The Bighorn Basin (Wyoming, U.S.A.): Implications For Laramide Tectonism And Basin-Scale Stratigraphic Patterns, Jessica L. Welch

WWU Graduate School Collection

The Bighorn Basin (Wyoming, U.S.A.) contains some of the best exposed and studied nonmarine early Paleogene strata. Over a century of research has produced a highly resolved record of early Paleogene terrestrial climatic and biotic change as well as extensive documentation of spatiotemporal variability in basin-scale stratigraphy. The basin also offers the opportunity to integrate these data with the uplift and erosional history of the Laramide uplifts that surround the Bighorn Basin. Herein we provide a comprehensive provenance analysis of the early Paleogene Fort Union and Willwood formations in the Bighorn Basin from paleocurrent measurements (n = 510 measurements), detrital …

A Deep Learning Approach For Real-Time Analysis Of Attendees’ Engagement In Public Events, Sujith Samuel Mathew, Manar Alkhatib, May El Barachi

All Works

Smart city analytics requires the harnessing and analysis of emotions and sentiments conveyed by images and video footage. In recent years, facial sentiment analysis attracted significant attention for different application areas, including marketing, gaming, political analytics, healthcare, and human computer interaction. Aiming at contributing to this area, we propose a deep learning model enabling the accurate emotion analysis of crowded scenes containing complete and partially occluded faces, with different angles, various distances from the camera, and varying resolutions. Our model consists of a sophisticated convolutional neural network (CNN) that is combined with pooling, densifying, flattening, and Softmax layers to achieve …

Synergygrids: Blockchain-Supported Distributed Microgrid Energy Trading, Moayad Aloqaily, Ouns Bouachir, Öznur Özkasap, Faizan Safdar Ali

All Works

Growing intelligent cities is witnessing an increasing amount of local energy generation through renewable energy resources. Energy trade among the local energy generators (aka prosumers) and consumers can reduce the energy consumption cost and also reduce the dependency on conventional energy resources, not to mention the environmental, economic, and societal benefits. However, these local energy sources might not be enough to fulfill energy consumption demands. A hybrid approach, where consumers can buy energy from both prosumers (that generate energy) and also from prosumer of other locations, is essential. A centralized system can be used to manage this energy trading that …

Real-Time Privacy Preserving Framework For Covid-19 Contact Tracing, Akashdeep Bhardwaj, Ahmed A. Mohamed, Manoj Kumar, Mohammed Alshehri, Ahed Abugabah

All Works

The recent unprecedented threat from COVID-19 and past epidemics, such as SARS, AIDS, and Ebola, has affected millions of people in multiple countries. Countries have shut their borders, and their nationals have been advised to self-quarantine. The variety of responses to the pandemic has given rise to data privacy concerns. Infection prevention and control strategies as well as disease control measures, especially real-time contact tracing for COVID-19, require the identification of people exposed to COVID-19. Such tracing frameworks use mobile apps and geolocations to trace individuals. However, while the motive may be well intended, the limitations and security issues associated …

A Parallelized Database Damage Assessment Approach After Cyberattack For Healthcare Systems, Sanaa Kaddoura, Ramzi A. Haraty, Karam Al Kontar, Omar Alfandi

All Works

In the current Internet of things era, all companies shifted from paper-based data to the electronic format. Although this shift increased the efficiency of data processing, it has security drawbacks. Healthcare databases are a precious target for attackers because they facilitate identity theft and cybercrime. This paper presents an approach for database damage assessment for healthcare systems. Inspired by the current behavior of COVID-19 infections, our approach views the damage assessment problem the same way. The malicious transactions will be viewed as if they are COVID-19 viruses, taken from infection onward. The challenge of this research is to discover the …

Deceptive Opinions Detection Using New Proposed Arabic Semantic Features, Amel Ziani, Nabiha Azizi, Didier Schwab, Djamel Zenakhra, Monther Aldwairi, Nassira Chekkai, Nawel Zemmal, Marwa Hadj Salah

All Works

Some users try to post false reviews to promote or to devalue other’s products and services. This action is known as deceptive opinions spam, where spammers try to gain or to profit from posting untruthful reviews. Therefore, we conducted this work to develop and to implement new semantic features to improve the Arabic deception detection. These features were inspired from the study of discourse parse and the rhetoric relations in Arabic. Looking to the importance of the phrase unit in the Arabic language and the grammatical studies, we have analyzed and selected the most used unit markers and relations to …

Collaborations In Environmental Initiatives For An Effective Gover- Nance Of Social-Ecological Systems: What The Scientific Literature Suggests., Elena Andriollo, Alberto Caimo, Laura Secco, Elena Pisani

Articles

Moving from the scientific literature on evaluation of environmental projects and programs, this study identifies how and under which conditions collaborations are considered effective for adaptive gover- nance of SES. The method adopted is a systematic literature review based on the quantitative and qualitative analysis of 56 articles selected through specific queries on the SCOPUS database and published from 2004 to 2020. Results of the quantitative analysis underline conditions able to make collaborations effective for adaptive governance of SES: the importance of transdisciplinary research tackling both environmental and social sciences, the perceived urgency of stakeholders to tackle environmental challenges and …

Metal Bioaccessibility In Synthetic Bodyfluids–A Way To Considerpositive And Negative Alloying Effects In Hazard Assessments, Yolanda S. Hedberg, Xuying Wang, James J. Noël, Inger Odnevall Wallinder

Chemistry Publications

Hazard classification of metal alloys is today generally based on their bulk content, an approach that seldom reflects the extent of metal release for a given environment. Such information can instead be achieved via bioelution testing under simulated physiological conditions. The use of bioelution data instead of bulk contents would hence refine the current hazard classification of alloys and enable grouping. Bioelution data have been generated for nickel (Ni) and cobalt (Co) released from several stainless steel grades, one low-alloyed steel, and Ni and Co metals in synthetic sweat, saliva and gastric fluid, for exposure periods from 2 to 168 …

New Weldable 316l Stainless Flux-Cored Wires With Reduced Cr(Vi) Fume Emissions Part 2 – Round Robin Creating Fume Emission Data Sheets, Yolanda Hedberg

Chemistry Publications

Welding fumes have been found to be carcinogenic and stainless steel welders may be at higher risk due to increased formation of hexavalent chromium (Cr(VI)). The slag-shielded methods, identified to generate most airborne particles and Cr(VI), would potentially be most harmful. With ever-stricter limits set to protect workers, measures to minimize human exposure become crucial. Austenitic stainless steel flux-cored wires of 316L type have been developed with the aim to reduce the toxicity of the welding fume without compromised usability. Collected particles were compared with fumes formed using solid, metal-cored and standard flux-cored wires. In Part 1, the new wires …

New Weldable 316l Stainless Flux-Cored Wires With Reduced Cr(Vi) Fume Emissions Part 1 – Health Aspects Of Particle Composition And Release Of Metals, Yolanda Hedberg

Chemistry Publications

Welding fumes have been found to be carcinogenic and stainless steel welders may be at higher risk due to increased formation of hexavalent chromium (Cr(VI)). The slag-shielded methods, identified to generate most airborne particles and Cr(VI), would potentially be most harmful. With ever-stricter limits set to protect workers, measures to minimize human exposure become crucial. Austenitic stainless steel flux-cored wires of 316L type have been developed with the aim to reduce the toxicity of the welding fume without compromised usability. Collected particles were compared with fumes formed using solid, metal-cored and standard flux-cored wires. The size, morphology and composition were …

Corrosion Failure Of Titanium Tubes Of A Heat Exchanger For The Heating Of Dissolving Lye, Valentin Romanovski, Yolanda S. Hedberg, Andrei Paspelau, Vitali Frantskevich, James J. Noël, Elena Romanovskaia

Chemistry Publications

Corrosion of titanium heat exchangers in the processing of sylvinite ore is undesirable from economic, safety, and process sustainability perspectives. Triggered by an industrial case, we investigated the extent of corrosion during simulated contact with sylvinite ore (in dissolving lye) in relevant conditions. Detailed characterization of the failed tubes and corrosion products was carried out to understand the mechanism of failure. Corrosion of titanium (Grade 2) tubes was investigated at room temperature, 60, 70, 80, and 90 °C. After electrochemical and surface morphology analysis, we found that pitting corrosion of the titanium tube material sharply increased above 80 °C in …

Band-Gap Tuning In Acceptor-Donor-Acceptor Boron Difluoride Formazanates, Francis L. Buguis, Michael Anghel, Joe B. Gilroy, Jasveer S. Dhindsa

Chemistry Publications

π-Conjugated molecules with acceptor-donor-acceptor (A-D-A) electronic structures are an important class of materials due to their tunable optoelectronic properties and applications in, for example, organic light-emitting diodes, nonlinear optical devices, and organic solar cells. The frontier molecular orbital energies, and thus band gaps, of these materials can be tuned by varying the donor and acceptor traits and π-electron counts of the structural components. Herein, we report the synthesis and characterization of a series of A-D-A compounds consisting of BF₂ formazanates as electron acceptors bridged by a variety of π-conjugated donors. The results, which are supported by DFT calculations, demonstrate …

Five Ps (Policies, Practices, Power Structures, Places; And People): A Framework To Analyze Systemic Inequalities, Eva Thanheiser, Lisa Weasel, Idowu Ajibade, Larry Martinez, Gina Greco

Mathematics and Statistics Faculty Publications and Presentations

This chart is part of a framework to establish institutional equity and is part of the following National Science Foundation grant project:

The Spaces of Empowerment for Equity and Diversity: Advancement Through Access (SEE-DATA) project at Portland State University (PSU) aims to identify, understand, and improve the workplace experiences and retention of faculty in STEM fields who have been traditionally minoritized and marginalized based on gender, race/ethnicity, and other intersectional identities (e.g., sexual orientation, disability, socioeconomic status, national origin, immigrant status). The project will collect, analyze, and map data about faculty’s experiences at PSU to inform programs and policies that …

Strategies To Monitor And Deter Cyberloafing In Small Businesses: A Case Study, Veronica Pugh Dooly

Walden Dissertations and Doctoral Studies

Some information technology (IT) managers working for small businesses are struggling to monitor and deter cyberloafing. Strategies are needed to help IT practitioners to discourage cyberloafing and improve productivity while maintaining employee satisfaction. Grounded in adaptive structuration theory, the purpose of this qualitative multiple-case study was to explore strategies some small business IT managers use to monitor and deter cyberloafing. The participants were nine IT managers who successfully implemented cyberloafing monitoring and deterrence strategies in the United States. Data were collected via semistructured interviews and organization employee policy handbooks (n = 4) provided by the participants. Data were analyzed using …

Mathematics Teachers’ Pedagogical Content Knowledge And Its Relation To Student Achievement, Michelle Emmalyn Peters-George

Walden Dissertations and Doctoral Studies

Students' performance in national assessments of mathematics at Grades 2, 4, and 6 has been a cause for concern in the Eastern Caribbean. Researchers have called for studies to focus on primary mathematics teachers' pedagogies rather than on laptops and curriculum; however, it is unclear how primary mathematics teachers' pedagogical knowledge influences these student’s achievement. The purpose of this quantitative study was to investigate the relationship between primary mathematics teachers' pedagogical content knowledge (mathematical knowledge for teaching, quality of instruction, and pedagogical qualifications) and student achievement, measured by national assessment scores in Grenada, controlling for teachers’ age, gender, and experience. …

A Novel Efficient Quantum Random Access Memory, Mohammed Zidan, Abdel-Haleem Abdel-Aty, Ashraf Khalil, Mahmoud Abdel-Aty, Hichem Eleuch

All Works

Owing to the significant progress in manufacturing desktop quantum computers, the quest to achieve efficient quantum random access memory (QRAM) became inevitable. In this paper, we propose a novel efficient random access memory for quantum computers. The proposed QRAM has a fixed structure and can be used efficiently to store both known and unknown classical/quantum data. The storage capacity of the proposed QRAM is more efficient than that of the classical RAMs and can be used to store both classical and quantum information. Furthermore, the proposed model can access an arbitrary location in O(1) compared with other state-of-the-art models.